U.S. patent application number 10/157215 was filed with the patent office on 2003-10-09 for minicell-producing parent cells.
Invention is credited to Berkley, Neil, Sabbadini, Roger A., Segall, Anca M., Surber, Mark W..
Application Number | 20030190749 10/157215 |
Document ID | / |
Family ID | 27808541 |
Filed Date | 2003-10-09 |
United States Patent
Application |
20030190749 |
Kind Code |
A1 |
Surber, Mark W. ; et
al. |
October 9, 2003 |
Minicell-producing parent cells
Abstract
The invention provides compositions and methods for the
production of achromosomal and anucleate cells useful for
applications such as diagnositic and therapeutic uses, as well as
research tools and agents for drug discovery.
Inventors: |
Surber, Mark W.; (Coronado,
CA) ; Sabbadini, Roger A.; (Lakeside, CA) ;
Segall, Anca M.; (San Diego, CA) ; Berkley, Neil;
(San Diego, CA) |
Correspondence
Address: |
KNOBBE MARTENS OLSON & BEAR LLP
2040 MAIN STREET
FOURTEENTH FLOOR
IRVINE
CA
92614
US
|
Family ID: |
27808541 |
Appl. No.: |
10/157215 |
Filed: |
May 28, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10157215 |
May 28, 2002 |
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10154951 |
May 24, 2002 |
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60359843 |
Feb 25, 2002 |
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60293566 |
May 24, 2001 |
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Current U.S.
Class: |
435/375 |
Current CPC
Class: |
C12N 15/70 20130101;
Y02A 90/10 20180101; G01N 33/543 20130101; C12N 15/00 20130101;
C07K 16/00 20130101; C12P 21/02 20130101; Y02A 90/26 20180101; C40B
40/02 20130101; G01N 33/5005 20130101; G01N 33/5432 20130101; C12N
15/74 20130101; C12N 15/1037 20130101; G01N 33/60 20130101 |
Class at
Publication: |
435/375 |
International
Class: |
C12N 005/10 |
Claims
1. A minicell-producing parent cell, wherein said parent cell
comprises one or more of the following: (a) an expression element
that comprises a gene operably linked to expression sequences that
are inducible and/or repressible, wherein induction or repression
of said gene regulates the copy number of an episomal expression
construct; (b) a mutation in an endogenous gene, wherein said
mutation regulates the copy number of an episomal expression
construct; (c) an expression element that comprises a gene operably
linked to expression sequences that are inducible and/or
repressible, wherein induction or repression of said gene causes or
enhances the production of minicells; and (d) a mutation in an
endogenous gene, wherein said mutation causes or enhances minicell
production.
2. The minicell-producing parent cell of claim 1, further
comprising an episomal expression construct.
3. The minicell-producing parent cell of claim 1, further
comprising a chromosomal expression construct.
4. The minicell-producing parent cell of claim 2, wherein said
expression sequences of said expression construct are inducible
and/or repressible.
5. The minicell-producing parent cell of claim 1, wherein said
minicell-producing parent cell comprises a biologically active
compound.
6. The minicell of claim 1, wherein said gene that causes or
enhances the production of minicells has a gene product that is
involved in or regulates DNA replication, cellular division,
cellular partitioning, septation, transcription, translation, or
protein folding.
7. A minicell-producing parent cell, wherein said parent cell
comprises an expression construct, wherein said expression
construct comprises expression sequences operably linked to an ORF
that encodes a protein, and a regulatory expression element,
wherein said regulatory expression element comprises expression
sequences operably linked to a regulatory gene that encodes a
factor that regulates the expression of said ORF.
8. The minicell-producing parent cell of claim 7, wherein said
expression sequences of said expression construct are inducible
and/or repressible.
9. The minicell-producing parent cell of claim 7, wherein said
expression sequences of said regulatory expression construct are
inducible and/or repressible.
10. The minicell-producing parent cell of claim 7, wherein one or
more of said expression element or said regulatory expression
element is located on a chromosome of said parent cell.
11. The minicell-producing parent cell of claim 7, wherein one or
more of said expression element or said regulatory expression
element is located on an episomal expression construct.
12. The minicell-producing parent cell of claim 11, wherein both of
said expression element and said regulatory expression element are
located on an episomal expression construct, and one or both of
said expression element and said regulatory expression element
segregates into minicells produced from said parent cell.
13. The minicell-producing parent cell of claim 7, wherein said
minicell-producing parent cell comprises a biologically active
compound.
14. The minicell-producing parent cell of claim 13, wherein said
biologically active compound segregates into minicells produced
from said parent cell.
15. The minicell-producing parent cell of claim 7, wherein said ORF
encodes a membrane protein or a soluble protein.
16. The minicell-producing parent cell of claim 7, wherein said
protein comprises secretion sequences.
17. The minicell-producing parent cell of claim 7, wherein the gene
product of said gene regulates the expression of said ORF.
18. The minicell-producing parent cell of claim 17, wherein said
gene product is a transcription factor.
19. The minicell-producing parent cell of claim 13, wherein said
gene product is a RNA polymerase.
20. The minicell-producing parent cell of claim 19, wherein said
parent cell is MC-T7.
Description
RELATED APPLICATIONS
[0001] This application claims priority to the following U.S.
patent applications:
[0002] Ser. No. 60/295,566 entitled "Minicell Compositions and
Methods" by Roger Sabbadini, filed May 24, 2001;
[0003] Ser. No. 60/359,843 entitled "Minicell Compositions and
Methods" by Sabbadini, et al., filed Feb. 25, 2002; and
[0004] Ser. No. ______ (attorney docket No. 089608-0401), entitled
"Methods of Making Minicells," by Surber, et al., filed May 24,
2002.
[0005] All of the preceding applications are hereby incorporated in
their entirety (including drawings) by reference thereto.
FIELD OF THE INVENTION
[0006] The invention is drawn to compositions and methods for the
production of achromosomal archeabacterial, eubacterial and
anucleate eukaryotic cells that are used as, e.g., therapeutics
and/or diagnostics, reagents in drug discovery and functional
proteomics, research tools, and in other applications as well.
BACKGROUND OF THE INVENTION
[0007] The following description of the background of the invention
is provided to aid in understanding the invention, but is not
admitted to describe or constitute prior art to the invention. The
contents of the articles, patents, and patent applications, and all
other documents and electronically available information mentioned
or cited in this application, are hereby incorporated by reference
in their entirety to the same extent as if each individual
publication was specifically and individually indicated to be
incorporated by reference. Applicants reserve the right to
physically incorporate into this application any and all materials
and information from any such articles, patents, patent
applications, or other documents.
[0008] Minicells are achromosomal cells that are products of
aberrant cell division, and contain RNA and protein, but little or
no chromosomal DNA. Clark-Curtiss and Curtiss III, Analysis of
Recombinant DNA Using Escherichia coli Minicells, 101 Methods in
Enzymology 347 (1983); Reeve and Mendelson, Minicells of Bacillus
subtilis. A new system for transport studies in absence of
macromolecular biosynthesis, 352 Biochim. Biophys. Acta 298-305
(1974). Minicells are capable of plasmid-directed synthesis of
discrete polypeptides in the absence of synthesis directed by mRNA
from the bacterial chromosome. Meagher et al., Protein Expression
in E. coli Minicells by Recombinant Plasmids, 10 Cell 521, 523
(1977); Roozen et al., Synthesis of Ribonucleic Acid and Protein in
Plasmid-Containing Minicells of Escherichia coli K-12, 107(1) J. of
Bacteriology 21 (1971); and Curtiss III, Research on bacterial
conjugation with minicells and minicell-producing E. coli strains,
In: Microbial Drug Resistance, Editors Susumu Mitsuhashi &
Hajime Hashimoto, p. 169 (Baltimore: University Park Press 1976).
Early descriptions of minicells include those of Adler et al.,
Genetic control of cell division in bacteria, 154 Science 417
(1966), and Adler et al. (Miniature Escherichia coli cells
deficient in DNA, 57 Proc. Nat. Acad. Sci (Wash.) 321 (1967)).
However, discovery of the production of minicells can arguably be
traced to the 1930's (Frazer and Curtiss III, Production,
Properties and Utility of Bacterial Minicells, 69 Curr. Top.
Microbiol. Immunol. 1-3 (1975)).
[0009] Prokaryotic (a.k.a. eubacterial) minicells have been used to
produce various eubacterial proteins. See, e.g., Michael Gael, et
al., The kdpF Subunit Is Part of the K+-translocating Kdp Complex
of Escherichia coli and Is Responsible for Stabilization of the
Complex in vitro, 274(53) Jn. of Biological Chemistry 37901 (1999);
Harlow, et al., Cloning and Characterization of the gsk Gene
Encoding Guanosine Kinase of Escherichia coli, 177(8) J. of
Bacteriology 2236 (1995); Carol L. Pickett, et al., Cloning,
Sequencing, and Expression of the Escherichia coli Cytolethal
Distinding Toxin Genes, 62(3) Infection & Immunity 1046 (1994);
Raimund Eck & Jorn Belter, Cloning and characterization of a
gene coding for the catechol 1,2 dioxygenase of Arthrobacter sp.
mA3, 123 Gene 87 (1993); Andreas Schlossser, et al, Subcloning,
Nucleotide Sequence, and Expression of trkG, a Gene That Encodes an
Integral Membrane Protein Involved in Potassium Uptake via the Trk
System of Escherichia coli, 173(10) J. of Bacteriology 3170 (1991);
Mehrdad Jannatipour, et al., Translocation of Vibrio harveyi N,
N'-Diacetylchitobiase to the Outer Membrane of Escherichia coli
169(8) J. of Bacteriology 3785 (1987); and Jacobs et al.,
Expression of Mycobacterium leprae genes from a Streptococcus
mutans promoter in Escherichia coli K-12, 83(6) Proc. Natl. Acad.
Sci. USA 1926 (1986);
[0010] Various bacteria have been used, or proposed to be used, as
gene delivery vectors to mammalian cells. For reviews, see
Grillot-Courvalin et al., Bacteria as gene delivery vectors for
mammalian cells, 10 Current Opinion in Biotechnology 477 (1999);
Johnsen et al., Transfer of DNA from Genetically Modified Organisms
(GMOs), Biotechnological Institute, 1-70 (2000); Sizemore et al.,
Attenuated Shigella as a DNA delivery vehicle for DNA-mediated
immunization, 270(5234) Science 299 (1995); Patrice Courvalin, et
al., Gene transfer from bacteria to mammalian cells, 318 C. R.
Acad. Sci. 1207 (1995); Sizemore, et al. Attenuated bacteria as a
DNA delivery vehicle for DNA-mediated immunization, 15(8) Vaccine
804 (1997).
[0011] U.S. Pat. No. 4,190,495, which issued Feb. 26, 1980, to
Curtiss is drawn to minicell producing strains of E. coli that are
stated to be useful for the recombinant expression of proteins.
[0012] U.S. Pat. No. 4,311,797, which issued Jan. 19, 1982 to
Khachatourians is stated to be drawn to a minicell based vaccine.
The vaccine is stated to induce the production of antibodies
against enteropathogenic E. coli cells in cattle and is stated to
be effective against coliform enteritis.
[0013] Eubacterial minicells expressing immunogens from other
prokaryotes have been described. Purcell et al., Molecular cloning
and characterization of the 15-kilodalton major immunogen of
Treponema pallidum, Infect. Immun. 57:3708, 1989.
[0014] In "Biotechnology: Promise . . . and Peril" (IDRC Reports
9:4-7, 1980) authors Fleury and Shirkie aver that George
Khachatourians at the Unveristy of Saskatchewan, Canada, "is
working on a vaccine against cholera using `minicells.`" The
minciells are said to contain "genes from the pathogenic agent,"
and the "pathogen antigens are carried on the surface of the
minicells" (p. 5, paragraph brigding the central and right
columns).
[0015] Lundstrom et al., Secretion of Semliki Forest virus membrane
glycoprotein E1 from Bacillus subtilis, Virus Res. 2:69-83, 1985,
describe the expression of the El protein of the eukaryotic virus,
Semliki Forest virus (SFV), in Bacillus minicells. The SFV E1
protein used in these studies is not the native E1 protein. Rather,
it is a fusion protein in which the N-terminal signal sequence and
C-terminal transmembrane domain have been removed and replaced with
signal sequences from a gene from Bacillus amyloliquefaciens. The
authors aver that "E1 is properly translocated through the cell
membrane and secreted" (p. 81, 1.1. 19-20), and note that "it has
been difficult to express viral membrane proteins in prokaryotes"
(p. 81, 1.27).
[0016] U.S. Pat. No. 4,237,224, which issued Dec. 2, 1980, to Cohen
and Boyer, describes the expression of X. Laevis DNA in E. coli
minicells.
[0017] U.S. patent application Ser. No. 60/293,566 (attorney docket
Nos. 078853-0401 and 089608-0201), is entitled "Minicell
Compositions and Methods," and was filed May 24, 2001, by
Sabbadini, Roger A., Berkley, Neil L., and Klepper, Robert E., and
is hereby incorporated in its entirety by reference.
[0018] Jespersen et al. describes the use of "proteoliposomes" to
generate antibodies to the AMPA receptor. Jespersen L K, Kuusinen
A, Orellana A, Keinanen K, Engberg J. Use of proteoliposomes to
generate phage antibodies against native AMPA receptor. Eur J
Biochem. 2000 Mar;267(5):1382-9
SUMMARY OF THE INVENTION
[0019] The invention is drawn to compositions and methods for the
production and use of minicells, including but not limited to
eubacterial minicells, in applications such as diagnostics,
therapeutics, research, compound screening and drug discovery, as
well as agents for the delivery of nucleic acids and other
bioactive compounds to cells.
[0020] Minicells are derivatives of cells that lack chromosomal DNA
and which are sometimes referred to as anucleate cells. Because
eubacterial and archeabacterial cells, unlike eukaryotic cells, do
not have a nucleus (a distinct organelle that contains
chromosomes), these non-eukaryotic minicells are more accurately
described as being "without chromosomes" or "achromosomal," as
opposed to "anucleate." Nonetheless, those skilled in the art often
use the term "anucleate" when referring to bacterial minicells in
addition to other minicells. Accordingly, in the present
disclosure, the term "minicells" encompasses derivatives of
eubacterial cells that lack a chromosome; derivatives of
archeabacterial cells that lack their chromosome(s), and anucleate
derivatives of eukaryotic cells. It is understood, however, that
some of the relevant art may use the terms "anucleate minicells" or
anucleate cells" loosely to refer to any of the preceeding types of
minicells.
[0021] In one aspect, the invention is drawn to a eubacterial
minicell comprising a membrane protein that is not naturally found
in a prokaryote, i.e., a membrane protein from a eukaryote or an
archeabacterium. Such minicells may, but need not, comprise an
expression element that encodes and expresses the membrane protein
that it comprises. The membrane protein may be one found in any
non-eubacterial membrane, including, by way of non-limiting
example, a cellular membrane, a nuclear membrane, a nucleolar
membrane, a membrane of the endoplasmic reticulum (ER), a membrane
of a Golgi body, a membrane of a lysosome a membrane of a
peroxisome, a caveolar membrane, an outer membrane of a
mitochondrion or a chloroplast, and an inner membrane of a
mitochondrion or a chloroplast. By way of non-limiting example, a
membrane protein may be a receptor, such as a G-protein coupled
receptor; an enzyme, such as ATPase or adenylate cyclase, a
cytochrome; a channel; a transporter; or a membrane-bound nucleic
acid binding factor, such as a transcription and/or translation
factor; signaling components; components of the electon transport
chain (ETC); or cellular antigens. A membrane fusion protein, which
is generated in vitro using molecular cloning techniques, does not
occur in nature and is thus a membrane protein that is not
naturally found in a prokaryote, even if the fusion protein is
prepared using amino acid sequences derived from eubacterial
proteins.
[0022] Minicells that have segregated from parent cells lack
chromosomal and/or nuclear components, but retain the cytoplasm and
its contents, including the cellular machinery required for protein
expression. Although chromosomes do not segregate into minicells,
extrachromosomal and/or episomal genetic expression elements will
segregate, or may be introduced into mincells after segregation
from parent cells. Thus, in one aspect, the invention is drawn to
minicells comprising an expression element, which may be an
inducible expression element, that comprises expression sequences
operably linked to an open reading frame (ORF) that encodes the
non-eubacterial membrane protein. In a related aspect, the
invention is drawn to minicell-producing host cells having an
expression element, which may be an inducible expression element,
that comprises expression sequences operably linked to an ORF that
encodes a non-eubacterial membrane protein. In a related aspect,
the invention is drawn to a method of making a eubacterial minicell
comprising a membrane protein that is not naturally found in a
prokaryote, the method comprising growing minicell-producing host
cells, the host cells having an expression element, which may be an
inducible expression element, that comprises expression sequences
operably linked to an ORF that encodes a non-eubacterial membrane
protein; and preparing minicells from the host cells. Optionally,
at any point in the method, an inducing agent is provided in order
to induce expression of an ORF that encodes a non-eubacterial
membrane protein.
[0023] In one aspect, the invention is drawn to display produced
membrane-associated protein(s) on the surface of the minicell. For
purposes of this document, the term "display" is defined as
exposure of the structure of interest on the outer surface of the
minicell. By way of non-limiting example, this structure may be an
internally expressed membrane protein or chimeric construct to be
inserted in or associated with the minicell membrane such that the
extracellular domain or domain of interest is exposed on the outer
surface of the minicell (expressed and displayed on the surface of
the minicell or expressed in the parental cell to be displayed on
the surface of the segregated minicell). In any scenario, the
"displayed" protein or protein domain is available for interaction
with extracellular components. A membrane-associated protein may
have more than one extracellular domain, and a minicell of the
invention may display more than one membrane-associated
protein.
[0024] A membrane protein displayed by eubacterial minicells-may be
a receptor. Receptors include, by way of non-limiting example,
G-coupled protein receptors, hormone receptors, and growth factor
receptors. Minicells displaying a receptor may, but need not, bind
ligands of the receptor. In therapeutic applications of this aspect
of the invention, the ligand is an undesirable compound that is
bound to its receptor and, in some aspects, is internalized or
inactivated by the minicells. In drug discovery applications of
this aspect of the invention, the ligand for the receptor may be
detectably labeled so that its binding to its receptor may be
quantified. In the latter circumstance, the minicells may be used
to identify and isolate, from a pool of compounds, one or more
compounds that inhibit or stimulate the activity of the receptor.
That is, these minicells can be used in screening assays, including
assays such as those used in high throughput screening (HTS)
systems and other drug discovery methods, for the purpose of
preparing compounds that influence the activity of a receptor of
interest.
[0025] The displayed domain of a membrane protein may be an
enzymatic domain such as on having oxidoreductase, transferase,
hydrolase, lyase, isomerase ligase, lipase, kinase, phosphatase,
protease, nuclease and/or synthetase activity. Contacting such
minicells with the appropriate substrate of the enzyme allows the
substrate to be converted to reactant. When either the substrate or
reactant is detectable, the reaction catalyzed by the
membrane-bound enzyme may be quantified. In the latter instance,
the minicells may be used to identify and isolate, from a pool of
compounds, one or more compounds that inhibit or stimulate the
activity of the enzyme represented by the displayed enzymatic
moiety. That is, these minicells can be used in screening assays,
including assays such as those used in high throughput screening
(HTS) systems and other drug discovery methods, for the purpose of
preparing compounds that influence the activity of an enzyme or
enzymatic moiety of interest.
[0026] The membrane protein displayed by minicells may be a fusion
protein, i.e., a protein that comprises a first polypeptide having
a first amino acid sequence and a second polypeptide having a
second amino acid sequence, wherein the first and second amino acid
sequences are not naturally present in the same polypeptide. At
least one polypeptide in a membrane fusion protein is a
"transmembrane domain" or "membrane-anchoring domain". The
transmembrane and membrane-anchoring domains of a membrane fusion
protein may be selected from membrane proteins that naturally occur
in a eucaryote, such as a fungus, a unicellular eucaryote, a plant
and an animal, such as a mammal including a human. Such domains may
be from a viral membrane protein naturally found in a virus such as
a bacteriophage or a eucaryotic virus, e.g., an adenovirus or a
retrovirus. Such domains may be from a membrane protein naturally
found in an archaebacterium such as a thermophile.
[0027] The displayed domain of a membrane fusion protein may be an
enzymatic domain such as one having oxidoreductase, transferase,
hydrolase, lyase, isomerase ligase, lipase, kinase, phosphatase,
protease, nuclease and/or synthetase activity. Contacting such
minicells with the appropriate substrate of the enzyme allows the
substrate to be converted to reactant. When either the substrate or
reactant is detectable, the reaction catalyzed by the
membrane-bound enzyme may be quantified. In the latter instance,
the minicells may be used to identify and isolate, from a pool of
compounds, one or more compounds that inhibit or stimulate the
activity of the enzyme represented by the displayed enzymatic
moiety. That is, these minicells can be used in screening assays,
including assays such as those used in high throughput screening
(HTS) systems and other drug discovery methods, for the purpose of
preparing compounds that influence the activity of an enzyme or
enzymatic moiety of interest.
[0028] The displayed domain of a membrane fusion protein may be a
binding moiety. By way of non-limiting example, binding moieties
used for particular purposes may be a binding moiety directed to a
compound or moiety displayed by a specific cell type or cells found
predominantly in one type of tissue, which may be used to target
minicells and their contents to specific cell types or tissues; or
a binding moiety that is directed to a compound or moiety displayed
by a pathogen, which may be used in diagnostic or therapeutic
methods; a binding moiety that is directed to an undesirable
compound, such as a toxin, which may be used to bind and preferably
internalize and/or neutralize the undesirable compound; a diseased
cell; or the binding moiety may be a domain that allows for the
minicells to be covalently or non-covalently attached to a support
material, which may be used in compositions and methods for
compound screening and drug discovery. By "diseased cell" it is
meant pathogen-infected cells, malfunctioning cells, and
dysfunctional cells, e.g., cancer cells.
[0029] In various aspects, the minicells of the invention comprise
one or more biologically active compounds. The term "biologically
active" (synonymous with "bioactive") indicates that a composition
or compound itself has a biological effect, or that it modifies,
causes, promotes, enhances, blocks, reduces, limits the production
or activity of, or reacts with or binds to an endogenous molecule
that has a biological effect. A "biological effect" may be but is
not limited to one that stimulates or causes an immunoreactive
response; one that impacts a biological process in an animal; one
that impacts a biological process in a pathogen or parasite; one
that generates or causes to be generated a detectable signal; and
the like. Biologically active compositions, complexes or compounds
may be used in therapeutic, prophylactic and diagnostic methods and
compositions. Biologically active compositions, complexes or
compounds act to cause or stimulate a desired effect upon an
animal. Non-limiting examples of desired effects include, for
example, preventing, treating or curing a disease or condition in
an animal suffering therefrom; limiting the growth of or killing a
pathogen in an animal infected thereby; augmenting the phenotype or
genotype of an animal; stimulating a prophylactic immunoreactive
response in an animal; or diagnosing a disease or disorder in an
animal.
[0030] In the context of therapeutic applications of the invention,
the term "biologically active" indicates that the composition,
complex or compound has an activity that impacts an animal
suffering from a disease or disorder in a positive sense and/or
impacts a pathogen or parasite in a negative sense. Thus, a
biologically active composition, complex or compound may cause or
promote a biological or biochemical activity within an animal that
is detrimental to the growth and/or maintenance of a pathogen or
parasite; or of cells, tissues or organs of an animal that have
abnormal growth or biochemical characteristics, such as cancer
cells.
[0031] In the context of diagnostic applications of the invention,
the term "biologically active" indicates that the composition,
complex or compound can be used for in vivo or ex vivo diagnostic
methods and in diagnostic compositions and kits. For diagnostic
purposes, a preferred biologically active composition or compound
is one that can be detected, typically (but not necessarily) by
virtue of comprising a detectable polypeptide. Antibodies to an
epitope found on composition or compound may also be used for its
detection.
[0032] In the context of prophylactic applications of the
invention, the term "biologically active" indicates that the
composition or compound induces or stimluates an immunoreactive
response. In some preferred embodiments, the immunoreactive
response is designed to be prophylactic, i.e., prevents infection
by a pathogen. In other preferred embodiments, the immunoreactive
response is designed to cause the immune system of an animal to
react to the detriment of cells of an animal, such as cancer cells,
that have abnormal growth or biochemical characteristics. In this
application of the invention, compositions, complexes or compounds
comprising antigens are formulated as a vaccine.
[0033] It will be understood by those skilled in the art that a
given composition, complex or compound may be biologically active
in therapeutic, diagnostic and prophylactic applications. A
composition, complex or compound that is described as being
"biologically active in a cell" is one that has biological activity
in vitro (i.e., in a cell culture) or in vivo (i.e., in the cells
of an animal). A "biologically active component" of a composition
or compound is a portion thereof that is biologically active once
it is liberated from the composition or compound. It should be
noted, however, that such a component may also be biologically
active in the context of the composition or compound.
[0034] In one aspect, the minicells of the invention comprise a
therapeutic agent. Such minicells may be used to deliver
therapeutic agents. In a preferred embodiment, a minicell
comprising a therapeutic agent displays a binding moiety that
specifically binds a ligand present on the surface of a cell, so
that the minicells may be "targeted" to the cell. The therapeutic
agent may be any type of compound or moiety, including without
limitation small molecules, polypeptides, antibodies and antibody
derivatives and nucleic acids. The therapeutic agent may be a drug;
a prodrug, i.e., a compound that becomes biologically active in
vivo after being introduced into a subject in need of treatment; or
an immunogen.
[0035] In one aspect, the minicells of the invention comprise a
detectable compound or moiety. As is understood by those of skill
in the art, a compound or moiety that is "detectable" produces a
signal that can detected by spectroscopic, photochemical,
biochemical, immunochemical, electromagnetic, radiochemical, or
chemical means such as fluorescence, chemifluoresence, or
chemiluminescence, electrochemilumenscence, or any other
appropriate means. A detectable compound may be a detectable
polypeptide, and such polypeptides may, but need not, be
incorporated into fusion membrane proteins of the minicell.
Detectable polypeptides or amino acid sequences, includes, by way
of non-limiting example, a green fluorescent protein (GFP), a
luciferase, a beta-galactosidase, a His tag, an epitope, or a
biotin-binding protein such as streptavidin or avidin. The
detectable compound or moiety may be a radiolabeled compound or a
radioisotope. A detectable compound or moiety may be a small
molecule such as, by way of non-limiting example, a fluorescent
dye; a radioactive iostope; or a compound that may be detected by
x-rays or electromagnetic radiation. Image enhancers as those used
for CAT and PET scans (e.g., calcium, gallidium) may be used. In
another non-limiting example, detectable labels may also include
loss of catalytic substrate or gain of catalytic product following
catalysis by a minicell displayed, solule cytoplasmic, or secreted
enzyme.
[0036] In one aspect, the invention is drawn to a minicell
comprising one or more bioactive nucleic acids or templates
thereof. By way of non-limiting example, a bioactive nucleic acid
may be an antisense oligonucleotide, an aptamer, an antisense
transcript, a ribosomal RNA (rRNA), a transfer RNA (tRNA), a
molecular decoy, or an enzymatically active nucleic acid, such as a
ribozyme. Such minicells can, but need not, comprise a displayed
polypeptide or protein on the surface of the minicell. The
displayed polypeptide or protein may be a binding moiety directed
to a compound or moiety displayed by a particular type of cell, or
to a compound or moiety displayed by a pathogen. Such minicells can
further, but need not, comprise an expression element having
eubacterial, archael, eucaryotic, or viral expression sequences
operably linked to a nucleotide sequence that serves as a template
for a bioactive nucleic acid.
[0037] In one aspect, the invention is drawn to immunogenic
minicells, i.e., minicells that display an immunogen, vaccines
comprising immunogenic minicells, antibodies and antibody
derivatives directed to immunogens displayed on immunogenic
minicells, and method of making and using immunogenic minicells and
antibodies and antibody derivatives produced therefrom in
prophylactic, diagnostic, therapeutic and research applications. A
preferred immunogen displayed by a minicell is an immunogenic
polypeptide, which is preferably expressed from an expression
element contained within the minicell in order to maximize the
amount of immunogen displayed by the immunogenic minicells. The
immunogenic polypeptide can be derived from any organism, obligate
intracelluar parasite, organelle or virus with the provisio that,
in prophylactic applications, the immunogenic polypeptide is not
derived from a prokaryote, including a eubacterial virus. The
source organism for the immunogen may be a pathogen. A minicell
displaying an immunogen derived from a pathogen is formulated into
a vaccine and, in a prophylactic application, used to treat or
prevent diseases and disorders caused by or related to the
eukaryotic or archeabacterial pathogen.
[0038] In a separate aspect, the invention is drawn to minicells
that display an immunogen derived from a nonfunctional,
dysfunctional and/or diseased cell. By way of non-limiting example,
the minicells display an immunogenic polypeptide derived from a
hyperproliferative cell, i.e., a cell that is tumorigenic, or part
of a tumor or cancer. As another non-limiting example, a cell that
is infected with a virus or an obligate intracellular parasite
(e.g., Rickettsiae) displays an immunogenic polypeptide that is
encoded by the genome of the infected cell but is aberrenatly
expressed in an infected cell. A vaccine comprising a minicell
displaying an immunogen derived from a nonfunctional, dysfunctional
and/or diseased cell is used in methods of treating or preventing
hyperproliferative diseases or disorders, including without
limitation a cell comprising an intracellular pathogen.
[0039] In one aspect, the invention is drawn to methods of using
minicells, and expression systems optimized therefore, to
manufacture, on a large scale, proteins using recombinant DNA
technology. In a related aspect, the invention is drawn to the
production, via recombinant DNA technology, and/or segration of
exogenous proteins in minicells. The minicells are enriched for the
exogenous protein, which is desirable for increased yield and
purity of the protein. In addition to protein purification, the
minicells can be used for crystallography, the study of
intracellular or extracellular protein-protein interactions, the
study of intracellular or extracellular protein-nucleic acid
interactions, the study of intracellular or extracellular
protein-membrane interactions, and the study of other biological,
chemical, or physiological event(s).
[0040] In one aspect, the invention is drawn to minicells having a
membrane protein that has an intracellular domain. By way of
non-limiting example, the intracellular domain is exposed on the
inner surface of the minicell membrane oriented towards the
cytoplasmic compartment. The intracellular protein domain is
available for interaction with intracellular components.
Intracellular components may be naturally present in the minicells
or their parent cells, or may be introduced into minicells after
segregation from parent cells. A membrane-associated protein may
have more than one intracellular domain, and a minicell of the
invention may display more than one membrane-associated
protein.
[0041] In one aspect, the invention is drawn to a minicell
comprising a membrane protein that is linked to a conjugatable
compound (a.k.a. "attachable compound"). The conjugatable compound
may be of any chemical nature and have one or more therapeutic or
detectable moities. By way of non-limiting example, a protein
having a transmembrane or membrane anchoring domain is displayed
and has the capacity to be specifically cross-linked on its
extracellular domain. Through this approach, any conjugatable
compound of interest may be quickly and easily attached to the
outer surface of minicells containing this expressed
membrane-spanning domain. In aspects of the invention wherein
minicells are used for drug delivery in vivo, a preferred
conjugatable compound is polyethylene glycol (PEG), which provides
for "stealth" minicells that are not taken as well and/or as
quickly by the reticuloendothelial system (RES). Other conjugatable
compounds include polysaccharides, polynucleotides,
lipopolysaccharides, lipoproteins, glycosylated proteins, synthetic
chemical compounds, and/or chimeric combinations of these examples
listed.
[0042] In various aspects of the invention, the minicell displays a
polypeptide or other compound or moiety on its surface. By way of
non-limiting example, a non-eubacterial membrane protein displayed
by eubacterial minicells may be a receptor. Minicells displaying a
receptor may, but need not, bind ligands of the receptor. In
therapeutic applications of this aspect of the invention, the
ligand is an undesirable compound that is bound to its receptor
and, in some aspects, is internalized by the minicells. In drug
discovery applications of this aspect of the invention, the ligand
for the receptor may be detectably labeled so that its binding to
its receptor may be quantified. In the latter circumstance, the
minicells may be used to identify and isolate, from a pool of
compounds, one or more compounds that inhibit or stimulate the
activity of the receptor. That is, these minicells can be used in
screening assays, including assays such as those used in high
throughput screening (HTS) systems and other drug discovery
methods, for the purpose of preparing compounds that influence the
activity of a receptor of interest.
[0043] The non-eubacterial membrane protein displayed by minicells
may be a fusion protein, i.e., a protein that comprises a first
polypeptide having a first amino acid sequence and a second
polypeptide having a second amino acid sequence, wherein the first
and second amino acid sequences are not naturally present in the
same polypeptide. At least one polypeptide in a membrane fusion
protein is a "transmembrane domain" or "membrane-anchoring domain".
The transmembrane and membrane-anchoring domains of a membrane
fusion protein may be selected from membrane proteins that
naturally occur in a eukaryote, such as a fungus, a unicellular
eukaryote, a plant and an animal, such as a mammal including a
human. Such domains may be from a viral membrane protein naturally
found in a virus such as a bacteriophage or a eukaryotic virus,
e.g., an adenovirus or a retrovirus. Such domains may be from a
membrane protein naturally found in an archaebacterium such as a
thermophile.
[0044] The displayed domain of a membrane fusion protein may be an
enzymatic domain such as one having the activity of a lipase, a
kinase, a phosphatase, a reductase, a protease, or a nuclease.
Contacting such minicells with the appropriate substrate of the
enzyme allows the substrate to be converted to reactant. When
either the substrate or reactant is detectable, the reaction
catalyzed by the membrane-bound enzyme may be quantified. In the
latter instance, the minicells may be used to identify and isolate,
from a pool of compounds, one or more compounds that inhibit or
stimulate the activity of the enzyme represented by the displayed
enzymatic moiety. That is, these minicells can be used in screening
assays, including assays such as those used in high throughput
screening (HTS) systems and other drug discovery methods, for the
purpose of preparing compounds that influence the activity of an
enzyme or enzymatic moiety of interest.
[0045] The displayed domain of a membrane fusion protein may be a
binding moiety. By way of non-limiting example, binding moieties
used for particular purposes may be a binding moiety directed to a
compound or moiety displayed by a specific cell type or cells found
predominantly in one type of tissue, which may be used to target
minicells and their contents to specific cell types or tissues; or
a binding moiety that is directed to a compound or moiety displayed
by a pathogen, which may be used in diagnostic or therapeutic
methods; a binding moiety that is directed to an undesirable
compound, such as a toxin, which may be used to bind and preferably
internalize and/or neutralize the undesirable compound; a diseased
cell; or the binding moiety may be a domain that allows for the
minicells to be covalently or non-covalently attached to a support
material, which may be used in compositions and methods for
compound screening and drug discovery.
[0046] In one aspect, the invention provides compositions and
methods for preparing a soluble and/or secreted protein where the
protein remains in the cytoplasm of the minicell or is secreted
following native secretory pathways for endogenous screted proteins
or is secreted using chimeric fusion to secretory signaling
sequences. By way of non-limiting example, secreted or cytoplasmic
soluble proteins may be produced for purification, targeted
therapeutic applications where the protein produced is a
therapeutic agent and is produced at the desired site of, detection
for screening or diagnostic purposes where the protein is produced
in response to a simulous and/or localization event, or to
stimulate targeted minicell-cell fusion or interaction events where
the protein produced stimulates cell-cell fusion upon targeted
stimulation.
[0047] In one aspect, the invention provides compositions and
methods for preparing antibodies and/or antibody derivatives that
recognize an immunogenic epitope present on the native form of a
membrane protein, but which is not immunogenic when the membrane
protein is denatured or when prepared as a synthetic oligopeptide.
Such antibodies and antibody derivatives are said to be
"conformation sensitive." Unlike most antibodies and antibody
derivatives prepared by using a denatured membrane protein or an
oligopeptide derived from the membrane protein, conformation
sensitive antibodies and antibody derivatives specifically bind
membrane proteins in their native state (i.e., in a membrane) with
high affinity. Conformation sensitive antibodies and antibody
derivatives are used to target compounds and compositions,
including a minicell of the invention, to a cell displaying the
membrane protein of choice. Conformation sensitive antibodies and
antibody derivatives are also used to prevent receptors from
binding their natural ligands by specifically binding to the
receptor with a high affinity and thereby limiting access of the
ligand to the receptor. Conformation sensitive antibodies and
antibody derivatives can be prepared that are specific for a
specific isoform or mutant of a membrane protein, which can be
useful in research and medical applications.
[0048] In one aspect, the invention provides biosensors comprising
minicells including, not limited to, the minicells of the
invention. An exemplary biosensor of the invention is a BIAcore
chip, i.e., a chip onto which minicells are attached, where the
minicells undergo some change upon exposure to a preselected
compound, and the change is detected using surface plasmon
resonance. A biosensor comprising minicells can be used in methods
of detecting the presence of an undesirable compound. Undesirable
compounds include but are not limited to, toxins; pollutants;
explosives, such as those in landmines or illegally present;
illegal narcotics; components of biological or chemical weapons. In
a related aspect, the invention provides a device comprising a
microchip operatively associated with a biosensor comprising a
minicell. The device can further comprise an actuator that performs
a responsive function when the sensor detects a preselected level
of a marker.
[0049] In one aspect, the invention provides minicells that may be
used as research tools and/or kits comprising such research tools.
The minicells of the invention may be used as is, or incorporated
into research tools useful for scientific research regarding all
amino acid comprising compounds including, but not limited to
membrane-associated proteins, chimeric membrane fusion proteins,
and soluble proteins. Such scientific research includes, by way of
non-limiting example, basic research, as well as pharmacological,
diagnostic, and pharmacogenetic studies. Such studies may be
carried out in vivo or in vitro.
[0050] In one aspect, the invention is drawn to archaebacterial
minicells. In a related aspect, the invention is drawn to
archaebacterial minicells comprising at least one exogenous
protein, that is, a protein that is not normally found in the
parent cell, including without limitation fusion proteins. The
archaebacterial minicells of the invention optionally comprise an
expression element that directs the production of the exogenous
protein(s).
[0051] In other aspects, the invention is drawn to methods of
preparing the minicells, protoplasts, and protoplasts.TM. of the
invention for various applications including but not limited to
diagnostic, therapeutic, research and screening applications. In a
related aspect, the invention is drawn to pharmaceutical
compositions, reagents and kits comprising minicells.
[0052] In each aspect and embodiment of the invention, unless
stated otherwise, embodiments wherein the minicell is a eubacterial
minicell, a poroplast, a spheroplast or a protoplast exist.
[0053] In a first aspect, the invention provides a minicell
comprising a membrane protein selected from the group consisting of
a eukaryotic membrane protein, an archeabacterial membrane protein
and an organellar membrane protein. In another embodiment, wherein
the minicell comprises a biologically active compound. By way of
non-limiting example, the biologically active compound is a
radioisotope, a polypeptide, a nucleic acid or a small
molecule.
[0054] In another embodiment, the minicell comprises a expression
construct, wherein the first expression construct comprises
expression sequences operably linked to an ORF that encodes a
protein. In another embodiment, the ORF encodes the membrane
protein. In another embodiment, the expression sequences that are
operably linked to an ORF are inducible and/or repressible.
[0055] In another aspect, the minicell comprises a second
expression construct, wherein the second expression construct
comprises expression sequences operably linked to a gene. In
another embodiment, the expression sequences that are operably
linked to a gene are inducible and/or repressible. In a related
embodiment, the gene product of the gene regulates the expression
of the ORF that encodes the protein. A factor that "regulates" the
expression of a gene or a gene product directly or indirectly
initiates, enhances, quickens, slows, terminates, limits or
completely blocks expression of a gene. In different embodiments,
the gene product of the gene is a nucleic acid or a polypeptide.
The polypeptide can be of any type, including but not limited to a
membrane protein, a soluble protein or a secreted protein. A
membrane protein can be a membrane fusion protein comprising a
first polypeptide, which comprises at least one transmembrane
domain or at least one membrane anchoring domain; and a second
polypeptide.
[0056] In one aspect, the invention provides a minicell comprising
a membrane fusion protein, the fusion protein comprising a first
polypeptide, the first polypeptide comprising at least one
transmembrane domain or at least one membrane anchoring domain; and
a second polypeptide, wherein the second polypeptide is not derived
from a eubacterial protein and is neither a His tag nor a
glutathione-S-transferase polypeptide. In various embodiments, the
minicell is a eubacterial minicell, a poroplast, a spheroplast or a
protoplast. In one embodiment, the minicell comprises a
biologically active compound.
[0057] In one aspect, the invention provides a minicell comprising
a membrane conjugate, wherein the membrane conjugate comprises a
membrane protein chemically linked to a conjugated compound. In one
embodiment, the conjugated compound is selected from the group
consisting of a nucleic acid, a polypeptide, a lipid and a small
molecule.
[0058] In one aspect, the invention provides a method for making
minicells, comprising (a) culturing a minicell-producing parent
cell, wherein the parent cell comprises an expression construct,
wherein the expression construct comprises a gene operably linked
to expression sequences that are inducible and/or repressible, and
wherein induction or repression of the gene causes or enhances the
production of minicells; and (b) separating the minicells from the
parent cell, thereby generating a composition comprising minicells,
wherein an inducer or repressor is present within the parent cells
during one or more steps and/or between two or more steps of the
method. In one embodiment, the method further comprises (c)
purifying the minicells from the composition.
[0059] Relevant gene products are factors involved in or modulating
DNA replication, cellular division, cellular partitioning,
septation, transcription, translation, or protein folding. The
minicells are separated from parent cells by processes such as
centrifugation, ultracentrifugation, density gradation,
immunoaffinity, immunoprecipitation and other techniques described
herein.
[0060] In one embodiment, the minicell is a poroplast, and the
method further comprises (d) treating the minicells with an agent,
or incubating the minicells under a set of conditions, that
degrades the outer membrane of the minicell. The outer membrane is
degraded by treatment with an agent selected from the group
consisting of EDTA, EGTA, lactic acid, citric acid, gluconic acid,
tartaric acid, polyethyleneimine, polycationic peptides, cationic
leukocyte peptides, aminoglycosides, aminoglycosides, protamine,
insect cecropins, reptilian magainins, polymers of basic amino
acids, polymixin B, chloroform, nitrilotriacetic acid and sodium
hexametaphosphate; by exposure to conditions selected from the
group consisting of osmotic shock and insonation; and by other
methods described herein.
[0061] In one embodiment, further comprising removing one or more
contaminants from the composition. Representative contaminants are
LPS and peptidoglycan. In a representative embodiment, LPS is
removed by contacting the composition to an agent that binds or
degrades LPS. At least about 50%, preferably about 65% to about
75%, more preferably 95%, most preferably 99% or >99% of LPS is
removed from an initial preparation of minicells. In a related
embodiment, the minicell-producing parent cell comprises a mutation
in a gene required for lipopolysaccharide synthesis.
[0062] In on embodiment, the minicell is a spheroplast, and the
method further comprises (d) treating the minicells with an agent,
or incubating the minicells under a set of conditions, that
disrupts or degrades the outer membrane; and (e) treating the
minicells with an agent, or incubating the minicells under a set of
conditions, that disrupts or degrades the cell wall. The agent that
disrupts or degrades the cell wall can be. e.g., a lysozyme, and
the set of conditions that disrupts or degrades the cell wall can
be, e.g., incubation in a hypertonic solution.
[0063] In one embodiment, the minicell is a protoplast, and the
method further comprises (d treating the minicells with an agent,
or incubating the minicells under a set of conditions, that disrupt
or degrade the outer membrane; (e) treating the minicells with an
agent, or incubating the minicells under a set of conditions, that
disrupts or degrades the cell wall, in order to generate a
composition that comprises protoplasts; and (f) purifying
protoplasts from the composition. In one embodiment, the method
further comprises preparing a denuded minicell from the minicell.
In one embodiment, the method further comprises covalently or
non-covalently linking one or more components of the minicell to a
conjugated moiety.
[0064] In one aspect, the invention provides a L-form minicell
comprising (a) culturing an L-form eubacterium, wherein the
eubacterium comprises one or more of the following: (i) an
expression element that comprises a gene operably linked to
expression sequences that are inducible and/or repressible, wherein
induction or repression of the gene regulates the copy number of an
episomal expression construct; (ii) a mutation in an endogenous
gene, wherein the mutation regulates the copy number of an episomal
expression construct; (iii) an expression element that comprises a
gene operably linked to expression sequences that are inducible
and/or repressible, wherein induction or repression of the gene
causes or enhances the production of minicells; and (iv) a mutation
in an endogenous gene, wherein the mutation causes or enhances
minicell production; (b) culturing the L-form minicell-producing
parent cell in media under conditions wherein minicells are
produced; and (c) separating the minicells from the parent cell,
thereby generating a composition comprising L-form minicells,
wherein an inducer or repressor is present within the minicells
during one or more steps and/or between two or more steps of the
method. In one embodiment, the method further comprises (d)
purifying the L-form minicells from the composition.
[0065] In one aspect, the invention provides a method of producing
a protein, comprising (a) transforming a minicell-producing parent
cell with an expression element that comprises expression sequences
operably linked to a nucleic acid having an ORF that encodes the
protein; (b) culturing the minicell-producing parent cell under
conditions wherein minicells are produced; and (c) purifying
minicells from the parent cell, (d) purifying the protein from the
minicells, wherein the ORF is expressed during step (b), between
steps (b) and (c), and during step (c).
[0066] In one embodiment, the expression elements segregate into
the minicells, and the ORF is expressed between steps (c) and (d).
In one embodiment, the protein is a soluble protein contained
within the minicells, and the method further comprises (e) lysing
the minicells.
[0067] In one embodiment, the protein is a secreted protein, and
the method further comprises (e) collecting a composition in which
the minicells are suspended or with which the minicells are in
contact.
[0068] In one embodiment, the expression sequences to which the ORF
is operably linked are inducible, wherein the method further
comprises adding an inducing agent between steps (a) and (b);
during step (b); and between steps (b) and (c).
[0069] In one embodiment, the expression sequences to which the ORF
is operably linked are inducible, wherein the expression elements
segregate into the minicells, the method further comprises adding
an inducing agent after step (c).
[0070] In one embodiment, the method further comprises (e)
preparing poroplasts from the minicells, wherein the ORF is
expressed during step (b); between steps (b) and (c); during step
(c); between step (c) and step (d) when the expression elements
segregate into the minicells; and/or after step (d) when the
expression elements segregate into the minicells.
[0071] In one embodiment, the method further comprises (f)
purifying the protein from the poroplasts.
[0072] In one embodiment, the method further comprises (e)
preparing spheroplasts from the minicells, wherein the ORF is
expressed during step (b), between steps (b) and (c), during step
(c), between steps (c) and (d) and/or after step (d).
[0073] In one embodiment, the method further comprises (f)
purifying the protein from the spheroplasts.
[0074] In one embodiment, the method further comprises (e)
preparing protoplasts from the minicells, wherein the ORF is
expressed during step (b), between steps (b) and (c), during step
(c), between steps (c) and (d) and/or after step (d).
[0075] In one embodiment, the method further comprises (f)
purifying the protein from the protoplasts.
[0076] In one embodiment, the method further comprises (e)
preparing membrane preparations from the minicells, wherein the ORF
is expressed during step (b), between steps (b) and (c), during
step (c), between steps (c) and (d) and/or after step (d).
[0077] In one embodiment, the method further comprises (f)
purifying the protein from the membrane preparations.
[0078] In one embodiment, the minicell-producing parent cell is an
L-form bacterium.
[0079] In one aspect, the invention provides a method of producing
a protein, comprising (a) transforming a minicell with an
expression element that comprises expression sequences operably
linked to a nucleic acid having an ORF that encodes the protein;
and (b) incubating the minicells under conditions wherein the ORF
is expressed.
[0080] In one embodiment, the method further comprises (c)
purifying the protein from the minicells.
[0081] In one aspect, the invention provides a method of producing
a protein, comprising (a) transforming a minicell-producing parent
cell with an expression element that comprises expression sequences
operably linked to a nucleic acid having an ORF that encodes a
fusion protein comprising the protein and a polypeptide, wherein a
protease-sensitive amino acid sequence is positioned between the
protein and the polypeptide; (b) culturing the minicell-producing
parent cell under conditions wherein minicells are produced; (c)
purifying minicells from the parent cell, wherein the ORF is
expressed during step (b); between steps (b) and (c); and/or after
step (c) when the expression elements segregate into the minicells;
and (d) treating the minicells with a protease that cleaves the
sensitive amino acid sequence, thereby separating the protein from
the polypeptide.
[0082] In one aspect, the invention provides a poroplast, the
poroplast comprising a vesicle, bonded by a membrane, wherein the
membrane is an eubacterial inner membrane, wherein the vesicle is
surrounded by a eubacterial cell wall, and wherein the eubacterial
inner membrane is accessible to a compound in solution with the
poroplast. In one embodiment, the poroplast is a cellular
poroplast. The compound has a molecular weight of at least 1 kD,
preferably at least about 0.1 to about 1 kD, more preferably from
about 1, 10 or 25 kD to about 50 kD, and most preferably from about
75 or about 100 kD to about 150 or 300 kD.
[0083] In one embodiment, the poroplast comprises an exogenous
nucleic acid, which may be an expression construct. In one
embodiment, the expression construct comprises an ORF that encodes
an exogenous protein, wherein the ORF is operably linked to
expression sequences. In one embodiment, the exogenous protein is a
fusion protein, a soluble protein or a secreted protein. In one
embodiment, the exogenous protein is a membrane protein, and is
preferably accessible to compounds in solution with the poroplast.
In one embodiment, poroplasts are placed in a hypertonic solution,
wherein 90% or more of an equivalent amount of spheroplasts or
protoplasts lyse in the solution under the same conditions.
[0084] In one embodiment, the membrane protein is selected from the
group consisting of a eukaryotic membrane protein, an
archeabacterial membrane protein, and an organellar membrane
protein. In one embodiment, the membrane protein is a fusion
protein, the fusion protein comprising a first polypeptide, the
first polypeptide comprising at least one transmembrane domain or
at least one membrane anchoring domain; and a second polypeptide,
wherein the second polypeptide is displayed by the poroplast. In
one embodiment, the second polypeptide is displayed on the external
side of the eubacterial inner membrane. The second polypeptide can
be an enzyme moiety, a binding moiety, a toxin, a cellular uptake
sequence, an epitope, a detectable polypeptide, and a polypeptide
comprising a conjugatable moiety. An enzyme moiety is a polypeptide
derived from, by way of non-limiting example, a cytochrome P450, an
oxidoreductase, a transferase, a hydrolase, a lyase, an isomerase,
a ligase or a synthetase.
[0085] In one embodiment, the poroplast comprises a membrane
component that is chemically linked to a conjugated compound.
[0086] In one embodiment, the expression construct comprises one or
more DNA fragments from a genome or cDNA. In one embodiment, the
exogenous protein has a primary amino acid sequence predicted from
a nucleic acid sequence.
[0087] In one aspect, the invention provides a solid support
comprising a minicell. In various embodiments, the solid support is
a dipstick, a bead or a mictrotiter multiwell plate. In one
embodiment, the minicell comprises a detectable compound, which may
be a colorimetric, fluorescent or radioactive compound.
[0088] In one embodiment, the minicell displays a membrane
component selected from the group consisting of (i) a eukaryotic
membrane protein, (ii) an archeabacterial membrane protein, (iii)
an organellar membrane protein, (iv) a fusion protein comprising at
least one transmembrane domain or at least one membrane anchoring
domain, and (v) a membrane conjugate comprising a membrane
component chemically linked to a conjugated compound.
[0089] In one embodiment, the membrane component is a receptor. In
a related embodiment, the solid support further comprises a
co-receptor. In one embodiment, the minicell displays a binding
moiety.
[0090] In one aspect, the invention provides a solid support
comprising a minicell, wherein the minicell displays a fusion
protein, the fusion protein comprising a first polypeptide that
comprises at least one transmembrane domain or at least one
membrane anchoring domain, and a second polypeptide. In various
embodiments, the second polypeptide comprises a binding moiety or
an enzyme moiety.
[0091] In one aspect, the invention provides a solid support
comprising a minicell, wherein the minicell comprises a membrane
conjugate comprising a membrane component chemically linked to a
conjugated compound. In one embodiment, the conjugated compound is
a spacer. In one embodiment, the spacer is covalently linked to the
solid support. In one embodiment, the conjugated compound is
covalently linked to the solid support.
[0092] In one aspect, the invention provides a minicell comprising
a biologically active compound, wherein the minicell displays a
ligand or binding moiety, wherein the ligand or binding moiety is
part of a fusion protein comprising a first polypeptide that
comprises at least one transmembrane domain or at least one
membrane anchoring domain and a second polypeptide that comprises a
binding moiety, and the minicell is a poroplast, spheroplast or
protoplast.
[0093] In one aspect, the invention provides a eubacterial minicell
comprising a biologically active compound, wherein the minicell
displays a binding moiety, wherein the binding moiety is selected
from the group consisting of (a) a eukaryotic membrane protein; (b)
an archeabacterial membrane protein; (c) an organellar membrane
protein; and (d) a fusion protein, the fusion protein comprising a
first polypeptide, the first polypeptide comprising at least one
transmembrane domain or at least one membrane anchoring domain; and
a second polypeptide, wherein the second polypeptide is not derived
from a eubacterial protein and is neither a His tag nor a
glutathione-S-transferase polypeptide, and wherein the polypeptide
comprises a binding moiety.
[0094] In one embodiment, the binding moiety is selected from the
group consisting of an antibody, an antibody derivative, a receptor
and an active site of a non-catalytic derivative of an enzyme. In a
preferred embodiment, the binding moiety is a single-chain
antibody. In one embodiment, one of the ORFs encodes a protein that
comprises the binding moiety.
[0095] In one embodiment, the binding moiety is directed to a
ligand selected from the group consisting of an epitope displayed
on a pathogen, an epitope displayed on an infected cell and an
epitope displayed on a hyperproliferative cell.
[0096] In one embodiment, the invention further comprises a first
and second nucleic acid, wherein the first nucleic acid comprises
eukaryotic expression sequences operably linked to a first ORF, and
a second nucleic acid, wherein the second nucleic acid comprises
eubacterial expression sequences operably linked to a second
ORF.
[0097] In one embodiment, the eubacterial expression sequences are
induced and/or derepressed when the binding moiety is in contact
with a target cell. In a variant embodiment, the eukaryotic
expression sequences are induced and/or derepressed when the
nucleic acid is in the cytoplasm of a eukaryotic cell. In related
embodiments, the protein encoded by the first ORF comprises
eukaryotic secretion sequences and/or the protein encoded by the
second ORF comprises eubacterial secretion sequences.
[0098] In one aspect, the invention provides a method of
associating a radioactive compound with a cell, wherein the cell
displays a ligand specifically recognized by a binding moiety,
comprising contacting the cell with a minicell that comprises the
radioactive compound and displays the binding moiety. In a
diagnostic embodiment, the amount of radiation emitted by the
radioactive isotope is sufficient to be detectable. In a
therapeutic embodiment, the amount of radiation emitted by the
radioactive isotope is sufficient to be cytotoxic. In one
embodiment, the ligand displayed by the cell is selected from the
group consisting of an epitope displayed on a pathogen, an epitope
displayed on an infected cell and an epitope displayed on a
hyperproliferative cell. In one embodiment, the binding moiety is
selected from the group consisting of an antibody, an antibody
derivative, a channel protein and a receptor, and is preferably a
single-chain antibody. In other embodiments, the binding moiety is
an aptamer or a small molecule. In one embodiment, the ligand is
selected from the group consisting of a cytokine, hormone, and a
small molecule.
[0099] In one aspect, the invention provides a method of delivering
a biologically active compound to a cell, wherein the cell displays
a ligand specifically recognized by a binding moiety, comprising
contacting the cell with a minicell that displays the binding
moiety, wherein the minicell comprises the biologically active
compound, and wherein the contents of the minicell are delivered
into the cell from a minicell bound to the cell. In one embodiment,
the biologically active compound is selected from the group
consisting of a nucleic acid, a lipid, a polypeptide, a radioactive
compound, an ion and a small molecule.
[0100] In one embodiment, the membrane of the minicell comprises a
system for transferring a molecule from the interior of a minicell
into the cytoplasm of the cell. A representative system for
transferring a molecule from the interior of a minicell into the
cytoplasm of the cell is a Type III secretion system.
[0101] In one embodiment, the minicell further comprises a first
and second nucleic acid, wherein the first nucleic acid comprises
eukaryotic expression sequences operably linked to a first ORF, and
a second nucleic acid, wherein the second nucleic acid comprises
eubacterial expression sequences operably linked to a second ORF.
In one embodiment, one of the ORFs encodes a protein that comprises
the binding moiety. In one embodiment, the eubacterial expression
sequences are induced and/or derepressed when the binding moiety is
in contact with a target cell. In one embodiment, the eukaryotic
expression sequences are induced and/or derepressed when the
nucleic acid is in the cytoplasm of a eukaryotic cell. In one
embodiment, the protein encoded by the first ORF comprises
eukaryotic secretion sequences and/or the protein encoded by the
second ORF comprises eubacterial secretion sequences. In one
embodiment, the ligand is selected from the group consisting of a
cytokine, hormone, and a small molecule.
[0102] In one aspect, the invention provides a minicell displaying
a synthetic linking moiety, wherein the synthetic linking moiety is
covalenty or non-covalently attached to a membrane component of the
mincell.
[0103] In one aspect, the invention provides a sterically
stabilized minicell comprising a displayed moiety that has a longer
half-life in vivo than a wild-type minicell, wherein the displayed
moiety is a hydrophilic polymer that comprises a PEG moiety, a
carboxylic group of a polyalkylene glycol or PEG stearate.
[0104] In one aspect, the invention provides a minicell having a
membrane comprising an exogenous lipid, wherein a minicell
comprising the exogenous lipid has a longer half-life in vivo than
a minicell lacking the exogenous lipid, and wherein the minicell is
selected from the group consisting of a eubacterial minicell, a
poroplast, a spheroplast and a protoplast. In one embodiment, the
exogenous lipid is a derivitized lipid which may, by way of
non-limiting example, be phosphatidylethanolamine derivatized with
PEG, DSPE-PEG, PEG stearate; PEG-derivatized phospholipids, a PEG
ceramide or DSPE-PEG.
[0105] In one embodiment, the exogenous lipid is not present in a
wild-type membrane, or is present in a different proportion than is
found in minicells comprising a wild-type membrane. The exogenous
lipid can be a ganglioside, sphingomyelin, monosialoganglioside
GM1, galactocerebroside sulfate,
1,2-sn-dimyristoylphosphatidylcholine, phosphatidylinositol and
cardiolipin.
[0106] In one embodiment, the linking moiety is non-covalently
attached to the minicell. In one embodiment, one of the linking
moiety and the membrane component comprises biotin, and the other
comprises avidin or streptavidin. In one embodiment, the synthetic
linking moiety is a cross-linker. In one embodiment, the
cross-linker is a bifunctional cross-linker.
[0107] In one aspect, the invention provides a method of
transferring a membrane protein from a minicell membrane to a
biological membrane comprising contacting a minicell to the
biological membrane, wherein the minicell membrane comprises the
membrane protein, and allowing the mincell and the biological
membrane to remain in contact for a period of time sufficient for
the transfer to occur.
[0108] In one embodiment, the biological membrane is a cytoplasmic
membrane or an organellar membrane. In one embodiment, the
biological membrane is a membrane selected from the group
consisting of a membrane of a pathogen, a membrane of an infected
cell and a membrane of a hyperproliferative cell. In one
embodiment, the biological membrane is the cytoplasmic membrane of
a recipient cell, which may be a cultured cell and a cell within an
organism. In one embodiment, the biological membrane is present on
a cell that has been removed from an animal, the contacting occurs
in vitro, after which the cell is returned to the organism.
[0109] In one embodiment, the membrane protein is an enzyme. In
this embodiment, the membrane protein having enzymatic activity is
selected from the group consisting of a cytochrome P450 and a
fusion protein, the fusion protein comprising a first polypeptide,
the first polypeptide comprising at least one polypeptide, wherein
the second polypeptide has enzymatic acitivity.
[0110] In one embodiment, the membrane protein is a membrane fusion
protein, the membrane fusion protein comprising a first
polypeptide, the first polypeptide comprising at least one
transmembrane domain or at least one membrane anchoring domain; and
a second polypeptide.
[0111] In one embodiment, the second polypeptide is a biologically
active polypeptide. In one embodiment, the minicell displays ligand
or a binding moiety.
[0112] In one aspect, the invention provides a minicell that
comprises an expression construct comprising an ORF encoding a
membrane protein operably linked to expression sequences, wherein
the expression sequences are induced and/or derepressed when the
minicell is in contact with a target cell.
[0113] In one embodiment, the biological membrane is a cytoplasmic
membrane or an organellar membrane. In one embodiment, the
biological membrane is a membrane selected from the group
consisting of a membrane of a pathogen, a membrane of an infected
cell and a membrane of a hyperproliferative cell. In one
embodiment, the minicell displays a ligand or a binding moiety
selected from the group consisting of an antibody, an antibody
derivative, an aptamer and a small molecule. In one embodiment, the
membrane protein is a membrane fusion protein, the membrane fusion
protein comprising a first polypeptide, the first polypeptide
comprising at least one transmembrane domain or at least one
membrane anchoring domain; and a second polypeptide. In one
embodiment, the ligand is selected from the group consisting of a
cytokine, hormone, and a small molecule.
[0114] In one aspect, the invention provides a pharmaceutical
composition comprising a minicell, wherein the minicell displays a
membrane protein, wherein the membrane protein is selected from the
group consisting of a eukaryotic membrane protein, an
archeabacterial membrane protein and an organellar membrane
protein. In one embodiment, the membrane protein is selected from
the group consisting of a receptor, a channel protein, a cellular
adhesion factor and an integrin. In one embodiment, the
pharmaceutical formulation further comprises an adjuvant. In one
embodiment, the membrane protein comprises a polypeptide epitope
displayed by a hyperproliferative cell. In one embodiment, the
membrane protein comprises an epitope displayed by a eukaryotic
pathogen, an archeabacterial pathogen, a virus or an infected
cell.
[0115] In one aspect, the invention provides a pharmaceutical
composition comprising a minicell, wherein the minicell displays a
membrane protein that is a fusion protein, the fusion protein
comprising (i) a first polypeptide, the first polypeptide
comprising at least one transmembrane domain or at least one
membrane anchoring domain; and (ii) a second polypeptide, wherein
the second polypeptide is not derived from a eubacterial protein.
In one embodiment, the pharmaceutical formulation further comprises
an adjuvant. In one embodiment, the second polypeptide comprises a
polypeptide epitope displayed by a hyperproliferative cell. In one
embodiment, the membrane protein comprises an epitope displayed by
a eukaryotic pathogen, an archeabacterial pathogen, a virus or an
infected cell.
[0116] In one aspect, the invention provides a pharmaceutical
composition comprising a minicell, wherein the minicell displays a
membrane conjugate, wherein the membrane conjugate comprises a
membrane component chemically linked to a conjugated compound. In
one embodiment, the membrane protein is selected from the group
consisting of a receptor, a channel protein, a cellular adhesion
factor and an integrin. In one embodiment, the pharmaceutical
further comprises an adjuvant. In one embodiment, the membrane
component is a polypeptide comprising at least one transmembrane
domain or at least one membrane anchoring domain, or a lipid that
is part of a membrane. In one embodiment, the conjugated compound
is a polypeptide, and the chemical linkage between the membrane
compound and the conjugated compound is not a peptide bond. In one
embodiment, the conjugated compound is a nucleic acid. In one
embodiment, the conjugated compound is an organic compound. In one
embodiment, the organic compound is selected from the group
consisting of a narcotic, a toxin, a venom, a sphingolipid and a
soluble protein.
[0117] In one aspect, the invention provides a method of making a
pharmaceutical composition comprising a minicell, wherein the
minicell displays a membrane protein, wherein the membrane protein
is selected from the group consisting of a eukaryotic membrane
protein, an archeabacterial membrane protein and an organellar
membrane protein. In one embodiment, the method further comprises
adding an adjuvant to the pharmaceutical formulation. In one
embodiment, the method further comprises desiccating the
formulation. In one embodiment, the method further comprises adding
a suspension buffer to the formulation. In one embodiment, the
method further comprises making a chemical modification of the
membrane protein. In one embodiment, the chemical modification is
selected from the group consisting of glycosylation,
deglycosylation, phosphorylation, dephosphorylation and
proteolysis. In one aspect, the invention provides a method of
making a pharmaceutical composition comprising a minicell, wherein
the minicell displays a membrane protein that is a fusion protein,
the fusion protein comprising (i) a first polypeptide, the first
polypeptide comprising at least one transmembrane domain or at
least one membrane anchoring domain; and (ii) a second polypeptide,
wherein the second polypeptide is not derived from a eubacterial
protein.
[0118] In one aspect, the invention provides a method of making a
pharmaceutical formulation comprising a minicell, wherein the
minicell displays a membrane conjugate, wherein the membrane
conjugate comprises a membrane component chemically linked to a
conjugated compound. In one embodiment, the method further
comprises adding an adjuvant to the pharmaceutical formulation. In
one embodiment, the membrane component is a polypeptide comprising
at least one transmembrane domain or at least one membrane
anchoring domain, or a lipid that is part of a membrane. In one
embodiment, the conjugated compound is a polypeptide, and the
chemical linkage between the membrane compound and the conjugated
compound is not a peptide bond. In one embodiment, the conjugated
compound is a nucleic acid. In one embodiment, the conjugated
compound is an organic compound. In one embodiment, the organic
compound is selected from the group consisting of a narcotic, a
toxin, a venom, and a sphingclipid.
[0119] In one aspect, the invention provides a method of detecting
an agent that is specifically bound by a binding moiety, comprising
contacting a minicell displaying the binding moiety with a
composition known or suspected to contain the agent, and detecting
a signal that is modulated by the binding of the agent to the
binding moiety. In one embodiment, the agent is associated with a
disease. In one embodiment, the minicell comprises a detectable
compound. In one embodiment, the binding moiety is antibody or
antibody derivative. In one embodiment, the composition is an
environmental sample. In one embodiment, the composition is a
biological sample. In one embodiment, the biological sample is
selected from the group consisting of blood, serum, plasma, urine,
saliva, a biopsy sample, feces and a skin patch.
[0120] In one aspect, the invention provides a method of in situ
imaging of a tissue or organ, comprising administering to an
organism a minicell comprising an imaging agent and a binding
moiety and detecting the imaging agent in the organism.
[0121] In one embodiment, the minicell is a eubacterial minicell, a
poroplast, a spheroplast or a protoplast. In one embodiment, the
binding moiety is an antibody or antibody derivative. In one
embodiment, the binding moiety specifically binds a cell surface
antigen. In one embodiment, the cell surface antigen is an antigen
displayed by a tumorigenic cell, a cancer cell, and an infected
cell. In one embodiment, the cell surface antigen is a
tissue-specific antigen. In one embodiment, the method of imaging
is selected from the group consisting of magnetic resonance
imaging, ultrasound imaging; and computer axaial tomography (CAT).
In one aspect, the invention provides a device comprising a
microchip operatively associated with a biosensor comprising a
minicell, wherein the microchip comprises or contacts the minicell,
and wherein the minicell displays a binding moiety.
[0122] In one embodiment, the invention provides a method of
detecting a substance that is specifically bound by a binding
moiety, comprising contacting the device of claim 16 with a
composition known or suspected to contain the substance, and
detecting a signal from the device, wherein the signal changes as a
function of the amount of the substance present in the composition.
In one embodiment, the composition is a biological sample or an
environmental sample.
[0123] In one aspect, the invention provides a method of
identifying an agent that specifically binds a target compound,
comprising contacting a minicell displaying the target compound
with a library of compounds, and identifying an agent in the
library that binds the target compound. In one embodiment, the
library of compounds is a protein library. In one embodiment, the
protein library is selected from the group consisting of a phage
display library, a phagemid display library, a baculovirus library,
a yeast display library, and a ribosomal display library. In one
embodiment, the library of compounds is selected from the group
consisting of a library of aptamers, a library of synthetic
peptides and a library of small molecules.
[0124] In one embodiment, the target compound is a target
polypeptide. In one embodiment, the minicell comprises an
expression construct comprising expression sequences operably
linked to an ORF encoding the target polypeptide. In one
embodiment, the target polypeptide is a membrane protein. In one
embodiment, the membrane protein is a receptor or a channel
protein. In one embodiment, the membrane protein is an enzyme. In
one embodiment, the target compound is a membrane fusion protein,
the membrane fusion protein comprising a first polypeptide, wherein
the first polypeptide comprises at least one transmembrane domain
or at least one membrane anchoring domain; and a second
polypeptide, wherein the second polypeptide comprises amino acid
sequences derived from a target polypeptide. In one embodiment, the
method further comprises comparing the activity of the target
compound in the presence of the agent to the activity of the target
compound in the absence of the agent.
[0125] In one embodiment, the activity of the target compound is an
enzyme activity. In one embodiment, the activity of the target
compound is a binding activity. In one embodiment, the invention
further comprises comparing the binding of the agent to the target
compound to the binding of a known ligand of the target compound.
In one embodiment, a competition assay is used for the
comparing.
[0126] In one aspect, the invention provides a device comprising
microchips operatively associated with a biosensor comprising a set
of minicells in a prearranged pattern, wherein the each of the
microchips comprise or contact a minicell, wherein each of the
minicell displays a different target compound, and wherein binding
of a ligand to a target compound results in an increased or
decreased signal. In one embodiment, the invention provides a
method of identifying an agent that specifically binds a target
compound, comprising contacting the device with a library of
compounds, and detecting a signal from the device, wherein the
signal changes as a function of the binding of an agent to the
target compound. In one embodiment, the invention provides a method
of identifying an agent that specifically blocks the binding of a
target compound to its ligand, comprising contacting the device
with a library of compounds, and detecting a signal from the
device, wherein the signal changes as a function of the binding of
an agent to the target compound.
[0127] In one aspect, the invention provides a method of making a
antibody that specifically binds a protein domain, wherein the
domain is in its native conformation, wherein the domain is
contained within a protein displayed on a minicell, comprising
contacting the minicell with a cell, wherein the cell is competent
for producing antibodies to an antigen contacted with the cell, in
order to generate an immunogenic response in which the cell
produces the antibody.
[0128] In one embodiment, the protein displayed on a minicell is a
membrane protein. In one embodiment, the membrane protein is a
receptor or a channel protein. In one embodiment, the domain is
found within the second polypeptide of a membrane fusion protein,
wherein the membrane fusion protein comprises a first polypeptide,
wherein the first polypeptide comprises at least one transmembrane
domain or at least one membrane anchoring domain. In one
embodiment, the contacting occurs in vivo. In one embodiment, the
antibody is a polyclonal antibody or a monoclonal antibody. In one
embodiment, the contacting occurs in an animal that comprises an
adjuvant.
[0129] In one aspect, the invention provides the method of making
an antibody derivative that specifically binds a protein domain,
wherein the domain is in its native conformation, wherein the
domain is displayed on a minicell, comprising contacting the
minicell with a protein library, and identifying an antibody
derivative from the protein library that specifically binds the
protein domain. In one embodiment, the protein library is selected
from the group consisting of a phage display library, a phagemid
display library, and a ribosomal display library.
[0130] In one aspect, the invention provides a method of making an
antibody or antibody derivative that specifically binds an epitope,
wherein the epitope is selected from the group consisting of (i) an
epitope composed of amino acids found within a membrane protein,
(ii) an epitope present in an interface between a membrane protein
and a membrane component, (iii) an epitope present in an interface
between a membrane protein and one or more other proteins and (iv)
an epitope in a fusion protein, the fusion protein comprising a
first polypeptide, the first polypeptide comprising at least one
transmembrane domain or at least one membrane anchoring domain, and
a second polypeptide, the second polypeptide comprising the
epitope; comprising contacting a minicell displaying the epitope
with a protein library, or to a cell, wherein the cell is competent
for producing antibodies to an antigen contacted with the cell, in
order to generate an immunogenic response in which the cell
produces the antibody.
[0131] In one embodiment, the cell is contacted in vivo. In various
embodiments, the antibody is a polyclonal antibody or a monoclonal
antibody. In one embodiment, the protein library is contacted in
vitro. In one embodiment, the protein library is selected from the
group consisting of a phage display library, a phagemid display
library, and a ribosomal display library.
[0132] In one aspect, the invention provides a method of
determining the rate of transfer of nucleic acid from a minicell to
a cell, comprising (a) contacting the cell to the minicell, wherein
the minicell comprises the nucleic acid, for a measured period of
time; (b) separating minicells from the cells; (c) measuring the
amount of nucleic acid in the cells,wherein the amount of nucleic
acid in the cells over the set period of time is the rate of
transfer of a nucleic acid from a minicell.
[0133] In one aspect, the invention provides a method of
determining the amount of a nucleic acid transferred to a cell from
a minicell, comprising (a) contacting the cell to the minicell,
wherein the minicell comprises an expression element having
eukaryotic expression sequences operably linked to an ORF encoding
a detectable polypeptide, wherein the minicell displays a binding
moiety, and wherein the binding moiety binds an epitope of the
cell; and (b) detecting a signal from the detectable polypeptide,
wherein a change in the signal corresponds to an increase in the
amount of a nucleic acid transferred to a cell.
[0134] In one embodiment, the cell is a eukaryotic cell. By way of
non-limiting example, a eukaryotic cell can be a plant cell, a
fungal cell, a unicellular eukaryote, an animal cell, a mammalian
cell, a rat cell, a mouse cell, a primate cell or a human cell.
[0135] In one embodiment, the binding moiety is an antibody or
antibody derivative. In one embodiment, the binding moiety is a
single-chain antibody. In one embodiment, the binding moiety is an
aptamer. In one embodiment, the binding moiety is an organic
compound. In one embodiment, the detectable polypeptide is a
fluorescent polypeptide.
[0136] In one aspect, the invention provides a method of detecting
the expression of an expression element in a cell, comprising (a)
contacting the cell to a minicell, wherein the minicell comprises
an expression element having cellular expression sequences operably
linked to an ORF encoding a detectable polypeptide, wherein the
minicell displays a binding moiety, and wherein the binding moiety
binds an epitope of the cell; (b) incubating the cell and the
minicell for a period of time effective for transfer of nucleic
acid from the minicell to the cell; and (c) detecting a signal from
the detectable polypeptide, wherein an increase in the signal
corresponds to an increase in the expression of the expression
element.
[0137] In one embodiment, the cell is a eukaryotic cell and the
expression sequences are eukaryotic expression sequences. In one
embodiment, the eukaryotic cell is a mammalian cell. In one
embodiment, the binding moiety is an antibody or antibody
derivative. In one embodiment, the binding moiety is a single-chain
antibody. In one embodiment, the binding moiety is an aptamer. In
one embodiment, the binding moiety is an organic compound.
[0138] In a related aspect, the invention provides methods of
detecting the transfer of a fusion protein from the cytosol to an
organelle of a eukaryotic cell, comprising (a) contacting the cell
to a minicell, wherein (i) the minicell comprises an expression
element having eukaryotic expression sequences operably linked to
an ORF encoding a fusion protein, wherein the fusion protein
comprises a first polypeptide that comprises organellar delivery
sequences, and a second polypeptide that comprises a detectable
polypeptide; and (ii) the minicell displays a binding moiety that
binds an epitope of the cell, or an epitope of an organelle; (b)
incubating the cell and the minicell for a period of time effective
for transfer of nucleic acid from the minicell to the cell and
production of the fusion protein; and (c) detecting a signal from
the detectable polypeptide, wherein a change in the signal
corresponds to an increase in the amount of the fusion protein
transferred to the organelle.
[0139] In one aspect, the invention provides a minicell comprising
at least one nucleic acid, wherein the minicell displays a binding
moiety directed to a target compound, wherein the binding moiety is
selected from the group consisting of (i) a eukaryotic membrane
protein; (ii) an archeabacterial membrane protein; (iii) an
organellar membrane protein; and (iv) a fusion protein, the fusion
protein comprising a first polypeptide, the first polypeptide
comprising at least one transmembrane domain or at least one
membrane anchoring domain; and a second polypeptide, wherein the
second polypeptide is not derived from a eubacterial protein and is
neither a His tag nor a glutathione-S-transferase polypeptide, and
wherein the polypeptide comprises a binding moiety.
[0140] In one embodiment, the nucleic acid comprises an expression
construct comprising expression sequences operably linked to an ORF
encoding a protein selected from the group consisting of (i) the
eukaryotic membrane protein, (ii) the archeabacterial membrane
protein, (iii) the organellar membrane protein; and (iv) the fusion
protein.
[0141] In one embodiment, the nucleic acid comprises an expression
construct comprising expression sequences operably linked to an
ORF, wherein the ORF encodes a therapeutic polypeptide. In one
embodiment, the therapeutic polypeptide is a membrane polypeptide.
In one embodiment, the therapeutic polypeptide is a soluble
polypeptide. In one embodiment, the soluble polypeptide comprises a
cellular secretion sequence. In one embodiment, the expression
sequences are inducible and/or repressible.
[0142] In one embodiment, the expression sequences are induced
and/or derepressed when the binding moiety displayed by the
minicell binds to its target compound. In one embodiment, the
nucleic acid comprises an expression construct comprising
expression sequences operably linked to an ORF, wherein the ORF
encodes a polypeptide having an amino acid sequence that
facilitates cellular transfer of a biologically active compound
contained within or displayed by the minicell. In one embodiment,
the membrane of the minicell comprises a system for transferring a
molecule from the interior of a minicell into the cytoplasm of the
cell. In one embodiment, the system for transferring a molecule
from the interior of a minicell into the cytoplasm of the cell is a
Type III secretion system.
[0143] In one aspect, the invention provides a method of
introducing a nucleic acid into a cell, comprising contacting the
cell with a minicell that comprises the nucleic acid, wherein the
minicell displays a binding moiety, wherein the binding moiety is
selected from the group consisting of (i) a eukaryotic membrane
protein; (ii) an archeabacterial membrane protein; (iii) an
organellar membrane protein; and (iv) a fusion protein, the fusion
protein comprising a first polypeptide, the first polypeptide
comprising at least one transmembrane domain or at least one
membrane anchoring domain; and a second polypeptide, wherein the
second polypeptide is not derived from a eubacterial protein and is
neither a His tag nor a glutathione-S-transferase polypeptide, and
wherein the polypeptide comprises a binding moiety; and wherein the
binding moiety binds an epitope of the cell.
[0144] In one embodiment, the nucleic acid comprises an expression
construct comprising expression sequences operably linked to an ORF
encoding a protein selected from the group consisting of (i) the
eukaryotic membrane protein, (ii) the archeabacterial membrane
protein, (iii) the organellar membrane protein; and (iv) a fusion
protein.
[0145] In one embodiment, the nucleic acid comprises an expression
construct comprising expression sequences operably linked to an
ORF, wherein the ORF encodes a therapeutic polypeptide. In one
embodiment, the expression sequences are inducible and/or
derepressible. In one embodiment, the expression sequences are
induced or derepressed when the binding moiety displayed by the
minicell binds its target compound. In one embodiment, the
expression sequences are induced or derepressed by a
transactivation or transrepression event. In one embodiment, the
nucleic acid comprises an expression construct comprising
expression sequences operably linked to an ORF, wherein the ORF
encodes a polypeptide having an amino acid sequence that
facilitates cellular transfer of a biologically active compound
contained within or displayed by the minicell.
[0146] In one aspect, the invention provides a minicell comprising
a nucleic acid, wherein the nucleic acid comprises eukaryotic
expression sequences and eubacterial expression sequences, each of
which is independently operably linked to an ORF.
[0147] In one embodiment, the minicell displays a binding moiety.
In one embodiment, the eubacterial expression sequences are induced
and/or derepressed when the binding moiety is in contact with a
target cell. In one embodiment, the eukaryotic expression sequences
are induced and/or derepressed when the nucleic acid is in the
cytoplasm of a eukaryotic cell. In one embodiment, the protein
encoded by the ORF comprises eubacterial or eukaryotic secretion
sequences.
[0148] In one aspect, the invention provides a minicell comprising
a first and second nucleic acid, wherein the first nucleic acid
comprises eukaryotic expression sequences operably linked to a
first ORF, and a second nucleic acid, wherein the second nucleic
acid comprises eubacterial expression sequences operably linked to
a second ORF.
[0149] In one embodiment, the minicell displays a binding moiety.
In one embodiment, the eubacterial expression sequences are induced
and/or derepressed when the binding moiety is in contact with a
target cell. In one embodiment, the eukaryotic expression sequences
are induced and/or derepressed when the nucleic acid is in the
cytoplasm of a eukaryotic cell. In one embodiment, the protein
encoded by the first ORF comprises eukaryotic secretion sequences
and/or the protein encoded by the second ORF comprises eubacterial
secretion sequences.
[0150] In one aspect, the invention provides a method of
introducing into and expressing a nucleic acid in an organism,
comprising contacting a minicell to a cell of the organism, wherein
the minicell comprises the nucleic acid.
[0151] In one embodiment, the minicell displays a binding moiety.
In one embodiment, the nucleic acid comprises a eukaryotic
expression construct, wherein the eukaryotic expression construct
comprises eukaryotic expression sequences operably linked to an
ORF. In one embodiment, the ORF encodes a protein selected from the
group consisting of a membrane protein, a soluble protein and a
protein comprising eukaryotic secretion signal sequences. In one
embodiment, the nucleic acid comprises a eubacterial expression
construct, wherein the eubacterial expression construct comprises
eubacterial expression sequences operably linked to an ORF. In one
embodiment, the minicell displays a binding moiety, wherein the
eubacterial expression sequences are induced and/or derepressed
when the binding moiety is in contact with a target cell. In one
embodiment, the protein encoded by the ORF comprises eubacterial
secretion sequences. In one aspect, the invention provides a
minicell comprising a crystal of a membrane protein. In one
embodiment, the minicell is a eubacterial minicell, a poroplast, a
spheroplast or a protoplast. In one embodiment, the membrane
protein is a receptor. In one embodiment, the receptor is a
G-protein coupled receptor. In one embodiment, the crystal is
displayed.
[0152] In a related aspect, the invention provides a minicell
membrane preparation comprising a crystal of a membrane
protein.
[0153] In one embodiment, the membrane protein is a fusion protein,
the fusion protein comprising a first polypeptide, the first
polypeptide comprising at least one transmembrane domain or at
least one membrane anchoring domain, and a second polypeptide. In
one embodiment, the crystal is a crystal of the second polypeptide.
In one embodiment, the crystal is displayed.
[0154] In one aspect, the invention provides a method of
determining the three-dimensional structure of a membrane protein,
comprising preparing a crystal of the membrane protein in a
minicell, and determining the three-dimensional structure of the
crystal.
[0155] In one aspect, the invention provides a method for
identifying ligand-interacting atoms in a defined three-dimensional
structure of a target protein, comprising (a) preparing one or more
variant proteins of a target protein having a known or predicted
three-dimensional structure, wherein the target protein binds a
preselected ligand; (b) expressing and displaying a variant protein
in a minicell; and (c) determining if a minicell displaying the
variant protein binds the preselected ligand with increased or
decreased affinity as compared to the binding of the preselected
ligand to the target protein.
[0156] In one embodiment, the ligand is a protein that forms a
multimer with the target protein, and the ligand interacting atoms
are atoms in the defined three-dimensional structure are atoms that
are involved in protein-protein interactions. In one embodiment,
the ligand is a compound that induces a conformational change in
the target protein, and the defined three-dimensional structure is
the site of the conformational change. In one embodiment, the
method for identifying ligands of a target protein, further
comprising identifying the chemical differences in the variant
proteins as compared to the target protein. In one embodiment, the
invention further comprises mapping the chemical differences onto
the defined three-dimensional structure, and correlating the effect
of the chemical differences on the defined three-dimensional
structure. In one embodiment, the target protein is a wild-type
protein. In one aspect, the invention provides a minicell library,
comprising two or more minicells, wherein each minicell comprises a
different exogenous protein. In one embodiment, the minicell is a
eubacterial minicell, a poroplast, a spheroplast or a protoplast.
In one embodiment, the exogenous protein is a displayed protein. In
one embodiment, the exogenous protein is a membrane protein. In one
embodiment, the membrane protein is a receptor. In one embodiment,
the protein is a soluble protein that is contained within or
secreted from the minicell. In one embodiment, minicells within the
library comprise an expression element that comprises expression
sequences operably linked to a nucleic acid having an ORF that
encodes the exogenous protein. In one embodiment, the nucleic acid
has been mutagenized; the mutagenesis can be site-directed or
random. In one embodiment, an active site of the exogenous protein
has a known or predicted three-dimensional structure, and the a
portion of the ORF encoding the active site has been mutagenized.
In one embodiment, each of the minicells comprises an exogenous
protein that is a variant of a protein having a known or predicted
three-dimensional structure.
[0157] In one aspect, the invention provides a minicell library,
comprising two or more minicells, wherein each minicell comprises a
different fusion protein, each of the fusion protein comprising a
first polypeptide that is a constant polypeptide, wherein the
constant polypeptide comprises at least one transmembrane domain or
at least one membrane anchoring domain, and a second polypeptide,
wherein the second polypeptide is a variable amino acid sequence
that is different in each fusion proteins. In one embodiment,
minicells within the library comprise an expression element that
comprises expression sequences operably linked to a nucleic acid
having an ORF that encodes the fusion protein. In one embodiment,
the second polypeptide of the fusion protein is encoded by a
nucleic acid that has been cloned. In one embodiment, each of the
second polypeptide of each of the fusion proteins comprises a
variant of an amino acid sequence from a protein having a known or
predicted three-dimensional structure.
[0158] In one aspect, the invention provides a minicell library,
comprising two or more minicells, wherein each minicell comprises a
constant protein that is present in each minicell and a variable
protein that differs from minicell to minicell. In one embodiment,
one of the constant and variable proteins is a receptor, and the
other of the constant and variable proteins is a co-receptor. In
one embodiment, each of the constant and variable proteins is
different from each other and is a factor in a signal transduction
pathway. In one embodiment, one of the constant and variable
proteins is a G-protein, and the other of the constant and variable
proteins is a G-protein coupled receptor.
[0159] In one embodiment, one of the constant and variable proteins
comprises a first transrepression domain, and the other of the
constant and variable comprises a second transrepression domain,
wherein the transrepression domains limit or block expression of a
reporter gene when the constant and variable proteins associate
with each other.
[0160] In one embodiment, one of the constant and variable proteins
comprises a first transactivation domain, and the other of the
constant and variable comprises a second transactivation domain,
wherein the transactivation domains stimulate expression of a
reporter gene when the constant and variable proteins associate
with each other.
[0161] In one aspect, the invention provides a method of
identifying a nucleic acid that encodes a protein that binds to or
chemically alters a preselected ligand, comprising (a) separately
contacting the ligand with individual members of a minicell
library, wherein minicells in the library comprise expression
elements, wherein the expression elements comprise DNA inserts,
wherein an ORF in the DNA insert is operably linked to expression
sequences, in order to generate a series of reaction mixes, each
reaction mix comprising a different member of the minicell library;
(b) incubating the reaction mixes, thereby allowing a protein that
binds to or chemically alters the preselected ligand to bind or
chemically alter the preselected ligand; (c) detecting a change in
a signal from reaction mixes in which the ligand has been bound or
chemically altered; (d) preparing DNA from reaction mixes in which
the ligand has been bound or chemically altered; wherein the DNA is
a nucleic acid that encodes a protein that binds to or chemically
alters the preselected ligand.
[0162] In one embodiment, the minicell is a eubacterial minicell, a
poroplast, a spheroplast or a protoplast. In one embodiment, the
preselected ligand is a biologically active compound. In one
embodiment, the preselected ligand is a therapeutic drug. In one
embodiment, a protein that binds or chemically alters the
preselected ligand is a target protein for compounds that are
therapeutic for a disease that is treated by administering the drug
to an organism in need thereof. In one embodiment, the preselected
ligand is detectably labeled, the mincell comprises a detectable
compound, and/or a chemically altered derivative of the protein is
detectably labeled.
[0163] In one aspect, the invention provides a method of
determining the amino acid sequence of a protein that binds or
chemically alters a preselected ligand, comprising: (a) contacting
the ligand with a minicell library, wherein minicells in the
library comprise expression elements, wherein the expression
elements comprise DNA inserts, wherein an ORF in the DNA insert is
operably linked to expression sequences; (b) incubating the mixture
of ligand and minicells, under conditions which allow complexes
comprising ligands and minicells to form and/or chemical reactions
to occur; (c) isolating or identifying the complexes from the
ligand and the mixture of ligand and minicells; (d) preparing DNA
from an expression element found in one or more of the complexes,
or in a minicell thereof; (e) determining the nucleotide sequence
of the ORF in the DNA; and (f) generating an amino sequence by in
silico translation, wherein the amino acid sequence is or is
derived from a protein that binds or chemically alters a
preselected ligand.
[0164] In one embodiment, the minicell is a eubacterial minicell, a
poroplast, a spheroplast or a protoplast. In one embodiment, the
DNA is prepared by isolating DNA from the complexes, or in a
minicell thereof. In one embodiment, the DNA is prepared by
amplifying DNA from the complexes, or in a minicell thereof. In one
embodiment, the protein is a fusion protein. In one embodiment, the
protein is a membrane or a soluble protein. In one embodiment, the
protein comprises secretion sequences. In one embodiment, the
preselected ligand is a biologically active compound. In one
embodiment, the preselected ligand is a therapeutic drug. In one
embodiment, the preselected ligand is a therapeutic drug, and the
protein that binds the preselected ligand is a target protein for
compounds that are therapeutic for a disease that is treated by
administering the drug to an organism in need thereof.
[0165] In one aspect, the invention provides a method of
identifying a nucleic acid that encodes a protein that inhibits or
blocks an agent from binding to or chemically altering a
preselected ligand, comprising: (a) separately contacting the
ligand with individual members of a minicell library, wherein
minicells in the library comprise expression elements, wherein the
expression elements comprise DNA inserts, wherein an ORF in the DNA
insert is operably linked to expression sequences, in order to
generate a series of reaction mixes, each reaction mix comprising a
different member of the minicell library; (b) incubating the
reaction mixes, thereby allowing a protein that binds to or
chemically alters the preselected ligand to bind or chemically
alter the preselected ligand; (c) detecting a change in a signal
from reaction mixes in which the ligand has been bound or
chemically altered; (d) preparing DNA from reaction mixes in which
the change in signal ligand has been bound or chemically altered;
wherein the DNA is a nucleic acid that encodes a protein that
inhibits or blocks the agent from binding to or chemically altering
the preselected ligand.
[0166] In one embodiment, the minicell is a eubacterial minicell, a
poroplast, a spheroplast or a protoplast. In one embodiment, the
DNA has a nucleotide sequence that encodes the amino acid sequence
of the protein that inhibits or blocks the agent from binding to or
chemically altering the preselected ligand. In one embodiment, a
protein that binds or chemically alters the preselected ligand is a
target protein for compounds that are therapeutic for a disease
that is treated by administering the drug to an organism in need
thereof.
[0167] In one aspect, the invention provides a method of
identifying an agent that effects the activity of a protein,
comprising contacting a library of two or more candidate agents
with a minicell comprising the protein or a polypeptide derived
from the protein, assaying the effect of candidate agents on the
activity of the protein, and identifying agents that effect the
activity of the protein.
[0168] In one embodiment, the protein or the polypeptide derived
from the protein is displayed on the surface of the minicell. In
one embodiment, the protein is a membrane protein. In one
embodiment, the membrane protein is selected from the group
consisting of a receptor, a channel protein and an enzyme. In one
embodiment, the activity of a protein is a binding activity or an
enzymatic activity. In one embodiment, the library of compounds is
a protein library. In one embodiment, the protein library is
selected from the group consisting of a phage display library, a
phagemid display library, and a ribosomal display library. In one
embodiment, the library of compounds is a library of aptamers. In
one embodiment, the library of compounds is a library of small
molecules.
[0169] In one aspect, the invention provides a method of
identifying an agent that effects the activity of a protein domain
containing a library of two or more candidate agents with a
minicell displaying a membrane fusion protein, the fusion protein
comprising a first polypeptide, the first polypeptide comprising at
least one transmembrane domain or at least one membrane anchoring
domain, and a second polypeptide, wherein the second polypeptide
comprises the protein domain.
[0170] In one aspect, the invention provides a method of
identifying undesirable side-effects of a biologically active
compound that occur as a result of binding of the compound to a
protein, wherein binding a compound to the protein is known to
result in undesirable side effects, comprising contacting a
minicell that comprises the protein to the biologically active
compound. In one embodiment, the invention provides comprises
characterizing the binding of the biologically active compound to
the protein. In one embodiment, the invention provides comprises
characterizing the effect of the biologically active compound on
the activity of the protein.
[0171] In one aspect, the invention provides a method for
identifying an agent that effects the interaction of a first
signaling protein with a second signaling protein, comprising (a)
contacting a library of compounds with a minicell, wherein the
minicell comprises: (i) a first protein comprising the first
signaling protein and a first trans-acting regulatory domain; (ii)
a second protein comprising the second signaling protein and a
second trans-acting regulatory domain; and (iii) a reporter gene,
the expression of which is modulated by the interaction between the
first trans-acting regulatory domain and the second trans-acting
regulatory domain; and (b) detecting the gene product of the
reporter gene.
[0172] In one embodiment, the trans-acting regulatory domains are
transactivation domains. In one embodiment, the trans-acting
regulatory domains are transrepression domains.
[0173] In one embodiment, the reporter gene is induced by the
interaction of the first trans-acting regulatory domain and the
second trans-acting regulatory domain. In one embodiment, the agent
that effects the interaction of the first signaling protein with
the second signaling protein is an agent that causes or promotes
the interaction. In one embodiment, the reporter gene is repressed
by the interaction of the first trans-acting regulatory domain and
the second trans-acting regulatory domain. In one embodiment, the
agent that effects the interaction of the first signaling protein
with the second signaling protein is an agent that inhibits or
blocks the interaction.
[0174] In one embodiment, the first signaling protein is a GPCR. In
one embodiment, the GPCR is an Edg receptor or a ScAMPER.
[0175] In one embodiment, the second signalling protein is a
G-protein. In related embodiments, G-protein is selected from the
group consisting of G-alpha-i, G-alpha-s, G-alpha-q, G-alpha-12/13
and Go. In one embodiment, the library of compounds is a protein
library. In one embodiment, the protein library is selected from
the group consisting of a phage display library, a phagemid display
library, and a ribosomal display library. In one embodiment, the
library of compounds is a library of aptamers. In one embodiment,
the library of compounds is a library of small molecules.
[0176] In one aspect, the invention provides a method for
identifying an agent that effects the interaction of a first
signaling protein with a second signaling protein, comprising
contacting a library of two or more candidate agents with a
minicell, wherein the minicell comprises (a) a first fusion protein
comprising the first signaling protein and a first detectable
domain; and (b) a second fusion protein comprising the second
signaling protein and a second detectable domain, wherein a signal
is generated when the first and second signaling proteins are in
close proximity to each other, and detecting the signal.
[0177] In one embodiment, the signal is fluorescence. In one
embodiment, the first detectable domain and the second detectable
domain are fluorescent and the signal is generated by FRET. In one
embodiment, the first and second detectable domains are
independently selected from the group consisting of a green
fluorescent protein, a blue-shifted green fluorescent protein, a
cyan-shifted green fluorescent protein; a red-shifted green
fluorescent protein; a yellow-shifted green fluorescent protein,
and a red fluorescent protein, wherein the first fluorescent domain
and the second fluorescent domain are not identical.
[0178] In one aspect, the invention provides a method of
bioremediation, the method comprising contacting a composition that
comprises an undesirable substance with a minicell, wherein the
minicell alters the chemical structure and/or binds the undesirable
substance.
[0179] In one aspect, the invention provides a method of
bioremediation, the method comprising contacting a composition that
comprises an undesirable substance with a minicell, wherein the
mincell comprises an agent that alters the chemical structure of
the undesirable substance. In one embodiment, the agent that alters
the chemical structure of the undesirable substance is an inorganic
catalyst. In one embodiment, the agent that alters the chemical
structure of the undesirable substance is an enzyme. In one
embodiment, the enzyme is a soluble protein contained within the
minicell. In one embodiment, the enzyme is a secreted protein. In
one embodiment, the enzyme is a membrane protein. In one
embodiment, the membrane enzyme is selected from the group
consisting of a cytochrome P450, an oxidoreductase, a transferase,
a hydrolase, a lyase, an isomerase, a ligase and a synthetase. In
one embodiment, the agent that alters the chemical structure of the
undesirable substance is a fusion protein comprising a first
polypeptide that comprises a transmembrane domain or at least one
membrane-anchoring domain, and a second polypeptide, wherein the
second polypeptide is an enzyme moiety.
[0180] In one aspect, the invention provides a method of
bioremediation, the method comprising contacting a composition that
comprises an undesirable substance with a minicell, wherein the
mincell comprises an agent that binds an undesirable substance. In
one embodiment, the undesirable substance binds to and is
internalized by the minicell or is otherwise inactivated by
selective absorption. In one embodiment, the agent that binds the
undesirable substance is a secreted soluble protein. In one
embodiment, the secreted protein is a transport accessory protein.
In one embodiment, the agent that binds the undesirable substance
is a membrane protein. In one embodiment, the undesirable substance
is selected from the group consisting of a toxin, a pollutant and a
pathogen. In one embodiment, the agent that binds the undesirable
substance is a fusion protein comprising a first polypeptide that
comprises a transmembrane domain or at least one membrane-anchoring
domain, and a second polypeptide, wherein the second polypeptide is
a binding moiety. In one embodiment, wherein the binding moiety is
selected from the group consisting of an antibody, an antibody
derivative, the active site of a non-enzymatically active mutant
enzyme, a single-chain antibody and an aptamer.
[0181] In one aspect, the invention provides a minicell-producing
parent cell, wherein the parent cell comprises one or more of the
following (a) an expression element that comprises a gene operably
linked to expression sequences that are inducible and/or
repressible, wherein induction or repression of the gene regulates
the copy number of an episomal expression construct; (b) a mutation
in an endogenous gene, wherein the mutation regulates the copy
number of an episomal expression construct; (c) an expression
element that comprises a gene operably linked to expression
sequences that are inducible and/or repressible, wherein induction
or repression of the gene causes or enhances the production of
minicells; and (d) a mutation in an endogenous gene, wherein the
mutation causes or enhances minicell production.
[0182] In one embodiment, the invention comprises an episomal
expression construct. In one embodiment, the invention further
comprises a chromosomal expression construct. In one embodiment,
the expression sequences of the expression construct are inducible
and/or repressible. In one embodiment, the minicell-producing
parent cell comprises a biologically active compound. In one
embodiment, the gene that causes or enhances the production of
minicells has a gene product that is involved in or regulates DNA
replication, cellular division, cellular partitioning, septation,
transcription, translation, or protein folding.
[0183] In one aspect, the invention provides a minicell-producing
parent cell, wherein the parent cell comprises an expression
construct, wherein the expression construct comprises expression
sequences operably linked to an ORF that encodes a protein, and a
regulatory expression element, wherein the regulatory expression
element comprises expression sequences operably linked to a
regulatory gene that encodes a factor that regulates the expression
of the ORF. In one embodiment, the expression sequences of the
expression construct are inducible and/or repressible. In one
embodiment, the expression sequences of the regulatory expression
construct are inducible and/or repressible. In one embodiment, one
or more of the expression element or the regulatory expression
element is located on a chromosome of the parent cell. In one
embodiment, one or more of the expression element or the regulatory
expression element is located on an episomal expression construct.
In one embodiment, both of the expression element and the
regulatory expression element are located on an episomal expression
construct, and one or both of the expression element and the
regulatory expression element segregates into minicells produced
from the parent cell. In one embodiment, the minicell-producing
parent cell comprises a biologically active compound. In one
embodiment, the biologically active compound segregates into
minicells produced from the parent cell. In one embodiment, the ORF
encodes a membrane protein or a soluble protein. In one embodiment,
the protein comprises secretion sequences. In one embodiment, the
gene product of the gene regulates the expression of the ORF. In
one embodiment, the gene product is a transcription factor. In one
embodiment, the gene product is a RNA polymerase. In one
embodiment, the parent cell is MC-T7.
[0184] In one aspect, the invention provides a minicell comprising
a biologically active compound, wherein the minicell displays a
binding moiety, wherein the minicell selectively absorbs and/or
internalizes an undesirable compound, and the minicell is a
poroplast, spheroplast or protoplast. In one embodiment, the
binding moiety is selected from the group consisting of an
antibody, an antibody derivative, a receptor and an active site of
a non-catalytic derivative of an enzyme. In one embodiment, the
binding moiety is a single-chain antibody. In one embodiment, the
binding moiety is directed to a ligand selected from the group
consisting of an epitope displayed on a pathogen, an epitope
displayed on an infected cell and an epitope displayed on a
hyperproliferative cell. In one embodiment, the biologically active
compound is selected from the group consisting of a radioisotope, a
polypeptide, a nucleic acid and a small molecule. In one
embodiment, a ligand binds to and is internalized by the minicell
or is otherwise inactivated by selective absorption. In one
embodiment, the invention provides a pharmaceutical composition
comprising the minicell. In one aspect, the invention provides a
method of reducing the free concentration of a substance in a
composition, wherein the substance displays a ligand specifically
recognized by a binding moiety, comprising contacting the
composition with a minicell that displays the binding moiety,
wherein the binding moiety binds the substance, thereby reducing
the free concentration of the substance in the composition. In one
embodiment, the substance is selected from the group consisting of
a nucleic acid, a lipid, a polypeptide, a radioactive compound, an
ion and a small molecule. In one embodiment, the binding moiety is
selected from the group consisting of an antibody, an antibody
derivative, a channel protein and a receptor.
[0185] In one embodiment, the composition is present in an
environment including but not limited to water, air or soil. In one
embodiment, the composition is a biological sample from an
organism, including but not limited to blood, serum, plasma, urine,
saliva, a biopsy sample, feces, tissue and a skin patch. In one
embodiment, the substance binds to and is internalized by the
minicell or is otherwise inactivated by selective absorption. In
one embodiment, the biological sample is returned to the organism
after being contacting to the minicell.
[0186] For a better understanding of the present invention,
reference is made to the accompanying detailed description and its
scope will be pointed out in the appended claims. All references
cited herein are hereby incorporated by reference.
BRIEF DESCRIPTION OF THE DRAWINGS
[0187] FIG. 1 is a Western blot in which Edg-1-6xHis and
Edg-3-6xHis proteins expressed in minicells produced from MC-T7
cells.
[0188] FIG. 2 shows induction of MalE(L)-NTR in isolated
minicells.
ABBREVIATIONS AND DEFINITIONS
[0189] For brevity's sake, the single-letter amino acid
abbreviations are used in some instances herein. Table 1 describes
the correspondence between the 1- and 3-letter amino acid
abbreviations.
1TABLE 1 THREE- AND ONE-LETTER ABBREVIATIONS FOR AMINO ACIDS
Three-letter One-letter Amino acid abbreviation symbol Alanine Ala
A Arginine Arg R Asparagine Asn N Aspartic Acid Asp D Cysteine Cys
C Glutamine Gln Q Glutamic acid Glu E Glycine Gly G Histidine His H
Isoleucine Ile I Leucine Leu L Lysine Lys K Methionine Met M
Phenylalanine Phe F Proline Pro P Serine Ser S Threonine Thr T
Tryptophan Trp W Tyrosine Tyr Y Valine Val V
[0190] A "conjugatable compound" or "attachable compound" is
capable of being attached to another compound. The terms
"conjugated to" and "cross-linked with" indicate that the
conjugatable compound is in the state of being attached to another
compound.A "conjugate" is the compound formed by the attachment of
a conjugatable compound or conjugatable moiety to another
compound.
[0191] "Culturing" signifies incubating a cell or organism under
conditions wherein the cell or organism can carry out some, if not
all, biological processes. For example, a cell that is cultured may
be growing or reproducing, or it may be non-viable but still
capable of carrying out biological and/or biochemical processes
such as replication, transcription, translation, etc.
[0192] An agent is said to have been "purified" if its
concentration is increased, and/or the concentration of one or more
undesirable contaminants is decreased, in a composition relative to
the composition from which the agent has been purified.
Purification thus encompasses enrichment of an agent in a
composition and/or isolation of an agent therefrom.
[0193] A "solid support" is any solid or semisolid composition to
which an agent can be attached or contained within. Common forms of
solid support include, but are not limited to, plates, tubes, and
beads, all of which could be made of glass or another suitable
material, e.g., polystyrene, nylon, cellulose acetate,
nitrocellulose, and other polymers. Semisolids and gels that
minicells are suspended within are also considered to be solid
supports. A solid support can be in the form of a dipstick,
flow-through device, or other suitable configuration.
[0194] A "mutation" is a change in the nucleotide sequence of a
gene relative to the sequence of the "wild-type" gene. Reference
wild-type eubacterial strains are those that have been cultured in
vitro by scientists for decades; for example, a wild-type strain of
Escherichia coli iss E. coli K-12. Mutations include, but are not
limited to, point mutations, deletions, insertions and
translocations.
[0195] A "trans-acting regulatory domain" is a regulatory part of a
protein that is expressed from a gene that is not adjacent to the
site of regulatory effect. Trans-acting domains can activate or
stimulate (transactivate), or limit or block (transrepress) the
gene in question.
[0196] A "reporter gene" refers to a gene that is operably linked
to expression sequences, and which expresses a gene product,
typically a detectable polypeptide, the production and detection of
which is used as a measure of the robustness and/or control of
expression.
[0197] A "detectable compound" or "detectable moiety" produces a
signal that can be detected by spectroscopic, photochemical,
biochemical, immunochemical, electromagnetic, radiochemical, or
chemical means such as fluorescence, chemifluoresence, or
chemiluminescence, or any other appropriate means. A "radioactive
compound" or "radioactive composition" has more than the natural
(environmental) amount of one or more radioisotopes.
[0198] By "displayed" it is meant that a portion of the membrane
protein is present on the surface of a cell or minicell, and is
thus in contact with the external environment of the cell or
minicell. The external, displayed portion of a membrane protein is
an "extracellular domain" or a "displayed domain." A membrane
protein may have more than one displayed domain, and a minicell of
the invention may display more than one membrane protein.
[0199] A "domain" or "protein domain" is a region of a molecule or
structure that shares common physical and/or chemical features.
Non-limiting examples of protein domains include hydrophobic
transmembrane or peripheral membrane binding regions, globular
enzymatic or receptor regions, and/or nucleic acid binding
domains.
[0200] A "transmembrane domain" spans a membrane, a "membrane
anchoring domain" is positioned within, but does not traverse, a
membrane. An "extracellular" or "displayed" domain is present on
the exterior of a cell, or minicell, and is thus in contact with
the external environment of the cell or minicell.
[0201] A "eukaryote" is as the term is used in the art. A eukaryote
may, by way of non-limiting example, be a fungus, a unicellular
eukaryote, a plant or an animal. An animal may be a mammal, such as
a rat, a mouse, a rabbit, a dog, a cat, a horse, a cow, a pig, a
simian or a human.
[0202] A "eukaryotic membrane" is a membrane found in a eukaryote.
A eukaryotic membrane may, by way of non-limiting example, a
cytoplasmic membrane, a nuclear membrane, a nucleolar membrane, a
membrane of the endoplasmic reticulum (ER), a membrane of a Golgi
body, a membrane of a lysosome a membrane of a peroxisome, a
caveolar membrane, or an inner or outer membrane of a
mitochondrion, chloroplast or plastid.
[0203] The term "endogenous" refers to something that is normally
found in a cell as that cell exists in nature.
[0204] The term "exogenous" refers to something that is not
normally found in a cell as that cell exists in nature.
[0205] A "gene" comprises (a) nucleotide sequences that either (i)
act as a template for a nucleic acid gene product, or (ii) that
encode one or more open reading frames (ORFs); and (b) expression
sequences operably linked to (1) or (2). When a gene comprises an
ORF, it is a "structural gene."
[0206] By "immunogenic," it is meant that a compound elicits
production of antibodies or antibody derivatives and, additionally
or alternatively, a T-cell mediated response, directed to the
compound or a portion thereof. The compound is an "immunogen."
[0207] A "ligand" is a compound, composition or moiety that is
capable of specifically bound by a binding moiety, including
without limitation, a receptor and an antibody or antibody
derivative.
[0208] A "membrane protein" is a protein found in whole or in part
in a membrane. Typically, a membrane protein has (1) at least one
membrane anchoring domain, (2) at least one transmembrane domain,
or (3) at least one domain that interacts with a protein having (1)
or (2).
[0209] An "ORF" or "open reading frame" is a nucleotide sequence
that encodes an amino acid sequence of a known, predicted or
hypothetical polypeptide. An ORF is bounded on its 5' end by a
start codon (usually ATG) and on its 3' end by a stop codon (i.e.,
TAA or TGA). An ORF encoding a 10 amino acid sequence comprises 33
nucleotides (3 for each of 10 amino acids and 3 for a stop codon).
ORFs can encode amino acid sequences that comprise from 10, 25, 50,
125, 150, 175, 200, 250, 300, 350, 400, 450, 500, 600, 700, 800,
900 or more amino acids
[0210] The terms "Eubacteria" and "prokaryote" are used herein as
these terms are used by those in the art. The terms "eubacterial"
and "prokaryotic" encompasses Eubacteria, including both
gram-negative and gram-positive bacteria, prokaryotic viruses
(e.g., bacteriophage), and obligate intracellular parasites (e.g.,
Rickettsia, Chlamydia, etc.).
[0211] An "active site" is any portion or region of a molecule
required for, or that regulates, an activity of the molecule. In
the case of a protein, an active site can be a binding site for a
ligand or a substrate, an active site of enzyme, a site that
directs or undergoes conformational change in response to a signal,
or a site of post-translational modification of a protein.
[0212] In a poroplast, the eubacterial outer membrane (OM) and LPS
have been removed. In a spheroplast, portions of a disrupted
eubacterial OM and/or disrupted cell wall either may remain
associated with the inner membrane of the minicell, but the
membrane is nonetheless porous because the permeability of the
disrupted OM has been increased. A membrane is the to be
"disrupted" when the membrane's structure has been treated with an
agent, or incubated under conditions, that leads to the partial
degradation of the membrane, thereby increasing the permeability
thereof. In contrast, a membrane that has been "degraded" is
essentially, for the applicable intents and purposes, removed. In
preferred embodiments, irrespective of the condition of the OM and
cell wall, the eubacterial inner membrane is not disrupted, and
membrane proteins displayed on the inner membrane are accessible to
compounds that are brought into contact with the minicell,
poroplast, spheroplast, protoplast or cellular poroplast, as the
case may be.
[0213] Host cells (and/or minicells) harboring an expression
construct are components of expression systems.
[0214] An "expression vector" is an artificial nucleic acid
molecule into which an exogenous ORF encoding a protein, or a
template of a bioactive nucleic acid can be inserted in such a
manner so as to be operably linked to appropriate expression
sequences that direct the expression of the exogenous gene.
Preferred expression vectors are episomal vectors that can
replicate independently of chromosomal replication.
[0215] By the term "operably linked" it is meant that the gene
products encoded by the non-vector nucleic acid sequences are
produced from an expression element in vivo.
[0216] The term "gene product" refers to either a nucleic acid (the
product of transcription, reverse transcription, or replication) or
a polypeptide (the product of translation) that is produced using
the non-vector nucleic acid sequences as a template.
[0217] An "expression construct" is an expression vector into which
a nucleotide sequence of interest has been inserted in a manner so
as to be positioned to be operably linked to the expression
sequences present in the expression vector. Preferred expression
constructs are episomal.
[0218] An "expression element" is a nucleic acid having nucleotide
sequences that are present in an expression construct but not its
cognate expression vector. That is, an expression element for a
polypeptide is a nucleic acid that comprises an ORF operably linked
to appropriate expression sequences. An expression element can be
removed from its expression construct and placed in other
expression vectors or into chromosomal DNA.
[0219] "Expression sequences" are nucleic acid sequences that bind
factors necessary for the expression of genes that have been
inserted into an expression vector. An example of an expression
sequence is a promoter, a sequence that binds RNA polymerase, which
is the enzyme that produces RNA molecules using DNA as a template.
An example of an expression sequence that is both inducible and
repressible is L-arabinose operon (araC). See Schleif R. Regulation
of the L-arabinose operon of Escherichia coli. Trends Genet. Dec;
16, 2000 (12):559-65.
[0220] In the present disclosure, "a nucleic acid" or "the nucleic
acid" refers to a specific nucleic acid molecule. In contrast, the
term "nucleic acid" refers to any collection of diverse nucleic
acid molecules, and thus signifies that any number of different
types of nucleic acids are present. By way of non-limiting example,
a nucleic acid may be a DNA, a dsRNA, a tRNA (including a rare
codon usage tRNA), an mRNA, a ribosomal RNA (rRNA), a peptide
nucleic acid (PNA), a DNA:RNA hybrid, an antisense oligonucleotide,
a ribozyme, or an aptamer.
DETAILED DESCRIPTION OF THE INVENTION
[0221] The invention described herein is drawn to compositions and
methods for the production of achromosomal archeabacterial,
eubacterial and anucleate eukaryotic cells that are used for
diagnostic and therapeutic applications, for drug discovery, and as
research tools.
[0222] The general advantage of minicells over cell-based
expression systems (e.g., eucaryotic cells or bacterial expression
systems) is that one may express heterologous membrane bound
proteins or over express endogenous membrane bound proteins ,
cytoplasmic or secreted soluble proteins,or small molecules on the
cytoplasmic or extracellular surfaces of the minicells that would
otherwise be toxic to live cells. Minicells are also advantageous
for proteins that require a particular lipid environment for proper
functioning because it is very manipulatable in nature. Other
advantages include the stability of the minicells due to the lack
of toxicity, the high level of expression that can be achieved in
the minicell, and the efficient flexible nature of the minicell
expression system. Such minicells could be used for in vivo
targeting or for selective absorption (i.e., molecular "sponges")
and that these molecules can be expressed and "displayed" at high
levels. Minicells can also be used to display proteins for low,
medium, high, and ultra high throughput screening, crystal
formation for structure determination, and for in vitro research
use only applications such as transfection. Minicells expressing
proteins or small molecules, radioisotopes, image-enhancing
reagents can be used for in vivo diagnostics and for in vitro
diagnostic and assay platforms. Also, soluble and/or membrane
associated signaling cascade elements may be reconstituted in
minicells producing encapsulated divices to follow extracellular
stimulation events using cytoplasmic reporter events, e.g.
transactivation resulting from dimerization of dimerization
dependant transcriptional activation or repression of said
reporter.
[0223] Regarding protein expression, minicells can be engineered to
express one or more recombinant proteins in order to produce more
protein per surface area of the particle (at least 10.times.more
protein per unit surface area of protein). The proteins or small
molecules that are "displayed" on the minicell surfaces can have
therapeutic, discovery or diagnostic benefit either when injected
into a patient or used in a selective absorption mode during
dialysis. In vitro assays include drug screening and discovery,
structural proteomics, and other functional proteomics
applications. Proteins that are normally soluble can be tethered to
membrane anchoring domains or membrane proteins can be expressed
for the purpose of displaying these proteins on the surfaces of the
minicell particle in therapeutic, discovery, and diagnostic modes.
The types of proteins that can be displayed include but are not
limited to receptors (e.g., GPCRs, sphingolipid receptors,
neurotransmitter receptors, sensory receptors, growth factor
receptors, hormone receptors, chemokine receptors, cytokine
receptors, immunological receptors, and complement receptors, FC
receptors), channels (e.g., potassium channels, sodium channels,
calcium channels.), pores (e.g., nuclear pore proteins, water
channels), ion and other pumps (e.g., calcium pumps, proton pumps),
exchangers (e.g., sodium/potassium exchangers, sodium/hydrogen
exchangers, potassium/hydrogen exchangers), electron transport
proteins (e.g., cytochrome oxidase), enzymes and kinases (e.g.,
protein kinases, ATPases, GTPases, phosphatases, proteases.),
structural/linker proteins (e.g., Caveolins, clathrin), adapter
proteins (e.g., TRAD, TRAP, FAN), chemotactic/adhesion proteins
(e.g., ICAMI1, selecting, CD34, VCAM-1, LFA-1, VLA-1), and
chimeric/fussion proteins (e.g., proteins in which a normally
soluble protein is attached to a transmembrane region of another
protein). As a non-limiting example, the small molecules that can
be tethered and displayed on the surfaces of the minicells can be
carbohydrates (e.g., monosaccharides), bioactive lipids (e.g.,
lysosphingolipids, PAF, lysophospholipids), drugs (e.g.,
antibiotics, ion channel activators/inhibitors, ligands for
receptors and/or enzymes), nucleic acids (e.g., synthetic
oligonucleotides), fluorophores, metals, or inorganic and organic
small molecules typically found in combinatorial chemistry
libraries. Minicells may either contain (encapsulate) or display on
their surfaces radionuclides or image-enhancing reagents both of
which could be used for therapeutic and/or diagnostic benefit in
vivo or for in vitro assays and diagnostic platforms.
[0224] For in vivo therapeutic uses, minicells can express proteins
and/or display small molecules on their surfaces that would either
promote an immune response and passage through the RES system
(e.g., to eliminate the minicell and its target quickly), or to
evade the RES (e.g., to increase the bioavailability of the
minicell). Toxicity is reduced or eliminated because the
therapeutic agent is not excreted or processed by the liver and
thus does not damage the kidneys or liver, because the
minicell-based therapeutic is not activated until entry into the
target cell (e.g., in the case of cancer therapeutics or gene
therapy). Minicells are of the appropriate size (from about 0.005,
0.1, 0.15 or 0.2 micrometers to about 0.25, 0.3, 0.35, 0.4, 0.45 or
0.5 micrometers) to facilitate deep penetration into the lungs in
the cases where administration of the minicell-based therapeutic or
diagnostic is via an inhalant (Strong, A. A., et al. 1987. An
aerosol generator system for inhalation delivery of pharmacological
agents. Med. Instrum. 21:189-194). This is due to the fact that
minicells can be aerosolized. Without being limited to the
following examples, inhalant therapeutic uses of minicells could be
applied to the treatment of anaphylactic shock, viral infection,
inflammatory reactions, gene therapy for cystic fibrosis, treatment
of lung cancers, and fetal distress syndrome.
[0225] Minicells can also display expressed proteins that are
enzymes that may have therapeutic and/or diagnostic uses. The
enzymes that are displayed may be soluble enzymes that are
expressed as fusion proteins with a transmembrane domain of another
protein. Display of such enzymes could be used for in vitro assays
or for therapeutic benefit.
[0226] Gene therapy applications afforded by minicells generally
involve the ability of minicells to deliver DNA to target cells
(either for replacement therapy, modification of cell function or
to kill cells). Expression plasmids can be delivered to target
cells that would encode proteins that could be cytoplasmic or could
have intracellular signal sequences that would target the protein
to a particular organelle (e.g., mitochondria, nuclei, endoplasmic
reticulum, etc.). In the case where minicells are engulfed by the
target cell, the minicells themselves could have these
intracellular targeting sequences expressed on their surfaces so
that the minicells could be `delivered` to intracellular
targets.
[0227] Minicells used for the following therapeutic, discovery, and
diagnostic applications can be prepared as described in this
application and then stored and/or packaged by a variety of ways,
including but not limited to lyophilization, freezing, mixing with
preservatives (e.g., antioxidants, glycerol), or otherwise stored
and packaged in a fashion similar to methods used for liposome and
proteoliposome formulations.
[0228] The small size of minicells (from about 0.005, 0.1, 0.15 or
0.2 micrometers to about 0.25, 0.3, 0.35, 0.4, 0.45 or 0.5
micrometers) makes them suitable for many in vitro diagnostic
platforms, including the non-limiting examples of lateral flow,
ELISA, HTS, especially those applications requiring microspheres or
nanospheres that display many target proteins or other molecules.
The use of protoplast or poroplast minicells may be especially
useful in this regard. Assay techniques are dependent on cell or
particle size, protein (or molecule to be tested) amount displayed
on the surface of the cell or particle, and the sensitivity of the
assay being measured. In current whole-cell systems, the expression
of the protein of interest is limiting, resulting in the higher
cell number requirement to satisfy the sensitivity of most assays.
However, the relatively large size of cells prevents the
incorporation of large numbers of cells in these assays, e.g. 96,
384, and smaller well formats. In contrast, minicells, protoplasts,
and poroplasts are smaller in size and can be manipulated to
express high levels of the preselected protein, and can be
incorporated into small well assay formats.
I. Types of Minicells
[0229] Minicells are derivatives of cells that lack chromosomal DNA
and which are sometimes referred to as anucleate cells. Because
eubacterial and achreabacterial cells, unlike eukaryotic cells, do
not have a nucleus (a distinct organelle that contains
chromosomes), these non-eukaryotic minicells are more accurately
described as being "without chromosomes" or "achromosomal," as
opposed to "anucleate." Nonetheless, those skilled in the art often
use the term "anucleate" when referring to bacterial minicells in
addition to other minicells. Accordingly, in the present
disclosure, the term "minicells" encompasses derivatives of
eubacterial cells that lack a chromosome; derivatives of
archeabacterial cells that lack their chromosome(s) (Laurence et
al., Nucleoid Structure and Partition in Methanococcus jannaschii:
An Archaeon With Multiple Copies of the Chromosome, Genetics
152:1315-1323, 1999); and anucleate derivatives of eukaryotic
cells. It is understood, however, that some of the relevant art may
use the terms "anucleate minicells" or "anucleate cells" loosely to
refer to any of the preceeding types of minicells.
[0230] I.A. Eubacterial Minicells
[0231] One type of minicell is a eubacterial minicell. For reviews
of eubacterial cell cycle and division processes, see Rothfield et
al., Bacterial Cell Division, Annu. Rev. Genet., 33:423-48, 1999;
Jacobs et al., Bacterial cell division: A moveable feast, Proc.
Natl. Acad. Sci. USA, 96:5891-5893, May, 1999; Koch, The
Bacterium's Way for Safe Enlargement and Division, Appl. and Envir.
Microb., Vol. 66, No. 9, pp. 3657-3663; Bouche and Pichoff, On the
birth and fate of bacterial division sites. Mol Microbiol, 1998.
29: 19-26; Khachatourians et al., Cell growth and division in
Escherichia coli: a common genetic control involved in cell
division and minicell formation. J Bacteriol, 1973. 116: 226-229;
Cooper, The Escherichia coli cell cycle. Res Microbiol, 1990. 141:
17-29; and Danachie and Robinson, "Cell Division: Parameter Values
and the Process," in: Escherichia Coli and Salmonella Typhimurium:
Cellular and Molecular Biology, Neidhardt, Frederick C., Editor in
Chief, American Society for Microbiology, Washington, D.C., 1987,
Volume 2, pages 1578-1592, and references cited therein; and
Lutkenhaus et al., "Cell Division," Chapter 101 in: Escherichia
coli and Salmonella typhimurium: Cellular and Molecular Biology,
2.sup.nd Ed., Neidhardt, Frederick C., Editor in Chief, American
Society for Microbiology, Washington, D.C., 1996, Volume 2, pages
1615-1626, and references cited therein. When DNA replication
and/or chromosomal partitioning is altered, membrane-bounded
vesicles "pinch off" from parent cells before transfer of
chromosomal DNA is completed. As a result of this type of
dysfunctional division, minicells are produced which contain an
intact outer membrane, inner membrane, cell wall, and all of the
cytoplasm components but do not contain chromosomal DNA. See Table
2.
[0232] I.B. Eukaryotic Minicells
[0233] The term "eukaryote" is defined as is used in the art, and
includes any organism classified as Eucarya that are usually
classified into four kingdoms: plants, animals, fungi and protists.
The first three of these correspond to phylogenetically coherent
groups. However, the eucaryotic protists do not form a group, but
rather are comprised of many phylogenetically disparate groups
(including slime molds, multiple groups of algae, and many distinct
groups of protozoa). See, e.g., Olsen, G.,
http://www.bact.wisc.edu/microtextbook/. A type of animal of
particular interest is a mammal, including, by way of non-limiting
example a rat, a mouse, a rabbit, a dog, a cat, a horse, a cow, a
pig, a simian and a human.
[0234] Chromosomeless eukaryotic minicells (i.e., anucleate cells)
are within the scope of the invention. Platelets are a non-limiting
example of eukaryotic minicells. Platelets are anucleate cells with
little or no capacity for de novo protein synthesis. The tight
regulation of protein synthesis in platelets (Smith et al.,
Platelets and stroke, Vase Med 4:165-72, 1999) may allow for the
over-production of exogenous proteins and, at the same time,
under-production of endogenous proteins. Thrombin-activated
expression elements such as those that are associated with Bcl-3
(Weyrich et al., Signal-dependent translation of a regulatory
protein, Bcl-3, in activated human platelets, Cel Biology
95:5556-5561, 1998) may be used to modulate the expresion of
exogneous genes in platelets.
[0235] As another non-limiting example, eukaryotic minicells are
generated from tumor cell lines (Gyongyossy-Issa and
Khachatourians, Tumour minicells: single, large vesicles released
from cultured mastocytoma cells (1985) Tissue Cell 17:801-809;
Melton, Cell fusion-induced mouse neuroblastomas HPRT revertants
with variant enzyme and elevated HPRT protein levels (1981) Somatic
Cell Genet 7: 331-344).
[0236] Yeast cells are used to generate fungal minicells. See,
e.g., Lee et al., Ibd1p, a possible spindle pole body associated
protein, regulates nuclear division and bud separation in
Saccharomyces cerevisiae, Biochim Biophys Acta 3:239-253, 1999;
Kopecka et al., A method of isolating anucleated yeast protoplasts
unable to synthesize the glucan fibrillar component of the wall J
Gen Microbiol 81:111-120, 1974; and Yoo et al., Fission yeast Hrpl,
a chromodomain ATPase, is required for proper chromosome
segregation and its overexpression interferes with chromatin
condensation, Nucl Acids Res 28:2004-2011, 2000. Cell division in
yeast is reviewed by Gould and Simanis, The control of septum
formation in fission yeast, Genes & Dev 11:2939-51, 1997).
[0237] I.C. Archeabacterial Minicells
[0238] The term "archeabacterium" is defined as is used in the art
and includes extreme thermophiles and other Archaea. Woese, C. R.,
L. Magrum. G. Fox. 1978. Archeabacteria. Journal of Molecular
Evolution. 11:245-252. Three types of Archeabacteria are
halophiles, thermophiles and methanogens. By physiological
definition, the Archaea (informally, archaes) are single-cell
extreme thermophiles (including thermoacidophiles), sulfate
reducers, methanogens, and extreme halophiles. The thermophilic
members of the Archaea include the most thermophilic organisms
cultivated in the laboratory. The aerobic thermophiles are also
acidophilic; they oxidize sulfur in their environment to sulfuric
acid. The extreme halophiles are aerobic or microaerophilic and
include the most salt tolerant organisms known. The
sulfate-reducing Archaea reduce sulfate to sulfide in extreme
environment. Methanogens are strict anaerobes, yet they gave rise
to at least two separate aerobic groups: the halophiles and a
thermoacidophilic lineage (Olsen, G.,
http://www.bact.wisc.edu/microtextbook/). Non-limiting examples of
halophiles include Halobacterium cutirubrum and Halogerax
mediterranei. Non-limiting examples of methanogens include
Methanococcus voltae; Methanococcus vanniela; Methanobacterium
thermoautotrophicum; Methanococcus voltae; Methanothermus fervidus;
and Methanosarcina barkeri. Non-limiting examples of thermophiles
include Azotobacter vinelandii; Thermoplasma acidophilum;
Pyrococcus horikoshii; Pyrococcusfuriosus; and Crenarchaeota
(extremely thermophilic archaebacteria) species such as Sulfolobus
solfataricus and Sulfolobus acidocaldarius.
[0239] Archeabacterial minicells are within the scope of the
invention. Archeabacteria have homologs of eubacterial minicell
genes and proteins, such as the MinD polypeptide from Pyrococcus
furiosus (Hayashi et al., EMBO J 2001 20:1819-28, Structural and
functional studies of MinD ATPase: implications for the molecular
recognition of the bacterial cell division apparatus). It is thus
possible to create Archeabacterial minicells by methods such as, by
way of non-limiting example, overexpressing the product of a min
gene isolated from a prokaryote or an archeabacterium; or by
disrupting expression of a min gene in an archeabacterium of
interest by, e.g., the introduction of mutations thereof or
antisense molecules thereto. See, e.g., Laurence et al., Nucleoid
Structure and Partition in Methanococcus jannaschii: An Archaeon
With Multiple Copies of the Chromosome, Genetics 152:1315-1323,
1999.
[0240] In one aspect, the invention is drawn to archael minicells.
By physiological definition, the Archaea (informally, archaes) are
single-cell extreme thermophiles (including thermoacidophiles),
sulfate reducers, methanogens, and extreme halophiles. The
thermophilic members of the Archaea include the most thermophilic
organisms cultivated in the laboratory. The aerobic thermophiles
are also acidophilic; they oxidize sulfur in their environment to
sulfuric acid. The extreme halophiles are aerobic or
microaerophilic and include the most salt tolerant organisms known.
The sulfate-reducing Archaea reduce sulfate to sulfide in extreme
environment. Methanogens are strict anaerobes, yet they gave rise
to at least two separate aerobic groups: the halophiles and a
thermoacidophilic lineage (Olsen, G ., http://www. bact.
wisc.edu/microtextbook/).
[0241] I.D. Minicells Produced from Diverse Organisms
[0242] There are genes that can be disrupted to cause minicell
production that are conserved among the three Kingdoms. For
example, SMC (structural maintenance of chormosomes) proteins are
conserved among prokaryotes, archeabacteria and eukaryotes (Hirano,
SMC-mediated chromosome and mechanics: a conserved scheme from
bacteria to vertebrates?, Genes and Dev. 13:11-19, 1999; Holmes et
al., Closing the ring: Links between SMC proteins and chromosome
partitioning, condensation, and supercoiling, PNAS 97:1322-1324,
2000; Michiko and Hiranol, EMBO J 17:7139-7148, 1998, ATP-dependent
aggregation of single-stranded DNA by a bacterial SMC homodimer,
1998). Mutations in B. subtilis smc genes result in the production
of minicells (Britton et al., Characterization of a eubacterial smc
protein involved in chromosome partitioning, Genes and Dev.
12:1254-1259, 1998; Moriya et al., A Bacillus subuilis
gene-encoding protein homologous to eukaryotic SMC motor protein is
necessary for chromosome partition Mol Microbiol 29:179-87, 1998).
Disruption of smc genes in various cells is predicted to result in
minicell production therefrom.
[0243] As another example, mutations in the yeast genes encoding
TRF topoisomerases result in the production of minicells, and a
human homolog of yeast TRF genes has been stated to exist (Castano
et al., A novel family of TRF (DNA topoisomerase I-related
function) genes required for proper nuclear segregation, Nucleic
Acids Res 24:2404-10, 1996). Mutations in a yeast chromodomain
ATPase, Hrpl, result in abnormal chromosomal segregation; (Yoo et
al., "Fission yeast Hrp1, a chromogomain ATPase, is required for
proper chromosome segregation and its overexpression interferes
with chromatin condensation," Nuc. Acids Res. 28:2004-2001).
Disruption of TRF and/or Hrp1 function is predicted to cause
minicell production in various cells. Genes involved in septum
formation in fission yeast (see, e.g., Gould et al., "The control
of septum formation in fission yeast," Genes and Dev. 11:2939-2951,
1997) can be used in like fashion.
[0244] As another example, mutations in the divIVA gene of Bacillus
subtilis results in minicell production (Table 2). When expressed
in E. coli or the yeast Schizosaccharomyces pombe, a B. subtilis
DivIVA-GFP protein is targeted to cell division sites therein, even
though clear homologs of DivIVA do not seem to exist in E. coli or
S. pombe (David et al., Promiscuous targeting of Bacillus subtilis
cell division protein DivIVA to division sites in Escherichia coli
and fission yeast, EMBO J 19:2719-2727, 2000.) Over- or
under-expression of B. subtilis DivIVA or a homolog thereof may be
used to reduce minicell production in a variety of cells.
II. Production of Minicells
[0245] Eubacterial minicells are produced by parent cells having a
mutation in, and/or overexpressing, or under expressing a gene
involved in cell division and/or chromosomal partitioning, or from
parent cells that have been exposed to certain conditions, that
result in abberant fission of bacterial cells and/or partitioning
in abnormal chromosomal segregation during cellular fission
(division). The term "parent cells" or "parental cells" refers to
the cells from which minicells are produced. Minicells, most of
which lack chromosomal DNA (Mulder et al., The Escherichia coli
minB mutation resembles gyrB in Defective nucleoid segregation and
decreased negative supercoiling of plasmids. Mol Gen Genet, 1990,
221: 87-93), are generally, but need not be, smaller than their
parent cells. Typically, minicells produced from E. coli cells are
generally spherical in shape and are about 0.1 to about 0.3 um in
diameter, whereas whole E. coli cells are about from about 1 to
about 3 um in diameter and from about about 2 to about 10 um in
length. Micrographs of E. coli cells and minicells that have been
stained with DAPI (4:6-diamidino-z-phenylindole), a compound that
binds to DNA, show that the minicells do not stain while the parent
E. coli are brightly stained. Such micrographs demonstrate the lack
of chromosomal DNA in minicells. (Mulder et al., Mol. Gen. Genet.
221:87-93, 1990).
[0246] As shown in Table 2, minicells are produced by several
different mechanisms such as, by way of non-limiting example, the
over expression of genes involved in chromosomal replication and
partitioning, mutations in such genes, and exposure to various
environmental conditions. "Overexpression" refers to the expression
of a polypeptide or protein encoded by a DNA introduced into a host
cell, wherein the polypeptide or protein is either not normally
present in the host cell, or wherein the polypeptide or protein is
present in the host cell at a higher level than that normally
expressed from the endogenous gene encoding the polypeptide or
protein. For example, in E. coli cells that overexpress the gene
product FtsZ (The FtsZ gene encodes a protein that is involved in
regulation of divisions; see Cook and Rothfield, Early stages in
development of the Escherichia coli cell-division site. Mol
Microbiol, 1994. 14: p. 485-495; and Lutkenhaus, Regulation of cell
division in E. coli. Trends Genet, 1990. 6: p. 22-25), there is an
increase in the formation of minicells (Begg et al., Roles of FtsA
and FtsZ in the activation of division sites. J. Bacteriology,
1997. 180: 881-884). Minicells are also produced by E. coli cells
having a mutation in one or more genes of the min locus, which is a
group of genes that encode proteins that are involved in cell
division (de Boer et al., Central role for the Escherichia coli
minC gene product in two different cell division-inhibition
systems. Proc. Natl. Acad. Sci. USA, 1990. 87: 1129-33; Akerlund et
al., Cell division in Escherichia coli minB mutants. Mol Microbiol,
1992. 6: 2073-2083).
[0247] Prokaryotes that have been shown to produce minicells
include species of Escherichia, Shigella, Bacillus, Lactobacillus,
and Campylobacter. Bacterial minicell-producing species of
particular interest are E. coli and Bacillus subtilis. E. coli is
amenable to manipulation by a variety of molecular genetic methods,
with a variety of well-characterized expression systems, including
many episomal expression systems, factors and elements useful in
the present invention. B. subtilis, also amenable to genetic
manipulation using episomal expression elements, is an important
industrial organism involved in the production of many of the
world's industrial enzymes (proteases, amylases, etc.), which it
efficiently produces and secretes.
[0248] In the case of other eubacterial species, homologs of E.
coli or B. subilis genes that cause minicell production therein are
known or can be identified and characterized as is known in the
art. For example, the min regions of the chromosome of Strepococcus
pneumoniae and Neisseria gonorrhoeae have been characterized
(Massidda et al., Unconventional organization of the division and
cell wall gene cluster of Streptococcus pneumoniae, Microbiology
144:3069-78, 1998; and Ramirez-Arcos et al., Microbiology
147:225-237, 2001 and Szeto et al., Journal of Bacteria
183(21):6253, 2001, respectively). Those skilled in the art are
able to isolate minicell producing (min) mutants, or prepare
compounds inhibitory to genes that induce a minicell production
(e.g., antisense to min transcripts).
2TABLE 2 Eubacterial Strains, Mutations and Conditions that Promote
Minicell Formation Species Strain Notes References Campylobacter
jejuni may occur naturally late Brock et al., 1987 in growth cycle
Bacillus subtilis Mutations in divIVB locus Barak et al., 1999
(inc. minC, minD ripX mutations Sciochetti et al., 1999; Lemon et
al., 2001 smc mutations Moriya et al., 1998; Britton et al., 1998
oriC deletions Moriya et al., 1997; Hassan et al., 1997 prfA
mutations Pederson and Setlow, 2001 Mutations in divIVA locus Cha
et al., 1997 B.s. 168 ts initiation mutation TsB143 Sargent, 1975
Bacillus cereus WSBC Induced by exposure to Maier et al., 1999
10030 long-chain polyphosphate Shigella flexneri (2a) MC-1 Gemski
et al., 1980 S. dysenteriae (1) MC-V Gemski et al., 1980
Lactobacillus spp. Variant minicell-producing Pidoux et al., 1990
strains isolated from grains Neisseria gonorrhoeae deletion or
overepression Ramirez-Arcos et al., 2001; of min homologues Szeto
et al., 2001 Escherichia coli MinA mutations Frazer et al., 1975;
Cohen et al. 1976 MinB mutations and deletions Adler et al., 1967;
Davie et al., 1984; Schaumberg et al.; 1983; Jaffe et al., 1988;
Akerlund et al., 1992 CA8000 cya, crp mutations Kumar et al.; 1979
MukA1 mutation Hiraga et al., 1996 MukE, mukF mutations Yamanaka et
al., 1996 hns mutation Kaidow et al., 1995 DS410 Heighway et al.,
1989 .chi.1972, .chi.1776 and .chi.2076 Curtiss, 1980 P678-54
Temperature-sensitive cell Adler et al. 1967; division mutations
Allen et al., 1972; Hollenberg et al., 1976 Induced by
overexpression De Boer et al., 1988 of minB protein Induced by
overexpression of Pichoff et al., 1995 minE protein or derivatives
Induced by oveproduction of Ward et al., 1985 ftsZ gene Induced by
overexpression Wang et al., 1991 of sdiA gene Induced by
overexpression of min Ramirez-Arcos et al., 2001; genes from
Neisseria gonorrhoeae Szeto et al., 2001 Induced by exposure to
EGTA Wachi et al., 1999 Legionella Pneumophila Induced by exposure
to ampicillin Elliot et al., 1985
Citations for Table 2
[0249] Adler et al., Proc. Natl. Acad. Sci. 57:321-326 (1967)
[0250] Akerlund et al., Mol. Microbiol. 6:2073-2083 (1992)
[0251] Allen et al., Biochem. Biophys. Res. Communi. 47:1074-1079
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[0252] Barak et al., J. Bacteriol. 180:5237-5333 (1998)
[0253] Britton et al., Genes Dev. 12:1254-9 (1998)
[0254] Brock et al., Can. J. Microbiol. 33:465-470 (1987)
[0255] Cha et al., J. Bacteriol. 179:1671-1683 (1997)
[0256] Cohen et al., Genetics 56:550-551 (1967)
[0257] Curtiss, Roy III, U.S. Pat. No. 4,190,495; Issued February
26, 1980
[0258] Davie et al., J. Bacteriol. 170:2106-2112 (1988)
[0259] Elliott et al., J. Med. Microbiol, 19:383-390 (1985)
[0260] Frazer et al., Curr. Top. Immunol. 69:1-84 (1975)
[0261] Gemski et al., Infect. Immun. 30:297-302 (1980)
[0262] Hassan et al., J. Bacteriol. 179:2494-502 (1997)
[0263] Heighway et al., Nucleic Acids Res. 17:6893-6901 (1989)
[0264] Hiraga et al., J. Bacteriol. 177:3589-3592 (1995)
[0265] Hollenberg et al., Gene 1:33-47 (1976)
[0266] Kumar et al., Mol. Gen. Genet. 176:449-450 (1979)
[0267] Lemon et al., Proc. Natl. Acad. Sci. USA 98:212-7 (2001)
[0268] Maier et al., Appl. Environ. Microbiol. 65:3942-3949
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[0269] Moriya et al., DNA Res 4:115-26 (1997)
[0270] Moriya et al., Mol. Microbiol. 29:179-87 (1998)
[0271] Markiewicz et al., FEMS Microbiol. Lett. 70:119-123
(1992)
[0272] Pederson and Setlow, J. Bacteriol. 182:1650-8 (2001)
[0273] Pichoff et al., Mol. Microbiol. 18:321-329 (1995)
[0274] Pidoux et al., J. App. Bacteriol. 69:311-320 (1990)
[0275] Ramirez-Arcos et al. Microbiol. 147:225-237 (2001)
[0276] Sargent M. G., J. Bacteriol. 123:1218-1234 (1975)
[0277] Sciochetti et al., J. Bacteriol. 181:6053-62 (1999)
[0278] Schaumberg et al., J. Bacteriol. 153:1063-1065 (1983)
[0279] Szeto et al., Jour. of Bacter. 183 (21):6253 (2001)
[0280] Wachi et al., Biochimie 81:909-913 (1999)
[0281] Wang et al., Cell 42:941-949 (1985)
[0282] Yamanaka et al., Mol. Gen. Genet. 250:241-251 (1996)
[0283] II.A. Optimized Minicell Construction
[0284] Minicells are produced by several different eubacterial
strains and mechanisms including the overexpression of endogenous
or exogenous genes involved in cell division, chromosomal
replication and partitioning, mutations in such genes, and exposure
to various chemical and/or physical conditions. For example, in E.
coli cells that overexpress the gene product FtsZ (the ftsZ gene
encodes a protein that is involved in regulation of cell division;
see Cook and Rothfield, Early stages in development of the
Escherichia coli cell-division site. Mol Microbiol, 1994. 14: p.
485-495; and Lutkenhaus, Regulation of cell division in E. coli.
Trends Genet, 1990. 6: p. 22-25), there is an increase in the
formation of minicells (Begg et al., Roles of FtsA and FtsZ in the
activation of division sites. J. Bacteriology, 1997. 180: 881-884).
Minicells are also produced by E. coli cells having a mutation in
one or more genes of the min locus, which is a group of genes that
encode proteins that are involved in cell division (de Boer et al.,
Central role for the Escherichia coli minC gene product in two
different cell division-inhibition systems. Proc. Natl. Acad. Sci.
USA, 1990. 87: 1129-33; Akerlund et al., Cell division in
Escherichia coli minB mutants. Mol Microbiol, 1992. 6:
2073-2083).
[0285] Eubacterial cells that have been shown to produce minicells
include, but are not limited to species of Escherichia, Shigella,
Bacillus, Lactobacillus, Legionella and Campylobacter. Bacterial
minicell-producing species of particular interest are E. coli and
Bacillus subtilis. These organisms are amenable to manipulation by
a variety of molecular and genetic methods, with a variety of
well-characterized expression systems, including many episomal and
chromosomal expression systems, as well as other factors and
elements useful in the present invention.
[0286] The following sections describe genes that may be
manipulated so as to stimulate the production of minicells. The
invention may include any of these non-limiting examples for the
purpose of preparing minicells. Furthermore, these genes and gene
products and conditions, may be used in methodologies to identify
other gene(s), gene products, biological events, biochemical
events, or physiological events that induce or promote the
production of minicells. These methodologies include, but are not
limited to genetic selection, protein, nucleic acid, or
combinatorial chemical library screen, one- or two-hybrid analysis,
display selection technologies, e.g. phage or yeast display,
hybridization approaches, e.g. array technology, and other high- or
low-throughput approaches.
[0287] II.A. 1. Homologs
[0288] Homologs of these genes and gene products from other
organisms may also be used. As used herein, a "homolog" is defined
is a nucleic acid or protein having a nucleotide sequence or amino
acid sequence, respectively, that is "identical," "essentially
identical," "substantially identical," "homologous" or "similar"
(as described below) to a reference sequence which may, by way of
non-limiting example, be the sequence of an isolated nucleic acid
or protein, or a consensus sequence derived by comparison of two or
more related nucleic acids or proteins, or a group of isoforms of a
given nucleic acid or protein. Non-limiting examples of types of
isoforms include isoforms of differing molecular weight that result
from, e.g., alternate RNA splicing or proteolytic cleavage; and
isoforms having different post-translational modifications, such as
glycosylation; and the like.
[0289] Two sequences are said to be "identical" if the two
sequences, when aligned with each other, are exactly the same with
no gaps, substitutions, insertions or deletions.
[0290] Two sequences are said to be "essentially identical" if the
following criteria are met. Two amino acid sequences are
"essentially identical" if the two sequences, when aligned with
each other, are exactly the same with no gaps, insertions or
deletions, and the sequences have only conservative amino acid
substitutions. Conservative amino acid substitutions are as
described in Table 3.
3TABLE 3 CONSERVATIVE AMINO ACID SUBSTITUTIONS Type of Amino Groups
of Amino Acids that Are Conservative Acid Side Chain Substitutions
Relative to Each Other Short side chain Glycine, Alanine, Serine,
Threonine and Methionine Hydrophobic Leucine, Isoleucine and Valine
Polar Glutamine and Asparagine Acidic Glutamic Acid and Aspartic
Acid Basic Arginine, Lysine and Histidine Aromatic Phenylalanine,
Tryptophan and Tyrosine
[0291] Two nucleotide sequences are "essentially identical" if they
encode the identical or essentially identical amino acid sequence.
As is known in the art, due to the nature of the genetic code, some
amino acids are encoded by several different three base codons, and
these codons may thus be substituted for each other without
altering the amino acid at that position in an amino acid sequence.
In the genetic code, TTA, TTG, CTT, CTC, CTA and CTG encode Leu;
AGA, AGG, CGT, CGC, CGA and CGG encode Arg; GCT, GCC, GCA and GCG
encode Ala; GGT, GGC, GGA and GGG encode Gly; ACT, ACC, ACA and ACG
encode Thr; GTT, GTC, GTA and GTG encode Val; TCT, TCC, TCA and TCG
encode Ser; CCT, CCC, CCA and CCG encode Pro; ATA, ATC and ATA
encode IIe; GAA and GAG encode Glu; CAA and CAG encode Gln; GAT and
GAC encode Asp; AAT and AAC encode Asn; AGT and AGC encode Ser; TAT
and TAC encode Tyr; TGT and TGC encode Cys; AAA and AAG encode Lys;
CAT and CAC encode His; TTT and TTC encode Phe, TGG encodes Trp;
ATG encodes Met; and TGA, TAA and TAG are translation stop
codons.
[0292] Two amino acid sequences are "substantially identical" if,
when aligned, the two sequences are, (i) less than 30%, preferably
.ltoreq.20%, more preferably <15%, most preferably .ltoreq.10%,
of the identities of the amino acid residues vary between the two
sequences; (ii) the number of gaps between or insertions in,
deletions of and/or subsitutions of, is .ltoreq.10%, more
preferably <5%, more preferably .ltoreq.3%, most preferably
.ltoreq.1%, of the number of amino acid residues that occur over
the length of the shortest of two aligned sequences.
[0293] Two sequences are said to be "homologous" if any of the
following criteria are met. The term "homolog" includes without
limitation orthologs (homologs having genetic similarity as the
result of sharing a common ancestor and encoding proteins that have
the same function in different species) and paralog (similar to
orthologs, yet gene and protein similarity is the result of a gene
duplication).
[0294] One indication that nucleotide sequences are homologous is
if two nucleic acid molecules hybridize to each other under
stringent conditions. Stringent conditions are sequence dependent
and will be different in different circumstances. Generally,
stringent conditions are selected to be about 5.degree. C. lower
than the thermal melting point (Tm) for the specific sequence at a
defined ionic strength and pH. The Tm is the temperature (under
defined ionic strength and pH) at which 50% of the target sequence
hybridizes to a perfectly matched probe. Typically, stringent
conditions will be those in which the salt concentration is about
0.02 M at pH 7 and the temperature is at least about 60.degree.
C.
[0295] Another way by which it can be determined if two sequences
are homologous is by using an appropriate algorithm to determine if
the above-described criteria for substantially identical sequences
are met. Sequence comparisons between two (or more) polynucleotides
or polypeptides are typically performed by algorithms such as, for
example, the local homology algorithm of Smith and Waterman (Adv.
Appl. Math. 2:482, 1981); by the homology alignment algorithm of
Needleman and Wunsch (J. Mol. Biol. 48:443, 1970); by the search
for similarity method of Pearson and Lipman (Proc. Natl. Acad. Sci.
U.S.A. 85:2444, 1988); and by computerized implementations of these
algorithms (GAP, BESTFIT, FASTA, and TFASTA in the Wisconsin
Genetics Software Package, version 10.2 Genetics Computer Group
(GCG), 575 Science Dr., Madison, Wis.); BLASTP, BLASTN, and FASTA
(Altschul et al., J. Mol. Biol. 215:403-410, 1990); or by visual
inspection.
[0296] Optimal alignments are found by inserting gaps to maximize
the number of matches using the local homology algorithm of Smith
and Waterman (1981) Adv. Appl. Math. 2:482-489. "Gap" uses the
algorithm of Needleman and Wunsch (1970 J Mol. Biol. 48:443-453) to
find the alignment of two complete sequences that maximizes the
number of matches and minimizes the number of gaps. In such
algorithms, a "penalty" of about 3.0 to about 20 for each gap, and
no penalty for end gaps, is used.
[0297] Homologous proteins also include members of clusters of
orthologous groups of proteins (COGs), which are generated by
phylogenetic classification of proteins encoded in complete
genomes. To date, COGs have been delineated by comparing protein
sequences encoded in 43 complete genomes, representing 30 major
phylogenetic lineages. Each COG consists of individual proteins or
groups of paralogs from at least 3 lineages and thus corresponds to
an ancient conserved domain (see Tatusov et al., A genomic
perspective on protein families. Science, 278: 631-637, 1997;
Tatusov et al., The COG database: new developments in phylogenetic
classification of proteins from complete genomes, Nucleic Acids
Res. 29:22-28, 2001; Chervitz et al., Comparisn of the Complete
Sets of Worm and Yeast: Orthology and Divergence, Science
282:2022-2028, 1998; and http://www.ncbi.nlm.nih.gov/COG/).
[0298] The entirety of two sequences may be identical, essentially
identical, substantially identical, or homologous to one another,
or portions of such sequences may be identical or substantially
identical with sequences of similar length in other sequences. In
either case, such sequences are similar to each other. Typically,
stretches of identical or essentially within similar sequences have
a length of .gtoreq.12, preferably .gtoreq.24, more preferably
.gtoreq.48, and most preferably .gtoreq.96 residues.
[0299] II.A.2. Escherichia coli Genes
[0300] Exemplary genes and gene products from E. coli the
expression and/or sequence of which can be manipulated so as to
stimulate minicell production in E. coli or any other organism, as
can homologs thereof from any species, include without limitation,
the bolA gene (Aldea, M., et al. 1988. Identification, cloning, and
expression of bolA, an ftsZ-dependent morphogene of Escherichia
coli. J. Bacteriol. 170:5196-5176; Aldea, M., et al. 1990. Division
genes in Escherichia coli are expressed coordinately to cell septum
requirements by gearbox promoters. EMBO J. 9:3787-3794); the chpA
gene (Masuda, Y., et al. 1993. chpA and chpB, Escherichia coli
chromosomal homologs of the pem locus responsible for stable
maintenance of plasmid R100. J. Bacteriol. 175:6850-6856); the chpB
gene (Masuda, Y., et al. 1993. chpA and chpB, Escherichia coli
chromosomal homologs of the pem locus responsible for stable
maintenance of plasmid R100. J. Bacteriol. 175:6850-6856); the chpR
(chpAl) gene (Masuda, Y., et al. 1993. chpA and chpB, Escherichia
coli chromosomal homologs of the pem locus responsible for stable
maintenance of plasmid R100. J. Bacteriol. 175:6850-6856); the chpS
(chpBl)gene (Masuda, Y., et al. 1993. chpA and chpB, Escherichia
coli chromosomal homologs of the pem locus responsible for stable
maintenance of plasmid R100. J. Bacteriol. 175:6850-6856); the crg
gene (Redfield, R. J., and A. M. Campbell. 1987. Structurae of
cryptic lambda prophages. J. Mol. Biol. 198:393-404); the crp gene
(Kumar, S., et al. 1979. Control of minicell producing cell
division by cAMP-receptor protein complex in Escherichia coli. Mol.
Gen. Genet. 176:449-450); the cya gene (Kumar, S., et al. 1979.
Control of minicell producing cell division by cAMP-receptor
protein complex in Escherichia coli. Mol. Gen. Genet. 176:449-450);
the dicA gene (Labie, C., et al. 1989. Isolation and mapping of
Escherichia coli mutations conferring resistance to division
inhibition protein DicB. J. Bacteriol. 171:4315-4319); the dicB
gene (Labie, C., et al. 1989. Isolation and mapping of Escherichia
coli mutations conferring resistance to division inhibition protein
DicB. J. Bacteriol. 171:4315-4319; Labie, C., et al. 1990.
Minicell-forming mutants of Escherichia coli: suppression of both
DicB- and MinD-dependent division inhibition by inactivation of the
minC gene product. J. Bacteriol. 1990. 172:5852-5858); the dicC
gene (Bejar, S., et al. 1988. Cell division inhibition gene dicB is
regulated by a locus similar to lambdoid bacteriophage immunity
loci. Mol. Gen. Genet. 212:11-19); the dicF gene (Tetart, F., and
J. P. Bouche. 1992. Regulation of the expression of the cell-cycle
gene ftsZ by DicF antisense RNA. Division does not require a fixed
number of FtsZ molecules. Mol. Microbiol. 6:615-620); the dif gene
(Kuempel, P. L., et al. 1991. dif, a recA-independent recombination
site in the terminus region of the chromosome of Escherichia coli.
New Biol. 3:799-811); the dksA gene (Yamanaka, K., et al. 1994.
Cloning, sequencing, and characterization of multicopy suppressors
of a mukB mutation in Escherichia coli. Mol. Microbiol.
13:301-312); the dnaK gene (Paek, K. H., and G. C. Walker. 1987.
Escherichia coli dnaK null mutants are inviable at high
temperature. J. Bacteriol. 169:283-290); the dnaj gene (Hoffman, H.
J., et al. 1992. Activity of the Hsp70 chaperone complex--DnaK,
DnaJ, and GrpE--in initiating phage lambda DNA replication by
sequestering and releasing lambda P protein. Proc. Natl. Acad. Sci.
89:12108-12111); the fcsA gene (Kudo, T., et al. 1977.
Characteristics of a cold-sensitive cell division mutant
Escherichia coli K-12. Agric. Biol. Chem. 41:97-107); the fic gene
(Utsumi, R., et al. 1982. Involvement of cyclic AMP and its
receptor protein in filamentation of an Escherichia coli fic
mutant. J. Bacteriol. 151:807-812; Komano, T., et al. 1991.
Functional analysis of the fic gene involved in regulation of cell
division. Res. Microbiol. 142:269-277); the fis gene
(Spaeny-Dekking, L. et al. 1995. Effects of N-terminal deletions of
the Escherichia coli protein Fis on the growth rate, tRNA (2Ser)
expression and cell morphology. Mol. Gen. Genet. 246:259-265); the
ftsA gene (Bi, E., and J. Lutkenhaus. 1990. Analysis of ftsZ
mutations that confer resistance to the cell division inhibitor
SulA (SfiA). J. Bacterial. 172:5602-5609; Dai, K, and J.
Lutkenhaus. 1992. The proper ration of FtsZ to FtsA is required for
cell division to occur in Escherichia coli. J. Bacteriol.
174:6145-6151); the ftsE gene (Taschner, P. E. et al. 1988.
Division behavior and shape changes in isogenic ftsZ, ftsQ, ftsA,
pbpB, and ftsE cell division mutants of Escherichia coli during
temperature shift experiments. J. Bacteriol. 170:1533-1540); the
ftsH gene (Ogura, T. et al. 1991. Structure and function of the
ftsH gene in Escherichia coli. Res. Microbiol. 142:279-282); the
ftsl gene (Begg, K. J., and W. D. Donachie. 1985. Cell shape and
division in Escherichia coli: experiments with shape and division
mutants. J. Bacteriol. 163:615-622); the ftsj gene (Ogura, T. et
al. 1991. Structure and function of the ftsH gene in Escherichia
coli. Res. Microbiol. 142:279-282); the ftsL gene (Guzman, et al.
1992. FtsL, an essential cytoplasmic membrane protein involved in
cell division in Escherichia coli. J. Bacteriol. 174:7716-7728);
the ftsN gene (Dai, K. et al. 1993. Cloning and characterization of
ftsN, an essential cell division gene in Escherichia coli isolated
as a multicopy suppressor of ftsA12(Ts). J. Bacteriol.
175:3790-3797); the ftsQ gene (Wang, X. D. et al. 1991. A factor
that positively regulates cell division by activating transcription
of the major cluster of essential cell division genes of
Escherichia coli. EMBO J. 10:3362-3372); the ftsW gene (Khattar, M.
M. et al. 1994. Identification of FtsW and characterization of a
new ftsW division mutant of Escherichia coli. J. Bacteriol.
176:7140-7147); the ftsX (ftsS) gene (Salmond, G. P. and S.
Plakidou. 1984. Genetic analysis of essential genes in the ftsE
region of the Escherichia coli genetic map and identification of a
new cell division gene, ftsS. Mol. Gen. Genet. 197:304-308); the
ftsy gene (Gill, D. R. and G. P. Salmond. 1990. The identification
of the Escherichia coli ftsy gene product: an unusual protein. Mol.
Microbiol. 4:575-583); the ftsZ gene (Ward, J. E., and J.
Lutkenhaus. 1985. Overproduction of FtsZ induces minicell
formation. Cell. 42:941-949; Bi, E., and J. Lutkenhaus. 1993. Cell
division inhibitors SulA and MinCD prevent formation of the FtsZ
ring. J. Bacteriol. 175:1118-1125); the gyrB gene (Mulder, E., et
al. 1990. The Escherichia coli minB mutation resembles gyrB in
defective nucleoid segregation and decreased negative supercoiling
of plasmids. Mol. Gen. Genet. 221:87-93); the hlfB (ftsH)gene
(Herman, C., et al. 1993. Cell growth and lambda phage development
controlled by the same essential Escherichia coli gene, ftsH/hflB.
Proc. Natl. Acad. Sci. 90:10861-10865); the hfq gene (Takada, A.,
et al. 1999. Negative regulatory role of the Escherichia coli hfq
gene in cell division. Biochem. Biophys. Res. Commun. 266:579-583;
the hipA gene (Scherrer, R., and H. S. Moyed. 1988. Conditional
impairment of cell division and altered lethality in hipA mutants
of Escherichia coli K-12. J. Bacteriol. 170:3321-3326); the hipB
gene (Hendricks, E. C., et al. 2000. Cell division, guillotining of
dimer chromosomes and SOS induction in resolution mutants (dif,
xerC and xerD) of Escherichia coli. Mol. Microbiol. 36:973-981);
the hns gene (Kaidow, A., et al. 1995. Anucleate cell production by
Escherichia coli delta hns mutant lacking a histone-like protein,
H-NS. J. Bacteriol. 177:3589-3592); the htrB gene (Karow, M., et
al. 1991. Complex phenotypes of null mutations in the htr genes,
whole products are essential for Escherichia coli growth at
elevated temperatures. Res. Microbiol. 142:289-294); the lpxC
(envA)gene (Beall, B., and J. Lutkenhaus. 1987. Sequence analysis,
transcriptional organization, and insertional mutagenesis of the
envA gene of Escherichia coli. J. Bacteriol. 169:5408-5415; Young,
K., et al. 1995. The envA permeability/cell division gene of
Escherichia coli encodes the second enzyme of lipid A biosynthesis.
UDP-3-O-(R-3-hydroxymyristoyl)-N-acetylglucosamine deacetylase. J.
Biol. Chem. 270:30384-30391); the malE gene (Pichoff, S., et al.
1997. MinCD-independent inhibition of cell division by a protein
that fuses MalE to the topological specificity factor MinE. J.
Bacteriol. 179:4616-4619); the minA gene, (Davie, E., et al. 1984.
Genetic basis of minicell formation in Escherichia coli K-12. J.
Bacteriol. 158:1202-1203); the minB gene (Davie, E., et al. 1984.
Genetic basis of minicell formation in Escherichia coli K-12. J.
Bacteriol. 158:1202-1203); the minC gene (de Boer, P. A., et al.
1990. Central role for the Escherichia coli minC gene product in
two different cell division-inhibition systems. Proc. Natl. Acad.
Sci. 87:1129-1133); the minD gene (Labie, C., et al. 1990.
Minicell-forming mutants of Escherichia coli: suppression of both
DicB- and MinD-dependent division inhibition by inactivation of the
minC gene product. J. Bacteriol. 172:5852-5855; Hayashi, I., et al.
2001. Structural and functional studies of MinD ATPase:
implications for the molecular recognition of the bacterial cell
division apparatus. EMBO J. 20:1819-1828); the minE gene (de Boer,
P. A., et al. 1989. A division inhibitor and a topological
specificity factor coded for by the minicell locus determine proper
placement of the division septum in E. coli. Cell. 56:641-649); the
mreB gene (Doi, M., et al. 1988. Determinations of the DNA sequence
of the mreB gene and of the gene products of the mre region that
function in formation of the rod shape of Escherichia coli cells.
J. Bacteriol. 170:4619-4624); the mreC gene (Wachi, M., et al.
1989. New mre genes mreC and mreD, responsible for formation of the
rod shape of Escherichia coli cells. J. Bacteriol. 171:6511-6516);
the mreD gene (Wachi, M., et al. 1989. New mre genes mreC and mreD,
responsible for formation of the rod shape of Escherichia coli
cells. J. Bacteriol. 171:6511-6516); the muka gene (Hiraga, S., et
al. 1989. Chromosome partitioning in Escherichia coli: novel
mutants producing anucleate cells. J. Bacteriol. 171:1496-1505);
the mukB gene (Hiraga, S., et al. 1991. Mutants defective in
chromosome partitioning in E. coli. Res. Microbiol. 142:189-194);
the mukE gene (Yamanaka, K., et al. 1996. Identification of two new
genes, muke and mukF, involved in chromosome partitioning in
Escherichia coli. Mol. Gen. Genet. 250:241-251; Yamazoe, M., et al.
1999. Complex formation of MukB, MukE and MukF proteins involved in
chromosome partitioning in Escherichia coli. EMBO J. 18:5873-5884);
the mukF gene (Yamanaka, K., et al. 1996. Identification of two new
genes, mukE and mukF, involved in chromosome partitioning in
Escherichia coli. Mol. Gen. Genet. 250:241-251; Yamazoe, M., et al.
1999. Complex formation of MukB, MukE and MukF proteins involved in
chromosome partitioning in Escherichia coli. EMBO J. 18:5873-5884);
the parC gene (Kato, J., et al. 1988. Gene organization in the
region containing a new gene involved in chromosome partition in
Escherichia coli. J. Bacteriol. 170:3967-3977); the parE gene
(Roberts, R. C., et al. 1994. The parDE operon of the
broad-host-range plasmid RK2 specifies growth inhibition associated
with plasmid loss. J. Mol. Biol. 237:35-51); the pbpA gene
(Rodriguez, M. C., and M. A. de Pedro. 1990. Initiation of growth
in pbpAts and rodAts mutants of Escherichia coli. FEMS Microbiol.
Lett. 60:235-239); the pcnB gene (Makise, M., et al. 1999.
Identification of a high-copy-number plasmid suppressor of a lethal
phenotype caused by mutant DnaA protein which has decreased
intrinsic ATPase activity. Biol. Pharm. Bull. 22:904-909); the parF
(plsC in E. coli) gene product from Salmonella (Luttinger, A. L.,
et al. 1991. A cluster of genes that affects nucleoid segregation
in Salmonella typhimurium. New Biol. 3:687-697); the rpoS gene
(Cam, K., et al. 1995. Sigma S-dependent overexpression of ftsZ in
an Escherichia coli K-12 rpoB mutant that is resistant to the
division inhibitors DicB and DicF RNA. Mol. Gen. Genet.
248:190-194); the rcsB gene (Gervais, F. G., et al. 1992. The rcsB
gene, a positive regulator of colanic acid biosynthesis in
Escherichia coli, is also an activator of ftsZ expression. J.
Bacteriol. 174:3964-3971); the rcsF gene (Gervais, F. G., and G. R.
Drapeau. 1992. Identification, cloning, and characterization of
rcsF, a new regulator gene for exopolysaccharide synthesis that
suppresses the division mutation ftsZ84 in Escherichia coli K-12.
J. Bacteriol. 174:8016-8022); the rodA gene (Rodriguez, M. C., and
M. A. de Pedro. 1990. Initiation of growth in pbpAts and rodAts
mutants of Escherichia coli. FEMS Microbiol. Lett. 60:235-239); the
sdiA (sulB, sfiB) gene (Wang, X. D., et al. 1991. A factor that
positively regulates cell division by activating transcription of
the major cluster of essential cell division genes of Escherichia
coli. EMBO J. 10:3363-3372); the sefA (fabZ) gene (Mohan, S., et
al. 1994. An Escherichia coli gene (FabZ) encoding
(3R)-hydroxymyristoyl acyl carrier protein dehydrase. Relation to
fabA and suppression of mutations in lipid A biosynthesis. J. Biol
Chem. 269:32896-32903); the sfiC gene (D'Ari, R., and 0. Huisman.
1983. Novel mechanism of cell division inhibition associated with
the SOS response in Escherichia coli. J. Bacteriol. 156:243-250);
the sulA gene (Bi, E., and J. Lutkenhaus. 1990. Interaction between
the min locus and ftsZ. J. Bacteriol. 172:5610-5616; Bi, E., and J.
Lutkenhaus. 1993. Cell division inhibitors SulA and MinCD prevent
formation of the FtsZ ring. J. Bacteriol. 175:1118-1125); the stfz
gene (Dewar, S. J., and W. D. Donachie. 1993. Antisense
transcription of the ftsZ-ftsA gene junction inhibits cell division
in Escherichia coli. J. Bacteriol. 175:7097-7101); the tolC gene
(Hiraga, S., et al. 1989. Chromosome partitioning in Escherichia
coli: novel mutants producing anucleate cells. J. Bacteriol.
171:1496-1505; Hiraga, S., et al. 1991. Mutants defective in
chromosome partitioning in E. coli. Res. Microbiol. 142:189-194);
and the zipA gene (Hale, C. A., and P. A. de Boer. 1997. Direct
binding of FtsZ to ZipA, an essential component of the septal ring
structure that mediates cell division in E. coli. Cell.
88:175-185).
[0301] The guanosine 5'-diphosphate 3' diphosphate (ppGpp) or
guanosine 5'-triphosphate 3' diphosphate (pppGpp) nucleotides,
collectively (p)ppGpp, found in E. coli or in other members of the
Eubacteria, Eucarya or Archaea may be employed to produce minicells
(Vinella, D., et al. 1993. Penicillin-binding protein 2
inactivation in Escherichia coli results in cell division
inhibition, which is relieved by FtsZ overexpression. J. Bacteriol.
175:6704-6710; Navarro, F., et al. Analysis of the effect of ppGpp
on the ftsQAZ operon in Escherichia coli. Mol. Microbiol.
29:815-823). The levels, or rate of production of (p)ppGpp may be
increased or decreased. By way of non-limiting example, increased
(p)ppGpp production results from induction of the stringent
response. The stringent response in E. coli is a physiological
response elicited by a failure of the capacity for tRNA
aminoacylation to keep up with the demands of protein synthesis.
This response can be provoked either by limiting the availability
of amino acids or by limiting the ability to aminoacylate tRNA even
in the presence of abundant cognate amino acids. Many features of
the stringent response behave as if they are mediated by
accumulation of (p)ppGpp. The accumulation of (p)ppGpp can also be
provoked by nutritional or other stress conditions in addition to a
deficiency of aminoacyl-tRNA. See Cashel et al., "The Stringent
Response," Chapter 92 in: Escherichia coli and Salmonella
typhimurium: Cellular and Molecular Biology, 2nd Ed., Neidhardt,
Frederick C., Editor in Chief, American Society for Microbiology,
Washington, D.C., 1996, Volume 1, pages 1458-1496, and references
cited therein.
[0302] By way of non-limiting example, factors that may provoke the
stringent response include the lyt gene or gene product (Harkness,
R. E., et al. 1992. Genetic mapping of the lyta and lytB loci of
Escherichia coli, which are involved in penicillin tolerance and
control of the stringent response. Can J. Microbiol. 38:975-978),
the relA gene or gene product (Vinella, D., and R. D'Ari. 1994.
Thermoinducible filamentation in Escherichia coli due to an altered
RNA polymerase beta subunit is suppressed by high levels of ppGpp.
J. Bacteriol. 176:96-972), the relB gene or gene product
(Christensen, S. K., et al. 2001. RelE, a global inhibitor of
translation, is activated during nutritional stress. Proc. Natl.
Acad. Sci. 98:14328-14333), the relC (rplK) gene or gene product
(Yang, X., and E. E. Ishiguro. 2001. Involvement of the N Terminus
of Ribosomal Protein L11 in Regulation of the RelA Protein of
Escherichia coli. J. Bacteriol. 183:6532-6537), the relX gene or
gene product (St. John, A. C., and A. L. Goldberg. 1980. Effects of
starvation for potassium and other inorganic ions on protein
degradation and riboncleic acid synthesis in Escherichia coli. J.
Bacteriol. 143:1223-1233), the spoT gene or gene product (Vinella,
D., et al. 1996. Mecillinam resistance in Escherichia coli is
conferred by loss of a second activity of the AroK protein. J.
Bacteriol. 178:3818-3828), the gpp gene or gene product (Keasling,
J. D., et al. 1993. Guanosine pentaphosphate phosphohydrolase of
Escherichia coli is a long-chain exopolyphosphatase. Proc. Natl.
Acad. Sci. 90:7029-7033), the ndk gene or gene product (Kim, H. Y.,
et al. 1998. Alginate, inorganic polyphosphate, GTP and ppGpp
synthesis co-regulated in Pseudomonas aeruginosa: implications for
stationary phase survival and synthesis of RNA/DNA precursors. Mol.
Microbiol. 27:717-725), the rpoB gene or gene product (Vinella, D.,
and R. D'Ari. 1994. Thermoinducible filamentation in Escherichia
coli due to an altered RNA polymerase beta subunit is suppressed by
high levels of ppGpp. J. Bacteriol. 176:96-972), the rpoC gene or
gene product (Bartlett, M. S., et al. 1998. RNA polymerase mutants
that destabilize RNA polymerase-promoter complexes alter
NTP-sensing by rrn P1 promoters. J. Mol. Biol. 279:331-345), the
rpoD gene or gene product (Hernandez, V. J., and M. Cashel. 1995.
Changes in conserved region 3 of Escherichia coli sigma 70 mediate
ppGpp-dependent functions in vivo. 252:536-549), glnF gene or gene
product (Powell, B. S., and D. L. Court. 1998. Control of ftsZ
expression, cell division, and glutamine metabolism in
Luria-Bertani medium by the alarmone ppGpp in Escherichia coli. J.
Bacteriol. 180:1053-1062), or glnD gene or gene product (Powell, B.
S., and D. L. Court. 1998. Control of ftsZ expression, cell
division, and glutamine metabolism in Luria-Bertani medium by the
alarmone ppGpp in Escherichia coli. J. Bacteriol. 180:1053-1062).
These genes or gene products, and/or expression thereof, may be
manipulated to create minicells.
[0303] II.A.3. Bacillus subtilis Genes
[0304] Exemplary genes and gene products from B. subtilis, the
expression and/or sequence of which can be manipulated so as to
stimulate minicell production in B. subtilis or any other organism,
as can homologs thereof from any species, include without
limitation, the divl (divD)gene (Van Alstyne, D., and M. I. Simon.
1971. Division mutants of Bacillus subuilis: isolation of PBS1
transduction of division-specific markers. J. Bacteriol.
108:1366-1379); the divIB (dds, ftsQ) gene (Harry, E. J., et al.
1993. Characterization of mutations in divIB of Bacillus subuilis
and cellular localization of the DivIB protein. Mol. Microbiol.
7:611-621; Harry E. J., et al. 1994. Expression of divIB of
Bacillus subtilis during vegetative growth. J. Bacteriol.
176:1172-1179); the divIC gene product from B. subtilis or
homologues of this gene or gene product found in other members of
the Eubacteria, Eucarya or Archaea may be employed to produce
minicells (Levin, P. A., and R. Losick. 1994. Characterization of a
cell division gene from Bacillus subuilis that is required for
vegetative and sporulation septum formation. J. Bacteriol.
176:1451-1459; Katis, V. L. , et al. 1997. The Bacillus subtilis
division protein DivIC is a highly abundant membrane-bound protein
that localizes to the division site; the divII (divC) gene (Van
Alstyne, D., and M. I. Simon. 1971. Division mutations of Bacillus
subuilis: isolation and PBS1 transduction of division-specific
markers. J. Bacteriol. 108:1366-1379); the divIVA (divD) gene (Cha,
J.-H., and G. C. Stewart. 1997. The divIVA minicell locus of
Bacillus subuilis. J. Bacteriol. 179:1671-1683); the divIVC (divA)
gene (Van Alstyne, D., and M. I. Simon. 1971. Division mutations of
Bacillus subuilis: isolation and PBS1 transduction of
division-specific markers. J. Bacteriol. 108: 1366-1379); the divV
(divB) gene (Van Alstyne, D., and M. I. Simon. 1971. Division
mutations of Bacillus subuilis: isolation and PBS1 transduction of
division-specific markers. J. Bacteriol. 108:1366-1379); the erzA
(ytwp) gene (Levin, P. A., et al. 1999. Identification and
regulation of a negative regulator of FtsZ ring formation in
Bacillus subuilis. Proc. Natl. Acad. Sci. 96:9642-9647); the ftsA
(spoIIN) gene (Feucht, A., et al. 2001. Cytological and biochemical
characterization of the FtsA cell division protein of Bacillus
subtilis. Mol. Microbiol. 40:115-125); the ftsE gene (Yoshida, K.,
et al. 1994. Cloning and nucleotide sequencing of a 15 kb region of
the Bacillus subuilis genome containing the iol operon.
Microbiology. 140:2289-2298); the ftsH gene (Deuerling. E., et al.
1995. The ftsH gene of Bacillus subtilis is transiently induced
after osmotic and temperature upshift. J. Bacteriol. 177:4105-4112;
Wehrl, W., et al. 2000. The FtsH protein accumulates at the septum
of Bacillus subuilis during cell division and sporulation. J.
Bacteriol. 182:3870-3873); the ftsK gene (Sciochetti, S. A., et al.
2001. Identification and characterization of the dif Site from
Bacillus subuilis. J. Bacteriol. 183:1058-1068); the ftsL
(yIID)gene (Daniel, R. A., et al. 1998. Characterization of the
essential cell division gene ftsL (yIID) of Bacillus subuilis and
its role in the assembly of the division apparatus. Mol. Microbiol.
29:593-604); the ftsW gene (Ikeda, M., et al. 1989. Structural
similarity among Escherichia coli FtsW and RodA proteins and
Bacillus subuilis SpoVE protein, which function in cell division,
cell elongation, and spore formation, respectively. J. Bacteriol.
171:6375-6378); the ftsX gene (Reizer, J., et al. 1998. A novel
protein kinase that controls carbon catabolite repression in
bacteria. Mol. Microbiol. 27:1157-1169); the ftsZ gene (Beall, B.,
and J. Lutkenhaus). FtsZ in Bacillus subuilis is required for
vegetative septation and for asymmetric septation during
sporulation. Genes and Dev. 5:447-45); the gcaD gene (Hove-Jensen,
B. 1992. Identification of tms-26 as an allele of the gcaD gene,
which encodes N-acetylglucosamine 1-phosphate uridyltransferase in
Bacillus subuilis. J. Bacteriol. 174:6852-6856); the gid (ylyC)
gene (Kunst, F., et al. 1997. The complete genome sequence of the
gram-positive bacterium Bacillus subuilis. Nature. 390:237-238);
the gidA gene (Ogasawara, N., and H. Yoshikawa. 1992. Genes and
their organization in the replication origin region of the
bacterial chromosome. Mol. Microbiol. 6:629-634; Nakayashiki, T.,
and H. Inokuchi. 1998. Novel temperature-sensitive mutants of
Escherichia coli that are unable to grow in the absence of
wild-type tRNA6Leu. J. Bacteriol. 180:2931-2935); the gidB gene
(Ogasawara, N., and H. Yoshikawa. 1992. Genes and their
organization in the replication origin region of the bacterial
chromosome. Mol. Microbiol. 6:629-634; Nakayashiki, T., and H.
Inokuchi. 1998. Novel temperature-sensitive mutants of Escherichia
coli that are unable to grow in the absence of wild-type tRNA6Leu.
J. Bacteriol. 180:2931-2935); the lytC (cwlB) gene (Blackman, S.
A., et al. 1998. The role of autolysins during vegetative growth of
Bacillus subuilis 168. Microbiology. 144:73-82); the lytD (cwlG)
gene (Blackman, S. A., et al. 1998. The role of autolysins during
vegetative growth of Bacillus subuilis 168. Microbiology.
144:73-82); the lytE (cwlF) gene (Ishikawa, S., et al. 1998.
Regulation of a new cell wall hydrolase gene, cwlF, which affects
cell separation in Bacillus subuilis. J. Bacteriol.
180:23549-2555); the lytF (cwlE, yhdD) gene (Ohnishi, R., et al.
1999. Peptidoglycan hydrolase lytF plays a role in cell separation
with CwlF during vegetative growth of Bacillus subuilis. J.
Bacteriol. 181:3178-1384); the maf gene (Butler, Y. X., et al.
1993. Amplification of the Bacillus subtilis maf gene results in
arrested septum formation. J. Bacteriol. 175:3139-3145); the minC
gene (Varley, A. W., and G. C. Stewart. 1992. The divIVB region of
the Bacillus subuilis chromosome encodes homologs of Escherichia
coli septum placement (minCD) and cell shape (mreBCD) determinants.
J. Bacteriol. 174:6729-6742; Barak, I., et al. 1998. MinCD proteins
control the septation process during sporulation of Bacillus
subuilis. J. Bacteriol. 180:5327-5333); the minD gene (Varley, A.
W., and G. C. Stewart. 1992. The divIVB region of the Bacillus
subuilis chromosome encodes homologs of Escherichia coli septum
placement (minCD) and cell shape (mreBCD) determinants. J.
Bacteriol. 174:6729-6742; Barak, I., et al. 1998. MinCD proteins
control the septation process during sporulation of Bacillus
subuilis. J. Bacteriol. 180:5327-5333); the pbpB gene (Daniel, R.
A., and J. Errington. 2000. Intrinsic instability of the essential
cell division protein FtsL of Bacillus subuilis and a role for
DivIB protinein FtsL turnover. Mol. Microbiol. 35:278-289); the
ponA gene (Pederson, L. B., et al. Septal localization of
penicillin-binding protein 1 in Bacillus subtilis. J. Bacteriol.
181:3201-3211); the prfA gene (Popham, D. L., and P. Setlow. 1995.
Cloning, nucleotide sequence, and mutagenesis of the Bacillus
subuilis ponA operon, which codes for penicillin-binding protein
(PBP) 1 and a PBP-related factor. J. Bacteriol. 177:326-335); the
rodB gene (Burdett, I. D. 1979. Electron microscope study of the
rod-to-coccus shape change in a temperature-sensitive rod- mutant
of Bacillus subuilis. J. Bacteriol. 137:1395-1405; Burdett, I. D.
1980. Quantitative studies of rod--coccus morphogenesis in a
temperature-sensitive rod- mutant of Bacillus subtilis. J. Gen.
Microbil. 121:93-103); the secA gene (Sadaie, Y., et al. 1991.
Sequencing reveals similarity of the wild-type div+gene of Bacillus
subuilis to the Escherichia coli secA gene. Gene. 98:101-105); the
smc gene (Britton, R. A., et al. 1998. Characterization of a
prokaryotic SMC protein involved in chromosome partitioning. Genes
Dev. 12:1254-1259; Moriya, S., et al. 1998. A Bacillus subuilis
gene-encoding protein homologous to eukaryotic SMC motor protein is
necessary for chromosome partition. Mol. Microbiol. 29:179-187;
Hirano, M., and T. Hirano. 1998. ATP-dependent aggregation of
single-stranded DNA by a bacterial SMC homodimer. EMBO J.
17:7139-7148); the spoIIE gene (Feucht, a., et al. 1996.
Bifunctional protein required for asymmetric cell division and
cell-specific transcription in Bacillus subuilis. Genes Dev.
10:794-803; Khvorova, A., et al. 1998. The spoIIE locus is involved
in the Spo0A-dependent switch in the localization of FtsZ rings in
Bacillus subuilis. J. Bacteriol. 180:1256-1260; Lucet, I., et al.
2000. Direct interaction between the cell division protein FtsZ and
the cell differentiation protein SpoIIE. EMBO J. 19:1467-1475); the
spo0A gene (Ireton, K., et al. 1994.- spo0J is required for normal
chromosome segregation as well as the initiation of sporulation in
Bacillus subuilis. J. Bacteriol. 176:5320-5329); the spoIVF gene
(Lee, S., and C. W. Price. 1993. The minCD locus of Bacillus
subuilis lacks the minE determinant that provides topological
specificity to cell division. Mol. Microbiol. 7:601-610); the spo0J
gene (Lin, D. C., et el. 1997. Bipolar localization of a chromosome
partition protein in Bacillus subuilis. Proc. Natl. Acad. Sci.
94:4721-4726; Yamaichi, Y., and H. Niki. 2000. Active segregation
by the Bacillus subuilis partitioning system in Escherichia coli.
Proc. Natl. Acad. Sci. 97:14656-14661); the smc gene (Moriya, S.,
et al. 1998. A Bacillus subuilis gene-encoding protein homologous
to eukaryotic SMC motor protein is necessary for chromosome
partition. Mol. Microbiol. 29:179-187); the ripX gene (ciochetti,
S. A. et al. 1999. The ripX locus of Bacillus subuilis encodes a
site-specific recombinase involved in proper chromosome
partitioning. J. Bacteriol. 181:6053-6062); and the spoIIIhE gene
(Wu, L. J., and J. Errington. 1994. Bacillus subuilis spoIIIE
protein required for DNA segregation during asymmetric cell
division. Science. 264:572-575); the gene corresponding to the B.
subtilis mutant alleal ts-31 (Errington, J., and A. D. Richard.
Cell division during growth and sporulation. In A. L. Sonenshein,
J. A. Hoch., and R. Losick (eds.). Bacillus subuilis and its
closest relatives: from genes to cells. American Society for
Microbiology, Washington D.C.); the gene corresponding to the B.
subtilis mutant alleal ts-526 (Id.); the yacA gene (Kunst, F., et
al. 1997. The complete genome sequence of the gram-positive
bacterium Bacillus subuilis. Nature. 390:237-238); the yfhF gene
(Kunst, F., et al. 1997. The complete genome sequence of the
gram-positive bacterium Bacillus subuilis. Nature. 390:237-238);
the yfhK gene (Kunst, F., et al. 1997. The complete genome sequence
of the gram-positive bacterium Bacillus subuilis. Nature.
390:237-238); the yjoB gene (Kunst, F., et al. 1997. The complete
genome sequence of the gram-positive bacterium Bacillus subtilis.
Nature. 390:237-238); and the ywbG gene (Smith, T. J., et al. 2000.
Autolysins of Bacillus subtilis: multiple enzymes with multiple
functions. Microbiology. 146:249-262).
[0305] II.A.3. Saccharomyes cervisiae Genes
[0306] Exemplary genes and gene products from S. cerevisiae the
expression and/or sequence of which can be manipulated so as to
stimulate minicell production in any organism, as can homologs
thereof from any species, include without limitation, the trf gene
product family (TRF1, TRF2, TRF3, TRF4, and TRF5) from
Saccharomyces cerevisiae (Sadoff, B. U., et al. 1995. Isolation of
mutants of Saccharomyces cerevisiae requiring DNA topoisomerase I.
Genetics. 141:465-479; Castano, I. B., et al. 1996. A novel family
of TRF (DNA topoisomerase I-related function) genes required for
proper nuclear segregation. Nucleic Acids Res. 2404-2410); the 1BD1
gene product from Saccharomyces cerevisiae (Lee, J., et al. 1999.
Ibd1p, a possible spindle pole body associated protein, regulates
nuclear division and bud separation in Saccharomyces cerevisiae.
Biochim. Biophys. Acta. 1449:239-253); the plol gene product from
Saccharomyces cerevisiae (Cullen, C. F., et al. 2000. A new genetic
method for isolating functionally interacting genes: high
plol(+)-dependent mutants and their suppressors define genes in
mitotic and septation pathways in fission yeast. Genetics.
155:1541-1534); the cdc7 locus product(s) from Saccharomyces
cerevisiae or homologues of this found in other members of the
Eubacteria, Eucarya or Archaea may be employed to produce minicells
(Biggins, s. et al. 2001. Genes involved in sister chromatid
separation and segregation in the budding yeast Saccharomyces
cerevisiae. Genetics. 159:453-470); the cdcl5 locus product(s) from
Saccharomyces cerevisiae or homologues of this found in other
members of the Eubacteria, Eucarya or Archaea may be employed to
produce minicells (Mah, A. S., et al. 2001. Protein kinase Cdcl5
activates the Dbf2Mob1 kinase complex. Proc. Natl. Acad. Sci.
98:7325-7330); the cdc1 1 locus product(s) from Saccharomyces
cerevisiae or homologues of this found in other members of the
Eubacteria, Eucarya or Archaea may be employed to produce minicells
(Fares, H., et al. 1996. Identification of a developmentally
regulated septin and involvement of the septins in spore formation
in Saccharomyces cerevisiae. J. Cell Biol. 132:399-411); the spgl
locus product(s) from Saccharomyces cerevisiae or homologues of
this found in other members of the Eubacteria, Eucarya or Archaea
may be employed to produce minicells (Cullen, C. F., et al. 2000. A
new genetic method for isolating functionally interacting genes:
high plol(+)-dependent mutants and their suppressors define genes
in mitotic and septation pathways in fission yeast. Genetics.
155:1521-1534); the sid2 locus product(s) from Saccharomyces
cerevisiae or homologues of this found in other members of the
Eubacteria, Eucarya or Archaea may be employed to produce minicells
(Cullen, C. F., et al. 2000. A new genetic method for isolating
functionally interacting genes: high plol(+)-dependent mutants and
their suppressors define genes in mitotic and septation pathways in
fission yeast. Genetics. 155:1521-1534); the cdc8 gene product from
Saccharomyces cerevisiae (Cullen, C. F., et al. 2000. A new genetic
method for isolating functionally interacting genes: high
plol(+)-dependent mutants and their suppressors define genes in
mitotic and septation pathways in fission yeast. Genetics.
155:1521-1534); the rhol gene product from Saccharomyces cerevisiae
(Cullen, C. F., et al. 2000. A new genetic method for isolating
functionally interacting genes: high plol(+)-dependent mutants and
their suppressors define genes in mitotic and septation pathways in
fission yeast. Genetics. 155:1521-1534); the mpd1 gene product from
Saccharomyces cerevisiae (Cullen, C. F., et al. 2000. A new genetic
method for isolating functionally interacting genes: high
plol(+)-dependent mutants and their suppressors define genes in
mitotic and septation pathways in fission yeast. Genetics.
155:1521-1534); the mpd2 gene product from Saccharomyces cerevisiae
(Cullen, C. F., et al. 2000. A new genetic method for isolating
functionally interacting genes: high plol(+)-dependent mutants and
their suppressors define genes in mitotic and septation pathways in
fission yeast. Genetics. 155:1521-1534); the smy2 gene product from
Saccharomyces cerevisiae (Cullen, C. F., et al. 2000. A new genetic
method for isolating functionally interacting genes: high
plol(+)-dependent mutants and their suppressors define genes in
mitotic and septation pathways in fission yeast. Genetics.
155:1521-1534); the cdcl6 gene product from Saccharomyces
cerevisiae (Heichman, K. A., and J. M. Roberts. 1996. The yeast
CDC16 and CDC27 genes restrict DNA replication to once per cell
cycle. Cell. 85:39-48); the dmal gene product from Saccharomyces
cerevisiae (Murone, M., and V. Simanis. 1996. The fission yeast
dmal gene is a component of the spindle assembly checkpoint,
required to prevent septum formation and premature exit from
mitosis if spindle function is compromised. EMBO J. 15:6605-6616);
the plo gene product from Saccharomyces cerevisiae (Cullen, C. F.,
et al. -2000. A new genetic method for isolating functionally
interacting genes: high plol(+)-dependent mutants and their
suppressors define genes in mitotic and septation pathways in
fission yeast. Genetics. 155:1521-1534); the byr3 gene product from
Saccharomyces cerevisiae (Cullen, C. F., et al. 2000. A new genetic
method for isolating functionally interacting genes: high
plol(+)-dependent mutants and their suppressors define genes in
mitotic and septation pathways in fission yeast. Genetics.
155:1521-1534); the byr4 gene product from Saccharomyces cerevisiae
(Cullen, C. F., et al. 2000. A new genetic method for isolating
functionally interacting genes: high plol(+)-dependent mutants and
their suppressors define genes in mitotic and septation pathways in
fission yeast. Genetics. 155:1521-1534); the pdsl gene product from
Saccharomyces cerevisiae (Yamamoto, A., et al. 1996. Pds1p, an
inhibitor of anaphase in budding yeast, plays a critical role in
the APC and checkpoint pathway(s). J. Cell Biol. 133:99-110); the
espI gene product from Saccharomyces cerevisiae (Rao, H., et al.
2001. Degradation of a cohesin subunit by the N-end rule pathway is
essential for chromosome stability. Nature. 410:955-999); the ycs4
gene product from Saccharomyces cerevisiae (Biggins, S., et al.
2001. Genes involved in sister chromatid separation and segregation
in the budding yeast Saccharomyces cerevisiae. Genetics.
159:453-470); the cse4 gene product from Saccharomyces cerevisiae
(Stoler, S. et al. 1995. A mutation in CSE4, an essential gene
encoding a novel chromatin-associated protein in yeast, causes
chromosome nondisjunction and cell cycle arrest at mitosis. Genes
Dev. 9:573-586); the ipl1 gene product from Saccharomyces
cerevisiae (Biggins, S., and A. W. Murray. 2001. The budding yeast
protein kinase Ipl1/Aurora allows the absence of tension to
activate the spindle checkpoint. Genes Dev. 15:3118-3129); the smt3
gene product from Saccharomyces cerevisiae (Takahashi, Y., et al.
1999. Smt3, a SUMO-1 homolog, is conjugated to Cdc3, a component of
septin rings at the mother-bud neck in budding yeast. Biochem.
Biophys. Res. Commun. 259:582-587); the prp16 gene product from
Saccharomyces cerevisiae (Hotz, H. R., and B. Schwer. 1998.
Mutational analysis of the yeast DEAH-box splicing factor Prp16.
Genetics. 149:807-815); the prp19 gene product from Saccharomyces
cerevisiae (Chen, C. H., et al. 2001. Identification and
characterization of two novel components of the Prp19p-associated
complex, Ntc30p and Ntc20p. J. Biol. Chem. 276:488-494); the wssl
gene product from Saccharomyces cerevisiae (Biggins, S., et al.
2001. Genes involved in sister chromatid separation and segregation
in the budding yeast Saccharomyces cerevisiae. Genetics.
159:453-470); the histone H4 gene product from Saccharomyces
cerevisiae (Smith, M. M., et al. 1996. A novel histone H4 mutant
defective in nuclear division and mitotic chromosome transmission.
Mol. Cell Biol. 16:1017-1026); the histone H3 gene product from
Saccharomyces cerevisiae (Smith, M. M., et al. 1996. A novel
histone H4 mutant defective in nuclear division and mitotic
chromosome transmission. Mol. Cell Biol. 16:1017-1026); the cse4
gene product from Saccharomyces cerevisiae (Stoler, S., et al.
1995. A mutation in CSE4, an essential gene encoding a novel
chromatin-associated protein in yeast, causes chromosome
nondisjunction and cell cycle arrest at mitosis. Genes Dev.
9:573-586); the spt4 gene product from Saccharomyces cerevisiae
(Basrai, M. A., et al. 1996. Faithful chromosome transmission
requires Spt4p, a putative regulator of chromatin structure in
Saccharomyces cerevisiae. Mol. Cell Biol. 16:2838-2847); the spts
gene product from Saccharomyces cerevisiae (Yamaguchi, Y., et al.
2001. SPT genes: key players in the regulation of transcription,
chromatin structure and other cellular processes. J. Biochem.
(Tokyo). 129:185-191); the spt6 gene product from Saccharomyces
cerevisiae (Clark-Adams, C. D., and F. Winston. 1987. The SPT6 gene
is essential for growth and is required for delta-mediated
transcription in Saccharomyces cerevisiae. Mol. Cell Biol.
7:679-686); the ndc10 gene product from Saccharomyces cerevisiae
(Chiang, P. W., et al. 1998. Isolation of murine SPT5 homologue:
completion of the isolation and characterization of human and
murine homologues of yeast chromatin structural protein complex
SPT4, SPT5, and SPT6. Genomics. 47:426-428); the ctf13 gene product
from Saccharomyces cerevisiae (Doheny et al., Identification of
essential components of the S. cerevisiae kinetochore, Cell
73:761-774, 1993); the spoI gene product from Saccharomyces
cerevisiae (Tavormina et al. 1997. Differential requirements for
DNA replication in the activation of mitotic checkpoints in
Saccharomyces cerevisiae. Mol. Cell Biol. 17:3315-3322); the cwp1
gene product from Saccharomyces cerevisiae (Tevzadze, G. G., et al.
2000. Spol, a phospholipase B homolog, is required for spindle pole
body duplication during meiosis in Saccharomyces cerevisiae.
Chromosoma. 109:72-85); the dhp1 gene product from
Schizosaccharomyces pombe (Shobuike, T., et al. 2001. The dhp1 (+)
gene, encoding a putative nuclear 5'.fwdarw.3' exoribonuclease, is
required for proper chromosome segregation in fission yeast.
Nucleic Acids Res. 29:1326-1333); the rat1 gene product from
Saccharomyces cerevisiae (Shobuike, T., et al. 2001. The dhp1 (+)
gene, encoding a putative nuclear 5'.fwdarw.3' exoribonuclease, is
required for proper chromosome segregation in fission yeast.
Nucleic Acids Res. 29:1326-1333); the hsk1 gene product from
Saccharomyces cerevisiae (Masai, H., et al. 1995. hsk1 +, a
Schizosaccharomyces pombe gene related to Saccharomyces cerevisiae
CDC7, is required for chromosomal replication. EMBO J.
14:3094-3104); the dfp1 gene product from Saccharomyces cerevisiae
(Takeda, T., et al. 1999. A fission yeast gene, him1(+)/dfp1(+),
encoding a regulatory subunit for Hsk1 kinase, plays essential
roles in S-phase initiation as well as in S-phase checkpoint
control and recovery from DNA damage. Mol. Cell Biol.
19:5535-5547); the dbf4 gene product from Saccharomyces cerevisiae
(Weinreich, M., and B. Stillman. 1999. Cdc7p-Dbf4p kinase binds to
chromatin during S phase and is regulated by both the APC and the
RAD53 checkpoint pathway. EMBO J. 18:5334-5346); the rad53 gene
product from Saccharomyces cerevisiae (Sun, Z., et al. Spk1/Rad53
is regulated by Mec1-dependent protein phosphorylation in DNA
replication and damage checkpoint pathways. Genes Dev. 10:395-406);
the ibd1 gene product from Saccharomyces cerevisiae (Lee, J., et
al. 1999. Ibd1p, a possible spindle pole body associated protein,
regulates nuclear division and bud separation in Saccharomyces
cerevisiae. Biochim. Biophys. Acta. 1449:239-253); and the hrp1
gene product from Saccharomyces cerevisiae (Henry, M., et al. 1996.
Potential RNA binding proteins in Saccharomyces cerevisiae
identified as suppressors of temperature-sensitive mutations in
NPL3. Genetics. 142:103-115).
[0307] II.B. Gene Expression in Minicells
[0308] II.B.1. In General
[0309] In some aspects of the invention, it may be desirable to
alter the expression of a gene and the production of the
corresponding gene product. As is known in the art, and is used
herein, a "gene product" may be a protein (polypeptide) or nucleic
acid. Gene products that are proteins include without limitation
enzymes, receptors, transcription factors, termination factors,
expression factors, DNA-binding proteins, proteins that effect
nucleic acid structure, or subunits of any of the preceding. Gene
products that are nucleic acids include, but are not limited to,
ribosomal RNAs (rRNAs), transfer RNAs (tRNAs), antisense RNAs,
nucleases (including but not limited to catalytic RNAs,
ribonucleases, and the like).
[0310] Depending on the function of a gene product, and on the type
of application of the invention, it may be desirable to increase
protein production, decrease protein production, increase protein
nucleic acid production and/or increase nucleic acid production.
Provided herein are non-limiting examples of genes and gene
products that may be manipulated, individually or in combination,
in order to modulate the expression of gene products to be included
into minicells or parent strains from which minicells are derived.
The expression elements so modulated may be chromosomal and/or
episomal, and may be expressed constitutively or in a regulated
fashion, i.e., repressible and/or inducible. Furthermore, gene
products under the regulation may be either monocistronic or
polycistronic with other genes or with themselves.
[0311] II.B.2. Protein Production
[0312] By way of non-limiting example, increased protein production
may occur through increased gene dosage (increased copy number of a
given gene under the control of the native or artificial promotor
where this gene may be on a plasmid or in more than one copy on the
chromosome), modification of the native regulatory elements,
including, but not limited to the promotor or operator region(s) of
DNA, or ribosomal binding sites on RNA, relevant
repressors/silencers, relevant activators/enhancers, or relevant
antisense nucleic acid or nucleic acid analog, cloning on a plasmid
under the control of the native or artificial promotor, and
increased or decreased production of native or artificial promotor
regulatory element(s) controlling production of the gene or gene
product
[0313] By way of non-limiting example, decreased protein production
may occur through modification of the native regulatory elements,
including, but not limited to the promotor or operator region(s) of
DNA, or ribosomal binding sites on RNA, relevant
repressors/silencers, relevant activators/enhancers, or relevant
antisense nucleic acid or nucleic acid analog, through cloning on a
plasmid under the control of the native regulatory region
containing mutations or an artificial promotor, either or both of
which resulting in decreased protein production, and through
increased or decreased production of native or artificial promotor
regulatory element(s) controlling production of the gene or gene
product.
[0314] As used herein with regards to proteins, "intramolecular
activity" refers to the enzymatic function or structure-dependent
function. By way of non-limiting example, alteration of
intramolecular activity may be accomplished by mutation of the
gene, in vivo or in vitro chemical modification of the protein,
inhibitor molecules against the function of the protein, e.g.
competitive, non-competitive, or uncompetitive enzymatic
inhibitors, inhibitors that prevent protein-protein,
protein-nucleic acid, or protein-lipid interactions, e.g.
expression or introduction of dominant-negative or
dominant-positive protein or other protein fragment(s),
carbohydrate(s), fatty acid(s), lipid(s), and nucleic acid(s) that
may act directly or allosterically upon the protein, and/or
modification of protein, carbohydrate, fatty acid, lipid, or
nucleic acid moieties that modify the gene or gene product to
create the functional protein.
[0315] As used herein with regards to proteins, "intermolecular
function" refers to the effects resulting from an intermolecular
interaction between the protein or nucleic acid and another
protein, carbohydrate, fatty acid, lipid, nucleic acid, or other
molecule(s) in or on the cell or the action of a product or
products resulting from such an interaction. By way of non-limiting
example, intermolecular or intramolecular function may be the act
or result of intermolecular phosphorylation, biotinylation,
methylation, acylation, glycosylation, and/or other signaling
event; this function may be the result of a protein-protein,
protein-nucleic acid, or protein-lipid complex, and/or carrier
function, e.g. the capacity to bind, either covalently or
non-covalently small organic or inorganic molecules, protein(s),
carbohydrate(s), fatty acid(s), lipid(s), and nucleic acid(s); this
function may be to interact with the membrane to recruit other
molecules to this compartment of the cell; this function may be to
regulate the transcription and/or translation of the gene, other
protein, or nucleic acid; and this function may be to stimulate the
function of another process that is not yet described or
understood.
[0316] II.B.3. Nucleic Acid Production
[0317] By way of non-limiting example, increased nucleic acid
production may occur through increased gene dosage (increased copy
number of a given gene under the control of the native or
artificial promotor where this gene may be on a plasmid or in more
than one copy on the chromosome), modification of the native
regulatory elements, including, but not limited to the promotor or
operator region(s) of DNA, or ribosomal binding sites on RNA,
relevant repressors/silencers, relevant activators/enhancers, or
relevant antisense nucleic acid or nucleic acid analog, cloning on
a plasmid under the control of the native or artificial promotor,
and increased or decreased production of native or artificial
promotor regulatory element(s) controlling production of the gene
or gene product.
[0318] By way of non-limiting example, decreased nucleic acid
production may occur through modification of the native regulatory
elements, including, but not limited to the promotor or operator
region(s) of DNA, or ribosomal binding sites on RNA, relevant
repressors/silencers, relevant activators/enhancers, or relevant
antisense nucleic acid or nucleic acid analog, through cloning on a
plasmid under the control of the native regulatory region
containing mutations or an artificial promotor, either or both of
which resulting in decreased protein production, and through
increased or decreased production of native or artificial promotor
regulatory element(s) controlling production of the gene or gene
product.
[0319] As used herein with regards to nucleic acids,
"intramolecular activity" refers to a structure-dependent function.
By way of non-limiting example, alteration of intramolecular
activity may be accomplished by mutation of the gene, in vivo or in
vitro chemical modification of the nucleic acid, inhibitor
molecules against the function of the nucleic acid, e.g.
competitive, non-competitive, or uncompetitive enzymatic
inhibitors, inhibitors that prevent protein-nucleic acid
interactions, e.g. expression or introduction of dominant-negative
or dominant-positive protein or other nucleic acid fragment(s), or
other carbohydrate(s), fatty acid(s), and lipid(s) that may act
directly or allosterically upon the nucleic acid or nucleic
acid-protein complex, and/or modification of nucleic acid moieties
that modify the gene or gene product to create the functional
nucleic acid.
[0320] As used herein with regards to nucleic acids,
"intermolecular function" refers to the effects resulting from an
intermolecular interaction between the nucleic acid and another
nucleic acid, protein, carbohydrate, fatty acid, lipid, or other
molecule(s) in or on the cell or the action of a product or
products resulting from such an interaction. By way of non-limiting
example, intermolecular function may be the act or result of
intermolecular or intramolecular phosphorylation, biotinylation,
methylation, acylation, glycosylation, and/or other signaling
event; this function may be the result of a protein-nucleic acid,
and/or carrier function, e.g. the capacity to bind, either
covalently or non-covalently small organic or inorganic molecules,
protein(s), carbohydrate(s), fatty acid(s), lipid(s), and another
nucleic acid(s); this function may be to interact with the membrane
to recruit other molecules to this compartment of the cell; this
function may be to regulate the transcription and/or translation of
the gene, other nucleic acid, or protein; and this function may be
to stimulate the function of another process that is not yet
described or understood.
[0321] II. C. Genes and Gene Products for Regulation of
Expression
[0322] As is known in the art, a variety of genes, gene products
and expression elements may be manipulated, individually or in
combination, in order to modulate the expression of genes and/or
production gene products. These include, by way of non-limiting
example, RNA polymerases, ribosomes (ribosomal proteins and
ribosomal RNAs), transfer RNAs (tRNAs), amino transferases,
regulatory elements and promoter regions, transportation of
inducible and inhibitory compounds, catabolite repression, general
deletions and modifications, cytoplasmic redox state,
transcriptional terminators, mechanisms for ribosomal targeting,
proteases, chaperones, export apparatus and membrane targeting, and
mechanisms for increasing stability and solubility. Each of these
is discussed in more detail in the following sections.
[0323] II.C. 1. RNA Polymerases
[0324] Included in the design of the invention are techniques that
increase the efficiency of gene expression and protein production
in minicells. By way of non-limiting example, these techniques may
include modification of an endogenous and/or introduction of an
exogenous RNA polymerase. A rpo gene, or any other gene that
encodes a RNA polymerase subunit product from E. coli, or homologs
of this gene or its gene product found in other prokaryotes,
eukaryotes, archaebacteria or organelles (mitochondria,
chloroplasts, plastids and the like) may be employed to increase
the efficiency of gene expression and protein production in parent
cells prior to minicell formation and/or in segregated
minicells.
[0325] The production or activity of a desired gene product may be
increased by increasing the level and/or activity of an RNA
polymerase that transcribes the gene product's cognate gene. The
production or activity of a desired protein gene product may be
increased by decreasing the level and/or activity of an RNA
polymerase that transcribes a gene product that inhibits the
production or function of the desired gene product.
[0326] As one example, manipulation of the rpoA (phs, sez) gene or
gene product from E. coli, or homologs of this gene or gene product
found in other members of the Prokaryotes, Eukaryotes,
Archaebacteria and/or organelles (e.g., mitochondria, chloroplasts,
plastids and the like) may be employed to increase the efficiency
of gene expression and protein production in parent cells prior to
minicell formation and/or in segregated minicells. In addition to
rpoA, E. coli. genes that encode RNA polymerase subunits include
rpoB (ftsR, groN, nitB, rif, ron, stl, stv, tabD, sdgB, mbrD), rpoC
(tabD), rpoD (alt), rpoE, rpoH (fam, hin, htpR), rpoN (glnF, ntrA),
rpoS (abrD, dpeB, katF, nur), and rpoZ (spoS). See Berlyn et al.,
"Linkage Map of Escherichia coli K-12, Edition 9," Chapter 109 in:
Escherichia coli and Salmonella typhimurium: Cellular and Molecular
Biology, 2nd Ed., Neidhardt, Frederick C., Editor in Chief,
American Society for Microbiology, Washington, D.C., 1996, Volume
2, pages 1715-1902, and references cited therein; and Sanderson et
al., "Linkage Map of Salmonella typhimurium, Edition VIII" Chapter
110 in: Escherichia coli and Salmonella typhimurium: Cellular and
Molecular Biology, 2nd Ed., Neidhardt, Frederick C., Editor in
Chief, American Society for Microbiology, Washington, D.C., 1996,
Volume 2, pages 1903-1999, and references cited therein.
[0327] Production of a desired gene product may be preferentially
or selectively enhanced by the introduction of an exogenous RNA
polymerase that specifically recognizes expression sequences that
are operably linked to the corresponding gene. By way of
non-limiting example, the use of a T7 RNA polymerase to selectively
express genes present on expression elements that segregate into
minicells is described herein.
[0328] II.C.2. Ribosomes
[0329] Included in the design of the invention are techniques that
increase the efficiency of gene expression and protein production
in minicells. By way of non-limiting example, these techniques may
include modification of endogenous, and/or addition of exogenous,
ribosomes or ribosomal subunits. The techniques may be employed to
increase the efficiency of gene expression and protein production
in parent cells prior to minicell formation and/or in segregated
minicells.
[0330] As is known in the art, a ribosome includes both proteins
(polypeptides) and RNA (rRNA). Thus, in the case of a gene that
encodes a component of a ribosome, the gene product may be a
protein or an RNA. For a review, see Noller et al., "Ribosomes,"
Chapter 13 in: Escherichia coli and Salmonella typhimurium:
Cellular and Molecular Biology, 2nd Ed., Neidhardt, Frederick C.,
Editor in Chief, American Society for Microbiology, Washington,
D.C., 1996, Volume 1, pages 167-186, and references cited therein.
For the sake of convenience, both ribosomal proteins and rRNAs are
encompassed by the term "ribosomal subunits."
[0331] The production or activity of a desired protein gene product
may be increased by increasing the level and/or activity of a
ribosomal subunit that causes or enhances the translation of the
desired protein. The production or activity of a desired protein
gene product may be increased by decreasing the level and/or
activity of a ribosomal subunit that causes or enhances translation
of a protein that has a negative impact on the production or
activity of the desired protein.
[0332] Exemplary ribosomal genes and gene products that may be
manipulated include without limitation the E. coli genes rimB,
rimC, rimD, rimE, rimF (res), rimG, rimH, rimi, rimj (tcp), rimK,
rimL; rplA, rplB, rplC, rplD, rplE, rplF, rplI, rpU, rplK, rpIL,
rplM, rplN, rplO, rplP, rplQ, rplR, rplS, rplT, rplU, rplV, rplW,
rplX, rplY; rpsA, rpsB, rpsC, rpsE (eps, spc, spcA), rpsF (sdgH),
rpsG, rpsH, rpsI, rpsJ (nusE), rpsK, rpsL (strA), rpsM, rpsN, rpsO,
rpsP, rpsQ, rpsR, rpsS, rpsT, rpsU, rpsV; rrfA, rrfB, rrfC, rrfD,
rrfE, rrfF (rrfDbeta, rrvD), rrfG, rrfH; rrlA, rrlB, rrlC, rrlD,
rrlE, rrlG, rrlH; rrnA, rrnB (csqE, rrnB1), rrnC (cqsB), rrnD
(cqsD), rrnE (rrD1), rrnG, rrnH; rrsA, rrsB, rrsC, rrsD, rrsE,
rrsG, rrsH, and their cognate gene products.
[0333] Homologs of ribosomal genes or gene products found in other
members of the Prokaryotes, Eukaryotes, Archaebacteria and
organelles (including but not limited to mitochondria,
chloroplasts, plastids, and the like) may be employed to increase
the efficiency of gene expression and protein production in parent
cells prior to minicell formation and/or segregated minicells. See,
for example, Barkan, A. and M. Goldschmidt-Clermont, Participation
of nuclear genes in chloroplast gene expression, (2000) Biochimie
82:559-572; Willhoeft, U., H. Bu , and E. Tannich, Analysis of cDNA
Expressed sequence tags from Entamoeba histolytica: Identification
of two highly abundant polyadenylated transcripts with no overt
open reading frames, (March 1999) Protist 150:61-70; Emelyanov, V.,
Evolutionary relationship of Rickettsiae and mitochondria (Febuary
2001) FEBS Letters 501:11-18; and Gray, M., G. Burger and B. Lang,
Mitochondrial Evolution (Mar. 1999) Science 283:1476-1481.
Ribosomal RNA sequences from a multitude of organisms and
organelles are available through the Ribosomal Database Project
(Maidak et al., A new version of the RDP (Ribosomal Database
Project) (1999) Nucleic Acids Research 27:171-173). An index of
ribosomal proteins classified by families on the basis of sequence
similarities is available on-line at
http://www.expasy.ch/cgi-bin/lists?ribosomp.txt; see also
(Ramakrishnan et al., Ribosomal protein structures: insights into
the architecture, machinery and evolution of the ribosome, TIBS
23:208-212, 1998.
[0334] II.C.3. Transfer RNAs (tRNAs)
[0335] Included in the design of the invention are techniques that
increase the efficiency of gene expression and protein production
in minicells. By way of non-limiting example, these techniques may
include utilization and/or modification of endogenous and/or
exogenous transfer RNAs (tRNAs). Manipulation of the tRNA genes or
gene products from E. coli, or homologs of tRNA genes or gene
products found in other members of the Prokaryotes, Eukaryotes,
Archaebacteria and organelles (including but not limited to
mitochondria, chloroplasts, plastids, and the like) may be employed
to increase the efficiency of gene expression and protein
production in parent cells prior to minicell formation and/or in
segregated minicells.
[0336] Exemplary E. coli tRNA genes include, but are not limited
to, the alaT (talA) gene, the alaU (talD) gene, the alaV gene, the
alaW (alaW) gene, the alaX (alaW) gene, the argQ (alaV) gene, the
argu (dnaY, pin) gene, the alaU (talD) gene, the argV(argV2) gene,
the argw gene, the argx gene, the argY (argv) gene, the argz (argv)
gene, the asnT gene, the asnU gene, the asnv gene, the aspT gene,
the aspU gene, the cysT gene, the glnU (supB) gene, the glnV (supE)
gene, the glnW (supB) gene, the gltT (tgtB) gene, the gltU (tgtc)
gene, the gltV (tgtE) gene, the gltW gene, the glyT (sumA) gene,
the glyU (suJD, sumA, sumB, supT) gene, the glyV (ins, mutA) gene,
the glyW (ins, mutC) gene, the glyX gene, the glyY gene, the hisR
(hisT) gene, the ileT gene, the ileU gene, the ileV gene, the ileX
gene, the leuP (leuV) gene, the leuQ (leuV) gene, the leuQ (leuV)
gene, the leuT gene, the leuU gene, the leuV (leuV) gene, the leuW
(feeb) gene, the leuX (supP) gene, the leuZ gene, the lysT gene,
the lysV (supN) gene, the lysW gene, the metT (metT) gene, the metU
(metT) gene, the metV (metZ ) gene, the metW gene, the metY gene,
the pheU (pheR, phew) gene, the pheV gene, the proK (proV) gene,
the proL (prow) gene, the proM (proU) gene, the serT (divE) gene,
the serU (ftsM, supD, supH) gene, the serV (supD) gene, the serw
gene, the serX (serW) gene, the thrT gene, the thrU gene, the thrv
gene, the thrW gene, the trpT (supU) gene, the tyrT (supC) gene,
the tyrU (supM) gene, the atyrV (tyrT, tyrT) gene, the valT gene,
the valU (valU ) gene, the valV (val) gene, the valW (val) gene,
the valX gene, and the valX gene (Komine et al., Genomic
Organization and Physical Mapping of the Transfer RNA Genes in
Escherichia coli K12. J. Mol. Biol. 212:579-598, 1990; Berlyn et
al., "Linkage Map of Escherichia coli K-12, Edition 9, " Chapter
109 in: Escherichia Coli and Salmonella Typhimurium: Cellular and
Molecular Biology, 2.sup.nd Ed., Neidhardt, Frederick C., Editor in
Chief, American Society for Microbiology, Washington, D.C., 1996,
Volume 2, pages 1715-1902, and references cited therein; Sanderson
et al., "Linkage Map of Salmonella typhimurium, Edition VIII"
Chapter 110, Id., pages 1903-1999, and references cited therein;
and Hershey, "Protein Synthesis," Chapter 40 in: Escherichia Coli
and Salmonella Typhimurium: Cellular and Molecular Biology,
Neidhardt, Frederick C., Editor in Chief, American Society for
Microbiology, Washington, D.C., 1987, Volume 2, pages 613-647, and
references cited therein).
[0337] Also included in the modification of transfer RNA molecules
are the transfer RNA processing enzymes. Exemplary E. coli genes
encoding tRNA processing enzymes include, but are not limited to
the rnd gene (Blouin RT, Zaniewski R, Deutscher MP. Ribonuclease D
is not essential for the normal growth of Escherichia coli or
bacteriophage T4 or for the biosynthesis of a T4 suppressor tRNA, J
Biol Chem. 258:1423-1426, 1983) and the rnpAB genes (Kirsebom L A,
Baer M F, Altman S., Differential effects of mutations in the
protein and RNA moieties of RNase P on the efficiency of
suppression by various tRNA suppressors, J Mol Biol. 204:879-888,
1988).
[0338] Also included in the modification of transfer RNA molecules
are modifications in endogenous tmRNAs and/or the introduction of
exogenous tmRNAs to minicells and/or their parent cells. The tmRNA
(a.k.a. 10S RNA) molecules have properties of tRNAs and mRNAs
combined in a single molecule. Examples of tmRNAs are described in
Zwieb et al. (Survey and Summary: Comparative Sequence Analysis of
tmRNA, Nucl. Acids Res. 27:21063-2071, 1999).
[0339] II.C.4. Aminoacyl Synthetases
[0340] Included in the design of the invention are techniques that
increase the efficiency of gene expression and protein production
in minicells. By way of non-limiting example, these techniques may
include utilization and/or modification of endogenous and/or
exogenous aminoacyl synthetases and proteins that effect their
production and/or activity. Aminoacyl synthetases are involved in
"charging" a tRNA molecule, i.e., attaching a tRNA to its cognate
amino acid. (Martinis et al., Aminoacyl-tRNA Synthetases: General
Features and Relationships. Chapter 58 in: Escherichia coli and
Salmonella typhimurium: Cellular and Molecular Biology, 2nd Ed.,
Neidhardt, Frederick C., Editor in Chief, American Society for
Microbiology, Washington, D.C., 1996, Volume 1, pages 887-901) and
references cited therein; (Grunberg-Manago, Regulation of the
Expression of Aminoacyl-tRNA Synthetases and Translation. Chapter
91 in: Escherichia coli and Salmonella typhimurium: Cellular and
Molecular Biology, 2nd Ed., Neidhardt, Frederick C., Editor in
Chief, American Society for Microbiology, Washington, D.C., 1996,
Volume 1, pages 1432-1457), and references cited therein; and
(Hershey, "Protein Synthesis," Chapter 40 in: Escherichia Coli and
Salmonella Typhimurium: Cellular and Molecular Biology, Neidhardt,
Frederick C., Editor in Chief, American Society for Microbiology,
Washington, D.C., 1987, Volume 1, pages 613-647), and references
cited therein.
[0341] By way of non-limiting example, manipulation of the aat gene
or gene product from E. coli, or homologs of this gene or gene
product found in other members of the Prokaryotes, Eukaryotes,
Archaebacteria and/or organelles (e.g., mitochondria, chloroplasts,
plastids and the like) may be employed to increase the efficiency
of gene expression and protein production in parent cells prior to
minicell formation and/or in segregated minicells (Bochner, B. R.
and Savageau, M.A. 1979. Inhibition of growth by imidazol(on)e
propionic acid: evidence in vivo for coordination of histidine
catabolism with the catabolism of other amino acids. Mol. Gen.
Genet. 168(1):87-95).
[0342] In addition to aat, other exemplary E. coli genes encoding
aminoacyl synthestases include alaS (act, ala-act, lovB) (Buckel et
al., Suppression of temperature-sensitive aminoacyl-tRNA synthetase
mutations by ribosomal mutations: a possible mechanism. Mol. Gen.
Genet. 149:51-61, 1976); argS (lovB) (Eriani et al., Isolation and
characterization of the gene coding for Escherichia coli
arginyl-tRNA synthetase. Nucleic Acids Res. 17:5725-36, 1989); asnS
(lcs, tss) (Yamamoto et al., Identification of a
temperature-sensitive asparaginyl-transfer ribonucleic acid
synthetase mutant of Escherichia coli. J. Bacteriol. 132:127-31,
1977); aspS (tls) (Eriani et al., Aspartyl-tRNA synthetase from
Escherichia coli: cloning and characterisation of the gene,
homologies of its translated amino acid sequence with asparaginyl-
and lysl-tRNA syntheases. Nucleic Acids Res. 18:7109-18, 1990);
cysS (Eriani et al., Cysteinyl-tRNA synthetase: determination of
the last E. coli aminoacyl-tRNA synthetase primary structure.
Nucleic Acids Res. 19:265-9, 1991); glnS (Yamao et al., Escherichia
coli glutaminyl-tRNA synthetase. I. Isolation and DNA sequence of
the glnS gene. J. Biol. Chem. 257:11639-43, 1982); gltE (Lapointe
et al., Thermosensitive mutants of Escherichia coli K-12 altered in
the catalytic Subunit and in a Regulatory factor of the
glutamy-transfer ribonucleic acid synthetase. J. Bacteriol.
122:352-8, 1975); gltM (Lapointe et al., Thermosensitive mutants of
Escherichia coli K-12 altered in the catalytic Subunit and in a
Regulatory factor of the glutamy-transfer ribonucleic acid
synthetase. J. Bacteriol. 122:352-8, 1975); gltX (Lapointe et al.,
Thermosensitive mutants of Escherichia coli K-12 altered in the
catalytic Subunit and in a Regulatory factor of the
glutamy-transfer ribonucleic acid synthetase. J. Bacteriol.
122:352-8, 1975); glyQ (glysa) (Webster et al., Primary structures
of both subunits of Escherichia coli glycyl-tRNA synthetase, J.
Biol. Chem. 252:10637-41, 1983); glyS (act, gly, glySB) (Id.); hisS
(Parker et al., Mapping hisS, the structural gene for
histidyl-transfer ribonucleic acid synthetase, in Escherichia coli.
J. Bacteriol. 138:264:7, 1979); ileS (Singer et al., Synthesis of
the isoleucyl- and valyl-tRNA synthetases and the isoleucine-valine
biosythetic enzymes in a threonine deaminase regulatory mutant of
Escherichia coli K-12. J. Mol. Biol. 175:39-55, 1984); leuS (Morgan
et al., Regulation of biosythesis of aminoacyl-transfer RNA
synthestases and of transfer-RNA in Escherichia coli. Arch. Biol.
Med. Exp. (Santiago.) 12:415-26, 1979); lysS (herC, asaD) (Clark et
al., Roles of the two lysyl-tRNA synthetases of Escherichia coli:
analysis of nucleotide sequences and mutant behavior. J. Bacteriol.
172:3237-43, 1990); lysU (Clark et al., Roles of the two lysyl-tRNA
synthetases of Escherichia coli: analysis of nucleotide sequences
and mutant behavior, J. Bacteriol. 172:3237-43, 1990); metG (Dardel
et al., Molecular cloning and primary structure of the Escherichia
coli methionyl-tRNA synthetase gene. J. Bacteriol. 160:1115-22,
1984); pheS (phe-act) (Elseviers et al., Molecular cloning and
regulation of expression of the genes for initiation factor 3 and
two aminoacyl-tRNA synthetases, J. Bacteriol. 152:357-62, 1982);
pheT (Comer et al., Genes for the alpha and beta subunits of the
phenylalanyl-transfer ribonucleic acid synthetase of Escherichia
coli. J. Bacteriol. 127:923-33, 1976); proS (drp) (Bohman et al., A
temperature-sensitive mutant in prolinyl-tRNA ligase of Escherichia
coli K-12 Mo. Gen. Genet. 177:603-5, 1980); serS (Hartlein et al.,
Cloning and characterization of the gene for Escherichia coli
seryl-tRNA synthetase. Nucleic Acids Res. 15:1005-17, 1987); thrS
(Frohler et al., Genetic analysis of mutations causing borrelidin
resistance by overproduction of threonyl-transfer ribonucleic acid
synthetase. J. Bacteriol. 143:1135-41, 1980); trpS (Hall et al.,
Cloning and characterization of the gene for Escherichia coli
tryptophanyl-transfer ribonucleic acid synthetase. J. Bacteriol.
148:941-9, 1981); tyrS (Buonocore et al., Properties of tyrosyl
transfer ribonucleic acid synthetase from two tyrS mutants of
Escherichia coli K-12. J. Biol. Chem. 247:4843-9, 1972); and vals
(Baer et al., Regulation of the biosynthesis of aminoacyl-transfer
ribonucleic acid synthetases and of transfer ribonucleic acid in
Escherichia coli. V. Mutants with increased levels of
valyl-transfer ribonucleic acid synthetase. J. Bacteriol.
139:165-75, 1979).
[0343] II.C.5. Regulatory Elements and Promoter Regions
[0344] Included in the design of the invention are techniques that
increase the efficiency of gene expression and protein production
in minicells. By way of non-limiting example, these techniques may
include utilization and/or modification of regulatory elements and
promoter regions. Such manipulations may result in increased or
decreased production, and/or changes in the intramolecular and
intermolecular functions, of a protein in a segregated minicell or
its parent cell prior to minicell formation; in the latter
instance, the protein may be one that is desirably retained in
segregated minicells.
[0345] The production or activity of a desired gene product may be
increased by increasing the level and/or activity of a promoter or
other regulatory region that acts to stimulate or enhance the
production of the desired gene product. The production or activity
of a desired gene product may be increased by decreasing the level
and/or activity of a promoter or other regulatory region that acts
to stimulate or enhance the production of a gene product that acts
to reduce or eliminate the level and/or activity of the desired
gene product.
[0346] II.C.5.a. Escherichia coli
[0347] Regulatory elements, promoters and other expression elements
and expression factors from E. coli include but are not limited to
acrR (Ma, D., et al. 1996. The local repressor AcrR plays a
modulating role in the regulation of acrAB genes of Escherichia
coli by global stress signals. Mol. Microbiol. 19:101-112); ampD
(Lindquist, S., et al. 1989. Signalling proteins in enterobacterial
AmpC beta-lactamase regulation. Mol. Microbiol. 3:1091-1102;
Holtje, J. V., et al. 1994. The negative regulator of
beta-lactamase induction AmpD is a N-acetyl-anhydromuramyl-L-
-alanine amidase. FEMS Microbiol. Lett. 122:159-164); appR
(Diaz-Guerra, L., et al. 1989. appk gene product activates
transcription of microcin C7 plasmid genes. J. Bacteriol.
171:2906-2908; Touati, E., et al. 1991. Are appR and katF the same
Escherichia coli gene encoding a new sigma transcription initiation
factor? Res. Microbiol. 142:29-36); appY (Atlung, T., et al. 1989.
Isolation, characterization, and nucleotide sequence of appY, a
regulatory gene for growth-phase-dependent gene expression in
Escherichia coli. J. Bacteriol. 171:1683-1691); araC (Casadaban, M.
J., et al. 1976. Regulation of the regulatory gene for the
arabinose pathway, araC. J. Mol. Biol. 104:557-566); arcA (luchi,
S., and E. C. Lin. 1988. arcA (dye), a global regulatory gene in
Escherichia coli mediating repression of enzymes in aerobic
pathways. Proc. Natl. Acad. Sci. 85:1888-1892; luchi, S., et al.
1989. Differentiation of arcA, arcB, and cpxA mutant phenotypes of
Escherichia coli by sex pilus formation and enzyme regulation. J.
Bacteriol. 171:2889-2893); argR (xerA, Rarg) (Kelln, R. A., and V.
L. Zak. 1978. Arginine regulon control in a Salmonella
typhimurium--Escherichia coli hybrid merodiploid. Mol. Gen Genet.
161:333-335; Vogel, R. H., et al. 1978. Evidence for translational
repression of arginine biosynthetic enzymes in Escherichia coli:
altered regulation in a streptomycin-resistant mutant. Mol. Gen.
Genet. 162:157-162); ascG (Hall, B. G., and L. Xu. Nucleotide
sequence, function, activation, and evolution of the cryptic asc
operon of Escherichia coli K12. Mol. Biol. Evol. 9:688-706); aslB
(Bennik, M. H., et al. 2000. Defining a rob regulon in Escherichia
coli by using transposon mutagenesis. J. Bacteriol. 182:3794-3801);
asnC (Kolling, R., and H. Lother. 1985. AsnC: an autogenously
regulated activator of asparagine synthetase A transcription in
Escherichia coli. J. Bacteriol. 164:310-315); atoC (Jenkins, L. S.,
and W. D. Nunn. 1987. Regulation of the ato operon by the atoC gene
in Escherichia coli. J. Bacteriol. 169:2096-2102); baeR (Nagasawa,
S., et al. 1993. Novel members of the two-component signal
transduction genes in Escherichia coli. J. Biochem. (Tokyo).
114:350-357); baeS (Id.1d.); barA (Nagasawa, S., et al. 1992. A
novel sensor-regulator protein that belongs to the homologous
family of signal-transduction proteins involved in adaptive
responses in Escherichia coli. Mol. Microbiol. 6:799-807; Ishige,
K., et al. 1994. A novel device of bacterial signal transducers.
EMBO J. 13:5195-5202); basS (Nagasawa, S., et al. 1993. Novel
members of the two-component signal transduction genes in
Escherichia coli. J. Biochem. (Tokyo). 114:350-357); betl (Lamark,
T., et al. 1996. The complex bet promoters of Escherichia coli:
regulation by oxygen (ArcA), choline (Betl), and osmotic stress. J.
Bacteriol. 178:1655-1662); bglG (bglC, bglS) (Schnetz, K., and B.
Rak. 1988. Regulation of the bgl operon of Escherichia coli by
transcriptional antitermination. EMBO J. 7:3271-3277; Schnetz, K.,
and B. Rak. 1990. Beta-glucoside permease represses the bgl operon
of Escherichia coli by phosphorylation of the antiterminator
protein and also interacts with glucose-specific enzyme III, the
key element in catabolite control. Proc. Natl. Acad. Sci.
87:5074-5078); birA (bioR, dhbB) (Barker, D. F., and A. M.
Campbell. 1981. Genetic and biochemical characterization of the
birA gene and its product: evidence for a direct role of biotin
holoenzyme synthetase in repression of the biotin operon in
Escherichia coli. J. Mol. Biol. 146:469-492; Barker, D. F., and A.
M. Campbell. 1981. The birA gene of Escherichia coli encodes a
biotin holoenzyme synthetase. J. Mol. Biol. 146:451-467; Howard, P.
K., et al. 1985. Nucleotide sequence of the birA gene encoding the
biotin operon repressor and biotin holoenzyme synthetase functions
of Escherichia coli. Gene. 35:321-331); btuR (Lundrigan, M. D., et
al. 1987. Separate regulatory systems for the repression of metE
and btuB by vitamin B12 in Escherichia coli. Mol. Gen. Genet.
206:401-407; Lundrigan, M. D., and R. J. Kadner. 1989. Altered
cobalamin metabolism in Escherichia coli btuR mutants affects btuB
gene regulation. J. Bacteriol. 171:154-161); cadC (Watson, N., et
al. 1992. Identification of elements involved in transcriptional
regulation of the Escherichia coli cad operon by external pH. J.
Bacteriol. 174:530-540); celD (Parker, L. L., and B. G. Hall. 1990.
Characterization and nucleotide sequence of the cryptic cel operon
of Escherichia coli K12. Genetics. 124:455-471); chaB (Berlyn, M.
K. B., et al. 1996. Linkage map of Escherichia coli K-12, Edition
9. In F. C. Neidhardt, R. Curtiss, J. L. Ingraham, E. C. C. Lin, K.
B. Low, B. Magasanik, W. S. Reznikoff, M. Riley, M. Schaechter, and
H. E. Umbarger (eds.). Escherichia coli and Salmonella typhimurium:
cellular and molecular biology, 2nd ed. American Society for
Microbiology, Washington D.C.); chaC (Berlyn, M. K. B., et al.
1996. Linkage map of Escherichia coli K-12, Edition 9. In F. C.
Neidhardt, R. Curtiss, J. L. Ingraham, E. C. C. Lin, K. B. Low, B.
Magasanik, W. S. Reznikoff, M. Riley, M. Schaechter, and H. E.
Umbarger (eds.). Escherichia coli and Salmonella typhimurium:
cellular and molecular biology, 2nd ed. American Society for
Microbiology, Washington D.C.); cpxR (Danese, P. N., et al. 1995.
The Cpx two-component signal transduction pathway of Escherichia
coli regulates transcription of the gene specifying the
stress-inducible periplasmic protease, DegP. Genes Dev. 9:387-398);
crl (Arnqvist, A., et al. 1992. The Crl protein activates cryptic
genes for curli formation and fibronectin binding in Escherichia
coli HB101. Mol. Microbiol. 6:2443-2452); cspA (Bae, W., et al.
1999. Characterization of Escherichia coli cspE, whose product
negatively regulates transcription of cspA, the gene for the major
cold shock protein. Mol. Microbiol. 31:1429-1441); cspE (Id.); csrA
(Liu, M. Y., et al. 1995. The product of the pleiotropic
Escherichia coli gene csrA modulates glycogen biosynthesis via
effects on mRNA stability. J. Bacteriol. 177:2663-2672); cynR
(Anderson, P. M., et al. 1990. The cyanase operon and cyanate
metabolism. FEMS Microbiol. Rev. 7:247-252; Sung, Y. C., and J. A.
Fuchs. 1992. The Escherichia coli K-12 cyn operon is positively
regulated by a member of the lysR family. J. Bacteriol.
174:3645-3650); cysB (Jagura-Burdzy, G., and D. Hulanicka. 1981.
Use of gene fusions to study expression of cysB, the regulatory
gene of the cysteine regulon. J. Bacteriol. 147:744-751); cytR
(Hammer-Jespersen, K., and A. Munch-Ptersen. 1975. Multiple
regulation of nucleoside catabolizing enzymes: regulation of the
deo operon by the cytR and deoR gene products. Mol. Gen. Genet.
137:327-335); dadQ (alnR) (Wild, J., and B. Obrepalska. 1982.
Regulation of expression of the dadA gene encoding D-amino acid
dehydrogenase in Escherichia coli: analysis of dadA-lac fusions and
direction of dadA transcription. Mol. Gen. Genet. 186:405-410);
dadR (alnR) (Wild, J., et al. 1985. Identification of the dadX gene
coding for the predominant isozyme of alanine racemase in
Escherichia coli K12. Mol. Gen. Genet. 198:315-322); deoR (nucR,
tsc, nupG) (Hammer-Jespersen, K., and A. Munch-Ptersen. 1975.
Multiple regulation of nucleoside catabolizing enzymes: regulation
of the deo operon by the cytR and deoR gene products. Mol. Gen.
Genet. 137:327-335); dgoR (Berlyn, M. K. B., et al. 1996. Linkage
map of Escherichia coli K-12, Edition 9. In F. C. Neidhardt, R.
Curtiss, J. L. Ingraham, E. C. C. Lin, K. B. Low, B. Magasanik, W.
S. Reznikoff, M. Riley, M. Schaechter, and H. E. Umbarger (eds.).
Escherichia coli and Salmonella typhimurium: cellular and molecular
biology, 2nd ed. American Society for Microbiology, Washington
D.C.); dicA (Bejar, S., et al. 1988. Cell division inhibition gene
dicB is regulated by a locus similar to lambdoid bacteriophage
immunity loci. Mol. Gen. Genet. 212:11-19); dnaK (gro, groP,
groPAB, groPC, groPF, grpC, grpF, seg) (Bochner, B. R., et al.
1986. Escherichia coli DnaK protein possesses a 5'-nucleotidase
activity that is inhibited by AppppA. J. Bacteriol. 168:931-935);
dniR (Kajie, S., et al. 1991. Molecular cloning and DNA sequence of
dniR, a gene affecting anaerobic expression of the Escherichia coli
hexaheme nitrite reductase. FEMS Microbiol. Lett. 67:205-211); dsdC
(Heincz, M. C., and E. McFall. 1978. Role of the dsdC activator in
regulation of D-serine deaminase synthesis. J. Bacteriol.
136:96-103); ebgR (Hall, B. G., and N. D. Clarke. 1977. Regulation
of newly evolved enzymes. III Evolution of the ebg repressor during
selection for enhanced lactase activity. Genetics. 85:193-201);
envy (Lundrigan, M. D., and C. F. Earhart. 1984. Gene envY of
Escherichia coli K-12 affects thermoregulation of major porin
expression. J. Bacteriol. 157:262-268); envZ (ompB, perA, tpo)
(Russo, F. D, and T. J. Silhavy. 1991. EnvZ controls the
concentration of phosphorylated OmpR to mediate osmoregulation of
the porin genes. J. Mol. Biol. 222:567-580); evgA (Nishino, K., and
A. Yamaguichi. 2001. Overexpression of the response regulator evgA
of the two-component signal transduction system modulates multidrug
resistance conferred by multidrug resistance transporters. J.
Bacteriol. 183:1455-1458); evgS (Id.); exuR (Portalier, R., et al.
1980. Regulation of Escherichia coli K-12 hexuronate system genes:
exu regulon. J. Bacteriol. 143:1095-1107); fadR (dec, ole, thdB)
(Simons, R. W., et al. 1980. Regulation of fatty acid degradation
in Escherichia coli: isolation and characterization of strains
bearing insertion and temperature-sensitive mutations in gene fadR.
J. Bacteriol. 142:621-632); fecI (Van Hove, B., et al. 1990. Novel
two-component transmembrane transcription control: regulation of
iron dicitrate transport in Escherichia coli K-12. J. Bacteriol.
172:6749-6758); fecR (Id.); fhlA (Maupin, J. A., and K. T.
Shanmugam. 1990. Genetic regulation of formate hydrogenlyase of
Escherichia coli: role of the fhlA gene product as a
transcriptional activator for a new regulatory gene, fhlB. J.
Bacteriol. 172:4798-4806; Rossmann, R., et al. 1991. Mechanism of
regulation of the formate-hydrogenlyase pathway by oxygen, nitrate,
and pH: definition of the formate regulon. Mol. Microbiol.
5:2807-2814); fhlB (Maupin, J. A., and K. T. Shanmugam. 1990.
Genetic regulation of formate hydrogenlyase of Escherichia coli:
role of the fhlA gene product as a transcriptional activator for a
new regulatory gene, fhlB. J. Bacteriol. 172:4798-4806); fimB (pil)
(Pallesen, L., et al. 1989. Regulation of the phase switch
controlling expression of type 1 fimbriae in Escherichia coli. Mol.
Microbiol. 3:925-931); fimE (pilH) (Id.); flhC (flaI) (Liu, X., and
P. Matsumura. 1994. The FlhD/FlhC complex, a transcriptional
activator of the Escherichia coli flagellar class II operons. J.
Bacteriol. 176:7345-7351); flhD (flhB) (Id.); fliA (flaD, rpof)
(Komeda, Y., et al. 1986. Transcriptional control of flagellar
genes in Escherichia coli K-12. J. Bacteriol. 168:1315-1318); fnr
(frdB, nirA, nirR) (Jones, H. M., and R. P. Gunsalus. 1987.
Regulation of Escherichia coli fumarate reductase (frdABCD) operon
expression by respiratory electron acceptors and the fnr gene
product. J. Bacteriol. 169:3340-3349); fruR (fruC, shl) (Geerse, R.
H., at al. The PEP: fructose phosphotransferase system in
Salmonella typhimurium: FPr combines enzyme IIIFru and pseudo-HPr
activities. Mol. Gen. Genet. 216:517-525); fucR (Zhu, Y., and E. C.
Lin. 1986. An evolvant of Escherichia coli that employs the
L-fucose pathway also for growth on L-galactose and D-arabinose. J.
Mol. Evol. 23:259-266); fur (Bagg, A., and J. B. Neilands. 1987.
Ferric uptake regulation protein acts as a repressor, employing
iron (II) as a cofactor to bind the operator of an iron transport
operon in Escherichia coli. Biochemistry 26:5471-5477); gadR gene
product from Lactococcus lactis (Sanders, J. W., et al. 1997. A
chloride-inducible gene expression cassette and its use in induced
lysis of Lactococcus lactis. Appl. Environ. Microbiol.
63:4877-4882); galR (von Wilcken-Bergmann, B., and B. Muller-Hill.
1982. Sequence of galR gene indicates a common evolutionary origin
of lac and gal repressor in Escherichia coli. Proc. Natl. Acad.
Sci. 79:2427-2431); galS (mglD) (Weickert., M. J., and S. Adhya.
1992. Isorepressor of the gal regulon in Escherichia coli. J. Mol.
Biol. 226:69-83); galU (Berlyn, M. K. B., et al. 1996. Linkage map
of Escherichia coli K-12, Edition 9. In F. C. Neidhardt, R.
Curtiss, J. L. Ingraham, E. C. C. Lin, K. B. Low, B. Magasanik, W.
S. Reznikoff, M. Riley, M. Schaechter, and H. E. Umbarger (eds.).
Escherichia coli and Salmonella typhimurium: cellular and molecular
biology, 2nd ed. American Society for Microbiology, Washington
D.C.); gatR (Nobelmann, B., and J. W. Lengeler. 1996. Molecular
analysis of the gat genes from Escherichia coli and of their roles
in galactitol transport and metabolism. J. Bacteriol.
178:6790-6795); gcvA (Wilson, R. L., et al. 1993. Positive
regulation of the Escherichia coli glycine cleavage enzyme system.
J. Bacteriol. 175:902-904); glgS (Hengge-Aronis, R., et al. 1993.
Osmotic regulation of rpoS-dependent genes in Escherichia coli. J.
Bacteriol. 175:259-265; Yang, H., et al. 1996. Coordinate genetic
regulation of glycogen catabolism and biosynthesis in Escherichia
coli via the CsrA gene product. J. Bactgeriol. 178:1012-1017); glnB
(Bueno, R., et al. 1985. Role of glnB and glnD gene products in
regulation of the glnALG operon of Escherichia coli. J. Bacteriol.
164:816-822); glnG (gln, ntrC) (Pahel, G., and B. Tyler. 1979. A
new glnA-linked regulatory gene for glutamine synthetase in
Escherichia coli. Proc. Natl. Acad. Sci. 76:4544-4548); glnL (glnR,
ntrB) (MacNeil, T., et al. The products of glnL and glnG are
bifunctional regulatory proteins. Mol. Gen. Genet. 188:325-333);
glpR (Silhavy, T. J., et al. 1976. Periplasmic protein related to
the sn-glycerol-3-phosphate transport system of Escherichia coli.
J. Bacteriol. 126:951-958); gltF (Castano, I., et al. gltF, a
member of the gltBDF operon of Escherichia coli, is involved in
nitrogen-regulated gene expression. Mol. Microbiol. 6:2733-2741);
gntR (Peekhaus, N., and T. Conway. 1998. Positive and negative
transcriptional regulation of the Escherichia coli gluconate
regulon gene gntT by GntR and the cyclic AMP (cAMP)-cAMP receptor
protein complex. J. Bacteriol. 180:1777-1785); hha (Neito, J. M.,
et al. The hha gene modulates haemolysin expression in Escherichia
coli. Mol. Microbiol. 5:1285-1293); himD (hip) (Goosen, N., et al.
1984. Regulation of Mu transposition. II. The Escherichia coli HimD
protein positively controls two repressor promoters and the early
promoter of bacteriophage Mu. Gene. 32:419-426); hrpB gene product
from Pseudomonas solanacearum (Van Gijsegem, F., et al. 1995. The
hrp gene locus of Pseudomonas solanacearum, which controls the
production of a type III secretion system, encodes eight proteins
related to components of the bacterial flagellar biogenesis
complex. Mol. Microbiol. 15:1095-1114); hybF (Berlyn, M. K. B., et
al. 1996. Linkage map of Escherichia coli K-12, Edition 9. In F. C.
Neidhardt, R. Curtiss, J. L. Ingraham, E. C. C. Lin, K. B. Low, B.
Magasanik, W. S. Reznikoff, M. Riley, M. Schaechter, and H. E.
Umbarger (eds.). Escherichia coli and Salmonella typhimurium:
cellular and molecular biology, 2nd ed. American Society for
Microbiology, Washington D.C.); hycA (Hopper, S., et al. 1994.
Regulated expression in vitro of genes coding for formate
hydrogenlyase components of Escherichia coli. J. Biol. Chem.
269:19597-19604); hydG (Leonhartsberger, S. et al. 2001. The hydH/G
genes from Escherichia coli code for a zinc and lead responsive
two-component regulatory system. J. Mol. Biol. 307:93-105); hydH
(Id.); iciA (Thony, B., et al. 1991. iciA, an Escherichia coli gene
encoding a specific inhibitor of chromosomal initiation of
replication in vitro. Proc. Natl. Acad. Sci. 88:4066-4070); iclR
(Maloy, S. R., and W. D. Nunn. 1982. Genetic regulation of the
glyoxylate shunt in Escherichia coli K-12. J. Bacteriol.
149:173-180); ileR (avr, flrA) (Johnson, D. I., and R. L.
Somerville. 1984. New regulatory genes involved in the control of
transcription initiation at the thr and ilv promoters of
Escherichia coli K-12. Mol. Gen. Genet. 195:70-76); ilvR (Id.);
ilvU (Fayerman, J. T., et al. 1979. ilvU, a locus in Escherichia
coli affecting the derepression of isoleucyl-tRNA synthetase and
the RPC-5 chromatographic profiles of tRNAIle and tRNAVal. J. Bio.
Chem. 254:9429-9440); ilvY (Wek, R. C., and G. W. Hatfield. 1988.
Transcriptional activation at adjacent operators in the
divergent-overlapping ilvY and ilvC promoters of Escherichia coli.
J. Mol. Biol. 203:643-663); inaA (White, S., et al. 1992. pH
dependence and gene structure of inaA in Escherichia coli. J.
Bacteriol. 174:1537-1543); inaR (Id.); kdgR (Nemoz, G., et al.
1976. Physiological and genetic regulation of the aldohexuronate
transport system in Escherichia coli. J. Bacteriol. 127:706-718);
ladI (Riggs, A.
D, and S. Bourgeois. 1968. On the assay, isolation and
characterization of the lac repressor. J. Mol. Biol. 34:361-364);
leuO (Shi, X., and G. N. Bennett. 1995. Effects of multicopy LeuO
on the expression of the acid-inducible lysine decarboxylase gene
in Escherichia coli. J. Bacteriol. 177:810-814; Klauck, E., et al.
1997. The LysR-like regulator LeuO in Escherichia coli is involved
in the translational regulation of rpoS by affecting the expression
of the small regulatory DsrA-RNA. Mol. Microbiol. 25:559-569); leuR
(Theall, G., et al. 1979. Regulation of the biosynthesis of
aminoacyl-tRNA synthetases and of tRNA in Escherichia coli. IV.
Mutants with increased levels of leucyl- or seryl-tRNA synthetase.
Mol. Gen. Genet. 169:205-21 1); leuY (Morgan, S., et al. 1979.
Regulation of biosynthesis of aminoacyl-transfer RNA synthetases
and of transfer-RNA in Escherichia coli. Arch. Biol. Med. Exp.
(Santiago) 12:415-426); lexA (Mount, D. W. 1977. A mutant of
Escherichia coli showing constitutive expression of the lysogenic
induction and error-prone DNA repair pathways. Proc. Natl. Acad.
Sci. 74:300-304; Little, J. W., et al. 1980. Cleavage of the
Escherichia coli lexA protein by the recA protease. Proc. Natl.
Acad. Sci. 77:3225-3229); lldR (lctR) (Dong, J. M., et al. 1993.
Three overlapping lct genes involved in L-lactate utilization by
Escherichia coli. J. Bacteriol. 175:6671-6678) lpp (Brosius, J.
Expression vectors employing lambda-, trp-, lac-, and lpp-derived
promoters. 1988. Biotechnology. 10:205-225); lrhA (genR)
(Bongaerts, J., et al. 1995. Transcriptional regulation of the
proton translocating NADH dehydrogenase genes (nuoA-N) of
Escherichia coli by electron acceptors, electron donors and gene
regulators. Mol. Microbiol. 16:521-534); lrp (ihb, livR, lss, lstR,
oppI, rblA, mbf) (Ito, K., et al. Multiple control of Escherichia
coli lysyl-tRNA synthetase expression involves a transcriptional
repressor and a translational enhancer element. Proc. Natl. Acad.
Sci. 90:302-306); lysR (Gicquel-Sanzey, B. and P. Cossart. 1982.
Homologies between different procaryotic DNA-binding regulatory
proteins and between their sites of action. EMBO J. 1:591-595;
Stragier, P., et al. 1983. Regulation of diaminopimelate
decarboxylase synthesis in Escherichia coli. II. Nucleotide
sequence of the lysA gene and its regulatory region. J. Mol. Biol.
168:321-331); malI (Reidl, J., et al. 1989. MalI, a novel protein
involved in regulation of the maltose system of Escherichia coli,
is highly homologous to the repressor proteins GalR, CytR, and
LacI. J. Bacteriol. 171:4888-4499); malT (malA) (Bebarbouille, M.,
and M. Schwartz. Mutants which make more malT product, the
activator of the maltose regulon in Escherichia coli. Mol. Gen.
Genet. 178:589-595); marA (cpxb, soxQ) (Ariza, R. R., et al.
Repressor mutations in the marRAB operon that activate oxidative
stress genes and multiple antibiotic resistance in Escherichia
coli. J. Bacteriol. 176: 143-148); marB (Berlyn, M. K. B., et al.
1996. Linkage map of Escherichia coli K-12, Edition 9. In F. C.
Neidhardt, R. Curtiss, J. L. Ingraham, E. C. C. Lin, K. B. Low, B.
Magasanik, W. S. Reznikoff, M. Riley, M. Schaechter, and H. E.
Umbarger (eds.). Escherichia coli and Salmonella typhimurium:
cellular and molecular biology, 2nd ed. American Society for
Microbiology, Washington D.C.); marR (Ariza, R. R., et al.
Repressor mutations in the marRAB operon that activate oxidative
stress genes and multiple antibiotic resistance in Escherichia
coli. J. Bacteriol. 176:143-148); melR (Williams, J., et al. 1994.
Interactions between the Escherichia coli MelR transcription
activator protein and operator sequences at the melAB promoter.
Biochem. J. 300:757-763); metJ (Smith, A. A., et al. 1985.
Isolation and characterization of the product of the
methionine-regulatory gene metJ of Escherichia coli K-12. Proc.
Natl. Acad. Sci. 82:6104-6108; Shoeman, R., et al. 1985. Regulation
of methionine synthesis in Escherichia coli: effect of metJ gene
product and S-adenosylmethionine on the in vitro expression of the
metB, metL and metJ genes. Biochem. Biophys. Res. Commun.
133:731-739); metR (Maxon, M. E., et al. 1989. Regulation of
methionine synthesis in Escherichia coli: effect of the MetR
protein on the expression of the metE and metR genes. Proc. Natl.
Acad. Sci. 86:85-89); mglR (R-MG) (Berlyn, M. K. B., et al. 1996.
Linkage map of Escherichia coli K-12, Edition 9. In F. C.
Neidhardt, R. Curtiss, J. L. Ingraham, E. C. C. Lin, K. B. Low, B.
Magasanik, W. S. Reznikoff, M. Riley, M. Schaechter, and H. E.
Umbarger (eds.). Escherichia coli and Salmonella typhimurium:
cellular and molecular biology, 2nd ed. American Society for
Microbiology, Washington D.C.); mhpR (Ferrandez, A., et al. 1997.
Genetic characterization and expression in heterologous hosts of
the 3-(3-hydroxyphenyl)propionate catabolic pathway of Escherichia
coli K-12. J. Bacteriol. 179:2573-2581); mhpS (Berlyn, M. K. B., et
al. 1996. Linkage map of Escherichia coli K-12, Edition 9. In F. C.
Neidhardt, R. Curtiss, J. L. Ingraham, E. C. C. Lin, K. B. Low, B.
Magasanik, W. S. Reznikoff, M. Riley, M. Schaechter, and H. E.
Umbarger (eds.). Escherichia coli and Salmonella typhimurium:
cellular and molecular biology, 2nd ed. American Society for
Microbiology, Washington D.C.); micF (stc) (Aiba, H., et al. 1987.
Function of micF as an antisense RNA in osmoregulatory expression
of the ompF gene in Escherichia coli. J. Bacteriol. 169:3007-3012);
mprA (emrR) (del Castillo, I., et al. 1990. mprA, an Escherichia
coli gene that reduces growth-phase-dependent synthesis of
microcins B17 and C7 and blocks osmoinduction of proU when cloned
on a high-copy-number plasmid. J. Bacteriol. 172:437-445); mtlR
(Figge, R. M., et al. 1994. The mannitol repressor (MtlR) of
Escherichia coli. J. Bacteriol. 176:840-847); nagC (nagR)
(Plumbridge, J. A. 1991. Repression and induction of the nag
regulon of Escherichia coli K-12: the roles of nagC and nagA in
maintenance of the uninduced state. Mol. Microbiol. 5:2053-3062);
narL (frdR, narR) (Stewart, V. 1982. Requirement of Fnr and NarL
functions for nitrate reductase expression in Escherichia coli
K-12. J. Bacteriol. 151:1320-1325; Miller, J. B., et al. 1987.
Molybdenum-sensitive transcriptional regulation of the chlD locus
of Escherichia coli. J. Bacteriol. 169:1853-1860; luchi, S., and E.
C. Lin. 1987. Molybdenum effector of fumarate reductase repression
and nitrate reductase induction in Escherichia coli. J. Bacteriol.
169:3720-3725); narP (Rabin, R. S., and V. Stewart. 1993. Dual
response regulators (NarL and NarP) interact with dual sensors
(NarX and NarQ) to control nitrate- and nitrite-regulated gene
expression in Escherichia coli K-12. J. Bacteriol. 175:3259-3268);
nhaR (gene product from E. coli (Rahav-Manor, O., et al. 1992.
NhaR, a protein homologous to a family of bacterial regulatory
proteins (LysR), regulates nhaA, the sodium proton antiporter gene
in Escherichia coli. J. Biol. Chem. 267:10433-10438); ompR (cry,
envZ, ompB) (Taylor, R. K., et al. Identification of OmpR: a
positive regulatory protein controlling expression of the major
outer membrane matrix porin proteins of Escherichia coli K-12. J.
Bacteriol. 147:255-258); oxyR (mor, momR) (VanBogelen, R. A, et al.
1987. Differential induction of heat shock, SOS, and oxidation
stress regulons and accumulation of nucleotides in Escherichia
coli. J. Bacteriol. 169:26-32); pdhR (Haydon, D. J., et al. A
mutation causing constitutive synthesis of the pyruvate
dehydrogenase complex in Escherichia coli is located within the
pdhR gene. FEBS Lett. 336:43-47); phnF (Wanner, B. L., and W. W.
Metcalf. 1992. Molecular genetic studies of a 10.9-kb operon in
Escherichia coli for phosphonate uptake and biodegradation. FEMS
Microbiol. Lett. 79:133-139); phoB (phoRc, phoT) (Pratt, C. 1980.
Kinetics and regulation of cell-free alkaline phosphatase
synthesis. J. Bacteriol. 143:1265-1274); phoP (Kasahara, M., et al.
1992. Molecular analysis of the Escherichia coli phoP-phoQ operon.
J. Bacteriol. 174:492-498); phoQ (Id.); phoR (Rlpho, nmpB, phoR1)
(Bracha, M., and E. Yagil. 1969. Genetic mapping of the phoR
regulator gene of alkaline phosphatase in Escherichia coli. J. Gen.
Microbiol. 59:77-81); phoU (phoT) (Nakata, A., et al. 1984.
Regulation of the phosphate regulon in Escherichia coli K-12:
regulation of the negative regulatory gene phoU and identification
of the gene product. J. Bacteriol. 159:979-985); poaR (Berlyn, M.
K. B., et al. 1996. Linkage map of Escherichia coli K-12, Edition
9. In F. C. Neidhardt, R. Curtiss, J. L. Ingraham, E. C. C. Lin, K.
B. Low, B. Magasanik, W. S. Reznikoff, M. Riley, M. Schaechter, and
H. E. Umbarger (eds.). Escherichia coli and Salmonella typhimurium:
cellular and molecular biology, 2nd ed. American Society for
Microbiology, Washington D.C.); poxA (Chang, Y. Y., and J. E.
Cronan Jr. 1982. Mapping nonselectable genes of Escherichia coli by
using transposon Tn10: location of a gene affecting pyruvate
oxidase. J. Bacteriol. 151:1279-1289); proQ (Milner, J. L., and J.
M. Wood. 1989. Insertion proQ220::Tn5 alters regulation of proline
porter II, a transporter of proline and glycine betaine in
Escherichia coli. J. Bacteriol. 171:947-951); pspA (Weiner, L., et
al. 1991. Stress-induced expression of the Escherichia coli phage
shock protein operon is dependent on sigma 54 and modulated by
positive and negative feedback mechanisms. Genes Dev. 5:1912-1923);
pspB (Weiner, L., et al. 1991. Stress-induced expression of the
Escherichia coli phage shock protein operon is dependent on sigma
54 and modulated by positive and negative feedback mechanisms.
Genes Dev. 5:1912-1923); pspC (Weiner, L., et al. 1991.
Stress-induced expression of the Escherichia coli phage shock
protein operon is dependent on sigma 54 and modulated by positive
and negative feedback mechanisms. Genes Dev. 5:1912-1923); pssR
(Sparrow, C. P., and C. R. Raetz. 1983. A transacting regulatory
mutation that causes overproduction of phosphatidylserine synthase
in Escherichia coli. J. Biol. Chem. 258:9963-9967); purR (Meng, L.
M., et al. 1990. Autoregulation of PurR repressor synthesis and
involvement of purR in the regulation of purB, purC, purL, purMN
and guaBA expression in Escherichia coli. Eur. J. Biochem.
187:373-379); putA (poaA) gene product from Salmonella enterica
serotype Typhimurium (Menzel, R., and J. Roth. 1981. Regulation of
the genes for proline utilization in Salmonella typhimurium:
autogenous repression by the putA gene product. J. Mol. Biol.
148:21-44); pyrI (Cunin, R., et al. 1985. Structure-function
relationship in allosteric aspartate carbamoyltransferase from
Escherichia coli. I. Primary structure of a pyrI gene encoding a
modified regulatory subunit. J. Mol. Biol. 186:707-713); rbsR
(Lopilato, J. E., et al. 1984. D-ribose metabolism in Escherichia
coli K-12: genetics, regulation, and transport. J. Bacteriol.
158:665-673); rcsA (Gottesman, S., et al. 1985. Regulation of
capsular polysaccharide synthesis in Escherichia coli K-12:
characterization of three regulatory genes. J. Bacteriol.
162:1111-1119); rcsB (Id.); rcsC (Id.); rcsF (Grevais, F. G., and
G. R. Drapeau. 1992. Identification, cloning, and characterization
of rcsF, a new regulator gene for exopolysaccharide synthesis that
suppresses the division mutation ftsZ84 in Escherichia coli K-12.
J. Bacteriol. 174:8016-8022); relB (Christensen, S. K., et al.
2001. RelE, a global inhibitor of translation, is activated during
nutritional stress. Proc Natl. Acad. Sci. 98:14328-14333); rfaH
(sfrB) (Pradel, E., and C. A. Schnaitman. 1991. Effect of rfaH
(sfrB) and temperature on expression of rfa genes of Escherichia
coli K-12. J. Bacteriol. 173:6428-6431); rhaR (Tobin, J. F., and R.
F. Schleif. 1987. Positive regulation of the Escherichia coli
L-rhamnose operon is mediated by the products of tandemly repeated
regulatory genes. J. Mol. Biol. 196:789-799); rhaS (Id.); rnk
(Berlyn, M. K. B., et al. 1996. Linkage map of Escherichia coli
K-12, Edition 9. In F. C. Neidhardt, R. Curtiss, J. L. Ingraham, E.
C. C. Lin, K. B. Low, B. Magasanik, W. S. Reznikoff, M. Riley, M.
Schaechter, and H. E. Umbarger (eds.). Escherichia coli and
Salmonella typhimurium: cellular and molecular biology, 2nd ed.
American Society for Microbiology, Washington D.C.); rob (Skarstad,
K., et al. A novel binding protein of the origin of the Escherichia
coli chromosome. J. Biol. Chem. 268:535-5370); rseA (mclA)
(Missiakas, D., et al. 1997. Modulation of the Escherichia coli
sigmaE (RpoE) heat-shock transcription-factor activity by the RseA,
RseB and RseC proteins. Mol. Microbiol. 24:355-371; De Las Penas,
A. 1997. The sigmaE-mediated response to extracytoplasmic stress in
Escherichia coli is transduced by RseA and RseB, two negative
regulators of sigmaE. Mol. Microbiol. 24:373-385); rseB (Id.); rseC
(Id.); rspA (Huisman, G. W., and T. Kolter. 1994. Sensing
starvation: a homoserine lactone--dependent signaling pathway in
Escherichia coli. Science. 265:537-539); rspB (Shafqat, J., et al.
An ethanol-inducible MDR ethanol dehydrogenase/acetaldehyde
reductase in Escherichia coli: structural and enzymatic
relationships to the eukaryotic protein forms. Eur. J. Biochem.
263:305-311); rssA (Berlyn, M. K. B., et al. 1996. Linkage map of
Escherichia coli K-12, Edition 9. In F. C. Neidhardt, R. Curtiss,
J. L. Ingraham, E. C. C. Lin, K. B. Low, B. Magasanik, W. S.
Reznikoff, M. Riley, M. Schaechter, and H. E. Umbarger (eds.).
Escherichia coli and Salmonella typhimurium: cellular and molecular
biology, 2nd ed. American Society for Microbiology, Washington
D.C.); rssB (Muffler, A., et al. 1996. The response regulator RssB
controls stability of the sigma(S) subunit of RNA polymerase in
Escherichia coli. EMBO J. 15:1333-1339); sbaA (Berlyn, M. K. B., et
al. 1996. Linkage map of Escherichia coli K-12, Edition 9. In F. C.
Neidhardt, R. Curtiss, J. L. Ingraham, E. C. C. Lin, K. B. Low, B.
Magasanik, W. S. Reznikoff, M. Riley, M. Schaechter, and H. E.
Umbarger (eds.). Escherichia coli and Salmonella typhimurium:
cellular and molecular biology, 2nd ed. American Society for
Microbiology, Washington D.C.); sdaC (Id.); sdiA (Sitnikov, D. M.,
et al. 1996. Control of cell division in Escherichia coli:
regulation of transcription of I involves both rpoS and
SdiA-mediated autoinduction. Proc. Natl. Acad. Sci. 93:336-341);
serR (Theall, G., et al . 1979. Regulation of the biosynthesis of
aminoacyl-tRNA synthetases and of tRNA in Escherichia coli. IV.
Mutants with increased levels of leucyl- or seryl-tRNA synthetase.
Mol. Gen. Genet. 169:205-211); sfsA (Takeda, K., et al. 2001.
Effects of the Escherichia coli sfsA gene on mal genes expression
and a DNA binding activity of SfsA. Biosci. Biotechnol. Biochem.
65:213-217); sfsB (nlp, sfsl) (Berlyn, M. K. B., et al. 1996.
Linkage map of Escherichia coli K-12, Edition 9. In F. C.
Neidhardt, R. Curtiss, J. L. Ingraham, E. C. C. Lin, K. B. Low, B.
Magasanik, W. S. Reznikoff, M. Riley, M. Schaechter, and H. E.
Umbarger (eds.). Escherichia coli and Salmonella typhimurium:
cellular and molecular biology, 2nd ed. American Society for
Microbiology, Washington D.C.); soxR (Tsaneva, I. R., and B. Weiss.
1990. soxR, a locus governing a superoxide response regulon in
Escherichia coli K-12. J. Bacteriol. 172:4197-4205); soxS (Wu, J.,
and B. Weiss. 1991. Two divergently transcribed genes, soxR and
soxS, control a superoxide response regulon of Escherichia coli. J.
Bacteriol. 173:2864-2871); srlR (gutR) (Csonka, L. N., and A. J.
Clark. 1979. Deletions generated by the transposon Tn10 in the srl
recA region of the Escherichia coli K-12 chromosome. Genetics.
93:321-343); tdcA (Ganduri, Y. L., et al. 1993. TdcA, a
transcriptional activator of the tdcABC operon of Escherichia coli,
is a member of the LysR family of proteins. Mol. Gen. Genet.
240:395-402); tdcR (Hagewood, B. T., et al. 1994. Functional
analysis of the tdcABC promoter of Escherichia coli: roles of TdcA
and TdcR. J. Bacteriol. 176:6241-6220); thrS (Springer, M., et al.
1985. Autogenous control of Escherichia coli threonyl-tRNA
synthetase expression in vivo. J. Mol. Biol. 185:93-104); torR
(Simon, G., et al. 1994. The torR gene of Escherichia coli encodes
a response regulator protein involved in the expression of the
trimethylamine N-oxide reductase genes. J. Bacteriol.
176:5601-5606); treR (Horlacher, R., and W. Boos. 1997.
Characterization of TreR, the major regulator of the Escherichia
coli trehalose system. J. Biol. Chem. 272:13026-13032); trpR
(Gunsalus, R. P., and C. Yanofsky. 1980. Nucleotide sequence and
expression of Escherichia coli trpR, the structural gene for the
trp aporepressor. Proc. Natl. Acad. Sci. 77:7117-7121); tyrR
(Camakaris, H., and J. Pittard. 1973. Regulation of tyrosine and
phenylalanine biosynthesis in Escherichia coli K-12: properties of
the tyrR gene product. J. Bacteriol. 115:1135-1144); uhpA (Kadner,
R. J., and D. M. Shattuck-Eidens. 1983. Genetic control of the
hexose phosphate transport system of Escherichia coli: mapping of
deletion and insertion mutations in the uhp region. J. Bacteriol.
155:1052-1061); uidR (gusR) (Novel, M., and G. Novel. 1976.
Regulation of beta-glucuronidase synthesis in Escherichia coli
K-12: pleiotropic constitutive mutations affecting uxu and uidA
expression. J. Bacteriol. 127:418-432); uspA (Berlyn, M. K. B., et
al. 1996. Linkage map of Escherichia coli K-12, Edition 9. In F. C.
Neidhardt, R. Curtiss, J. L. Ingraham, E. C. C. Lin, K. B. Low, B.
Magasanik, W. S. Reznikoff, M. Riley, M. Schaechter, and H. E.
Umbarger (eds.). Escherichia coli and
Salmonella typhimurium: cellular and molecular biology, 2nd ed.
American Society for Microbiology, Washington D.C.); uxuR (Novel,
M., and G. Novel. 1976. Regulation of beta-glucuronidase synthesis
in Escherichia coli K-12: pleiotropic constitutive mutations
affecting uxu and uidA expression. J. Bacteriol. 127:418-432); wrbA
(Yang, W., et al. 1993. A stationary-phase protein of Escherichia
coli that affects the mode of association between the trp repressor
protein and operator-bearing DNA. Proc. Natl. Acad. Sci.
90:5796-5800); xapR (pndR) (Seeger, C., et al. 1995. Identification
and characterization of genes (xapA, xapB, and xapR) involved in
xanthosine catabolism in Escherichia coli. J. Bacteriol.
177:5506-5516); and xylR (Inouye, S., et al. 1987. Expression of
the regulatory gene xylS on the TOL plasmid is positively
controlled by the xylR gene product. Proc. Natl. Acad. Sci.
84:5182-5186);
[0348] Regulatory elements, promoters and other expression elements
and factors from prokaryotes other than E. coli and B. substilis
include without limitation ahyRI gene product from Aeromonas
hydrophila and Aeromonas salmomicida (Swift, S., et al. 1997.
Quorum sensing in Aeromonas hydrophila and Aeromonas salmomicida:
identification of the LuxRI homologs AhyRI and AsaRI and their
cognate N-acylhomoserine lactone signal molecules. J. Bacteriol.
179:5271-5281); angR gene product from Vibrio anguillarum (Salinas,
P. C., et al. 1989. Regulation of the iron uptake system in Vibrio
anguillarum: evidence for a cooperative effect between two
transcriptional activators. Proc. Natl. Acad. Sci. 86:3529-3522);
aphA gene product from Vibrio cholerae (Kovacikova, G., and K.
Skorupski. 2001. Overlapping binding sites for the virulence gene
regulators AphA, AphB and cAMP-CRP at the Vibrio cholerae tcpPH
promoter. Mol. Microbiol. 41:393-407); aphB gene product from
Vibrio cholerae (Kovachikova, G., and K. Skorupski. 2000.
Differential activation of the tcpPH promoter by AphB determines
biotype specificity of virulence gene expression in Vibrio
cholerae. J. Bacteriol. 182:3228-3238); comE gene product from
Streptococcus pneumoniae (Ween, O., et al. 1999. Identification of
DNA binding sites for ComE, a key regulator of natural competence
in Streptococcus pneumoniae. Mol. Microbiol. 33:817-827); esaI gene
product from Pantoea stewartii subsp. stewartii (von Bodman, S. B.,
et al. 1998. A negative regulator mediates quorum-sensing control
of exopolysaccharide production in Pantoea stewartii subsp.
stewartii. Proc. Natl. Acad. Sci. 95:7687-7692); esaR gene product
from Pantoea stewartii subsp. stewartii (Id.); expI gene product
from Erwinia chrysanthemi (Nasser, W., et al. 1998.
Characterization of the Erwinia chrysanthemi expI-expR locus
directing the synthesis of two N-acyl-homoserine lactone signal
molecules. Mol. Microbiol. 29:1391-1405); expR gene product from
Erwinia chrysanthemi (Id.); gacA gene product from Pseudomonas
aeruginosa (Pessi, G., and D. Haas. 2001. Dual control of hydrogen
cyanide biosynthesis by the global activator GacA in Pseudomonas
aeruginosa PAO1. FEMS Microbiol. Lett. 200:73-78); hapR gene
product from Vibrio cholerae (Jobling, M. G., and R. K. Holmes.
Characterization of hapR, a positive regulator of the Vibrio
cholerae HA/protease gene hap, and its identification as a
functional homologue of the Vibrio harveyi luxR gene. Mol.
Microbiol. 26:1023-1034); hlyR gene product from Vibrio cholerae
(von Mechow, S., et al. 1985. Mapping of a gene that regulates
hemolysin production in Vibrio cholerae. J. Bacteriol.
163:799-802); hupR gene product from Vibrio vulnificus (Litwin, C.
M., and J. Quackenbush. 2001. Characterization of a Vibrio
vulnificus LysR homologue, HupR, which regulates expression of the
haem uptake outer membrane protein, HupA. Microb. Pathog.
31:295-307); lasR gene product from Pseudomonas aerugenosa
(Gambella, M. J., and B. H. Igleweski. 1991. Cloning and
characterization of the Pseudomonas aeruginosa lasR gene, a
transcriptional activator of elastase expression. J. Bacteriol.
173:3000-3009); leuO gene product from Salmonella enterica serovar
Typhimurium (Fang, M., and H. Y. Wu. 1998. A promoter relay
mechanism for sequential gene activation. J. Bacteriol.
180:626-633); luxI gene product from Vibrio cholerae (Engebrecht,
J., and M. Silverman. Nucleotide sequence of the regulatory locus
controlling expression of bacterial genes for bioluminescence.
Nucleic Acids Res. 15:10455-10467); luxO gene product from Vibrio
cholerae (Bassler, B. L., et al. 1994. Sequence and function of
LuxO, a negative regulator of luminescence in Vibrio harveyi. Mol.
Microbiol. 12:403-412); luxR gene product from Vibrio cholerae
(Engebrecht, J., and M. Silverman. Nucleotide sequence of the
regulatory locus controlling expression of bacterial genes for
bioluminescence. Nucleic Acids Res. 15:10455-10467); phzR gene
product from Pseudomonas aureofaciens (Pierson, L. S., et al. 1994.
Phenazine antibiotic biosynthesis in Pseudomonas aureofaciens 30-84
is regulated by PhzR in response to cell density. J. Bacteriol.
176:3966-3974); rhlR gene product from Pseudomonas aeruginosa
(Ochsner, U. A. et al. 1994. Isolation and characterization of a
regulatory gene affecting rhamnolipid biosurfactant synthesis in
Pseudomonas aeruginosa. J. Bacteriol. 176:2044-2054); rsmA gene
product from Erwinia carotovora subsp. carotovora (Cui, Y., et al.
1995. Identification of a global repressor gene, rsmA, of Erwinia
carotovora subsp. carotovora that controls extracellular enzymes,
N-(3-oxohexanoyl)-L-homoserine lactone, and pathogenicity in
soft-rotting Erwinia spp. J. Bacteriol. 177:5108-5115); rsmB gene
product from Erwinia carotovora subsp. carotovora (Cui, Y., et al.
1999. rsmC of the soft-rotting bacterium Erwinia carotovora subsp.
carotovora negatively controls extracellular enzyme and harpin(Ecc)
production and virulence by modulating levels of regulatory RNA
(rsmB) and RNA-binding protein (RsmA). J. Bacteriol.
181:6042-6052); sirA gene product from Salmonella enterica serovar
Typhimurium (Goodier, R. I., and B. M. Ahmer. 2001. SirA orthologs
affects both motility and virulence. J. Bacteriol. 183:2249-2258);
taf gene product from Vibrio cholerae (Salinas, P. C., et al. 1989.
Regulation of the iron uptake system in Vibrio anguillarum:
evidence for a cooperative effect between two transcriptional
activators. Proc. Natl. Acad. Sci. 86:3529-3522); tcpP gene product
from Vibrio cholerae (Hase, C. C., and J. J. Mekalanos. 1998. TcpP
protein is a positive regulator of virulence gene expression in
Vibrio cholerae. Proc. Natl. Acad. Sci. 95:730-734); toxR gene
product from Vibrio cholerae (Miller, V. L., and J. J. Mekalanos.
1984. Synthesis of cholera toxin is positively regulated at the
transcriptional level by toxR. Proc. Natl. Acad. Sci.
81:3471-4375); toxS gene product from Vibrio cholerae (Miller, V.
L., et al. 1989. Identification of toxS, a regulatory gene whose
product enhances toxR-mediated activation of the cholera toxin
promoter. J. Bacteriol. 171:1288-1293); toxT from Vibrio cholerae
(Kaufman, M. R., et al. 1993. Biogenesis and regulation of the
Vibrio cholerae toxin-coregulated pilus: analogies to other
virulence factor secretory systems. Gene. 126:43-49); traM gene
product from Agrobacterium tumefaciens (Faqua, C., et al. 1995.
Activity of the Agrobacterium Ti plasmid conjugal transfer
regulator TraR is inhibited by the product of the traM gene. J.
Bacteriol. 177:1367-1373); traR gene product from Agrobacterium
tumefaciens (Piper, K. R., et al. 1993. Conjugation factor of
Agrobacterium tumefaciens regulates Ti plasmid transfer by
autoinduction. Nature. 362:448-450); vicH gene product from Vibrio
cholerae (Tendeng, C., et al. 2000. Isolation and characterization
of vicH, encoding a new pleiotropic regulator in Vibrio cholerae.
J. Bacteriol. 182:2026-2032); vspR gene product from Vibrio
cholerae (Yildiz, F. H., et al. 2001. VpsR, a Member of the
Response Regulators of the Two-Component Regulatory Systems, Is
Required for Expression of vps Biosynthesis Genes and
EPS(ETr)-Associated Phenotypes in Vibrio cholerae O1 El Tor. J.
Bacteriol. 183:1716-1726).
[0349] II. C.5. b. Bacillus subtilis
[0350] Regulatory elements, promoters and other expression elements
and expression elements from B subtilis include but are not limited
to abrB (Perego, M., et al. 1988. Structure of the gene for the
transition state regulator, abrB: regulator synthesis is controlled
by the spo0A sporulation gene in Bacillus subtilis. Mol. Microbiol.
2:698-699); acoR (Ali, N. O., et al. 2001. Regulation of the
acetoin catabolic pathway is controlled by sigma L in Bacillus
subtilis. J. Bacteriol. 183:2497-2504); ahrC (Klinger, U., et al.
1995. A binding site for activation by the Bacillus subtilis AhrC
protein, a repressor/activator of arginine metabolism. Mol. Gen.
Genet. 248:329-340); alaR (Sohenshein, A. L., J. A. Hoch, and R.
Losick (eds.) 2002. Bacillus subtilis and its closest relatives:
from genes to cells. American Society for Microbiology, Washington
D.C.); alsR (Renna, M. C., et al. 1993. Regulation of the Bacillus
subtilis alsS, alsD, and alsR genes involved in
post-exponential-phase production of acetoin. J. Bacteriol.
175:3863-3875); ansR (Sun, D., and P. Setlow. 1993. Cloning and
nucleotide sequence of the Bacillus subtilis ansR gene, which
encodes a repressor of the ans operon coding for L-asparaginase and
L-aspartase. J. Bacteriol. 175:2501-2506); araR (Sa-Nogueira, I.,
and L. J. Mota. 1997. Negative regulation of L-arabinose metabolism
in Bacillus subtilis: characterization of the araR (araC) gene. J.
Bacteriol. 179:1598-1608); arfM (Marino, M., et al. 2001.
Modulation of anaerobic energy metabolism of Bacillus subtilis by
arfM (ywiD). J. Bacteriol. 183:6815-6821); arsR (Rosenstein, R., et
al. 1992. Expression and regulation of the antimonite, arsenite,
and arsenate resistance operon of Staphylococcus xylosus plasmid
pSX267. J. Bacteriol. 174:3676-3683); azlB (Belitsky, B. R., et al.
1997. An lrp-like gene of Bacillus subtilis involved in
branched-chain amino acid transport. J. Bacteriol. 179:54485457);
birA (Bower, S., et al. 1995. Cloning and characterization of the
Bacillus subtilis birA gene encoding a repressor of the biotin
operon. J. Bacteriol. 177:2572-2575); bkdR (Bebarbouille, M., et
al. 1999. Role of bkdR, a transcriptional activator of the
sigL-dependent isoleucine and valine degradation pathway in
Bacillus subtilis. J. Bacteriol. 181:2059-2066); bltR (Ahmed, M.,
et al. 1995. Two highly similar multidrug transporters of Bacillus
subtilis whose expression is differentially regulated. J.
Bacteriol. 177:3904-3910); bmrR (Ahmed, M., et al. 1994. A protein
that activates expression of a multidrug efflux transporter upon
binding the transporter substrates. J. Biol. Chem.
269:28506-28513); ccpA (Henkin, T. M., et al. 1991. Catabolite
repression of alpha-amylase gene expression in Bacillus subtilis
involves a trans-acting gene product homologous to the Escherichia
coli lac1 and galR repressors. Mol. Microbiol. 5:575-584); ccpB
(Chauvaux, S., et al. 1998. CcpB, a novel transcription factor
implicated in catabolite repression in Bacillus subtilis. J.
Bacteriol. 180:491-497); ccpC (Jourlin-Castelli, C., et al. 2000.
CcpC, a novel regulator of the LysR family required for glucose
repression of the citB gene in Bacillus subtilis. J. Mol. Biol.
295:865-878); cggR (Fillinger, S., et al. 2000. Two
glyceraldehyde-3-phosphate dehydrogenases with opposite
physiological roles in a nonphotosynthetic bacterium. J. Biol.
Chem. 275:14031-14037); cheB (Bischoff, D. S., and G. W. Ordal.
1991. Sequence and characterization of Bacillus subtilis CheB, a
homolog of Escherichia coli CheY, and its role in a different
mechanism of chemotaxis. J. Biol. Chem. 266:12301-12305); cheY
(Bischoff, D. S., et al. 1993. Purification and characterization of
Bacillus subtilis CheY. Biochemistry 32:9256-9261); citR (Jin, S.,
and A. L. Sonenshein. 1994. Transcriptional regulation of Bacillus
subtilis citrate synthase genes. J. Bacteriol. 176:4680-4690); citT
(Yamamoto, H., et al. 2000. The CitST two-component system
regulates the expression of the Mg-citrate transporter in Bacillus
subtilis. Mol. Microbiol. 37:898-912); codY (Slack, F. J., et al.
1995. A gene required for nutritional repression of the Bacillus
subtilis dipeptide permease operon. Mol. Microbiol. 15:689-702);
comA (Nakano, M. M., and P. Zuber. 1989. Cloning and
characterization of srfB, a regulatory gene involved in surfactin
production and competence in Bacillus subtilis. J. Bacteriol.
171:5347-5353); comK (Msadek, T., et al. 1994. MecB of Bacillus
subtilis, a member of the ClpC ATPase family, is a pleiotropic
regulator controlling competence gene expression and growth at high
temperature. Proc. Natl. Acad. Sci. 91:5788-5792); comQ (Weinrauch,
Y., et al. 1991. Sequence and properties of comQ, a new competence
regulatory gene of Bacillus subtilis. J. Bacteriol. 173:5685-5693);
cssR (Hyyrylainen, H. L., et al. 2001. A novel two-component
regulatory system in Bacillus subtilis for the survival of severe
secretion stress. Mol. Microbiol. 41:1159-1172); ctsR (Kruger, E.,
and M. Hecker. 1998. The first gene of the Bacillus subtilis clpC
operon, ctsR, encodes a negative regulator of its own operon and
other class III heat shock genes. J. Bacteriol. 180:6681-6688);
dctR (Sohenshein, A. L., J. A. Hoch, and R. Losick (eds.) 2002.
Bacillus subtilis and its closest relatives: from genes to cells.
American Society for Microbiology, Washington D.C.); degA (Bussey,
L. B., and R. L. Switzer. 1993. The degA gene product accelerates
degradation of Bacillus subtilis phosphoribosylpyrophosphate
amidotransferase in Escherichia coli. J. Bacteriol. 175:6348-6353);
degU (Msadek, T., et al. 1990. Signal transduction pathway
controlling synthesis of a class of degradative enzymes in Bacillus
subtilis: expression of the regulatory genes and analysis of
mutations in degS and degU. J. Bacteriol. 172:824-834); deoR
(Saxild, H. H., et al. 1996. Dra-nupC-pdp operon of Bacillus
subtilis: nucleotide sequence, induction by deoxyribonucleosides,
and transcriptional regulation by the deoR-encoded DeoR repressor
protein. J. Bacteriol. 178:424-434); exuR (Sohenshein, A. L., J. A.
Hoch, and R. Losick (eds.) 2002. Bacillus subtilis and its closest
relatives: from genes to cells. American Society for Microbiology,
Washington D.C.); frn (Cruz Ramos, H., et al., 1995. Anaerobic
transcription activation in Bacillus subtilis: identification of
distinct FNR-dependent and -independent regulatory mechanisms. EMBO
J. 14:5984-5994); fruR (Saier, M. H. Jr. 1996. Cyclic
AMP-independent catabolite repression in bacteria. FEMS Microbiol.
Lett. 138:97-103); fur (Chen, L., et al. 1993. Metalloregulation in
Bacillus subtilis: isolation and characterization of two genes
differentially repressed by metal ions. J. Bacteriol.
175:5428-5437); gabR (Sohenshein, A. L., J. A. Hoch, and R. Losick
(eds.) 2002. Bacillus subtilis and its closest relatives: from
genes to cells. American Society for Microbiology, Washington
D.C.); gerE (Holand, S. K., et al. 1987. The possible DNA-binding
nature of the regulatory proteins, encoded by spoIID and gerE,
involved in the sporulation of Bacillus subtilis. J. Gen.
Microbiol. 133:2381-2391); glcR (Stulke, J., et al. 2001.
Characterization of glucose-repression-resistan- t mutants of
Bacillus subtilis: identification of the glcR gene. Arch.
Microbiol. 175:441-449); glcT (Paulsen, I. T., et al. 1998.
Characterization of glucose-specific catabolite
repression-resistant mutants of Bacillus subtilis: identification
of a novel hexose:H+ symporter. J. Bacteriol. 180:498-504); glnR
(Schreier, H. J., et al. 1989. Regulation of Bacillus subtilis
glutamine synthetase gene expression by the product of the glnR
gene. J. Mol. Biol. 210:51-63); glpP (Holmberg, C., and B. Rutberg.
1991. Expression of the gene encoding glycerol-3-phosphate
dehydrogenase (glpD) in Bacillus subtilis is controlled by
antitermination. Mol. Microbiol. 5:2891-2900); gltC (Bohannon, D.
E. and A. L. Sonenshein. 1989. Positive regulation of glutamate
biosynthesis in Bacillus subtilis. J. Bacteriol. 171:4718-4727);
gltR (Belitsky, B. R., and A. L. Sonenshein. 1997. Altered
transcription activation specificity of a mutant form of Bacillus
subtilis GltR, a LysR family member. J. Bacteriol. 179:1035-1043);
gntR (Fujita, Y., and T. Fujita. 1987. The gluconate operon gnt of
Bacillus subtilis encodes its own transcriptional negative
regulator. Proc. Natl. Acad. Sci. 84:4524-4528); gutR (Ye, R., et
al. 1994. Glucitol induction in Bacillus subtilis is mediated by a
regulatory factor, GutR. J. Bacteriol. 176:3321-3327); hpr (Perego,
M., and J. A. Hoch. 1988. Sequence analysis and regulation of the
hpr locus, a regulatory gene for protease production and
sporulation in Bacillus subtilis. J. Bacteriol. 170:2560-2567);
hrcA (Schulz, A., and W. Schumann. 1996. hrcA, the first gene of
the Bacillus subtilis dnaK operon encodes a negative regulator of
class I heat shock genes. J. Bacteriol. 178:1088-1093); hutP (Oda,
M., et al. 1992. Analysis of the transcriptional activity of the
hut promoter in Bacillus subtilis and identification of a
cis-acting regulatory region associated with catabolite repression
downstream from the site of transcription. Mol. Microbiol.
6:2573-2582); hxlR (Sohenshein, A. L., J. A. Hoch, and R. Losick
(eds.) 2002. Bacillus subtilis and its closest relatives: from
genes to cells. American Society for Microbiology, Washington
D.C.); iolR (Yoshida, K. I., et al. 1999. Interaction of a
repressor and its binding sites for regulation of the Bacillus
subtilis iol divergon. J. Mol. Biol. 285:917-929); kdgR (Pujic, P.,
et al. 1998. The kdgRKAT operon of Bacillus subtilis: detection of
the transcript and regulation by the kdgR and ccpA genes.
Microbiology. 144:3111-3118); kipR (Sohenshein, A. L., J. A. Hoch,
and R. Losick (eds.) 2002. Bacillus subtilis and its closest
relatives: from genes to cells. American Society for Microbiology,
Washington D.C.); lacR (Errington, J., and C. H. Vogt. 1990.
Isolation and characterization of mutations in the gene encoding an
endogenous Bacillus subtilis beta-galactosidase and its regulator.
J. Bacteriol. 172:488-490); levR (Bebarbouille, M., et al. 1991.
The transcriptional regulator LevR of Bacillus subtilis has domains
homologous to both sigma 54- and phosphotransferase
system-dependent regulators. Proc. natl. Acad. Sci. 88:2212-2216);
lexA (Lovett, C. M. Jr., and J. W. Roberts. 1985. Purification of a
RecA protein analogue from Bacillus subtilis. J. Biol. Chem.
260:3305-3313); licR (Tobisch, S., et a. 1997. Identification and
characterization of a new beta-glucoside utilization system in
Bacillus subtilis. J. Bacteriol. 179:496-506); licT (Le Coq, D., et
al. 1995. New beta-glucoside (bgl) genes in Bacillus subtilis: the
bglP gene product has both transport and regulatory functions
similar to those of BglF, its Escherichia coli homolog. J.
Bacteriol. 177:1527-1535); lmrA (Kumano, M., et al. 1997. A 32 kb
nucleotide sequence from the region of the lincomycin-resistance
gene (22 degrees-25 degrees) of the Bacillus subtilis chromosome
and identification of the site of the lin-2 mutation. Microbiology.
143:2775-2782); lrpA gene product from Pyrococcus furiosus
(Brinkman, A. B., et al. 2000. An Lrp-like transcriptional
regulator from the archaeon Pyrococcus furiosus is negatively
autoregulated. J. Biol. Chem. 275:38160-38169); lrpB(Sohenshein, A.
L., J. A. Hoch, and R. Losick (eds.) 2002. Bacillus subtilis and
its closest relatives: from genes to cells. American Society for
Microbiology, Washington D.C.); lrpC (Beloin, C., et al. 1997.
Characterization of an lrp-like (lrpC) gene from Bacillus subtilis.
Mol. Gen. Genet. 256:63-71); lytR (Huang, X., and J. D. Helmann.
1998. Identification of target promoters for the Bacillus subtilis
sigma X factor using a consensus-directed search. J. Mol. Biol.
279:165-173); lytT (Sohenshein, A. L., J. A. Hoch, and R. Losick
(eds.) 2002. Bacillus subtilis and its closest relatives: from
genes to cells. American Society for Microbiology, Washington
D.C.); manR gene product from Listeria monocytogenes (Dalet, K., et
al. 2001. A sigma(54)-dependent PTS permease of the mannose family
is responsible for sensitivity of Listeria monocytogenes to
mesentericin Y105. Microbiology. 147:3263-3269); mntR (Que, Q., and
J. D. Helmann. 2000. Manganese homeostasis in Bacillus subtilis is
regulated by MntR, a bifunctional regulator related to the
diphtheria toxin repressor family of proteins. Mol. Microbiol.
35:1454-1468); msmR gene product from Streptococcus mutans
(Russell, R. R., et al. 1992. A binding protein-dependent transport
system in Streptococcus mutans responsible for multiple sugar
metabolism. J. Biol. Chem. 267:4631-4637); mta (Baranova, N. N., et
al. 1999. Mta, a global MerR-type regulator of the Bacillus
subtilis multidrug-efflux transporters. Mol. Microbiol.
31:1549-1559); mtlR (Henstra, S. A., et al. 1999. The Bacillus
stearothermophilus mannitol regulator, MtlR, of the
phosphotransferase system. A DNA-binding protein, regulated by HPr
and iicbmtl-dependent phosphorylation. J. Biol. Chem.
274:4754-4763); mtrB (Gollnick, P., et al. 1990. The mtr locus is a
two-gene operon required for transcription attenuation in the trp
operon of Bacillus subtilis. Proc. Natl. Acad. Sci. 87:8726-8730);
nhaX (Sohenshein, A. L., J. A. Hoch, and R. Losick (eds.) 2002.
Bacillus subtilis and its closest relatives: from genes to cells.
American Society for Microbiology, Washington D.C.); toxR gene
product from Vibrio cholerae (Miller, V. L., and J. J. Mekalanos.
1984. Synthesis of cholera toxin is positively regulated at the
transcriptional level by toxR. Proc. Natl. Acad. Sci.
81:3471-3475); padR gene product from Pediococcus pentosaceus
(Barthelmebs, L., et al. 2000. Inducible metabolism of phenolic
acids in Pediococcus pentosaceus is encoded by an autoregulated
operon which involves a new class of negative transcriptional
regulator. J. Bacteriol. 182:6724-6731); paiA (Sohenshein, A. L.,
J. A. Hoch, and R. Losick (eds.) 2002. Bacillus subtilis and its
closest relatives: from genes to cells. American Society for
Microbiology, Washington D.C.); paiB (Id.); perA (Id.); phoP
(Birkey, S. M., et al. 1994. A pho regulon promoter induced under
sporulation conditions. Gene. 147:95-100); pksA (Sohenshein, A. L.,
J. A. Hoch, and R. Losick (eds.) 2002. Bacillus subtilis and its
closest relatives: from genes to cells. American Society for
Microbiology, Washington D.C.); pucR (Schultz, A. C., et al. 2001.
Functional analysis of 14 genes that constitute the purine
catabolic pathway in Bacillus subtilis and evidence for a novel
regulon controlled by the PucR transcription activator. J.
Bacteriol. 183:3293-3302); purR (Weng, M., et al. 1995.
Identification of the Bacillus subtilis pur operon repressor. Proc.
Natl. Acad. Sci. 92:7455-7459); pyrR (Martinussen, J., et al. 1995.
Two genes encoding uracil phosphoribosyltransferase are present in
Bacillus subtilis. J. Bacteriol. 177:271-274); rbsR (Rodionov, D.
A., et al. 2001. Transcriptional regulation of pentose utilisation
systems in the Bacillus/Clostridium group of bacteria. FEMS
Microbiol. Lett. 205:305-314); resD (Suin, G., et al. 1996.
Regulators of aerobic and anaerobic respiration in Bacillus
subtilis. J. Bacteriol. 178:1374-1385); rocR (Gardan, R., et al.
1997. Role of the transcriptional activator RocR in the
arginine-degradation pathway of Bacillus subtilis. Mol. Microbiol.
24:825-837); rsiX (Tortosa, P., et al. 2000. Characterization of
ylbF, a new gene involved in competence development and sporulation
in Bacillus subtilis. Mol. Microbiol. 35:1110-1119); sacT
(Debarbouille, M., et al. 1990. The sacT gene regulating the sacPA
operon in Bacillus subtilis shares strong homology with
transcriptional antiterminators. J. Bacteriol. 172:3966-3973);
sacV(Wong, S. L., et al. 1988. Cloning and nucleotide sequence of
senN, a novel `Bacillus natto` (B. substilis) gene that regulates
expression of extracellular protein genes. J. Gen. Microbiol.
134:3269-3276); sacY (Steinmetz, M., et al 1989. Induction of
saccharolytic enzymes by sucrose in Bacillus subtilis: evidence for
two partially interchangeable regulatory pathways. J. Bacteriol.
171:1519-1523); senS (Wang, L. F., and R. H. Dori. 1990. Complex
character of senS, a novel gene regulating expression of
extracellular-protein genes of Bacillus subtilis. J. Bacteriol.
172:1939-1947); sinR (Bai, U., et al. 1993. SinI modulates the
activity of SinR, a developmental switch protein of Bacillus
subtilis, by protein-protein interaction. Genes Dev. 7:139-148);
slr (Asayama, M., et al. 1998. Translational attenuation of the
Bacillus subtilis spo0B cistron by an RNA structure encompassing
the initiation region. Nucleic Acids Res. 26:824-830); splA
(Fajardo-Cavazos, P., and W. L. Nicholson. 2000. The TRAP-like SplA
protein is a trans-acting negative regulator of spore photoproduct
lyase synthesis during Bacillus subtilis sporulation. J. Bacteriol.
182:555-560); spo0A (Smith, I., et al. 1991. The role of negative
control in sporulation. Res. Microbiol. 142:831-839); spo0F
(Lewandoski, M., et al. 1986. Transcriptional regulation of the
spo0F gene of Bacillus subtilis. J. Bacteriol. 168:870-877);
spoIIID (Kunkel, B., et al. 1989. Temporal and spatial control of
the mother-cell regulatory gene spoIIID of Bacillus subtilis.
Genes. Dev. 3:1735-1744); spoVT (Bagyan, I, et al. 1996. A
compartmentalized regulator of developmental gene expression in
Bacillus subtilis. J. Bacteriol.
178:4500-4507); tenA (Pang, A. S., et al. 1991. Cloning and
characterization of a pair of novel genes that regulate production
of extracellular enzymes in Bacillus subtilis. J. Bacteriol.
173:46-54); tenl (Sohenshein, A. L., J. A. Hoch, and R. Losick
(eds.) 2002. Bacillus subtilis and its closest relatives: from
genes to cells. American Society for Microbiology, Washington
D.C.); tnrA (Wray, L. V., Jr., et al. 1996. TnrA, a transcription
factor required for global nitrogen regulation in Bacillus
subtilis. Proc. Natl. Acad. Sci. 93:8841-8845); treR (Schock, F.,
and M. K. Dahl. 1996. Expression of the tre operon of Bacillus
subtilis 168 is regulated by the repressor TreR. J. Bacteriol.
178:4576-4581); xre (McDonnell, G. E., et al. 1994. Genetic control
of bacterial suicide: regulation of the induction of PBSX in
Bacillus subtilis. J. Bacteriol. 176:5820-5830); xylR gene product
from Bacillus megaterium (Rygus, T., et al. 1991. Molecular
cloning, structure, promoters and regulatory elements for
transcription of the Bacillus megaterium encoded regulon for xylose
utilization. Arch. Microbiol. 155:535:542); yacF (Sohenshein, A.
L., J. A. Hoch, and R. Losick (eds.) 2002. Bacillus subtilis and
its closest relatives: from genes to cells. American Society for
Microbiology, Washington D.C.); and zur (Gaballa, A., and J. D.
Helmann. 1998. Identification of a zinc-specific metalloregulatory
protein, Zur, controlling zinc transport operons in Bacillus
subtilis. J. Bacteriol. 180:5815-5821).
[0351] II.C.5.c. Other Eubacteria
[0352] Regulatory elements, promoters and other expression elements
and factors from prokaryotes other than E. coli and B. substilis
include without limitation ahyRI gene product from Aeromonas
hydrophila and Aeromonas salmomicida (Swift, S., et al. 1997.
Quorum sensing in Aeromonas hydrophila and Aeromonas salmomicida:
identification of the LuxRI homologs AhyRI and AsaRI and their
cognate N-acylhomoserine lactone signal molecules. J. Bacteriol.
179:5271-5281); angR gene product from Vibrio anguillarum (Salinas,
P. C., et al. 1989. Regulation of the iron uptake system in Vibrio
anguillarum: evidence for a cooperative effect between two
transcriptional activators. Proc. Natl. Acad. Sci. 86:3529-3522);
aphA gene product from Vibrio cholerae (Kovacikova, G., and K.
Skorupski. 2001. Overlapping binding sites for the virulence gene
regulators AphA, AphB and cAMP-CRP at the Vibrio cholerae tcpPH
promoter. Mol. Microbiol. 41:393-407); aphB gene product from
Vibrio cholerae (Kovachikova, G., and K. Skorupski. 2000.
Differential activation of the tcpPH promoter by AphB determines
biotype specificity of virulence gene expression in Vibrio
cholerae. J. Bacteriol. 182:3228-3238); comE gene product from
Streptococcus pneumoniae (Ween, O., et al. 1999. Identification of
DNA binding sites for ComE, a key regulator of natural competence
in Streptococcus pneumoniae. Mol. Microbiol. 33:817-827); esaI gene
product from Pantoea stewartii subsp. stewartii (von Bodman, S. B.,
et al. 1998. A negative regulator mediates quorum-sensing control
of exopolysaccharide production in Pantoea stewartii subsp.
stewartii. Proc. Natl. Acad. Sci. 95:7687-7692); esaR gene product
from Pantoea stewartii subsp. stewartii (Id.); expI gene product
from Erwinia chrysanthemi (Nasser, W., et al. 1998.
Characterization of the Erwinia chrysanthemi expI-expR locus
directing the synthesis of two N-acyl-homoserine lactone signal
molecules. Mol. Microbiol. 29:1391-1405); expR gene product from
Erwinia chrysanthemi (Id.); gacA gene product from Pseudomonas
aeruginosa (Pessi, G., and D. Haas. 2001. Dual control of hydrogen
cyanide biosynthesis by the global activator GacA in Pseudomonas
aeruginosa PAO1. FEMS Microbiol. Lett. 200:73-78); hapR gene
product from Vibrio cholerae (Jobling, M. G., and R. K. Holmes.
Characterization of hapR, a positive regulator of the Vibrio
cholerae HA/protease gene hap, and its identification as a
functional homologue of the Vibrio harveyi luxR gene. Mol.
Microbiol. 26:1023-1034); hlyR gene product from Vibrio cholerae
(von Mechow, S., et al. 1985. Mapping of a gene that regulates
hemolysin production in Vibrio cholerae. J. Bacteriol.
163:799-802); hupR gene product from Vibrio vulnificus (Litwin, C.
M., and J. Quackenbush. 2001. Characterization of a Vibrio
vulnificus LysR homologue, HupR, which regulates expression of the
haem uptake outer membrane protein, HupA. Microb. Pathog.
31:295-307); lasR gene product from Pseudomonas aerugenosa
(Gambella, M. J., and B. H. Igleweski. 1991. Cloning and
characterization of the Pseudomonas aeruginosa lasR gene, a
transcriptional activator of elastase expression. J. Bacteriol.
173:3000-3009); leuO gene product from Salmonella enterica serovar
Typhimurium (Fang, M., and H. Y. Wu. 1998. A promoter relay
mechanism for sequential gene activation. J. Bacteriol.
180:626-633); luxI gene product from Vibrio cholerae (Engebrecht,
J., and M. Silverman. Nucleotide sequence of the regulatory locus
controlling expression of bacterial genes for bioluminescence.
Nucleic Acids Res. 15:10455-10467); luxO gene product from Vibrio
cholerae (Bassler, B. L., et al. 1994. Sequence and function of
LuxO, a negative regulator of luminescence in Vibrio harveyi. Mol.
Microbiol. 12:403-412); luxR gene product from Vibrio cholerae
(Engebrecht, J., and M. Silverman. Nucleotide sequence of the
regulatory locus controlling expression of bacterial genes for
bioluminescence. Nucleic Acids Res. 15:10455-10467); phzR gene
product from Pseudomonas aureofaciens (Pierson, L. S., et al. 1994.
Phenazine antibiotic biosynthesis in Pseudomonas aureofaciens 30-84
is regulated by PhzR in response to cell density. J. Bacteriol.
176:3966-3974); rhlR gene product from Pseudomonas aeruginosa
(Ochsner, U. A. et al. 1994. Isolation and characterization of a
regulatory gene affecting rhamnolipid biosurfactant synthesis in
Pseudomonas aeruginosa. J. Bacteriol. 176:2044-2054); rsmA gene
product from Erwinia carotovora subsp. carotovora (Cui, Y., et al.
1995. Identification of a global repressor gene, rsmA, of Erwinia
carotovora subsp. carotovora that controls extracellular enzymes,
N-(3-oxohexanoyl)-L-homoserine lactone, and pathogenicity in
soft-rotting Erwinia spp. J. Bacteriol. 177:5108-5115); rsmB gene
product from Erwinia carotovora subsp. carotovora (Cui, Y., et al.
1999. rsmC of the soft-rotting bacterium Erwinia carotovora subsp.
carotovora negatively controls extracellular enzyme and harpin(Ecc)
production and virulence by modulating levels of regulatory RNA
(rsmB) and RNA-binding protein (RsmA). J. Bacteriol.
181:6042-6052); sirA gene product from Salmonella enterica serovar
Typhimurium (Goodier, R. I., and B. M. Ahmer. 2001. SirA orthologs
affects both motility and virulence. J. Bacteriol. 183:2249-2258);
taf gene product from Vibrio cholerae (Salinas, P. C., et al. 1989.
Regulation of the iron uptake system in Vibrio anguillarum:
evidence for a cooperative effect between two transcriptional
activators. Proc. Natl. Acad. Sci. 86:3529-3522); tcpP gene product
from Vibrio cholerae (Hase, C. C., and J. J. Mekalanos. 1998. TcpP
protein is a positive regulator of virulence gene expression in
Vibrio cholerae. Proc. Natl. Acad. Sci. 95:730-734); toxR gene
product from Vibrio cholerae (Miller, V. L., and J. J. Mekalanos.
1984. Synthesis of cholera toxin is positively regulated at the
transcriptional level by toxR. Proc. Natl. Acad. Sci.
81:3471-4375); toxS gene product from Vibrio cholerae (Miller, V.
L., et al. 1989. Identification of toxS, a regulatory gene whose
product enhances toxR-mediated activation of the cholera toxin
promoter. J. Bacteriol. 171:1288-1293); toxT from Vibrio cholerae
(Kaufman, M. R., et al. 1993. Biogenesis and regulation of the
Vibrio cholerae toxin-coregulated pilus: analogies to other
virulence factor secretory systems. Gene. 126:43-49); traM gene
product from Agrobacterium tumefaciens (Faqua, C., et al. 1995.
Activity of the Agrobacterium Ti plasmid conjugal transfer
regulator TraR is inhibited by the product of the traM gene. J.
Bacteriol. 177:1367-1373); traR gene product from Agrobacterium
tumefaciens (Piper, K. R., et al. 1993. Conjugation factor of
Agrobacterium tumefaciens regulates Ti plasmid transfer by
autoinduction. Nature. 362:448-450); vicH gene product from Vibrio
cholerae (Tendeng, C., et al. 2000. Isolation and characterization
of vicH, encoding a new pleiotropic regulator in Vibrio cholerae.
J. Bacteriol. 182:2026-2032); vspR gene product from Vibrio
cholerae (Yildiz, F. H., et al. 2001. VpsR, a Member of the
Response Regulators of the Two-Component Regulatory Systems, Is
Required for Expression of vps Biosynthesis Genes and
EPS(ETr)-Associated Phenotypes in Vibrio cholerae O1 El Tor. J.
Bacteriol. 183:1716-1726); gadR gene product from Lactococcus
lactis (Sanders, J. W., et al. 1997. A chloride-inducible gene
expression cassette and its use in induced lysis of Lactococcus
lactis. Appl. Environ. Microbiol. 63:4877-4882); hrpB gene product
from Pseudomonas solanacearum (Van Gijsegem, F., et al. 1995. The
hrp gene locus of Pseudomonas solanacearum, which controls the
production of a type III secretion system, encodes eight proteins
related to components of the bacterial flagellar biogenesis
complex. Mol. Microbiol. 15:1095-1114); carotovora subsp.
carotovora (Cui, Y., et al. 1995. Identification of a global
repressor gene, rsmA, of Erwinia carotovora subsp. carotovora that
controls extracellular enzymes, N-(3-oxohexanoyl)-L-homoserine
lactone, and pathogenicity in soft-rotting Erwinia spp. J.
Bacteriol. 177:5108-5115); rsmB gene product from Erwinia
carotovora subsp. carotovora (Cui, Y., et al. 1999. rsmC of the
soft-rotting bacterium Erwinia carotovora subsp. carotovora
negatively controls extracellular enzyme and harpin(Ecc) production
and virulence by modulating levels of regulatory RNA (rsmB) and
RNA-binding protein (RsmA). J. Bacteriol. 181:6042-6052); sirA gene
product from Salmonella enterica serovar Typhimurium (Goodier, R.
I., and B. M. Ahmer. 2001. SirA orthologs affects both motility and
virulence. J. Bacteriol. 183:2249-2258); taf gene product from
Vibrio cholerae (Salinas, P. C., et al. 1989. Regulation of the
iron uptake system in Vibrio anguillarum: evidence for a
cooperative effect between two transcriptional activators. Proc.
Natl. Acad. Sci. 86:3529-3522); tcpP gene product from Vibrio
cholerae (Hase, C. C., and J. J. Mekalanos. 1998. TcpP protein is a
positive regulator of virulence gene expression in Vibrio cholerae.
Proc. Natl. Acad. Sci. 95:730-734); toxR gene product from Vibrio
cholerae (Miller, V. L., and J. J. Mekalanos. 1984. Synthesis of
cholera toxin is positively regulated at the transcriptional level
by toxR. Proc. Natl. Acad. Sci. 81:3471-4375); toxS gene product
from Vibrio cholerae (Miller, V. L., et al. 1989. Identification of
toxS, a regulatory gene whose product enhances toxR-mediated
activation of the cholera toxin promoter. J. Bacteriol.
171:1288-1293); toxT from Vibrio cholerae (Kaufman, M. R., et al.
1993. Biogenesis and regulation of the Vibrio cholerae
toxin-coregulated pilus: analogies to other virulence factor
secretory systems. Gene. 126:43-49); traM gene product from
Agrobacterium tumefaciens (Faqua, C., et al. 1995. Activity of the
Agrobacterium Ti plasmid conjugal transfer regulator TraR is
inhibited by the product of the traM gene. J. Bacteriol.
177:1367-1373); traR gene product from Agrobacterium tumefaciens
(Piper, K. R., et al. 1993. Conjugation factor of Agrobacterium
tumefaciens regulates Ti plasmid transfer by autoinduction. Nature.
362:448-450); vicH gene product from Vibrio cholerae (Tendeng, C.,
et al. 2000. Isolation and characterization of vicH, encoding a new
pleiotropic regulator in Vibrio cholerae. J. Bacteriol.
182:2026-2032); vspR gene product from Vibrio cholerae (Yildiz, F.
H., et al. 2001. VpsR, a Member of the Response Regulators of the
Two-Component Regulatory Systems, Is Required for Expression of vps
Biosynthesis Genes and EPS(ETr)-Associated Phenotypes in Vibrio
cholerae O1 El Tor. J. Bacteriol. 183:1716-1726); lrpA gene product
from Pyrococcus furiosus (Brinkman, A. B., et al. 2000. An Lrp-like
transcriptional regulator from the archaeon Pyrococcus furiosus is
negatively autoregulated. J. Biol. Chem. 275:38160-38169); manR
gene product from Listeria monocytogenes (Dalet, K., et al. 2001. A
sigma(54)-dependent PTS permease of the mannose family is
responsible for sensitivity of Listeria monocytogenes to
mesentericin Y105. Microbiology. 147:3263-3269); msmR gene product
from Streptococcus mutans (Russell, R. R., et al. 1992. A binding
protein-dependent transport system in Streptococcus mutans
responsible for multiple sugar metabolism. toxR gene product from
Vibrio cholerae (Miller, V. L., and J. J. Mekalanos. 1984.
Synthesis of cholera toxin is positively regulated at the
transcriptional level by toxR. Proc. Natl. Acad. Sci.
81:3471-3475); padR gene product from Pediococcus pentosaceus
(Barthelmebs, L., et al. 2000. Inducible metabolism of phenolic
acids in Pediococcus pentosaceus is encoded by an autoregulated
operon which involves a new class of negative transcriptional
regulator. J. Bacteriol. 182:6724-6731); purR (Weng, M., et al.
1995); and xylR gene product from Bacillus megaterium (Rygus, T.,
et al. 1991. Molecular cloning, structure, promoters and regulatory
elements for transcription of the Bacillus megaterium encoded
regulon for xylose utilization. Arch. Microbiol. 155:535:542).
[0353] II.C.5.d. Bacteriophage and Transposable Elements
[0354] Regulatory elements, promoters and other expression elements
from bacteriophage and transposable elements include without
limitation cI gene product from bacteriophage lambda mation and/or
segregated minicells (Reichardt, L. F. 1975. Control of
bacteriophage lambda repressor synthesis: regulation of the
maintenance pathway of the cro and cI products. J. Mol. Biol.
93:289-309); (Love, C. A., et al. 1996. Stable high-copy-number
bacteriophage lambda promoter vectors for overproduction of
proteins in Escherichia coli. Gene. 176:49-53); the c2 gene product
from bacteriophage P22 (Gough, M., and S. Tokuno. 1975. Further
structural and functional analogies between the repressor regions
of phages P22 and lambda. Mol. Gen. Genet. 138:71-79); the cro gene
from bacteriophage lambda (Reichardt, L. F. 1975. Control of
bacteriophage lambda repressor synthesis: regulation of the
maintenance pathway of the cro and cI products. J. Mol. Biol.
93:289-309); the ant gene from bacteriophage P22 (Youderian, P. et
al. 1982. Sequence determinants of promotor activity. Cell.
30:843-853); the mnt gene from bacteriophage P22 (Gough, M. 1970.
Requirement for a functional int product in temperature inductions
of prophage P22 ts mnt. J. Virol. 6:320-325; Prell, H. H. 1978.
Ant-mediated transactivation of early genes in Salmonella prophage
P22 by superinfecting virulent P22 mutants. Mol. Gen. Genet.
164:331-334); the tetR gene product from the TetR family of
bacterial regulators or homologues of this gene or gene product
found in Tn10 and other members of the bacteriophage, animal virus,
Eubacteria, Eucarya or Archaea may be employed to increase the
efficiency of gene expression and protein production in parent
cells prior to minicell formation and/or segregated minicells
(Moyed, H. S., and K. P. Bertrand. 1983. Mutations in multicopy
Tn10 tet plasmids that confer resistance to inhibitory effects of
inducers of tet gene expression. J. Bacteriol. 155:557-564); the
mnt gene product from bacteriophage SP6 mation and/or segregated
minicells (Mead, D. A., et al. 1985. Single stranded DNA SP6
promoter plasmids for engineering mutant RNAs and proteins:
synthesis of a `stretched` preproparathyroid hormone. Nucleic Acids
Res. 13:1103-1118); and the mnt gene product from bacteriophage T7
mation and/or segregated minicells (Steen, R., et al. 1986. T7 RNA
polymerase directed expression of the Escherichia coli rrnB operon.
EMBO J. 5:1099-1103).
[0355] II.C.5.e. Use of Site-Specific Recombination in Expression
Systems
[0356] Included in the design of the invention are techniques that
increase the efficiency of gene expression and protein production
in minicells. By way of non-limiting example, these techniques may
include modification of endogenous and/or exogenous regulatory
elements responsible for activation and/or repression of proteins
to be expressed from chromosomal and/or plasmid expression vectors.
By way of non-limiting example, this system may be applied to any
of the above regulatory elements/systems. Specifically, each of the
above mentioned regulatory systems may be constructed such that the
promotor regions are oriented in a direction away from the gene to
be expressed, or each of the above mentioned gene(s) to be
expressed may be constructed such that the gene(s) to be expressed
is oriented in a direction away from the regulatory region
promotor. Constructed in this system is a methodology dependent
upon site-specific genetic recombination for inversion and
induction of the gene of interest (Backman, K., et al. 1984. Use of
synchronous site-specific recombination in vivo to regulate gene
expression. Bio/Technology 2:1045-1049; Balakrishnan, R., et al.
1994. A gene cassette for adapting Escherichia coli strains as
hosts for att-Int-mediated rearrangement and pL expression vectors.
Gene 138:101-104; Hasan, N., and W. Szybalaki. 1987. Control of
cloned gene expression by promoter inversion in vivo: construction
of improved vectors with a multiple cloning site and the Ptac
promotor. Gene 56:145-151; Wulfing, C., and A. Pluckthun. 1993. A
versatile and highly repressible Escherichia coli expression system
based on invertible promoters: expression of a gene encoding a
toxic gene product. Gene 136:199-203). These invertible promoters
and/or gene regions will allow tight regulation of potentially
toxic protein products. By way of non-limiting example, these
systems may be derived from bacteriophage lambda, bacteriophage Mu,
and/or bacteriophage P22. In any of these potential systems,
regulation of the recombinase may be regulated by any of the
regulatory systems discussed in section II.C.5 and elsewhere
herein.
[0357] II.C.5.e. Use of Copy Number Control Switches
[0358] A method that can be used to increase the efficiency of gene
expression and protein production in minicells involves the
modification of endogenous and/or introduction of exogenous genetic
expression systems such that the number of copies of a gene
encoding a protein to be expressed can be modulated. Copy number
control systems comprise elements designed to modulate copy number
in a controlled fashion.
[0359] In an exemplary mode, copy number is controlled to decrease
the effects of "leaky" (uninduced) expression of toxic gene
products. This allows one to maintain the integrity of a
potentially toxic gene product during processes such as cloning,
culture maintenance, and periods of growth prior to
minicell-induction. That is, decreasing the copy number of a gene
is expected to decrease the opportunity for mutations affecting
protein expression and/or function to arise. Immediately prior to,
during and/or after minicell formation, the copy number may be
increased to optimize the gene dosage in minicells as desired.
[0360] The replication of eubacterial plasmids is regulated by a
number of factors, some of which are contained within the plasmid,
others of which are located on the chromosome. For reviews, see del
Solar, G., et al. 2000. Plasmid copy number control: an
ever-growing story. Mol Microbiol. 37:492-500; del Solar, G., et
al. 1998. Replication and control of circular bacterial plasmids.
Microbiol Mol Biol Rev. 62:434-64; and Filutowicz, M., et al. 1987.
DNA and protein interactions in the regulation of plasmid
replication. J Cell Sci Suppl. 7:15-31.
[0361] By way of non-limiting example, the pcnB gene product, the
wildtype form of which promotes increased ColE1 plasmid copy number
(Soderbom, F., et al. 1997. Regulation of plasmid R1 replication:
PcnB and RNase E expedite the decay of the antisense RNA, CopA.
Mol. Microbiol. 26:493-504), is modulated; and/or mutant forms of
the pcnB gene are introduced into a cell. In an exemplary cell type
that may be used in the methods of the invention, the wildtype pcnB
chromosomal gene is replaced with a mutant pcnB80 allele (Lopilato,
J., et al. 1986. Mutations in a new chromosomal gene of Escherichia
coli K-12, pcnB, reduce plasmid copy number of pBR322 and its
derivatives. Mol. Gen. Genet. 205:285-290). In such cells the copy
number of a ColE1-derived plasmid is decreased. The cell may
further comprise an expression element comprising an inducible
promoter operably linked to an ORF encoding the wild-type pcnB.
Because the wild-type pcnB gene is dominant to the mutant pcnB80
gene, and because the wild-type pcnB gene product promotes
increased ColE1 plasmid copy number, induction of a wild-type pcnB
in the pcnB80 background will increase the plasmid copy number of
ColE1-derived plasmids. Such copy number control systems may be
expressed from the chromosome and/or plasmid to maintain either low
or high plasmid copy number in the absence of induction. Other
non-limiting examples of gene and/or gene products that may be
employed in copy number control systems for ColE1-based replicons
include genes or homologs of genes encoding RNA I, RNA II, rop,
RNAse H, enzymes involved in the process of polyadenylation, RNAse
E, DNA polymerase I, and DNA polymerase III.
[0362] In the case of IncFII-derived replicons, non-limiting
examples of gene and/or gene products that may be employed in copy
number control systems to control plasmid copy include genes or
homologs of the copA, copB, repA, and repB genes. Copy number
control systems may additionally or alternatively include
manipulation of repC, trfA, dnaA, dnaB, dnaC, seqA, genes protein
Pi, genes encoding HU protein subunits (hupA, hupB) and genes
encoding IHF subunits.
[0363] Other elements may also be included to optimize these
plasmid copy number control systems. Such additional elements may
include the addition or deletion of iteron nucleic acid sequences
(Chattoraj, D. K. 2000. Control of plasmid DNA replication by
iterons: no longer paradoxical. Mol. Microbiol. 37:467-476), and
modification of chaperone proteins involved in plasmid replication
(Konieczny, I., et al. 1997. The replication initiation protein of
the broad-host-range plasmid RK2 is activated by the C1pX
chaperone. Proc Natl Acad Sci USA 94:14378-14382).
[0364] II.C.6. Transportation of Inducible and Inhibitory
Compounds
[0365] Included in the design of the invention are techniques that
increase the efficiency of gene expression and protein production
in minicells. By way of non-limiting example, these techniques may
include utilization and/or modification of factors and systems that
modulate the transport of compounds, including but not limited to
inducers and/or inhibitors of expression elements that control
expression of a gene in a parent cell prior to minicell formation
and/or in segregated minicells. Such manipulations may result in
increased or decreased production, and/or changes in the
intramolecular and intermolecular functions, of a protein in a
minicell or its parent cell. The techniques may be employed to
increase the efficiency of gene expression and protein production
in parent cells prior to minicell formation and/or in segregated
minicells.
[0366] II. C.6.a. Escherichia coli Genes
[0367] By way of non-limiting example, manipulation of the abpS
gene or gene product from E. coli, or homologs of this gene or gene
product found in other members of the Prokaryotes, Eukaryotes,
Archaebacteria and/or organelles (e.g., mitochondria, chloroplasts,
plastids and the like) may be employed to increase the efficiency
of gene expression and protein production in parent cells prior to
minicell formation and/or in segregated minicells (Celis, R. T.
1982. Mapping of two loci affecting the synthesis and structure of
a periplasmic protein involved in arginine and ornithine transport
in Escherichia coli K-12. J. Bacteriol. 151(3):1314-9).
[0368] In addition to abpS, other exemplary E. coli genes encoding
factors involved in the transport of inducers, inhibitors and other
compounds include, but are not limited to, araE (Khlebnikov, A., et
al. 2001. Homogeneous expression of the P(BAD) promoter in
Escherichia coli by constitutive expression of the low-affinity
high-capacity AraE transporter. Microbiology. 147(Pt 12):3241-7);
araG (Kehres, D. G., and Hogg, R. W. 1992. Escherichia coli K12
arabinose-binding protein mutants with altered transport
properties. Protein Sci. 1(12): 1652-60); araH (Id.); argP (Celis,
R. T. 1999. Repression and activation of arginine transport genes
in Escherichia coli K 12 by the ArgP protein. J. Mol Biol.
17;294(5):1087-95); aroT(aroR, trpR) (Edwards, R. M., and Yudkin,
M. D. 1982. Location of the gene for the low-affinity
tryptophan-specific permease of Escherichia coli. Biochem. J.
204(2):617-9); artI (Wissenbach, U., et al. 1995. A third
periplasmic transport system for L-arginine in Escherichia coli:
molecular characterization of the artPIQMJ genes, arginine binding
and transport. Mol. Microbiol. 17(4):675-86); artJ (Id.); artM
(Id.); artP (Id.); artQ (Id.); bioP (bir, birB) (Campbell, A., et
al. Biotin regulatory (bir) mutations of Escherichia coli. 1980. J.
Bacteriol. 142(3):1025-8); brnQ (hrbA) (Yamato, I., and Anraku, Y.
1980. Genetic and biochemical studies of transport systems for
branched-chain amino acids in Escherichia coli K-12: isolation and
properties of mutants defective in leucine-repressible transport
activities. J. Bacteriol. 144(1):36-44); brnR (Id.); brnS (Id.);
brnT (Id.); btuC (Friedrich, M. J., et al. 1986. Nucleotide
sequence of the btuCED genes involved in vitamin B12 transport in
Escherichia coli and homology with components of
periplasmic-binding-protein-dependent transport systems. J.
Bacteriol. 167(3):928-34); btuD (Id.) (Friedrich, M. J., et al.
1986. Nucleotide sequence of the btuCED genes involved in vitamin
B12 transport in Escherichia coli and homology with components of
periplasmic-binding-prot- ein-dependent transport systems. J.
Bacteriol. 167(3):928-34); caiT (Eichler, K. 1994. Molecular
characterization of the cai operon necessary for carnitine
metabolism in Escherichia coli. Mol. Microbiol. 13(5):775-86); celA
(Parker, L. L., and Hall, B. G. 1990. Characterization and
nucleotide sequence of the cryptic cel operon of Escherichia coli
K12. Genetics. 124(3):455-71); celB (Id.); celC (Id.); citA (Berlyn
et al., "Linkage Map of Escherichia coli K-12, Edition 9," Chapter
109 in: Escherichia coli and Salmonella typhimurium: Cellular and
Molecular Biology, 2nd Ed., Neidhardt, Frederick C., Editor in
Chief, American Society for Microbiology, Washington, D.C., 1996,
Volume 2, pages 1715-1902, and references cited therein); citB
(Id.); codB (Danielsen, S., et al. 1992. Characterization of the
Escherichia coli codBA operon encoding cytosine permease and
cytosine deaminase. Mol. Microbiol. 6(10):1335-44); cysA
(Karbonowska, H., et al. 1977. Sulphate permease of Escherichia
coli K12. Acta. Biochim. Pol. 24(4):329-34); cysU (cysT) (Sirko,
A., et al. 1995. Sulfate and thiosulfate transport in Escherichia
coli K-12: evidence for a functional overlapping of sulfate- and
thiosulfate-binding proteins. J. Bacteriol. 177(14):4134-6); cysW
(Id.); dctA (Lo, T. C., and Bewick, M. A. 1978. The molecular
mechanisms of dicarboxylic acid transport in Escherichia coli K12.
The role and orientation of the two membrane-bound dicarboxylate
binding proteins. J. Biol. Chem. 10;253(21):7826-31); dctB (Id.);
dcuA (genA) (Six, S., et al. 1994. Escherichia coli possesses two
homologous anaerobic C4-dicarboxylate membrane transporters (DcuA
and DcuB) distinct from the aerobic dicarboxylate transport system
(Dct). J. Bacteriol. 176(21):6470-8); dcuB (genf) (.); dgoT (Berlyn
et al., "Linkage Map of Escherichia coli K-12, Edition 9," Chapter
109 in: Escherichia coli and Salmonella typhimurium: Cellular and
Molecular Biology, 2nd Ed., Neidhardt, Frederick C., Editor in
Chief, American Society for Microbiology, Washington, D.C., 1996,
Volume 2, pages 1715-1902, and references cited therein); exuT
(Nemoz, G., et al. 1976. Physiological and genetic regulation of
the aldohexuronate transport system in Escherichia coli. J.
Bacteriol. 127(2):706-18); fepD (Ozenberger, B. A., et al. 1987.
Genetic organization of multiple fep genes encoding ferric
enterobactin transport functions in Escherichia coli. J. Bacteriol.
169(8):3638-46); fepG (Chenault, S. S., and Earhart, C. F. 1991.
Organization of genes encoding membrane proteins of the Escherichia
coli ferrienterobactin permease. Mol. Microbiol. 5(6): 1405-13);
fucP (prd) (Chen, Y. M. 1987. The organization of the fuc regulon
specifying L-fucose dissimilation in Escherichia coli K12 as
determined by gene cloning. Mol. Gen. Genet. 210(2):331-7); glnP
(Masters, P. S., and Hong, J. S. 1981. Genetics of the glutamine
transport system in Escherichia coli. J. Bacteriol. 147(3):805-19);
glnQ (Nohno, T. 1986. Cloning and complete nucleotide sequence of
the Escherichia coli glutamine permease operon (glnHPQ). Mol. Gen.
Genet. 205(2):260-9); glnR (Masters, P. S., and Hong, J. S. i981.
Genetics of the glutamine transport system in Escherichia coli. J.
Bacteriol. 147(3):805-19); glpT (Boos, W., et al. 1977.
Purification and properties of a periplasmic protein related to
sn-glycerol-3-phosphate transport in Escherichia coli. Eur. J.
Biochem. 72(3):571-81); gltP (Deguchi, Y., et al. 1989. Molecular
cloning of gltS and gltP, which encode glutamate carriers of
Escherichia coli. B. J. Bacteriol. 171(3):1314-9); gltS (Id.); gntR
(Bachi, B., and Kornberg, H. L. 1975. Genes involved in the uptake
and catabolism of gluconate by Escherichia coli. J. Gen. Microbiol.
90(2):321-35); gntS (Id.); gntT (gntM, usgA) (Id.); gntU (Tong, S.
1996. Cloning and molecular,genetic characterization of the
Escherichia coli gntR, gntK, and gntU genes of GntI, the main
system for gluconate metabolism. J. Bacteriol. 178(11):3260-9);
hisM (Berlyn et al., "Linkage Map of Escherichia coli K-12, Edition
9," Chapter 109 in: Escherichia coli and Salmonella typhimurium:
Cellular and Molecular Biology, 2nd Ed., Neidhardt, Frederick C.,
Editor in Chief, American Society for Microbiology, Washington,
D.C., 1996, Volume 2, pages 1715-1902, and references cited
therein); hisP (Id.); hisQ (Id.); livG (hrbB, hrbC, hrbD) (Landick,
R., et al. 1980. Regulation of high-affinity leucine transport in
Escherichia coli. J. Supramol. Struct. 14(4):527-37); livH (hrbB,
hrbC, hrbD) (Id.); livJ (hrbB, hrbC, hrbD) (Id.); livK (hrbB, hrbC,
hrbD) (Id.); livM (Id.); lldP (lctP) (Dong, J. M., et al. 1993.
Three overlapping lct genes involved in L-lactate utilization by
Escherichia coli. J. Bacteriol. 175(20):6671-8); lysP (cadR)
(Steffes, C., et al. 1992. The lysP gene encodes the
lysine-specific permease. J. Bacteriol. 174(10):3242-9); malF
(malB) (Bavoil, P., et al. 1980. Identification of a cytoplasmic
membrane-associated component of the maltose transport system of
Escherichia coli. J. Biol. Chem. 255(18):8366-9); maiG (malB)
(Dassa, E., and Hofnung, M. 1985. Sequence of gene maiG in E. coli
K12: homologies between integral membrane components from binding
protein-dependent transport systems. EMBO J. 4(9):2287-93); malK
(malB) (Id.); mglC (PMG, mglP) (Harayama, S. 1983. Characterization
of the mgl operon of Escherichia coli by transposon mutagenesis and
molecular cloning. J. Bacteriol. 153(1):408-15); nanT(Vimr, E. R.,
and Troy, F. A. 1985. Identification of an inducible catabolic
system for sialic acids (nan) in Escherichia coli. J. Bacteriol.
164(2):845-53); nupC (cru) (Craig, J. E., et al. 1994. Cloning of
the nupC gene of Escherichia coli encoding a nucleoside transport
system, and identification of an adjacent insertion element, IS
186. Mol. Microbiol. 11(6):1159-68); nupG (Westh Hansen, S. E., et
al. 1987. Studies on the sequence and structure of the Escherichia
coli K-12 nupG gene, encoding a nucleoside-transport system. Eur.
J. Biochem. 168(2):385-91); panF (Vallari, D. S., and Rock, C. O.
1985. Isolation and characterization of Escherichia coli
pantothenate permease (panF) mutants. J. Bacteriol. 164(1):
136-42); potA (Kashiwagi, K., et al. 1993. Functions of potA and
potD proteins in spermidine-preferential uptake system in
Escherichia coli. J. Biol. Chem. 268(26):19358-63); potG
(Pistocchi, R., et al. 1993. Characteristics of the operon for a
putrescine transport system that maps at 19 minutes on the
Escherichia coli chromosome. J. Biol. Chem. 268(1): 146-52); potH
(Id.); potI (Id.); proP (Wood, J. M., and Zadworny, D. 1980.
Amplification of the put genes and identification of the put gene
products in Escherichia coli K12. Can. J. Biochem. 58(10):787-96);
proT (Id.); proV (proU) (Faatz, E., et al. 1988. Cloned structural
genes for the osmotically regulated binding-protein-dependent
glycine betaine transport system (ProU) of Escherichia coli K-12.
Mol. Microbiol. 2(2):265-79); proW (proU) (Id.); proX (proU) (Id.);
pstA (R2pho, phoR2b, phoT) (Amemura, M., et al. 1985. Nucleotide
sequence of the genes involved in phosphate transport and
regulation of the phosphate regulon in Escherichia coli. J. Mol.
Biol. 184(2):241-50); pstB (phoT) (Id.); pstC (phoW) (Rao, N. N.,
and Torriani, A. 1990. Molecular aspects of phosphate transport in
Escherichia coli. Mol. Microbiol. 4(7):1083-90); pstS (R2pho, nmpA,
phoR2a, phos) (Makino, K., et al. 1988. Regulation of the phosphate
regulon of Escherichia coli. Activation of pstS transcription by
PhoB protein in vitro. J. Mol. Biol. 203(1):85-95); purP (Burton,
K. 1994. Adenine transport in Escherichia coli. Proc. R. Soc. Lond.
B. Biol. Sci. 255(1343):153-7); putP (Stalmach, M. E., et al. 1983.
Two proline porters in Escherichia coli K-12. J. Bacteriol.
156(2):481-6); rbsA (rbsP, rbsT) (Iida, A., et al. 1984. Molecular
cloning and characterization of genes required for ribose transport
and utilization in Escherichia coli K-12. J. Bacteriol.
158(2):674-82); rbsC (rbsP, rbsT) (Id.); rbsD (rbsP) (Id.); rhaT
(Baldoma, L., et al. 1990. Cloning, mapping and gene product
identification of rhaT from Escherichia coli K12. FEMS Microbiol.
Lett. 60(1-2):103-7); sdaC(Shao, Z., et al. 1994. Sequencing and
characterization of the sdaC gene and identification of the sdaCB
operon in Escherichia coli K12. Eur. J. Biochem. 222(3):901-7);
tnaB (trpP) (Sarsero, J. P., et al. 1991. A new family of integral
membrane proteins involved in transport of aromatic amino acids in
Escherichia coli. J. Bacteriol. 173(10):3231-4); tyrR (Whipp, M.
J., and Pittard, A. J. 1977. Regulation of aromatic amino acid
transport systems in Escherichia coli K-12. J. Bacteriol.
132(2):453-61); ugpC (Schweizer, H., and Boos, W. 1984.
Characterization of the ugp region containing the genes for the
phoB dependent sn-glycerol-3-phosphate transport system of
Escherichia coli. Mol. Gen. Genet. 197(1): 161-8); uhpT (Weston, L.
A., and Kadner, R. J. 1987. Identification of uhp polypeptides and
evidence for their role in exogenous induction of the sugar
phosphate transport system of Escherichia coli K-12. J. Bacteriol.
169(8):3546-55); and xylF (xylT) (Sumiya, M., et al. 1995.
Molecular genetics of a receptor protein for D-xylose, encoded by
the gene xylF, in Escherichia coli. Receptors Channels. 3(2):
117-28).
[0369] II.C.6.b. Bacillus subtilis Genes
[0370] By way of non-limiting example, manipulation of the aapA
gene or gene product from B. subtilis, or homologs of this gene or
gene product found in other members of the Prokaryotes, Eukaryotes,
Archaebacteria and/or organelles (e.g., mitochondria, chloroplasts,
plastids and the like) may be employed to increase the efficiency
of gene expression and protein production in parent cells prior to
minicell formation and/or in segregated minicells (Sohenshein, A.
L., J. A. Hoch, and R. Losick (eds.) 2002. Bacillus subtilis and
its closest relatives: from genes to cells. American Society for
Microbiology, Washington D.C.).
[0371] In addition to aapA, other exemplary B. substilis genes
encoding factors involved in the transport of inducers, inhibitors
and other compounds include, but are not limited to, amyC
(Sekiguchi, J., et al. 1975. Genes affecting the productivity of
alpha-amylase in Bacillus subtilis. J. Bacteriol. 121(2):688-94);
amyD (Id.); araE (Sa-Nogueira, I., and Mota, L. J. 1997. Negative
regulation of L-arabinose metabolism in Bacillus subtilis:
characterization of the araR (araC) gene. J. Bacteriol.
179(5):1598-608); araN (Sa-Nogueira, I., et al. 1997. The Bacillus
subtilis L-arabinose (ara) operon: nucleotide sequence, genetic
organization and expression. Microbiology. 143 (Pt 3):957-69); araP
(Id.); araQ (Id.); csbC (Akbar, S., et al. 1999. Two genes from
Bacillus subtilis under the sole control of the general stress
transcription factor sigmaB. Microbiology. 145 (Pt 5):1069-78);
cysP (Mansilla, M. C., and de Mendoza, D. 2000. The Bacillus
subtilis cysP gene encodes a novel sulphate permease related to the
inorganic phosphate transporter (Pit) family. Microbiology. 146 (Pt
4):815-21); dctB (Sohenshein, A. L., J. A. Hoch, and R. Losick
(eds.) 2002. Bacillus subtilis and its closest relatives: from
genes to cells. American Society for Microbiology, Washington
D.C.); exuT (Rivolta, C., et al. 1998. A 35.7 kb DNA fragment from
the Bacillus subtilis chromosome containing a putative 12.3 kb
operon involved in hexuronate catabolism and a perfectly
symmetrical hypothetical catabolite-responsive element.
Microbiology. 144 (Pt 4):877-84); gabP (Ferson, A. E., et al. 1996.
Expression of the Bacillus subtilis gabP gene is regulated
independently in response to nitrogen and amino acid availability.
Mol. Microbiol. 22(4):693-701); gamP (Sohenshein, A. L., J. A.
Hoch, and R. Losick (eds.) 2002. Bacillus subtilis and its closest
relatives: from genes to cells. American Society for Microbiology,
Washington D.C.); glcP (Paulsen, I. T., et al. 1998.
Characterization of glucose-specific catabolite
repression-resistant mutants of Bacillus subtilis: identification
of a novel hexose:H+ symporter. J. Bacteriol. 180(3):498-504); glcU
(Sohenshein, A. L., J. A. Hoch, and R. Losick (eds.) 2002. Bacillus
subtilis and its closest relatives: from genes to cells. American
Society for Microbiology, Washington D.C.); glnH (Id.); glnM (Id);
glnP (Sohenshein, A. L., J. A. Hoch, and R. Losick (eds.) 2002.
Bacillus subtilis and its closest relatives: from genes to cells.
American Society for Microbiology, Washington D.C.); glnQ (Id.);
glpT(Nilsson, R. P., et al. 1994. The glpT and glpQ genes of the
glycerol regulon in Bacillus subtilis. Microbiology. 140 (Pt
4):723-30); gltP (Tolner, B., et al. 1995. Characterization of the
proton/glutamate symport protein of Bacillus subtilis and its
functional expression in Escherichia coli. J. Bacteriol.
177(10):2863-9); gltT (Tolner, B., et al. 1995. Characterization of
the proton/glutamate symport protein of Bacillus subtilis and its
functional expression in Escherichia coli. J. Bacteriol.
177(10):2863-9); gntP (Reizer, A., et al. Analysis of the gluconate
(gnt) operon of Bacillus subtilis. Mol. Microbiol. 5(5): 1081-9);
gutP (Sohenshein, A. L., J. A. Hoch, and R. Losick (eds.) 2002.
Bacillus subtilis and its closest relatives: from genes to cells.
American Society for Microbiology, Washington D.C.); hutM (Oda, M.,
et al. 1988. Cloning and nucleotide sequences of histidase and
regulatory genes in the Bacillus subtilis hut operon and positive
regulation of the operon. J. Bacteriol. 170(7):3199-205); iolF
(Sohenshein, A. L., J. A. Hoch, and R. Losick (eds.) 2002. Bacillus
subtilis and its closest relatives: from genes to cells. American
Society for Microbiology, Washington D.C.); kdgT (Pujic, P., et al.
1998. The kdgRKAT operon of Bacillus subtilis: detection of the
transcript and regulation by the kdgR and ccpA genes. Microbiology.
144 (Pt 11):3111-8); lctP (Cruz, Ramos H., et al. 2000.
Fermentative metabolism of Bacillus subtilis: physiology and
regulation of gene expression. J. Bacteriol. 182(11):3072-80); maeN
(Ito, M., et al. 2000. Effects of nonpolar mutations in each of the
seven Bacillus subtilis mrp genes suggest complex interactions
among the gene products in support of Na(+) and alkali but not
cholate resistance. J. Bacteriol. 182(20):5663-70); malP
(Sohenshein, A. L., J. A. Hoch, and R. Losick (eds.) 2002. Bacillus
subtilis and its closest relatives: from genes to cells. American
Society for Microbiology, Washington D.C.); manP (Id.); mleN (Id.);
nasA (Ogawa, K., et al. 1995. The nasB operon and nasA gene are
required for nitrate/nitrite assimilation in Bacillus subtilis. J.
Bacteriol. 177(5): 1409-13); nupC (Sohenshein, A. L., J. A. Hoch,
and R. Losick (eds.) 2002. Bacillus subtilis and its closest
relatives: from genes to cells. American Society for Microbiology,
Washington D.C.); opuAB (Kempf, B., et al. 1997. Lipoprotein from
the osmoregulated ABC transport system OpuA of Bacillus subtilis:
purification of the glycine betaine binding protein and
characterization of a functional lipidless mutant. J. Bacteriol.
179(20):6213-20); opuBA (Sohenshein, A. L., J. A. Hoch, and R.
Losick (eds.) 2002. Bacillus subtilis and its closest relatives:
from genes to cells. American Society for Microbiology, Washington
D.C.); pbuG (Saxild, H. H., et al. 2001. Definition of the Bacillus
subtilis PurR operator using genetic and bioinformatic tools and
expansion of the PurR regulon with glyA, guaC, pbuG, xpt-pbuX,
yqhZ-folD, and pbuO. J. Bacteriol. 183(21):6175-83); pbuX (Saxild,
H. H., et al. 2001. Definition of the Bacillus subtilis PurR
operator using genetic and bioinformatic tools and expansion of the
PurR regulon with glyA, guaC, pbuG, xpt-pbuX, yqhZ-folD, and pbuO.
J. Bacteriol. 183(21):6175-83), pstC (Takemaru, K., et al. 1996. A
Bacillus subtilis gene cluster similar to the Escherichia coli
phosphate-specific transport (pst) operon: evidence for a tandemly
arranged pstB gene. Microbiology. 142 (Pt 8):2017-20); pstS (Qi,
Y., et al. 1997. The pst operon of Bacillus subtilis has a
phosphate-regulated promoter and is involved in phosphate transport
but not in regulation of the pho regulon. J. Bacteriol.
179(8):2534-9); pucJ (Schultz, A. C., et al. 2001. Functional
analysis of 14 genes that constitute the purine catabolic pathway
in Bacillus subtilis and evidence for a novel regulon controlled by
the PucR transcription activator. J. Bacteriol. 183(11):3293-302);
pucK (Schultz, A. C., et al. 2001. Functional analysis of 14 genes
that constitute the purine catabolic pathway in Bacillus subtilis
and evidence for a novel regulon controlled by the PucR
transcription activator. J. Bacteriol. 183(11):3293-302); pyrP
(Turner, R. J., et al. 1994. Regulation of the Bacillus subtilis
pyrimidine biosynthetic (pyr) gene cluster by an autogenous
transcriptional attenuation mechanism. J. Bacteriol.
176(12):3708-22); rbsB (Sohenshein, A. L., J. A. Hoch, and R.
Losick (eds.) 2002. Bacillus subtilis and its closest relatives:
from genes to cells. American Society for Microbiology, Washington
D.C.); rbsC (Sohenshein, A. L., J. A. Hoch, and R. Losick (eds.)
2002. Bacillus subtilis and its closest relatives: from genes to
cells. American Society for Microbiology, Washington D.C.); rbsD
(Id.); rocC (Gardan, R., et al. 1995. Expression of the rocDEF
operon involved in arginine catabolism in Bacillus subtilis. J.
Mol. Biol. 23;249(5):843-56); rocE (Gardan, R., et al. 1995.
Expression of the rocDEF operon involved in arginine catabolism in
Bacillus subtilis. J. Mol. Biol. 23;249(5):843-56); ssuA (Coppee,
J. Y., et al. 2001. Sulfur-limitation-regulated proteins in
Bacillus subtilis: a two-dimensional gel electrophoresis study.
Microbiology. 147(Pt 6):1631-40); ssuB (van der Ploeg, J. R., et
al. 1998. Bacillus subtilis genes for the utilization of sulfur
from aliphatic sulfonates. Microbiology. 144 (Pt 9):2555-61); ssuC
(van der Ploeg, J. R., et al. 1998. Bacillus subtilis genes for the
utilization of sulfur from aliphatic sulfonates. Microbiology. 144
(Pt 9):2555-61); treP (Yamamoto, H., et al. 1996. Cloning and
sequencing of a 40.6 kb segment in the 73 degrees-76 degrees region
of the Bacillus subtilis chromosome containing genes for trehalose
metabolism and acetoin utilization. Microbiology. 142 (Pt
11):3057-65); xynP (Sohenshein, A. L., J. A. Hoch, and R. Losick
(eds.) 2002. Bacillus subtilis and its closest relatives: from
genes to cells. American Society for Microbiology, Washington
D.C.); ybaR (Id.); ybgF (Id.); ybgH (Id.); ycbE (Id.); ycgO (Id.);
yckI (Id.); yckJ (Id.); yckK (Id.); ydgF (Id.); yecA (Borriss, R.,
et al. 1996. The 52 degrees-55 degrees segment of the Bacillus
subtilis chromosome: a region devoted to purine uptake and
metabolism, and containing the genes cotA, gabP and guaA and the
pur gene cluster within a 34960 bp nucleotide sequence.
Microbiology. 142 (Pt 11):3027-31); yesP (Sohenshein, A. L., J. A.
Hoch, and R. Losick (eds.) 2002. Bacillus subtilis and its closest
relatives: from genes to cells. American Society for Microbiology,
Washington D.C.); yesQ (Id.): yflS (Id.); yhcL (Id.); yhjB (Id.);
yjkB (Id.); ykbA (Id.); yoaB (Id.); yocN (Id.); yodF (Id.); yojA
(Id.); yqiY (Id.); ytlD (Id.); ytlP (Id.); ytmL (Id.); ytmM (Id.);
ytnA (Id.); yurM (Id.); yurN (Id.); yvbW (Id.); yvdH (Id.); yvdI
(Id.); yveA (Pereira, Y., et al. 2001. The yveB gene, Encoding
endolevanase LevB, is part of the sacB-yveB-yveA levansucrase
tricistronic operon in Bacillus subtilis. Microbiology. 147(Pt
12):3413-9); yvfH (Sohenshein, A. L., J. A. Hoch, and R. Losick
(eds.) 2002. Bacillus subtilis and its closest relatives: from
genes to cells. American Society for Microbiology, Washington
D.C.); yvfL (Id.); yvfM (Id.); yvgM (Id.); yvrO (Id.); yvsH (Id.);
ywbF (Id.); ywcJ (Id.); ywoD (Id.); ywoE (Id.); yxeN (Id.); and
yxeR (Id.).
[0372] II.C.7. Catabolite Repression
[0373] Included in the design of the invention are techniques that
increase the efficiency of gene expression and protein production
in minicells. By way of non-limiting example, these techniques may
include utilization and/or modification of factors and systems
involved in the synthesis, degradation or transport of catabolites
that modulate the genetic expression of a preselected protein. Such
manipulations may result in increased or decreased production,
and/or changes in the intramolecular and intermolecular functions,
of a protein in a minicell or its parent cell; in the latter
instance, the protein may be one that is desirably retained in
segregated minicells.
[0374] By way of non-limiting example, it is known in the art to
use promoters from the trp, cst-1, and llp operons of E. coli,
which are induced by, respectively, reduced tryptophan levels,
glucose starvation, and lactose. Manipulation of the catabolites
tryptophan, glucose and lactose, respectively, will influence the
degree of expression of genes operably linked to these promoters.
(Makrides, Savvas C., Strategies for Achieving High-Level
Expression of Genes in Escherichia coli. Microbiological Reviews.
1996. 60:512-538.)
[0375] As another non-limiting example, expression elements from
the E. coli L-arabinose (ara) operon are used in expression
systems. AraC is a protein that acts as a repressor of ara genes in
the absence of arabinose, and also as an activator of ara genes
when arabinose is present. Induction of ara genes also involves
cAMP, which modulates the activity of CRP (cAMP receptor protein),
which in turn is required for full induction of ara genes (Schleif,
Robert, Regulation of the L-arabinose operon of Escherichia coli.
2000. TIG 16:559-564. Tius, maximum expression from an ara-based
expression system is achieved by adding cAMP and arabinose to host
cells, and optimizing the expression of CRP in hostcells.
[0376] As one example, manipulation of the acpS gene or gene
product of E. coli (Pollacco M. L., and J. E. Cronan Jr. 1981. A
mutant of Escherichia coli conditionally defective in the synthesis
of holo-[acyl carrier protein]. J. Biol. Chem. 256:5750-5754); or
homologs of this gene or its gene product found in other
prokaryotes, eukaryotes, archaebacteria or organelles
(mitochondria, chloroplasts, plastids and the like) may be employed
to increase the efficiency of gene expression and protein
production in parent cells prior to minicell formation and/or in
segregated minicells.
[0377] In addition to acpS, other exemplary E. coli genes include
the b2383 gene (Berlyn et al., "Linkage Map of Escherichia coli
K-12, Edition 9," Chapter 109 in: Escherichia coli and Salmonella
typhimurium: Cellular and Molecular Biology, 2nd Ed., Neidhardt,
Frederick C., Editor in Chief, American Society for Microbiology,
Washington, D.C., 1996, Volume 2, pages 1715-1902, and references
cited therein. b2387 gene; the celA gene (Parker L. L., and B. G.
Hall. 1990. Characterization and nucleotide sequence of the cryptic
cel operon of Escherichia coli K12. Genetics. 124:455-471); the
celB gene (Cole S. T., and B. Saint-Joanis, and A. P. Pugsley.
1985. Molecular characterisation of the colicin E2 operon and
identification of its products. Mol Gen Genet. 198:465-472); the
celC gene (Parker L. L., and B. G. Hall. 1990. Characterization and
nucleotide sequence of the cryptic cel operon of Escherichia coli
K12. Genetics. 124:455-471); the cmtB gene (Ezhova N. M., Zaikina,
N. A, Shataeva, L. K., Dubinina, N. I., Ovechkina, T. P. and J. V.
Kopylova. [Sorption properties of carboxyl cation exchangers with a
bacteriostatic effect]. 1980. Prikl Bioikhim Mikrobiol.
16:395-398); the creB gene (Berlyn et al., "Linkage Map of
Escherichia coli K-12, Edition 9," Chapter 109 in: Escherichia coli
and Salmonella typhimurium: Cellular and Molecular Biology, 2nd
Ed., Neidhardt, Frederick C., Editor in Chief, American Society for
Microbiology, Washington, D.C., 1996, Volume 2, pages 1715-1902,
and references cited therein; the creC gene (Wanner B. L. Gene
regulation by phosphate in enteric bacteria. 1993. J Cell Biochem.
51:47-54); the crp gene (Sabourn D., and J. Beckwith. Deletion of
the Escherichia coli crp gene. 1975. J Bacteriology. 122:338-340);
the crr (gsr, iex, tgs, treD) gene (Jones-Mortimer M. C., and H. L.
Kornberg, and r. Maltby, and P. D. Watts. Role of the crr-gene in
glucose uptake by Escherichia coli. 1977. FEBS Lett. 74:17-19); the
cya gene (Bachi B., and H. L. Kornberg. Utilization of gluconate by
Escherichia coli. A role of adenosine 3':5'-cyclic monophosphate in
the induction of gluconate catabolism. 1975. Biochem J.
150:123-128); the fruA gene (Prior T. I., and H. L. Kornberg.
Nucleotide sequence of fruA, the gene specifying enzyme Iifru of
the phosphoenopyruvate-dependent sugar phosphotranssferase system
in Escherichia coli K12. 1988. J Gen Microbiol. 134:2757-2768); the
fruB gene (Bol'shakova T. N. and R. S. Erlagaeva, and Dobrynina
Oiu, and V. N. Gershanovich. [Mutation fruB in the fructose regulon
affeting beta-galactosidase synthesis and adenylate cyclase
activity of E. coli K12]. 1988. Mol Gen Mikrobiol virusol.
3:33-39); the fruR gene (Jahreis K., and P. W. Postma, and J. W.
Lengeler. Nucleotide sequence of the ilvH-frR gene region of
Escherichia coli K12 and Salmonella typhimurium LT2. 1991. Mol Gen
Genet. 226:332-336); the frvA gene (Berlyn et al., "Linkage Map of
Escherichia coli K-12, Edition 9," Chapter 109 in: Escherichia coli
and Salmonella typhimurium: Cellular and Molecular Biology, 2nd
Ed., Neidhardt, Frederick C., Editor in Chief, American Society for
Microbiology, Washington, D.C., 1996, Volume 2, pages 1715-1902,
and references cited therein); the ftwB gene (Id.); the rvD gene
(Id.); the gatB gene (Nobelmann B., and J. W. Lengeler. Molecular
analysis of the gat genes from Escherichia coli and of their roles
in galactitol transport and metabolism. 1996. J Bacteriol.
178:6790-6795); the gatc gene (Id.); the malX gene (Reidel J., W.
Boos. The malX malY operon of Escherichia coli encodes a novel
enzyme II of the photophotransferase system recognizing glucose and
maltose and an enzyme abolishing the endogenous induction of the
maltose system. 1991. J Bacteriol. 173:4862-4876); the manX (gptB,
mpt, ptsL, ptsM, ptsX, manlll) gene (Plumbridge J., and A. Kolb.
CAP and Nag repressor binding to the regulatory regions of the
nagE-B and manX genes of Escherichia coli. 1991. J Mol Biol.
217:661-679); the manY (pel, ptsM, ptsP, manPII) gene (Henderson P.
J., and R. A. Giddens, and M. C. Jones-Mortimer. Transport of
galactose, glucose and their molecular analogues by Escherichia
coli K12. 1977. Biochem J. 162:309-320); the manZ (gptB, mpt, ptsM,
ptsX) gene (Williams N., and D. K. Fox, and C. Shea and S. Roseman.
Pel, the protein that permits lambda DNA penetration of Escherichia
coli, is encoded by a gene in ptsM and is required for mannose
utilization by the phosphotransferase system. 1986. Proc Natl Acad
Sci USA. 83:8934-8938); the mtlA gene (Lengeler J. Mutations
affecting transport of the hexitols D-mannitol, D-glucitol, and
galactitol in Escherichia coli K-12: isolation and mapping. 1975. J
Bacteriol. 124:26-38.); the nagE (pstn) gene (Rogers M. J., and T.
Ohgi, and J. Plumbridge, and D. Soll. Nucleotide sequences of the
Escherichia coli nagE and nagb genes: the structural genes for the
N-acetylglucosamine transport protein of the bacterial
phosphoenolpyruvate: sugar phosphotransferase system and for
glucosamine-6-phosphate deaminase. 1988. Gene. 62:197-207); the
pstA gene (Cox G. B., H. Rosenberg, and J. A. Downie, and S.
Silver. Genetic analysis of mutants affected in the Pst inorganic
phosphate transport system. 1981. J Bacteriol. 148:1-9); the pstB
(gutB) gene (Id.); the pstG gene (Cox G. B., H. Rosenberg, and J.
A. Downie, and S. Silver. Genetic analysis of mutants affected in
the Pst inorganic phosphate transport system. 1981. J Bacteriol.
148:1-9); the psiH gene (Id.); the pstI gene (Id.); the pstN gene
(Id.); the pstO gene (Id.); the ptxA (yifU) gene (Berlyn et al.,
"Linkage Map of Escherichia coli K-12, Edition 9," Chapter 109 in:
Escherichia coli and Salmonella typhimurium: Cellular and Molecular
Biology, 2nd Ed., Neidhardt, Frederick C., Editor in Chief,
American Society for Microbiology, Washington, D.C., 1996, Volume
2, pages 1715-1902, and references cited therein); the sgcA (yjhL)
gene (Id.); the sgcC (yjhN) gene (Id.); the treB gene (Boos W., U.
Ehmann, H. Forkl, W. Klein, M. Rimmele, and P. Postma. Trehalose
transport and metabolism in Escherichia coli. 1990. J. Bacteriol.
172:3450-3461); the usg gene (Arps P. J., and M. E. Winkler ME.
Structural analysis of the Escherichia coli K-12 hisT operon by
using a kanamycin resistance cassette. 1987. J Bacteriol.
169:1061-1070); the wcaD gene (Mao Y., and M. P. Doyle, and J.
Chen. Insertion mutagenisis of wca reduces acide and heat tolerance
of enterohemorrhagic Escherichia coli O157:H7. 2001. J Bacteriol.
183:3811-3815); the yadI gene (Berlyn et al., "Linkage Map of
Escherichia coli K-12, Edition 9," Chapter 109 in: Escherichia coli
and Salmonella typhimurium: Cellular and Molecular Biology, 2nd
Ed., Neidhardt, Frederick C., Editor in Chief, American Society for
Microbiology, Washington, D.C., 1996, Volume 2, pages 1715-1902,
and references cited therein); and the ycgC gene (Gutknecht R., and
R. Beutler, and L. F. Garcia-Alles, and U. Baumann, and B. Erni.
The dihydroxyacetone kinase of Escherichia coli utilizes a
phosphoprotein instead of ATP as phosphoryl donor. 2001. EMBO J.
20:2480-2486).
[0378] II.C.8. General Deletions and Modifications
[0379] Included in the design of the invention are techniques that
increase the efficiency of gene expression and protein production
in minicells. By way of non-limiting example, these techniques may
include modification or deletion of endogenous gene(s) from which
their respective gene product decreases the induction and
expression efficiency of a desired protein in the parent cell prior
to minicell formation and/or the segregated minicell. By way of
non-limiting example, these protein components may be the enzymes
that degrade chemical inducers of expression, proteins that have a
dominant negative affect upon a positive regulatory elements,
proteins that have proteolytic activity against the protein to be
expressed, proteins that have a negative affect against a chaperone
that is required for proper activity of the expressed protein,
and/or this protein may have a positive effect upon a protein that
either degrades or prevents the proper function of the expressed
protein. These gene products that require deletion or modification
for optimal protein expression and/or function may also be
antisense nucleic acids that have a negative affect upon gene
expression.
[0380] II.C.9. Cytoplasmic Redox State
[0381] Included in the design of the invention are techniques that
increase the efficiency of gene expression and functional protein
production in minicells. By way of non-limiting example, these
techniques may include modification of endogenous and/or exogenous
protein components that alter the redox state of the parental cell
cytoplasm prior to minicell formation and/or the segregated
minicell cytoplasm. By way of non-limiting example, this protein
component may be the product of the trxA, grx, dsbA, dsbB, and/or
dsbc genes from E. coli or homologs of this gene or gene product
found in other members of the Eubacteria, Eucarya or Archae (Mark
et al., Genetic mapping of trxA, a gene affecting thioredoxin in
Escherichia coli K12, Mol Gen Genet. 155:145-152, 1977; (Russel et
al., Thioredoxin or glutaredoxin in Escherichia coli is essential
for sulfate reduction but not for deoxyribonucleotide synthesis, J
Bacteriol. 172:1923-1929, 1990); Akiyama et al., In vitro catalysis
of oxidative folding of disulfide-bonded proteins by the
Escherichia coli dsbA (ppfA) gene product, J Biol Chem.
267:22440-22445, 1992); (Whitney et al., The DsbA-DsbB system
affects the formation of disulfide bonds in periplasmic but not in
intramembraneous protein domains, FEBS Lett. 332:49-51, 1993);
(Shevchik et al., Characterization of DsbC, a periplasmic protein
of Erwinia chrysanthemi and Escherichia coli with disulfide
isomerase activity, EMB J. 13:2007-2012, 1994). These applications
may, but are not limited to increased or decreased production,
increased or decreased intramolecular TrxA activity, increased or
decreased physiological function of the above-mentioned gene
products. By way of non-limiting example, increased production of
gene product (gene expression) may occur through increased gene
dosage (increased copy number of a given gene under the control of
the native or artificial promotor where this gene may be on a
plasmid or in more than one copy on the chromosome), modification
of the native regulatory elements, including, but not limited to
the promotor or operator region(s) of DNA, or ribosomal binding
sites on RNA, relevant repressors/silencers, relevant
activators/inhancers, or relevant antisense nucleic acid or nucleic
acid analog, cloning on a plasmid under the control of the native
or artificial promotor, and increased or decreased production of
native or artificial promotor regulatory elements) controlling
production of the gene. By way of non-limiting example, decreased
gene expression production may occur through modification of the
native regulatory elements, including, but not limited to the
promotor or operator region(s) of DNA, or ribosomal binding sites
on RNA, relevant repressors/silencers, relevant
activators/inhancers, or relevant antisense nucleic acid or nucleic
acid analog, through cloning on a plasmid under the control of the
native regulatory region containing mutations or an artificial
promotor, either or both of which resulting in decrease gene
expression, and through increased or decreased production of native
or artificial promotor regulatory element(s) controlling gene
expression. By definition, intramolecular activity refers to the
enzymatic function, structure-dependent function, e.g. the capacity
off a gene product to interact in a protein-protein,
protein-nucleic acid, or protein-lipid complex, and/or carrier
function, e.g. the capacity to bind, either covalently or
non-covalently small organic or inorganic molecules, protein(s)
carbohydrate(s), fatty acid(s), lipid(s), and nucleic acid(s). By
way of non-limiting example, alteration of intramolecular activity
may be accomplished by mutation of the gene, in vivo or in vitro
chemical modification of the gene product, inhibitor molecules
against the function of the gene product, e.g. competitive,
non-competitive, or uncompetitive enzymatic inhibitors, inhibitors
that prevent protein-protein, protein-nucleic acid, or
protein-lipid interactions, e.g. expression or introduction of
dominant-negative or dominant-positive or other protein
fragment(s), or other carbohydrate(s), fatty acid(s), lipid(s), and
nucleic acid(s) that may act directly or allosterically upon the
gene product, and/or modification of protein, carbohydrate, fatty
acid, lipid, or nucleic acid moieties that modify the gene or gene
product to create the functional protein. By definition,
physiological function refers to the effects resulting from an
intramolecular interaction between the gene product and other
protein, carbohydrate, fatty acid, lipid, nucleic acid, or other
molecule(s) in or on the cell or the action of a product or
products resulting from such an interaction.
[0382] By way of non-limiting example, physiological function may
be the act or result of intermolecular phosphorylation,
biotinylation, methylation, acylation, glycosylation, and/or other
signaling event; this function may be the result of
protein-protein, protein-nucleic acid, or protein-lipid interaction
resulting in a functional moiety; this function may be to interact
with the membrane to recruit other molecules to this compartment of
the cell; this function may be to regulate the transcription and/or
translation of trxA, other protein, or nucleic acid; and this
function may be to stimulate the function of another process that
is not yet described or understood.
[0383] II.C. 10. Transcriptional Terminators
[0384] Included in the design of the invention are techniques that
increase the efficiency of gene expression and protein production
in parental cell cytoplasm prior to minicell formation and/or the
segregated minicell cytoplasm. By way of non-limiting example,
these techniques may include modification of terminator regions of
DNA templates or RNA transcripts so that transcription and/or
translation of these nucleic acid regions will terminate at greater
efficiency. By way of non-limiting example, these techniques may
include stem-loop structures, consecutive translational
terminators, polyadenylation sequences, or increasing the
efficiency of rho-dependent termination. Stem loop structures may
include, but are not limited to, inverted repeats containing any
combination of deoxyribonucleic acid or ribonucleic acid molecule,
more than one such inverted repeat, or variable inverted repeats
such that the rate of transcriptional/translational termination may
be moderated dependent on nucleic acid and/or amino acid
concentration, e.g. the mechanism of regulatory attenuation
(Oxdender et al., Attenuation in the Escherichia coli tryptophan
operon: role of RNA secondary structure involving the tryptophan
codon region, Proc. Natl. Acad. Sci. 76:5524-5528, 1979). See also,
Yager and von Hippel, "Transcript Elongation and Termination in e.
Col. And Landick and Yanofsky, "Transcriptional Attenuation,"
Chapters 76 and 77, respectively in: Escherichia Coli and
Salmonella Typhimurium: Cellular and Molecular Biology, Neidhardt,
Frederick C., Editor in Chief, American Society for Microbiology,
Washington, D.C., 1987, Volume 1, pages 1241-1275 and 1276-1301,
respectively, and references cited therein.
[0385] II. C. 11. Ribosomal Targeting
[0386] Included in the design of the invention are techniques that
increase the efficiency of gene expression and protein production
in parental cell cytoplasm prior to minicell formation and/or the
segregated minicell cytoplasm. By way of non-limiting example,
these techniques may include modifications of endogenous and/or
exogenous ribosomal components such that ribosomes enter the
minicell segregates with higher efficiency. By way of non-limiting
example, these techniques may include increasing the copy number of
ribosomal binding sites on plasmid or like structure to recruit
more ribosomal components or increase the synthesis of ribosomal
subunits prior to segregation (Mawn et al., Depletion of free 30S
ribosomal subunits in Escherichia coli by expression of RNA
containing Shine-Dalgarno-like sequences, J. Bacteriol.
184:494-502, 2002). This construct may also include the use of
plasmid expressed translation initiation factors to assist
ribosomal segregation (Celano et al., Interaction of Escherichia
coli translation-initiation factor IF-1 with ribosomes, Eur. J.
Biochem. 178:351-355 1988). See also Hoopes and McClure,
"Strategies in Regulation of Transcription Initiation," Chapter 75
in: Escherichia Coli and Salmonella Typhimurium: Cellular and
Molecular Biology, Neidhardt, Frederick C., Editor in Chief,
American Society for Microbiology, Washington, D.C., 1987, Volume
2, pages 1231-1240, and references cited therein.
[0387] II.C.12. Proteases
[0388] Included in the design of the invention are techniques that
increase the efficiency of gene expression and protein production
in minicells. By way of non-limiting example, these techniques may
include utilization and/or modification of endogenous and/or
exogenous proteases. Such manipulations may result in increased or
decreased production, and/or changes in the intramolecular and
intermolecular functions, of a protein in a minicell or its parent
cell; in the latter instance, the protein may be one that is
desirably retained in segregated minicells.
[0389] The production or activity of a desired protein gene product
may be increased by decreasing the level and/or activity of a
protease that acts upon the desired protein. The production or
activity of a desired protein gene product may be increased by
increasing the level and/or activity of a protease that acts upon a
protein that inhibits the production or function of the desired
protein.
[0390] The production or activity of a desired nucleic acid gene
product may be increased be increasing the level and/or activity of
a protease that acts upon a protein that that inhibits the
production or function of the nucleic acid gene product. The
production or activity of a desired nucleic acid gene product may
be increased by decreasing the level and/or activity of a protease
that acts upon a protein that stimulates or enhances the production
or function of the desired nucleic acid gene product.
[0391] As one example, manipulation of the alpA gene or gene
product from E. coli (Kirby J. E., and J. E. Trempy, and S.
Gottesman. Excision of a P4-like cryptic prophage leads to Alp
protease expression in Escherichia coli. 1994. J Bacteriol.
176:2068-2081), or homologs of this gene or gene product found in
other members of the Prokaryotes, Eukaryotes or Archaebacteria, may
be employed to increase the efficiency of gene expression and
protein production in parent cells prior to minicell formation
and/or segregated minicells postpartum.
[0392] In addition to alpA, other exemplary E. coli genes and gene
products include the clpA gene and gene product from E. coli
(Katayama Y., and S. Gottesman, and J. Pumphrey, and S. Rudikoff,
and W. P. Clark, and M. R. Maurizi. The two-component,
ATP-dependent Clp protease of Escherichia coli. Purification,
cloning, and mutational analysis of the ATP-binding component.
1988, J Biol Chem. 263-15226-15236); the clpB gene product from E.
coli (Kitagawa M., and C. Wada, and S. Yoshioka, and T. Yura.
Expression of ClpB, an analog of the ATP-dependent proteas
regulatory subunit in Escherichia coli, is controlled by a heat
shock sigma factor (sigma 32). J Bacteriol. 173:4247-4253); the
clpC gene product from E. coli (Msadek T., and F. Kunst, and G.
Rapoport. MecB of Bacillus subtilis, a member of the ClpC ATPase
family, is a pleiotropic regulator controlling competence gene
expression and growth at high temperature. 1994. Proc Natl Acad Sci
USA 91:5788-5792); the clpP gene product from E. coli (Maurizi M.
R., and W. P. Clark, and Y. Katayama, and S. Rudikoff, and J.
Pumphrey, and B. Bowers, and S. Gottesman. Sequence and structure
of ClpP, the proteolytic component of the ATP-dependent Clp
protease of Escherichia coli. 1990. J Biol Chem. 265:12536-12545);
the clpX gene product from E. coli (Gottesman S., and W. P. Clark,
and V. de Crecy-Lagard, and M. R. Maurizi. ClpX, an alternative
subunit for the ATP-dependent Clp protease of Escherichia coli.
Sequence and in vivo activities. 1993. J Biol Chem.
268:22618-22626); the clpY gene product from E. coli (Missiakas D.,
and F. Schwager, J. M. Betton, and C. Georgopoulos, S. Raina.
Identification and characterization of HsIV HsIU (ClpQ ClpY)
proteins involved in overall proteolysis of misfolded proteins in
Escherichia coli. 1996. EMBO J. 15:6899-6909); the dcp gene product
from E. coli (Becker S., and Plapp R. Location of the dcp gene on
the physical map of Escherichia coli. 1992. J Bacteriol.
174:1698-1699); the degP (htrA) gene product from E. coli (Lipinska
B., and M. Zylicz, and C. Georgopoulos. The HtrA (DegP) protein,
essential for Escherichia coli survival at high temperatures, is an
endopeptidase. 1990. J Bacteriol. 172:1791-1797); the ggt gene
product from E. coli (Finidori J., and Y. Laperche, and R.
Haguenauer-Tsapis, and R. Barouki, and G. Guellaen, and J. Hanoune.
In vitro biosynthesis and membrane insertion of gamma-glutamyl
transpeptidase. 1984. J Biol Chem. 259:4687-4690); the hfl gene
product from E. coli (Cheng H. H., and H. Echols. A class of
Escherichia coli proteins controlled by the hflA locus. 1987. J Mol
Biol. 196:737-740); the hflB gene product from E. coli (Banuett F.,
and M. A. Hoyt, and L. McFarlane, and H. Echols, and I. Herskowitz.
HflB, a new Escherichia coli locus regulating lysogeny and the
level of bacteriophage lambda c11 protein. 1986. J Mol Biol.
187:213-224); the hflC gene product from E. coli (Noble J. A., and
M. A. Innis, and E. V. Koonin, and K. E. Rudd, and F. Banuett, and
I. Herskowitz, The Escherichia coli hflA locus encodes a putative
GTP-binding protein and two membrane proteins, one of which
contains a protease-like domain. 1993. Proc Natl Acad Sci U S A.
90:10866-10870); the hflK gene product from E. coli (Id.); the hftX
gene product from E. coli (Noble J. A., and M. A. Innis, and E. V.
Koonin, and K. E. Rudd, and F. Banuett, and I. Hertzskowitz. The
Escherichia coli hflA locus encodes a putative GTP-binding protein
and two membrane proteins, one of which contains a protease-like
domain. 1993. Proc Natl Acad Sci U S A. 90:10866-10870); the hopD
gene product from E. coli (Whitchurch C. B., and J. S. Mattick
Escherichia coli contains a set of genes homologous to those
involved in protein secretion, DNA uptake and the assembly of
type-4 fimbriae in other bacteria. 1994. Gene. 150:9-15); the htrA
gene product from E. coli (Lipinska B., and S. Sharma, and C.
Georgopoulos. Sequence analysis and regulation of the htrA gene of
Escherichia coli: a sigma 32-independent mechanism of
heat-inducible transcription. 1988. Nucleicc Acids Res.
16:10053-10067); the hycI gene product from E. coli (Rossmann R.,
and T. Maier, and F. Lottspeich, and A. Bock. Characterisation of a
proteas from Escherichia coli involved in hydrogenase maturation.
1995. Eur J Biochem. 227:545-550); the iap gene product from E.
coli (Nakata A., and M. Yamaguchi, and K. Isutani, and M. Amemura.
Escherichia coli mutants deficient in the production of alkaline
phosphatase isoszymes. 1978. J Bacteriol. 134:287-294); the lep
gene product from E. coli (Silver P., and W. Wickner. Genetic
mapping of the Escherichia coli leader (signal) peptidase gene
(lep): a new approach for determining the map position of a cloned
gene. 1983. J Bacteriol. 54:659-572); the Ion gene product from E.
coli (Donch J., and J. Greenberg. Genetic analysis of Ion mutants
of strain K-12 of Escherichia coli. 1968. Mol Gen Genet.
103:105-115); the Isp gene product from E. coli (Regue M., and J.
Remenick, and M. tokunaga, and G. A. Mackie, and H. C. Wu. Mapping
of the lipoprotein signal peptidase gene (lsp). 1984. J Bacteriol.
1984 158:632-635); the ompT gene product from E. coli (Akiyama Y.,
and K. SecY protein, a membrane-embedded secretion factor of E.
coli, is cleaved by the ompT proteas in vitro. 1990. Biochem
Biophys Res Commun. 167:711-715); the opdA gene product from E.
coli (Conllin C. A., and C. G. Miller. Location of the prlC (opdA)
gene on the physical map of Escherichia coli. 1993. J Bacteriiol.
175:5731-5732); the orfX gene product from E. coli (Berlyn, M. K.
B., et al. 1996. Linkage map of Escherichia coli K-12, Edition 9.
In F. C. Neidhardt, R. Curtiss, J. L. Ingraham, E. C. C. Lin, K. B.
Low, B. Magasanik, W. S. Reznikoff, M. Riley, M. Schaechter, and H.
E. Umbarger (eds.). Escherichia coli and Salmonella typhimurium:
Cellular and Molecular Biology, 2.sup.nd ed. American Society for
Microbiology, Washington D.C.); the pepA gene product from E. coli
(Stirling C. J., and S. D. Colloms, and J. F. Collins, and G.
Szatmari, and D. J. Sherratt. XerB, an Escherichia coli gene
required for plasmid ColE1 site-specific recombination, is
identical to pepA, encoding aminopeptidaseA, a protein with
substantial similarity to bovine lens leucine aminopeptidase. 1989.
EMBO J. 8:1623-1627); the pepD gene product from E. coli (Henrich
B., and U. Schroeder, and R. W. Frank, and R. Plapp. Accurate
mapping of the Escherichia coli pepD gene by sequence analysis of
its 5' flanking region. 1989. Mol Gen Genet. 215:369-373); the pepE
gene product from E. coli (Conlin C. A., and T. M. Knox, and C. G.
Miller. Cloning and physical map position of an alpha-aspartyl
depeptidase gene, pepE, from Escherichia coli. 1994. J Bacteriol.
176:1552-1553); the pepN gene product from E. coli (Miller C. G.,
and G. Schwartz. Peptidase-deficient mutants of Escherichia coli.
1978. J Bacteriiol. 135:603-611); the pepP gene product from E.
coli (Id.); the pepQ gene product from E. coli (Id.); the pepT gene
product from E. coli (Miller G. G., and G. Schwartz.
Peptidase-deficient mutants of Escherichia coli. 1978. J
Bacteriiol. 135:603-611); the pilD gene product from E. coli
(Francetic O., and S. Lory, and A. P. Pugsley. A second prepilin
peptidase gene in Escherichia coli K-12. 1998, Mol Microbiol.
27:763-775); the pinA gene product from E. coli (Hilliard J. J.,
and L. D. Simon, and L. Van Melderen, and M. R. Maurizi. PinA
inhibits ATP hydrolysis and energy-dependent protein degradation by
Lon protease. 1998. J Biol Chem. 273:524-527); the prc(tsp) gene
product from E. coli (Nagasawa H., and Y. Sakagami, and A. Suzuki,
and H. Suzuki, and H. Hara, and Y. Hirota. Determination of the
cleavage site involved in C-terminal processing of
penicillin-binding proein 3 of Escherichia coli. 1989. J Bacteriol.
171:5890-5893); the prlC gene product from E. coli (Jiang X., and
M. Zhang, and Y. Ding, and J. Yao, and H. Chen, and D. Zhu, and M.
Muramatu. Escherichia coli prlC gene encodes a trypsin-like
proteinase regulating the cell cycle. 1998. J Biochem (Tokyo)
128:980-985); the protease V gene product from E. coli (Berlyn, M.
K. B. et al. 1996. Linkage map of Escherichia coli K-12, Edition 9,
In F. C. Neidhardt, R. Curtiss, J. L. Ingraham, E. C. C. Lin, K. B.
Low, B. Magasanik, W. S. Reznikoff, M. Riley, M. Schaechter, and H.
E. Umbarger (eds.). Escherichia coli and Salmonella typhimurium:
Cellular and Molecular Biology, 2.sup.nd ed. American Society for
Microbiology, Washington, D.C.); the protease VI gene product from
E. coli (Id.); the protease In gene product from E. coli (Id.); the
protease Fa gene product from E. coli or homologues (Id.); the
protease Mi gene product from E. coli (Id.); the protease So gene
product from E. coli (Id.); the ptrA gene product from E. coli
(Id.); the ptrB gene product from E. coli (Id.); the sypB gene
product from E. coli (Barends S., and A. W. Karzai, and R. T.
Sauer, and J. Wower, and B. Kraal. Simultaneous an functional
binding of SmpB and EF-Tu-TP to the analyl acceptor arm of tmRNA.
2001. J Mol Biol. 314:9-21); the sohB gene product from E. coli
(Baird L., and B. Lipinska, and S. Raina, and C. Georgopoulos.
Identification of the Escherichia coli sohB gene, a multicopy
suppressor of the HtrA (DegP) null phenotype. 1991. J Bacteriol.
173-5763-5770); the sspA gene product from E. coli (Ichihara S.,
and T. Suzuki, and M. Suzuki, and C. Mizushima. Molecular cloning
and sequencing of the sppA gene and characterization of the encoded
proteas IV, a signal peptide peptidase of Escherichia coli. 1986. J
Biol Chem. 261;9405-941 1); the tesA gene product from E. coli (Cho
H., and J. E. Cronan Jr. Escherichia coli thioesterase I, molecular
cloning and sequencing of the structural gene and identification as
a periplasmic enzyme. 1993 J Biol Chem. 268:9238-9245); the tufA
gene product from E. coli (Ang., and J. S. Lee, and J. D. Friesen.
Evidence for an internal promoter preceding tufA in the str operon
of Escherichia coli. J Bacteriol. 149:548-553); the tufB gene
product from E. coli (Mihajima A., and M. Shibuya, and Y. Kaziro.
Construction and characterization of the two hybrid Col1E1 plasmids
carrying Escherichia coli tufB gene. 1979. FEBS Lett. 102:207-210);
the ybaU gene product from E. coli (Berlyn, M. K. B., et al. 1996.
Linkage map of Escherichia coli K-12, Edition 9. In F. C.
Neidhardt, R. Curtiss, J. L. Ingraham, E. C. C. Lin, K. B. Low, B.
Magasanik, W. S. Resnikoff, M. Riley, M. Schaechter, and H. E.
Umbarger (eds.). Escherichia coli and Salmonella typhimurium:
Cellular and Molecular Biology, 2.sup.nd ed. American Society for
Microbiology, Washington, D.C.); the ssrA gene (tmRNA, 10 sA RNA)
product from E. coli (Oh B. K., and A. K. Chauhan, and K. Isono,
and D. Apirion. Location of a gene (ssrA) for a small, stable RNA
910Sa RNA) in the Escherichia coli chromosome. 1990. J Bacteriol.
172:4708-4709); and the ssrB gene from E. coli (Berlyn, M. K. B.,
et al. 1996. Linkage map of Escherichia coli K-12, Edition 9. In F.
C. Neidhardt, R. Curtiss, J. L. Ingraham, E. C. C. Lin, K. B. Low,
B. Magasanik, W. S. Reznikoff, M. Riley, M. Schaechter, and H. E.
Ummbarger 9eds.). Escherichia coli and Salmonella typhimurium:
Cellular and Molecular Biology, 2.sup.nd ed. American Society for
Microbiology, Washington, D.C.).
[0393] II. C.13. Chaperones
[0394] Included in the design of the invention are techniques that
increase the efficiency of gene expression and functional protein
production in minicells. By way of non-limiting example, these
techniques may include modification of chaperones and chaperonins,
i.e., endogenous and/or exogenous protein components that monitor
the unfolded state of translated proteins allowing proper folding
and/or secretion, membrane insertion, or soluble multimeric
assembly of expressed proteins in the parental cell prior to
minicell formation and/or the segregated minicell cytoplasm,
membrane, periplasm, and/or extracellular environment. See
Gottesman et al., Protein folding and unfolding by Escherichia coli
chaperones and chaperonins, Current Op. Microbiol. 3:197-202, 2000;
and Mayhew et al., "Molecular Chaperone Proteins," Chapter 61 in:
Escherichia coli and Salmonella typhimurium: Cellular and Molecular
Biology, 2nd Ed., Neidhardt, Frederick C., Editor in Chief,
American Society for Microbiology, Washington, D.C., 1996, Volume
1, pages 922-937, and references cited therein.
[0395] These applications may, but are not limited to increased or
decreased chaperone production, increased or decreased
intramolecular activity of a chaperone, increased or decreased
physiological function of a chaperone, or deletion, substitution,
inversion, translocation or insertion into, or mutation of, a gene
encoding a chaperone. By way of non-limiting example, increased
production of a chaperone may occur through increased chaperone
gene dosage (increased copy number of a given gene under the
control of the native or artificial promotor where this gene may be
on a plasmid or in more than one copy on the chromosome),
modification of the native regulatory elements, including, but not
limited to the promotor or operator region(s) of DNA, or ribosomal
binding sites on RNA, relevant repressors/silencers, relevant
activators/enhancers, or relevant antisense nucleic acid or nucleic
acid analog, cloning on a plasmid under the control of the native
or artificial promotor, and increased or decreased production of
native or artificial promotor regulatory element(s) controlling
production of the chaperone gene or gene product. By way of
non-limiting example, decreased production of a chaperone may occur
through modification of the native regulatory elements, including,
but not limited to the promotor or operator region(s) of DNA, or
ribosomal binding sites on RNA, relevant repressors/silencers,
relevant activators/enhancers, or relevant antisense nucleic acid
or nucleic acid analog, through cloning on a plasmid under the
control of the native regulatory region containing mutations or an
artificial promotor, either or both of which resulting in decreased
chaperone production, and through increased or decreased production
of native or artificial promotor regulatory element(s) controlling
production of the chaperone gene or gene product. By definition,
intramolecular activity refers to the enzymatic function,
structure-dependent function, e.g. the capacity of chaperone to
interact in a protein-protein, protein-nucleic acid, or
protein-lipid complex, and/or carrier function, e.g. the capacity
to bind, either covalently or non-covalently small organic or
inorganic molecules, protein(s), carbohydrate(s), fatty acid(s),
lipid(s), and nucleic acid(s). By way of non-limiting example,
alteration of intramolecular activity may be accomplished by
mutation of the chaperone gene, in vivo or in vitro chemical
modification of Chaperone, inhibitor molecules against the function
of chaperone, e.g. competitive, non-competitive, or uncompetitive
enzymatic inhibitors, inhibitors that prevent protein-protein,
protein-nucleic acid, or protein-lipid interactions, e.g.
expression or introduction of dominant-negative or
dominant-positive chaperone or other protein fragment(s), or other
carbohydrate(s), fatty acid(s), lipid(s), and nucleic acid(s) that
may act directly or allosterically upon Chaperone, and/or
modification of protein, carbohydrate, fatty acid, lipid, or
nucleic acid moieties that modify the chaperone gene or gene
product to create the functional protein. By definition,
physiological function refers to the effects resulting from an
intramolecular interaction between Chaperone and other protein,
carbohydrate, fatty acid, lipid, nucleic acid, or other molecule(s)
in or on the cell or the action of a product or products resulting
from such an interaction. By way of non-limiting example,
physiological function may be the act or result of intermolecular
phosphorylation, biotinylation, methylation, acylation,
glycosylation, and/or other signaling event; this function may be
the result of a protein-protein, protein-nucleic acid, or
protein-lipid interaction resulting in a functional moiety; this
function may be to interact with the membrane to recruit other
molecules to this compartment of the cell; this function may be to
regulate the transcription and/or translation of chaperone, other
protein, or nucleic acid; and this function may be to stimulate the
function of another process that is not yet described or
understood.
[0396] By way of non-limiting example, chaperone genes may be any
of the E. coli genes listed below, as well as any homologs thereof
from prokaryotes, exukariutes, arcahebacteria, or organelles
(mitochondria, chloroplasts, plastids, etc.). Exemplary E. coli
genes encoding chaperones include, by way of non-limiting example,
the cbpA gene (Shiozawa T., and C. Ueguchi, and T. Mizuno. The rpoD
gene functions as a multicopy suppressor for mutations in the
chaperones, CbpA, DnaJ and DnaK, in Escherichia coli. 1996 FEMS
Microbiol Lett. 138:245-250): the clpB gene (Squires C. L., and S.
Pedersen, and B. M. Ross, and C. Squires. ClpB is the Escherichia
coli heat shock protein F84.1. 1991. J Bacteriol. 173:4254-4262);
the dnaK gene (Kroczynska B., and S. Y. Blond. Cloning and
characterization of a new soluble murine J-domain protein that
stimulates BiP, Hsc70 and DnaK ATPase activity with different
efficiencies. 2001. Gene. 273:267-274); the dnaJ gene (Kedzierska
S., and E. Matuszewska. The effect of co-overproduction of
DnaK/DnaJ/GrpE and ClpB proteins on the removal of heat-aggregated
proteins from Escherichia coli Delta clpB mutant cells--new insight
into the role of Hsp70 in a functional cooperation with Hsp100.
2001. FEMS Microbiol Lett. 204:355-360); the ecpD gene (Raina S.,
and D. Missiakas, and L. Baird, and S. Kumar, and C. Georgopoulos.
Identification and transcriptional analysis of the Escherichia coli
htrE operon which is homologous to pap and related pilin operons.
1993. J Bacteriol. 175:5009-5021); the ffh gene (Muller, M., et al.
1002. Protein traffic in bacteria: multiple routes from the
ribosome to and across the membrane. Prog. Nucleic Acid Res. Mol.
Biol. 66:107-157); 4.5S RNA (Muller, M., et al. 1002. Protein
traffic in bacteria: multiple routes from the ribosome to and
across the membrane. Prog. Nucleic Acid Res. Mol. Biol.
66:107-157); the FtsY gene (Muller, M., et al. 1002. Protein
traffic in bacteria: multiple routes from the ribosome to and
across the membrane. Prog. Nucleic Acid Res. Mol. Biol.
66:107-157); the fimC gene (Klemm P., and B. J. Jorgensen, and I.
van Die, and H. de Ree, and H. Bergmans. The fim genes responsible
for synthesis of type 1 fimbriae in Escherichia coli, cloning and
genetic organization. 1985. Mol Gen Genet. 199:410-414); the groE
gene (Burton Z. F., and D. Eisenberg. A procedure for rapid
isolation of both groE protein and glutamine synthetase from E
coli. 1980. Arch Biochem Biophys. 205:478-488); the groL gene
(Berlyn, M. K. B., et al. 1996. Linkage map of Escherichia coli
K-12, Edition 9. In F. C. Neidhardt, R. Curtiss, J. L. Ingraham, E.
C. C. Lin, K. B. Low, B. Magasanik, W. S. Reznikoff, M. Riley, M.
Schaechter, and H. E. Umbarger (eds.). Escherichia coli and
Salmonella typhimurium: cellular and molecular biology, 2nd ed.
American Society for Microbiology, Washington D.C.); the groS gene
(Berlyn, M. K. B., et al. 1996. Linkage map of Escherichia coli
K-12, Edition 9. In F. C. Neidhardt, R. Curtiss, J. L. Ingraham, E.
C. C. Lin, K. B. Low, B. Magasanik, W. S. Reznikoff, M. Riley, M.
Schaechter, and H. E. Umbarger (eds.). Escherichia coli and
Salmonella typhimurium: cellular and molecular biology, 2nd ed.
American Society for Microbiology, Washington D.C.); the hptG gene
(Berlyn, M. K. B., et al. 1996. Linkage map of Escherichia coli
K-12, Edition 9. In F. C. Neidhardt, R. Curtiss, J. L. Ingraham, E.
C. C. Lin, K. B. Low, B. Magasanik, W. S. Reznikoff, M. Riley, M.
Schaechter, and H. E. Umbarger (eds.). Escherichia coli and
Salmonella typhimurium: cellular and molecular biology, 2nd ed.
American Society for Microbiology, Washington D.C.); the hscA gene
(Takahashi Y., and M. Nakamura. Functional assignment of the
ORF2-iscS-iscU-iscA-hscB-hs- cA-fdx-ORF3 gene cluster involved in
the assembly of Fe-S clusters in Escherichia coli. 1999. J Biochem
(Tokyo). 126:917-926); the ibpA gene (Lund P. A. Microbial
molecular chaperones. 2001. Adv Microb Physiol. 44:93-140); the
papJ gene (Tennent, J. M., et al. 1990. Integrity of Escherichia
coli P pili during biogenesis: properties and role of PapJ. Mol.
Microbiol. 4:747-758); the secB gene (Lecker, S., et al. 1989.
Three pure chaperone proteins of Escherichia coli--SecB, trigger
factor and GroEL--form soluble complexes with precursor proteins in
vitro. EMBO J. 8:2703-2709); and the tig gene (Lecker, S., et al.
1989. Three pure chaperone proteins of Escherichia coli--SecB,
trigger factor and GroEL--form soluble complexes with precursor
proteins in vitro. EMBO J. 8:2703-2709); the secE gene (Muller, M.,
et al. 1002. Protein traffic in bacteria: multiple routes from the
ribosome to and across the membrane. Prog. Nucleic Acid Res. Mol.
Biol. 66:107-157); and the secY gene (Muller, M., et al. 1002.
Protein traffic in bacteria: multiple routes from the ribosome to
and across the membrane. Prog. Nucleic Acid Res. Mol. Biol.
66:107-157).
[0397] II.C. 14. Export Apparatus and Membrane Targeting
[0398] Included in the design of the invention are techniques that
increase the efficiency of gene expression and protein production
in parental cells prior to minicell formation and/or in the
segregated minicells. By way of non-limiting example, these
techniques may include construction of chimeric proteins including,
but not limited to, coupling the expressed protein of interest with
native Eubacterial, Eukaryotic, Archeabacterial or organellar
leader sequences to drive membrane insertion or secretion of the
protein of interest to the periplasm or extracellular environment.
In addition to using native leader sequences, these minicell
expression constructs may also include proteolytic cleavage sites
to remove the leader sequence following insertion into the membrane
or secretion. These proteolytic cleavage sites may be native to the
organism from which the minicell is derived or non-native. In the
latter example, also included in the system are the non-native
protease that recognizes the non-native proteolytic cleavage
site.
[0399] Non-limiting examples of these leader sequences may be the
leader from the STII protein (Voss, T., et al. 1994. Periplasmic
expression of human interferon-alpha 2c in Escherichia coli results
in a correctly folded molecule. Biochem. J. 298:719-725), maltose
binding protein (malE) (Ito, K. 1982. Purification of the precursor
form of maltose-binding protein, a periplasmic protein of
Escherichia coli. J. Biol. Chem. 257:9895-9897), phoA (Jobling, M.
G., et al. 1997. Construction and characterization of versatile
cloning vectors for efficient delivery of native foreign proteins
to the periplasm of Escherichia coli. Plasmid. 38:158-173), lamB
(Wong, E. Y., et al. 1988. Expression of secreted insulin-like
growth factor-1 in Escherichia coli. Gene. 68:193-203), ompA (Loo,
T., et al. 2002. Using secretion to solve a solubility problem:
high-yield expression in Escherichia coli and purification of the
bacterial glycoamidase PNGase F. Protein Expr. Purif. 24:90-98), or
pelB (Molloy, P. E., et al. 1998. Production of soluble
single-chain T-cell receptor fragments in Escherichia coli trxB
mutants. Mol. Immunol. 35:73-81).
[0400] In addition to these leader sequences, mutations in the
cellular export machinery may be employed to increase the
promiscuity of export to display or export sequences with
non-optimized leader sequences. Non-limiting examples of genes that
may be altered to increase export promiscuity are mutations in secY
(prlA4) (Derman, A. I., et al. 1993. A signal sequence is not
required for protein export in prlA mutants of Escherichia coli.
EMBO J. 12:879-888), and secE (Harris, C. R., and T. J. Silhavy.
1999. Mapping an interface of SecY (PrlA) and SecE (PrlG) by using
synthetic phenotypes and in vivo cross-linking. J. Bacteriol.
181:3438-3444).
[0401] II. C. 15. Increasing Stability and Solubility
[0402] Included in the design of the invention are techniques that
increase the efficiency of gene expression and protein production
in parental cells prior to minicell formation and/or in the
segregated minicells. By way of non-limiting example, these
techniques may include construction of chimeric/fusion proteins
including, but not limited to, coupling the expressed protein of
interest with native Eubacterial, Eukaryotic, Archeabacterial or
organellar solublizing sequences. As used herein, "solublizing
sequences" are complete or truncated amino acid sequences that
increase the solubility of the expressed membrane protein of
interest. This increased solubility may be used to increase the
lifetime of the soluble state until proper membrane insertion may
take place. By way of non-limiting example, these soluble chimeric
fusion proteins may be ubiquitin (Power, R. F., et al. 1990. High
level expression of a truncated chicken progesterone receptor in
Escherichia coli. J. Biol. Chem. 265:1419-1424), thioredoxin
(LaVallie, E. R., et al. 1993. A thioredoxin gene fusion expression
system that circumvents inclusion body formation in the E. coli
cytoplasm. Biotechnology (N. Y.) 11:187-193; Kapust, R. B., and D.
S. Waugh. 1999. Escherichia coli maltose-binding protein is
uncommonly effective at promoting the solubility of polypeptides to
which it is fused. Protein Sci. 8:1668-1674), the dsbA gene product
(Winter, J., et al. 2001. Increased production of human proinsulin
in the periplasmic space of Escherichia coli by fusion to DsbA. J.
Biotechnol. 84:175-185), the SPG protein (Murphy, J. P., et al.
1992. Amplified expression and large-scale purification of protein
G'. Bioseparation 3:63-71), the malE gene product (maltose-binding
protein) (Hampe, W., et al. 2000. Engineering of a proteolytically
stable human beta 2-adrenergic receptor/maltose-binding protein
fusion and production of the chimeric protein in Escherichia coli
and baculovirus-infected insect cells. J. Biotechnol. 77:219-234;
Kapust et al., Escherichia coli maltose-binding protein is
uncommonly effective at promoting the solubility of polypeptides to
which it is fused, Protein Sci. 8:1668-1674, 1999),
glutathione-s-transferase (GST); and/or nuclease A (Meeker et al.,
A fusion protein between serum amyloid A and staphylococcal
nuclease--synthesis, purification, and structural studies, Proteins
30:381-387, 1998). In addition to these proteins, Staphylococcal
protein A, beta-galactosidase, S-peptide, myosin heavy chain,
dihydrofolate reductase, T4 p55, growth hormone N terminus, E. coli
Hemolysin A, bacteriophage lambda cII protein, TrpE, and TrpLE
proteins may also be used as fusion proteins to increase protein
expression and/or solubility (Makrides, Stratagies for Achieving
High-Level Expression of Genes in Escherichia coli, Microbiol. Rev.
60:512-538).
III. Preparation of Minicells
[0403] III.A. Parent Cell Mutations
[0404] Although it has been reported that relatively few molecules
of endogenous RNA polymerase segregate into minicells (Shepherd et
al., Cytoplasmic RNA Polymerase in Escherichia coli, J Bacteriol
183:2527-34, 2001), other reports and results indicate that many
RNA Polymerase molecules follow plasmids into minicells (Funnell
and Gagnier, Partition of P1 plasmids in Escherichia cole mukB
chromosomal partition mutants, J Bacteriol 177:2381-6, 1995). In
any event, applicants have discovered that the introduction of an
exogenous RNA polymerase to minicell-producing cells enhances
expression of episomal elements in minicells. Such enhanced
expression may allow for the successful expression of proteins in
minicells, wherein such proteins are expressed poorly or not at all
in unmodified minicells. In order to maximize the amount of RNA
transcription from episomal elements in minicells,
minicell-producing cell lines that express an RNA polymerase
specific for certain episomal expression elements may be used. An
example of an E. coli strain of this type, designated MC-T7, was
created and used as is described in the Examples. Those skilled in
the art will be able to make and use equivalent strains based on
the present disclosure and their knowledge of the art.
[0405] Minicell-producing cells may comprise mutations that augment
preparative steps. For example, lipopolysaccharide (LPS) synthesis
in E. coli includes the lipid A biosynthetic pathway. Four of the
genes in this pathway have now been identified and sequenced, and
three of them are located in a complex operon that also contains
genes involved in DNA and phospholipid synthesis. The rfa gene
cluster, which contains many of the genes for LPS core synthesis,
includes at least 17 genes. The rfb gene cluster encodes protein
involved in O-antigen synthesis, and rfb genes have been sequenced
from a number of serotypes and exhibit the genetic polymorphism
anticipated on the basis of the chemical complexity of the O
antigens. See Schnaitman and Klena, Genetics of lipopolysaccharide
biosynthesis in enteric bacteria, Microbiol. Rev. 57:655-82, 1993.
When present, alone, or in combination, the rfb and oms mutations
cause alterations in the eubacterial membrane that make it more
sensitive to lysozyme and other agents used to process minicells.
Similarly, the rfa (Chen, L., and W. G. Coleman Jr. 1993. Cloning
and characterization of the Escherichia coli K-12 rfa-2 (rfaC)
gene, a gene required for lipopolysaccharide inner core synthesis.
J. Bacteriol. 175:2534-2540), lpcA (Brooke, J. S., and M. A.
Valvano. 1996. Biosynthesis of inner core lipopolysaccharide in
enteric bacteria identification and characterization of a conserved
phosphoheptose isomerase. J. Biol. Chem. 271:3608-3614), and lpcB
(Kadrman, J. L., et al. 1998. Cloning and overexpression of
glycosyltransferases that generate the lipopolysaccharide core of
Rhizobium leguminosarum. J. Biol. Chem. 273:26432-26440) mutations,
when present alone or in combination, cause alterations in
lipopolysaccharides in the outer membrane causing cells to be more
sensitive to lysozyme and agents used to process minicells. In
addition, such mutations can be used to reduce the potential
antigenicity and/or toxicity of minicells.
[0406] III.B. Culturing Conditions
[0407] Included in the design of the invention are the conditions
to grow parental cells from which minicells will be produced.
Non-limiting examples herein are drawn to conditions for growing E.
coli parental cells to produce minicells derived from E. coli
parental cells. Non-limiting examples for growth media may include
rich media, e.g. Luria broth (LB), defined minimal media, e.g. M63
salts with defined carbon, nitrogen, phosphate, magnesium, and
sulfate levels, and complex minimal media, e.g. defined minimal
media with casamino acid supplement. This growth may be performed
in culture tubes, shake flasks (using a standard air incubator, or
modified bioreactor shake flask attachment), or bioreactor. Growth
of parental cells may include supplemented additions to assist
regulation of expression constructs listed in the sections above.
These supplements may include, but are not limited to dextrose,
phosphate, inorganic salts, ribonucleic acids, deoxyribonucleic
acids, buffering agents, thiamine, or other chemical that
stimulates growth, stabilizes growth, serves as an osmo-protectant,
regulates gene expression, and/or applies selective pressure to
mutation, and/or marker selection. These mutations may include an
amino acid or nucleotide auxotrophy, while the selectable marker
may include transposable elements, plasmids, bacteriophage, and/or
auxotrophic or antibiotic resistance marker. Growth conditions may
also require temperature adjustments, carbon alternations, and/or
oxygen-level modifications to stimulate temperature sensitive
mutations found in designed gene products for a given desired
phenotype and optimize culture conditions.
[0408] By way of non-limiting example, production of minicells and
protein production may occur by using either of two general
approaches or any combination of each. First, minicells may be
formed, purified, and then contained expression elements may be
stimulated to produce their encoded gene products. Second, parental
cells, from which the minicells are derived, may be stimulated to
express the protein of interest and segregate minicells
simultaneously. Finally, any timing variable of minicell formation
and protein production may be used to optimize protein and minicell
production to best serve the desired application. The two general
approaches are shown in the sections below.
[0409] III.C. Manipulation of Genetic Expression in Minicell
Production
[0410] Included in the design of the invention are methods that
increase the efficiency, rate and/or level of gene expression and
protein production in parent cells and/or minicells. Such methods
include, but are not limited to, the following.
[0411] By way of non-limiting example, parental cells are grown
overnight in the appropriate media. From this culture, the cells
are subcultured into the same media and monitored for growth. At
the appropriate cell density, the cultures are induced for minicell
production using any of the switching mechanisms discussed in
section II.B. regulating any construct discussed in section II.A.
Non-limiting examples of this minicell-inducing switching mechanism
may be the ileR gene product regulating the production of the hns
minicell-inducing gene product or the melR gene product regulating
the production of the minB minicell-inducing gene product.
Following minicell induction, the culture is allowed to continue
growth until the desired concentration of minicells is obtained. At
this point, the mincells are separated from the parental cells as
described in section II.E. Purified minicells are induced for
protein production by triggering the genetic switching mechanism
that segregated into the minicell upon separation from the parental
cell. By way of non-limiting example, this genetic switching
mechanism may be any of those discussed in section I.B. regulating
the production of any protein of interest. Furthermore, at this
point or during the production of minicells the peripheral gene
expression, production, and assembly machinery discussed in section
II.C. may be triggered to assist in this process. By way of
non-limiting example, the groEL complex may be triggered using the
temperature sensitive lambda cI inducible system from a
co-segregant plasmid to assist in the proper assembly of the
expressed protein of interest.
[0412] III.D. Separation of Minicells From Parent Cells
[0413] A variety of methods are used to separate minicells from
parent cells (i.e., the cells from which the minicells are
produced) in a mixture of parent cells and minicells. In general,
such methods are physical, biochemical and genetic, and can be used
in combination.
[0414] III.D.1.Physical Separation of Minicells from Parent
Cells
[0415] By way of non-limiting example, minicells are separated from
parent cells glass-fiber filtration (Christen et al., Gene
23:195-198, 1983), and differential and zonal centrifugation
(Barker et al., J. Gen. Microbiol. 111:387-396, 1979) ,
size-exclusion chromatography, e.g. gel-filtration, differential
sonication (Reeve, J. N., and N. H. Mendelson. 1973. Pronase
digestion of amino acid binding components on the surface of
Bacillus subtilis cells and minicells. Biochem. Biophys. Res.
Commun. 53:1325-1330), and UV-irradiation (Tankersley, W. G., and
J. M. Woodward. 1973. Induction and isoloation of non-replicative
minicells of Salmonella typhimuium and their use as immunogens in
mice. Bacteriol. Proc. 97).
[0416] Some techniques involve different centrifugation techniques,
e.g., differential and zonal centrifugation. By way of non-limiting
example, minicells may be purified by the double sucrose gradient
purification technique described by Frazer and Curtiss, Curr.
Topics Microbiol. Immunol. 69:1-84, 1975. The first centrifugation
involves differential centrifugation, which separates parent cells
from minicells based on differences in size and/or density. The
percent of sucrose in the gradient (graduated from about 5 to about
20%), Ficol or glycerol is designed to allow only parent cells to
pass through the gradient.
[0417] The supernatant, which is enriched for minicells, is then
separated from the pellet and is spun at a much higher rate (e.g.,
.gtoreq.11,000 g). This pellets the minicells and any parent cells
that did not pellet out in the first spin. The pellet is then
resuspended and layered on a sucrose gradient.
[0418] The band containing minicells is collected, pelleted by
centrifugation, and loaded on another gradient. This procedure is
repeated until the minicell preparation is essentially depleted of
parent cells, or has a concentration of parent cells that is low
enough so as to not interfere with a chosen minicell application or
activity. By way of non-limiting example, buffers and media used in
these gradient and resuspension steps may be LB, defined minimal
media, e.g. M63 salts with defined carbon, nitrogen, phosphate,
magnesium, and sulfate levels, complex minimal media, e.g. defined
minimal media with casamino acid supplement, and/or other buffer or
media that serves as an osmo-protectant, stabilizing agent, and/or
energy source, or may contain agents that limit the growth of
contaminating parental cells, e.g. azide, antibiotic, or lack an
auxotrophic supplemental requirement, e.g. thiamine.
[0419] Other physical methods may also be used to remove parent
cells from minicell preparations. By way of non-limiting example,
mixtures of parent cells and minicells are frozen to -20.degree. C.
and then thawed slowly (Frazer and Curtiss, Curr. Topics Microbiol.
Immunol. 69:1-84, 1975).
[0420] III.D.2.Biochemical Separation of Minicells From Parent
Cells
[0421] Contaminating parental cells may be eliminated from minicell
preparations by incubation in the presence of an agent, or under a
set of conditions, that selectively kills dividing cells. Because
minicells can neither grow nor divide, they are resistant to such
treatments.
[0422] Examples of biochemical conditions that prevent or kill
dividing parental cells is treatment with a antibacterial agent,
such as penicillin or derivatives of penicillin. Penicillin has two
potential affects. First, penicillin prevent cell wall formation
and leads to lysis of dividing cells. Second, prior to lysis
dividing cells form filaments that may assist in the physical
separation steps described in section III.E.1. In addition to
penicillin and its derivatives, other agents may be used to prevent
division of parental cells. Such agents may include azide. Azide is
a reversible inhibitor of electron transport, and thus prevents
cell division. As another example, D-cycloserine or phage MS2 lysis
protein may also serve as a biochemical approach to eliminate or
inhibit-dividing parental cells. (Markiewicz et al., FEMS
Microbiol. Lett. 70:119-123, 1992). Khachatourians (U.S. Pat. No.
4,311,797) states that it may be desirable to incubate
minicell/parent cell mixtures in brain heart infusion broth at
36.degree. C. to 38.degree. C. prior to the addition of penicillin
G and further incubations.
[0423] III.D.3.Genetic Separation of Minicells From Parent
Cells
[0424] Alternatively or additionally, various techniques may be
used to selectively kill, preferably lyse, parent cells. For
example, although minicells can internally retain M13 phage in the
plasmid stage of the M13 life cycle, they are refractory to
infection and lysis by M13 phage (Staudenbauer et al., Mol. Gen.
Genet. 138:203-212, 1975). In contrast, parent cells are infected
and lysed by M13 and are thus are selectively removed from a
mixture comprising parent cells and minicells. A mixture comprising
parent cells and minicells is treated with M13 phage at an M.O.I.=5
(phage:cells). The infection is allowed to continue to a point
where .gtoreq.50% of the parent cells are lysed, preferably
.gtoreq.75%, more preferably .gtoreq.95% most preferably
.gtoreq.99%; and .ltoreq.25% of the minicells are lysed or killed,
preferably .ltoreq.15%, most preferably .ltoreq.1%.
[0425] As another non-limiting example of a method by which parent
cells can be selectively killed, and preferably lysed, a chromosome
of a parent cell may include a conditionally lethal gene. The
induction of the chromosomal lethal gene will result in the
destruction of parent cells, but will not affect minicells as they
lack the chromosome harboring the conditionally lethal gene. As one
example, a parent cell may contain a chromosomal integrated
bacteriophage comprising a conditionally lethal gene. One example
of such a bacteriophage is an integrated lambda phage that has a
temperature sensitive repressor gene (e.g., lambda cI857).
Induction of this phage, which-results in the destruction of the
parent cells but not of the achromosomal minicells, is achieved by
simply raising the temperature of the growth media. A preferred
bacteriophage to be used in this method is one that kills and/or
lyses the parent cells but does not produce infective particles.
One non-limiting example of this type of phage is one that lyses a
cell but which has been engineered to as to not produce capsid
proteins that are surround and protect phage DNA in infective
particles. That is, capsid proteins are required for the production
of infective particles.
[0426] As another non-limiting example of a method by which parent
cells can be selectively killed or lysed, toxic proteins may be
expressed that lead to parental cell lysis. By way of non-limiting
example, these inducible constructs may employ a system described
in section II.B. to control the expression of a phage holing gene.
Holin genes fall with in at least 35 different families with no
detectable orthologous relationships (Grundling, A., et al. 2001.
Holins kill without warning. Proc. Natl. Acad. Sci. 98:9348-9352)
of which each and any may be used to lyse parental cells to improve
the purity of minicell preparations.
[0427] Gram negative eubacterial cells and minicells are bounded by
an inner membrane, which is surrounded by a cell wall, wherein the
cell wall is itself enclosed within an outer membrane. That is,
proceeding from the external environment to the cytoplasm of a
minicell, a molecule first encounters the outer membrane (OM), then
the cell wall and finally, the inner membrane (IM). In different
aspects of the invention, it is preferred to disrupt or degrade the
OM, cell wall or IM of a eubacterial minicell. Such treatments are
used, by way of non-limiting example, in order to increase or
decrease the immunogenicity, and/or to alter the permeability
characteristics, of a minicell.
[0428] Eubacterial cells and minicells with altered membranes
and/or cell walls are called "poroplasts.TM." "spheroplasts," and
"protoplasts." Herein, the terms "spheroplast" and "protoplast"
refer to spheroplasts and protoplasts prepared from minicells. In
contrast, "cellular spheroplasts" and "cellular protoplasts" refer
to spheroplasts and protoplasts prepared from cells. Also, as used
herein, the term "minicell" encompasses not only minicells per se
but also encompasses poroplasts.TM., spheroplasts and
protoplasts.
[0429] In a poroplast, the eubacterial outer membrane (OM) and LPS
have been removed. In a spheroplast, portions of a disrupted
eubacterial OM and/or disrupted cell wall either may remain
associated with the inner membrane of the minicell, but the
membrane and cell wall is nonetheless porous because the
permeability of the disrupted OM and cell wall has been increased.
A membrane is said to be "disrupted" when the membrane's structure
has been treated with an agent, or incubated under conditions, that
leads to the partial degradation of the membrane, thereby
increasing the permeability thereof. In contrast, a membrane that
has been "degraded" is essentially, for the applicable intents and
purposes, removed. In preferred embodiments, irrespective of the
condition of the OM and cell wall, the eubacterial inner membrane
is not disrupted, and membrane proteins displayed on the inner
membrane are accessible to compounds that are brought into contact
with the minicell, poroplast, spheroplast, protoplast or cellular
poroplast, as the case may be.
[0430] III.E.2. Poroplasts.TM.
[0431] For various applications poroplasted minicells are capable
of preserving the cytoplasmic integrity while producing increased
stability over that of naked protoplasts. Maintenance of the cell
wall in poroplasted minicells increases the osmotic resistance,
mechanical resistance and storage capacity over protoplasts while
permitting passage of small and medium size proteins and molecules
through the porous cell wall. A poroplast is a Gram negative
bacterium that has its outer membrane only removed. The production
of poroplasts involves a modification of the procedure to make
protoplasts to remove the outer membrane (Birdsell et al.,
Production and ultrastructure of lysozyme and
ethylenediaminetetraacetate-Lysozyme Spheroplasts of Escherichia
coli, J. Bacteriology 93: 427-437, 1967; Weiss, Protoplast
formation in Escherichia coli. J. Bacteriol. 128:668-670, 1976).
Like protoplasts, measuring the total LPS that remains in the
poroplast preparation may be used to monitor the removal of the
outer membrane. Endotoxin kits and antibodies reactive against LPS
may be used to measure LPS in solution; increasing amounts of
soluble LPS indicates decreased retention of LPS by protoplants.
This assay thus makes it possible to quantify the percent removal
of total outer membrane from the poroplasted minicells.
[0432] Several chemical and physical techniques have been employed
to remove the outer membrane of gram negative bacteria. Chemical
techniques include the use of EDTA in Tris to make cells
susceptible to hydrophobic agents such as actinomycin C. Leive L.
The barrier function of the gram-negative envelope. Ann N Y Acad
Sci. 1974 May 10;235(0):109-29.; Voll M J, Leive L. Actinomycin
resistance and actinomycin excretion in a mutant of Escherichia
coli. J Bacteriol. 1970 May;102(2):600-2; Lactic Acid disruption of
the outer membrane as measured by the uptake of hydrophobic
flourophores; Alakomi H L, Skytta E, Saarela M, Mattila-Sandholm T,
Latva-Kala K, Helander I M. Lactic acid permeabilizes gram-negative
bacteria by disrupting the outer membrane. Appl Environ Microbiol.
2000 May;66(5):2001-5; and Polymyxin B disruption as measured by
periplasmic constituent release (Teuber M, Cerny G. Release of the
periplasmic ribonuclease I into the medium from Escherichia coli
treated with the membrane-active polypeptide antibiotic polymyxin
B. FEBS Lett. 1970 May 11;8(1):49-51). Physical techniques include
the use of osmodifferentiation to facilitate the disruption of the
OM. Neu H C, Heppel L A. The release of enzymes from Escherichia
coli by osmotic shock and during the formation of spheroplasts. J
Biol Chem. 1965 September;240(9):3685-92. See also Voll M J, Leive
L. Actinomycin resistance and actinomycin excretion in a mutant of
Escherichia coli. J Bacteriol. 1970 May; 102(2):600-2; Fiil A,
Branton D. Changes in the plasma membrane of Escherichia coli
during magnesium starvation. J Bacteriol. 1969 June;98(3): 1320-7;
and Matsuyama S, Fujita Y, Mizushima S. SecD is involved in the
release of translocated secretory proteins from the cytoplasmic
membrane of Escherichia coli. EMBO J. 1993
January;12(1):265-70.
[0433] III.E.3. Spheroplasts
[0434] A spheroplast is a bacterial minicell that has a disrupted
cell wall and/or a disrupted OM. Unlike eubacterial minicells and
poroplasts, which have a cell well and can thus retain their shape
despite changes in osmotic conditions, the absence of an intact
cell wall in spheroplasts means that these minicells do not have a
rigid form.
[0435] III.E.4. Protoplasts
[0436] A protoplast is a bacterium that has its outer membrane and
cell wall removed. The production of protoplasts involves the use
of lysozyme and high salt buffers to remove the outer membrane and
cell wall (Birdsell et al., Production and ultrastructure of
lysozyme and ethylenediaminetetraacetate-Lysozyme Spheroplasts of
Escherichia coli, J. Bacteriology 93: 427-437, 1967; Weiss,
Protoplast formation in Escherichia coli. J. Bacteriol.
128:668-670, 1976). Various commercially available lysozymes can be
used in such protocols. Measuring the total LPS that remains in the
protoplast preparation is used to monitor the removal of the outer
membrane. Endotoxin kits assays can be used to measure LPS in
solution; increasing amounts of soluble LPS indicates decreased
retention of LPS by protoplasts. This assay thus makes it possible
to quantify the percent removal of total outer membrane from the
minicells. Endotoxin assays are commercially available from, e.g.,
BioWhittaker Molecular Applications (Rockland, Me.)
[0437] For minicell applications that utilize bacterial-derived
minicells, it may be necessary to remove the outer membrane of
Gram-negative cells and/or the cell wall of any bacterial-derived
minicell. For Gram-positive bacterial cells, removal of the cell
wall may be easily accomplished using lysozyme. This enzyme
degrades the cell wall allowing easy removal of now soluble cell
wall components from the pelletable protoplasted minicells. In a
more complex system, the cell wall and outer membrane of
Gram-negative cells may be removed by combination treatment with
EDTA and lysozyme using a step-wise approach in the presence of an
osmoprotecting agent (Birdsell, et al. 1967. Production and
ultrastructure of lysozyme and ethylenediaminetetraacetate-lysozyme
spheroplasts of E. coli, J. Bacteriol. 93:427-437; Weiss, 1976.
Protoplast formation in E. coli. J. Bacteriol. 128:668-670). By
non-limitingBy way of non-limiting example, this osmoprotectant may
be sucrose and/or glycerol. It has been found that the
concentration of the osmoprotectant sucrose, the cell wall
digesting enzyme lysozyme, and chelator EDTA can be optimized to
increase the quality of the protoplasts produced. Separation of
either prepared Gram-negative spheroplasts prepared in either
fashion from removed remaining LPS may occur through exposure of
the spheroplast mixture to an anti-LPS antibody. By non-limitingBy
way of non-limiting example, the anti-LPS antibody may be
covalently, or non-covalently attached to magnetic, agarose,
sepharose, sepheracyl, polyacrylamide, and/or sephadex beads.
Following incubation, LPS is removed from the mixture using a
magnet or slow centrifugation resulting in a protoplast-enriched
supernatant.
[0438] Monitoring loss of LPS may occur through dot-blot analysis
of protoplast mixtures or various commercially available endotoxin
kit assays can be used to measure LPS in solution; increasing
amounts of soluble LPS indicates decreased retention of LPS by
protoplasts. This immuno assay may comprise a step of comparing the
signal to a standard curve in order to quantify the percent removal
of total outer membrane from the minicells. Other endotoxin assays,
such as the LAL Systems from BioWhittaker, are commercially
available. LPS removal has been measured by gas chromatography of
fatty acid methyl esters. Alakomi H L, Skytta E, Saarela M,
Mattila-Sandholm T, Latva-Kala K, Helander I M. Lactic acid
permeabilizes gram-negative bacteria by disrupting the outer
membrane. Appl Environ Microbiol. 2000 May;66(5):2001-5.
[0439] In order to reduce, preferably eliminate, in vivo antigenic
potential of minicells or minicell protoplasts, minicell
protoplasts may be treated to remove undesirable surface
components. Minicell protoplasts so treated are referred to as
"denuded minicells" a term that encompasses both spheroplasts and
protoplasts. Denuding minicells or minicell protoplasts is
accomplished by treatment with one or more enzymes or conditions
that selectively or preferentially removes or make less antigenic
externally displayed proteins. As one non-limiting example, the
protease trypsin is used to digest exposed proteins on the surface
of these particles. In this example, the proteolytic activity of
trypsin may be modulated or terminated by the additional of a
soybean trypsin inhibitor. Non-limiting examples of other proteases
that additionally or alternatively may be used include
chymotrypsin, papain, elastase, proteinase K and pepsin. For some
such proteases, it may be necessary to limit the extent of
proteolysis by, e.g., using a suboptimal concentration of protease
or by allowing the reaction to proceed for a suboptimal period of
time. By the term "suboptimal," it is meant that complete digestion
is not achieved under such conditions, even though the reactions
could proceed to completion under other (i.e., optimal)
conditions.
[0440] It is sometimes preferred to use molecular genetic
techniques to create mutant derivatives of exogenous proteins that
(1) are resistant to the proteases or other enzymes used to prepare
minicells and (2) retain the desired biological activity of the
receptor that is desired to be retained, i.e., the ability to bind
one or more ligands of interest.
[0441] It is within the scope of the invention to have two or more
exogenous proteins expressed within and preferentially displayed by
minicells in order to achieve combined, preferable synergistic,
therapeutic compositions. Similarly, two or more therapeutic
minicell compositions are formulated into the same composition, or
are administered during the same therapeutic minicell compositions
(i.e., "cocktail" therapies). In other types of "cocktail" therapy,
one or more therapeutic minicell compositions are combined or
co-administered with one or more other therapeutic agents that are
not minicell compositions such as, e.g., organic compounds,
therapeutic proteins, gene therapy constructs, and the like.III.F.
Minicells from L-form Eubacteria
[0442] L-form bacterial strains may be used to prepare minicells
and are preferred in some embodiments of the invention. L-form
bacterial strains are mutant or variant strains, or eubacteria that
have been subject to certain conditions, that lack an outer
membrane, a cell wall, a periplasmic space and extracellular
proteases. Thus, in L-form Eubacteria, the cytoplasmic membrane is
the only barrier between the cytoplasm and its surrounding
environment. For reviews, see Grichko, V. P., et al. 1999. The
Potential of L-Form Bacteria in Biotechnology, Can. J. Chem.
Engineering 77:973-977; and Gumpert J., et al. 1998 Use of cell
wall-less bacteria (L-forms) for efficient expression and secretion
of heterologous gene products. Curr Opin Biotechnol. 9:506-9.
[0443] Segregation of minicells from L-form eubacterial parent
cells allows for the generation of minicells that are at least
partially deficient in barriers that lie outside of the cytoplasmic
membrane, thus providing direct access to components displayed on
the minicell membrane. Thus, depending on the strains and methods
of preparation used, minicells prepared from L-form eubacterial
parent cells will be similar if not identical to various forms of
poroplasts, spheroplasts and/or protoplasts. Displayed components
that are accessible in L-form minicells include, but are not
limited to, lipids, small molecules, proteins, sugars, nucleic
acids and/or moieties that are covalently or non-covalently
associated with the cytoplasmic membrane or any component
thereof.
[0444] By way of non-limiting example, L-form Eubacteria that can
be used in the methods of the invention include species of
Escherichia, Streptomyces, Proteus, Bacillus, Clostridium,
Pseudomonas, Yersinia, Salmonella, Enterococcus and Erwinia. See
Onoda, T., et al. 1987. Morphology, growth and reversion in a
stable L-form of Escherichia coli K12. J. Gen. Microbiol.
133:527-534; Inanova, E. H., et al. 1997. Effect of Escherichia
coli L-form cytoplasmic membranes on the interaction between
macrophages and Lewis lung carcinoma cells: scanning electron
microscopy. FEMS Immunol. Med. Microbiol. 17:27-36; Onoda, T., et
al. 2000. Effects of calcium and calcium chelators on growth and
morphology of Escherichia coli L-form NC-7. J Bacteriol.
182:1419-1422; Innes, C. M., et al. 2001. Induction, growth and
antibiotic production of Streptomyces viridifaciens L-form
bacteria. J Appl Microbiol. 90:301-308; Ferguson, C. M., et al.
2000. An ELISA for the detection of Bacillus subtilis L-form
bacteria confirms their symbiosis in strawberry. Lett Appl
Microbiol. 31:390-394; Waterhouse R. N., et al. 1994. An
investigation of enumeration and DNA partitioning in Bacillus
subtilis L-form bacteria. J Appl Bacteriol. 77:497-503; Hoischen,
C., et al. 2002. Novel bacterial membrane surface display system
using cell wall-less L-forms of Proteus mirabilis and Escherichia
coli. Appl. Environ. Microbiol. 68:525-531; Rippmann, J. F., et al.
1998. Procaryotic expression of single-chain variable-fragment
(scFv) antibodies: secretion in L-form cells of Proteus mirabilis
leads to active product and overcomes the limitations of
periplasmic expression in Escherichia coli. Appl. Environ.
Microbiol. 64:4862-4869; Mahony, D. E., et al. 1988. Transformation
of Clostridium perfringens L forms with shuttle plasmid DNA. Appl.
Environ. Microbiol. 54:264-267); Kurona, M., et al. 1983.
Intergenus cell fusions between L-form cells of Pseudomonas
aeruginosa and Escherichia coli. Biken. J. 26:103-111; Ivanova, E.,
et al. 2000. Studies of the interactions of immunostimulated
macrophages and Yersinia enterocolitica O:8. Can. J. Microbiol.
46:218-228; Allan, E. J., et al. 1993. Growth and physiological
characteristics of Bacillus subtilis L-forms. J. Appl. Bacteriol.
74:588-594; Allan, E. J. 1991. Induction and cultivation of a
stable L-form of Bacillus subtilis. J. Appl. Bacteriol. 70:339-343;
Nishikawa, F., et al. 1994. Protective capacity of L-form
Salmonella typhimurium against murine typhoid in C3H/HeJ mice.
Microbiol. Immunol. 38:129-137; Kita, E., et al. 1993. Isolation of
a cytotoxin from L-form Salmonella typhimurium. FEMS Microbiol.
Lett. 109:179-184; Jass, J., et al. Growth and adhesion of
Enterococcus faecium L-forms. FEMS Microbiol. Lett. 115:157-162;
and U.S. Pat. No. 6,376,245.
IV. Assaying Minicells
[0445] IV.A. Efficiency of Minicell Production
[0446] The level of minicell production will vary and may be
evaluated using methods described herein. Relatively high levels of
minicell production are generally preferred. Conditions in which
about 40% of cells are achromosomal have been reported (see, e.g.,
Hassan et al., Suppression of initiation defects of chromosome
replication in Bacillus subtilis dnaA and oriC-deleted mutants by
integration of a plasmid replicon into the chromosomes, J Bacteriol
179:2494-502, 1997). Procedures for identifying strains that give
high yields of minicells are known in the art; see, e.g.,
Clark-Curtiss and Curtiss III, Analysis of Recombinant DNA Using
Escherichia coli Minicells, Meth. Enzol. 101:347-362, 1983.
[0447] Minicell production can be assessed by microscopic
examination of late log-phase cultures. The ratio of minicells to
normal cells and the frequency of cells actively producing
minicells are parameters that increase with increasing minicell
production.
[0448] IV.B. Detecting Protein Synthesis in Minicells
[0449] Methods for detecting and assaying protein production are
known in the art. See, e.g., Clark-Curtiss and Curtiss III, Meth
Enzol 101:347-362, 1983. As an exemplary procedure, transformed E.
coli minicell-producing cells are grown in LB broth with the
appropriate antibiotic overnight. The following day the overnight
cultures are diluted 1:50 in fresh media, and grown at 37.degree.
C. to mid-log phase. If it is desired to eliminate whole cells, an
antibiotic that kills growing (whole) cells but not quiescent cells
(minicells) may be used. For example, in the case of cells that are
not ampicillin resistant, ampicillin (100 mg per ml is added), and
incubation is allowed to continue for about 2 more hrs. Cultures
are then centrifuged twice at low speed to pellet most of the large
cells. Minicells are pelleted by spinning 10 min at 10,000 rpm, and
are then resuspended in M63 minimal media supplemented with 0.5%
casamino acids, and 0.5 mM cAMP, or M9 minimal medium supplemented
with 1 mM MgSO.sub.4, 0.1 mM CaCl.sub.2, 0.05% NaCl, 0.2% glucose,
and 1 ng per ml thiamine. Labeled (.sup.35S) methonine is added to
the minicells for about 15 to about 90 minutes, and minicells are
immediately collected afterwards by centrifugation for 10 min at
4.degree. C. and 14,000 rpm. Cells are resuspended in 50 to 100
.mu.g Laemmeli-buffer, and disrupted by boiling and vortexing (2
min for each step). Incorporation of .sup.35S-methionine was
determined by measuring the amount of radioactivity contained in 1
.mu.l of the lysate after precipitation of proteins with
trichloroacetic acid (TCA). Minicell lysates (50,000 to 100,000 cpm
per lane) are subjected to PAGE on, e.g., 10% polyacrylamide gels
in which proteins of known size are also run as molecular weight
standards. Gels are fixed and images there of are generated by,
e.g., autoradiography or any other suitable detection systems.
[0450] IV.C. Evaluating the Therapeutic Potential of Minicells
[0451] Various methods are used at various stages of development of
a therapeutic minicell composition to estimate their therapeutic
potential. As a non-limiting example, the therapeutic potential of
minicells displaying a receptor is examined as follows.
[0452] IV. C.1. Receptors
[0453] The specificity of, rate of association of, rate of
dissociation of, and/or stability of complexes resulting from,
receptor binding to its ligand can be measured in vitro using
methods known in the art.
[0454] In the case of a sphingolipid binding receptor, such as an
SIP receptor, the ligand (SIP) is detectably labeled so that the
specificity of, rate of formation of, and degree of stability of
complexes resulting from the ligand-receptor binding can be
examined by measuring the degree and rate at which the labeled
ligand is removed from solution due to its binding to minicells
displaying the receptor. In order to avoid extraneous factors from
influencing these experiments, they are carried out in buffered
solutions that are as free of contaminating substances as possible.
However, as is understood in the art, stabilizing agents such as
BSA (bovine serum albumin) or protease inhibitors may be desirably
included in these experiments. In a preferred environment, a
sphingolipid binding receptor is the rat EDG-1, rat EDG-3, rat
SCaMPER and human SCaMPER, the sequences of which are set forth
herein.
[0455] Minicell compositions that bind sphingolipids with the
desired specificity are identified from the preceding experiments.
Typically, studies of ligand-receptor binding then proceed to
studies in which the binding capacity of promising minicell
compositions is tested under in vitro conditions that are
increasingly more representative of in vivo conditions. For
example, binding experiments are carried out in the presence of
sera or whole blood in order to determine the therapeutic potential
of minicell compositions in the presence of compounds that are
present within the circulatory system of an animal.
[0456] IV.C.2.Molecular Sponge
[0457] Minicell compositions can also be tested for their ability
to bind and/or interanlize toxic compounds. The therapeutic
potential of such capacity is evaluated using experiments in which
detectably labeled derivatives of a toxic compound are present in
the bloodstream of an anesthetized animal, which may a human. The
blood of the animal is shunted out of the body and past a device
that incorporates a minicell composition before being returned to
the body. The device is constructed so that the blood contacts a
semipermeable membrane that is in contact with the minicell
composition. By "semipermeable" it is meant that certain agents can
be freely exchanged across the membrane, whereas others are
retained on one side of the membrane or the other. For example, the
toxic compound of interest is able to cross the semipermeable
membrane, whereas minicells and blood cells are separately retained
in their respective compartments. Detectably labeled derivatives of
the toxic compound are present in the bloodstream of the animal.
The capacity of the minicells to take up the toxic compound
corresponds with a reduction of the levels of detectably labeled
material in the blood and an increase in detectably labeled
material in the minicell composition.
[0458] The above types of minicell-comprising compositions,
devices, and procedures may be incorporated into ex vivo modalities
such as ex vivo gene therapy and dialysis machines. An "ex vivo
modality" is one in which a biological sample, such as a blood
sample, is temporarily removed from an animal, altered through in
vitro manipulation, and then returned to the body. In "ex vivo gene
therapy," cells in the sample from the animal are transformed with
DNA in vitro and then returned to the body. A "dialysis machine" is
a device in which a fluid such as blood of an animal is temporarily
removed therefrom and processed through one or more physical,
chemical, biochemical, binding or other processes designed to
remove undesirable substances including but are not limited to
toxins, venoms, overexpressed or overactive endogenous agents, and
pathogens or molecules derived therefrom.
[0459] Intraminicellular co-expression of a second molecule that is
displayed on the surface of minicells, and which is a ligand for a
binding moiety that is immobilized, can optionally be used in order
to remove minicells from the sample before it is returned to the
body. In the latter aspect, minicells that bind undesirable
substances are preferably removed with the undesirable compound
remaining bound to the minicells. Minicells that have been used for
ex vivo gene therapy, but which have failed to deliver a nucleic
acid to any cells in the sample, can be removed in a similar
manner.
[0460] IV.C.3.Minicell-Solubilized Receptors
[0461] It is known in the art to use recombinant DNA technology to
prepare soluble (hydrophilic) receptor fragments from receptors
that bind a bioactive ligand. Unlike the native, membrane-bound
receptor, which is relatively insoluble in water (hydrophobic),
soluble receptor fragments can be formulated for therapeutic
delivery using techniques that are known to have been used to
formulate soluble agents.
[0462] Typically, soluble receptor fragments are used to
competitively inhibit the binding of the receptor to its ligand.
That is, the soluble receptor fragments bind the ligand at the
expense of the membrane-bound receptor. Because less of the ligand
is bound to its receptor, the cellular response to the ligand is
attenuated. Common cellular responses that are desirably attenuated
include but are not limited to the uptake of an undesirable agent
(e.g., a toxin, a pathogen, etc.) and activation of a signaling
pathway having undesirable consequences (e.g., inflammation,
apoptosis, unregulated growth, etc.).
[0463] Preparing a soluble fragment derived from a receptor is not
trivial. Typically, the three dimensional structure of the receptor
is not known, and must be predicted based on homology with other
receptors or by using software that predicts the tertiary structure
of a polypeptide based on its amino acid sequence. Using the
hypothetical structure of the receptor, a series of polypeptides
are prepared that comprise amino acid sequences from the receptor
but lack regions thereof that are thought to be membrane-anchoring
or transmembrane domain(s) of the receptor. Some of the
polypeptides prepared this way may be soluble, some may retain the
binding activity of the receptor, and a few may have both
characteristics. Members of the latter class of polypeptides are
soluble receptor fragments, some of which may be amenable to
development as a therapeutic or diagnostic agent.
[0464] For any given receptor, there is always the possibility that
none of the soluble fragments derived from the receptor will
specifically bind its ligand with sufficient affinity as to be
thereapeutically effective. Thus, in some instances, it may not be
possible to prepare a receptor fragment that is both soluble and
sufficiently biologically active.
[0465] The minicells of the invention provide a "universal carrier"
for receptors that allows the hydrophobic receptors to be
solubilized in the sense that, although they remain associated with
a membrane, the minicell is a small, soluble particle. That is, as
an alternative to preparing a set of polypeptides to see which, if
any of them, are water soluble receptor fragments, one may, using
the teachings of the disclosure, prepare soluble minicells that
display the receptor.
[0466] IV.C.4.Reducing Toxicity
[0467] For in vivo use of minicells for the purposes of eliciting
an immune response or for therapeutic and diagnostic applications
involving delivery of minicells to a human or to an anima, it may
be useful to minimize minicell toxicity by using
endotoxin-deficient mutants of parent cells. Without being limited
to the following example, lipopolysaccharide (LPS) deficient E.
coli strains could be conjugated with minicell producing cells to
make parent cells lacking the endotoxin. LPS synthesis in E. coli
includes the lipid A biosynthetic pathway. Four of the genes in
this pathway have now been identified and sequenced, and three of
them are located in a complex operon which also contains genes
involved in DNA and phospholipid synthesis. The rfa gene cluster,
which contains many of the genes for LPS core synthesis, includes
at least 17 genes. The rfb gene cluster encodes protein involved in
O-antigen synthesis, and rfb genes have been sequenced from a
number of serotypes and exhibit the genetic polymorphism
anticipated on the basis of the chemical complexity of the O
antigens (Schnaitman and Klena. 1993. Genetics of
lipopolysaccharide biosynthesis in enteric bacteria. Microbiol.
Rev. 57:655-82). When present alone or in combination the rfb and
oms mutations cause alterations in the eubacterial membrane that
make it more sensitive to lysozyme and other agents used to process
minicells. Similarly, the rfa (Chen, L., and W. G. Coleman Jr.
1993. Cloning and characterization of the Escherichia coli K-12
rfa-2 (rfaC) gene, a gene required for lipopolysaccharide inner
core synthesis. J. Bacteriol. 175:2534-2540), IpcA (Brooke, J. S.,
and M. A. Valvano. 1996. Biosynthesis of inner core
lipopolysaccharide in enteric bacteria identification and
characterization of a conserved phosphoheptose isomerase. J. Biol.
Chem. 271:3608-3614), and IpcB (Kadrman, J. L., et al. 1998.
Cloning and overexpression of glycosyltransferases that generate
the lipopolysaccharide core of Rhizobium leguminosarum. J. Biol.
Chem. 273:26432-26440) mutations, when present alone or in
combination, cause alterations in lipopolysaccharides in the outer
membrane causing cells to be more sensitive to lysozyme and agents
used to process minicells. In addition, such mutations can be used
to reduce the potential antigenicity and/or toxicity of
minicells.
[0468] Minicell-producing cells may comprise mutations that augment
preparative steps. For example, lipopolysaccharide (LPS) synthesis
in E. coli includes the lipid A biosynthetic pathway. Four of the
genes in this pathway have now been identified and sequenced, and
three of them are located in a complex operon that also contains
genes involved in DNA and phospholipid synthesis. The rfa gene
cluster, which contains many of the genes for LPS core synthesis,
includes at least 17 genes. The rfb gene cluster encodes protein
involved in O-antigen synthesis, and rfb genes have been sequenced
from a number of serotypes and exhibit the genetic polymorphism
anticipated on the basis of the chemical complexity of the O
antigens. See Schnaitman and Klena, Genetics of lipopolysaccharide
biosynthesis in enteric bacteria, Microbiol. Rev. 57:655-82, 1993.
When present, alone, or in combination, the rfb and oms mutations
cause alterations in the eubacterial membrane that make it more
sensitive to lysozyme and other agents used to process minicells.
Similarly, the rfa (Chen, L., and W. G. Coleman Jr. 1993. Cloning
and characterization of the Escherichia coli K-12 rfa-2 (rfaC)
gene, a gene required for lipopolysaccharide inner core synthesis.
J. Bacteriol. 175:2534-2540), IpcA (Brooke, J. S., and M. A.
Valvano. 1996. Biosynthesis of inner core lipopolysaccharide in
enteric bacteria identification and characterization of a conserved
phosphoheptose isomerase. J. Biol. Chem. 271:3608-3614), and lpcB
(Kadrman, J. L., et al. 1998. Cloning and overexpression of
glycosyltransferases that generate the lipopolysaccharide core of
Rhizobium leguminosarum. J. Biol. Chem. 273:26432-26440) mutations,
when present alone or in combination, cause alterations in
lipopolysaccharides in the outer membrane causing cells to be more
sensitive to lysozyme and agents used to process minicells. In
addition, such mutations can be used to reduce the potential
antigenicity and/or toxicity of minicells.
V. Genetic Expression in Minicells
[0469] Various minicells of the invention use recombinant DNA
expression systems to produce a non-eubacterial protein, which may
be a membrane protein that is preferably "displayed" on the surface
of minicells, a membrane protein that projects portions not
associated with a membrane towards the interior of a minicell, or a
soluble protein present in the exterior of the minicells. By
"displayed" it is meant that a protein is present on the surface of
a cell (or minicell) and is thus in contact with the external
environment of the cell. Non-limiting examples of displayed
exogenous proteins of the invention include mammalian receptors and
fusion proteins comprising one or more transmembrane domains. In
other aspects of the invention, minicells use expression elements
to produce bioactive nucleic acids from templates therefor.
[0470] V.A. Expression Systems
[0471] In vivo and in vitro protein expression systems provide a
variety of techniques that allow scientists to transcribe and
translate amino acid polypeptides proteins from recombinant DNA
templates (Kaufman, Overview of vector design for mammalian gene
expression. Mol Biotechnol, 2001. 16: 151-160; and Kozak,
Initiation of translation in prokaryotes and eukaryotes. Gene,
1999. 234: 187-208).
[0472] Although minicells are virtually depleted of chromosomal DNA
(Tudor et al., Presence of nuclear bodies in some minicells of
Escherichia coli. J Bacteriol, 1969. 98: 298-299), it has been
reported that minicells have all the elements required to express
nucleotide sequences that are present in episomal expression
elements therein (Levy, Very stable prokaryote messenger RNA in
chromosomeless Escherichia coli minicells. Proc Natl Acad Sci USA,
1975. 72: 2900-2904; Hollenberg et al., Synthesis of high molecular
weight polypeptides in Escherichia coli minicells directed by
cloned Saccharomyces cerevisiae 2-micron DNA. Gene, 1976. 1: 33-47;
Crooks et al., Transcription of plasmid DNA in Escherichia coli
minicells. Plasmid, 1983. 10: 66-72; Clark-Curtiss, Analysis of
recombinant DNA using Escherichia coli minicells. Methods Enzymol,
1983. 101: 347-362).
[0473] Preferred expression vectors and constructs according to the
invention are episomal genetic elements. By "episomal" it is meant
that the expression construct is not always linked to a cell's
chromosome but may instead be retained or maintained in host cells
as a distinct molecule entity. Minicells can retain, maintain and
express episomal expression constructs such as, e.g., plasmids,
bacteriophage, viruses and the like (Crooks et al., Plasmin
10:66-72, 1983; Clark-Curtiss, Methods Enzymology 101:347-62, 1983;
Witkiewicz et al., Acta. Microbiol. Pol. A 7:21-24, 1975; Ponta et
al., Nature 269:440-2, 1977). By "retained" it is meant that the
episomal expression construct is at least temporarily present and
expressed in a host parent cell and/or minicell; by "maintained" it
is meant that the episomal expression construct is capable of
autonomous replication within a host parent cell and/or minicell.
In the context of episomal elements, the term "contained"
encompasses both "retained" and "maintained." A preferred type of
an episomal element according to the invention is one that is
always an extrachromocomal element, or which is part of a
chromosome but becomes an extrachromosomal element before or during
minicell production.
[0474] The fact that minicells do not contain chromosomal DNA but
do contain episomal expression elements, such as plasmids, that can
be used as templates for RNA synthesis means that the only proteins
that are actively produced in minicells are those that are encoded
by the expression elements that they contain. Minicell-producing E.
coli cells can be made competent and transformed with expression
elements that direct the expression of proteins encoded by the
expression elements. An expression element segregates into
minicells as they are produced. In isolated minicells that contain
expression elements, there is a single DNA template RNA for
transcription. Therefore, the only nucleic acids and proteins that
are actively produced (expressed) by minicells are those that are
encoded by sequences on the expression vector. In the context of
the invention, sequences that encode amino acid sequences are
designated "open reading frames" or "ORFs." One feature of minicell
expression systems of interest as regards the present invention is
that endogenous (i.e., chromosomally located) genes are not present
and are thus not expressed, whereas genes present on the episomal
element are expressed (preferably over-expressed) in the minicells.
As a result, the amount of endogenous proteins, including membrane
proteins, decreases as the minicells continue to express genes
located on episomal expression constructs.
[0475] The minicell system can reduce or eliminate undesirable
features associated with the transcription and translation of
endogenous proteins from the E. coli chromosome. For example,
expression of proteins in minicell systems results in low
background signal ("noise") when radiolabeled proteins produced
using recombinant DNA technology (Jannatipour et al., Translocation
of Vibrio Harveyi N,N'-DIacetylchitobiase to the outer membrane of
Escherichia coli. J. Bacteriol, 1987. 169: 3785-3791). A high
background signal can make it difficult to detect a protein of
interest. In whole cell E. coli systems, endogenous proteins
(encoded by the bacterial chromosome) are labeled as well as the
protein(s) encoded by the expression element; whereas, in minicell
systems, only the proteins encoded by the expression element in the
minicells are labeled.
[0476] There are a variety of proteins, both eubacterial and
eukaryotic, that have been expressed from plasmid DNA in minicells
(Clark-Curtiss, Methods Enzymal, 101:347-362, 1983). Some examples
of proteins and nucleic acids that have been expressed in minicells
include the Kdp-ATPase of E. coli (Altendorf et al., Structure and
function of the Kdp-ATPase of Escherichia coli. Acta Physiol Scand,
643: 137-146, 1998); penicillin binding proteins aplha and gamma
(Davies et al., Prediction of signal sequence-dependent protein
translocation in bacteria: Assessment of the Escherichia coli
minicell system. Biochem Biophys Res Commun, 150: 371-375, 1988);
cell surface antigens of Polyromaonas gingivalas (Rigg et al., The
molecular cloning, nucleotide sequence and expression of an
antigenic determinant from Porphyromonas gingivalis. Arch Oral
Biol, 45:41-52, 2000); trkG integral membrane protein of E. coli
(Schlosser et al., Subcloning, Nucleotide sequence, and expression
of trkG, a gene that encodes an integral membrane protein involved
in potassium uptake via the Trk system of Escherichia coli. J.
Bacteriol, 173:3170-3176, 1991); the 34 kDa antigen of Treponema
pallidum (Swancutt et al., Molecular characterization of the
pathogen-specific, 34-kilodalton membrane immunogen of Treponema
pallidum. Infect Immun, 57:3314-23, 1989); late proteins of
bacteriophage MB78 (Colla et al., IUBMB Life 48:493-497, 1999);
uncharacterisized DNA from Xenopus laevis (Cohen and Boyer, U.S.
Pat. No. 4,237,224, which issued Dec. 2, 1980); the onc gene v-fos
(MacConnell and Verman, Expression of FBJ-MSV oncogene (fos)
product in bacteria, 131(2) Virology 367 1983); interferon (Edge et
al., Chemical synthesis of a human inteferon-alpha 2 gene and its
expression in Escherichia coli, Nucleic Acids Res. 11:6419, 1983);
bovine growth hormone (Rosner et al., Expression of a cloned bovine
growth hormone gene in Escherichia coli minicells, Can. J. Biochem.
60:521-4, 1982); gastroitestinal hormone (Suzuki et al., Production
in Escherichia coli of biologically active secretin, a
gastroninstestinal hormone, Proc. Natl. Acad. Sci. USA 79:2475,
1982); and archeabacterial proteins (Lienard and Gottschalk,
Cloning, sequencing and expression of the genes encoding the sodium
translocating N-methyltetrahydromethanopterin: coenzyme M
methyltransferase of the methylotrohic archaeon Methanosarcina
mazei Gol, 425 FEBS Letters 204, 1998; and Lemker et al.,
Overproduction of a functional A1 ATPase from the archaeon
Methanosarcina mazei G1 in Escherichia coli, European Journal of
Biochemistry 268:3744, 2001).
[0477] V.B. Modulating Genetic Expression in Minicells
[0478] Gene expression in minicells, and/or in minicell-producing
(parent) cells, involves the coordinated activity of a variety of
expression factors,regulatory elements and expression sequences.
Any of these may be modified to alter the extent, timing or
regulation of expression of a gene of interest in minicells and/or
their parent cells. Often, the goal of the manipulations is to
increase the efficiency of protein production in minicells.
However, increased expression may, in some instances, desirably
include increased or "tight" negative regulation. This may reduce
or eliminate selective pressure created by toxic gene products, and
allow for functional expression in a controlled fashion by removing
the negative regulation and/or inducing expression of the gene
product at a preselected time. By way of non-limiting example,
these techniques may include modification or deletion of endogenous
gene(s) from which their respective gene product decreases the
induction and expression efficiency of a desired protein in the
parent cell prior to minicell formation and/or the segregated
minicell. By way of non-limiting example, these protein components
may be the enzymes that degrade chemical inducers of expression,
proteins that have a dominant negative affect upon a positive
regulatory elements, proteins that have proteolytic activity
against the protein to be expressed, proteins that have a negative
affect against a chaperone that is required for proper activity of
the expressed protein, and/or this protein may have a positive
effect upon a protein that either degrades or prevents the proper
function of the expressed protein. These gene products that require
deletion or modification for optimal protein expression and/or
function may also be antisense nucleic acids that have a negative
affect upon gene expression.
VI. Fusion (Chimeric) Proteins
[0479] In certain aspects of the invention, a fusion protein is
expressed and displayed by minicells. One class of fusion proteins
of particular interest are those that are displayed on the surface
of minicells, e.g., fusion proteins comprising one or more
transmembrane domains. Types of displayed fusion proteins of
particular interest are, by way of non-limiting example, those that
have an extracellular domain that is a binding moiety or an
enzymatic moiety. By way of non-limiting example, the fusion
protein ToxR-PhoA has been expressed in and displayed on the
surface of minicells. The ToxR-PhoA fusion protein comprises a
polypeptide corresponding to the normally soluble enzyme, alkaline
phosphatase, anchored to the minicell membrane by the single
transmembrane domain of ToxR (see the Examples). The fusion protein
retains the activity of the enzyme in the context of the minicell
membrane in which it is bound. Nearly all of the fusion protein is
oriented so that the enzyme's catalytic domain is displayed on the
outer surface of the minicell.
[0480] VI.A. Generation of Fusion Proteins
[0481] Polypeptides, which are polymers of amino acids, are encoded
by another class of molecules, known as nucleic acids, which are
polymers of structural units known as nucleotides. In particular,
proteins are encoded by nucleic acids known as DNA and RNA
(deoxyribonucleic acid and ribonucleic acid, respectively).
[0482] The nucleotide sequence of a nucleic acid contains the
"blueprints" for a protein. Nucleic acids are polymers of
nucleotides, four types of which are present in a given nucleic
acid. The nucleotides in DNA are adenine, cytosine and guanine and
thymine, (represented by A, C, G, and T respectively); in RNA,
thymine (T) is replaced by uracil (U). The structures of nucleic
acids are represented by the sequence of its nucleotides arranged
in a 5' ("5 prime") to 3' ("3 prime") direction, e.g.,
5'-A-T-G-C-C-T-A-A-A-G-C-C-G-C-T-C-C-C-T-C-A-3'
[0483] In biological systems, proteins are typically produced in
the following manner. A DNA molecule that has a nucleotide sequence
that encodes the amino acid sequence of a protein is used as a
template to guide the production of a messenger RNA (mRNA) that
also encodes the protein; this process is known as transcription.
In a subsequent process called translation, the mRNA is "read" and
directs the synthesis of a protein having a particular amino acid
sequence.
[0484] Each amino acid in a protein is encoded by a series of three
contiguous nucleotides, each of which is known as a codon. In the
"genetic code," some amino acids are encoded by several codons,
each codon having a different sequence; whereas other amino acids
are encoded by only one codon sequence. An entire protein (i.e., a
complete amino acid sequence) is encoded by a nucleic acid sequence
called a reading frame. A reading frame is a continuous nucleotide
sequence that encodes the amino acid sequence of a protein; the
boundaries of a reading frame are defined by its initiation (start)
and termination (stop) codons.
[0485] The process by which a protein is produced from a nucleic
acid can be diagrammed as follows: 1
[0486] A chimeric reading frame encoding a fusion protein is
prepared as follows. A "chimeric reading frame" is a genetically
engineered reading frame that results from the fusion of two or
more normally distinct reading frames, or fragments thereof, each
of which normally encodes a separate polypeptide. Using recombinant
DNA techniques, a first reading frame that encodes a first amino
acid sequence is linked to a second reading frame that encodes a
second amino acid sequence in order to generate a chimeric reading
frame. Chimeric reading frames may also include nucleotide
sequences that encode optional fusion protein elements (see
below).
[0487] A hypothetical example of a chimeric reading frame created
from two normally separate reading frames is depicted in the
following flowchart.
First Open Reading Frame and "Protein-1"
[0488] 2
Second Open Reading Frame and "Protein-2"
[0489] 3
Chimeric Reading Frame that encodes a Fusion Protein having
sequences from Protein-i and Protein-2
[0490] 4
[0491] In order for a chimeric reading frame to be functional, each
normally distinct reading frame therein must be fused to all of the
other normally distinct reading frames in a manner such that all of
the reading frames are in frame with each other. By "in frame with
each other" it is meant that, in a chimeric reading frame, a first
nucleic acid having a first reading frame is covalently linked to a
second nucleic acid having a second reading frame in such a manner
that the two reading frames are "read"(translated) in register with
each other. As a result, the chimeric reading frame encodes one
extended amino acid sequence that includes the amino acid sequences
encoded by each of the normally separate reading frames. A fusion
protein is thus encoded by a chimeric reading frame.
[0492] The fusion proteins of the invention are used to display
polypeptides on minicells. The fusion proteins comprise (1) at
least one polypeptide that is desired to be displayed by minicells
(a "displayed polypeptide") and (2) at least one membrane
polypeptide, e.g., a transmembrane or a membrane anchoring domain.
For various aspects of the invention, optional fusion protein
elements, as defined herein, may also be included if required or
desired.
[0493] VI.B. Optional Fusion Protein Elements
[0494] The fusion proteins of the invention may optionally comprise
one or more non-biologically active amino acid sequences, i.e.,
optional fusion protein elements. Such elements include, but are
not limited to, the following optional fusion protein elements. It
is understood that a chimeric reading frame will include nucleotide
sequences that encode such optional fusion protein elements, and
that these nucleotide sequences will be positioned so as to be in
frame with the reading frame encoding the fusion protein. Optional
fusion protein elements may be inserted between the displayed
polypeptide and the membrane polypeptide, upstream or downstream
(amino proximal and carboxy proximal, respectively) of these and
other elements, or within the displayed polypeptide and the
membrane polypeptide. A person skilled in the art will be able to
determine which optional element(s) should be included in a fusion
protein of the invention, and in what order, based on the desired
method of production or intended use of the fusion protein.
[0495] Detectable polypeptides are optional fusion protein elements
that either generate a detectable signal or are specifically
recognized by a detectably labeled agent. An example of the former
class of detectable polypeptide is green fluorescent protein (GFP).
Examples of the latter class include epitopes such as a "His tag"
(6 contiguous His residues, a.k.a. 6.times.His), the "FLAG tag" and
the c-myc epitope. These and other epitopes can be detected using
labeled antibodies that are specific for the epitope. Several such
antibodies are commercially available.
[0496] Attachment (support-binding) elements are optionally
included in fusion proteins and can be used to attach minicells
displaying a fusion protein to a preselected surface or support.
Examples of such elements include a "His tag," which binds to
surfaces that have been coated with nickel; streptavidin or avidin,
which bind to surfaces that have been coated with biotin or
"biotinylated" (see U.S. Pat. No. 4,839,293 and Airenne et al.,
Protein Expr. Purif. 17:139-145, 1999); and
glutathione-s-transferase (GST), which binds to surfaces coated
with glutathione (Kaplan et al., Protein Sci. 6:399-406, 1997; U.S.
Pat. 5,654,176). Polypeptides that bind to lead ions have also been
described (U.S. Pat. No. 6,111,079).
[0497] Spacers (a.k.a. linkers) are amino acid sequences that are
optionally included in a fusion protein in between other portions
of a fusion protein (e.g., between the membrane polypeptide and the
displayed polypeptide, or between an optional fusion protein
element and the remainder of the fusion protein). Spacers can be
included for a variety of reasons. For example, a spacer can
provide some physical separation between two parts of a protein
that might otherwise interfere with each other via, e.g., steric
hindrance. The ability to manipulate the distance between the
membrane polypeptide and the displayed polypeptide allows one to
extend the displayed polypeptide to various distances from the
surface of minicells.
[0498] VI.C. Interactions with Receipient Cells
[0499] Many Gram-negative pathogens use a type III secretion
machine to translocate protein toxins across the bacterial cell
envelope (for a review, see Cheng L W, Schneewind O. Type III
machines of Gram-negative bacteria: delivering the goods. Trends
Microbiol 2000 May;8(5):214-20). For example, pathogenic Yersinia
spp. export over a dozen Yop proteins via a type III mechanism,
which recognizes secretion substrates by signals encoded in yop
mRNA or chaperones bound to unfolded Yop proteins. A 70-kb
virulence plasmid found in pathogenic Yersinia spp. to survive and
multiply in the lymphoid tissues of the host. The virulence plasmid
encodes the Yop virulon, an integrated system allowing
extracellular bacteria to inject bacterial proteins into cells. The
Yop virulon comprises a variety of Yop proteins and a dedicated
type III secretion apparatus, called Ysc (for a review, see
Cornelis G R, Boland A, Boyd A P, Geuijen C, Iriarte M, Neyt C,
Sory M P, Stainier I. The virulence plasmid of Yersinia, an
antihost genome. Microbiol Mol Biol Rev 1998 62(4):1315-52).
VII. Minicell Display
[0500] Included in the design of the invention is the use of
minicells to express and display soluble or membrane-bound protein
libraries to identify a soluble or membrane-bound protein that
binds a known ligand or to identify proteins (e.g. orphan
receptors) for which the known ligand or substrate is not known but
for which a reporter could be engineered into the minicell that
would signal the presence of the encoded protein. In the preferred
embodiment of the invention, this minicell display technique is
analogous to phage display for the purpose of identifying genes
that encode receptor-like or antibody-like proteins against known
ligand. This approach will allow identification of an unknown
receptor protein for which a known ligand has affinity. These known
ligands may have been identified as having a pharmacological,
biological, or other effect without knowledge of the site of
effect. In these cases the knowledge of receptor will allow basic
research to understand the molecular and/or physiological response
and permit directed modification of the ligand for better
pharmacological or biological response or modification of the
receptor for employment in ligand-binding applications. In another
non-limiting embodiment of the invention, the ligand need not be
known but some general characteristic of the protein would be.
[0501] For purposes of this application, soluble or membrane-bound
protein libraries may be constructed by random cloning of DNA
fragments or directed cloning using reverse transcriptase
polymerase chain reaction (RT-PCR). In either method, DNA fragments
may be placed under the regulation of any regulatory element listed
in section II.B. on any plasmid or chromosomal construct. In the
case of soluble protein receptors, they will be fused to form a
chimeric protein with a known transmembrane domain (TMD), e.g. the
TMD from the toxR gene product. Upon induction of the soluble or
membrane-bound protein library, minicells, minicell protoplasts, or
minicell poroplasts (as the experiment requires) will be mixed with
the known ligand. Without being limited to the following example,
screening could be accomplished by first -labeling the known ligand
with a molecular flourophore, e.g. TAMRA, FTC, or in some cases a
fluorescent protein, e.g. GFP. A positive interaction between the
minicells displaying the receptor for the labeled ligand will be
identified and separated from the library population by
fluorescent-activated cell sorting (FACS). Isolated, positive
receptor-ligand interactions will be identified by PCR
amplification, subcloned into a clean background, and sequenced
using plasmid-specific oligonucleotides. Subcloned proteins will be
re-screened for interaction with the labeled ligand, and their
binding patterns characterized.
[0502] Positive interacting receptor proteins may be employed in
mutagenesis or other directed evolutionary process to improve or
decrease the binding affinity to the ligand. In another
application, the receptor-ligand pair may be further employed in a
screening process to identify new compounds that may interfere with
the interaction. Thus, using a known substance to identify the
receptor and the identified receptor-ligand pair to identify other
interfering compounds. Chimeric-soluble or membrane-bound protein
libraries may be screened versus a protein-array chip that presents
a variety of known protein compounds or peptide variations. In this
application, the minicell, minicell protoplast, or minicell
poroplast will also contain a label, signaling component, and/or
antigen recognizable by an antibody for identification of a
positive interaction on the protein chip array. Other approaches
for identification may include packaged fluorescent molecules or
proteins that are constitutively produced, induced by the positive
interaction with the ligand, or regulated by a regulatory element
described in section II.B.
[0503] In a preferred embodiment of the invention, cDNA libraries
could be constructed from isolated B-cells, activated B-cell or
T-cells for the purpose of identifying receptors or antibodies that
are encoded by these cells of the immune system. In a non-limiting
example, a small molecule could be used to immunize an experimental
animal (e.g., rat, mouse, rabbit), the spleen could be removed, or
blood could be drawn and used as a source of mRNA. Reverse
transcription reactions could then be used to construct a cDNA
library that would eventually be transformed into the minicell
parent bacteria, as described above. The minicells would then be
isolated, induced and subjected to FACS analysis with subsequent
amplification and sequencing of the cDNA fragment of interest (see
above). The PCR-amplified plasmid-containing cDNA fragment encoding
the "receptor" or "antibody" of interest would be ready for
transformation and expression in the minicell context for
diagnostic, therapeutic research or screening applications of the
invention.
[0504] In a related, non-limiting embodiment of the invention,
minicells expressing a particular antigen (e.g., protein,
carbohydrate, small molecule, lipid) on their surfaces (described
elsewhere in this application) are used to generate an immunogenic
response. The advantages of presenting an antigen on the surfaces
of minicells are that the minicells themselves may be an adjuvant
that stimulates the immune response, particularly if administered
subcutaneously (SC) or intramuscularly (IM). Moreover, the
minicells are not readily eliminated by the renal system and are
present in the circulatory system of an immunized animal for a
longer time. In addition, small molecules could be tethered to the
minicell in a way that presents the desired moiety of the molecule.
Animals are presented with minicell-based immunogens, and the
antibodies produced in the animals are prepared and used in
therapeutic, diagnostic, research and screening applications.
Although this aspect of the invention may be used to make
antibodies to any molecule displayed on their surface, the
extracellular domains of membrane proteins are of particular
interest.
[0505] Minicell display could be used to identify orphan receptors
or other proteins for which a ligand or substrate is not known. As
a non-limiting example, orphan G protein coupled receptors (GPCRs)
or novel RNA and DNA polymerases could be identified from organisms
living in extreme environments. A cDNA library could be is
constructed from an organism and expressed in minicells that
co-express a reporter system that indicates the presence of the
novel protein. In a non-limiting example of GPCRs, the minicells
used for minicell display are engineered to express a G-protein in
a manner that would signal an interaction with the orphan GPCR.
VIII. Aptamers
[0506] Traditionally, techniques for detecting and purifying target
molecules have used polypeptides, such as antibodies, that
specifically bind such targets. While nucleic acids have long been
known to specifically bind other nucleic acids (e.g., ones having
complementary sequences), aptamers (i.e., nucleic acids that bind
non-nucleic target molecules) have been disclosed. See, e.g.,
Blackwell et al., Science (1990) 250:1104-1110; Blackwell et al.,
Science (1990) 250:1149-1152; Tuerk et al., Science (1990)
249:505-510; Joyce, Gene (1989) 82:83-87; and U.S. Pat. No.
5,840,867 entitled "Aptamer analogs specific for biomolecules".
[0507] As applied to aptamers, the term "binding" specifically
excludes the "Watson-Crick"-type binding interactions (i.e., A:T
and G:C base-pairing) traditionally associated with the DNA double
helix. The term "aptamer" thus refers to a nucleic acid or a
nucleic acid derivative that specifically binds to a target
molecule, wherein the target molecule is either (i) not a nucleic
acid, or (ii) a nucleic acid or structural element thereof that is
bound through mechanisms other than duplex- or triplex-type base
pairing. Such a molecule is called a "non-nucleic molecule"
herein.
[0508] VIII.A. Structures of Nucleic Acids
[0509] "Nucleic acids," as used herein, refers to nucleic acids
that are isolated a natural source; prepared in vitro, using
techniques such as PCR amplification or chemical synthesis;
prepared in vivo, e.g., via recombinant DNA technology; or by any
appropriate method. Nucleic acids may be of any shape (linear,
circular, etc.) or topology (single-stranded, double-stranded,
supercoiled, etc.). The term "nucleic acids" also includes without
limitation nucleic acid derivatives such as peptide nucleic acids
(PNA's) and polypeptide-nucleic acid conjugates; nucleic acids
having at least one chemically modified sugar residue, backbone,
internucleotide linkage, base, nucleoside, or nucleotide analog; as
well as nucleic acids having chemically modified 5' or 3' ends; and
nucleic acids having two or more of such modifications. Not all
linkages in a nucleic acid need to be identical.
[0510] Nucleic acids that are aptamers are often, but need not be,
prepared as oligonucleotides. Oligonucleotides include without
limitation RNA, DNA and mixed RNA-DNA molecules having sequences of
lengths that have minimum lengths of 2, 4, 6, 8, 10, 11, 12, 13,
14, 15, 17, 18, 19, 20, 21, 22, 23, 24 or 25 nucleotides, and
maximum lengths of about 100, 75, 50, 40, 25, 20 or 15 or more
nucleotides, irrespectively. In general, a minimum of 6
nucleotides, preferably 10 nucelotides, more preferably 14 to 20
nucleotides, is necessary to effect specific binding.
[0511] In general, the oligonucleotides may be single-stranded (ss)
or double-stranded (ds) DNA or RNA, or conjugates (e.g., RNA
molecules having 5' and 3' DNA "clamps") or hybrids (e.g., RNA:DNA
paired molecules), or derivatives (chemically modified forms
thereof). However, single-stranded DNA is preferred, as DNA is
often less labile than RNA. Similarly, chemical modifications that
enhance an aptamer's specificity or stability are preferred.
VIII.B. Chemical Modifications of Nucleic Acids
[0512] Chemical modifications that may be incorporated into
aptamers and other nucleic acids include, with neither limitation
nor exclusivity, base modifications, sugar modifications, and
backbone modifications.
[0513] Base modifications: The base residues in aptamers may be
other than naturally occurring bases (e.g., A, G, C, T, U, 5MC, and
the like). Derivatives of purines and pyrimidines are known in the
art; an exemplary but not exhaustive list includes
aziridinylcytosine, 4-acetylcytosine, 5-fluorouracil,
5-bromouracil, 5-carboxymethylaminomethyl-2-thiouracil,
5-carboxymethylaminomethyluracil, inosine, N6-isopentenyladenine,
1-methyladenine, 1-methylpseudouracil, 1-methylguanine,
1-methylinosine, 2,2-dimethylguanine, 2-methyladenine,
2-methylguanine, 3-methylcytosine, 5-methylcytosine (5MC),
N6-methyladenine, 7-methylguanine, 5-methylaminomethyluracil,
5-methoxyaminomethyl-2-thiouracil, beta-D-mannosylqueosine,
5-methoxyuracil, 2-methylthio-N-6-isopentenylade- nine,
uracil-5-oxyacetic acid methylester, pseudouracil, queosine,
2-thiocytosine, 5-methyl-2-thiouracil, 2-thiouracil, 4-thiouracil,
5-methyluracil, uracil-5-oxyacetic acid, and 2,6-diaminopurine. In
addition to nucleic acids that incorporate one or more of such base
derivatives, nucleic acids having nucleotide residues that are
devoid of a purine or a pyrimidine base may also be included in
aptamers.
[0514] Sugar modifications: The sugar residues in aptamers may be
other than conventional ribose and deoxyribose residues. By way of
non-limiting example, substitution at the 2'-position of the
furanose residue enhances nuclease stability. An exemplary, but not
exhaustive list, of modified sugar residues includes 2' substituted
sugars such as 2'-O-methyl-, 2'-O-alkyl, 2'-O-allyl, 2'-S-alkyl,
2'-S-allyl, 2'-fluoro-, 2'-halo, or 2'-azido-ribose, carbocyclic
sugar analogs, alpha-anomeric sugars, epimeric sugars such as
arabinose, xyloses or lyxoses, pyranose sugars, furanose sugars,
sedoheptuloses, acyclic analogs and abasic nucleoside analogs such
as methyl riboside, ethyl riboside or propylriboside.
[0515] Backbone modifications: Chemically modified backbones
include, by way of non-limiting example, phosphorothioates, chiral
phosphorothioates, phosphorodithioates, phosphotriesters,
aminoalkylphosphotriesters, methyl and other alkyl phosphonates
including 3'-alkylene phosphonates and chiral phosphonates,
phosphinates, phosphoramidates including 3'-amino phosphoramidate
and aminoalkylphosphoramidates, thionophosphoramidates,
thionoalkylphosphonates, thionoalkylphosphotriesters, and
boranophosphates having normal 3'-5' linkages, 2'-5' linked analogs
of these, and those having inverted polarity wherein the adjacent
pairs of nucleoside units are linked 3'-5' to 5'-3' or 2'-5' to
5'-2'. Chemically modified backbones that do not contain a
phosphorus atom have backbones that are formed by short chain alkyl
or cycloalkyl internucleoside linkages, mixed heteroatom and alkyl
or cycloalkyl internucleoside linkages, or one or more short chain
heteroatomic or heterocyclic internucleoside linkages, including
without limitation morpholino linkages; siloxane backbones;
sulfide, sulfoxide and sulfone backbones; formacetyl and
thioformacetyl backbones; methylene formacetyl and thioformacetyl
backbones; alkene containing backbones; sulfamate backbones;
methyleneimino and methylenehydrazino backbones; sulfonate and
sulfonamide backbones; and amide backbones.
[0516] VIII.C. Preparation and Identification of Aptamers
[0517] In general, techniques for identifying aptamers involve
incubating a preselected non-nucleic target molecule with mixtures
(2 to 50 members), pools (50 to 5,000 members) or libraries (50 or
more members) of different nucleic acids that are potential
aptamers under conditions that allow complexes of target molecules
and aptamers to form. By "different nucleic acids" it is meant that
the nucleotide sequence of each potential aptamer may be different
from that of any other member, that is, the sequences of the
potential aptamers are random with respect to each other.
Randomness can be introduced in a variety of manners such as, e.g.,
mutagenesis, which can be carried out in vivo by exposing cells
harboring a nucleic acid with mutagenic agents, in vitro by
chemical treatment of a nucleic acid, or in vitro by biochemical
replication (e.g., PCR) that is deliberately allowed to proceed
under conditions that reduce fidelity of replication process;
randomized chemical synthesis, i.e., by synthesizing a plurality of
nucleic acids having a preselected sequence that, with regards to
at least one position in the sequence, is random. By "random at a
position in a preselected sequence" it is meant that a position in
a sequence that is normally synthesized as, e.g., as close to 100%
A as possible (e.g., 5'-C-T-T-A-G-T-3') is allowed to be randomly
synthesized at that position (C-T-T-N-G-T, wherein N indicates a
randomized position where, for example, the synthesizing reaction
contains 25% each of A,T,C and G; or x % A, w % T, y % C and z % G,
wherein x+w+y+z=100. In later stages of the process, the sequences
are increasingly less randomized and consensus sequences may
appear; in any event, it is preferred to ultimately obtain an
aptamer having a unique nucleotide sequence.
[0518] Aptamers and pools of aptamers are prepared, identified,
characterized and/or purified by any appropriate technique,
including those utilizing in vitro synthesis, recombinant DNA
techniques, PCR amplification, and the like. After their formation,
target:aptamer complexes are then separated from the uncomplexed
members of the nucleic acid mixture, and the nucleic acids that can
be prepared from the complexes are candidate aptamers (at early
stages of the technique, the aptamers generally being a population
of a multiplicity of nucleotide sequences having varying degrees of
specificity for the target). The resulting aptamer (mixture or
pool) is then substituted for the starting apatamer (library or
pool) in repeated iterations of this series of steps. When a
limited number (e.g., a pool or mixture, preferably a mixture with
less than 100 members, more preferably less than 10 members, most
preferably 1, of nucleic acids having satisfactory specificity is
obtained, the aptamer is sequenced and characterized. Pure
preparations of a given aptamer are generated by any appropriate
technique (e.g., PCR amplification, in vitro chemical synthesis,
and the like).
[0519] For example, Tuerk and Gold (Science (1990) 249:505-510)
disclose the use of a procedure termed "systematic evolution of
ligands by exponential enrichment" (SELEX). In this method, pools
of nucleic acid molecules that are randomized at specific positions
are subjected to selection for binding to a nucleic acid-binding
protein (see, e.g., PCT International Publication No. WO 91/19813
and U.S. Pat. No. 5,270,163). The oligonucleotides so obtained are
sequenced and otherwise characterization. Kinzler, K. W., et al.
(Nucleic Acids Res. (1989) 17:3645-3653) used a similar technique
to identify synthetic double-stranded DNA molecules that are
specifically bound by DNA-binding polypeptides. Ellington, A. D.,
et al. (Nature (1990) 346: 818-822) disclose the production of a
large number of random sequence RNA molecules and the selection and
identification of those that bind specifically to specific dyes
such as Cibacron blue.
[0520] Another technique for identifying nucleic acids that bind
non-nucleic target molecules is the oligonucleotide combinatorial
technique disclosed by Ecker, D. J. et al. (Nuc. Acids Res. 21,
1853 (1993)) known as "synthetic unrandomization of randomized
fragments" (SURF), which is based on repetitive synthesis and
screening of increasingly simplified sets of oligonucleotide
analogue libraries, pools and mixtures (Tuerk et al., Science
249:505, 1990). The starting library consists of oligonucleotide
analogues of defined length with one position in each pool
containing a known analogue and the remaining positions containing
equimolar mixtures of all other analogues. With each round of
synthesis and selection, the identity of at least one position of
the oligomer is determined until the sequences of optimized nucleic
acid ligand aptamers are discovered.
[0521] Once a particular candidate aptamer has been identified
through a SURF, SELEX or any other technique, its nucleotide
sequence can be determined (as is known in the art), and its
three-dimensional molecular structure can be examined by nuclear
magnetic resonance (NMR). These techniques are explained in
relation to the determination of the three-dimensional structure of
a nucleic acid ligand that binds thrombin in Padmanabhan et al., J.
Biol. Chem. 24, 17651 (1993); Wang et al., Biochemistry 32, 1899
(1993); and Macaya et al., Proc. Nat'l. Acad. Sci. USA 90, 3745
(1993). Selected aptamers may be resynthesized using one or more
modified bases, sugars or backbone linkages. Aptamers consist
essentially of the minimum sequence of nucleic acid needed to
confer binding specificity, but may be extended on the 5' end, the
3' end, or both, or may be otherwise derivatized or conjugated.
IX. Polypeptidic Binding Moieties
[0522] A variety of binding moities can be attached to a minicell
of the invention for a variety of purposes. In a preferred
embodiment, the binding moiety is directed to a ligand that is
displayed by a cell into which it is desired to deliver the
therapeutic content of a minicell.
[0523] IX.A. Antibodies and Antibody Derivatives
[0524] The term "antibody" is meant to encompass an immunoglobulin
molecule obtained by in vitro or in vivo generation of an
immunogenic response, and includes polyclonal, monospecific and
monoclonal antibodies, as well as antibody derivatives, e.g.
single-chain antibody fragments (scFv). An "immunogenic response"
is one that results in the production of antibodies directed to one
or more proteins after the appropriate cells have been contacted
with such proteins, or polypeptide derivatives thereof, in a manner
such that one or more portions of the protein function as epitopes.
An epitope is a single antigenic determinant in a molecule. In
proteins, particularly denatured proteins, an epitope is typically
defined and represented by a contiguous amino acid sequence.
However, in the case of nondenatured proteins, epitopes also
include structures, such as active sites, that are formed by the
three-dimensional folding of a protein in a manner such that amino
acids from separate portions of the amino acid sequence of the
protein are brought into close physical contact with each
other.
[0525] Wildtype antibodies have four polypeptide chains, two
identical heavy chains and two identical light chains. Both types
of polypeptide chains have constant regions, which do not vary or
vary minimally among antibodies of the same class (i.e., IgA, IgM,
etc.), and variable regions. Variable regions are unique to a
particular antibody and comprise an "antigen binding domain" that
recognizes a specific epitope. Thus, an antibody's specificity is
determined by the variable regions located in the amino terminal
regions of the light and heavy chains.
[0526] As used herein, the term "antibody" encompasses derivatives
of antibodies such as antibody fragments that retain the ability to
specifically bind to antigens. Such antibody fragments include Fab
fragments (i.e., an antibody fragment that contains the
antigen-binding domain and comprises a light chain and part of a
heavy chain bridged by a disulfide bond); Fab' (an antibody
fragment containing a single anti-binding domain comprising an Fab
and an additional portion of the heavy chain through the hinge
region); F(ab')2 (two Fab' molecules joined by interchain disulfide
bonds in the hinge regions of the heavy chains; the Fab' molecules
may be directed toward the same or different epitopes); a
bispecific Fab (an Fab molecule having two antigen binding domains,
each of which may be directed to a different epitope); a single
chain Fab chain comprising a variable region, a.k.a., a sFv (the
variable, antigen-binding determinative region of a single light
and heavy chain of an antibody linked together by a chain of about
10 to about 25 amino acids).
[0527] The term "antibody" includes antibodies and antibody
derivatives that are produced by recombinant DNA techniques and
"humanized" antibodies. Humanized antibodies have been modified, by
genetic manipulation and/or in vitro treatment to be more human, in
terms of amino acid sequence, glycosylation pattern, etc., in order
to reduce the antigenicity of the antibody or antibody fragment in
an animal to which the antibody is intended to be administered
(Gussow et al., Methods Enz. 203:99-121, 1991).
[0528] A single-chain antibody (scFv) is a non-limiting example of
a binding moiety that may be displayed on minicells. Single-chain
antibodies are produced by recombinant DNA technology and may be
incorporated into fusion proteins. The term "single chain" denotes
the fact that scFv's are found in a single polypeptide. In
contrast, wildtype antibodies have four polypeptide chains, two
identical heavy chains and two identical light chains. Both types
of polypeptide chains have constant regions, which do not vary or
vary minimally among antibodies of the same class (i.e., IgA, IgM,
etc.), and variable regions. An antibody's specificity is
determined by the variable regions located in the amino terminal
regions of the light and heavy chains. The variable regions of a
light chain and associated heavy chain form an "antigen binding
domain" that recognizes a specific epitope. In a single chain
antibody, the amino acid sequences of the variable light and
variable heavy regions of an antibody are present in one comtiguous
polypeptide. Methods of producing single chain antibodies are known
in the art. See, for example, U.S. Pat. Nos. 4,946,778; 5,260,203;
5,455,030; 5,518,889; 5,534,621; 5,869,620; 6,025,165; 6,027,725
and 6,121,424.
[0529] Antibody derivatives and other polypeptides that are binding
moieties can be isolated from protein display libraries, in which a
library of candidate binding agents is displayed on a phage or
other agent that comprises a nucleic acid encoding the protein it
displays. Thus, an agent that binds to the target compound can be
isolated, and nucleic acid prepared therefrom, providing for the
rapid isolation of binding moieties and nucleic acids that can be
used to produce them. For reviews, see Benhar I. Biotechnological
applications of phage and cell display. Biotechnology Adv. 2001
(19): 1-33; FitzGerald K. In vitro display technologie--new tools
for drug discovery. Drug Discov Today. 2000 5(6):253-258; and
Hoogenboom H R, Chames P. Natural and designer binding sites made
by phage display technology. Immunol Today. 2000
August;21(8):371-8.
[0530] A variety of protein display systems are known in the art
and include various phage display systems such as those described
in Jung S, Arndt K, Muller K, Pluckthyn A. Selectively infective
phage (SIP) technology: scope and limitations. J Immunol Methods.
1999 (231):93-104; Katz B. Structural and mechanistic determinants
of affinity and specificity of ligands discovered or engineered by
phage display. Annu Rev Biophys Biomol Struct. 1997 (26):27-45;
Forrer P, Jung S, Pluckthun A. Beyond binding: using phage display
to select for structure, folding and enzymatic activity in
proteins. Curr Opin Struct Biol. 1999 Aug;9(4):514-20; Rondot S,
Koch J, Breitling F, Dubel S. A helper phage to improve
single-chain antibody presentation in phage display. Nat
Biotechnol. 2001 January;19(1):75-8. Giebel L B, Cass R T, Milligan
D L, Young D C, Arze R, Johnson C R. Screening of cyclic peptide
phage libraries identifies ligands that bind streptavidin with high
affinities. Biochemistry. Nov. 28, 1995 ;34(47):15430-5; de Kruif
J, Logtenberg T. Leucine zipper dimerized bivalent and bispecific
scFv antibodies from a semi-synthetic antibody phage display
library. J Biol Chem. Mar. 29, 1996 ;271(13):7630-4; Hoogenboom H
R, Henderikx P, de Haard H. Creating and engineering human
antibodies for immunotherapy. Adv Drug Deliv Rev. Apr. 6,
1998;31(1-2):5-31; Helfrich W, Haisma H J, Magdolen V, Luther T,
Bom V J, Westra J, van der Hoeven R, Kroesen B J, Molema G, de Leij
L. A rapid and versatile method for harnessing scFv antibody
fragments with various biological effector functions. J Immunol
Methods. Apr. 3, 2000;237(1-2):131-45; Hoess R H. Bacteriophage
lambda as a vehicle for peptide and protein display. Curr Pharm
Biotechnol 2002 March;3(1):23-8; Baek H, Suk K H, Kim Y H, Cha S.
An improved helper phage system for efficient isolation of specific
antibody molecules in phage display. Nucleic Acids Res. Mar. 1,
2002;30(5):e18; and Rondot S, Koch J, Breitling F, Dubel S. A
helper phage to improve single-chain antibody presentation in phage
display. Nat Biotechnol. 2001 January;19(1):75-8.
[0531] Other display systems include without limitation "Yeast
Display" (Curr Opin Biotechnol 1999 October; 10(5):422-7.
Applications of yeast in biotechnology: protein production and
genetic analysis. Cereghino G P, Cregg J M.); "Baculovirus Display"
(Kost T A, Condreay J P. Recombinant baculoviruses as expression
vectors for insect and mammalian cells. Curr Opin Biotechnol. 1999
October;10(5):428-33; and Liang M, Dubel S, Li D, Queitsch I, Li W,
Bautz E K. Baculovirus expression cassette vectors for rapid
production of complete human IgG from phage display selected
antibody fragments. J Immunol Methods. Jan. 1,
2001;247(1-2):119-30); "Ribosome Display" (Hanes J, Schaffitzel C,
Knappik A, Pluckthun A. Picomolar affinity antibodies from a fully
synthetic naive library selected and evolved by ribosome display.
Nat Biotechnol. 2000 December; 18(12):1287-92; Hanes J, Jermutus L,
Pluckthun A. Selecting and evolving functional proteins in vitro by
ribosome display. Methods Enzymol. 2000;328:404-30; Schaffitzel C,
Hanes J, Jermutus L, Pluckthun A. Ribosome display: an in vitro
method for selection and evolution of antibodies from libraries. J
Immunol Methods. Dec. 10, 1999;231(1-2):119-35; Hanes J, Jermutus
L, Weber-Bornhauser S, Bosshard H R, Pluckthun A. Ribosome display
efficiently selects and evolves high-affinity antibodies in vitro
from immune libraries. Proc Natl Acad Sci U S A. Nov. 24,
1998;95(24): 14130-5; Hanes J, Pluckthun A. In vitro selection and
evolution of functional proteins by using ribosome display. Proc
Natl Acad Sci U S A. May 13, 1997;94(10):4937-42; Coia G,
Pontes-Braz L, Nuttall S D, Hudson P J, Irving R A. Panning and
selection of proteins using ribosome display. J Immunol Methods.
Aug. 1, 2001;254(1-2):191-7.; Irving R A, Coia G, Roberts A,
Nuttall S D, Hudson P J. Ribosome display and affinity maturation:
from antibodies to single V-domains and steps towards cancer
therapeutics. J Immunol Methods. Feb. 1, 2001; 248(1-2):31-45); and
"Bacterial Display" (Hoischen C, Fritsche C, Gumpert J, Westermann
M, Gura K, Fahnert B. Novel bacterial membrane surface display
system using cell wall-less L-forms of Proteus mirabilis and
Escherichia coli. Appl Environ Microbiol. 2002 February
;68(2):525-31; Etz H, Minh D B, Schellack C, Nagy E, Meinke A.
Bacterial phage receptors, versatile tools for display of
polypeptides on the cell surface. J Bacteriol. 2001
December;183(23):6924-35; Patel D, Vitovski S, Senior H J, Edge M
D, Hockney R C, Dempsey M J, Sayers J R. Continuous affinity-based
selection: rapid screening and simultaneous amplification of
bacterial surface-display libraries. Biochem J. Aug. 1, 2001;357(Pt
3):779-85; Lang H. Outer membrane proteins as surface display
systems. Int J Med Microbiol. 2000 December;290(7):579-85; Earhart
C F. Use of an Lpp-OmpA fusion vehicle for bacterial surface
display. Methods Enzymol. 2000;326:506-16; Benhar I, Azriel R,
Nahary L, Shaky S, Berdichevsky Y, Tamarkin A, Wels W. Highly
efficient selection of phage antibodies mediated by display of
antigen as Lpp-OmpA' fusions on live bacteria. J Mol Biol. Aug. 25,
2000;301(4):893-904; Xu Z, Lee S Y. Display of polyhistidine
peptides on the Escherichia coli cell surface by using outer
membrane protein C as an anchoring motif. Appl Environ Microbiol.
1999 November;65(11):5142-7; Daugherty P S, Olsen M J, Iverson B L,
Georgiou G. Development of an optimized expression system for the
screening of antibody libraries displayed on the Escherichia coli
surface. Protein Eng. 1999 July;12(7):613-21; Chang H J, Sheu S Y,
Lo S J. Expression of foreign antigens on the surface of
Escherichia coli by fusion to the outer membrane protein traT. J
Biomed Sci. 1999 January;6(1):64-70; Maurer J, Jose J, Meyer T F.
Autodisplay: one-component system for efficient surface display and
release of soluble recombinant proteins from Escherichia coli. J
Bacteriol. 1997 February ; 179(3):794-804.
[0532] Antibodies, particularly single-chain antibodies, directed
to surface antigens specific for a particular cell type may also be
used as cell- or tissue-specific targeting elements. Single-chain
antibody amino acid sequences have been incorporated into a variety
of fusion proteins, including those with transmembrane domains
and/or membrane-anchoring domains. See, for example, Kuroki et al.,
"Specific Targeting Strategies of Cancer Gene Therapy Using a
Single-Chain Variable Fragment (scFv) with a High Affinity for
CEA," Anticancer Res., pp. 4067-71, 2000; U.S. Pat. No. 6,146,885,
to Dornburg, entitled "Cell-Type Specific Gene Transfer Using
Retroviral Vectors Containing Antibody-Envelope Fusion Proteins";
Jiang et al., "In Vivo Cell Type-Specific Gene Delivery With
Retroviral Vectors That Display Single Chain Antibodies," Gene
Ther. 1999, 6:1982-7; Engelstadter et al., "Targeting Human T Cells
By Retroviral Vectors Displaying Antibody Domains Selected From A
Phage Display Library," Hum. Gene Ther. 2000, 11:293-303; Jiang et
al., "Cell-Type-Specific Gene Transfer Into Human Cells With
Retroviral Vectors That Display Single-Chain Antibodies," J. Virol
1998,72:10148-56; Chu et al., "Toward Highly Efficient
Cell-Type-Specific Gene Transfer With Retroviral Vectors Displaying
Single-Chain Antibodies," J. Virol 1997, 71:720-5; Chu et al.,
"Retroviral Vector Particles Displaying The Antigen-Binding Site Of
An Antibody Enable Cell-Type-Specific Gene Transfer," J. Virol
1995, 69:2659-63; Chu et al., "Cell Targeting With Retroviral
Vector Particles Containing Antibody-Envelope Fusion Proteins, "
Gene Ther. 1994, 1:292-9; Esshar et al., "Specific activation and
targeting of cytotoxic lymphocytes through chimeric single chains
consisting of antibody-binding domains and the or subunits of the
immunoglobulin and T-cell receptors," Proc. Natl. Acad. Sci. USA,
1993, Vol. 90:720-724; Einfeld et al., "Construction of a
Pseudoreceptor That Mediates Transduction by Adenoviruses
Expressing a Ligand in Fiber or Penton Base," J. Virol. 1999,
73:9130-9136; Marin et al., "Targeted Infection of Human Cells via
Major Histocompatibility Complex Class I Molecules by Moloney
Murine Leukemia Virus-Derived Viruses Displaying Single-Chain
Antibody Fragment-Envelope Fusion Proteins," J. Virol., 1996,
70:2957-2962; Somia et al., "Generation of targeted retroviral
vectors by using single-chain variable fragment: An approach to in
vivo gene delivery," Proc. Natl. Acad. Sci. USA, 1995,
92:7570-7574; Liu et al., "Treatment of B-Cell Lymphoma With
Chimeric IgG and Single-Chain Fv Antibody-Interleukin-2 Fusion
Proteins," Blood, 1998, 92:2103-2112; Martin et al., "Retrovirus
Targeting by Tropism Restriction to Melanoma Cells," J. Virol.,
1999, 73:6923-6929; Ramjiawan et al., "Noninvasive Localization of
Tumors by Immunofluorescence Imaging Using a Single Chain Fv
Fragment of a Human Monoclonal Antibody with Broad Cancer
Specificity," Amer. Cancer Society, 2000, 89:1134-1144; Snitkovsky
et al., "A TVA-Single-Chain Antibody Fusion Protein Mediates
Specific Targeting of a Subgroup A Avian Leukosis Virus Vector to
Cells Expressing a Tumor-Specific Form of Epidermal Growth Factor
Receptor," J. Virol., 2000, 74:9540-9545; Chu et al., "Toward
Highly Efficient Cell-Type-Specific Gene Transfer with Retroviral
Vectors Displaying Single-Chain Antibodies," J. Virol., 1997,
71:720-725; Kulkarni et al.,Programmed cell death signaling via
cell-surface expression of a single-chain antibody transgene,
Transplantation Mar. 27, 2000;69(6): 1209-17.
[0533] IX.B. Non-Catalytic Derivatives of Active Sites of
Enzymes
[0534] Enzymes bind their substrates, at least transiently, in
regions known as "active sites." It is known in the art that
non-catalytic derivatives of enzymes, which bind but do not
chemically alter their substrates may be prepared. Non-catalytic
enzymes, particularly the mutant active sites thereof, are used to
bind substrate molecules.
[0535] As a non-limiting example, enzymes from which biologically
inactive (non-catalytic) sphingolipid-binding derivatives are
obtained. Such derivatives of these enzymes bind their substrate
sphingolipid. Sphingosine-1-phosphate (S1P) is bound by
non-catalytic derivatives of enzymes having S1P as a substrate,
e.g., S1P lyase and S1P phosphatase. Sphingosine (SPH) is bound by
non-catalytic derivatives of enzymes having SPH as a substrate,
e.g., SPH kinase and ceramide synthase. Ceramide (CER) is bound by
non-catalytic derivatives of enzymes having CER as a substrate,
such as, by way of non-limiting example, ceramidase, sphingomyelin
synthase, ceramide kinase, and glucosylceramide synthase.
Sphingomyelin is bound by non-catalytic derivatives of
sphingomyelinase, an enzyme having sphingomyelin as a
substrate.
[0536] IX.C. Nucleic Acid Binding Domains
[0537] Nucleic acid binding polypeptide domains may bind nucleic
acids in a sequence-dependent or sequence-independent fashion
and/or in a manner that is specific for various nucleic acids
having different chemical structures (e.g., single- or
double-stranded DNA or RNA, RNA:DNA hybrid molecules, etc.).
Non-limiting examples of membrane-based transcription factors and
DNA-binding protein include Smad proteins (Miyazono et al.,
TGF-beta signaling by Smad proteins (Review), Adv Immunol
75:115-57, 2000); SREBPs (sterol regulatory element binding
proteins) (Ye et al., Asparagine-proline sequence within
membrane-spanning segment of SREBP triggers intramembrane cleavage
by site-2 protease, Proc Natl Acad Sci USA 97:5123-8, 2000;
Shimomura et al., Cholesterol feeding reduces nuclear forms of
sterol regulatory element binding proteins in hamster liver, Proc
Natl Acad Sci USA 94:12354-9, 1997; Brown and Goldstein, The SREBP
pathway: regulation of cholesterol metabolism by proteolysis of a
membrane-bound transcription factor (Review), Cell 89:331-40, 1997;
Scheek et al., Sphingomyelin depletion in cultured cells blocks
proteolysis of sterol regulatory element binding proteins at site
1, Proc Natl Acad Sci USA 94:11179-83, 1997); mitochondrial
DNA-binding membrane proteins, e.g., Abf2p and YhmZp (Cho et al., A
novel DNA-binding protein bound to the mitochondrial inner membrane
restores the null mutation of mitochondrial histone Abf2p in
Saccharomyces cerevisiae, Mol Cell Biol 18:5712-23, 1998); and
bacterial DNA-binding membrane proteins (Smith et al.,
Transformation in Bacillus subtilis: purification and partial
characterization of a membrane-bound DNA-binding protein., J
Bacteriol 156:101-8, 1983).
[0538] IX.D. Attaching Binding Moities, or Other Compounds, to
Minicells Binding compounds or moieties can be chemically attached
(conjugated) to minicells via membrane proteins that are displayed
on the minicells. The compound to be conjugated to minicells (the
"attachable compound") may of any chemical composition, i.e., a
small molecule, a nucleic acid, a radioisotope, a lipid or a
polypeptide. One type of attachable compound that can be covalently
attached to minicells is a binding moitiety, e.g., an antibody or
antibody derivative. Another non-limiting example of attachable
compounds is polyethylene glycol ("PEG"), which lowers the uptake
in vivo of minicells by the reticuloendothelical system (RES).
Another non-limiting example of creating stealth minicells to avoid
the RES is to express proteins or other molecules on the surfaces
of minicells whose lipid compositions have been modified, such as
anionic lipid-rich minicells.
[0539] By way of non-limiting example, it is possible to prepare
minicells that express transmembrane proteins with cysteine
moieties on extracellular domains. Linkage of the membrane protein
may be achieved through surface cysteinyl groups by, e.g.,
reduction with cysteinyl residues on other compounds to form
disulfide bridges (S.dbd.S). If appropriate cysteinyl residues are
not present on the membrane protein they may be introduced by
genetic manipulation. The substitution of cysteine for another
amino acid may be achieved by methods well-known to those skilled
in the art, for example, by using methods described in Maniatis,
Sambrook, and Fritsch (Molecular Cloning: A Laboratory Manual, Cold
Spring Harbor Laboratory Press, 1989). As a non-limiting example,
bioactive lysosphingolipids (e.g., sphingosine,
sphingosine-1-phosphate, sphingosylphosphoryl choline) are
covalently linked to proteins expressed on the surfaces of
minicells such that these bioactive lipids are on the surface of
the minicells and accessible for therapeutic or diagnostic uses in
vivo or in vitro.
[0540] When the attachable moiety and the membrane protein both
have a reduced sulfhydryl group, a homobifunctional cross-linker
that contains maleimide, pyridyl disulfide, or
beta-alpha-haloacetyl groups may be used for cross-linking.
Examples of such cross-linking reagents include, but are not
limited to, bismaleimidohexane (BMH) or 1,4-Di-[3'-(2'-pyridyldit-
hio)propionamido]butane (DPDPB). Alternatively, a
heterobifunctional cross-linker that contains a combination of
maleimide, pyridyl disulfide, or beta-alpha-haloacetyl groups can
be used for cross-linking.
[0541] As another non-limiting example, attachable moieties may be
chemically conjugated using primary amines. In these instances, a
homobifunctional cross-linker that contains succiminide ester,
imidoester, acylazide, or isocyanate groups may be used for
cross-linking. Examples of such cross-linking reagents include, but
are not limited to: Bis[2-(succinimidooxycarbonyloxy)ethyl]sulfone
(BSOCOES); Bis[2-(sulfosuccinimidooxycarbonyloxy)ethyl]sulfone
(sulfo-BSCOCOES); Disuccinimidyl suberate (DSS);
Bis-(Sulfosuccinimidyl) Suberate (BS3); Disuccinimidyl glutarate
(DSG); Dithiobis(succinimidylpropionate) (DSP);
Dithiobois(sulfosuccinimidylpropionate) (DTSSP);
Disulfosuccinimidyl tartrate (sulfo-DST);
Dithio-bis-maleimidoethane (DTME); Disuccinimidyl tartrate (DST);
Ethylene glycolbis(sulfosuccinimidylsuccinate) (sulfo-EGS);
Dimethyl malonimidate.cndot.2 HCl (DMM); Ethylene
glycolbis(succinimidylsuccinate) (EGS); Dimethyl
succinimidate.cndot.2 HCl (DMSC); Dimethyl adipimidate.cndot.2 HCl
(DMA); Dimethyl pimelimidate.cndot.2 HCl (DMP); and Dimethyl
suberimidate.cndot.2.cndot.H- Cl (DMS), and Dimethyl
3,3'-dithiobispropionimidate.cndot.2 HCl (DTBP). Heterobifunctional
cross-linkers that contains a combination of imidoester or
succinimide ester groups may also be used for cross-linking.
[0542] As another non-limiting example, attachable moieties may be
chemically conjugated using sulfhydryl and primary amine groups. In
these instances, heterobifunctional cross-linking reagents are
preferable used. Examples of such cross-linking reagents include,
but are not limited to: N-succinimidyl
3-(2-pyridyldithio)propionate (DPDP); N-succinimidyl
6-[3'-(2-pyridyldithio)-propionamido] hexanoate (sulfo-LC-SPDP);
m-maleimidobenzoyl-N-hydoxysuccinimide ester (MBS);
m-maleimidobenzoyl-N-hydoxysulfosuccinimide ester (sulfo-MBS);
succinimidyl 4-[P-maleimidophenyl] butyrate (SMPB);
sulfosuccinimidyl 4-[p-maleimidophenyl] butyrate (sulfo-SMPB);
N-[.gamma.-Maleimidobutyrylo- xy] succinimide ester (GMBS),
N-[.gamma.-maleimidobutyryloxy] sulfosuccinimide ester
(sulfo-GMBS); N-[.epsilon.-maleimidocaproyloxy] succinimide ester
(EMCS); N-[.epsilon.-maleimidocaproyloxy] sulfosuccinimide ester
(sulfo-EMCS); N-succinimidyl(4-iodoacetyl)aminoben- zoate (SIAB);
sulfosuccinimidyl(4-iodacetyl)aminobenzoate (sulfo-SIAB);
succinimidyl 4-(N-maleimidomethyl)cyclohexane-1-carboxylate (SMCC);
sulfosuccinimidyl 4-(N-maleimidomethyl)cyclohexane-1-carboxylate
(sulfo-SMCC);
succiminidyl-4-(N-maleimidomethyl)cyclohexane-1-carboxy-(6--
amido-caproate) (LC-SMCC);
4-succinimidyloxycarbonyl-methyl-(2-pyridyldith- io) toluene
(SMPT); and sulfo-LC-SMPT.
[0543] As an exemplary protocol, a minicell suspension is made 5 mM
EDTA/PBS, and a reducing solution of 2-mercaptoethylamine in 5 mM
EDTA/PBS is added to the minicells. The mixture is incubated for 90
minutes at 37.degree. C. The minicells are washed with EDTA/PBS to
remove excess 2-mercaptoethylamine. The attachable moiety is
dissolved in PBS, pH 7.2. A maleimide crosslinker is added to the
solution, which is then incubated for 1 hour at room temperature.
Excess maleimide is removed by column chromatography.
[0544] The minicells with reduced sulfhydryl groups are mixed with
the derivatized compounds having an attachable moiety. The mixture
is allowed to incubate at 4.degree. C. for 2 hours or overnight to
allow maximum coupling. The conjugated minicells are washed to
remove unreacted (unattached) compounds having the attachable
moiety. Similar protocols are used for expressed membrane proteins
with other reactive groups (e.g., carboxyl, amine) that can be
conjugated to an attachable moiety.
[0545] IX.E. Non-Genetic Methods for Directing Compounds to
Membranes
[0546] Included within the scope of the invention are compounds
that can be inserted into the membrane of segregated minicells.
Such compounds include attachable moieties that are chemically
conjugated to the surface of a minicell, and compounds that
associate with and/or insert into a membrane "spontaneously," i.e.,
by virtue of their chemical nature. By way of non-limiting example,
proteins that "spontaneously" insert into membranes include but are
not limited to Thykaloid membrane proteins (Woolhead et al., J.
Biol. Chem. 276:14607-14613, 2001), the mitochondrial adenine
nucleotide translocator (Jacotot et al., J. Exp. Med. 193:509-519,
2001), and polypeptides obtained using the methods of Hunt et al.
(Spontaneous, pH-dependent membrane insertion of a transbilayer
alpha-helix, Biochem 36:15177-15192, 1997). Lipids, gangliosides,
sphingomyelins, plasmalogens glycosyl diacylglycerols, and sterols
can also be incorporated into the membranes of segregated
minicells.
[0547] X. Membrane Proteins
[0548] In certain aspects of the invention, membrane proteins from
non-eubacterial organisms are expressed and displayed by minicells.
The cellular membrane (a.k.a. the "plasma membrane") is a lipid
bilayer that forms the boundary between the interior of a cell and
its external environment. The term "membrane proteins" refers to
proteins that are found in membranes including without limitation
cellular and organellar membranes.
[0549] X.A. Types of Membrane Proteins
[0550] X.A.1. In General
[0551] Membrane proteins consist, in general, of two types,
peripheral membrane proteins and integral membrane proteins.
[0552] Integral membrane proteins can span both layers (or
"leaflets") of a lipid bilayer. Thus, such proteins may have
extracellular, transmembrane, and intracellular domains.
Extracellular domains are exposed to the external environment of
the cell, whereas intracellular domains face the cytosol of the
cell. The portion of an integral membrane protein that traverses
the membrane is the "transmembrane domain." Transmembrane domains
traverse the cell membrane often by one or more regions comprising
15 to 25 hydrophobic amino acids which are predicted to adopt an
alpha-helical conformation.
[0553] Integral membrane proteins are classified as bitopic or
polytopic (Singer, (1990) Annu. Rev. Cell Biol. 6:247-96). Bitopic
proteins span the membrane once while polytopic proteins contain
multiple membrane-spanning segments.
[0554] A peripheral membrane protein is a membrane protein that is
bound to the surface of the membrane and is not integrated into the
hydrophobic layer of a membrane region. Peripheral membrane
proteins do not span the membrane but instead are bound to the
surface of a membrane, one layer of the lipid bilayer that forms a
membrane, or the extracellular domain of an integral membrane
protein.
[0555] X.A.2. In General
[0556] The invention can be applied to any membrane protein,
including but not limited to the following exemplary receptors and
membrane proteins. The proteins include but are not limited to are
receptors (e.g., GPCRs, sphingolipid receptors, neurotransmitter
receptors, sensory receptors, growth factor receptors, hormone
receptors, chemokine receptors, cytokine receptors, immunological
receptors, and compliment receptors, FC receptors), channels (e.g.,
potassium channels, sodium channels, calcium channels.), pores
(e.g., nuclear pore proteins, water channels), ion and other pumps
(e.g., calcium pumps, proton pumps), exchangers (e.g.,
sodium/potassium exchangers, sodium/hydrogen exchangers,
potassium/hydrogen exchangers), electron transport proteins (e.g.,
cytochrome oxidase), enzymes and kinases (e.g., protein kinases,
ATPases, GTPases, phosphatases, proteases.), structural/linker
proteins (e.g., Caveolins, clathrin), adapter proteins (e.g., TRAD,
TRAP, FAN), chemotactic/adhesion proteins (e.g., ICAM11, selectins,
CD34, VCAM-1, LFA-1,VLA-1), and phospholipases such as PI-specific
PLC and other phospholipiases.
[0557] X.A.3. Receptors
[0558] Within the scope of the invention are any receptor,
including without limitation:
[0559] The nuclear receptors, e.g. the nuclear export receptor;
[0560] The peripheral (mitochondrial) benzodiazephine receptor
(Gavish et al., "Enigma of the Peripheral Benzodiazephine
Receptor," Pharmacological Reviews, Vol. 51, No. 4);
[0561] Adrenergic and muscarinic receptors (Brodde et al.,
"Adrenergic and Muscarinic Receptors in the Human Heart",
Pharmacological Review, Vol. 51, No. 4);
[0562] Gamma-aminobutyric acidA receptors (Barnard et al.,
"International Union of Pharmacology. IV. Subtypes of
.gamma.-Aminobutyric Acid.sub.A Receptors: Classification on the
Basis of Submit Structure and Receptor Function," Pharmacological
Reviews, Vol. 50, No. 2);
[0563] Kinin B1 receptors (Marceau et al., "The B.sub.1 Receptors
for Kinins," Pharmacological Reviews, Vol. 50, No. 3);
[0564] Chemokine receptors (Murphy et al., "International Union of
Pharmacology. XXII. Nomenclature for Chemokine Receptors"
Pharmacological Reviewa, Vol. 52, No. 1);
[0565] Glycine and NMDA Receptors (Danysz et al., "Glycine and
N-Methyl-D-Aspartate Receptors: Physiological Significance and
Possible Therapeutic Applications," Pharmacological Reviews, Vol.
50, No. 4);
[0566] Glutamate receptor ion channels (Dingledine et al., "The
Glutamate Receptor Ion Channels", Pharmacological Reviews, Vol. 51,
No. 1);
[0567] Purine and pyrimidine receptors including purinergic (e.g.,
P2) receptors (Ralevic et al., "Receptors for Purines and
Pyrimidines", Pharmacological Reviews, Vol. 50, No. 3); CNS
receptors and membrane transporters (E. Sylvester Vizi, "Role of
High-Affinity Receptors and Membrane Transporters in Nonsynaptic
Communication and Drug Action in the Central Nervous
System,"Pharmacological Reviews, Vol. 52, No. 1);
[0568] Opoid receptors, including but not limited to the 6-opioid
receptor (Quock et al., "The .delta.-Opioid Receptor: Molecular
Pharmacology, Signal Transduction and the Determination of Drug
Efficacy", Pharmacological Review, Col. 51, No. 3);
[0569] Angiotensin II receptors (Gasparo et al., "International
Union of Pharmacology. XXIII. The Angiotensin II Receptors"
Pharmalogical Review, Vol. 52, No. 3);
[0570] Cholecystokinin receptors (Noble et al., "International
Union of Pharmacology. XXI. Structure, Distribution, and Functions
of Cholecystokinin Receptors", Pharmacological Reviews, Vol. 51,
No. 4)
[0571] Hormone receptors, including but not limited to, the
estrogen receptor; the glucocorticoid receptor; and the insulin
receptor;
[0572] Receptors found predominantly in the central nervous system,
including but not limited to, neuronal nicotinic acetylcholine
receptors; the dopamine D2/D3 receptor; GABA receptors; central
cannabinoid receptor CB1; opoid receptors, e.g., the kappa opioid
receptor, and the methadone-specific opioid receptor; nicotinic
acetylcholine receptors; serotonin receptors, e.g., the serotonin
5-HT3 receptor, the serotonin 5-HT4 receptor, and the serotonin-2
receptor; and dopamine receptors, e.g., the dopamine D2/D3
receptor; and the neurotensin receptor;
[0573] Receptors for growth factors, including but not limited to,
the erythropoietin receptor; the FGF receptor; the EGF receptor;
the VEGF receptor; VEGF receptor-2 protein; VEGF-receptor protein
(KDR); fibroblast growth factor receptor; the p75 nerve growth
factor receptor; epidermal growth factor receptor; IGF-1 receptor;
platelet factor-4 receptor; alpha platelet-derived growth factor
receptor; hepatocyte growth factor receptor; and human fibroblast
growth factor receptor;
[0574] Receptors for sphingolipids and lysophospholipids such as
the Edg family of GPCRs;
[0575] Receptors for interleukins, e.g., receptors for
interleukin-1 (IL-1), IL-2, IL-3, IL-4, IL-5, IL-6, IL-7, IL-8,
IL-9, IL-10, IL-11, IL-12, IL-13, et seq.; and Various receptors,
including by way of non-limiting example, receptors described in
U.S. pat. No. 6,210,967 (DNA encoding a mammalian LPA receptor and
uses thereof); U.S. Pat. No. 6,210,921 (CAR: a novel coxsackievirus
and adenovirus receptor; U.S. Pat. No. 6,211,343 (Lactoferrin
receptor protein; U.S. Pat. No. 6,218,509 (LH/CG receptor, DNA and
use thereof; U.S. Pat. No. 6,214,972 (DNA encoding prostaglandin
receptor DP); U.S. Pat. No. 6,221,613 (DNA encoding a human melanin
concentrating hormone receptor (MCH1) and uses thereof); U.S. Pat.
No. 6,221,660 (DNA encoding SNORF25 receptor); U.S. Pat. No.
6,225,080 (Mu-subtype opioid receptor); U.S. Pat. No. 6,222,015
(Estrogen receptor); U.S. Pat. No. 6,228,610 (Human metabotropic
glutamate receptor subtypes (hmR4, hmR6, hmR7) and related DNA
compounds); U.S. Pat. No. 6,235,496 (Nucleic acid encoding
mammalian mu opioid receptor); U.S. Pat. No. 6,258,556 (cDNA and
genomic clones encoding human mu. opiate receptor and the purified
gene product); U.S. Pat. No. 6,245,531 (Polynucleotide encoding
insect ecdysone receptor); U.S. Pat. No. 6,225,531 Glucan elicitor
receptor, DNA molecule coding therefor, fungus-resistant plants
transformed with the DNA molecule and method for creating the
plants); U.S. Pat. No. 6,245,893 (Receptor that binds
anti-convulsant compounds); U.S. Pat. No. 6,248,712 (Urokinase-type
plasminogen activator receptor; U.S. Pat. No. 6,248,554 (DNA
sequence coding for a BMP receptor); U.S. Pat. No. 6,248,520
(Nucleic acid molecules encoding nuclear hormone receptor
coactivators and uses thereof); U.S. Pat. No. 6,242,251 (Rhesus
neuropeptide Y5 receptor); U.S. Pat. No. 6,252,056 (Human
lysophosphatidic acid receptor and use thereof); U.S. Pat. No.
6,255,472 (Isolated nucleic acid molecule encoding a human skeletal
muscle-specific receptor); U.S. Pat. No. 6,291,207 (Herpes virus
entry receptor protein); U.S. Pat. No. 6,291,206 (BMP receptor
proteins); U.S. Pat. No. 6,291,195 (DNA encoding a human melanin
concentrating hormone receptor (MCH1) and uses thereof); U.S. Pat.
No. 6,344,200 (Lactoferrin receptor protein); U.S. Pat. No.
6,335,180 (Nucleic acid sequences encoding capsaicin receptor and
uses thereof); U.S. Pat. No. 6,265,184 (Polynucleotides encoding
chemokine receptor 88C); U.S. Pat. No. 6,207,799 (Neuropeptide Y
receptor Y5 and nucleic acid sequences); U.S. Pat. No. 6,290,970
(Transferrin receptor protein of Moraxella); U.S. Pat. No.
6,326,350 (Transferrin receptor subunit proteins of Neisseria
meningitidis); U.S. Pat. No. 6,313,279 (Human glutamate receptor
and related DNA compounds); U.S. Pat. No. 6,313,276 (Human
endothelin receptor); U.S. Pat. No. 6,307,030 (Androgen receptor
proteins, recombinant DNA molecules coding for such, and use of
such compositions); U.S. Pat. No. 6,306,622 (cDNA encoding a BMP
type II receptor); U.S. Pat. No. 6,300,087 (DNA encoding a human
serotonin receptor (5-HT4B) and uses thereof); U.S. Pat. No.
6,297,026 (Nucleic acids encoding the C140 receptor); U.S. Pat. No.
6,277,976 (Or-1, an orphan receptor belonging to the nuclear
receptor family); U.S. Pat. No. 6,274,708 (Mouse interleukin-11
receptor); U.S. Pat. No. 6,271,347 (Eosinophil eotaxin receptor);
U.S. Pat. No. 6,262,016 (Transferrin receptor genes); U.S. Pat. No.
6,261,838 (Rat melanocortin receptor MC3-R); U.S. Pat. No.
6,258,943 (Human neurokinin-3 receptor); U.S. Pat. No. 6,284,870
(Gamma retinoic acid receptor); U.S. Pat. No. 6,258,944 (OB
receptor isoforms and nucleic acids encoding them); U.S. Pat. No.
6,261,801 (Nucleic acids encoding tumor necrosis factor receptor
5); U.S. Pat. No. 6,261,800 (Luteinizing hormone/choriogonadotropin
(LH/CG) receptor); U.S. Pat. No. 6,265,563 (Opioid receptor genes);
U.S. Pat. No. 6,268,477 (Chemokine receptor 88-C); U.S. Pat. No.
6,316,611 (Human N-methyl-D-aspartate receptor subunits, nucleic
acids encoding same and uses therefor); U.S. Pat. No. 6,316,604
(Human C3b/C4b receptor (CR1)); U.S. Pat. No. 6,287,855 (Nucleic
acid encoding rat galanin receptor (GALR2)); U.S. Pat. No.
6,268,221 (Melanocyte stimulating hormone receptor and uses); and
U.S. Pat. No. 6,268,214 (Vectors encoding a modified low affinity
nerve growth factor receptor).
[0576] X.A.3. Other Membrane Proteins
[0577] Other membrane proteins are within the scope of the
invention and include but are not limited to channels (e.g.,
potassium channels, sodium channels, calcium channels.), pores
(e.g., nuclear pore proteins, water channels), ion and other pumps
(e.g., calcium pumps, proton pumps), exchangers (e.g.,
sodium/potassium exchangers, sodium/hydrogen exchangers,
potassium/hydrogen exchangers), electron transport proteins (e.g.,
cytochrome oxidase), enzymes and kinases (e.g., protein kinases,
ATPases, GTPases, phosphatases, proteases.), structural/linker
proteins (e.g., Caveolins, clathrin), adapter proteins (e.g., TRAD,
TRAP, FAN),
[0578] X.A.3.a. Cellular Adhesion Molecules
[0579] Cellular adhesion molecules, including but not limited to
human rhinovirus receptor (ICAM-1), ICAM-2, ICAM-3, and PECAM-1,
and chemotactic/adhesion proteins (e.g., ,selectins, CD34, VCAM-1,
LFA-1,VLA-1) are within the scope of the invention. See also Alpin
et al., "Signal Transduction and Signal Modulation by Cell Adhesion
Receptors: The Role of Integrins, Cadherins, Immunoglobulin-Cell
Adhesion Molecules, and Selectins", Pharmacological Reviews, Vol.
50, No. 2.
[0580] X.A.3.b. Cytochrome P450 Enzymes
[0581] The family of enzymes known as "cytochrome P450" enzymes
(since they absorb light in the 450 nanometer range), or as
"cytochrome oxidase" enzymes (since they oxidize a wide range of
compounds that do not naturally occur in circulating blood), are
included within the scope of the invention. P450 enzymes
encompasses a variety of enzymes, many of which are involved in
xenobiotic metabolism, including by way of non-limiting example the
metabolism of drugs, prodrugs and toxins. Directories and databases
of P450s, and information regarding their substrates, are available
on-line (Fabian et al., The Directory of P450-containing Systems in
1996, Nucleic Acids Research 25:274-277, 1997). In humans, at least
about 200 different P450s are present (for a review, see Hasler et
al., Human cytochromes P450, Molecular Aspects of Medicine
20:1-137, 1999). There are multiple forms of these P450s and each
of the individual forms exhibit degrees of specificity towards
individual compounds or sets of compounds. In some cases, a
substrate, whether it is a drug or a carcinogen, is metabolized by
more than one cytochrome P450.
[0582] Members of the cytochrome P450 family are present in varying
levels and their expression and activities are controlled by
variables such as chemical environment, sex, developmental stage,
nutrition and age. The cytochrome P450s are found at high
concentrations in liver cells, and at lower concentrations in other
organs and tissues such as the lungs (e.g., Fonne-Pfister et al.,
Xenobiotic and endobiotic inhibitors of cytochrome P-450dbl
function, the target of the debrisoquine/sparteine type
polymorphism, Biochem. Pharmacol. 37:3829-35, 1988). By oxidizing
lipophilic compounds, which makes them more water-soluble,
cytochrome oxidase enzymes help the body eliminate (via urine, or
in aerosols exhaled out of the lungs) compounds that might
otherwise act as toxins or accumulate to undesired levels.
[0583] In humans, several cytochrome P450s have been identified as
being involved in xenobiotic metabolism. These include CYP1A1,
CYP1A2, CYP2A6, CYP2B6, CYP2C8, CYP2C9, CYP2C18, CYP2C19, CYP2D6,
CYP2E1, CYP3A4, and CYP3A5 (Crespi et al., The use of heterologous
expressed drug metabolizing enzymes-state of the art and prospects
for the future, Pharm Ther 84:121-131, 1999).
[0584] X.A.3.c. Miscellaneous Membrane Proteins
[0585] In addition to the preceding non-limiting examples, the
invention can be applied to the membrane proteins described in U.S.
Pat. No. 6,335,018 (High molecular weight major outer membrane
protein of moraxella); U.S. Pat. No. 6,264,954 (Haemophilus outer
membrane protein); U.S. Pat. No. 6,197,543 (Human vesicle membrane
protein-like proteins); U.S. Pat. No. 6,121,427 (Major outer
membrane protein CD of branhamella); U.S. Pat. No. 6,083,743 and
U.S. Pat. No. 6,013,514 (Haemophilus outer membrane protein); U.S.
Pat. No. 6,004,562 (Outer membrane protein B1 of Moraxella
catarrhalis); U.S. Pat. No. 5,863,764 (DNA encoding a human
membrane protein); U.S. Pat. No. 5,861,283 (DNA encoding a limbic
system-associated membrane protein); U.S. Pat. No. 5,824,321
(Cloned leptospira outer membrane protein); U.S. Pat. No. 5,821,085
(Nucleotide sequences of a T. pallidum rare outer membrane
protein); U.S. Pat. No. 5,821,055 (Chlamydia major outer membrane
protein); U.S. Pat. No. 5,808,024 (Nucleic acids encoding high
molecular weight major outer membrane protein of moraxella); U.S.
Pat. No. 5,770,714 (Chlamydia major outer membrane protein); U.S.
Pat. No. 5,763,589 (Human membrane protein); U.S. Pat. No.
5,753,459 (Nucleotide sequences of T. pallidum rare outer membrane
protein); U.S. Pat. No. 5,607,920 (Concanavalin a binding proteins
and a 76 kD chondrocyte membrane protein (CMP) from chondrocytes
and methods for obtaining same); and U.S. Pat. No. 5,503,992 (DNA
encoding the 15 kD outer membrane protein of Haemophilus
influenzae).
[0586] X.B. Membrane Anchoring Domains
[0587] A membrane-anchoring domain can be incorporated into a
fusion protein of the invention. Non-limiting examples of membrane
anchoring domains include those derived from Prostaglandin H2
synthases (PGHS-1 and -2) (Nina et al., Anchoring of a monotopic
membrane protein: the binding of prostaglandin H2 synthase-1 to the
surface of a phospholipid bilayer, Eur. Biophys. J. 29:439-54,
2000; Otto and Smith, Photolabeling of prostaglandin endoperoxide H
synthase-1 with 3-trifluoro-3-(m-[125I]iodop- henyl)diazirine as a
probe of membrane association and the cyclooxygenase active site, J
Biol Chem 271:9906-10, 1996; and Otto and Smith, The orientation of
prostaglandin endoperoxide synthases-1 and -2 in the endoplasmic
reticulum, J Biol Chem 269:19868-75, 1994; those derived from
carboxypeptidase E (EC 3.4.17.10) (Fricker et al., Identification
of the pH-dependent membrane anchor of carboxypeptidase E (EC
3.4.17.10), J. Biol. Chem., 265, 2476-2482, 1990); and peptide
convertase 3 (PC3) (Smeekens et al., Identification of a cDNA
encoding a second putative prohormone convertase related to PC2 in
AtT20 cells and islets of Langerhans, Proc Natl Acad Sci USA 88,
340-344, 1990).
[0588] X.C. Transmembrane Domains
[0589] A variety of types and examples of transmembrane domain are
known. Proteins with up to 12 transmembrane domains are known
(Fujiwara et al., Identification of thyroid hormone transporters in
humans: different molecules are involved in a tissue-specific
manner, Endocrinology 2001 142:2005-12; Sharina et al., Mutational
analysis of the functional role of conserved arginine and lysine
residues in transmembrane domains of the murine reduced folate
carrier, Mol Pharmacol 2001 59:1022-8). However, the invention is
not limited to any particular number of transmembrane domains.
[0590] Monotropic ("single pass") domains, which traverse a
membrane once, include by way of non-limiting example, those found
in receptors for epidermal growth factor (EGF), receptors for tumor
necrosis factor (TNF) and the like. Polytropic ("multipass")
proteins traverse a membrane two or more times. Non-limiting
examples of polytropic proteins are as follows.
[0591] Biotropic ("2 passes") membrane proteins include, but are
not limited to: EnvZ of E. coli; the peroxisomal membrane protein
Pex11-1p (Anton et al., ARF- and coatomer-mediated peroxisomal
vesiculation, Cell Biochem Biophys 2000;32 Spring:27-36);
pleitropic drug ABC transporters of S. cervisiae (Rogers et al.,
The pleitropic drug ABC transporters from Saccharomyces cerevisiae,
J Mol Microbiol Biotechnol 2001 3:207-14); and human and rate urate
transporters hUAT and rUAT (Lipkowitz et al., Functional
reconstitution, membrane targeting, genomic structure, and
chromosomal localization of a human urate transporter, J Clin
Invest 2001 107:1103-15).
[0592] Tritropic ("3 pass") membrane proteins include, but are not
limited to: the ethylene receptor ETRI of Arabidopsis; the
Cauliflower Card Expression protein CC1 (Palmer et al., A Brassica
oleracea Gene Expressed in a Variety-Specific Manner May Encode a
Novel Plant Transmembrane Receptor, Plant Cell Physiol 2001
42:404-413); and a splice variant of the mitochondrial membrane
protein hMRS3/4 (Li et al., Characterization of a novel human
putative mitochondrial transporter homologous to the yeast
mitochondrial RNA splicing proteins 3 and 4, FEBS Lett 2001
494:79-84).
[0593] Tetraspanins or tetraspans are non-limiting examples of
membrane proteins with four transmembrane domains. (Levy et al., J.
Biol. Chem, 226:14597-14602, 1991; Tomlinson et al., J. Immol.
23:136-40, 1993; and Barclay et al., (In) The Leucocyte antigen
factbooks, Academic press, London, 1993). These proteins are
collectively known as the `transmembrane 4 superfamily` (TM4)
because they span the plasma membrane four times. The proteins
known to belong to this family include, but are not limited to:
mammalian antigen CD9 (MIC3), a protein involved in platelet
activation and aggregation; mammalian leukocyte antigen CD37,
expressed on B lymphocytes; mammalian leukocyte antigen CD53
(OX-44), which may be involved in growth regulation in
hematopoietic cells; mammalian lysosomal membrane protein CD63
(Melanoma-associated antigen ME491; antigen AD1); mammalian antigen
CD81 (cell surface protein TAPA-1), which may play an important
role in the regulation of lymphoma cell growth; mammalian antigen
CD82 (Protein R2; Antigen C33; Kangai 1 (KAI1)), which associates
with CD4 or CD8 and delivers costimulatory signals for the TCR/CD3
pathway; mammalian antigen CD151 (SFA-1); Platelet-endothelial
tetraspan antigen 3 (PETA-3); mammalian TM4SF2 (Cell surface
glycoprotein A15; TALLA-1; MXS1); mammalian TM4SF3
(Tumor-associated antigen CO-029); mammalian TM4SF6 (Tspan-6;
TM4-D); mammalian TM4SF7 (Novel antigen 2 (NAG-2); Tspan-4);
mammalian Tspan-2; Mammalian Tspan-3 (TM4-A); mammalian Tetraspan
NET-5; and Schistosoma mansoni and japonicum 23 Kd surface antigen
(SM23/SJ23).
[0594] Non-limiting examples of membrane proteins with six
transmembrane domains include the EBV integral membrane protein
LMP-1, and a splice variant of the mitochondrial protein hMRS3/4
(Li et al., Characterization of a novel human putative
mitochondrial transporter homologous to the yeast mitochondrial RNA
splicing proteins 3 and 4, FEBS Lett Apr. 6, 2001;494(1-2):79-84).
Proteins wit six transmembrane domains also include STEAP (six
transmembrane epithelial antigens of the prostate) proteins (Afar
et al., U.S. Pat. No. 6,329,503). The prototype member of the STEAP
family, STEAP-1, appears to be a type IIIa membrane protein
expressed predominantly in prostate cells in normal human tissues.
Structurally, STEAP-1 is a 339 amino acid protein characterized by
a molecular topology of six transmembrane domains and intracellular
N- and C-termini, suggesting that it folds in a "serpentine" manner
into three extracellular and two intracellular loops.
[0595] Literally hundreds of 7-pass membrane proteins are known.
G-protein coupled receptors (GPCRs), including without limitation
beta-adreno receptors, adrenergic receptors, EDG receptors,
adenosine receptors, B receptors for kinins, angiotensin receptors,
and opiod receptors are of particular interest. GPCRs are described
in more detail elsewhere herein.
[0596] A non-limiting example of a protein with 9 transmembrane
domains is Lipocalin-1 interacting membrane receptor (Wojnar et
al., Molecular cloning of a novel Lipocalin-1 interacting human
cell membrane receptor (LIMR) using phage-display, J Biol Chem 2001
3; [epub ahead of print]).
[0597] Proteins with both transmembrane and anchoring domains are
known. For example, AMPA receptor subunits have transmembrane
domains and one membrane-anchoring domain.
[0598] A variety of databases that describe known, and software
programs that predict, membrane anchoring and transmembrane domains
are available to those skilled in the art. See, for example
Gcrdb.dba GCRDb [G Protein Coupled Receptor database], Tmbase.dba
Tmbase [database of transmembrane domains], Prodom.srv ProDom
[Protein domains], Tmap.srv TMAP [Protein transmembrane segments
prediction], Tm7.srv TM7 [Retrieval of data on G protein-coupled
receptors], and Memsat.sof MEMSAT [transmembrane structure
prediction program].
[0599] Quentin and Fichant (J Mol Microbiol Biotechnol 2000
2:501-4, ABCdb: an ABC transporter database) have described a
database devoted to the ATP-binding cassette (ABC) protein domains
(ABCdb), the majority of which energize the transport of compounds
across membranes. In bacteria, ABC transporters are involved in the
uptake of a wide range of molecules and in mechanisms of virulence
and antibiotic resistance. In eukaryotes, most ABC transporters are
involved in drug resistance, and many are associated with diseases.
ABCdb can be accessed via the World Wide Web
(http://ir21cb.cnrs-mrs.fr/ABCdb/). See also Sanchez-Fernandez et
al., The Arabidopsis thaliana ABC protein superfamily: a complete
inventory, J Biol Chem may 9, 2001[epub ahead of print], and Rogers
et al., The pleitropic drug ABC transporters from Saccharomyces
cerevisiae, J Mol Microbiol Biotechnol 2001 April;3(2):207-14.
[0600] X.D. Functions and Activities of Membrane Proteins
[0601] Non-limiting examples of membrane proteins include
membrane-associated enzymes. Membrane-associated enzymes include
but not limited to certain enzymes of the electron transport chain
(ETC), antigenic proteins such as the major histocompatability
(MHC) antigens, transport proteins, channels, hormone receptors,
cytokine receptors, glucose permeases, gap junction proteins and
bacteriorhodopsins.
[0602] A "transport protein" or "transporter" is a type of membrane
protein that allows substances to cross plasma membranes at a rate
that is faster than what is found by diffusion alone. Some
transport proteins expend energy to move substances (active
transport). Many active transport proteins are ATPases (e.g., the
Na.sup.+-K.sup.+ATPase), or at least bind ATP by virtue of
comprising an ATP-binding cassette (ABC) (see, e.g., Rogers et al.,
The pleitropic drug ABC transporters from Saccharomyces cerevisiae,
J Mol Microbiol Biotechnol 3:207-14, 2001). Nucleobase transporters
are reviewed by De Koning and Diallinas (Nucleobase Transporters,
Mol Membr Biol 17:75-94, 2000).
[0603] A "channel protein" is a protein that facilitates the
diffusion of molecules/ions across lipid membranes by forming a
hydrophilic pore or "channel" that provides molecules/ions access
through lipid membranes, which are generally hydrophobic. Channels
are often multimeric, with the pore being formed by subunit-subunit
interactions.
[0604] A "receptor" is a molecular entity, typically a protein,
that is displayed on the surface of a cell. A receptor is
characterized by high affinity, often a specific binding of a
specific substance, typically resulting in a specific biochemical
or physiological effect.
[0605] A "hormone" is a naturally occurring substance secreted by
specialized cells that affects the metabolism or behavior of other
cells having receptors for the hormone. Non-limiting examples of
hormones having receptors include but are not limited to insulin,
cytokines, steroid hormones, histamines, glucagon, angiotensin,
catecholamines, low density lipids (LDLs), tumor necrosis factor
alpha, tumor necrosis factor beta, estrogen, and testosterone.
[0606] X. E. G-Protein-Coupled Receptors
[0607] G protein-coupled receptors (GPCRs) constitute the most
prominent family of validated drug targets within biomedical
research and are thought to be involved in such diseases and
disorders as heart disease, hypertension, cancer, obesiy, and
depression and other mental illnesses. Over half of approved drugs
elicit their therapeutic effects by selectively addressing members
of this target family and more than 1000 sequences of the human
genome encode for GPCRs containing the classical 7-pass membrane
structure characteristic of this family of proteins (Marinissen, M.
and J. S. Gutkind, G-protein-coupled receptors and signaling
networks: emerging paradigms (Review), Trends. Phamacol. Sci. 22:
368-376, 2001). Many pharmacological drug companies are interested
in the study of G-coupled proteins. It is possible to co-express a
G-coupled protein receptor and its associated G-protein to study
their pharmacological characteristics (Strosberg and Marullo,
Functional expression of receptors in microorganisms. TiPS, 1992.
13: 95-98).
[0608] G-protein-coupled receptors (GPCRs) are reviewed by
Marinissen, M. and J. S. Gutkind, G-prolien-coupled receptors and
signaling networks: emerging paradigms. Trends. Phamacol. Sci. 22:
368-376, 2001; Sautel and Milligan, Molecular manipulation of
G-protein-coupled receptors: a new avenue into drug discovery, Curr
Med Chem 2000 889-96; Hibert et al., This is not a G
protein-coupled receptor, Trends Pharmacol Sci 1993, 14:7-12;
Wilson et al., Orphan G-protein-coupled receptors: the next
generation of drug targets?, Br J Pharmacol 1998, 125:1387-92; Roth
et al., G protein-coupled receptor (GPCR) trafficking in the
central nervous system: relevance for drugs of abuse, Drug Alcohol
Depend 1998, 51:73-85; Ferguson and Caron, G protein-coupled
receptor adaptation mechanisms, Semin Cell Dev Biol 1998, 9:119-27;
Wank, G protein-coupled receptors in gastrointestinal physiology.
I. CCK receptors: an exemplary family, Am J Physiol 1998,
274:G607-13; Rohrer and Kobilka , G protein-coupled receptors:
functional and mechanistic insights through altered gene
expression. (Review), Physiol Rev 1998, 78:35-52; and Larhammar et
al., The receptor revolution--multiplicity of G-protein-coupled
receptors. (Review), Drug Des Discov 1993, 9:179-88.
[0609] GPCR localization and regulation has been studied using
GFP-comprising fusion proteins (Kallal and Benovic, Using green
fluorescent proteins to study G-protein-coupled receptor
localization and trafficking. (Review), Trends Pharmacol Sci 2000
21:175-80; and Ferguson, Using green fluorescent protein to
understand the mechanisms of G-protein-coupled receptor regulation.
(Review), Braz J Med Biol Res 1998, 31:1471-7); and by using
chimeric GPCRs (Milligan and Rees, Chimaeric G alpha proteins:
their potential use in drug discovery. (Review), Erratum in: Trends
Pharmacol Sci 1999 Jun; 20(6):252.
[0610] GPCRs belong to a superfamily of at least 6 families of
receptors, the most important of which is the main family, A.
Members of the membrane protein gene superfamily of GPCRs have been
characterized as having seven putative transmembrane domains. The
transmembrane domains are believed to represent transmembrane
alpha-helices connected by extracellular or cytoplasmic loops. A
functional G-protein is a trimer which consists of a variable alpha
subunit coupled to much more tightly-associated and constant beta
and gamma subunits, although G-protein independent actions have
been postulated (Marinissen, M. and J. S. Gutkind,
G-protien-coupled receptors and signaling networks: emerging
paradigms. Trends. Phamacol. Sci. 22: 368-376, 2001 Review). A
variety of ligands have been identified which function through
GPCRs. In general, binding of an appropriate ligand (e.g.,
bioactive lipids, ions, bioactive amines, photons, odorants,
hormones, neurotransmitters, peptides, nucleosides, etc.) to a GPCR
leads to the activation of the receptor. G-protein coupled
receptors include a wide range of biologically active receptors,
such as hormone, viral, growth factor and neuroreceptors.
Typically, activation of a GPCR initiates the regulatory cycle of a
corresponding G-protein. This cycle consists of GTP exchange for
GDP, dissociation of the alpha and beta/gamma subunits, activation
of the second messenger pathway by a complex of GTP and the alpha
subunit of the G-protein, and return to the resting state by GTP
hydrolysis via the innate GTPase activity of the G-protein alpha
subunit A.
[0611] GPCRs include, without limitation, dopamine receptors which
bind to neuroleptic drugs used for treating psychotic and
neurological disorders. Other examples of members of this family
include calcitonin, adrenergic, endothelin, cAMP, adenosine,
muscarinic, acetylcholine, serotonin, histamine, thrombin, kinin,
follicle stimulating hormone, opsins and rhodopsins, odorant,
cytomegalovirus receptors, and the like.
[0612] Most GPCRs have single conserved cysteine residues in each
of the first two extracellular loops which form disulfide bonds
that are believed to stabilize functional protein structure. The
seven transmembrane regions, each comprising conserved hydrophobic
stretches of about 20 to 30 amino acids, are designated as TM1,
TM2, TM3, TM4, TM5, TM6, and TM7. TM3 is also implicated in signal
transduction.
[0613] Although not wishing to be bound by any particular theory,
it is believed that GPCRs participate in cell signaling through
their interactions with heterotrimetric G-proteins composed of
alpha, beta and gamma subunits (Marinissen, M. and J. S. Gutkind,
G-protien-coupled receptors and signaling networks: emerging
paradigms. Trends. Phamacol. Sci. 22:368-376, 2001). In some
aspects of the invention, GPCRs and homologs are displayed on the
surfaces of minicells.
[0614] X.F. EDG Receptors and Other Sphingolipid-Binding
Receptors
[0615] The Endothelial Differentiation Gene (EDG) receptor family
includes but is not limited to eight presently known GPCRs that
have a high affinity to lipid ligands (Lynch et al., Life on the
edg. Trends Pharmacol. Sci., 1999. 20: 273-5). These transmembrane
receptors are found in several different tissues in different
species. EDG receptors have been shown to be involved in calcium
mobilization, activation of mitogen-activated protein kinase,
inhibition of adenylate cyclase activation, and alterations of the
cytoskelaton. The EDG family is divided into two different groups
based on homology and ligand specificity. The EDG 2, 4, and 7
receptors are specific for the ligand lysophosphatidic acid (LPA)
(An et al., Signaling Mechanism and molecular characteristics of G
protein-coupled receptors for lysophosphatidic acid and sphingosine
1-phosphate. J. Cell Biochem, 30/31:147-157, 1998; Goetzl et al.,
Distinctive expression and functions of the type 4 endothelial
differentiation gene-encoded G protein-coupled receptor for
lysophosphatidic acid in ovarian cancer. Cancer Res., 59:5370-5,
1999). In contrast, EDG 1, 3, and 5 bind sphingosine-1-phosphate
(S1P) (Zhang et al., Comparative analysis of three murine G-protein
coupled receptors activated by sphingosine-1-phosphate. Gene,
227:89-99, 1999). EDG -6 is believed to interact with SIP (Yamazaki
et al., Edg-6 as a putative sphingosine 1-phosphate receptor
coupling to Ca2.sup.++ signaling pathway. Biochem Phys Res Com,
268:583-589, 2000).
[0616] Receptors that bind S1P and other sphingolipids are used in
one aspect of the invention (for a review of some S1P-binding
receptors, see Spiegel et al., Biochim. Biophys. Acta 1484:107-116,
2000). Such receptors include but are not limited to members of the
EDG family of receptors (a.k.a. 1pA receptors, Chun, Crit. Rev.
Neuro. 13:151-168, 1999), and isoforms and homologs thereof such as
NRG1 and AGR16.
[0617] EDG-1 was the first identified member of a class of G
protein-coupled endothelial-derived receptors (EDG). Non-limiting
examples of other EDG family members that also bind SIP include
EDG-3 (a.k.a. ARG16; the rat homolog of EDG-3 is designated H218),
EDG-5 , EDG-6 and EDG-8. For reviews, see Goetzl et al., Adv. Exp.
Med. Biol. 469:259-264, 1999; and Chun et al., Cell. Biochem.
Biophys. 30:213-242, 1999).
[0618] EDG-1 is described by Lee et al., (Ann. NY Acad. Sci.
845:19-31, 1998). Liu and Hla, The mouse gene for the inducible
G-Protein-coupled receptor edg-1. Genomics, 1997, 43: p. 15-24.
Human EDG-1c genes and proteins are described in published PCT
application WO 99/46277 to Bergsma et al.
[0619] EDG-3 is described by Okamoto et al. (Biochem. Biophys. Res.
Commun. 260:203-208, 1999) and An et al. (FEBS Letts. 417:279-282,
1997). See also An et al., J. Biol. Chem. 275:288-296, 2000.
[0620] EDG-5 human and mammalian genes are described in U.S. Pat.
No. 6,057,126 to Munroe et al. and published PCT application WO
99/33972 to Munroe et al. The rat homolog, H218, is described in
U.S. Pat. No. 5,585,476 to MacLennan et al. Van Brocklyn et al., J.
Biol. Chem. 274:4626-4632, 1999; and Gonda et al., Biochem. J.
337:67-75, 1999. See also An et al., J. Biol. Chem. 275:288-296,
2000.
[0621] EDG-6 is described by Graler et al. (Genomics 53:164-169,
1998), Yamazaki et al. (Biochem. Biophys. Res. Commun. 268:583-589,
2000), and Van Brocklyn et al. (Sphingosine-1-phosphate is a ligand
for the G protein-coupled receptor EDG-6, Blood 95:2624-9,
2000).
[0622] EDG-8 from rat brain is described by Im et al., (J. Biol.
Chem. 275:14281-14286, 2000). Homologs of EDG-8 from other species,
including humans, may also be used in the present invention.
[0623] The Mil receptor (Mil is an abbreviation for "miles apart")
binds S1P and regulates cell migration during vertebrate heart
development. The Mil receptor of Zebrafish is described by Mohler
et al. (J. Immunol. 151:1548-1561, 1993). Another S1P receptor is
NRG1 (nerve growth factor regulated gene-1), the rat version of
which has been identified (Glickman et al., Mol. Cel. Neurosci.
14:141-152, 1999).
[0624] Receptors that bind sphingosylphosphoryl choline (SPC) are
also used in this aspect of the invention. Such receptors include
but are not limited to members of the SCaMPER family of receptors
(Mao et al., Proc. Natl. Acad. Sci. U.S.A. 93:1993-1996, 1996;
Betto et al., Biochem. J. 322:327-333, 1997). Some evidence
suggests that EDG-3 may bind SPC in addition to S1P (Okamoto et
al., Biochem. Biophys. Res. Commun. 260:203-208, 1999). Derivatives
of EDG-3 that bind both S1P and SPC are used in one aspect of the
invention.
[0625] Receptors that bind lysophophatidic acid may be used in the
present invention. These include EDG-2 (LPA1), EDG-4 (LPA2), EDG-7
(LPA3). See Moller et al., Expression and function of
lysophosphatidic acid receptors in cultured rodent microglial
cells, J Biol Chem 2001 May 4 [epub ahead of print]; Fukushima and
Chun, The LPA receptors, Prostaglandins 64(1-4):21-32, 2001; Contos
and Chun, The mouse 1p(A3)/Edg7 lysophosphatidic acid receptor
gene: genomic structure, chromosomal localization, and expression
pattern, Gene 267:243-53, 2001; Schulte et al., Lysophosphatidic
acid, a novel lipid growth factor for human thyroid cells:
over-expression of the high-affinity receptor edg4 in
differentiated thyroid cancer, Int J Cancer 92249-56, 2001; Kimura
et al., Two novel Xenopus homologs of mammalian LP(A1)/EDG-2
function as lysophosphatidic acid receptors in Xenopus oocytes and
mammalian cells, J Biol Chem 276:15208-15, 2001; and Swarthout and
Walling, Lysophosphatidic acid: receptors, signaling and survival
(Review), Cell Mol Life Sci 57:1978-85, 2000.
[0626] Examples of lysophospholipid receptors including, but not
limited to EDG proteins, are disclosed in Fukushima et al.
(Lysophospholipid receptors. Annu. Rev. Pharmacol. Toxicol.
41:507-534, 2001) Malek and Lee (Nrg-1 Belongs to the Endothelial
Differentiation Gene Family of G Protein-coupled
Sphingosine-1-phosphate Receptors, J. Biol. Chem. 276:5692-5699,
2001), Hla et al. (Sphingosine-1-phosphate signaling via the EDG-1
family of G-protein-coupled receptors (Review), Ann N Y Acad Sci
905:16-24, 2000; Chun, Lysophospholipid receptors: implications for
neural signaling (Review), Crit Rev Neurobiol 13:151-68, 1999); and
Chun et al. (A growing family of receptor genes for
lysophosphatidic acid (LPA) and other lysophospholipids (LPs)
(Review), Cell Biochem Biophys 30:213-42, 1999).
XI. Recombinant DNA Expression
[0627] In order to achieve recombinant expression of a fusion
protein, an expression cassette or construct capable of expressing
a chimeric reading frame is introduced into an appropriate host
cell to generate an expression system. The expression cassettes and
constructs of the invention may be introduced into a recipient
eubacterial or eukaryotic cell either as a nonreplicating DNA or
RNA molecule, which may be a linear molecule or, more preferably, a
closed covalent circular molecule. Since such molecules are
incapable of autonomous replication, the expression of the gene may
occur through the transient expression of the introduced sequence.
Alternatively, permanent expression may occur through the
integration of the introduced DNA sequence into the host
chromosome.
[0628] XI.A. Recombinant DNA Expression Systems
[0629] A variety of eubacterial recombinant DNA expression systems
may be used to produce the fusion proteins of the invention. Host
cells that may be used in the expression systems of the present
invention are not strictly limited, provided that they are suitable
for use in the expression of the fusion protein of interest and can
produce minicells. Non-limiting examples of recognized eubacterial
hosts that may be used in the present invention include bacteria
such as E. coli, Bacillus, Streptomyces, Pseudomonas, Salmonella,
Serratia, and the like.
[0630] Eubacterial expression systems utilize plasmid and viral
(bacteriophage) expression vectors that contain replication sites
and control sequences derived from a species compatible with the
host may be used. Suitable phage or bacteriophage vectors include
.lambda.gt10, .lambda.gt11 and the like. Suitable virus vectors may
include pMAM-neo, pKRC and the like. Appropriate eubacterial
plasmid vectors include those capable of replication in E. coli
(such as, by way of non-limiting example, pBR322, pUC118, pUC119,
ColE1, pSC101, pACYC 184, .pi.VX. See "Molecular Cloning: A
Laboratory Manual" 1989). Bacillus plasmids include pC194, pC221,
pT127, and the like (Gryczan, In: The Molecular Biology of the
Bacilli, Academic Press, NY, pp. 307-329, 1982). Suitable
Streptomyces plasmids include p1J101 (Kendall et al., J. Bacteriol.
169:4177-4183, 1987), and Streptomyces bacteriophages such as C31
(Chater et al., In: Sixth International Symposium on
Actinomycetales Biology, Akademiai Kaido, Budapest, Hungary, pp.
45-54, 1986). Pseudomonas plasmids are reviewed by John et al.
(Rev. Infect. Dis. 8:693-704, 1986), and Izaki (Jpn. J. Bacteriol.
33:729-742, 1978). See also Brent et al., "Vectors Derived From
Plasmids," Section II, and Lech et al. "Vectors derived from Lambda
and Related Bacteriophages" Section III, in Chapter 1 of Short
Protocols in Molecular Biology, 2nd Ed., Ausubel et al., eds., John
Wiley and Sons, New York, 1992, pages 1-13 to 1-27; Lech et al.
"Vectors derived from Lambda and Related Bacteriophages" Section
III and Id. pages 1-28 to page 1-52.
[0631] To express a protein, including but not limited to a fusion
protein, in a eubacterial cell, it is necessary to operably link
the ORF encoding the protein to a functional eubacterial or viral
promoter. Stich promoters may be either constitutive or, more
preferably, regulatable (i.e., inducible or derepressible).
Examples of constitutive promoters include the int promoter of
bacteriophage lambda, the bla promoter of the beta-lactamase gene
sequence of pBR322, and the cat promoter of the chloramphenicol
acetyl transferase gene sequence of pPR325, and the like. Examples
of inducible eubacterial promoters include the major right and left
promoters of bacteriophage lambda (P.sub.L and P.sub.R), the trp,
recA, lacZ, lac, and gal promoters of E. coli, the alpha-amylase
(Ulmanen et al., J. Bacteriol. 162:176-182, 1985) and the
sigma-28-specific promoters of B. subtilis (Gilman et al., Gene
Sequence 32:11-20, 1984), the promoters of the bacteriophages of
Bacillus (Gryczan, in: The Molecular Biology of the Bacilli,
Academic Press, Inc., NY, 1982), and Streptomyces promoters (Ward
et al., Mol. Gen. Genet. 203:468-478, 1986). Eubacterial promoters
are reviewed by Glick (Ind. Microbiot. 1:277-282, 1987), Cenatiempo
(Biochimie 68:505-516, 1986), and Gottesman (Ann. Rev. Genet.
18:415-442, 1984).
[0632] Proper expression also requires the presence of a
ribosome-binding site upstream of the gene sequence-encoding
sequence. Such ribosome-binding sites are disclosed, for example,
by Gold et al. (Ann. Rev. Microbiol. 35:365-404, 1981). The
selection of control sequences, expression vectors, transformation
methods, and the like, are dependent on the type of host cell used
to express the gene. As used herein, "cell", "cell line", and "cell
culture" may be used interchangeably and all such designations
include progeny. Thus, the words "transformants" or "transformed
cells" include the primary subject cell and cultures derived
therefrom, without regard to the number of transfers. It is also
understood that all progeny may not be precisely identical in DNA
content, due to deliberate or inadvertent mutations. However, as
defined, mutant progeny have the same functionality as that of the
originally transformed cell.
[0633] Mammalian expression systems utilize host cells such as HeLa
cells, cells of fibroblast origin such as VERO or CHO-K1, or cells
of lymphoid origin and their derivatives. Preferred mammalian host
cells include SP2/0 and J558L, as well as neuroblastoma cell lines
such as IMR 332, which may provide better capacities for correct
post-translational processing. Non-limiting examples of mammalian
extrachromosomal expression vectors include pCR3.1 and pcDNA3.1,
and derivatives thereof including but not limited to those that are
described by and are commercially available from Invitrogen
(Carlsbad, Calif.).
[0634] Several expression vectors are available for the expression
of polypeptides in mammalian host cells. A wide variety of
transcriptional and translational regulatory sequences may be
employed, depending upon the nature of the host. The
transcriptional and translational regulatory signals may be derived
from viral sources, such as adenovirus, bovine papilloma virus,
cytomegalovirus (CMV), simian virus, or the like, where the
regulatory signals are associated with a particular gene sequence
which has a high level of expression. Alternatively, promoters from
mammalian expression products, such as actin, collagen, myosin, and
the like, may be employed. Transcriptional initiation regulatory
signals may be selected which allow for repression or activation,
so that expression of the gene sequences can be modulated. Of
interest are regulatory signals that are temperature-sensitive
since, by varying the temperature, expression can be repressed or
initiated, or are subject to chemical (such as metabolite)
regulation.
[0635] Preferred eukaryotic plasmids include, for example, BPV,
vaccinia, SV40, 2-micron circle, and the like, or their
derivatives. Such plasmids are well known in the art (Botstein et
al., Miami Wntr. Symp. 19:265-274, 1982; Broach, in: The Molecular
Biology of the Yeast Saccharomyces: Life Cycle and Inheritance,
Cold Spring Harbor Laboratory, Cold Spring Harbor, N.Y., p.
445-470, 1981; Broach, Cell 28:203-204, 1982; Bollon et al., J.
Clin. Hematol. Oncol. 10:39-48, 1980; Maniatis, In: Cell Biology: A
Comprehensive Treatise, Vol. 3, Gene Sequence Expression, Academic
Press, N.Y., pp. 563-608, 1980).
[0636] Expression of polypeptides in eukaryotic hosts generally
involves the use of eukaryotic regulatory regions. Such regions
will, in general, include a promoter region sufficient to direct
the initiation of RNA synthesis. Preferred eukaryotic promoters
include, for example, the promoter of the mouse metallothionein I
gene sequence (Hamer et al., J. Mol. Appl. Gen. 1:273-288, 1982);
the TK promoter of Herpes virus (McKnight, Cell 31:355-365, 1982);
the SV40 early promoter (Benoist et al., Nature (London)
290:304-31, 1981); and the yeast gal4 gene sequence promoter
(Johnston et al., Proc. Natl. Acad. Sci. (USA) 79:6971-6975, 1982;
Silver et al., Proc. Natl. Acad. Sci. (USA) 81:5951-5955,
1984).
[0637] Expression sequences and elements are also required for
efficient expression. Non-limiting examples include Kozak and IRES
elements in eukaryotes, and Shine-Delgarno sequences in
prokaryotes, which direct the initiation of translation (Kozak,
Initiation of translation in prokaryotes and eukaryotes. Gene,
1999. 234: 187-208; Martinez-Salas et al., Functional interactions
in internal translation initiation directed by viral and cellular
IRES elements, Jour. of Gen. Virol. 82:973-984, 2001); enhancer
sequences; optioanl sites for repressor and inducers to bind; and
recognition sites for enaymes that cleave DNA or RNA in a
site-specific manner. Translation of mRNA is generally initiated at
the codon which encodes the first methionine; if so, it is
preferable to ensure that the linkage between a eukaryotic promoter
and a preselected ORF does not contain any intervening codons that
encode a methionine (i.e., AUG). The presence of such codons
results either in the formation of a fusion protein with an
uncharacterized N-terminal extension (if the AUG codon is in the
same reading frame as the ORF) or a frame-shift mutation (if the
AUG codon is not in the same reading frame as the ORF).
[0638] XI.B. Expression of Membrane Proteins
[0639] Presently, the most commonly used expression systems for the
expression of integral membrane proteins are eukaryotic and
eubacterial whole cell expression systems. Although minicells have
been used to express several eubacterial membrane proteins, the
production of non-eubacterial membrane proteins has not been
reported. One aspect of the invention is the discovery that the
minicell expression system can be made to express and preferably
display integral membrane proteins from non-eubacterial
organisms.
[0640] Some commonly used expression systems include in vitro
systems, such as the Rabbit Reticulocyte Lysate System and E. coli
S30 Extract System (both available from Promega) (Zubay, Methods
Enz. 65:856, 1980) and in vivo systems, such as eukaryotic cell
culture expression, and bacterial expression systems. Although this
is not an exhaustive list, these systems are representative.
[0641] The Rabbit Reticulocyte Lysate system utilizes a cell lysate
that contains all the enzymes required for transcription and
translation to drive protein expression, and is a good in vitro
system for producing small amounts of labeled and unlabeled
protein. However, this system is not well-suited for the production
of large quantities of proteins and is limited to soluble proteins
as there are no membranes in which to incorporate membrane
proteins.
[0642] In eukaryotic cell culture systems, expression vectors
suited for expression in host eukaryotic cells are transfected into
cultured cells and protein is translated from mRNA produced from
the vector DNA template Kaufman, Overview of vector design for
mammalian gene expression. Mol Biotechnol, 2001. 16: 151-160; Lee,
et al., Heterologous gene expression in avian cells: Potential as a
producer of recombinant proteins. J Biomed Sci, 1999. 6: 8-17;
Voorma et al., Initiation of protein synthesis in eukaryotes. Mol
Biol Rep, 1994.19: 139-45). Cells can then either be harvested to
prepare at least partially purified proteins or proteins produced
from the expression element can be studied in the host cell
environment.
[0643] Regarding membrane proteins, such systems have limitations.
Primary cell lines are difficult to maintain and are short lived.
Immortalized cell lines divide indefinitely, but have been altered
in many ways and can be unpredictable. The transfection efficiency
is very low in most eukaryotic cells and some cell types are
refractory to transformation. Moreover, other proteins are
expressed in these cells along with the protein of interest. This
can cause difficulties when performing certain experiments and when
attempting to immunoprecipitate the protein. Good experimental data
are difficult to obtain from studies such as binding assays
(because of high background due to endogenous proteins), and
crystal determination of protein structure (because it is difficult
to obtain enough purified protein to efficiently form
crystals).
[0644] Bacterial expression systems are generally similar to that
of the eukaryotic expression systems in that they both use the host
cell enzymes to drive protein expression from recombinant
expression vectors (Cornelis, P., Expressing genes in different
Escherichia coli compartments. Curr Opin Biotechnol, 2000. 11: p.
450-454; Laage and Langosch, Strategies for prokaryotic expression
of eukaryotic membrane proteins. Traffic, 2001. 2: 99-104; Pines,
0. and M. Inouye, Expression and secretion in E. coli. Mol
Biotechnol, 1999. 12: 25-34).
[0645] In bacterial expression systems, bacterial cells are
transformed with expression elements, and transcription and
translation is driven from a bacterial promoter. Bacteria divide
very rapidly and are easy to culture; it is relatively easy to
produce a large number of bacteria in a short time. Moreover,
incorporation of expression elements vector into bacterial cells is
efficient. Transformed cells can be isolated that arise from a
single bacterium. Cultures of transformed cells are thus
genetically identical and all cells in the culture will contain the
expression element. However, there are proteins that are not
suitable for expression in bacteria because of differences between
eukaryotic cells and bacterial cells in transcription, translation,
and post-translational modification.
[0646] The E. coli whole cell expression system has been used to
express functional integral membrane proteins. For a review, see
Strosberg, Functional expression of receptors in microorganisms.
TiPS, 1992. 13: 95-98. Examples of mammalian integral membrane
proteins that have been expressed in Escherichia coli include rat
alpha-2B-adrenoceptors (Xia et al., Functional expression of rat
.beta.2B-adrenoceptor in E. coli. Euro J. Pharma, 1993. 246:
129-133) and the human beta2-adrenergic receptor (Marullo et al.,
Human .beta.2-adrenergic receptors expressed in Escherichia coli
membranes retain their pharmacological properties. Proc. Natl.
Acad. Sci. USA, 1988. 85: 7551-7555). In some of these studies, the
integral membrane proteins were not only expressed in E. coli
expression systems, but also retained their pharmacological
properties. This allows for binding studies to be performed with
minimal background signal ("noise") from host cell proteins. It has
also been shown that signal sequences (the short hydrophobic amino
acid sequence at the N-terminus of integral membrane proteins that
signals the transport of the protein to the membrane) from
mammalian cells may be functional in the E. coli system.
[0647] As is discussed herein, the expression of membrane proteins
such as GPCRs, ion channels, and immuno-receptors in minicells, and
their incorporation into the membranes thereof, allows for the
study and use of such non-eubacterial membrane proteins. The
minicell system of the invention is particularly well-suited for
the study and expression of EDG proteins because of the lipid
nature of the ligands for these receptors. The identification of
ligand binding kinetics and biochemistry of these receptors because
of the physiochemical properties of the lipid ligands (LPA and
SIP), which results in high non-specific binding (Lee et al.,
Sphingosine-1-phosphate is a ligand for the G protein-coupled
receptor EDG-1. Science, 1998. 279: 1552-1555; Van Brocklyn et al.,
Sphingosine-1-phosphate is a ligand for the G protein-coupled
receptor EDG-6. Blood, 2000. 95: 2624-2629; Liu et al., Edg-1, the
G protein-coupled receptor for sphingosine-1-phosphate, is
essential for vascular maturation. J. Clin. Investigation, 2000.
106: 951-961).
[0648] It is believed, for example, that in the case of the ion
channels, the minicell expression system is less cumbersome then
procedures that are presently used to study properties of ion
channels, such as, e.g., reconstitution studies (Montal, Molecular
anatomy and molecular design of channel proteins. FASEB J., 1990.
4: p. 2623-2635). Ionic conditions both inside and outside of
minicells can be manipulated in various ways, and the properties of
an ion channel that is expressed in a minicell, and factors that
activate or modulate the activities of the channel, can be studied.
Binding and kinetic studies are performed on ligand mediated ion
channels. This type of study is enhanced when the ion channel is
able to interact specifically with its ligand and has a low
background of non-specific binding from the endogenous proteins.
This can be accomplished by making the minicells into protoplasts
or poroplasts in which the ligand-activated ion channels in the
inner membrane are exposed to the external environment and have
better access to their specific ligand.
[0649] A "recombinant expression system" (or simply "expression
system") is one that directs the production of exogenous gene
products in a host cell or minicell of choice. By "expressed" it is
meant that a gene product of interest (which can be a protein or
nucleic acid) is produced in the expression system of choice.
[0650] Host cells (and/or minicells) harboring an expression
construct are components of expression systems. An "expression
vector" is an artificial nucleic acid molecule into which an
exogenous ORF encoding a protein, or a template of a bioactive
nucleic acid can be inserted in such a manner so as to be operably
linked to appropriate expression sequences that direct the
expression of the exogenous gene. By the term "operably linked" it
is meant that the part of a gene that is transcribed is correctly
aligned and positioned with respect to expression sequences that
promote, are needed for and/or regulate this transcription. The
term "gene product" refers to either a nucleic acid (the product of
transcription, reverse transcription, or replication) or a
polypeptide (the product of translation) that is produced using the
non-vector nucleic acid sequences as a template.
[0651] In some applications, it is preferable to use an expression
construct that is an episomal element. If the episomal expression
construct expresses (or, preferably in some applications,
over-expresses) a an ORF that has been incorporated into the
episomal expression construct, the minicells will direct the
production of the polypeptide encoded by the ORF. At the same time,
any mRNA molecules transcribed from a chromosomal gene prior to
minicell formation that have been transferred to the minicell are
degraded by endogenous RNases without being replaced by new
transcription from the (absent) bacterial chromosome.
[0652] Chromosomally-encoded mRNAs will not be produced in
minicells and will be "diluted" as increasing amounts of mRNAs
transcribed from the episomal element are generated. A similar
dilution effect is expected to increase the relative amount of
episomally-generated proteins relative to any chromosomally-encoded
proteins present in the minicells. It is thus possible to generate
minicells that are enriched for proteins encoded by and expressed
from episomal expression constructs.
[0653] Although by no means exhaustive, a list of episomal
expression vectors that have been expressed in eubacterial
minicells is presented in Table 4.
[0654] It is also possible to transform minicells with exogenous
DNA after they have been prepared or separated from their parent
cells. For example, phage RNA is produced in minicells after
infection by lambda phage (Witkiewicz and Taylor, Ribonucleic acid
synthesis after adsorption of the bacteriophage lambda on
Escherichia coli minicells, Acta Microbiol Pol A 7:21-4, 1975),
even though replication of lambda phage may not occur in minicells
(.Witkiewicz and Taylor, The fate of phage lambda DNA in
lambda-infected minicells, Biochim Biophys Acta 564:31-6,
1979).
[0655] Because it is the most characterized minicell-producing
species, many of these episomal elements have been examined in
minicells derived from E. coli. It is understood by practitioners
of the art, however, that many episomal elements that are expressed
in E. coli also function in other eubacterial species, and that
episomal expression elements for minicell systems in other species
are available for use in the invention disclosed herein.
[0656] In one aspect of the invention, eukaryotic and
archeabacterial minicells are used for expression of membrane
proteins, particularly in instances where such desirable proteins
have enhanced or altered activity after they undergo
post-translational modification processes such as phosphorlyation,
proteolysis, mystrilation, GPI anchoring and glycosylation.
Expression elements comprising expression sequence operably linked
to ORFs encoding the membrane proteins of interest are transformed
into eukaryotic cells according to methods and using expression
vectors known in the art. By way of non-limiting example, primary
cultures of rat cardiomyocytes have been used to produce exogenous
proteins after transfection of expression elements therefor by
electroporation (Nakajima et al., Expression and characterization
of Edg-1 receptors in rat cardiomyocytes: Calcium deregulation in
response to sphingosine-1-phosphate, Eur. J. Biochem.
267:-5679-5686, 2000).
[0657] Yeast cells that produce minicells are transformed with
expression elements comprising an ORF encoding a membrane protein
operably linked to yeast expression sequences. Cells that harbor a
transferred expression element may be selected using a gene that is
part of the expression element that confers resistant to an
antibiotic, e.g., neomycin.
[0658] Alternatively, in one aspect of the invention, bacterial
minicells are prepared that contain expression elements that are
prepared from shuttle vectors. A "shuttle vector" has sequences
required for its replication and maintenance in cells from two
different species of organisms, as well as expression elements, at
least one of which is functional in bacterial cells, and at least
one of which is functional in yeast cells. For example, E.
coli-yeast shuttle vectors are known in the art and include, by way
of non-limiting example, those derived from Yip, Yrp, Ycp and Yep.
Preferred E. coli-yeast shuttle vectors are episomal elements that
can segregate into yeast minicells (i.e., Yrp, Ycp and Yep.
Particularly preferred are expression vectors of the Yep (yeast
episomal plasmid) class, and other derivatives of the naturally
occurring yeast plasmid known as the 2 .mu.m circle. The latter
vectors have relatively high transformation frequencies and are
stably maintained through mitosis and meiosis in high copy
number.
4TABLE 4 Episomal Elements That Segregate Into Escherichia coli
Minicells EPISOMAL ELEMENT REFERENCES Plasmids R6K, R1DRD19 Nesvera
et al., Folia Microbiol. (Praha) 23: 278-285 (1978) PSC101 Fox et
al., Blood 69: 1394-1400 (1987) PBR322 Fox et al., Blood 69:
1394-1400 (1987) F element Cohen et al., Proc. Natl. Acad. Sci. 61:
61-68 (1968); Khachatourians G. G., Biochim. Biophys. Acta. 561:
294-300 (1979) NR1 Hochmannova et al., Folia Microbiol. (Praha) 26:
270-276 R6.delta.1 Hochmannova et al., Folia Microbiol. (Praha) 26:
270-276 PTTQ18 Rigg et al., Arch. Oral. Biol. 45: 41-52 (2000)
PGPR2.1 Rigg et al., Arch. Oral. Biol. 45: 41-52 (2000); expresses
cell surface antigen of P. gingivalis "mini-plasmid" derivative of
Firshein et al., J. Bacteriol. 150: 1234-1243 (1982) RK2 ColE1
Rashtchian et al., J. Bacteriol. 165: 82-87 (1986); Witkiewicz et
al., Acta. Microbiol. Pol. A 7: 21-24 (1975) PSC101 Rashtchian et
al., J. Bacteriol. 165: 82-87 (1986); Curtiss, Roy, III, U.S. Pat.
No. 4,190,495; Issued Feb. 26, 1980 pACYC184 Chang et al., J.
Bacteriol. 134: 1141-1156 (1978); Rose, Nucleic Acids Res 16: 355
(1988) Co1Ib, Co1Ib7 DRD& Skorupska et al., Acta. Microbiol.
Pol. A 8: 17-26 (1976) pUC19 Heighway et al., Nucleic Acids Res.
17: 6893-6901 (1989) R-plasmid Hochmannova et al., Folia Microbiol.
(Praha) 25: 11-15 (1980) PCR1 Hollenberg et al., Gene 1: 33-47
(1976); yeast shuttle vector Bacteriophage Lambda Witkiewicz et
al., Acta. Microbiol. Pol. A 7: 21-24 (1975) M13 Staudenbauer et
al., Mol. Gen. Genet. 138: 203-212 (1975) T7 Libby, Mech Ageing
Dev. 27: 197-206 (1984) P1 Curtiss, Roy, III, U.S. Pat. No.
4,190,495; Issued Feb. 26, 1980; J Bacteriol 1995; 177: 2381-6,
Partition of P1 plasmids in Escherichia coli mukB chromosomal
partition mutants, Funnell and Gagnier.
[0659] For expression of membrane proteins, and/or other proteins
of interest in the recipient cell, ORFs encoding such proteins are
operably linked to eukaryotic expression sequences that are
appropriate for the recipient cell. For example, in the case of E.
coli-yeast shuttle vectors, the ORFs are operably linked to
expression sequences that function in yeast cells and/or minicells.
In order to assess the effectiveness of a gene delivery vehicle, or
a gene therapy expression element, an ORF encoding a detectable
polypeptide (e.g., GFP, beta-galactosidase) is used. Because the
detectable polypeptide is operably linked to eukaryotic expression
elements, it is not expressed unless it has been transferred to its
recipient (eukaryotic) cell. The signal from the detectable
polypeptide thus correlates with the efficiency of gene transfer by
a gene delivery agent, or the degree of expression of a eukaryotic
expression element.
[0660] Gyuris and Duda (High-efficiency transformation of
Saccharoymces cells by bacterial minicell protoplast fusion, Mol
Cel Biol 6:329507, 1986) allegedly demonstrated the transfer of
plasmid molecular by fusing minicell protoplasts with yeast
protoplasts. Gyuris and Duda state that 10% of Saccharomyces
cerevisiae cells were found to contain transforming DNA sequences.
However, the plasmids did not contain eukaryotic expression
elements, were not shuttle vectors, and genetic expression of the
plasmids in yeast cells was not examined.
XII. Uses of Minicells in Research
[0661] XII.A. In General
[0662] The minicells of the invention can be used in research
applications such as, by way of non-limiting example, proteomics,
physiology, chemistry, molecular biology, physics, genetics,
immunology, microbiology, proteomics, virology, pathology, botany,
and neurobiology. Research applications include but are not limited
to protein-ligand binding studies, competitive inhibition studies,
structural studies, protein interaction studies, transfection,
signaling studies, viral interaction studies, ELISA, antibody
studies, gel electrophoresis, nucleotide acid) applications,
peptide production, cell culture applications, cell transport
studies, isolation and separation studies, chromatography, labeling
studies, synthesis of chemicals, chemical cross linking, flow
cytometry, nanotechnology, micro switches, micro-machines,
agricultural studies, cell death studies, cell-cell interactions,
proliferation studies, and protein-drug interactions. Minicells are
applicable to research applications involving, by way of
non-limiting example, the elucidation, manipulation, production,
replication, structure, modeling, observations, and
characterization of proteins.
[0663] The types of proteins that can be involved in research
applications of minicells can be either soluble proteins or
membrane bound proteins, and include but are not limited to
receptors (e.g., GPCRs, sphingolipid receptors, neurotransmitter
receptors, sensory receptors, growth factor receptors, hormone
receptors, chemokine receptors, cytokine receptors, immunological
receptors, and compliment receptors, FC receptors), channels (e.g.,
potassium channels, sodium channels, calcium channels.), pores
(e.g., nuclear pore proteins, water channels), ion and other pumps
(e.g., calcium pumps, proton pumps), exchangers (e.g.,
sodium/potassium exchangers, sodium/hydrogen exchangers,
potassium/hydrogen exchangers), electron transport proteins (e.g.,
cytochrome oxidase), enzymes and kinases (e.g., protein kinases,
ATPases, GTPases, phosphatases, proteases.), structural/linker
proteins (e.g., Caveolins, clathrin), adapter proteins (e.g., TRAD,
TRAP, FAN), chemotactic/adhesion proteins (e.g., ICAM11, selectins,
CD34, VCAM-1, LFA-1,VLA-1), and chimeric/fusion proteins (e.g.,
proteins in which a normally soluble protein is attached to a
transmembrane region of another protein).
[0664] Research products are designed for any specific type of
application. These products may be packaged and distributed as, by
way of non-limiting example, kits, chemicals, solutions, buffers,
powders, solids, filters, columns, gels, matrixes, emulsions,
pellets, capsules, and aerosols. Kits and reagents for certain
research applications may be required by regulatory agency to be
labeled "research use only" in order to indicate that the reagents
are not intended for use in humans.
[0665] XII.B. Transfection
[0666] Transfection is the process of introducing genetic material
into eukaryotic and archaebacterial cells using biological,
biochemical or physical methods. This process allows researchers to
express and study target proteins in cultured cells (research use)
as well as to deliver genetic material to cells in vivo or ex vivo
systems (gene therapy). There are a variety of techniques which
allow for the introduction and expression of proteins into target
cells. These include mechanical transfection (Biolistic particles
and Electroporation), calcium phosphate, DEAE-dextran/polybrene,
viral based techniques and lipid based techniques.
[0667] The genetic material and/or nucleic acid to be delivered can
be, by way of non-limiting example, nucleic acids that repair
damaged or missing genes, nucleic acids for research applications,
nucleic acids that kill a dysfunctional cell such as a cancer cell,
antisense oligonucleotides to reduce or inhibit expression of a
gene product, genetic material that increases expression of another
gene, nucleotides and nucleotide analogs, peptide nucleic acids
(PNAs), tRNAs, rRNAs, catalytic RNAs, RNA:DNA hybrid molecules, and
combinations thereof.
[0668] The genetic material may comprise a gene expressing a
protein. exemplary proteins include, but are not limited to,
receptors (e.g., GPCRs, sphingolipid receptors, neurotransmitter
receptors, sensory receptors, growth factor receptors, hormone
receptors, chemokine receptors, cytokine receptors, immunological
receptors, and compliment receptors, FC receptors), channels (e.g.,
potassium channels, sodium channels, calcium channels.), pores
(e.g., nuclear pore proteins, water channels), ion and other pumps
(e.g., calcium pumps, proton pumps), exchangers (e.g.,
sodium/potassium exchangers, sodium/hydrogen exchangers,
potassium/hydrogen exchangers), electron transport proteins (e.g.,
cytochrome oxidase), enzymes and kinases (e.g., protein kinases,
ATPases, GTPases, phosphatases, proteases), structural/linker
proteins (e.g., Caveolins, clathrin), adapter proteins (e.g., TRAD,
TRAP, FAN), chemotactic/adhesion proteins (e.g., ICAM11, selectins,
CD34, VCAM-1, LFA-1,VLA-1), and chimeric/fusion proteins (e.g.,
proteins in which a normally soluble protein is attached to a
transmembrane region of another protein).
[0669] A minicell that is used to deliver therapeutic agents may
comprise and display a binding moiety. By way of non-limiting
example, binding moieties used for particular purposes may be a
binding moiety directed to a compound or moiety displayed by a
specific cell type or cells found predominantly in one type of
tissue, which may be used, among other things, to target minicells
and their contents to specific cell types or tissues. A preferred
binding moiety is an antibody or antibody derivative. Other binding
moieties include, but are not limited to, receptors, enzymes,
ligands, binding peptides, fusion proteins, small molecules
conjugated to transmembrane proteins, ligands conjugated to
transmembrane proteins, viral fusion proteins, and fusion/chimeric
proteins.
[0670] A minicell containing genetic material may be to a target
cell by methods including, but not limited to, receptor mediated
endocytosis, cell fusion, or phagocytosis (Aderem et al., Mechanism
of Phagocytosis in Macrophages, Annu. Rev. Immunol. 17:593-623,
1999). The minicell gene delivery system is used to deliver genetic
material in culture for research applications as well as to cells
in vivo as part of gene therapy or other therapeutic
applications.
[0671] By way of non-limiting example, a minicell may express a
protein such as invasin to induce receptor mediated endocytosis
(Pepe et al., "Yersinia enterocolitica invasin: A primary role in
the initiation of infection," Proc. Natl. Acad. Sci. U.S.A.
90:6473-6477, 1993; Alrutz et al., "Involvement of focal adhesion
kinase in invasin-mediated uptake," Proc. Natl. Acad. Sci. U.S.A.
95:13658-13663, 1998). Invasin interacts with the Beta2 Integrin
protein and causes it to dimerize. Upon dimerization the Beta2
Integrin signals for an endocytotic event. Thus a minicell
expressing the invasin protein will be taken up by cells expressing
Beta2 Integrin via endocytosis.
[0672] Another non-limiting example of the minicell gene delivery
and transfection system using invasin involves the expression of
invasin following a targeting event. In this example, a minicell
expresses a targeting protein that is capable of bringing the
minicell in contact with a specific target cell Upon contact with
the target cell, the minicell will be induced to transcribe and
translate invasin. The induction is accomplished via signaling
events or with a transcription factor dimerization event. The
minicells can be engineered to contain targeting proteins that
induce protein expression only upon contact with a specific target
cell. By way of non-limiting example, the invasin is expressed only
at the target cell where it induces endocytosis, thus preventing
the minicell from entering any cell but the target cell.
[0673] Proteins can be induced and expressed post contact with
target cells include but are not limited to antibodies and antibody
derivatives, receptors, enzymes, ligands, binding peptides, fusion
proteins, small molecules conjugated to transmembrane proteins,
ligands conjugated to transmembrane proteins, viral fusion
proteins, antibiotics, apoptotic proteins, hormones, toxins,
poisons, and fusion/chimeric proteins.
[0674] Another non-limiting example of gene delivery or
transfection using the minicell involves the use of the type III
secretion apparatus of bacteria. The type III secretion apparatus
is expressed in the minicell and used to transfer genetic material
to a target cell.
[0675] Another non-limiting example of gene delivery and
transfection using minicells involves minicells that have been
engineered to contain anionic lipids or cationic lipids (Axel et
al., "Toxicity, Uptake Kinetics and Efficacy of New Transfection
Reagents: Increase of Oligonucleotide Uptake," Jour. of Vasc. Res.
040:1-14, 2000). Many types of lipids have been shown to induce or
enhance transfection and gene delivery in a variety of cell types.
Minicells containing such lipids could be used to transfer genetic
material to specific cell types. Minicells can also be engineered
to express targeting proteins that would allow the minicell to
associate tightly with a target cell, which will facilitate the
lipid interactions and gene transfer.
[0676] Another non-limiting example of gene delivery or
transfection using minicells involves the use of ligands to induce
receptor mediated endocytosis. By way of non-limiting example, the
ligand is expressed on the surface of the minicell, or is attached
to the surface of the minicell. A minicell containing genetic
material is then able to associate with a target cell expressing
the target receptor for the ligand. The receptor/ligand interaction
will result in the endocytosis of the minicell into the target cell
where the minicell would release and deliver the genetic
material.
[0677] Another non-limiting example of gene delivery or
transfection using minicells involves the use of fusion proteins,
such as but not limited to viral capsid proteins. In this example
the fusion protein would be expressed or attached to the outside of
the minicell. The fusion protein would then induce fusion of a
target cell with the minicell upon contact. The contact could be
initiated via random non-targeting events or via the use of
specific targeting proteins. In both cases the end result would be
the fusion of the minicell with a target cell and the delivery of
the genetic material.
[0678] XII.C. Non-Limiting Examples of Research Applications of
Minicells
[0679] XII.C. 1. Phage Interactions with Bacterial Membranes
[0680] One non-limiting example of a research application for
minicells would be the study of phage interactions with a bacterial
membrane. The minicells could be used to study how phage associate
and enter into a host bacterium. Another non-limiting example is
the research application of minicells is to study isolated cell
signaling pathways. The proteins of a signaling pathway could be
expressed in the minicell and the signal cascade could be
monitored. Another non-limiting example of research applications is
the use of minicells to determine how recombination events occur.
In this example the minicell is used to provide an environment to
study the recombination event between two episomal plasmid DNA
units.
[0681] XII.C.2. Matrices
[0682] Another non-limiting example of a research application of
minicells is to form chromatography matrices for
immunoprecipitation, isolation and separation techniques. The
minicell can express and display target proteins with binding
activity, including but not limited to antibodies and antibody
derivatives. The minicell is then used to generate a matrix and
loaded in a column or tube. The solution to be separated is mixed
or passed through the column allowing the minicell to bind its
target. The minicells are then separated away with the attached
substance.
[0683] XII.C.3. Mutagenesis
[0684] Another non-limiting example of a research application for
minicells involves site directed mutagenesis studies of target
proteins. In this application minicells are generated to express
target proteins with various mutations and deletions to study if
function is compromised, enhanced or has an altered specificity for
ligand binding.
[0685] XII.C.4. Metabolic Pathways
[0686] Another non-limiting example of research applications for
minicells involves the study of metabolic rates of proteins and
metabolites. The minicell can be generated to express metabolic
pathways and the kinetics and. function of that pathway can be
studied.
[0687] XII.C.5. Cell Free Production of Proteins
[0688] Another non-limiting example of a research application for
minicells involves uses in cell free production of functional
proteins (Jermutus et al., Recent advances in producing and
selecting functional proteins by using cell-free translation,
Current Opinion in Biotechnology 9:534-548, 1999). Minicells can be
prepared as a reagent used to prepare compositions for in vitro
translation. As is described in detail elsewhere herein, the
composition of minicells can be manipulated so as to be enriched
for particular proteins or nulceic acids, including those involved
in protein translation and folding and/or modification of the
proteins so produced into functional forms, i.e., forms having the
activity of the corresponding protein as it is isolated from
natural sources. Non-limiting examples of such proteins and nulceic
acids are ribosomal RNAs, ribosomal proteins, tRNAs, and the
like.
[0689] XII. C.6. Assays
[0690] Minicells could also be used in manual, semi-automated,
automated and/or robotic assays for the in vitro determinations of
the compounds of interest including, by way of non-limiting
example, ligands, proteins, small molecules, bioactive lipids,
drugs, heavy metals, and the like in environmental samples (e.g.,
air, water, soil), blood, urine or tissue of humans or samples from
non-human organisms (e.g., plants, animals, protists) for the
purpose of quantifying one or more compounds in a sample. A
non-limiting example of this type of research applications is the
expression on the surfaces of the minicells of a receptor such as
the receptor that binds a toxin produced by Baccillus anthracis.
The protein, protective antigen (PA), is a 82.7 kDa protein that
binds one of the secreted anthrax toxins, lethal factor (LF) (see
Price, B. et al., Infection and Immunity 69: 4509-4515. 2001).
Minicells expressing the PA protein could be used to detect LF in
an environmental sample or in human blood, urine or tissue for the
purposes of determining the presence of anthax. As a non-limiting
example, a competitive binding assay or an antibody-based assay
could be used to indicate binding of LF in the environmental or
tissue sample. Another non-limiting example is the use of
PA-expressing minicells in a lateral flow diagnostic where
interaction between the minicells and the LF-containing sample is
indicated by the presence of a colored reaction product on a test
strip.
XIII. Minicell-Based Delivery of Biologically Active Agents
[0691] XIII.A. General Considerations
[0692] The minicells of the invention are capable of encapsulating
and/or loading into a membrane a variety of substances, including
but not limited to biologically active agents, including but not
limited to diagnostic and therapeutic agents. Biologically active
agents include, but are not limited to, nucleic acids, e.g., DNA,
RNA, gene therapy constructs, ribozymes, antisense and other
synthetic oligonucleotides including those with chemical
modifications; peptide nucleic acids (PNAs); proteins; synthetic
oligopeptides; peptomimetics; small molecules; radioisotopes;
antibiotics; antibodies and antibody derivatives; and combinations
and/or prodrugs of any of the preceding.
[0693] The surface of a minicell may be chemically altered in order
to have certain properties that are desirable for their use as drug
delivery agents. By way of non-limiting example, minicells may be
chemically conjugated to polyethylene glycol (PEG), which provides
for "stealth" minicells that are not taken as well and/or as
quickly by the reticuloendothelial system (RES). Other compounds
that may be attached to minicells include without limitation
polysaccharides, polynucleotides, lipopolysaccharides,
lipoproteins, glycosylated proteins, synthetic chemical compounds,
and/or combinations of any of the preceding.
[0694] A minicell that is used to deliver therapeutic agents may
comprise and display a binding moiety. By way of non-limiting
example, binding moieties used for particular purposes may be a
binding moiety directed to a compound or moiety displayed by a
specific cell type or cells found predominantly in one type of
tissue, which may be used, among other things, to target minicells
and their contents to specific cell types or tissues. A preferred
binding moiety is an antibody or antibody derivative, which are
described in detail elsewhere herein. Other binding moieties
include, but are not limited to, receptors, enzymes, ligands,
binding peptides, fusion proteins, small molecules conjugated to
transmembrane proteins, ligands conjugated to transmembrane
proteins, viral fusion proteins, and fusion/chimeric proteins.
[0695] XIII.B. Cellular Uptake
[0696] In addition to binding moieties, proteins and other
compounds that induce or enhance the uptake or fusion of the
minicell with the target gene can be displayed on the surface of a
minicell for applications involving the delivery of therapeutic
agents, gene therapy, and/or transfection or other research
applications. See, generally, Adhesion Protein Protocols, Vol. 96,
Dejana, E. and Corada, M., eds., Humana Press, 1999.
[0697] XIII.B. 1. Cellular Uptake Sequences from Eukaryotic
Cells
[0698] Eukaryotic adhesion receptors, which mediate intercellular
adhesion , can be used as agents or targets for cellular uptake.
There are at least three distinct classes of adhesive molecules
that leukocytes employ during their adhesive interactions (a)
integrins, including but not limited to LEC-CAMS/Selectins (ELAM-1,
LAM-1/Leu8/TQ1, and GMPI40/PADGEM); (b) those belonging to the
immunoglobulin superfamily including but not limited to CD2(LFA-2),
CD3/TCR, CD4, CD8, CD28, CD44,CD54 (ICAM-1), ICAM-2, CD58 (LFA-3),
VCAM-1,B7; and (c) Class I and II Major Histocompatability Antigens
(MHC).
[0699] The adhesion receptors that belong to the integrin family
and control intercellular interactions are of particular interest.
At least ten different structurally related cell surface
heterodimeric (alpha and beta complexes) molecules have been
defined as integrins and further classified into subfamilies
(Springer T. A., 1990, Nature 346:425-434; Hynes, R. O., 1987, Cell
48:549-554; Moller, G. Editor, 1990, Immunol. Rev. 114.:1-217).
Each subfamily has a unique beta subunit, designated integrin betal
(CD29), integrin beta2 (CD18), and integrin beta3 (CD61), each of
which can associate with multiple alpha subunits, each with at
least one di-valent cation binding site. The integrin family
includes receptors for extracellular matrix components such as
fibronectin, laminin, vitronectin, and collagen which recognize
Arg-Gly-Asp in their ligands and utilize the betal or beta3
subunits (Springer T. A., 1990, Nature 346:425-434; Hynes, R. O.,
1987, Cell 48:549-554; Hemler, M. E., 1988, Immunol. Today
9:109-113; Patarroyo, M., and Makgoba, M. W., 1989, Scand. J.
Immunol. 30:129-164; Moller, G. Editor, 1990, Immunol. Rev.
11.4:1-217). There are at least six distinct alpha subunits alpha1
(CD49a), alpha2 (CD49b), alpha3 (CD49c), alpha4 (CD49d), alpha5
(CD49e), and alpha (CD49f) capable of associating with betal
(CD29). The betal integrins are expressed on many nonhematopoietic
and leukocyte cell types and are thought to play an active role in
tissue organization by binding to extracellular matrix components
found in many tissues and in the basement membranes underlying
muscles, nervous system, epithelium and endothelium. While the
expression of many betal integrins on leukocytes requires
consistent activation, their expression on nonhematopoietic cells
does not (Hemler, M. E., 1988, Immunol. Today 9:109-113; Patarroyo,
M., and Makgoba, M. W., 1989, Scand. J. Immunol. 30:129-164). The
complexity of the integrin family has been increased by the
discovery of novel beta subunits beta3 (CD61), beta4 and beta5 that
can associate with alpha 4, alpha 6, and alpha V subunits (Springer
T. A., 1990, Nature 346:425-434; Hemler, M. E., 1988, Immunol.
Today 9:109-113). This combinatorial use of alpha and beta subunits
confers considerable diversity in ligand recognition and also helps
regulate communications between the inside and outside of the
cell.
[0700] By way of non-limiting example, a minicell display an
adhesion receptor, or a fusion protein that has a transmembrane
domain linked to a functional portion of an adhesion receptor. Such
minicells will bind to cells displaying the ligand for the adhesion
receptor.
[0701] XIII.B.2. Cellular Uptake Sequences from Prokaryotes
[0702] Bacterial adhesion proteins are another source of
polypetides that are used to stimulate uptake of minicells. See,
generally, Handbook of Bacterial Adhesion: Principles, Methods, and
Applications, Yuehuei H. An; Richard J. Friedman, eds., Humana
Press, 2000; and Hultgren et al., "Bacterial Adhesions and Their
Assembly," Chapter 150 in: Eschericia coli and Salmonella
typhimurium: Cellular and Molecular Biology, 2.sup.nd Ed.,
Neidhardt, Frederick C., Editor in Chief, American Society for
Microbiology, Washington, D.C., 1996, Volume 2, pages 1903-1999,
and references cited therein.
[0703] By way of non-limiting example, a minicell may express a
protein such as invasin to induce receptor mediated endocytosis
(Pepe et al., Yersinia enterocolitica invasin: A primary role in
the initiation of infection, Proc. Natl. Acad. Sci. U.S.A.
90:6473-6477, 1993; Alrutz et al., Involvement of focal adhesion
kinase in invasin-mediated uptake, Proc. Natl. Acad. Sci. U.S.A.
95:13658-13663, 1998). Invasin interacts with the Beta2 Integrin
protein and causes it to dimerize. Upon dimerization the Beta2
Integrin signals for an endocytotic event. Thus a minicell
expressing the invasin protein will be taken up by cells expressing
Beta2 Integrin via endocytosis.
[0704] As another non-limiting example, the pneumococcal adhesin
protein CpbA interacts with the human polyimmunoglobulin receptor
(hpIgR) as either a part of the outer surface of a bacterial cell
or as a free molecule Zhang et al. (Cell 102:827-837, 2000). The
regions of CpbA:hpIgR interaction were mapped using a series of
large peptide fragments derived from CpbA. CpbA (Swiss-Prot
Accession No. 030874) contains a choline binding domain containing
residues 454-663 and two N-terminal repetitive regions called R1
and R2 that are contained in residues 97-203 and 259-365,
respectively. Polypeptides containing R1 and R2 interact with
hpIgR, whereas polypeptides containing other sequences from CpbA do
not bind to hpIgR. The R1 and/or R2 sequences of the CpbA
polypeptide, and/or essentially identical, substantially identical,
or homologous amino acid sequences, are used to facilitate the
uptake of minicells by cells.
[0705] Another non-limiting example of gene delivery or
transfection using the minicell involves the use of the type III
secretion apparatus of bacteria. The type III secretion apparatus
is expressed in the minicell and used to transfer genetic material
to a target cell.
[0706] Other non-limiting examples of a minicell gene delivery and
transfection targeting moiety are ETA (detoxified exotoxin a)
protein delivery element described in U.S. Pat. No. 6,086,900 to
Draper; Interalin and related proteins from Listeria species
(Galan, Alternative Strategies for Becoming an Insider: Lessons
from the Bacterial World, Cell 103:363-366,2000); Intimin from
pathogenic E. coli strains (Frankel et al., Intimin and the host
cell--is it bound to end in Tir(s)? Trends in Microbiology
9:214-218); and SpeB, streptococcal pyrogenic exotoxin B
(Stockbauer et al., A natural variant of the cysteine protease
virulence factor of group A Streptococcus with an
arginine-glycine-aspartic acid (RGD) motif preferentially binds
human integrins .alpha..sub.v.beta..sub.- 3 and
.alpha..sub.IIb.beta..sub.3 Proc. Natl. Acad. Sci. U.S.A.
96:242-247, 1999).
[0707] XIII.B.3. Cellular Uptake Sequences from Viruses
[0708] Cellular uptake sequences derived from viruses include, but
are not limited to, the VP22 protein delivery element derived from
herpes simplex virus-1 and vectors containing sequences encoding
the VP22 protein delivery element are commercially available from
Invitrogen (Carlsbad, Calif.; see also U.S. Pat. No. 6,017,735 to
Ohare et al.); and the Tat protein delivery element derived from
the amino acid sequence of the Tat protein of human
immunodeficiency virus (HIV). See U.S. Pat. Nos. 5,804,604;
5,747,641; and 5,674,980.
[0709] XIII.B.4. Lipids
[0710] Another non-limiting example of gene delivery and
transfection using minicells involves minicells that have been
engineered to contain anionic lipids or cationic lipids (Axel et
al., Toxicity, Uptake Kinetics and Efficacy of New Transfection
Reagents: Increase of Oligonucleotide Uptake, Jour. of Vasc. Res.
040:1-14, 2000). Many types of lipids have been shown to induce or
enhance transfection and gene delivery in a variety of cell types.
Minicells containing such lipids could be used to transfer genetic
material to specific cell types. Minicells can also be engineered
to express targeting proteins that would allow the minicell to
associate tightly with a target cell, which will facilitate the
lipid interactions and gene transfer.
[0711] Another non-limiting example of gene delivery or
transfection using minicells involves the use of ligands to induce
receptor mediated endocytosis. By way of non-limiting example, the
ligand is expressed on the surface of the minicell, or is attached
to the surface of the minicell. A minicell containing genetic
material is then able to associate with a target cell expressing
the target receptor for the ligand. The receptor/ligand interaction
will result in the endocytosis of the minicell into the target cell
where the minicell would release and deliver the genetic
material.
[0712] Another non-limiting example of gene delivery or
transfection using minicells involves the use of fusion proteins,
such as but not limited to viral capsid proteins. In this example
the fusion protein would be expressed or attached to the outside of
the minicell. The fusion protein would then induce fusion of a
target cell with the minicell upon contact. The contact could be
initiated via random non-targeting events or via the use of
specific targeting proteins. In both cases the end result would be
the fusion of the minicell with a target cell and the delivery of
the genetic material.
[0713] XIII.C. Post-Targeting Expression of Cellular Uptake
Sequences
[0714] Another non-limiting example of the minicell gene delivery
and transfection system using invasin involves the expression of
invasin following a targeting event. In this example, a minicell
expresses a targeting protein that is capable of bringing the
minicell in contact with a specific target cell. Upon contact with
the target cell, the minicell will be induced to transcribe and
translate invasin. The induction is accomplished via signaling
events or with a transcription factor dimerization event. The
minicells can be engineered to contain targeting proteins that
induce protein expression only upon contact with a specific target
cell. By way of non-limiting example, the invasin is expressed only
at the target cell where it induces endocytosis, thus preventing
the minicell from entering any cell but the target cell.
[0715] Proteins can be induced and expressed post contact with
target cells include but are not limited to antibodies and antibody
derivatives, receptors, enzymes, ligands, binding peptides, fusion
proteins, small molecules conjugated to transmembrane proteins,
ligands conjugated to transmembrane proteins, viral fusion
proteins, antibiotics, apoptotic proteins, hormones, toxins,
poisons, and fusion/chimeric proteins.
[0716] XIII.D. Intracellular Targeting and Organellar Delivery
[0717] After delivery to and entry into a targeted cell, a minicell
may be designed so as to be degraded, thereby releasing the
therapeutic agent it encapsulates into the cytoplasm of the cell.
The minicell and/or therapeutic agent may include one or more
organellar delivery elements, which targets a protein into or out
of a specific organelle or organelles. For example, the ricin A
chain can be included in a fusion protein to mediate its delivery
from the endosome into the cytosol. Additionally or alternatively,
delivery elements for other organelles or subcellular spaces such
as the nucleus, nucleolus, mitochondria, the Golgi apparatus, the
endoplasmic reticulum (ER), the cytoplasm, etc. are included
Mammalian expression constructs that incorporate organellar
delivery elements are commercially available from Invitrogen
(Carlsbad, Calif.: pShooter.TM. vectors). An H/KDEL (i.e.,
His/Lys-Asp-Glu-Leu sequence) may be incorporated into a fusion
protein of the invention, preferably at the carboxy-terminus, in
order to direct a fusion protein to the ER (see Andres et al., J.
Biol. Chem. 266:14277-142782, 1991; and Pelham, Trends Bio. Sci.
15:483-486, 1990).
[0718] Another type of organellar delivery element is one which
directs the fusion protein to the cell membrane and which may
include a membrane-anchoring element. Depending on the nature of
the anchoring element, it can be cleaved on the internal or
external leaflet of the membrane, thereby delivering the fusion
protein to the intracellular or extracellular compartment,
respectively. For example, it has been demonstrated that mammalian
proteins can be linked to i) myristic acid by an amide-linkage to
an N-terminal glycine residue, to ii) a fatty acid or
diacylglycerol through an amide- or thioether-linkage of an
N-terminal cysteine, respectively, or covalently to iii) a
phophotidylinositol (PI) molecule through a C-terminal amino acid
of a protein (for review, see Low, Biochem. J. 244: 1-13, 1987). In
the latter case, the PI molecule is linked to the C-terminus of the
protein through an intervening glycan structure, and the PI then
embeds itself into the phopholipid bilayer; hence the term "GPI"
anchor. Specific examples of proteins know to have GPI anchors and
their C-terminal amino acid sequences have been reported (see Table
1 and FIG. 4 in Low, Biochemica et Biophysica Acta, 988:427-454,
1989; and Table 3 in Ferguson, Ann. Rev. Biochem., 57:285-320,
1988). Incorporation of GPI anchors and other membrane-targeting
elements into the amino- or carboxy-terminus of a fusion protein
can direct the chimeric molecule to the cell surface.
[0719] XIII.E. Minicell-Based Gene Therapy
[0720] The delivery of nucleic acids to treat diseases or disorders
is known as gene therapy (Kay et al., Gene Therapy, Proc. Natl.
Acad. Sci. USA 94:12744-12746, 1997). It has been proposed to use
gene therapy to treat genetic disorders as well as pathogenic
diseases. For reviews, see Desnick et al., Gene Therapy for Genetic
Diseases, Acta Paediatr. Jpn. 40:191-203, 1998; and Bunnell et al.,
Gene Therapy for Infectious Diseases, Clinical Microbiology Reviews
11:42-56, 1998).
[0721] Gene delivery systems use vectors that contain or are
attached to therapeutic nucleic acids. These vectors facilitate the
uptake of the nucleic acid into the cell and may additionally help
direct the nucleic acid to a preferred site of action, e.g., the
nucleus or cytoplasm (Wu et al., "Delivery Systems for Gene
Therapy," Biotherapy 3:87-95, 1991). Different gene delivery
vectors vary with regards to various properties, and different
properties are desirable depending on the intended use of such
vectors. However, certain properties (for example, safety, ease of
preparation, etc.) are generally desirable in most
circumstances.
[0722] The minicells of the invention may be used as delivery
agents for any therapeutic or diagnostic agent, including without
limitation gene therapy constructs. Minicells that are used as
delivery agents for gene therepay constructs may, but need not be,
targeted to specific cells, tissues, organs or systems of an
organism, of a pathogen thereof, using binding moieties as
described in detail elsewhere herein.
[0723] In order to enhance the effectiveness of gene delivery
vectors in, by way of non-limiting example, gene therapy and
transfection, it is desirable in some applications of the invention
to target specific cells or tissues of interest (targeted cells or
tissues, respectively). This increases the effective dose (the
amount of therapeutic nucleic acid present in the targeted cells or
tissues) and minimizes side effects due to distribution of the
therapeutic nucleic acid to other cells. For reviews, see Peng et
al., "Viral Vector Targeting," Curr. Opin. Biotechnol. 10:454-457,
1999; Gunzburg et al., "Retroviral Vector Targeting for Gene
Therapy," Cytokines Mol. Ther. 2:177-184, 1996.; Wickham,
"Targeting Adenovirus," Gene Ther. 7:110-114, 2000; Dachs et al.,
"Targeting Gene Therapy to Cancer: A Review," Oncol. Res.
9:313-325, 1997; Curiel, "Strategies to Adapt Adenoviral Vectors
for Targeted Delivery," Ann NY Acad. Sci. 886:158-171, 1999;
Findeis et al., "Targeted Delivery of DNA for Gene Therapy via
Receptors," Trends Biotechnol. 11:202-205, 1993.
[0724] Some targeting strategies make use of cellular receptors and
their natural ligands in whole or in part. See, for example,
Cristiano et al., "Strategies to Accomplish Gene Delivery Via the
Receptor-Mediated Endocytosis Pathway," Cancer Gene Ther., Vol. 3,
No. 1, pp. 49-57, January-Febuary 1996.; S. C. Philips,
"Receptor-Mediated DNA Delivery Approaches to Human Gene Therapy,"
Biologicals, Vol. 23, No. 1, pp. 13-6, March 1995; Michael et al.,
"Strategies to Achieve Targeted Gene Delivery Via the
Receptor-Mediated Endocytosis Pathway," Gene Ther., Vol. 1, No. 4,
pp. 223-32, July 1994; Lin et al., "Antiangiogenic Gene Therapy
Targeting The Endothelium-Specific Receptor Tyrosine Kinase Tie2,"
Proc. Natl. Acad. Sci., USA, Vol. 95, pp. 8829-8834, 1998. Sudimack
et al., "Targeted Drug Delivery Via the Folate Receptor," Adv. Drug
Deliv., pp. 147-62, March 2000; Fan et al., "Therapeutic
Application of Anti-Growth Factor Receptor Antibodies," Curr. Opin.
Oncol., Vol. 10, No. 1, pp. 67-73, January 1998; Wadhwa et al.,
"Receptor Mediated Glycotargeting," J. Drug Target, Vol. 3, No. 2,
pp. 111-27, 1995; Perales et al., "An Evaluation of
Receptor-Mediated Gene Transfer Using Synthetic DNA-Ligand
Complexes," Eur. J. Biochem, Vol. 1, No 2, pp. 226, 255-66,
December 1994; Smith et al., "Hepatocyte-Directed Gene Delivery by
Receptor-Mediated Endocytosis," Semin Liver Dis., Vol. 19, No. 1,
pp. 83-92, 1999.
[0725] Antibodies, particularly single-chain antibodies, to surface
antigens specific for a particular cell type may also be used as
targeting elements. See, for example, Kuroki et al., "Specific
Targeting Strategies of Cancer Gene Therapy Using a Single-Chain
Variable Fragment (scFv) with a High Affinity for CEA," Anticancer
Res., pp. 4067-71, 2000; U.S. Pat. No. 6,146,885, to Dornburg,
entitled "Cell-Type Specific Gene Transfer Using Retroviral Vectors
Containing Antibody-Envelope Fusion Proteins"; Jiang et al., "In
Vivo Cell Type-Specific Gene Delivery With Retroviral Vectors That
Display Single Chain Antibodies," Gene Ther. 1999, 6:1982-7;
Engelstadter et al., "Targeting Human T Cells By Retroviral Vectors
Displaying Antibody Domains Selected From A Phage Display Library,"
Hum. Gene Ther. 2000, 11:293-303; Jiang et al., "Cell-Type-Specific
Gene Transfer Into Human Cells With Retroviral Vectors That Display
Single-Chain Antibodies," J. Virol 1998,72:10148-56; Chu et al.,
"Toward Highly Efficient Cell-Type-Specific Gene Transfer With
Retroviral Vectors Displaying Single-Chain Antibodies," J. Virol
1997, 71:720-5; Chu et al., "Retroviral Vector Particles Displaying
The Antigen-Binding Site Of An Antibody Enable Cell-Type-Specific
Gene Transfer," J. Virol 1995, 69:2659-63; and Chu et al., "Cell
Targeting With Retroviral Vector Particles Containing
Antibody-Envelope Fusion Proteins," Gene Ther. 1994, 1:292-9.
[0726] Minicells are used to deliver DNA-based gene therapy to
targeted cells and tissues. Double minicell transformants are used
not only to target a particular cell/tissue type (e.g. HIV-infected
T-cells) but are also engineered to fuse with and enter targeted
cells and deliver a protein-based toxin (e.g., antibiotic, or
pro-apoptotic gene like Bax), an antisense expression construct
(e.g., antisense to a transcription factor), or antisense
oligonucleotides (e.g., antisense to an anti-apoptotic gene such as
Bcl-2. The doubly-transformed minicells express not only these cell
death promoters, but also only target particular cells/tissues,
thus minimizing toxicity and lack of specificity of gene therapy
vectors. By "doubly-transformed" it is meant that the minicell
comprises 2 expression elements, one eubacterial, the other
eukaryotic. Alternatively, shuttle vectors, which comprise
eubacterial and eukaryotic expression elementsin one vector, may be
used.
[0727] Minicell-based gene therapy is used to deliver expression
plasmids that could correct protein expression deficiencies or
abnormalities. As a non-limiting example, minicell inhalants are
targeted to pulmonary alveolar cells and are used to deliver
chloride transporters that are deficient or otherwise material in
cystic fibrosis. Protein hormone deficiencies (e.g., dwarfism) are
corrected by minicell expression systems (e.g., growth hormone
expression in pituitary cells). Duchene's muscular dystrophy is
characterized by a mutation in the dystrophin gene; this condition
is corrected by minicell-based gene therapy. Angiogenesis treatment
for heart patients is made effective by FGF or VGEF-producing
minicells targeted to the heart. In this case, plasmid-driven
over-expression of these grown factors is preferred.
XIV. Therapeutic uses of Minicells
[0728] In addition to minicell-based gene therapy, minicells can be
used in a variety of therapeutic modalities. Non-limiting examples
of these modalities include the following applications.
[0729] XIV.A. Diseases and Disorders
[0730] Diseases and disorders to which the invention can be applied
include, by way of non-limiting example, the following.
[0731] Diseases and disorders that involve the respiratory system,
such as cystic fibrosis, lung cancer and tumors, asthma, pathogenic
infections, allergy-related diseases and disorders, , such as
asthma; allergic bronchopulmonary aspergillosis; hypersensitivity
pneumonia, eosinophilic pneumonia; emphysema; bronchitis; allergic
bronchitis bronchiectasis; cystic fibrosis; hypersensitivity
pneumotitis; occupational asthma; sarcoid, reactive airway disease
syndrome, interstitial lung disease, hyper-eosinophilic syndrome,
parasitic lung disease and lung cancer, asthma, adult respiratory
distress syndrome, and the like;
[0732] Diseases and disorders of the digestive system, such as
those of the gastrointestinal tract, including cancers, tumors,
pathogenic infections, colitis; ulcerative colitis, diverticulitis,
Crohn's disease, gastroenteritis, inflammatory bowel disease, bowel
surgery ulceration of the duodenum, a mucosal villous disease
including but not limited to coeliac disease, past infective
villous atrophy and short gut syndromes, pancreatitis, disorders
relating to gastroinstestinal hormones, Crohn's disease, and the
like;
[0733] Diseases and disorders of the skeletal system, such as
spinal muscular atrophy, rheumatoid arthritis, osteoarthritis,
osteoporosis, multiple myeloma-related bone disorder,
cortical-striatal-spinal degeneration, and the like;
[0734] Autoimmune diseases, such as Rheumatoid arthritis (RA),
multiple sclerosis (MS), Sjogren's syndrome, sarcoidosis, insulin
dependent diabetes mellitus (IDDM), autoimmune thyroiditis,
reactive arthritis, ankylosing spondylitis, scleroderma,
polymyositis, dermatomyositis, psoriasis, vasculitis, Wegener's
granulomatosis, Crohn's disease and ulcerative colitis amyotrophic
lateral sclerosis, multiple sclerosis, autoimmune gastritis,
systemic lupus erythematosus, autoimmune hemolytic anemia,
autoimmune neutropenia, systemic lupus erythematosus, graft vs.
host disease, bone marrow engraftment, some cases of Type I
diabetes, and the like;
[0735] Neurological diseases and disorders, such as depression,
bipolar disorder, schizophrenia, Alzheimer's disease, Parkinson's
disease, familial tremors, Gilles de la Tourette syndrome, eating
disorders, Lewy-body dementia, chronic pain and the like;
[0736] Pathological diseases and resultant disorders such as
bacterial infections such as infection by Escherichia, Shigella,
Salmonella; sepsis, septic shock, and bacteremia; infections by a
virus such as HIV, adenovirus, smallpox virus, hepatovirus, and the
like; and AIDS-related encephalitis, HIV-related encephalitis,
chronic active hepatitis, and the like;
[0737] Proliferative disease and disorders, such as acute
lymphoblastic leukemia, acute myelogenous leukemia, chronic
myelogenous leukemia, metastatic melanoma, Kaposi's sarcoma,
multiple myeloma, breast cancer, anal cancer, vulvar cancer, and
the like; and
[0738] Various diseases, disorders and traumas including, but not
limited to, apoptosis mediated diseases, inflammation, cerebral
ischemia, myocardial ischemia, aging, sarcoidosis, granulomatous
colitis, scleroderma, degenerative diseases, necrotic diseases,
alopecia, neurological damage due to stroke, diffuse cerebral
cortical atrophy, Pick disease, mesolimbocortical dementia,
thalamic degeneration, Huntington chorea, cortical-basal ganglionic
degeneration, cerebrocerebellar degeneration, familial dementia
with spastic paraparesis, polyglucosan body disease, Shy-Drager
syndrome, olivopontocerebellar atrophy, progressive supranuclear
palsy, dystonia musculorum deformans, Hallervorden-Spatz disease,
Meige syndrome, acanthocytic chorea, Friedreich ataxia, Holmes
familial cortical cerebellar atrophy,
Gerstmann-Straussler-Scheinker disease, progressive spinal muscular
atrophy, progressive balbar palsy, primary lateral sclerosis,
hereditary muscular atrophy, spastic paraplegia,
glomeralonephritis, chronic thyroiditis, Grave's disease,
thrombocytopenia, myasthenia gravis, psoriasis, peroneal muscular
atrophy, hypertrophic interstitial polyneuropathy, heredopathia
atactica polyneuritiformis, optic neuropathy, and
ophthalmoplegia.
[0739] A variety of diseases and disorders caused or exacerbated by
pathogens may be treated using the invention. For a comprehensive
description of pathogens and associated diseases and disorders, see
Zinsser Microbiology, 20th Ed., Joklik, ed.,
Appelton-Century-Crofts, Norwalk, Conn., 1992, and references cited
therein.
[0740] Minicells could also be used for replacement therapy (via
gene therapy) in a variety of conditions known to be caused by
protein or proteins that are either absent (e.g. Duchene's Muscular
Dystrophy), reduced in level (Dwarfism) or abberant (Sickle-cell
anemia).
[0741] For a comprehensive description of diseases and disorders
that may be treated using the invention, see The Merck Manual of
Diagnosis and Therapy, 17th Ed., Beers et al., eds.; published
edition, Merck and Co., Rahway, N.J., 1999; on-line edition,
Medical Services, Usmedsa, USHH,
http://www.merck.com/pubs/mmanual/, and references cited
therein.
[0742] XIV.B. Removal of Toxins and Pathogens by Selective
Absorption
[0743] When introduced into the bloodstream of an animal,
receptor-displaying minicells bind and absorb toxic compounds,
thereby removing such compounds from the general circulation. A
therapeutic benefit ensues as the bound toxic compound cannot
access the cells upon which it would otherwise exert its toxic
effect.
[0744] Minicells expressing receptors for toxic substances are
introduced IV in order to remove those toxins from the blood. One
non-limiting example is in the treatment of sepsis. In one
embodiment, a fusion protein is formed from the transmembrane
domain of the EGF receptor or toxR and a known soluble receptor for
LPS (lipopolysaccharide), such as the LBP (lipopolysaccharide
binding protein) or the extracellular domain of CD14 receptor
protein, both of which bind the LPS bacterial endotoxin. These
minicells inactivate LPS by initially binding to it and preventing
LPS binding to naturally occurring CD14 receptors on heart cells
and other cells involved in the endotoxic shock response.
Eventually, the minicell-LPS complex is cleared from the blood by
macrophages and other components of the immune system.
[0745] In another embodiment, minicells expressing receptors for
toxic drugs (e.g., morphine) are used to treat drug overdoses. In
other embodiments, minicells of the invention are used to express
receptors to venoms (e.g., snake venom) or poisons (e.g.,
muscarinic receptor expression for the treatment of muscarine
poisoning). In other embodiments, minicells of the invention
expressing EDGRs are used to clear the blood of toxins and other
undesirable compounds.
[0746] As another non-limiting example, minicells that bind
pathogens are used to treat disease. Minicells, and pathogens bound
thereto, may be ingested by human neutrophils and thus serve as an
adjuvant to therapeutic processes mediated by neutrophils (Fox et
al., Fate of the DNA in plasmid-containing Escherichia coli
minicells ingested by human neutrophils, Blood 69:1394-400, 1987).
In a related modality, minicells are used to bind compounds
required for the growth of a pathogen.
[0747] XIV.C. Antiviral Therapy
[0748] In one modality, minicells of the invention are used as
"sponges" for the selective absorption of any viral particle in the
body. Without being limited to the following examples, minicells
expression receptors or antibodies selectively directed against
viruses such as HIV, Hepatitis B and smallpox are used.
[0749] For the treatment of viremia, viruses are cleared from the
blood by absorption during dialysis or by IV injection of minicells
expressing targets for viral receptors. As the minicells interact
with blood-borne virus particles, there is an initial reduction of
host cell infection by virtue of the minicell-viral complexes that
are formed. Since viral particles attach to and/or enter the
minicell, they are not active because of the lack of machinery
needed for viral replication in the minicells. The virus infected
minicells are then cleared from the system by macrophages and
processed by the immune system.
[0750] Certain retroviruses that infect particular host cells
express viral proteins on the surfaces of the infected cells. HIV
infection of T-cells is one non-limiting example of this. The viral
protein, GP120, is expressed on the surfaces of infected T-cells
(Turner et al., Structural Biology of HIV, J. Mol. Biol. 285:1-32,
1999). Minicells expressing CD4 act as anti-GP120 minicells not
only to target virus particles in an infected patient, but also to
identify infected T-cells. It may be desirable to also express
co-receptors such as CCR5, CXR4 or ARD (Dragic, An overview of the
determinants of CCR5 and CXCR4 co-receptor function, J. Gen. Virol.
82:1807-1814, 2001). The minicells are then used to kill the
infected T-cells, or to inhibit viral replication and/or virion
assembly.
[0751] In another non-limiting example of anti-pathogen therapy,
minicells can by used to express bacterial surface antigens on
their surfaces that facilitate cellular uptake of the minicell by
intracellular pathogens such as Mycobacterium tuberculosis (the
causative agent of tuberculosis), Rickettsiae, or viruses. In this
"smart sponge" approach, selective absorption is accompanied by
internalization of the pathogen by minicells. Destruction of the
pathogen follows as a result of a combination of intraminicell
digestion of pathogens and/or by the eventual processing of the
virus-containing minicell by the cellular immune system of the
patient.
[0752] XIV. D. Antibacterial and Antiparasitic Applications
[0753] Minicells may be used to kill pathogenic bacteria,
protozoans, yeast and other fungi, parasitic worms, viruses and
other pathogens by mechanisms that either do or do not rely on
selective absorption. Antibiotics can be delivered to pathogenic
organisms after first being targeted by the proteins or small
molecules on the surfaces of the minicells that promote binding of
the minicells to the surfaces of the pathogen. Fusion or injection
of minicell contents into the pathogenic cell can result in the
death or disablement of the pathogen and thus lower the effective
dose of an antibiotic or gene therapeutic agent. Delivery of
antibiotics tethered to or encapsulated by the minicells will
reduce the effective dose of an antibiotic and will reduce its
elimination by the renal system. In the case of delivering
encapsulated molecules (e.g., antibiotics), purified/isolated
minicells expressing membrane-bound proteins for targeting can be
incubated with the molecules in vitro prior to administration. This
would be particularly applicable to the use of protoplast minicells
or poroplast minicells that have their outer membrane and cell wall
or outer membrane only removed, respectively, thus facilitating the
diffusion of the small molecule into the intact minicell.
[0754] Without being limited by the following example, minicells
can be use as antibacterial agents by expressing on the surfaces of
the minicells antigens, receptors, antibodies, or other targeting
elements that will target the minicell to the pathogenic organism
and facilitate the entry of plasmids, proteins, small molecules in
order to gain access to or entry into the organism. Antibiotics may
be encapsulated by minicells post isolation from the parent strain
so that the antibiotic will not be effective against the
minicell-producing bacteria itself. Since minicells are not able to
reproduce, the antibiotic will not be lethal to the minicell
delivery vehicle, but only to the targeted pathogen. In another
non-limiting example, lyosgenic factors e.g., complement may be
expressed on the surfaces of the minicells or encapsulated by same
as to promote lysis of the pathogen.
[0755] Minicells can also be engineered to express toxic proteins
or other elements upon binding to the pathogen. Induction of
minicell protein expression can be an event that is coincident with
targeting or triggered by minicell binding to the target pathogen,
thus making minicells toxic only when contact is made with the
pathogenic organism. Minicells can be engineered to express
fusion/chimeric proteins that are tethered to the membrane by
transmembrane domains that have signaling moieties on the
cytoplasmic surfaces of the minicells, such as kinases or
transcription factors. In one non-limiting example, a minicell
fusion membrane-bound protein could be expressed containing an
extracellular domain with a receptor, scFv, or other targeting
protein that binds to the pathogen. The second segment of the
chimera could be a transmembrane domain of a protein such as the
EGF receptor or ToxR (that would tether the fusion protein to the
membrane). Importantly, the cytoplasmic domain of the fusion
protein could be a kinase that phosphorylates a bacterial
transcription factor present in the minicell or could be fused to a
transcription factor that would be expressed on the cytoplasmic
surface of the minicell. The expression plasmid that was previously
introduced into the minicells would then be activated by promoters
utilizing the activated bacterial transcription factor pre-existing
in the minicells or that which may be introduced by the minicell.
Without being limited to the following example, the binding event
could be signaled by a fusion protein containing elements of a
receptor (e.g., EGF) or by an adhesion protein (e.g., an integrin)
that require oligomerization. In the example of the use of
integrins, bacterial or other transcription factors that also
require dimerization could be cloned as fusion proteins such that
the binding event would be signaled by a dimerization of two or
more identical recombinant chimeric proteins that have
association-dependent transcription factors tagged to the
C-terminus of the fusion protein. The minicells would only be toxic
when contact is made with the pathogen.
[0756] The proposed mechanism of induction coincident with
targeting is not limited to the antiparasitic uses of minicells but
can be used in other therapeutic situations where minicells are
used to express proteins of therapeutic benefit when directed
against eucaryotic cells of the organism (e.g., kill cancer cells
with protein toxins expressed only after binding of the minicell to
the cancer cell).
[0757] Transfer of DNA-containing plasmids or other expression
element, antisense DNA, etc. may be used to express toxic proteins
in the target cells or otherwise inhibit transcription and/or
translation in the pathogenic organism or would otherwise be toxic
to the cell. Without being limited by the following example,
minicells can be used to transfer plasmids expressing growth
repressors, DNAses, or other proteins or peptides (e.g.,
pro-apoptotic) that would be toxic to the pathogen.
[0758] XIV.E. Cancer Therapy
[0759] Fusion proteins expressed in minicells are used for cancer
therapy. In a non-limiting example, phage display antibody
libraries are used to clone single chain antibodies against
tumor-associated (tumor-specific) antigens, such as MUCH-1 or
EGFvIII. Fusion proteins expressing these antibodies, and further
comprising a single-pass transmembrane domain of an integral
membrane protein, are used to "present" the antibody to the surface
of the minicells. Injected minicells coated with anti-tumor
antibodies target the tumor and deliver pro-apoptotic genes or
other toxic substances to the tumor. The minicells are engulfed by
the tumor cells by processes such receptor-mediated endocytosis
(by, e.g., macrophages). By way of non-limiting example,
toxR-invasin could be expressed on the surfaces of the minicells to
promote endocytosis through the interaction between invasin and
beta2-integrins on the surfaces of the target cells.
[0760] Fusion proteins possessing viral fusion-promoting proteins
facilitate entry of the minicell to the tumor cell for gene therapy
or for delivery of chemotherapy bioactive proteins and nucleic
acids. In these and similar applications, the minicell may contain
separate eukaryotic and eubacterial expression elements, or the
expression elements may be combined into a single "shuttle
vector."
XV. Diagnostic Uses of Minicells
[0761] Minicells are transformed with plasmids expressing
membrane-bound proteins, such as receptors, that bind to specific
molecules in a particular biological sample such as blood, urine,
feces, sweat, saliva or a tissue such as liver or heart. Minicells
can also be used for delivery of therapeutic agents across the
blood-brain barrier to the brain. This modality is used, by way of
non-limiting example, for imaging purposes, and for the delivery of
therapeutic agents, e.g., anti-depressants, and agents for the
treatment of cancer, obesity, insomnia, schizophrenia, compulsive
disorders and the like. Recombinant expression systems are
incorporated into minicells where the plasmid-driven protein
expression construct could be the produce a single gene product or
a fusion protein, such as a soluble protein for the particular
ligand fused with a transmembrane domain of a different gene. The
fusion protein then acts as a membrane bound receptor for a
particular ligand or molecule in the sample. Conventional cloning
techniques (e.g., PCR) are used to identify genes for binding
proteins, or phage display is used to identify a gene for a
single-stranded variable antibody gene expressing binding protein
for a particular ligand. The protein product is preferably a
soluble protein. By constructing a plasmid containing this gene
plus the transmembrane domain of a known single-pass membrane
protein such as that of the EGF receptor, a fusion protein may be
expressed on the surfaces of the minicells as an integral membrane
protein with an extracellular domain that is preferably capable of
binding ligand.
[0762] In another type of fusion protein, the transmembrane domain
of the EGF receptor is fused to a known soluble receptor for a
particular ligand, such as the LBP (lipopolysaccharide binding
protein) or the extracellular domain of CD14 receptor protein, both
of which bind the bacterial endotoxin, LPS (lipopolysaccharide).
The LBP/EGF or CD14/EGF fusion protein is used to measure LPS in
the serum of patients suspected of sepsis.
[0763] The minicell system is used to express receptors such as
those of the EDG (endothelial cell differentiation gene) family
(e.g., EDG 1-9) that recognize sphingolipids such as
sphingosine-1-phosphate (S1P), sphingosylphosphoryl choline (SPC)
and the lysophospholipid, lysophosphatidic acid (LPA). Since these
proteins are 7-pass integral membrane proteins, no additional
transmembrane domains of another protein are needed, and the
receptor protein is thus not a fusion protein.
[0764] Truncated or mutant forms of a protein of interest are
useful in a diagnostic assay. For example, a protein that is an
ligand-binding enzyme can be altered so as to bind its substrate of
interest but can no longer convert substrate into product. One
example of this application of minicell technology is the
expression of a truncated or mutant lactic dehydrogenase which is
able to bind lactic acid, but is not able to convert lactic acid to
pyruvate. Similarly, hexokinase deriviatives are used in minicells
for glucose monitoring.
[0765] Minicells as diagnostic tools can be used either in vitro or
in vivo. In the in vitro context, the minicells are used in an
ELISA format or in a lateral flow diagnostic platform to detect the
presence and level of a desired analyte. A sample (tissue, cell or
body fluid sample) is taken and then tested in vitro. One advantage
of the minicell system in detecting substances in tissue, cells or
in body fluids is that the minicells can be used in vitro assays
where the minicell is labeled with either a radioactive or
fluorescent compound to aid in its detection in a an ELISA format
or lateral flow platform. Thus, the use of secondary antibody
detection systems is obviated.
[0766] As an in vivo diagnostic, minicells can be radiolabeled. One
method of labeling is to incubate minicells for a short time (about
8 hr) with a T.sub.1/2 tracer (e.g., Tn99M) that is useful for
detecting tumor metastases. The Tn99M accumulates in cells and
loads into minicells after isolation or into the parent bacteria
during growth phase. As Tn99M is oxidized by either the parent E.
coli strain or by the minicells after isolation, the Tn99M is
retained by the cell. Iodine-labled proteins may also be used
(Krown et al., TNF-alpha receptor expression in rat cardiac
myocytes: TNF-alpha inhibition of L-type Ca2+ transiets, FEBS
Letters 376:24-30, 1995).
[0767] One non-limiting example of in vivo detection of cancer
making use of radiolabeled minicells is the use of the minicells to
express chimeric membrane-bound single-chain antibodies against
tumor-specific antigens (TSA) expressed on malignant melanoma or
other transformed cells. Such TSAs include, but are not limited to,
the breast cancer associated MUC1 antigen and variant forms of the
EGFR (EGFvIII). By way of non-limiting example, minicells
expressing antibodies to melanoma cells can be injected (IV) into a
patient and then subjected to CAT scan of the lymphatic drainage in
order to determine if a metastasis has occurred. This diagnostic
technique obviates the need for lymph node dissection.
[0768] Another example of an in vivo diagnostic is to use the
minicell system to express antibodies against oxidized low-density
lipoproteins (LDL). Oxidized LDLs are associated with atherogenic
plaques. Radiolabeled minicells (prepared as above) are injected IV
into a person prior to nuclear imaging for image enhancement. MRI
image contrast enhancement is performed by preparing minicells
complexed (loaded) with contrast enhancers such as paramagnetic
relaxivity agents and magnetic susceptibility agents.
[0769] In diagnostic as well as other applications, minicells
preferentially detect a diagnostic marker, i.e., a marker
associated with a disease or disorder. A diagnostic marker is
statistically more like to occur in individuals suffering from a
disease than in those who are not diseased. Preferably, a
diagnostic marker directly causes or is produced during a disease;
however, the association may be no more than a correlation.
XVI. Drug Discovery (Screening) With Minicells
[0770] XVI.A. Assays
[0771] Minicells can be used in assays for screening
pharmacological agents. By way of non-limiting example, the
minicell system provides an environment for the expression of GPCRs
and studies of their ligand binding kinetics. Such GPCR's include
any member the Endothelial Differentiation Gene (EDG) receptor
family. GPCRs may participate in neoplastic cell proliferation,
angiogenesis and cell death. Small molecules that either activate
or inhibit the action of these GPCRs can be used in therapeutic
interaction.
[0772] Assays are performed to determine protein expression and
protein function. For example, the production of the protein can be
followed using protein .sup.35S-Met labeling. This is performed by
providing the cell only methionine that is labeled with .sup.35S.
The cells are treated with IPTG to induce protein expression, and
the .sup.35S-Met is incorporated into the protein. The cells are
then lysed, and the resulting lysates were electrophoresed on an
SDS gel and exposed to autoradiography film.
[0773] Another technique for assessing protein expression involves
the use of western blots. Antibodies directed to various expressed
proteins of interest have been generated and many are commercially
available. Techniques for generating antibodies to proteins or
polypeptides derived therefrom are known in the art (see, e.g.,
Cooper et al., Section III of Chapter 11 in: Short Protocols in
Molecular Biology, 2nd Ed., Ausubel et al., eds., John Wiley and
Sons, New York, 1992, pages 11-22 to 11-46). Standard western blot
protocols, which may be used to show protein expression from the
expression vectors in minicells and other expression systems, are
known in the art. (see, e.g., Winston et al., Unit 10.7 of Chapter
10 in: Short Protocols in Molecular Biology, 2nd Ed., Ausubel et
al., eds., John Wiley and Sons, New York, 1992, pages 10-32 to
10-35).
[0774] The amount of functional protein produced from a minicell
expression system is determined through the use of binding studies.
Ligands for the proteins of interest are used to show specific
binding in the minicell system. Radiolabeled ligand is incubated
with cells expressing the protein, in this case, a receptor for
TNF-alpha. The cells are then centrifuged and the radioactivity
counted in a scintillation counter. The amount of ligand that is
bound reflects the amount of functional protein that is present in
the sample.
[0775] By way of non-limiting example, the minicell system can be
made to express EDGRs for the purpose of screening combinatorial
chemistry libraries for molecules that enhance EDG activity. EDG
activity is assayed in the minicell environment in several ways.
One way is to crystallize minicells expressing an EDG protein (or
any membrane-bound protein of choice) and then measure changes in
the crystal structure to detect novel ligands. Circular dichroism
(CD), x-ray diffraction, electron spin resonance (EPR) or other
biophysical approaches are used to probe the structure of proteins
in the minicell context. Additionally or alternately, minicells are
produced that express not only the EDGR, but also express
G-proteins (i.e., double transformants). An assay system involving
GTP binding and hydrolysis is used to identify and assess which
small molecules in the combinatorial chemistry library serve as
activating ligands for EDG. The minicell expression system is used
in in vitro binding assays and in high throughput drug screenings.
The expression of mutant or truncated isoforms of proteins are used
for functional analyses in order to discover inactive or overactive
proteins for potential use in diagnostics or therapeutics.
[0776] XVI.B. High-Throughput Screening (HTS)
[0777] HTS typically uses automated assays to search through large
numbers of compounds for a desired activity. Typically HTS assays
are used to find new drugs by screening for chemicals that act on a
particular enzyme or molecule. For example, if a chemical
inactivates an enzyme it might prove to be effective in preventing
a process in a cell that causes a disease. High throughput methods
enable researchers to try out thousands of different chemicals
against each target very quickly using robotic handling systems and
automated analysis of results.
[0778] As used herein, "high throughput screening" or "HTS" refers
to the rapid in vitro screening of large numbers of compounds
(libraries); generally tens to hundreds of thousands of compounds,
using robotic screening assays. Ultra high-throughput Screening
(uHTS) generally refers to the high-throughput screening
accelerated to greater than 100,000 tests per day.
[0779] To achieve high-throughput screening, it is best to house
samples on a multicontainer carrier or platform. A multicontainer
carrier facilitates measuring reactions of a plurality of candidate
compounds simultaneously. Multi-well microplates may be used as the
carrier. Such multi-well microplates, and methods for their use in
numerous assays, are both known in the art and commercially
available.
[0780] Screening assays may include controls for purposes of
calibration and confirmation of proper manipulation of the
components of the assay. Blank wells that contain all of the
reactants but no member of the chemical library are usually
included. As another example, a known inhibitor (or activator) of
an enzyme for which modulators are sought, can be incubated with
one sample of the assay, and the resulting decrease (or increase)
in the enzyme activity determined according to the methods herein.
It will be appreciated that modulators can also be combined with
the enzyme activators or inhibitors to find modulators which
inhibit the enzyme activation or repression that is otherwise
caused by the presence of the known the enzyme modulator.
Similarly, when ligands to a sphingolipid target are sought, known
ligands of the target can be present in control/calibration assay
wells.
[0781] The minicells of the invention are readily adaptable for use
in high-throughput screening assays for screening candidate
compounds to identify those which have a desired activity, e.g.,
inhibiting an enzyme that catalyzes a reaction that produces an
undesirable compound, inhibiting function of a receptor independent
of ligand interference, or blocking the binding of a ligand to a
receptor therefor. The compounds thus identified can serve as
conventional "lead compounds" or can themselves be used as
therapeutic agents.
[0782] The methods of screening of the invention comprise using
screening assays to identify, from a library of diverse molecules,
one or more compounds having a desired activity. A "screening
assay" is a selective assay designed to identify, isolate, and/or
determine the structure of, compounds within a collection that have
a preselected activity. By "identifying" it is meant that a
compound having a desirable activity is isolated, its chemical
structure is determined (including without limitation determining
the nucleotide and amino acid sequences of nucleic acids and
polypeptides, respectively) the structure of and, additionally or
alternatively, purifying compounds having the screened activity).
Biochemical and biological assays are designed to test for activity
in a broad range of systems ranging from protein-protein
interactions, enzyme catalysis, small molecule-protein binding,
agonists and antagonists, to cellular functions. Such assays
include automated, semi-automated assays and HTS (high throughput
screening) assays.
[0783] In HTS methods, many discrete compounds are preferably
tested in parallel by robotic, automatic or semi-automatic methods
so that large numbers of test compounds are screened for a desired
activity simultaneously or nearly simultaneously. It is possible to
assay and screen up to about 6,000 to 20,000, and even up to about
100,000 to 1,000,000 different compounds a day using the integrated
systems of the invention.
[0784] Typically in HTS, target molecules are contained in each
well of a multi-well microplate; in the case of enzymes, reactants
are also present in the wells. Currently, the most widely
established techniques utilize 96-well microtiter plates. In this
format, 96 independent tests are performed simultaneously on a
single 8 cm.times.12 cm plastic plate that contains 96 reaction
wells. One or more blank wells contains all of the reactants except
the candidate compound. Each of the non-standard wells contain at
least one candidate compound.
[0785] These wells typically require assay volumes that range from
50 to 500 ul. In addition to the plates, many instruments,
materials, pipettors, robotics, plate washers and plate readers are
commercially available to fit the 96-well format to a wide range of
homogeneous and heterogeneous assays. Microtiter plates with more
wells, such as 384-well microtiter plates, are also used, as are
emerging methods such as the nanowell method described by Schullek
et al. (Anal Biochem., 30 246, 20-29, 1997).
[0786] In one modality, screening comprises contacting a
sphingolipid target with a diverse library of member compounds,
some of which are ligands of the target, under conditions where
complexes between the target and ligands can form, and identifying
which members of the libraries are present in such complexes. In
another non limiting modality, screening comprises contacting a
target enzyme with a diverse library of member compounds, some of
which are inhibitors (or activators) of the target, under
conditions where a product or a reactant of the reaction catalyzed
by the enzyme produce a detectable signal. In the latter modality,
inhibitors of target enzyme decrease the signal from a detectable
product or increase a signal from a detectable reactant (or
vice-versa for activators).
[0787] Minicells of the invention expressing and/or displaying a
protein are used for screening assays designed to identify agents
that modulate the activity of the target protein. Such assays
include competitive inhibition binding assays for high throughput
assays. Competitive inhibition assays include but are not limited
to assays that screen agents against a specific target protein to
identify agents that inhibit, interfere, block, or compete with
protein-ligand interactions, protein-protein interactions,
enzymatic activity, or function of a specific protein. Examples of
competitive inhibition include but are not limited to the
development of neutral inhibitors of the serine protease factor Xa
that were discovered using a high throughput screening assay using
a compound library (Carr et al, Neutral inhibitors of the serine
protease factor Xa, Bioorg Med Chem Lett 11, 2001), the design and
characterization of potent inhibitors for the human oxytocin
receptor (Seyer et al, Design, synthesis and pharmacological
characterization of a potent radio iodinated and photoactivatable
peptidic oxytocin antagonist, J Med Chem. 44:3022-30, 2001), and
the identification of non-peptide somatostatin antagonists of the
sst(3) protein (Thurieau et al, Identification of potent
non-peptide somatostatin antagonists with sst(3) selectivity, J Med
Chem. 44:2990-3000, 2001).
[0788] High throughput competitive inhibition assays are designed
to identify agents that inhibit a specific target protein. Such
assays include but are not limited to ones that measure enzymatic
activity, protein-ligand interactions, protein-protein interactions
and other functions of proteins. Minicells that express and/or
display a specific protein could be used in all types of
competitive inhibition assays.
[0789] One non-limiting example of high throughput competitive
inhibition screening using minicells for the purpose of this patent
involves the competitive inhibition of known ligands. The ligand is
attached to but not limited to a flourophore, fluorescent protein,
tags such as 6xHis tag or FLAG tag, chromophores, radiolabeled
proteins and molecules, binding moieties such as avidin and
strepavidin, voltage sensitive dies and proteins, bioluminescent
proteins and molecules, or fluorescent peptides. The target
protein, which binds the tagged ligand, is expressed and stably
displayed by the minicell. When the ligand is added to the minicell
solution the ligand binds to the target protein. Following a wash
the interaction is detected via the flourophore, fluorescent
protein, tag, or fluorescent peptide. The ligand-bound minicells
could either be centrifuged (taking advantage of the sedimentation
properties of the minicell particle) or immunoprecipitated with an
antibody against an antigen expressed on the minicell membrane or
the minicells can be adsorbed/fixed to a substrate such as a
standard 96 well plate. The competitive inhibition assay is carried
out by adding agents to the minicell mix either before, together or
after the ligand is added. Thus if the agent is a competitive
inhibitor of the ligand to the target protein the ligand will be
washed away from the minicell because it is not associated with the
target protein. The agent prevents binding and thus eliminated the
detection signal from the minicell.
[0790] Minicells of this invention are used in "functional
screening HTS assays". Functional screening assays are defined as
assays that provide information about the function of a specific
target protein. Functional assays screen agents against specific
target proteins to identify agents that either act as antagonist or
as an agonist against the protein. Functional assays require that
the target protein be in an environment that allows it to carry out
its natural function. Such functions include but are not limited to
G-proteins coupling with a GPCR, enzymatic activity such as
phosphorlyation or proteolysis, protein-protein interaction, and
transport of molecules and ions.
[0791] Functional assays screen agents against proteins which are
capable of natural function. Target proteins used in functional
studies must carry out a function that is measurable. Examples of
protein functions that are measurable include but are not limited
to the use of Fluorescent Resonance Energy Transfer (FRET) to
measure the G-protein coupling to a GPCR (Ruiz-Velasco et al.,
Functional expression and FRET analysis of green fluorescent
proteins fused to G-protein subunits in rat sympathetic neurons, J
Physiol. 537:679-692, 2001; Janetopoulos et al., Receptor-mediated
activation of heterotrimeric G-proteins in living cells, Science
291:2408-2411, 2001); Bioluminescence Resonance Energy Transfer
(BRET) to assay for functional ligand induced G-protein coupling to
a target GPCR (Menard, L. Bioluminescence Resonance Energy Transfer
(BRET): A powerful platform to study G-protein coupled receptors
(GPCR) activity in intact cells, Assay Development, Nov. 28-30,
2001), the use of florescent substrates to measure the enzymatic
activity of proteases (Grant, Designing biochemical assays for
proteases using fluorogenic substrates, Assay Development, Nov.
28-30, 2001); and the determination of ion channel function via the
use of voltage sensitive dies (Andrews et al, Correlated
measurements of free and total intracellular calcium concentration
in central nervous system neurons, Microsc Res Tech. 46:370-379,
1999).
[0792] One non-limiting example of high throughput functional
screening assay using minicells for the purpose of this patent
involves the functional coupling of GPCRs to their respective
G-protein. Upon ligand binding, voltage polarization, ion binding,
light interaction and other stimulatory events activate GPCRs and
cause them to couple to their respective G-protein. In a minicell,
both the GPCR and its respective G-proteins can be simultaneously
expressed. Upon activation of the GPCR the coupling event will
occur in the minicell. Thus by detecting this coupling in the
minicell, one could screen for agents that bind GPCRs to identify
antagonists and agonists. The antagonists are identified using
inhibition assays that detect the inhibition of function of the
GPCR. Thus the agent interacts with the GPCR in a way that it
inhibits the GPCR from being activated. The agonists are identified
by screening for agents that activate the GPCR in the absence of
the natural activator.
[0793] The detection of GPCR activation and coupling in a minicell
is accomplished by using systems that generate a signal upon
coupling. One non-limiting example involves the use of BRET or
FRET. These systems require that two fluorescent or bioluminescent
molecules or proteins be brought into close contact. Thus by
attaching one of these molecules or proteins to the GPCR and one to
the G-protein, they will be brought together upon coupling and a
signal will be generated. This signal can be detected using
specific detection equipment and the coupling event can be
monitored. Thus the function of the GPCR can be assayed and used in
functional assays in minicells.
[0794] Another non-limiting functional assay for GPCRs and other
proteins in minicells involves the use of transcription factors.
Many bacterial transcription factors and eukaryotic transcription
factors require dimerization for activation. By attaching one
subunit of a transcription factor to a GPCR and the other subunit
to a G-protein, the subunits will dimerize upon coupling of the
GPCR to the G-protein because they will be brought into close
contact. The dimerized transcription factor will then be activated
and will act on its target episomal DNA. In the minicell system the
episomal DNA target will be a plasmid that encodes for proteins
that provide a signal for detection. Such proteins include but are
not limited to luciferase; green fluorescent protein (GFP), and
derivatives thereof such as YFP, BFP, etc.; alcohol dehydrogenase,
and other proteins that can be assayed for expression. The
activation of the GPCR will result in coupling and activation of
the transcription factor. The transcription factor will then induce
transcription and translation of specific detector proteins. Thus
the activation of the GPCR will be monitored via the expression of
the detector protein.
[0795] In another modality, the transcription factor can inhibit
expression in the minicell system and thus allowing for the
screening of constitutively active GPCRs and proteins. For example
if the GPCR were constitutively active then the transcription
factor to use would be one that inhibits transcription and
translation. Thus agents could be screened against the
constitutively active GPCR to identify agents that caused the
constitutively active GPCR to uncouple. The uncoupling will result
in the inactivation of the transcription factor. The inhibition
caused by the transcription factor will be removed and
transcription and translation will occur. Thus a detectable protein
will be made and a signal will be received.
[0796] The transcription dimerization assay can be used for any
protein function that involves a protein-protein interaction,
protein-ligand interaction and protein-drug interaction. Thus any
assay involving such interactions can be carried out in the
minicell.
[0797] Another non-limiting functional screening assay involves the
use of enzymatic function to screen for functionality. In this
modality the receptor or other protein performs a specific
enzymatic function. This function is then carried out in the
minicell and monitored using biochemical and other techniques. For
example if the target protein was a protease then fluorescent
peptides with the cleavage site of the protease could be used to
monitor the activity of the protease. If the protease was
functioning then the peptide would be cleaved and the fluorescents
would change. Thus agents can be screened against the protease in
the minicell system and the fluorescents can be monitored using
specific detection systems. In another non-limiting example, a
membrane-bound enzyme such as sphingomyelinase could be expressed
in minicells and the minicell particles adsorbed to a standard
substrate such as a 96 well plate. The enzymatic activity could be
assessed by a standard in vitro assay involving the release of
product (phosphocholine) (e.g., Amplex.TM. kit A-12220 sold by
Molecular Probes). Sphingomyelinase inhibitors could be screened by
measuring the reduction of phosphocholine production in the well
when presented with substrate (sphingomyelin) in a coupled
fluorescence assay.
[0798] Another non-limiting example of minicells used for
functional assays involves the screening of agonists/antagonists
for ion channels. In this example the calcium channel, SCaMPER, is
encoded on a poycistronic episomal plasmid, which also encodes for
a luminescent soluble protein, aequorin. In this assay, the
minicell will contain aequorin proteins in its cytoplasm and
SCaMPER proteins expressed on the minicell membrane. Thus upon
activation of SCaMPER by its ligand, SPC, or by an analog thereof,
calcium will flow into the minicell and will be bound by the
aequorin which will luminescence. Thus a detection signal for the
functional activation of the calcium channel is obtained.
[0799] Minicell can also be employed for expression of target
proteins and the preparation of membrane preparations for use in
screening assays. Such proteins include but are not limited to
receptors (e.g., GPCRs, sphingolipid receptors, neurotransmitter
receptors, sensory receptors, growth factor receptors, hormone
receptors, chemokine receptors, cytokine receptors, immunological
receptors, and compliment receptors, FC receptors), channels (e.g.,
potassium channels, sodium channels, calcium channels.), pores
(e.g., nuclear pore proteins, water channels), ion and other pumps
(e.g., calcium pumps, proton pumps), exchangers (e.g.,
sodium/potassium exchangers, sodium/hydrogen exchangers,
potassium/hydrogen exchangers), electron transport proteins (e.g.,
cytochrome oxidase), enzymes and kinases (e.g., protein kinases,
ATPases, GTPases, phosphatases, proteases.), structural/linker
proteins (e.g., Caveolins, clathrin), adapter proteins (e.g., TRAD,
TRAP, FAN), chemotactic/adhesion proteins (e.g., ICAM11, selectins,
CD34, VCAM-1, LFA-1, VLA-1), and chimeric/fusion proteins (e.g.,
proteins in which a normally soluble protein is attached to a
transmembrane region of another protein). In such assays the
membrane preparations are used to screen for agents that are either
antagonists or agonists. These assays use various formats including
but not limited to competitive inhibition.
[0800] The format for the screening of minicells includes but is
not limited to the use of test tubes, 6 well plates, 12 well
plates, 24 well plates, 96 well plates, 384 well plates, 1536 well
plates, and other microtiter well plates. In these systems the
minicells can be immobilized, attached, bound, or fused with the
above test tubes or plates. The minicells can also be free in
solution for use in tubes and plates. The detection systems for the
minicell assay include but are not limited to fluorescent plate
readers, scintillation counters, spectrophotometers, Viewlux CCD
Imager, Luminex, ALPHAQuest, BIAcore, FLIPR and F-MAT. Minicell
assays can be carried out with but not limited to techniques such
as manual handling, liquid handlers, robotic automated systems and
other formats.
[0801] XVI.C. Chemical Libraries
[0802] Developments in combinatorial chemistry allow the rapid and
economical synthesis of hundreds to thousands of discrete
compounds. These compounds are typically arrayed in moderate-sized
libraries of small organic molecules designed for efficient
screening. Combinatorial methods, can be used to generate unbiased
libraries suitable for the identification of novel inhibitors. In
addition, smaller, less diverse libraries can be generated that are
descended from a single parent compound with a previously
determined biological activity. In either case, the lack of
efficient screening systems to specifically target therapeutically
relevant biological molecules produced by combinational chemistry
such as inhibitors of important enzymes hampers the optimal use of
these resources.
[0803] A combinatorial chemical library is a collection of diverse
chemical compounds generated by either chemical synthesis or
biological synthesis, by combining a number of chemical "building
blocks," such as reagents. For example, a linear combinatorial
chemical library, such as a polypeptide library, is formed by
combining a set of chemical building blocks (amino acids) in a
large number of combinations, and potentially in every possible
way, for a given compound length (i.e., the number of amino acids
in a polypeptide compound). Millions of chemical compounds can be
synthesized through such combinatorial mixing of chemical building
blocks.
[0804] A "library" may comprise from 2 to 50,000,000 diverse member
compounds. Preferably, a library comprises at least 48 diverse
compounds, preferably 96 or more diverse compounds, more preferably
384 or more diverse compounds, more preferably, 10,000 or more
diverse compounds, preferably more than 100,000 diverse members and
most preferably more than 1,000,000 diverse member compounds. By
"diverse" it is meant that greater than 50% of the compounds in a
library have chemical structures that are not identical to any
other member of the library. Preferably, greater than 75% of the
compounds in a library have chemical structures that are not
identical to any other member of the collection, more preferably
greater than 90% and most preferably greater than about 99%. The
preparation of combinatorial chemical libraries is well known to
those of skill in the art. For reviews, see Thompson et al.,
Synthesis and application of small molecule libraries, Chem Rev
96:555-600, 1996; Kenan et al., Exploring molecular diversity with
combinatorial shape libraries, Trends Biochem Sci 19:57-64, 1994;
Janda, Tagged versus untagged libraries: methods for the generation
and screening of combinatorial chemical libraries, Proc Natl Acad
Sci USA. 91:10779-85, 1994; Lebl et al., One-bead-one-structure
combinatorial libraries, Biopolymers 37:177-98, 1995; Eichler et
al., Peptide, peptidomimetic, and organic synthetic combinatorial
libraries, Med Res Rev. 15:481-96, 1995; Chabala, Solid-phase
combinatorial chemistry and novel tagging methods for identifying
leads, Curr Opin Biotechnol. 6:632-9, 1995; Dolle, Discovery of
enzyme inhibitors through combinatorial chemistry, Mol Divers.
2:223-36, 1997; Fauchere et al., Peptide and nonpeptide lead
discovery using robotically synthesized soluble libraries, Can J
Physiol Pharmacol. 75:683-9, 1997; Eichler et al., Generation and
utilization of synthetic combinatorial libraries, Mol Med Today 1:
174-80, 1995; and Kay et al., Identification of enzyme inhibitors
from phage-displayed combinatorial peptide libraries, Comb Chem
High Throughput Screen 4:535-43, 2001.
[0805] Such combinatorial chemical libraries include, but are not
limited to, peptide libraries (see, e.g., U.S. Pat. No. 5,010,175,
Furka, Int. J. Pept. Prot. Res., 37:487-493 (1991) and Houghton, et
al., Nature, 354:84-88 1991). Other chemistries for generating
chemical diversity libraries can also be used. Such chemistries
include, but are not limited to, peptoids (PCT Publication No. WO
91/19735); encoded peptides (PCT Publication WO 93/20242); random
bio-oligomers (PCT Publication No. WO 92/00091); benzodiazepines
(U.S. Pat. No. 5,288,514); diversomers, such as hydantoins,
benzodiazepines and dipeptides (Hobbs, et al., Proc. Nat. Acad.
Sci. USA, 90:6909-6913 1993); vinylogous polypeptides (Hagihara, et
al., J. Amer. Chem. Soc. 114:6568 1992); nonpeptidal
peptidomimetics with .beta.-D-glucose scaffolding (Hirschmann, et
al., J. Amer. Chem. Soc., 114:9217-9218 1992); analogous organic
syntheses of small compound libraries (Chen, et al., J. Amer. Chem.
Soc., 116:2661 1994); oligocarbamates (Cho, et al., Science,
261:1303 1993); and/or peptidyl phosphonates (Campbell, et al., J.
Org. Chem. 59:658 1994); nucleic acid libraries (see, Ausubel,
Berger and Sambrook, all supra); peptide nucleic acid libraries
(see, e.g., U.S. Pat. No. 5,539,083); antibody libraries (see,
e.g., Vaughn, et al., Nature Biotechnology, 14(3):309-314 (1996)
and PCT/US96/10287); carbohydrate libraries (see, e.g., Liang, et
al., Science, 274:1520-1522 (1996) and U.S. Pat. No. 5,593,853);
small organic molecule libraries (see, e.g., benzodiazepines, Baum
C&E News, January 18, page 33 (1993); isoprenoids (U.S. Pat.
No. 5,569,588); thiazolidinones and metathiazanones (U.S. Pat. No.
5,549,974); pyrrolidines (U.S. Pat. Nos. 5,525,735 and 5,519,134);
morpholino compounds (U.S. Pat. No. 5,506,337); benzodiazepines
(U.S. Pat. No. 5,288,514); and the like.
[0806] Devices for the preparation of combinatorial libraries are
commercially available (see, e.g., 357 MPS, 390 MPS, Advanced Chem.
Tech, Louisville Ky., Symphony, Rainin, Woburn, Mass., 433A Applied
Biosystems, Foster City, Calif., 9050 Plus, Millipore, Bedford,
Mass.). In addition, numerous combinatorial libraries are
themselves commercially available (see, e.g., ComGenex, Princeton,
N.J., Asinex, Moscow, Ru, Tripos, Inc., St. Louis, Mo., ChemStar,
Ltd., Moscow, RU, 3D Pharmaceuticals, Exton, Pa., Martek Bio
sciences, Columbia, Md., etc.).
[0807] XVI.D. Measuring Enzymatic and Binding Reactions During
Screening Assays
[0808] Techniques for measuring the progression of enzymatic and
binding reactions in multicontainer carriers are known in the art
and include, but are not limited to, the following.
[0809] Spectrophotometric and spectrofluorometric assays are well
known in the art. Examples of such assays include the use of
colorimetric assays for the detection of peroxides, as disclosed in
Example 1(b) and Gordon, A. J. and Ford, R. A., The Chemist's
Companion: A Handbook Of Practical Data, Techniques, And
References, John Wiley and Sons, N.Y., 1972, Page 437.
[0810] Fluorescence spectrometry may be used to monitor the
generation of reaction products. Fluorescence methodology is
generally more sensitive than the absorption methodology. The use
of fluorescent probes is well known to those skilled in the art.
For reviews, see Bashford et al., Spectrophotometry and
Spectrofluorometry: A Practical Approach, pp. 91-114, IRL Press
Ltd. (1987); and Bell, Spectroscopy In Biochemistry, Vol. I, pp.
155-194, CRC Press (1981).
[0811] In spectrofluorometric methods, enzymes are exposed to
substrates that change their intrinsic fluorescence when processed
by the target enzyme. Typically, the substrate is nonfluorescent
and converted to a fluorophore through one or more reactions. As a
non-limiting example, SMase activity can be detected using the
Amplex.RTM. Red reagent (Molecular Probes, Eugene, Oreg.). In order
to measure sphingomyelinase activity using Amplex Red, the
following reactions occur. First, SMase hydrolyzes sphingomyelin to
yield ceramide and phosphorylcholine. Second, alkaline phosphatase
hydrolyzes phosphorylcholine to yield choline. Third, choline is
oxidized by choline oxidase to betaine. Finally, H.sub.2O.sub.2 in
the presence of horseradish peroxidase, reacts with Amplex Red to
produce the fluorescent product, Resorufin, and the signal
therefrom is detected using spectrofluorometry.
[0812] Fluorescence polarization (FP) is based on a decrease in the
speed of molecular rotation of a fluorophore that occurs upon
binding to a larger molecule, such as a receptor protein, allowing
for polarized fluorescent emission by the bound ligand. FP is
empirically determined by measuring the vertical and horizontal
components of fluorophore emission following excitation with plane
polarized light. Polarized emission is increased when the molecular
rotation of a fluorophore is reduced. A fluorophore produces a
larger polarized signal when it is bound to a larger molecule (i.e.
a receptor), slowing molecular rotation of the fluorophore. The
magnitude of the polarized signal relates quantitatively to the
extent of fluorescent ligand binding. Accordingly, polarization of
the "bound" signal depends on maintenance of high affinity
binding.
[0813] FP is a homogeneous technology and reactions are very rapid,
taking seconds to minutes to reach equilibrium. The reagents are
stable, and large batches may be prepared, resulting in high
reproducibility. Because of these properties, FP has proven to be
highly automatable, often performed with a single incubation with a
single, premixed, tracer-receptor reagent. For a eview, see
Owickiet al., Application of Fluorescence Polarization Assays in
High-Throughput Screening, Genetic Engineering News, 17:27,
1997.
[0814] FP is particularly desirable since its readout is
independent of the emission intensity (Checovich, W. J., et al.,
Nature 375:254-256, 1995; Dandliker, W. B., et al., Methods in
Enzymology 74:3-28, 1981) and is thus insensitive to the presence
of colored compounds that quench fluorescence emission. FP and FRET
(see below) are well-suited for identifying compounds that block
interactions between receptors and their ligands. See, for example,
Parker et al., Development of high throughput screening assays
using fluorescence polarization: nuclear receptor-ligand-binding
and kinase/phosphatase assays, J Biomol Screen 5:77-88, 2000.
[0815] Exemplary normal-and-polarized fluorescence readers include
the POLARION fluorescence polarization system (Tecan AG,
Hombrechtikon, Switzerland). General multiwell plate readers for
other assays are available, such as the VERSAMAX reader and the
SPECTRAMAX multiwell plate spectrophotometer (both from Molecular
Devices).
[0816] Fluorescence resonance energy transfer (FRET) is another
useful assay for detecting interaction and has been described
previously. See, e.g., Heim et al., Curr. Biol. 6:178-182, 1996;
Mitra et al., Gene 173:13-17 1996; and Selvin et al., Meth.
Enzymol. 246:300-345, 1995. FRET detects the transfer of energy
between two fluorescent substances in close proximity, having known
excitation and emission wavelengths. As an example, a protein can
be expressed as a fusion protein with green fluorescent protein
(GFP). When two fluorescent proteins are in proximity, such as when
a protein specifically interacts with a target molecule, the
resonance energy can be transferred from one excited molecule to
the other. As a result, the emission spectrum of the sample shifts,
which can be measured by a fluorometer, such as a fMAX multiwell
fluorometer (Molecular Devices, Sunnyvale Calif.).
[0817] Scintillation proximity assay (SPA) is a particularly useful
assay for detecting an interaction with the target molecule. SPA is
widely used in the pharmaceutical industry and has been described
(Hanselman et al., J. Lipid Res. 38:2365-2373 (1997); Kahl et al.,
Anal. Biochem. 243:282-283 (1996); Undenfriend et al., Anal.
Biochem. 161:494-500 (1987)). See also U.S. Pat. Nos. 4,626,513 and
4,568,649, and European Patent No. 0,154,734. An exemplary
commercially available system uses FLASHPLATE scintillant-coated
plates (NEN Life Science Products, Boston, Mass.).
[0818] The target molecule can be bound to the scintillator plates
by a variety of well known means. Scintillant plates are available
that are derivatized to bind to fusion proteins such as GST, His6
or Flag fusion proteins. Where the target molecule is a protein
complex or a multimer, one protein or subunit can be attached to
the plate first, then the other components of the complex added
later under binding conditions, resulting in a bound complex.
[0819] In a typical SPA assay, the gene products in the expression
pool will have been radiolabeled and added to the wells, and
allowed to interact with the solid phase, which is the immobilized
target molecule and scintillant coating in the wells. The assay can
be measured immediately or allowed to reach equilibrium. Either
way, when a radiolabel becomes sufficiently close to the
scintillant coating, it produces a signal detectable by a device
such as a TOPCOUNT NXT microplate scintillation counter (Packard
BioScience Co., Meriden Conn.). If a radiolabeled expression
product binds to the target molecule, the radiolabel remains in
proximity to the scintillant long enough to produce a detectable
signal.
[0820] In contrast, the labeled proteins that do not bind to the
target molecule, or bind only briefly, will not remain near the
scintillant long enough to produce a signal above background. Any
time spent near the scintillant caused by random Brownian motion
will also not result in a significant amount of signal. Likewise,
residual unincorporated radiolabel used during the expression step
may be present, but will not generate significant signal because it
will be in solution rather than interacting with the target
molecule. These non-binding interactions will therefore cause a
certain level of background signal that can be mathematically
removed. If too many signals are obtained, salt or other modifiers
can be added directly to the assay plates until the desired
specificity is obtained (Nichols et al., Anal. Biochem.
257:112-119, 1998).
[0821] XVI.E. Screening for Novel Antibiotics
[0822] As bacteria and other pathogens acquire resistance to known
antibiotics, there is an ongoing interest in identifying novel
antibiotics. See, e.g., Powell W A, Catranis C M, Maynard C A.
Synthetic antimicrobial peptide design. Mol Plant Microbe Interact
1995 September-October;8(5):792-4. Minicells can be used to assay,
identify and purify novel antibiotics to eubacteria. By way of
non-limiting example, a minicell that comprises a detectable
compound can be contacted with a candidate antibiotic to see if the
minicell is lysed by a candidate compound, which would release the
detectable compound from the interior of the minicell into
solution, this producing a signal that indicates that the candidate
antibiotic is effective at lysing bacteria. In such assays, the
detectable compound is such that it produces less or more of the
same signal, or a different signal, inside the minicell as compared
to in solution post-lysis. By way of non-limiting example, the
minicell could comprise a fluorescent compounds that, when
contacted with a second fluorescent compound in solution, produces
FRET.
[0823] XVI. F. Reverse Screening
[0824] In one version of minicell display, the invention provides
methods for screening libraries of minicells in which each minicell
comprises an expression element that encodes a few, preferably one,
membrane proteins in order to identify a membrane protein that
interacts with a preselected compound. By way of non-limiting
example, sequences encoding membrane proteins, fusion proteins, or
cytoplasmic proteins are cloned into an expression vector, either
by "shotgun" cloning or by directed cloning, e.g., by screening or
selecting for cDNA clones, or by PCR amplification of DNA
fragments, that encode a protein using one or more oligonucleotides
encoding a highly conserved region of a protein family. For a
non-limiting example of such techniques, see Krautwurst, D., et al.
1998. Identification of ligands for olfactory receptors by
functional expression of a receptor library. Cell 95:917-926. By
way of non-limiting example, a minicell expressing a receptor binds
a preselected ligand, which may be a drug. Various assays for
receptor binding, enzymatic activity, and channeling events are
known in the art and may include detectable compounds; in the case
of binding assays, competition assays may also be used
(Masimirembwa, C. M., et al. 2001. In vitro high throughput
screening of compounds for favorable metabolic properties in drug
discovery. Comb. Chem. High Throughput Screen. 4:245-263;
Mattheakis, L. C., and A. Saychenko. 2001. Assay technologies for
screening ion channel targets. Curr. Opin. Drug Discov. Devel.
4:124-134; Numann, R., and P. A. Negulescu. 2001. High-throughput
screening strategies for cardiac ion channels. Trends Cardiovasc.
Med. 11:54-59; Le Poul, E., et al. 2002. Adaptation of aequorin
functional assay to high throughput screening. J. Biomol. Screen.
7:57-65; and Graham, D. L., et al. 2001. Application of
beta-galactosidase enzyme complementation technology as a high
throughput screening format for antagonists of the epidermal growth
factor receptor. J. Biomol. Screen. 6:401-411).
[0825] Once a minicell has been identified by an assay and
isolated, DNA is prepared from the minicell. The cloned DNA present
in the minicell encodes the receptor displayed by the minicell.
Having been cloned, the receptor is used as a therapeutic target.
For example, the receptor is produced via recombinant DNA
expression and used in minicell-based or other assays to identify
and characterize known and novel compounds that are ligands,
antagonists and/or agonists of the cloned receptor. The ligands,
antagonists and agonists may be used as lead compounds and/or drugs
to treat diseases in which the receptor plays a role. In
particular, when the preselected ligand is a drug, diseases for
which that drug is therapeutic are expected to be treated using the
novel ligands, antagonists and agonists, or drugs and prodrugs
developed therefrom.
[0826] Preparations of minicells that express and secrete secretes
a soluble protein can be prepared in order to identify ligands,
including but not limited to small molecules, that interact with
the soluble protein. Soluble proteins include, but are not limited
to, known secreted or proteolytically cleaved proteins and
peptides, hormones and cytokines. In this format, minicells are
placed in, or adhered to, the wells of a microtiter multiwell
plate. A different compound or group of compounds is placed in each
well, along with any reagents necessary to generate or squelch a
signal corresponding to a change in the soluble protein produced by
the minicell. Such changes include, by way of non-limiting example,
conformational changes in the protein that may occur as a result of
binding of a ligand or otherwise. A well that generates the
appropriate signal contains a compound that causes a change in the
soluble protein.
[0827] It is also possible to carry out procedures such as the one
described in the immediately preceding paragraph "in reverse." In
this format, a known ligand, which may be a drug, is used to
identify soluble proteins that bind to the ligand/drug. Libraries
of minicells wherein each minicell secretes a different soluble
protein are prepared, and each type of minicell is placed into, or
adhered to the wall of, a well of a microtiter plate, along with
reagents for generating a signal when the ligand/drug binds to a
soluble protein. Minicells that generate the appropriate signal
comprise a cloned DNA that encodes a soluble protein that interacts
with the known ligand/drug. Once cloned, the soluble protein is
prepared and used as a therapeutic target in order to identify
known or novel compounds that bind thereto. When the preselected
ligand is a drug, diseases for which that drug is therapeutic are
expected to be treated using the known and novel compounds so
identified, or using drugs and prodrugs developed from such
compounds.
[0828] Mincells expressing known membrane and soluble proteins can
also be used to help characterize lead compounds and accelerate the
generation of drugs therefrom. In particular, such studies may be
used identify potentially detrimental interactions that might occur
upon in vivo administration, e.g.,, ADME/Tox screening (Ekins, S.,
et al. 2002. In silico ADME/Tox: the state of the art. J. Mol.
Graph. Model. 20:305-309; and Li, A., et al. 2002. Early ADME/Tox
studies and in silico screening. Drug Discov. Today 7:25-27).
[0829] By way of non-limiting example, a human receptor that is
known to be important for the normal functioning of a cell may be
expressed in mincells, and various chemical derivatives of a lead
compound can be tested to ensure that they do not bind to the
receptor, as such binding would be expected to have adverse effects
in vivo. As another example, an enzyme that degrades a drug, such
as a cytochrome P450, is expressed in mincells and used to examine
the susceptibility of a candidate drug to such degradation. The
cytochrome P450 family of enzymes is primarily responsible for the
metabolism of xenobiotics such as drugs, carcinogens and
environmental chemicals, as well as several classes of endobiotics
such as steroids and prostaglandins. Exemplary P450 cytochromes
involved in drug degradation include, but are not limited to,
CYP2D6 (cytochrome P4502D6, also known as debrisoquine
hydroxylase), CYP1A1, CYP1A2, CYP2A6, CYP2B6, CYP2C9, CYP2C18,
CYP2C19, CYP2D6, CYP2E1, CYP3A4 and CYP3A5.
[0830] XVI.G. Molecular Variants
[0831] In one aspect of the invention, minicells are used in
methods of screening to identify agents that improve, enhance, or
decrease the interaction of a protein with another compound. These
methods include, by way of non-limiting example, modification of
protein targets through directed or random mutagenic approaches to
identify critical interactions between a wild-type protein target
and a specific drug molecule. Information obtained from studies of
mutant proteins is used to specifically produce or modify a
therapeutic agent to interact more specifically and/or effectively
with the wild-type protein target, thus increasing the therapeutic
efficacy of the parental drug and/or decreasing non-specific,
potentially deleterious interactions. See, for example, Lietha, D.,
et al. 2001. Crystal structures of NK1-heparin complexes reveal the
basis for NK1 activity and enable engineering of potent agonists of
the MET receptor. EMBO J. 20:5543-5555; and Chen, Y. Z., et al. Can
an optimization/scoring procedure in ligand-protein docking be
employed to probe drug-resistant mutations in proteins? J. Mol.
Graph. Model. 19:560-570;Zhao, H. and F. H. Arnold. Combinatorial
protein design: Strategies for screening protein libraries. Current
Opinion in Structural Biology 7:480-485 (1997); and Carrupt P A, el
Tayar N, Karlen A, Testa B. Molecular electrostatic potentials for
characterizing drug-biosystem interactions. Methods Enzymol.
1991;203:638-77. Martin Y C. Computer-assisted rational drug
design. Methods Enzymol. 1991;203:587-613.
[0832] By way of non-limiting example, information obtained using
the methods of the invention may be in conjunction with x-ray
crystallographic structural determinations to characterize
receptor:ligand interactions (Muller, G. 2000. Towards 3D
structures of G protein-coupled receptors: a multidisciplinary
approach. Curr. Med. Chem. 7:861-888). By way of non-limiting
example, minicells may be used to display the family of molecular
variants to characterize the specific mutagenic changes on the
functional properties of the protein.
[0833] Studies of variant proteins can also be used to modify drugs
to fit natural variants of proteins, especially those associated
with pathogens. Pathogens such as viruses, including retroviruses
such as HIV, may acquire mutations that change a site where a drug
acts, thereby rendering the pathogen immune to the drug. Studies of
variant proteins can be used to quickly produce derivatives of a
drug that are active against a variant protein. See, for example,
Varghese J N, Smith P W, Sollis S L, Blick T J, Sahasrabudhe A,
McKimm-Breschkin J L, Colman P M. Drug design against a shifting
target: a structural basis for resistance to inhibitors in a
variant of influenza virus neuraminidase. Structure 1998 June
15;6(6):735-46; and Baldwin E T, Bhat T N, Liu B, Pattabiraman N,
Erickson J W. Structural basis of drug resistance for the V82A
mutant of HIV-1 proteinase. 78: Nat Struct Biol 1995
March;2(3):244-9.
[0834] XVI.H. Directed Evolution
[0835] The minicells and methods described herein can be used in
directed evolution. Unlike natural variation, directed evolution
generates new protein variants in vitro (see, e.g., Arnold, F. H.
and A. A. Violkov. Directed Evolution of Biocatalysts. Curr Op Chem
Biol 1999. 3:54-59). Amino acid substitutions can be introduced
into a protein of interest by mutating the gene encoding the
protein. Mutations are introduced by, e.g., replicating DNA in
mutator strains, by chemical mutagenesis or radiation-induced
mutagenesis (Drake, J. W., The Molecular Basis of Mutation,
Holden-Day, San Francisco, 1970). Other methods include error-prone
PCR and "domain shuffling" (Moore, G. L. and C. D. Maranas.
Modeling DNA Mutation and Recombination for Directed Evolution
Experiments. J. Ther. Biol. 2000. 205:483-503). In the latter
method, different regions of members of the same gene family are
recombined so that the inherent variability of members of the
family is used to produce novel "isoforms" of genes.
[0836] A group of variants is screened to select for those variants
which have the desired activity. The activity of the initial
variants that are so isolated may be inadequate for a given
application, but the process can be repeated using these initial
members to generate a second group of variants, or reiterated as
many times as is necessary to produce one or more variants having
the desired activity or characteristics.
[0837] XVI.I. Isolation and Characterization of Components of
Signal Tranduction Pathways
[0838] In one version of minicell display, the invention provides
methods for screening libraries of minicells, in which each
minicell comprises a preselected component of a signal transduction
pathway, in order to identify soluble and membrane proteins that
interact with the preselected component. By way of non-limiting
example, a plurality of minicells, each of which displays the same
G-protein-coupled receptor (GPCR), is used to prepare a minicell
library in which a different G-protein encoding sequence is present
and expressed in each minicell. Minicells comprising a G-protein
that interacts with the GPCR are identified, e.g., via
transactivation assays described in Example 18. Once a minicell has
been identified by an assay and isolated, DNA is prepared from the
minicell. The cloned DNA present in the minicell encodes a
G-protein that interacts with the GPCR of the displayed by the
minicells of the library. Having been cloned, the G-protein is used
as a therapeutic target that can be used in screening assays to
identify novel lead compounds and drugs that interfere or alter the
activity of the GPCR. In particular, when the GPCR of the minicell
library is known to be a therapeutic target for a specific disease,
it is expected that compounds that interfere or alter the activity
of a G-protein that interacts with the GPCR will be or lead to
therapeutics for that specific disease.
[0839] In addition to G-protein signal transduction pathways, other
non-limiting examples of signal tranduction pathways include the
MAPK pathway, the SAPK pathway, the p38 pathway and/or the
ceramide-mediated stress response pathway. See Zhang, W., and L. E.
Samelson. 2000. The role of membrane-associated adaptors in T cell
receptor signalling. Semin. Immunol. 12:35-41; Liebmann, C. 2001.
Regulation of MAP kinase activity by peptide receptor signalling
pathway: paradigms of multiplicity. Cell Signal. 13:777-785; Lee,
Jr., J. T., and J. A. McCubrey. 2002. The Raf/MEK/ERK signal
transduction cascade as a target for chemotherapeutic intervention
in leukemia. Leukemia. 16:486-507; Tibbles, L. A., and J. R.
Woodgett. 1999. The stress-activated protein kinase pathways. Cell
Mol. Life Sci. 55:1230-1254; Rao, K. M. 2001. MAP kinase activation
of macrophages. J. Leukoc. Biol. 69:3-10; Pelech, S. L., and D. L.
Charest. 1995. MAP kinase-dependent pathways in cell cycle control.
Prog. Cell Cycle Res. 1:33-52; Lee, S. H., et al. 2001.
BetaPix-enhanced p38 activation by Cdc42/Rac/PAK/MKK3/6-mediated
pathway. Implication in the regulation of membrane ruffling. J.
Biol. Chem. 276:25066-25072; Ono, K., et al. 2000. The p38 signal
transduction pathway Activation and function. Cellular Signalling
12:1-13; You, A. 2001. Differentiation, apoptosis, and function of
human immature and mature myeloid cells: intracellular signaling
mechanism. Int. J. Hematol. 73:438-452; Johnson, D. I. 1999. Cdc42:
An essential Rho-type GTPase controlling eukaryotic cell polarity.
Microbiol. Mol. Biol. Rev. 63:54-105; Williams, J. A. 2001.
Intracellular signaling mechanisms activated by
cholecystokinin-regulating synthesis and secretion of digestive
enzymes in pancreatic acinar cells. Annu. Rev. Physiol. 63:77-97;
Mathias, S., et al. 1998. Signal trasduction of stress via
ceramide. Biocehm J. 335:465-480; and Hannun, Y. A., et al. 2000.
Ceramide in the eukaryotic stress response. Trends Cell Biol.
10:73-80.
XVII. Determining the Structures of Membrane Proteins
[0840] Three-dimensional (3D) structures of proteins may be used
for drug discovery. However, GPCRs and other membrane proteins
present challenging problems for 3D structure determination.
Muller, Towards 3D structures of G protein-coupled receptors: a
multidisciplinary approach. (Review), Curr Med Chem 2000 pp.861-88;
Levy et al., Two-dimensional crystallization on lipid layer: A
successful approach for membrane proteins, J Struct Biol 1999 127,
44-52. Although the three-dimensional structures of hundreds of
different folds of globular proteins have been determined, fewer
than 20 different integral membrane protein structures have been
determined. There are many reasons for this. Extracting membrane
proteins from the membrane can easily disrupt their native
structure, and membrane proteins are notoriously difficult to
crystallize.
[0841] Some membrane proteins readily form two-dimensional crystals
in membranes and can be used for structure determination using
electron diffraction spectroscopy (ED) instead of x-ray
crystallography. This is the technique that was used to determine
the structure of bacteriorhodopsin (see below).
[0842] Nuclear magnetic resonance (NMR) is an alternative method
for determining membrane protein structure, but most membrane
proteins are too large for high-resolution NMR at the present state
of the art. Furthermore, membrane proteins require special
conditions for NMR, e.g. deuterated lipids must be used to avoid
confusing the signal of the protein protons with the noise of
membrane lipid protons.
[0843] Membrane protein for which structures have been determined
include photosynthetic reaction center, porin, porin OmpF, plant
light-harvesting complex (chlorophyll a-b binding protein),
bacterial light-harvesting complex, cytochrome c oxidase,
glycophorin A, the Sec A translocation ATPase of Bacillus subtilis,
and a bacterial potassium channel. For details, see: Weinkauf et
al., (2001): Conformational stabilization and crystallization of
the Sec A translocation ATPase from Bacillus subtilis. Acta
Crystallogr D Biol Crystallogr 57:559-565; Cowan et al., (1992):
Crystal structures explain functional properties of two E. coli
porins. Nature 358:727-33; Deisenhofer et al., (1984): X-ray
structure analysis of a membrane protein complex. Electron density
map at 3 A resolution and a model of the chromophores of the
photosynthetic reaction center from Rhodopseudomonas viridis. J Mol
Biol 180:385-98; Deisenhofer et al., (1985): Structure of the
protein subunits in the photosynthetic reaction centre of
Rhodopseudomonas viridis at 3 Angstroms resolution. Nature 318:618;
Doyle et al., (1998): The structure of the potassium channel:
molecular basis of K+conduction and selectivity. Science 280:69-77;
Henderson et al., (1990): Model for the structure of
bacteriorhodopsin based on high-resolution electron
cryo-microscopy. J Mol Biol 213:899-929; Iwata et al., (1998):
Complete structure of the 11-subunit bovine mitochondrial
cytochrome bc 1 complex. Science 281:64-71; Koepke et al., (1996):
The crystal structure of the light-harvesting complex II (B800-850)
from Rhodospirillum molischianum. Structure 4:581-97; Kuhlbrandt et
al., (1994): Atomic model of plant light-harvesting, complex by
electron crystallography. Nature 367:614-21; Lemmon et al., (1992):
Sequence specificity in the dimerization of transmembrane
alpha-helices. Biochemistry 31:12719-25; MacKenzie et al., (1997):
A transmembrane helix dimer: structure and implications. Science
276:131-3; McDermott et al., (1995): Crystal structure of an
integral membrane light-harvesting complex from photosynthetic
bacteria, Nature 374:517-21; Michel (1982): Three-dimensional
crystals of a membrane protein complex. The photosynthetic reaction
centre from Rhodopseudomonas viridis. J Mol Biol 158:567-72;
Tsukihara et al., (1996): The whole structure of the 13-subunit
oxidized cytochrome c oxidase at 2.8 A. Science 272:1136-44; and
Weiss et al., (1991): The structure of porin from Rhodobacter
capsulatus at 1.8 A resolution. FEBS Lett 280:379-82. Table 5,
which is based upon Preusch et al. (1998) as revised by White &
Wimley (1999), lists membrane proteins whose crystallographic
structures have been determined.
5TABLE 5 Structural Data Regarding Membrane Proteins PROTEIN
REFERENCES MONOTOPIC MEMBRANE PROTEINS Portaglandin H2 synthase-1.
Sheep. 3.5 .ANG. Picot et al. (1994) Cyclooxygenase-2. Mus
Musculus. 3.0 .ANG. Kurumbail et al. (1996) Squalene-hopene
cyclase. Alicyclobacillus acidocaldarius. Wendt et al. (1999) 2.0
.ANG. TRANSMEMBRANE PROTEINS Bacterial Rhodopsins (Halobacterium
salinarium) Bacteriorhodopsin (BR) 2D xtals. EM. 3.5 .ANG.
Grigrorieff et al. (1996) 2D xtals. EM. 3.0 .ANG. Kimura et al.
(1997) 3D xtals. X-ray. 2.5 .ANG. Pebay-Peyroula et al. (1997) 3D
xtals. X-ray. 1.9 .ANG. Belhrhali et al. (1999) 3D xtals. X-ray 2.1
.ANG. K intermediate Edman et al. (1999) 3D xtals. X-ray. 2.3 .ANG.
Luecke et al. (1998) 3D xtals. X-ray. 1.55 .ANG. Luecke et al.
(1999) 3D xtals. X-ray. D96N mutant (BR) 1.80 .ANG.. Luecke et al.
(1999) 3D xtals. X-ray. D96N mutant (M) 2.00 .ANG. 3D xtals. X-ray.
2.9 .ANG. Essen et al. (1998) Halorhodopsin (HR) 3D xtals. Xray.
1.8 .ANG. Kolbe et al. (2000) G PROTEIN-COUPLED RECEPTORS
Rhodopsin. Bovine Rod Outer Segment. 2.8 .ANG. Palczewski et al.
(2000) Photosynthetic Reaction Centers Rhodopseudomonas virdis. 2.3
.ANG. Deisenhofer et al. (1985) Rhodobacter sphaeroides. 3.0 .ANG.
Yeates et al. (1987) Rhodobacter sphaeroides. 3.1 .ANG. Chang et
al. (1991) Light Harvesting Complexes Rhodopseudomonas acidophila.
2.5 .ANG. McDermott et al. (1995) Rhodospirillum molischianum. 2.4
.ANG. Koepke et al. (1996) Photosystems Photosystem I.
Synechococcus elongates 4.0 .ANG. Schubert et al. (1997)
Photosystem II. Synechocoocus elongates 3.8 .ANG. Zouni et al.
(2001) Beta-Barrel Membrane Proteins-Multimeric (Porins and
Relatives) Porin. Rhodobacter capsulatus. 1.8 .ANG. Weiss &
Schulz (1992) Porin. Rhodopeudomonas blastica 1.96 .ANG. Kreutsch
et al. (1994) OmpF. E. coli. 2.4 .ANG. Cowan et al. (1992) PhoE. E.
coli. 3.0 .ANG. Cowan et al. (1992) Maltoporin. Salmonella
typhimurium. 2.4 .ANG. Meyer et al. (1997) Maltoporin. E. coli 3.1
.ANG. Schirmer et al. (1995) Beta-Barrel Membrane
Proteins-Monomeric/Dimeric TolC outer membrane protein. E. coli 2.1
.ANG. Protein is a Koronakis et al. (2000) trimer, each
contributing 4 strands to a single barrel. OmpA. E. coli. 2.5 .ANG.
Pautsch & Schulz (1998) OmpA E. coli. By NMR, in DPC micelles
Arora et al. (2001) OmpX. E. coli. 1.9 .ANG. Vogt & Schulz
(1990) OMPLA (outer membrane phospholipase A) E. coli. 2.1 .ANG..
Snijder et al. (1999) monomer (1QD5) and dimer (1QD6) FhuA. E.
coli. 2.5 .ANG. Ferguson et al. (1998); Lambert et al., 1999 FhuA +
ferrichrome-iron. E. coli. 2.7 .ANG. Buchanan et al. (1999) FepA.
E. coli. 2.4 .ANG. Ferguson et al. (1999) Glycophorin A.humanm.
MacKenzie et al. (1997) Non-constitutive Toxins, etc.
Alpha-hemolysin. Staphylococcus aureus. 1.9 .ANG. Song et al.
(1996) LukF. Staphylococcus aureus. 1.9 .ANG. Olson et al. (1999)
Ion Channels KcsA Potassium, H.sup.+ gated. Streptomyces lividans.
3.2 .ANG. Doyle et al. (1998) MscL Mechanosensitive. Mycobacterium
tuberculosis. Chang et al. (1998) 3.5 .ANG. Other Channels AQP1 -
aquaporin water channel. Red blood cell. Murata et al. (2000)
Electron crystallography in membrane plane. 3.8 .ANG. AQP1 - In
vitreous ice by electron microscopy. 3.7 .ANG. Ren et al. (2000)
GipF - glycerol facilitator channel. E. coli. 2.2 .ANG. Fu et al.
(2000) P-type ATPase Calcium ATPase. Sarcoplasmic reticulum.
Rabbit. 2.6 .ANG. Toyoshima et al. (2000) Respiratory Proteins
Fumerate Reductase Complex. Escherichia coli. 3.3 .ANG. Iverson et
al. (1999) Fumerate Reductase Complex. Wolinella succinogenes
Lancaster et al. (1999) 2.2 .ANG. ATP synthase (F.sub.1c.sub.10).
S. cerevisiae. 3.9 .ANG.. X-ray Stock et al. (1999) structure is a
C alpha model derived from composite of 1BMF, 1A91 & 1AQT
Cytochrome C Oxidases aa.sub.3 bovine heart mitochondria. 2.8 .ANG.
Tsukihara et al. (1996) aa.sub.3Paracoccus denitrificans. 2.8 .ANG.
Iwata et al. (1995) ba.sub.3 from T. thermophilus. 2.4 .ANG.
Soulimane et al. (2000) Cytochrome bc.sub.1 Complexes Bovine Heart
Mitochondria (5 subunits). 2.9 .ANG. Xia et al. (1997) Chicken
Heart Mitochondria. 3.16 .ANG. Zhang et al. (1998) Bovine Heart
Mitochondria (11 subunits). 2.8-3.0 .ANG.. Iwata et al. (1998) S.
cerevisiae (yeast, 9 subunits). 2.3 .ANG. Hunte et al. (2000)
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XVIII. Biosensors AND Environmental Applications
[0899] XVIII.A. Minicell-Based Biosensors
[0900] The present invention is directed to a device that comprises
a sensor adapted to detect one or more specific health and/or
nutrition markers in a subject or in the environment. The device
may also signal the caretaker, the subject, or an actuator of the
occurrence. The sensor comprises a biosensor. As used herein, the
term "biosensor" is defined as a component comprising one or more
binding moities being adapted to detect a ligand found in one or
more target pathogenic microorganisms or related biomolecules.
[0901] Generally, biosensors function by providing a means of
specifically binding, and therefore detecting, a target
biologically active analyte. In this way, the biosensor is highly
selective, even when presented with a mixture of many chemical and
biological entities. Often the target biological analyte is a minor
component of a complex mixture comprising a multiplicity of
biological and other components. Thus, in many biosensor
applications, detection of target analytes occurs in the
parts-per-billion, parts-per-trillion, or even lower ranges
levels.
[0902] XVIII.A.1. Minicell-Based Biosensor Design
[0903] The biosensor of the present invention may comprise a
bio-recognition element, or molecular recognition element, that
provides the highly specific binding or detection selectivity for a
particular analyte. In a biosensor of the invention, the
bio-recognition element, or system, is a minicell displaying an
enzyme or sequence of enzymes; an antibody or antibody derivative;
a membrane receptor protein; or the like, and generally functions
to interact specifically with a target biological analyte. The
bio-recognition element is responsible for the selective
recognition of the analyte and the physico-chemical signal that
provides the base for the output signal. The expressed protein or
molecule does not need to be a naturally occurring membrane bound
protein but could be a soluble protein or small molecule thethered
to the minicell by, for example, a transmembrane domain of another
protein such as the EGFR or ToxR.
[0904] Biosensors may include biocatalytic biosensors, and
bioaffinity biosensors. In biocatalytic biosensor embodiments, the
bio-recognition element minicell is "biocatalytic," e.g., displays
an enzyme. In biocatalytic biosensors, the selective binding sites
"turn over" (i.e., can be used again during the detection process),
resulting in a significant amplification of the input signal.
Biocatalytic sensors such as these are generally useful for
real-time, continuous sensing.
[0905] Bioaffinity sensors are generally applicable to bacteria,
viruses, toxins and other undesirable compounds and include
chemoreceptor-based biosensors and/or immunological sensors (i.e.,
immunosensors). Chemoreceptors are complex biomolecular
macroassemblies responsible, in part, for a viable organism's
ability to sense chemicals in its environment with high
selectivity. Chemoreceptor-based biosensors comprise one or more
natural or synthetic chemoreceptors associated with a means to
provide a signal (visual, electrical, etc.) of the presence or
concentration of a target biological analyte. In certain
embodiments, the chemoreceptor may be associated with an electrode
(i.e., an electrical transducer) so as to provide a detectable
electrical signal. In the biosensors of the invention, minicells
displaying a receptor are used in place of chemoreceptors. The
minicell has many desired features of a viable cell, and performs
similar functions, but is more durable.
[0906] On the other hand, the bio-recognition elements of
immunosensors are generally antibodies or antibody derivatives. In
any case, bioaffinity biosensors are generally irreversible because
the receptor sites of the biosensor become saturated when exposed
to the target biological analyte. In a biosensor of the invention,
an immunosensor may be a minicell displaying an antibody or
antibody fragment.
[0907] Biocatalytic and bioaffinity biosensor systems are described
in more detail in Journal of Chromatography, 510 (1990) 347-354 and
in the Kirk-Othmer Encyclopedia of Chemical Technology, 4.sup.th
ed. (1992), John Wiley & Sons, NY, the disclosure of which is
incorporated by reference herein.
[0908] The biosensors of the present invention may detect
biologically active analytes related to impending (i.e., future
presentation of symptoms is likely) or current human systemic
disease states, including, but not limited to, pathogenic bacteria,
parasites (e.g., any stage of the life cycle, including eggs or
portions thereof, cysts, or mature organisms), viruses, fungi such
as Candida albicans, antibodies to pathogens, and/or microbially
produced toxins. Additionally, the biosensor may target
biologically active analytes related to impending or current
localized health issues, such as stress proteins (e.g., cytokines)
and interleukin 1-alpha that may precede the clinical presentation
of skin irritation or inflammation. In preferred embodiments, the
biosensor functions as a proactive sensor, detecting and signaling
the subject, a caretaker or medical personnel of the impending
condition prior to the presentation of clinical symptoms. This
allows time to administer prophylactic or remedial treatments to
the subject which can significantly reduce, if not prevent, the
severity and duration of the symptoms. Further, the sensor, by
detecting the presence of a target biological analyte in a sample
from the subject, may detect residual contamination on a surface,
such as skin or environmental surface, in contact with the
biosensor, and provide and appropriate signal.
[0909] The physico-chemical signal generated by the bio-recognition
element or elements may be communicated visually to the caretaker
or medical personnel (i.e., via a color change visible to the human
eye). Other embodiments may produce optical signals, which may
require other instrumentation to enhance the signal. These include
flourescence, bioluminesence, total internal reflectance resonance,
surface plasmon resonance, Raman methods and other laser-based
methods, such as LED or laser diode sensors. For example, exemplary
surface plasmon resonance biosensors are available as IBIS I and
IBIS II from XanTec Analysensysteme of Muenster, Germany, which may
comprise bioconjugate surfaces as bio-recognition elements.
Alternatively, the signal may be processed via an associated
transducer which, for example, may produce an electrical signal
(e.g., current, potential, inductance, or impedance) that may be
displayed (e.g., on a readout such as an LED or LCD display) or
which triggers an audible or tactile (e.g., vibration) signal or
which may trigger an actuator, as described herein. The signal may
be qualitative (e.g., indicating the presence of the target
biological analyte) or quantitative (i.e., a measurement of the
amount or concentration of the target biological analyte). In such
embodiments, the transducer may optionally produce an optical,
thermal or acoustic signal.
[0910] In any case, the signal may also be durable (i.e., stable
and readable over a length of time typically at least of the same
magnitude as the usage life of the device) or transient (i.e.,
registering a real-time measurement). Additionally, the signal may
be transmitted to a remote indicator site (e.g., via a wire, or
transmitter, such as an infrared or rf transmitter) including other
locations within or on the device or remote devices. Further, the
sensor, or any of its components, may be adapted to detect and/or
signal only concentrations of the target biological analyte above a
predefined threshold level (e.g., in cases wherein the target
biological analyte is normally present in the bodily waste or when
the concentration of the analyte is below a known "danger"
level).
[0911] The target analytes that the biosensors of the present
invention are adapted to detect may also be viruses. These may
include diarrhea-inducing viruses such as rotavirus, or other
viruses such as rhinovirus and human immunodeficiency virus (HIV).
An exemplary biosensor adapted to detect HIV is described in U.S.
Pat. Nos. 5,830,341 and 5,795,453, referenced above. The disclosure
of each of these patents is incorporated by reference herein.
Biosensors are adopted to use in different tissues; see, e.g., U.S.
Pat. No. 6,342,037; Roe et al. Jan. 29, 2002; Device having fecal
component sensor; and using different binding molecules, see, e.g.,
U.S. Pat. No. 6,329,160; Schneider et al. Dec. 11, 2001;
Biosensors.
[0912] When minicells are incorporated into a biosensor, they may
be immobilized in the biosensor by techniques known in the art such
as entrapment, adsorption, crosslinking, encapsulation, covalent
attachment, any combination thereof, or the like. Further, the
immobilization can be carried out on many different substrates such
as known the art. In certain preferred embodiments, the
immobilization substrate may be selected from the group of
polymer-based materials, hydrogels, tissues, nonwoven materials or
woven materials.
[0913] In certain embodiments, biosensor embodiments, may comprise,
be disposed on, or be operatively associated with a microchip, such
as a silicon chip, MEMs (i.e., micro electromechanical system)
device, or an integrated circuit. Microchip-based biosensors may be
known as "biochips". Regardless of the type of sensor, the
microchip may comprise a multiplicity of sensor components having
similar or different sensitivities, kinetics, and/or target
analytes (i.e., markers) in an array adapted to detect differing
levels or combinations of the analyte(s). Further, each sensor in
such an array may provide a different type of signal, including
those types disclosed herein, and may be associated with different
actuators and/or controllers. Also, each sensor in an array may
operate independently or in association with (e.g., in parallel,
combination, or series) any number of other sensors in the
array.
[0914] A minicell of a biosensor of the invention may comprise a
detectable compound that produces a signal once ligands have bound
to the minicell. By way of non-limiting example, a minicell may
display a receptor for a ligand and contain a fluorescent compound.
The binding and internalization of the ligand into the minicell
results in FRET, shifting the wavelength of the signal. See, by way
of non-limiting example, Billinton et al., Development of a green
fluorescent protein reporter for a yeast genotoxicity biosensor,
Biosensors & Bioelectronics 13:831-838, 1998. A biosensor
according to the invention may use microbalance sensor systems
(Hengerer et al., Determination of phage antibody affinities to
antigen by a microbalance sensor system, BioTechniques 26:956-964,
1999).
[0915] XVIII.A.2. Surface Plasmon Resonance
[0916] Kd is measured using surface plasmon resonance on a chip,
for example, with a BIAcore.RTM. chip coated with immobilized
binding components, or similar systems such as the IAsys from
Thermo Labsystems, Affinity Sensors Division (Cambridge, U.K.) or
the BIOS-1 system from Artificial Sensing, Inc. (Zurich,
Switzerland). See Fitzgerald, Coupling optical biosensor technology
with micropreparative HPLC: Part 1, Am Biotech Lab November 2000,
p.10 and 12; Fitzgerald, Coupling optical biosensor technology with
micropreparative HPLC: Part 2, Am Biotech Lab February 2001, 14, 16
and 18; and Leatherbarrow et al., Analysis of molecular recognition
using optical sensors, Current Opinion in Chem Biol 3:544-547,
1999).
[0917] Surface plasmon resonance is used to characterize the
microscopic association and dissociation constants of reaction
between an antibody or antibody fragment and its ligand. Such
methods are generally described in the following references that
are incorporated herein by reference. (Vely F. et al., BIAcore
analysis to test phosphopeptide-SH2 domain interactions, Methods in
Molecular Biology. 121:313-21, 2000; Liparoto et al., Biosensor
analysis of the interleukin-2 receptor complex, Journal of
Molecular Recognition. 12:316-21, 1999; Lipschultz et al.,
Experimental design for analysis of complex kinetics using surface
plasmon resonance, Methods. 20):310-8, 2000; Malmqvist., BIACORE:
an affinity biosensor system for characterization of biomolecular
interactions, Biochemical Society Transactions 27:335-40, 1999;
Alfthan, Surface plasmon resonance biosensors as a tool in antibody
engineering, Biosensors & Bioelectronics. 13:653-63,
1998;,Fivash et al., BIAcore for macromolecular interaction,
Current Opinion in Biotechnology. 9:97-101, 1998; Price et al.;
Summary report on the ISOBM TD-4 Workshop: analysis of 56
monoclonal antibodies against the MUC 1 mucin. Tumour Biology 19
Suppl 1:1-20, 1998; Malmqvist et al, Biomolecular interaction
analysis: affinity biosensor technologies for functional analysis
of proteins, Current Opinion in Chemical Biology. 1:378-83, 1997;
O'Shannessy et al., Interpretation of deviations from
pseudo-first-order kinetic behavior in the characterization of
ligand binding by biosensor technology, Analytical Biochemistry.
236:275-83, 1996; Malmborg et al., BIAcore as a tool in antibody
engineering, Journal of Immunological Methods. 183:7-13, 1995; Van
Regenmortel, Use of biosensors to characterize recombinant
proteins, Developments in Biological Standardization. 83:143-51,
1994; O'Shannessy, Determination of kinetic rate and equilibrium
binding constants for macromolecular interactions: a critique of
the surface plasmon resonance literature, Current Opinions in
Biotechnology. 5:65-71, 1994).
[0918] BIAcore.RTM. uses the optical properties of surface plasmon
resonance (SPR) to detect alterations in protein concentration
bound within to a dextran matrix lying on the surface of a
gold/glass sensor chip interface, a dextran biosensor matrix. In
brief, proteins are covalently bound to the dextran matrix at a
known concentration and a ligand for the protein (e.g., antibody)
is injected through the dextran matrix. Near infra red light,
directed onto the opposite side of the sensor chip surface is
reflected and also induces an evanescent wave in the gold film,
which in turn, causes an intensity dip in the reflected light at a
particular angle known as the resonance angle. If the refractive
index of the sensor chip surface is altered (e.g., by ligand
binding to the bound protein) a shift occurs in the resonance
angle. This angle shift can be measured and is expressed as
resonance units (RUs) such that 1000 RUs is equivalent to a change
in surface protein concentration of 1 ng/mm2. These changes are
displayed with respect to time along the y-axis of a sensorgram,
which depicts the association and dissociation of any biological
reaction.
[0919] Additional details may be found in Jonsson et al.,
Introducing a biosensor based technology for real-time biospecific
interaction analysis, (1993) Ann. Biol. Clin. 51:19-26; Jonsson et
al., Real-time biospecific interaction analysis using surface
plasmon resonance and a sensor chip technology, (1991)
Biotechniques 11:620-627; Johnsson et al., Comparison of methods
for immobilization to carboxymethyl dextran sensor surfaces by
analysis of the specific activity of monoclonal antibodies, (1995)
J. Mol. Recognit. 8:125-131; and Johnsson, Immobilization of
proteins to a carboxymethyldextran-modified gold surface for
biospecific interaction analysis in surface plasmon resonance
sensors (1991) Anal. Biochem. 198:268-277, Karlsson et. al.,
Kinetic analysis of monoclonal antibody-antigen interactions with a
new biosensor based analytical system J. Immunol. Meth., 145, 229,
1991; Weinberger et al., Recent trends in protein biochip
technology, Pharmacogenomics 2000 November; 1(4):395-416;
Lipschultz et al., Experimental design for analysis of complex
kinetics using surface plasmon resonance, Methods 2000
March;20(3):310-8.
[0920] XVIII.B. Toxicological Sampling
[0921] Minicells are ideally suited for in vitro diagnostic
toxicological applications in which toxins, poisons, infectious
agents or pathogens, heavy metals, pollutants, caustic agents,
allergens, organic molecules, radionuclides, or other environmental
contaminants present either in air, water, soil samples and/or
fluid and/or tissue samples of organisms can be assessed. An
embodiment of this invention, minicells expressing proteins or
other molecules could be used in variety of diagnostic detection
platforms, including microwell formats, lateral flow devices,
molecular switches, biosensors, badges and other sensing devices.
Without being limited to the following examples, such devices could
be used for early warning of chemical and/or bioweapon attack,
illegal drug detection, explosives detection, biohazard detection,
pollution assessment, pesticide contamination, allergen detection
and detection of toxic or hazardous gasses. In a related
application, minicells could be used to eliminate, modify or
inactivate the agents.
[0922] In one non-limiting example of protein expression on
minicells for toxicological detection, olfactory receptors could be
expressed by minicells. The olfactory system possesses the ability
to recognize and differentiate between a wide range of odorants
based on odor molecules interacting with specific receptor proteins
in the ciliary membrane of olfactory neurons (Lancet, D., 1986.
Vertebrate olfactory reception. Ann. Rev. Neurosci. 9:329-355;
Shepherd, G. M., 1994. Discrimination of molecular signals by the
olfactory receptor neuron. Neuron 13:771-790). These receptors were
found to be 7-transmembrane-domain members of the G protein-coupled
receptor family (Buck, L. and R. Alex. 1991. A novel multigene
family may encode odorant receptors: A molecular basis for odor
recognition. Cell 65:175-187). Using a murine receptor library,
olfactory receptors were functionally expressed in HEK-293 cells
(Krautwurst, D., et al., 1998. Identification of ligands for
olfactory receptors by functional expression of a receptor library.
Cell. 95:917-926). By coexpressing the cloned receptors with G
15,16 subunits, the modified receptor system upon activation leads
to an increase in intracellular Ca.sup.2+. Calcium levels were
measured employing the dye FURA-2 and ratiofluormetric imaging.
This system demonstrated ligand specificity and structure-function
relationships for identified olfactory receptors. Employing similar
techniques, OR17-40, a human olfactory receptor protein, was
expressed in human embryonic kidney 293 cells and Xenopus Laevis
oocytes (Wetzel, H., et al. 1999. Specificity and sensitivity of a
human olfactory receptor functionally expressed in Human Embryonic
Kidney 293 Cells and Xenopus Laevis Oocytes. J. Neurosciences.
19:7426-7433). The receptor was functionally expressed in a manner
designed to assess the specificity of its binding to the ligand,
helional.
[0923] In one non-limiting example of target protein
identification, primers from homologous areas in transmembrane II
and transmembrane VII of olfactory GPCRs will be used to identify
unique receptor sequences. These sequences are inserted into
expression vectors. Minicell producing bacteria are transformed
with these vectors and cultured. Minicells are isolated from the
culture as previously described and subsequently induced. Using HTS
previously described, the functional receptor/minicells which
generate signal for binding of an odiferous toxin to the receptor
are identified. Large scaleLarge-scale production of the minicells
is carried out and the minicells are covalently coupled to the
surface of a microarraymicro array chip. The chip is supported in
an air sampler,, which feeds atmosphere over surface of the chip on
a continuous basis. If the toxic agent is present in the air, the
binding to the receptor activates a series of events ending in the
generation of a signal identifying the presence of the agent in the
air.
[0924] By way of non-limiting example, standard molecular
biological techniques can be used as follows: cDNA for GFP is
ligated to the 3' end of cDNA sequence for the receptor described
above. The resulting sequence is inserted into an expression
vector. Minicell producing bacteria are transformed with these
vectors and cultured. Minicells are isolated from the culture as
previously described and subsequently induced. The minicells now
contain the receptor to the ligand on the surface of the minicell
with a GFP tag on the C-terminus of the protein in the cytosol.
These minicells are packed into filters. Air is passed through the
filter. If the ligand is present, it will bind to the receptor. The
filter packing is suspended on applied to a diagnostic device.
Antibody to the ligand/receptor binding site complex is fixed on
the capture zone. When the sample is applied to the device, the
receptor/ligand complex is captured. The capture zone is screened
for signal resulting from the presence of GFP. This can be
extrapolated to have multiple unique receptor/minicell moieties in
the same sampling device. Each receptor would have a unique
fluorescing protein tag such that different emissions identify
specific agents in the air.
[0925] Other methods for quantification associated take advantage
of the composition of the minicell. Loading of the minicell by
transiently permeabilizing the membrane to allow for migration of
molecules into to the cytosol. These molecules include but are not
limited to radiolabeled molecules ( i.e., nucleotides), stains or
dyes (DAPI or other DNA staining, heavy metals, fluorophores. The
molecules could also be synthesized within the minicell (i.e. GFP).
The association of a specific ligand with the minicell could cause
a redox shift that induce a color change in the solution or could
shift the energy potential in the reaction are generating an
electrical current. Each of this examples are associated with well
know methods for measuring each of the resulting changes. These
include but are not limited to radioactivity or fluorescence
generated or the color shift by spectrophotometry.
[0926] A multigene family of gustatory G protein-coupled receptors
expressed in the lingual epithelia has been identified with
structural similarities to olfactory receptors (Abe, K., et al.
1993. Multiple genes for G protein-coupled receptors and their
expression in lingual epithelia. FEBS. 316:253-256; Abe, K., et al.
1993. Primary structure and cell-type specific expression of a
gustatory G protein-coupled receptor related to olfactory
receptors. J. Bio. Chem.). This provides an addition example of
receptors which can be isolated, expressed in minicells and then be
used for identification of specific substances in various matrices
in similar manners as identified for olfactory receptor
minicells.
[0927] As a non-limiting example of minicell use in
toxicological/environmental detection, arrays could be constructed
in which each well contains a distinct minicell subtype displaying
membrane-bound proteins or other molecules for each of several
potential toxins or agents in the environment. For example,
minicells in such a format could be used to determine which agents
are present in the environment as a consequence of a chemical
and/or biological weapons attack. Non-limiting examples of
biosensors that have been used toxicological/environmental
detection include those described by Sticher et al., Development
and characterization of a whole-cell bioluminescent sensor for
bioavailable middle-chain alkanes in contaminated groundwater
samples, Appl. Envir. Microbiol. 63:4053-4060, 1997; Willardson et
al., Development and Testing of a Bacterial Biosensor for
Toluene-Based Environmental Contaminants, Appl. Envir. Microbiol.
64:1006-1012, 1998; Lars et al., Detection of Oxytetracycline
Production by Streptomyces rimosus in Soil Microcosms by Combining
Whole-Cell Biosensors and Flow Cytometry, Appl. Envir. Microbiol.
67:239-244, 2001; H.o slashed.jberg et al., Oxygen-Sensing Reporter
Strain of Pseudomonas fluorescens for Monitoring the Distribution
of Low-Oxygen Habitats in Soil, Appl. Envir. Microbiol. 1999 65:
4085-4093, 1999; R. P. Hollis et al., Design and Application of a
Biosensor for Monitoring Toxicity of Compounds to Eukaryotes, Appl.
Envir. Microbiol. 66: 1676-1679, 2000; Heitzer et al., Optical
biosensor for environmental on-line monitoring of naphthalene and
salicylate bioavailability with an immobilized bioluminescent
catabolic reporter bacterium, Appl. Envir. Microbiol. 60:1487-1494,
1994; Selifonova et al., Bioluminescent sensors for detection of
bioavailable Hg(II) in the environment, Appl. Envir. Microbiol. 59:
3083-3090, 1993; Jaeger et al., Mapping of Sugar and Amino Acid
Availability in Soil around Roots with Bacterial Sensors of Sucrose
and Tryptophan, Appl. Envir. Microbiol. 65: 2685-2690, 1999; and
Larsen et al., A Microsensor for Nitrate Based on Immobilized
Denitrifying Bacteria, Appl. Envir. Microbiol. 62: 1248-1251,
1996.
[0928] XVIII.C. Toxin Elimination
[0929] In another embodiment of the invention, minicells displaying
a receptor for a particular toxic agent could be used for the
elimination of the agent from the environment. In a non-limiting
example of this technology, minicells could be placed in a
filtering apparatus to eliminate the toxic agent from the
environment (e.g., air, water soil). In the example of atmospheric
contamination, the air would be circulated through a forced air
system containing in-line filters composed of a housing, support
matrix and receptor/minicells. As air passes over the minicells,
the toxin is bound to the receptor. The purified air passed out of
the system and into the atmosphere. A similar method for water
purification would follow a similar protocol replacing the receptor
for the toxin with the receptor or other protein binding a unique
epitope on contaminant wishing to be removed. Examples include but
are not limited to removing toxins, parasites or microbes from the
matrix such as water or air. This represent non-limiting example of
minicell-based technology for expression of functional receptors or
binding moieties of receptors on the minicell's surface for the
specific purpose of selectively capturing, identifying, quantifying
and/or removing molecules of interest for environmental
compartments to include but not limited to air water, soil, other
gas phases or liquid solutions.
[0930] Representative toxins include, but are not limited to, those
associated with "red tides"; eubacterial toxins, such as those
toxins produced by Corynebacterium diphtheriae (diphtheria),
Bordetella pertussis (whooping cough), Vibrio cholerae (cholera),
Bacillus anthracis (anthrax), Clostridium botulinum (botulism),
Clostridium tetani (tetanus), and enterohemorrhagic Escherichia
coli (bloody diarrhea and hemolytic uremic syndrome); and fungal
toxins (e.g., aflatoxin, gliotoxin, cyclopeptides, orellanine,
gyrometrin, coprine, muscarine, ibotenic acid, psilocybin, psilocin
and baeocystin).
[0931] The treatment of "red tides" with minicells exemplifies this
aspect of the invention. A red tide occurs as a result of a
higher-than-normal concentration of an algae or dinoflagellate
which, when present in dense concentrations as a result of a
"bloom," form colored patches on the surface of water. The colored
patches are pink, violet, orange, yellow, blue, green, brown, or
red, with red being the most common color. The organisms that cause
red tides often produce toxins that have negative impacts on other
organisms, including humans.
[0932] For example, Karenia brevis (formerly Gymnodinium breve)
produces a toxin (domoic acid) that affects the central nervous
system of fish, shellfish and other organisms, resulting in a state
of paralysis. Alexandrium species (e.g., A. tamarense, A.
fundyense), Dinophysis and Gonyaulax species; and Pseudo-nitzschia
multiseries, which cause, respectively, paralytic, diarrhetic and
amnesic shellfish poisoning. Because shellfish containing the toxin
taste and appear the same as shellfish that do not, and cooking
does not destroy the toxin, human ingestion of the former can cause
disease in humans and other organisms. For example, one form of
paralytic shellfish poisoning, which can be fatal to humans,
results from saxitoxin, which is produced by Gonyaulax tamarenis,
Protogonyaulax catanella, and other species. Other algae that can
result in red tides include Gonyaulax catenella, and Ptychdiscus
breve.
[0933] Minicells that comprise a binding moiety of an organism that
produces a red tide, or of the toxin produced thereby, can be used
for remediation. For example, a minicell having a binding moiety
directed to a red tide-producing organism can be used to deliver an
antibiotic thereto, and a minicell with a binding moiety directed
to a toxin can be used to bind and/or internalize the toxin. As is
explained in more detail elsewhere herein, a minicell with a
binding moiety directed to a toxin can also be used for therapeutic
purposes.
[0934] XVIII.D. Bioremediation
[0935] In another non-limiting example of the potential use of
minicells in a toxicological context is their use in
bioremediation, the process by which living organisms act to
degrade or transform hazardous organic contaminants. As used
herein, "bioremediation" is the process of using biological or
biologically derived compositions that alter the chemical structure
and/or bind, an undesirable substance in order to reduce the
effective concentration of the undesirable substance, thereby
reducing or eliminating the effect(s) of the undesirable compound
on the environment. Undesirable substances include, but are not
limited to, pollutants (e.g., heavy metals, pesticides, herbicides,
petroleum products); biological toxins (e.g., such as those
produced by "red tides", e.g., domoic acid, saxitoxin); pathogens
(e.g., viruses, eubacteria); organisms that produce toxins;
biological waste products (e.g., sewage, guano), and undesirable
organisms therewithin (e.g., pathogenic eubacteria).
[0936] The term "bioremediation" encompasses both biodegradation,
the breakdown of organic substances by microorganisms, and
biotransformation, the alteration of the structure of a compound by
a living organism or enzyme. The minicells of the invention may be
incorporated into biofilters, i.e., devices in which gases,
liquids, powders and the like are passed through media containing
biodegrading minicells, including but not limited to devices that
biodegrade volatile organic compounds in air by passing the air
therethrough.
[0937] Bioremedation can be used to process undesirable substances
in a composition prior to or after the release of the composition
into the environment. For example, bioremediation can be applied in
sewage treatment plants to process sewage prior to its release, or
to sewage that has been accidentally or otherwise released into the
environment.
[0938] Environmental microbiologists have sought to identify and
use specific bacteria that degrade pollutants and other
environmental containments. See, for example, Chakrabarty,
Microbial Degradation of Toxic Chemicals: Evolutionary Insights and
Practical Considerations, Am. Soc. Micro. Biol. News 62:130-137,
1996; and U.S. Pat. Nos. 4,511,657; 4,493,895; 4,871,673; and
4,535,061. In instances where a live organism is placed into the
environment to process undesirable substances, there is a concern
that the organism might have undesirable effects that would be made
more deleterious due to the ability of the live organism to
replicate (Sayler G S, Ripp S. Field applications of genetically
engineered microorganisms for bioremediation processes. Curr Opin
Biotechnol. 2000 June 11(3):286-9; and Diaz E, Ferrandez A, Prieto
M A, Garcia J L. Biodegradation of aromatic compounds by
Escherichia coli. Microbiol Mol Biol Rev. 2001
December;65(4):523-69). For example, when it has been proposed to
use genetically altered eubacteria to process oil spills, the
concern has been raised that the eubacteria might spread beyond the
oil spill and into supplies of petroleum products that are used to
produce energy, where they would process and render useless the
stored petroleum products. However, because they lack the ability
to replicate, such a scenario will not occur when minicells are use
for bioremediation.
[0939] By way of non-limiting example, octane enhances such as
methyl t-butyl ether or aromatic hydrocarbons contaminate the
aquifer and soil. These agents negatively impact the many microbes
in the effected area thus limiting capability of the microbial
community rectify the environmental insult. Bioaugmentation, the
addition to the environment of microorganisms that can metabolize
and grow on specific organic compounds, to facilitate degradation
may prove useful, but concerns exist relative to the regulation of
newly introduced bacteria. The minicell provides a vehicle to
accomplish biodegradation without bacterial overgrowth.
[0940] Diphenyl ethers and cyclic ethers such as dioxane and furan
have shown to be metabolized by soil bacteria. Using classic
isolation and screening techniques identified above, genes encoding
for the oxygenases or hydroylases are isolated. The enzyme sequence
is inserted into an expression vector using standard molecular
biology techniques. Minicell producing bacteria are transformed
with these vectors and cultured. Minicells are isolated from the
culture as previously described and subsequently induced. The
minicells are applied to the area contaminated with aromatic
hydrocarbons. These compounds are transported either actively or
passively in to the minicell and subsequently degraded by the
oxygenase or hydroylase. One advantage of this focused degradation
is the minimizing of feedback inhibition because the only machinery
of consequence in the minicell is that related to the degradation
of the ether compounds.
[0941] Similarly, beginning with genetic material from Dehalobacter
enzymes responsible for the biodegrading of tetrachloroethane could
be isolated as described above. The sequence for the enzyme is
inserted into the expression vector and used to transform
minicell-producing bacteria. The bacteria are cultured, minicells
isolated from the culture and the minicells induced as previously
described. Minicell preps are lyophilized using standard
lyophilization techniques. The resulting material is transported to
the site of tetrachloroethene contamination and reconstituted and
applied. As the tetracholoethene was assimilated, it is be degraded
by the enzyme system.
[0942] These are non-limiting examples scope of
bioremediation/biotranform- ation using minicell technology. The
scope of the invention includes taking advantage of metabolic
pathways organism in general to include but not limited to
eukaryotes, prokaryotes, fungi, animals or plants.
[0943] XVIII. E. Fermentation
[0944] Delivery of specific enzymes in an untargeted fashion by the
minicell allows for packaged delivery without the increased biomass
and complex metabolic products associated with processes using live
organisms. This aspect can be taken advantage of in fermentation,
where the addition of minicells into which unique enzymes have been
added are used to modulate the composition of the environment to
include but not limited to the alcohol, sugar and acid levels.
[0945] XVIII. F. Pesticides
[0946] Bacillus thurigenesis produces a toxin that kills plant
chewing insect larvae as well as mosquito larvae. The toxin,
Cry1Ac, binds to aminopeptidase N receptor on the endothelium of
the midgut. Minicell technology is allows for delivery of the
toxin. The toxin sequence is modified by ligation of a sequence
coding for a transmembrane domain as previously described. The
sequence for this fusion protein inserted into an expression vector
using standard molecular biology techniques. To facilitate the
consumption of the toxin/minicell plasmids containing sequences
incorporating the sequence for pheromones coupled at the C-terminus
to the sequence for a transmembrane domain is generated using
standard molecular biological techniques. This fusion protein
sequence is inserted into the expression containing coding region
for the toxin fusion protein or inserted into a unique expression
vector. Minicell producing bacteria are transformed with these
vectors and cultured. Minicells are isolated from the culture as
previously described and subsequently induced. The minicells are
distributed (e.g. crop dusting) to the area of infestation. The
toxin/minicells are ingested by the larvae and kill the larvae as
the minicells passes through the gut.
XIX. Pharmaceutical Compositions
[0947] Another aspect of the invention is drawn to compositions,
including but not limited to pharmaceutical compositions. According
to the invention, a "composition" refers to a mixture comprising at
least one carrier, preferably a physiologically acceptable carrier,
and one or more minicell compositions. The term "carrier" defines a
chemical compound that does not inhibit or prevent the
incorporation of the biologically active peptide(s) into cells or
tissues. A carrier typically is an inert substance that allows an
active ingredient to be formulated or compounded into a suitable
dosage form (e.g., a pill, a capsule, a gel, a film, a tablet, a
microparticle (e.g., a microsphere), a solution; an ointment; a
paste, an aerosol, a droplet, a colloid or an emulsion etc.). A
"physiologically acceptable carrier" is a carrier suitable for use
under physiological conditions that does not abrogate (reduce,
inhibit, or prevent) the biological activity and properties of the
compound. For example, dimethyl sulfoxide (DMSO) is a carrier as it
facilitates the uptake of many organic compounds into the cells or
tissues of an organism. Preferably, the carrier is a
physiologically acceptable carrier, preferably a pharmaceutically
or veterinarily acceptable carrier, in which the minicell
composition is disposed.
[0948] A "pharmaceutical composition" refers to a composition
wherein the carrier is a pharmaceutically acceptable carrier, while
a "veterinary composition" is one wherein the carrier is a
veterinarily acceptable carrier. The term "pharmaceutically
acceptable carrier" or "veterinarily acceptable carrier" includes
any medium or material that is not biologically or otherwise
undesirable, i.e., the carrier may be administered to an organism
along with a minicell composition without causing any undesirable
biological effects or interacting in a deleterious manner with the
complex or any of its components or the organism. Examples of
pharmaceutically acceptable reagents are provided in The United
States Pharmacopeia, The National Formulary, United States
Pharmacopeial Convention, Inc., Rockville, Md. 1990, hereby
incorporated by reference herein into the present application. The
terms "therapeutically effective amount" or "pharmaceutically
effective amount" mean an amount sufficient to induce or effectuate
a measurable response in the target cell, tissue, or body of an
organism. What constitutes a therapeutically effective amount will
depend on a variety of factors, which the knowledgeable
practitioner will take into account in arriving at the desired
dosage regimen.
[0949] The compositions of the invention can further comprise other
chemical components, such as diluents and excipients. A "diluent"
is a chemical compound diluted in a solvent, preferably an aqueous
solvent, that facilitates dissolution of the composition in the
solvent, and it may also serve to stabilize the biologically active
form of the composition or one or more of its components. Salts
dissolved in buffered solutions are utilized as diluents in the
art. For example, preferred diluents are buffered solutions
containing one or more different salts. A preferred buffered
solution is phosphate buffered saline (particularly in conjunction
with compositions intended for pharmaceutical administration), as
it mimics the salt conditions of human blood. Since buffer salts
can control the pH of a solution at low concentrations, a buffered
diluent rarely modifies the biological activity of a biologically
active peptide.
[0950] An "excipient" is any more or less inert substance that can
be added to a composition in order to confer a suitable property,
for example, a suitable consistency or to form a drug. Suitable
excipients and carriers include, in particular, fillers such as
sugars, including lactose, sucrose, mannitol, or sorbitol cellulose
preparations such as, for example, maize starch, wheat starch, rice
starch, agar, pectin, xanthan gum, guar gum, locust bean gum,
hyaluronic acid, casein potato starch, gelatin, gum tragacanth,
methyl cellulose, hydroxypropylmethyl-cellulose, polyacrylate,
sodium carboxymethylcellulose, and/or polyvinylpyrrolidone (PVP).
If desired, disintegrating agents can also be included, such as
cross-linked polyvinyl pyrrolidone, agar, or alginic acid or a salt
thereof such as sodium alginate. Other suitable excipients and
carriers include hydrogels, gellable hydrocolloids, and chitosan.
Chitosan microspheres and microcapsules can be used as carriers.
See WO 98/52547 (which describes microsphere formulations for
targeting compounds to the stomach, the formulations comprising an
inner core (optionally including a gelled hydrocolloid) containing
one or more active ingredients, a membrane comprised of a water
insoluble polymer (e.g., ethylcellulose) to control the release
rate of the active ingredient(s), and an outer layer comprised of a
bioadhesive cationic polymer, for example, a cationic
polysaccharide, a cationic protein, and/or a synthetic cationic
polymer; U.S. Pat. No. 4,895,724. Typically, chitosan is
cross-linked using a suitable agent, for example, glutaraldehyde,
glyoxal, epichlorohydrin, and succinaldehyde. Compositions
employing chitosan as a carrier can be formulated into a variety of
dosage forms, including pills, tablets, microparticles, and
microspheres, including those providing for controlled release of
the active ingredient(s). Other suitable bioadhesive cationic
polymers include acidic gelatin, polygalactosamine, polyamino acids
such as polylysine, polyhistidine, polyornithine, polyquaternary
compounds, prolamine, polyimine, diethylaminoethyldextran (DEAE),
DEAE-imine, DEAE-methacrylate, DEAE-acrylamide, DEAE-dextran,
DEAE-cellulose, poly-p-aminostyrene, polyoxethane,
copolymethacrylates, polyamidoamines, cationic starches,
polyvinylpyridine, and polythiodiethylaminomethylethylene.
[0951] The compositions of the invention can be formulated in any
suitable manner. Minicell compositions may be uniformly
(homogeneously) or non-uniformly (heterogenously) dispersed in the
carrier. Suitable formulations include dry and liquid formulations.
Dry formulations include freeze dried and lyophilized powders,
which are particularly well suited for aerosol delivery to the
sinuses or lung, or for long term storage followed by
reconstitution in a suitable diluent prior to administration. Other
preferred-dry formulations include those wherein a composition
according to the invention is compressed into tablet or pill form
suitable for oral administration or compounded into a sustained
release formulation. When the composition is intended for oral
administration but is to be delivered to epithelium in the
intestines, it is preferred that the formulation be encapsulated
with an enteric coating to protect the formulation and prevent
premature release of the minicell compositions included therein. As
those in the art will appreciate, the compositions of the invention
can be placed into any suitable dosage form. Pills and tablets
represent some of such dosage forms. The compositions can also be
encapsulated into any suitable capsule or other coating material,
for example, by compression, dipping, pan coating, spray drying,
etc. Suitable capsules include those made from gelatin and starch.
In turn, such capsules can be coated with one or more additional
materials, for example, and enteric coating, if desired. Liquid
formulations include aqueous formulations, gels, and emulsions.
[0952] Some preferred embodiments concern compositions that
comprise a bioadhesive, preferably a mucoadhesive, coating. A
"bioadhesive coating" is a coating that allows a substance (e.g., a
minicellcomposition) to adhere to a biological surface or substance
better than occurs absent the coating. A "mucoadhesive coating" is
a preferred bioadhesive coating that allows a substance, for
example, a composition according to the invention, to adhere better
to mucosa occurs absent the coating. For example, micronized
particles (e.g., particles having a mean diameter of about 5, 10,
25, 50, or 100 .mu.m) can be coated with a mucoadhesive. The coated
particles can then be assembled into a dosage form suitable for
delivery to an organism. Preferably, and depending upon the
location where the cell surface transport moiety to be targeted is
expressed, the dosage form is then coated with another coating to
protect the formulation until it reaches the desired location,
where the mucoadhesive enables the formulation to be retained while
the composition interacts with the target cell surface transport
moiety.
[0953] The compositions of the invention may be administered to any
organism, preferably an animal, preferably a mammal, bird, fish,
insect, or arachnid. Preferred mammals include bovine, canine,
equine, feline, ovine, and porcine animals, and non-human primates.
Humans are particularly preferred. Multiple techniques of
administering or delivering a compound exist in the art including,
but not limited to, oral, rectal (e.g. an enema or suppository)
aerosol (e.g., for nasal or pulmonary delivery), parenteral, and
topical administration. Preferably, sufficient quantities of the
biologically active peptide are delivered to achieve the intended
effect. The particular amount of composition to be delivered will
depend on many factors, including the effect to be achieved, the
type of organism to which the composition is delivered, delivery
route, dosage regimen, and the age, health, and sex of the
organism. As such, the particular dosage of a composition
incorporated into a given formulation is left to the ordinarily
skilled artisan's discretion.
[0954] Those skilled in the art will appreciate that when the
compositions of the present invention are administered as agents to
achieve a particular desired biological result, which may include a
therapeutic or protective effect(s) (including vaccination), it may
be necessary to combine the fusion proteins of the invention with a
suitable pharmaceutical carrier. The choice of pharmaceutical
carrier and the preparation of the fusion protein as a therapeutic
or protective agent will depend on the intended use and mode of
administration. Suitable formulations and methods of administration
of therapeutic agents include those for oral, pulmonary, nasal,
buccal, ocular, dermal, rectal, or vaginal delivery.
[0955] Depending on the mode of delivery employed, the
context-dependent functional entity can be delivered in a variety
of pharmaceutically acceptable forms. For example, the
context-dependent functional entity can be delivered in the form of
a solid, solution, emulsion, dispersion, micelle, liposome, and the
like, incorporated into a pill, capsule, tablet, suppository,
areosol, droplet, or spray. Pills, tablets, suppositories,
areosols, powders, droplets, and sprays may have complex,
multilayer structures and have a large range of sizes. Aerosols,
powders, droplets, and sprays may range from small (1 micron) to
large (200 micron) in size.
[0956] Pharmaceutical compositions of the present invention can be
used in the form of a solid, a lyophilized powder, a solution, an
emulsion, a dispersion, a micelle, a liposome, and the like,
wherein the resulting composition contains one or more of the
compounds of the present invention, as an active ingredient, in
admixture with an organic or inorganic carrier or excipient
suitable for enteral or parenteral applications. The active
ingredient may be compounded, for example, with the usual
non-toxic, pharmaceutically acceptable carriers for tablets,
pellets, capsules, suppositories, solutions, emulsions,
suspensions, and any other form suitable for use. The carriers
which can be used include glucose, lactose, mannose, gum acacia,
gelatin, mannitol, starch paste, magnesium trisilicate, talc, corn
starch, keratin, colloidal silica, potato starch, urea, medium
chain length triglycerides, dextrans,and other carriers suitable
for use in manufacturing preparations, in solid, semisolid, or
liquid form. In addition auxiliary, stabilizing, thickening and
coloring agents and perfumes may be used. Examples of a stabilizing
dry agent includes triulose, preferably at concentrations of 0.1%
or greater (See, e.g., U.S. Pat. No. 5,314,695). The active
compound is included in the pharmaceutical composition in an amount
sufficient to produce the desired effect upon the process or
condition of diseases.
XX. Small Molecules
[0957] The term "small molecule" includes any chemical or other
moiety that can act to affect biological processes. Small molecules
can include any number of therapeutic agents presently known and
used, or can be small molecules synthesized in a library of such
molecules for the purpose of screening for biological function(s).
Small molecules are distinguished from macromolecules by size. The
small molecules of this invention usually have molecular weight
less than about 5,000 daltons (Da), preferably less than about
2,500 Da, more preferably less than 1,000 Da, most preferably less
than about 500 Da.
[0958] Small molecules include without limitation organic
compounds, peptidomimetics and conjugates thereof. As used herein,
the term "organic compound" refers to any carbon-based compound
other than macromolecules such nucleic acids and polypeptides. In
addition to carbon, organic compounds may contain calcium,
chlorine, fluorine, copper, hydrogen, iron, potassium, nitrogen,
oxygen, sulfur and other elements. An organic compound may be in an
aromatic or aliphatic form. Non-limiting examples of organic
compounds include acetones, alcohols, anilines, carbohydrates,
monosaccharides, oligosaccharides, polysaccharides, amino acids,
nucleosides, nucleotides, lipids, retinoids, steroids,
proteoglycans, ketones, aldehydes, saturated, unsaturated and
polyunsaturated fats, oils and waxes, alkenes, esters, ethers,
thiols, sulfides, cyclic compounds, heterocylcic compounds,
imidizoles and phenols. An organic compound as used herein also
includes nitrated organic compounds and halogenated (e.g.,
chlorinated) organic compounds: Methods for preparing
peptidomimetics are described below. Collections of small
molecules, and small molecules identified according to the
invention are characterized by techniques such as accelerator mass
spectrometry (AMS; see Turteltaub et al., Curr Pharm Des 2000
6(10):991-1007, Bioanalytical applications of accelerator mass
spectrometry for pharmaceutical research; and Enjalbal et al., Mass
Spectrom Rev 2000 19(3):139-61, Mass spectrometry in combinatorial
chemistry.)
[0959] Preferred small molecules are relatively easier and less
expensively manufactured, formulated or otherwise prepared.
Preferred small molecules are stable under a variety of storage
conditions. Preferred small molecules may be placed in tight
association with macromolecules to form molecules that are
biologically active and that have improved pharmaceutical
properties. Improved pharmaceutical properties include changes in
circulation time, distribution, metabolism, modification,
excretion, secretion, elimination, and stability that are favorable
to the desired biological activity. Improved pharmaceutical
properties include changes in the toxicological and efficacy
characteristics of the chemical entity.
XXI. Polypeptides AND Derivatives
[0960] XXI.A. Polypeptides
[0961] As used herein, the term "polypeptide" includes proteins,
fusion proteins, oligopeptides and polypeptide derivatives, with
the exception that peptidomimetics are considered to be small
molecules herein. Although they are polypeptides, antibodies and
their derivatives are described in a separate section. Antibodies
and antibody derivatives are described in a separate section, but
antibodies and antibody derivatives are, for purposes of the
invention, treated as a subclass of the polypeptides and
derivatives.
[0962] A "protein" is a molecule having a sequence of amino acids
that are linked to each other in a linear molecule by peptide
bonds. The term protein refers to a polypeptide that is isolated
from a natural source, or produced from an isolated cDNA using
recombinant DNA technology; and has a sequence of amino acids
having a length of at least about 200 amino acids.
[0963] A "fusion protein" is a type of recombinant protein that has
an amino acid sequence that results from the linkage of the amino
acid sequences of two or more normally separate polypeptides.
[0964] A "protein fragment" is a proteolytic fragment of a larger
polypeptide, which may be a protein or a fusion protein. A
proteolytic fragment may be prepared by in vivo or in vitro
proteolytic cleavage of a larger polypeptide, and is generally too
large to be prepared by chemical synthesis. Proteolytic fragments
have amino acid sequences having a length from about 200 to about
1,000 amino acids.
[0965] An "oligopeptide" is a polypeptide having a short amino acid
sequence (i.e., 2 to about 200 amino acids). An oligopeptide is
generally prepared by chemical synthesis.
[0966] Although oligopeptides and protein fragments may be
otherwise prepared, it is possible to use recombinant DNA
technology and/or in vitro biochemical manipulations. For example,
a nucleic acid encoding an amino acid sequence may be prepared and
used as a template for in vitro transcription/translation
reactions. In such reactions, an exogenous nucleic acid encoding a
preselected polypeptide is introduced into a mixture that is
essentially depleted of exogenous nucleic acids that contains all
of the cellular components required for transcription and
translation. One or more radiolabeled amino acids are added before
or with the exogenous DNA, and transcription and translation are
allowed to proceed. Because the only nucleic acid present in the
reaction mix is the exogenous nucleic acid added to the reaction,
only polypeptides encoded thereby are produced, and incorporate the
radiolabelled amino acid(s). In this manner, polypeptides encoded
by a preselected exogenous nucleic acid are radiolabeled. Although
other proteins are present in the reaction mix, the preselected
polypeptide is the only one that is produced in the presence of the
radiolabeled amino acids and is thus uniquely labeled.
[0967] As is explained in detail below, "polypeptide derivatives"
include without limitation mutant polypeptides, chemically modified
polypeptides, and peptidomimetics.
[0968] The polypeptides of this invention, including the analogs
and other modified variants, may generally be prepared following
known techniques. Preferably, synthetic production of the
polypeptide of the invention may be according to the solid phase
synthetic method. For example, the solid phase synthesis is well
understood and is a common method for preparation of polypeptides,
as are a variety of modifications of that technique [Merrifield
(1964), J. Am. Chem. Soc., 85: 2149; Stewart and Young (1984),
Solid Phase polypeptide Synthesis, Pierce Chemical Company,
Rockford, Ill.; Bodansky and Bodanszky (1984), The Practice of
polypeptide Synthesis, Springer-Verlag, New York; Atherton and
Sheppard (1989), Solid Phase polypeptide Synthesis: A Practical
Approach, IRL Press, New York]. See, also, the specific method
described in Example 1 below.
[0969] Alternatively, polypeptides of this invention may be
prepared in recombinant systems using polynucleotide sequences
encoding the polypeptides. For example, fusion proteins are
typically prepared using recombinant DNA technology.
[0970] XXI.B. Polypeptide Derivatives A "derivative" of a
polypeptide is a compound that is not, by definition, a
polypeptide, i.e., it contains at least one chemical linkage that
is not a peptide bond. Thus, polypeptide derivatives include
without limitation proteins that naturally undergo
post-translational modifications such as, e.g., glycosylation. It
is understood that a polypeptide of the invention may contain more
than one of the following modifications within the same
polypeptide. Preferred polypeptide derivatives retain a desirable
attribute, which may be biological activity; more preferably, a
polypeptide derivative is enhanced with regard to one or more
desirable attributes, or has one or more desirable attributes not
found in the parent polypeptide. Although they are described in
this section, peptidomimetics are taken as small molecules in the
present disclosure.
[0971] XXI.C. Mutant Polypeptide Derivatives
[0972] A polypeptide having an amino acid sequence identical to
that found in a protein prepared from a natural source is a
"wildtype" polypeptide. Mutant oligopeptides can be prepared by
chemical synthesis, including without limitation combinatorial
synthesis.
[0973] Mutant polypeptides larger than oligopeptides can be
prepared using recombinant DNA technology by altering the
nucleotide sequence of a nucleic acid encoding a polypeptide.
Although some alterations in the nucleotide sequence will not alter
the amino acid sequence of the polypeptide encoded thereby
("silent" mutations), many will result in a polypeptide having an
altered amino acid sequence that is altered relative to the parent
sequence. Such altered amino acid sequences may comprise
substitutions, deletions and additions of amino acids, with the
proviso that such amino acids are naturally occurring amino
acids.
[0974] Thus, subjecting a nucleic acid that encodes a polypeptide
to mutagenesis is one technique that can be used to prepare mutant
polypeptides, particularly ones having substitutions of amino acids
but no deletions or insertions thereof. A variety of mutagenic
techniques are known that can be used in vitro or in vivo including
without limitation chemical mutagenesis and PCR-mediated
mutagenesis. Such mutagenesis may be randomly targeted (i.e.,
mutations may occur anywhere within the nucleic acid) or directed
to a section of the nucleic acid that encodes a stretch of amino
acids of particular interest. Using such techniques, it is possible
to prepare randomized, combinatorial or focused compound libraries,
pools and mixtures.
[0975] Polypeptides having deletions or insertions of naturally
occurring amino acids may be synthetic oligopeptides that result
from the chemical synthesis of amino acid sequences that are based
on the amino acid sequence of a parent polypeptide but which have
one or more amino acids inserted or deleted relative to the
sequence of the parent polypeptide. Insertions and deletions of
amino acid residues in polypeptides having longer amino acid
sequences may be prepared by directed mutagenesis.
[0976] XXI.D. Chemically Modified Polypeptides
[0977] As contemplated by this invention, the term "polypeptide"
includes those having one or more chemical modification relative to
another polypeptide, i.e., chemically modified polypeptides. The
polypeptide from which a chemically modified polypeptide is derived
may be a wildtype protein, a mutant protein or a mutant
polypeptide, or polypeptide fragments thereof; an antibody or other
polypeptide ligand according to the invention including without
limitation single-chain antibodies, bacterial proteins and
polypeptide derivatives thereof; or polypeptide ligands prepared
according to the disclosure. Preferably, the chemical
modification(s) confer(s) or improve(s) desirable attributes of the
polypeptide but does not substantially alter or compromise the
biological activity thereof. Desirable attributes include but are
limited to increased shelf-life; enhanced serum or other in vivo
stability; resistance to proteases; and the like. Such
modifications include by way of non-limiting example N-terminal
acetylation, glycosylation, and biotinylation.
[0978] XXI.D.1. Polypeptides with N-Terminal or C-Terminal Chemical
Groups
[0979] An effective approach to confer resistance to peptidases
acting on the N-terminal or C-terminal residues of a polypeptide is
to add chemical groups at the polypeptide termini, such that the
modified polypeptide is no longer a substrate for the peptidase.
One such chemical modification is glycosylation of the polypeptides
at either or both termini. Certain chemical modifications, in
particular N-terminal glycosylation, have been shown to increase
the stability of polypeptides in human serum (Powell et al. (1993),
Pharma. Res. 10: 1268-1273). Other chemical modifications which
enhance serum stability include, but are not limited to, the
addition of an N-terminal alkyl group, consisting of a lower alkyl
of from 1 to 20 carbons, such as an acetyl group, and/or the
addition of a C-terminal amide or substituted amide group.
[0980] XXI.D.2. Polypeptides with a Terminal D-Amino Acid
[0981] The presence of an N-terminal D-amino acid increases the
serum stability of a polypeptide that otherwise contains L-amino
acids, because exopeptidases acting on the N-terminal residue
cannot utilize a D-amino acid as a substrate. Similarly, the
presence of a C-terminal D-amino acid also stabilizes a
polypeptide, because serum exopeptidases acting on the C-terminal
residue cannot utilize a D-amino acid as a substrate. With the
exception of these terminal modifications, the amino acid sequences
of polypeptides with N-terminal and/or C-terminal D-amino acids are
usually identical to the sequences of the parent L-amino acid
polypeptide.
[0982] XXI.D.3. Polypeptides With Substitution of Natural Amino
Acids By Unnatural Amino Acids
[0983] Substitution of unnatural amino acids for natural amino
acids in a subsequence of a polypeptide can confer or enhance
desirable attributes including biological activity. Such a
substitution can, for example, confer resistance to proteolysis by
exopeptidases acting on the N-terminus. The synthesis of
polypeptides with unnatural amino acids is routine and known in the
art (see, for example, Coller, et al. (1993), cited above).
[0984] XXI.D.4. Post-Translational Chemical Modifications
[0985] Different host cells will contain different
post-translational modification mechanisms that may provide
particular types of post-translational modification of a fusion
protein if the amino acid sequences required for such modifications
is present in the fusion protein. A large number (.about.100) of
post-translational modifications have been described, a few of
which are discussed herein. One skilled in the art will be able to
choose appropriate host cells, and design chimeric genes that
encode protein members comprising the amino acid sequence needed
for a particular type of modification.
[0986] Glycosylation is one type of post-translational chemical
modification that occurs in many eukaryotic systems, and may
influence the activity, stability, pharmacogenetics, immunogenicity
and/or antigenicity of proteins. However, specific amino acids must
be present at such sites to recruit the appropriate glycosylation
machinery, and not all host cells have the appropriate molecular
machinery. Saccharomyces cerevisieae and Pichia pastoris provide
for the production of glycosylated proteins, as do expression
systems that utilize insect cells, although the pattern of
glyscoylation may vary depending on which host cells are used to
produce the fusion protein.
[0987] Another type of post-translation modification is the
phosphorylation of a free hydroxyl group of the side chain of one
or more Ser, Thr or Tyr residues. Protein kinases catalyze such
reactions. Phosphorylation is often reversible due to the action of
a protein phosphatase, an enzyme that catalyzes the
dephosphorylation of amino acid residues.
[0988] Differences in the chemical structure of amino terminal
residues result from different host cells, each of which may have a
different chemical version of the methionine residue encoded by a
start codon, and these will result in amino termini with different
chemical modifications.
[0989] For example, many or most bacterial proteins are synthesized
with an amino terminal amino acid that is a modified form of
methionine, i.e, N-formyl-methionine (fMet). Although the statement
is often made that all bacterial proteins are synthesized with an
fmet initiator amino acid; although this may be true for E. coli,
recent studies have shown that it is not true in the case of other
bacteria such as Pseudomonas aeruginosa (Newton et al., J. Biol.
Chem. 274:22143-22146, 1999). In any event, in E. coli, the formyl
group of fMet is usually enzymatically removed after translation to
yield an amino terminal methionine residue, although the entire
fMet residue is sometimes removed (see Hershey, Chapter 40,
"Protein Synthesis" in: Escherichia Coli and Salmonella
Typhimurium: Cellular and Molecular Biology, Neidhardt, Frederick
C., Editor in Chief, American Society for Microbiology, Washington,
D.C., 1987, Volume 1, pages 613-647, and references cited therein.)
E. coli mutants that lack the enzymes (such as, e.g., formylase)
that catalyze such post-translational modifications will produce
proteins having an amino terminal fmet residue (Guillon et al., J.
Bacteriol. 174:4294-4301, 1992).
[0990] In eukaryotes, acetylation of the initiator methionine
residue, or the penultimate residue if the initiator methionine has
been removed, typically occurs co- or post-translationally. The
acetylation reactions are catalyzed by N-terminal
acetyltransferases (NATs, a.k.a. N-alpha-acetyltransferases),
whereas removal of the initiator methionine residue is catalyzed by
methionine aminopeptidases (for reviews, see Bradshaw et al.,
Trends Biochem. Sci. 23:263-267, 1998; and Driessen et al., CRC
Crit. Rev. Biochem. 18:281-325, 1985). Amino terminally acetylated
proteins are said to be "N-acetylated," "N alpha acetylated" or
simply "acetylated."
[0991] Another post-translational process that occurs in eukaryotes
is the alpha-amidation of the carboxy terminus. For reviews, see
Eipper et al. Annu. Rev. Physiol. 50:333-344, 1988, and Bradbury et
al. Lung Cancer 14:239-251, 1996. About 50% of known endocrine and
neuroendocrine peptide hormones are alpha-amidated (Treston et al.,
Cell Growth Differ. 4:911-920, 1993). In most cases, carboxy
alpha-amidation is required to activate these peptide hormones.
[0992] XXI. E. Peptidomimetics
[0993] In general, a polypeptide mimetic ("peptidomimetic") is a
molecule that mimics the biological activity of a polypeptide but
is no longer peptidic in chemical nature. By strict definition, a
peptidomimetic is a molecule that contains no peptide bonds (that
is, amide bonds between amino acids). However, the term
peptidomimetic is sometimes used to describe molecules that are no
longer completely peptidic in nature, such as pseudo-peptides,
semi-peptides and peptoids. Examples of some peptidomimetics by the
broader definition (where part of a polypeptide is replaced by a
structure lacking peptide bonds) are described below. Whether
completely or partially non-peptide, peptidomimetics according to
this invention provide a spatial arrangement of reactive chemical
moieties that closely resembles the three-dimensional arrangement
of active groups in the polypeptide on which the peptidomimetic is
based. As a result of this similar active-site geometry, the
peptidomimetic has effects on biological systems that are similar
to the biological activity of the polypeptide.
[0994] There are several potential advantages for using a mimetic
of a given polypeptide rather than the polypeptide itself. For
example, polypeptides may exhibit two undesirable attributes, i.e.,
poor bioavailability and short duration of action. Peptidomimetics
are often small enough to be both orally active and to have a long
duration of action. There are also problems associated with
stability, storage and immunoreactivity for polypeptides that are
not experienced with peptidornimetics.
[0995] Candidate, lead and other polypeptides having a desired
biological activity can be used in the development of
peptidomimetics with similar biological activities. Techniques of
developing peptidomimetics from polypeptides are known. Peptide
bonds can be replaced by non-peptide bonds that allow the
peptidomimetic to adopt a similar structure, and therefore
biological activity, to the original polypeptide. Further
modifications can also be made by replacing chemical groups of the
amino acids with other chemical groups of similar structure. The
development of peptidomimetics can be aided by determining the
tertiary structure of the original polypeptide, either free or
bound to a ligand, by NMR spectroscopy, crystallography and/or
computer-aided molecular modeling. These techniques aid in the
development of novel compositions of higher potency and/or greater
bioavailability and/or greater stability than the original
polypeptide (Dean (1994), BioEssays, 16: 683-687; Cohen and
Shatzmiller (1993), J. Mol. Graph., 11: 166-173; Wiley and Rich
(1993), Med. Res. Rev., 13: 327-384; Moore (1994), Trends
Pharmacol. Sci., 15: 124-129; Hruby (1993), Biopolymers, 33:
1073-1082; Bugg et al. (1993), Sci. Am., 269: 92-98, all
incorporated herein by reference].
[0996] Thus, through use of the methods described above, the
present invention provides compounds exhibiting enhanced
therapeutic activity in comparison to the polypeptides described
above. The peptidomimetic compounds obtained by the above methods,
having the biological activity of the above named polypeptides and
similar three-dimensional structure, are encompassed by this
invention. It will be readily apparent to one skilled in the art
that a peptidomimetic can be generated from any of the modified
polypeptides described in the previous section or from a
polypeptide bearing more than one of the modifications described
from the previous section. It will furthermore be apparent that the
peptidomimetics of this invention can be further used for the
development of even more potent non-peptidic compounds, in addition
to their utility as therapeutic compounds.
[0997] Specific examples of peptidomimetics derived from the
polypeptides described in the previous section are presented below.
These examples are illustrative and not limiting in terms of the
other or additional modifications.
[0998] XXI.E.1. Peptides With A Reduced Isostere Pseudopeptide
Bond
[0999] Proteases act on peptide bonds. It therefore follows that
substitution of peptide bonds by pseudopeptide bonds confers
resistance to proteolysis. A number of pseudopeptide bonds have
been described that in general do not affect polypeptide structure
and biological activity. The reduced isostere pseudopeptide bond is
a suitable pseudopeptide bond that is known to enhance stability to
enzymatic cleavage with no or little loss of biological activity
(Couder, et al. (1993), Int. J. Polypeptide Protein Res.
41:181-184, incorporated herein by reference). Thus, the amino acid
sequences of these compounds may be identical to the sequences of
their parent L-amino acid polypeptides, except that one or more of
the peptide bonds are replaced by an isostere pseudopeptide bond.
Preferably the most N-terminal peptide bond is substituted, since
such a substitution would confer resistance to proteolysis by
exopeptidases acting on the N-terminus.
[1000] XXI.E.2. Peptides With A Retro-Inverso Pseudopeptide
Bond
[1001] To confer resistance to proteolysis, peptide bonds may also
be substituted by retro-inverso pseudopeptide bonds (Dalpozzo, et
al. (1993), Int. J. Polypeptide Protein Res. 41:561-566,
incorporated herein by reference). According to this modification,
the amino acid sequences of the compounds may be identical to the
sequences of their L-amino acid parent polypeptides, except that
one or more of the peptide bonds are replaced by a retro-inverso
pseudopeptide bond. Preferably the most N-terminal peptide bond is
substituted, since such a substitution will confer resistance to
proteolysis by exopeptidases acting on the N-terminus.
[1002] XXI.E.3. Peptoid Derivatives
[1003] Peptoid derivatives of polypeptides represent another form
of modified polypeptides that retain the important structural
determinants for biological activity, yet eliminate the peptide
bonds, thereby conferring resistance to proteolysis (Simon, et al.,
1992, Proc. Natl. Acad. Sci. USA, 89:9367-9371 and incorporated
herein by reference). Peptoids are oligomers of N-substituted
glycines. A number of N-alkyl groups have been described, each
corresponding to the side chain of a natural amino acid.
XXII. Kits
[1004] The invention provides for diagnostic and therapeutic kits
related useful for therapeutic, diagnostic, and research
applications. Exemplary kits are disclosed in U.S. Pat. Nos.
5,773,024; 6,017,721; and 6,232,127 B1. The kits of the invention
incorporate minicells, and/or include methods of using minicells
described herein.
[1005] XXII.A. Diagnostic and Research Use Kit Components
[1006] In one embodiment, the invention relates to kits for
determining the diagnosis or prognosis of a patient. These kits
preferably comprise devices and reagents for measuring one or more
marker levels in a test sample from a patient, and instructions for
performing the assay. Optionally, the kits may contain one or more
means for converting marker level(s) to a prognosis. Such kits
preferably contain sufficient reagents to perform one or more such
determinations.
[1007] More specifically, a diagnostic kit of the invention
comprises any of the following reagents and/or components in any
combination.
[1008] (1) A detectable or detectably labeled first reagent that
binds a ligand of interest. The binding reagent can, but need not,
be an antibody or an antibody derivative comprising a detectable
moiety. The sphingolipid-binding reagent is stored in an openable
container in the kit, or is bound to a surface of a substrate such
that it is accessible to other reagents. Examples of the latter
include test strips.
[1009] (2) If the first reagent in neither detectable nor
detectably labeled, the kit may comprise a detectable or detectably
labeled second reagent that binds to the first reagent (e.g., a
secondary antibody) or which produces a detectable signal when in
close proximity to the first reagent (e.g., as results from
fluorescent resonance energy transfer FRET). In either case, the
signal produced from the second reagent correlates with the amount
of ligand in the sample.
[1010] (3) One or more positive control reagents. Typically, these
reagents comprise a compound that is known to produce a signal in
the assay. In one embodiment, the positive control reagents are
standards, i.e., comprise a known amount of a detectable or
detectably labeled compound, the signal from which may be compared
to the signal from a test sample. In addition to serving as
positive control reagents, they may be used to develop calibration
curves that relate the amount of signal to the known concentration
of a detectable or detectably labeled compound. The signal from a
test sample is compared to the calibration curve in order to
determine what concentration of the detectable or detectably
labeled compound corresponds to the signal from the test sample. In
this embodiment, the kit provides quantitative measurements of the
amount of a ligand in a test sample.
[1011] (4) One or more negative control reagents. Typically, these
control reagents may comprise buffer or another solution that does
not contain any of the detectable or detectably labeled first or
second reagents and should thus not produce any detectable signal.
Any signal that is detected reflects the background level of
"noise" in the assay. Another type of negative control reagent
contains most of the components necessary for the signal of the
assay to be produced, but lacks at least one such component and
therefor should not produce a signal. Yet another type of negative
control reagent contains all of the components necessary for the
signal of the assay to be produced, but also contains an inhibitor
of the process that produced the signal.
[1012] (5) One or more auxiliary reagents for use in the diagnostic
assays of the kit, e.g., buffers, alcohols, acid solutions, etc.
These reagents are generally available in medical facilities and
thus are optional components of the kit. However, these reagents
preferably are included in the kit to ensure that reagents of
sufficient purity and sterility are used, since the resulting
protein conjugates are to be administered to mammals, including
humans, for medical purposes, and to provide kits that can be used
in situations where medical facilities are not readily available,
e.g., when hiking in places located far from medical facilities, or
in situations where the presence of these auxiliary reagents allows
for the immediate treatment of a patient outside of a medical
facility as opposed to treatment that arrives at some later
time).
[1013] (6) Instructions to a person using a kit for its use. The
instructions can be present on one or more of the kit components,
the kit packaging and/or a kit package insert.XXII.B. Therapeutic
Kit Components
[1014] A therapeutic kit of the invention comprises any of the
following reagents and/or components in any combination.
[1015] (1) One or more therapeutic agents.
[1016] (2) If the therapeutic agent(s) are not formulated for
delivery via the alimentary canal, which includes but is not
limited to sublingual delivery, a device capable of delivering the
therapeutic agent through some other routes. One type of device for
parenteral delivery is a syringe that is used to inject the
therapeutic agent into the body of an animal in need of the
therapeutic agent. Inhalation devices may also be used.
[1017] (3) Separate containers, each of which comprises one or more
reagents of the kit. In a preferred embodiment, the containers are
vials contain sterile, lyophilized formulations of a therapeutic
composition that are suitable for reconstitution. Other containers
include, but are not limited to, a pouch, tray, box, tube, or the
like. Kit components may be packaged and maintained sterilely
within the containers.
[1018] (4) Instructions to a person using a kit for its use. The
instructions can be present on one or more of the kit components,
the kit packaging and/or a kit package insert. Such instructions
include, by way of non-limiting example, instructions for use of
the kit and its reagents, for reconstituting lyophilized reagents
or otherwise preparing reagents.
[1019] A preferred kit of the present invention comprises the
elements useful for performing an immunoassay. A kit of the present
invention can comprise one or more experimental samples (i.e.,
formulations of the present invention) and one or more control
samples bound to at least one pre-packed dipstick or ELISA plate,
and the necessary means for detecting immunocomplex formation
(e.g., labelled secondary antibodies or other binding compounds and
any necessary solutions needed to resolve such labels, as described
in detail above) between antibodies contained in the bodily fluid
of the animal being tested and the proteins bound to the dipstick
or ELISA plate. It is within the scope of the invention that the
kit can comprise simply a formulation of the present invention and
that the detecting means can be provided in another way.
[1020] An alternative preferred kit of the present invention
comprises elements useful for performing a skin test. A kit of the
present invention can comprise at least one pre-packed syringe and
needle apparatus containing one or more experimental samples and/or
one or more control samples. A kit according to the invention may
be designed for both diagnostic and therapeutiuc applications. Any
combination of the above elements XX.A.(1)-(6) and XX.B.(1)-(4) may
be used in a kit, optionally with additional reagents, standards,
sample containers, an the like.
XXIII. Immunogenic Minicells
[1021] XXIII.A. In General
[1022] Minicells are used to immunize subjects. An organism is said
to be "immunized" when, after contact with an immunogen, the
organism produces antibodies directed to the immunogen, or has
increased proliferation or activity of cytotoxic and/or helper T
cells, or both. Increased proliferation or activity of T cells may
be particularly desirable in the case of parasites that cause a
decrease in T cell proliferation.
[1023] The use of minicells to present antigens has several
potential advantages. An intact membrane protein can be presented
in its native form on the surface of an immunogenic minicell,
rather than as a denatured protein or as oligopeptides derived from
the amino acid sequence of a membrane protein, which allows for
antibodies to be developed that are directed to epitopes which, due
to protein folding, occur only in the native protein. The minicell
surface may naturally be, or may be modified to be, an adjuvant.
Moreover, pharmacokinetic properties of minicells, as discussed
elsewhere herein, may be improved relative to other forms of
administration.
[1024] The applications of immunogenic minicells include, but are
not limited to, research, prophylactic, diagnostic and therapeutic
applications.
[1025] In research applications, immunogenic minicells are used to
generate antibodies to an antigen displayed on a minicell. Such
antibodies are used to detect an antigen, which may be a chemical
moiety, molecule, virus, organelle, cell, tissue, organ, or
organism that one wishes to study. Classically, such antibodies
have been prepared by immunizing an animal, often a rat or a
rabbit, and collecting antisera therefrom. Molecular biology
techniques can be used to prepare antibodies and antibody
fragments, as is described elsewhere herein. Single-chain antibody
fragments (scFv) may also be identified, purified, and
characterized using minicells displaying a membrane protein or
membrane bound chimeric soluble protein.
[1026] In prophylactic applications, immunogenic minicells are used
to stimulate a subject to produce antibodies and/or activate T
cells, so that the subject is "pre-immunized" before contact with a
pathogen or hyperproliferative cell. Thus, in the case of a
pathogens, the subject is protected by antibodies and/or T cells
that are specifically directed to the pathogen before
infection.
[1027] In therapeutic applications, immunogenic minicells are used
in immunotherapy.
[1028] Certain aspects of the invention involve active
immunotherapy, in which treatment relies on the in vivo stimulation
of the endogenous host immune system to react against pathogens or
tumors due to the administration of agents that cause, enhance or
modulate an immune response. Such agents include, but are not
limited to, immunogens, adjuvants, cytokines and chemokines.
[1029] Other therapeutic applications involve passive
immunotherapy, in which treatment involves the delivery of agents
(such as antibodies or effector cells) that are specifically
directed to an immunogen of a pathogen or a hyperproliferative
cell, and does not necessarily depend on an intact host immune
system. Examples of effector cells include T cells; T lymphocytes,
such as CD8+ cytotoxic T lymphocytes and CD4+ T-helper
tumor-infiltrating lymphocytes; killer cells, such as Natural
Killer (NK) cells and lymphokine-activated killer cells.
[1030] XXIII.B. Hyperproliferative Disorders The immunogenic
minicells of the invention can be used to treat hyperproliferative
disorders by inducing an immune response to an antigen associated
therewith. The term "hyperproliferative disorder" refers to
disorders characterized by an abnormal or pathological
proliferation of cells, for example, cancer, psoriasis, hyperplasia
and the like.
[1031] For reviews of immunotherapy as applied to
hyperproliferative disorders, see Armstrong et al., Cellular
immunotherapy for cancer, BMJ 323:1289-1293, 2001; Evans, Vaccine
therapy for cancer--fact or fiction?, Proc R Cell Physicians Edinb
31:9-16, 2001; Ravindranath and Morton, "Active Specific
Immunotherapy with Vaccines," Chapter 61 in: Holland-Frei Cancer
Medicine, Fifth Edition, Bast, Robert C., et al., editors, B.C.
Decker, Inc., Hamilton, 2000, pages 800-814.
[1032] Types of cancers include without limitation fibrosarcoma,
myxosarcoma, liposarcoma, chondrosarcoma, osteogenic sarcoma,
chordoma, angiosarcoma, endotheliosarcoma, lymphangiosarcoma,
lymphangioendotheliosarcoma, synovioma, mesothelioma, Ewing's
tumor, leiomyosarcoma, rhabdomyosarcoma, colon carcinoma,
pancreatic cancer, breast cancer, ovarian cancer, prostate cancer,
squamous cell carcinoma, basal cell carcinoma, adenocarcinoma,
sweat gland carcinoma, sebaceous gland carcinoma, papillary
carcinoma, papillary adenocarcinomas, cystadenocarcinoma, medullary
carcinoma, bronchogenic carcinoma, renal cell carcinoma, hepatoma,
bile duct carcinoma, choriocarcinoma, seminoma, embryonal
carcinoma, Wilms' tumor, cervical cancer, testicular tumor, lung
carcinoma, small cell lung carcinoma, bladder carcinoma, epithelial
carcinoma, glioma, astrocytoma, medulloblastoma, craniopharyngioma,
ependymoma, pinealoma, hemangioblastoma, acoustic neuroma,
oligodendroglioma, meningioma, melanoma, neuroblastoma,
retinoblastoma, leukemia, lymphoma, multiple myeloma, Waldenstrom's
macroglobulinemia, and heavy chain disease.
[1033] Tumor specific antigens (TSAs), tumor-associated
differentiation antigens (TADAs) and other antigens associated with
cancers and other hyperproliferative disorders include, but are not
limited to, C1 IAC, a human cancer associated protein (Osther, U.S.
Pat. No. 4,132,769); the CA125 antigen, an antigen associated with
cystadenocarcinoma of the ovary, (Hanisch et al., Carbohydr. Res.
178:29-47, 1988; O'Brien, U.S. Pat. No. 4,921,790); CEA, an antigen
present on many adenocarcinomas (Horig et al., Strategies for
cancer therapy using carcinembryonic antigen vaccines, Expert
Reviews in Molecular Medicine, http://www-ermm.cbcu.cam.ac.uk: 1,
2000); CORA (carcinoma or orosomucoid-related antigen) described by
Toth et al. (U.S. Pat. No. 4,914,021); DF3 antigen from human
breast carcinoma (Kufe, in U.S. Pat. Nos. 4,963,484 and 5,053,489);
DU-PAN-2, a pancreatic carcinoma antigen (Lan et al., Cancer Res.
45:305-310, 1985); HCA, a human carcinoma antigen (Codington et
al., U.S. Pat. No. 5,693,763); Her2, a breast cancer antigen
(Fendly et al., The Extracellular Domain of HER2/neu Is a Potential
Immunogen for Active Specific Immunotherapy of Breast Cancer,
Journal of Biological Response Modifiers 9:449-455, 1990); MSA, a
breast carcinoma glycoprotein (Tjandra et al., Br. J. Surg.
75:811-817, 1988); MFGM, a breast carcinoma antigen (Ishida et al.,
Tumor Biol. 10:12-22, 1989); PSA, prostrate specific antigen (Nadji
et al., Prostatic-specific-antigen, Cancer 48:1229-1232, 1981);
STEAP (six transmembrane epithelial antigens of the prostate)
proteins (Afar et al., U.S. Pat. No. 6,329,503); TAG-72, a breast
carcinoma glycoprotein (Kjeldsen et al., Cancer Res. 48:2214-2220,
1988); YH206, a lung carcinoma antigen (Hinoda et al., Cancer J.
42:653-658, 1988); the p97 antigen of human melanoma (Estin et al.,
Recombinant Vaccinia Virus Vaccine Against the Human Melanoma
Antigen p97 for Use in Immunotherapy, Proc. Natl Acad. Sci. USA,
85:1052-1056, 1988); and the melanoma specific antigen described by
Pfreundschuh in U.S. Pat. No. 6,025,191);
[1034] XXIII.B. Intracellular Pathogens
[1035] In certain aspects of the invention, vaccines comprising
immunogenic minicells are used to prevent or treat diseases caused
by intracellular pathogens. Vaccines may be prepared that stimulate
cytotoxic T cell responses against cells infected with viruses
including, but not limited to, hepatitis type A, hepatitis type B,
hepatitis type C, influenza, varicella, adenovirus, herpes simplex
type I (HSV-I), herpes simplex type II (HSV-II), rinderpest,
rhinovirous, echovirus, rotavirus, respiratory syncytial virus,
papilloma virus, papova virus, cytomegalovirus, echinovirus,
arbovirus, huntavirus, coxsackie virus, mumps virus, measles virus,
rubella virus, polio virus, human immunodeficiency virus type I
(HIV-I), and human immunodeficiency virus type II (HIV-II).
Vaccines also may be prepared that stimulate cytotoxic T cell
responses against cells infected with intracellular obligates,
including but not limited to Chlamydia, Mycobacteria and
Rickettsia. Vaccines also may be prepared that stimulate cytotoxic
T cell responses against cells infected with intracellular
protozoa, including, but not limited to, leishmania, kokzidioa, and
trypanosoma.
[1036] The causative agent of Lyme disease, the spirochete Borrelia
burgdorfei, is also of interest. The outer surface proteins (Osps)
A, B and C of B. burgdorfei are known antigens that are
lipoproteins that associate with membranes. Amino-terminal cysteine
residues in Osp proteins are the sites of triacyl lipid
modifications that serve as membrane-anchoring moities. The
N-terminal portions of the Osp proteins are highly conserved and
are preferred portions for display on immunogenic minicells.
[1037] XXIII. C. Eukaryotic Pathogens
[1038] In addition to intracellular pathogens, other eukaryotic
pathogens exist and may also be treated using immunogenic minicells
displayed antigens therefrom. A number of antigens have been used
to develop anti-parasitic vaccines, e.g. the recombinant 45w
protein of Taenia ovis; EG95 oncosphere proteins of Echinococcus
granulosis; cathepsin L antigen of the liver fluke, Fasciola
hepatica; and the H11 antigen of Haemonchus contortus (Dalton et
al., Parasite vaccines--a reality?, Vet Parasitol 98:149-167,
2001). Other eukaryotic pathogens include, but are not limited
to:
[1039] Protozoans, including but not limited to, Entamoeba
histolytica, a pathogenic amoeba that causes amoebic dysentery and
occasionally digests its way through the intestinal wall to invades
other organs, which may cause morbidity; Balantinium coli, a
ciliate that causes diarrhea in humans; Giardia lamblia, a
flagellate that causes diarrhea and abdominal pain, along with a
chronic fatigue syndrome that is otherwise asymptomatic and
difficult to diagnose; Trypanosoma brucei, a hemoflagellate causing
sleeping sickness; and Trypanosoma cruzi, the cause of Chagas
disease);
[1040] Plasmodia, sporozoan obligate intracellular parasites of
liver and red blood cells, including but not limited to P.
falciparum, the causative agent of malaria. Dozens of P. falciparum
antigens have been identified, e.g., CSP-1, STARP, SALSA, SSP-2,
LSA-1, EXP-1, LSA-3, RAP-1, RAP-2, SERA-1, MSP-1, MSP-2, MSP-3,
MSP-4, MSP-5, AMA-1, EBA-175, RESA, GLURP, EMP-1, Pfs25, Pfg27,
Pf35, Pf55, Pfs230, Pfg27, Pfs16, Pfs28 and Pfs45/48.
[1041] Helminthes including but not limited to Ascaris lumbricoides
(roundworm); Enterobius vermicularis (pinworm); Trichuris
trichiuria (whipworm); and Fasciola hepatica (liver fluke);
[1042] Taenia sp. (tapeworms and cestodes);
[1043] Schistosoma (trematodes), such as Schistoma mansoni, which
comprises the Sm32 antigen (asparaginyl endopeptidase), which can
induce antibody formation in mice (Chlichlia et al., DNA
vaccination with asparaginyl endopeptidase (Sm32) from the parasite
Schistosoma mansoni: anti-fecundity effect induced in mice, Vaccine
20:439-447, 2001); and acetylcholinesterase (Arnon et al.,
Acetylcholinesterase of Schistoma mansoni-Functional-correlates,
Protein Science 8:2553-2561, 1999); and
[1044] Ticks and other invertebrates, including but not limited to
insects, arachnids, etc. For example, a description of a vaccine
against the cattle tick Boophilus microplus has been described
(Valle et al., The evaluation of yeast derivatives as adjuvants for
the immune response to the Bm86 antigen in cattle, BMC Biotechnol.
1:2, 2001)
[1045] XXIII.D. Formulation and Adminstration of Immunogenic
Minicells
[1046] Vaccine formulations of immunogenic minicells include a
suitable carrier. Because minicells may be destroyed by digestion,
or prevented from acting due to antibody secretion in the gvut,
they are preferably administered parenterally, including, for
example, administration that is subcutaneous, intramuscular,
intravenous, or intradermal. Formulations suitable for parenteral
administration include aqueous and non-aqueous sterile injection
solutions which may contain antioxidanits, buffers, and solutes
which render the formulation isotonic with the bodily fluid,
preferably the blood, of the individual; and aqueous and
non-aqueous sterile suspensions which may include suspending agents
or thickening agents. The formulations may be presented in
unit-dose or multi-dose containers, for example, sealed ampules and
vials and may be stored in a freeze-dried condition requiring only
the addition of the sterile liquid carrier immediately prior to
use. The vaccine formulation may also include adjuvant systems for
enhancing the immunogenicity of the formulation. Adjuvants are
substances that can be used to augment a specific immune response.
Normally, the adjuvant and the composition are mixed prior to
presentation to the immune system, or presented separately, but
into the same site of the mammal being immunized. Examples of
materials suitable for use in vaccine compositions are provided in
Osol, A., ed., Remington's Pharmaceutical Sciences, Mack Publishing
Co, Easton, Pa. (1980), pp. 1324-1341, which reference is entirely
incorporated herein by reference.
[1047] Compositions comprising immunogenic minicells are injected
into a human or animal at a dosage of 1-1000 ug per kg body weight.
Antibody titers against growth factor are determined by ELISA,
using the recombinant protein and horseradish peroxidase-conjugated
goat anti-human or animal immunoglobulins or other serologic
techniques (e.g., sandwich ELISA). Booster injections are
administered as needed to achieve the desired levels of protective
antibodies and/or T cells.
[1048] Routes and frequency of administration, as well as dosage,
will vary from individual to individual. Between 1 and 10 doses may
be administered for a 52-week period. Preferably, 6 doses are
administered, at intervals of 1 month, and booster vaccinations may
be given periodically thereafter. Alternate protocols may be
appropriate for individual patients. In immunotherapy of
hyperproliferative disorders, a suitable dose is an amount of a
compound that, when administered as described above, is capable of
promoting an anti-tumor immune response. Such response can be
monitored by measuring the anti-tumor antibodies in a patient or by
vaccine-dependent generation of cytolytic effector cells capable of
killing the patient's tumor cells in vitro. Such vaccines should
also be capable of causing an immune response that leads to an
improved clinical outcome (e.g., more frequent remissions, complete
or partial or longer disease-free survival) in vaccinated patients
as compared to non-vaccinated patients.
[1049] The vaccine according to the invention may contain a single
species of immunogenic minicells according to the invention or a
variety of immunogenic minicells, each of which displays a
different immunogen. Additionally or alternatively, immunogenic
minicells may each display and/or express more than one
iummunogen.
[1050] The summary of the invention described above is non-limiting
and other features and advantages of the invention will be apparent
from the following detailed description of the invention, and from
the claims.
EXAMPLES
Example 1
Creation OF A Minicell-Producing Bacterial Cell Line (MC-T7) THAT
Expresses AN Exogenous RNA Polymerase
[1051] In order to maximize the amount of RNA transcription from
episomal elements in minicells, a minicell-producing cell line that
expresses an RNA polymerase specific for certain episomal
expression elements was created. This E. coli strain, designated
MC-T7, was created as follows.
[1052] The P678-54 E. coli strain contains mutations that influence
cell division and induce the production of minicells (Adler et al.,
Proc. Natl. Acad. Sci. 57:321-326 (1967), Allen et al., Biochem.
Biophys. Res. Communi. 47:1074-1079 (1972), Hollenberg et al., Gene
1:33-47 (1976)). The P678-54 strain is resistant to Lambda phage
due to a mutation in the malT gene (Gottesman, Bacteriophage
Lambda: The Untold Story. J. Mol. Biol. 293:177-180, 1999;
Friedman, Interactions Between Bacteriophage Lambda and its
Escherichia Coli Host. Curr. Opin. Genet. Dev. 2:727-738, 1992).
Thus, as an initial step, the P678-54 strain was altered so as to
be sensitive to Lambda phage so that it could form lysogens of
Lambda-DE3 (see below). Wildtype MalT-encoding sequences were
restored via a HFR (high frequency recombination) conjugation
protocol using the G43 E. coli strain (CGSC stain 4928).
[1053] Recipient (P678-54) and donor (G43:BW6169) strains were
grown overnight in 10 mL of LB media (10 g NaCl, 10 g select
peptone 140, and 5 g yeast extract in one liter ddH20). The samples
were centrifuged and then concentrated in about 0.2 mL of LB media.
The concentrated samples were combined and incubated with slow
rotation for 30 minutes at 30.degree. C., and were then plated on
LB agar plates that contained streptomycin (50 .mu.g/mL) and
tetracycline (50 .mu.g/mL). (Ampicillin, streptomycin,
tetracycline, and all other chemicals were purchased from Sigma
Chemical (St. Louis, Mo.) unless otherwise indicated.) Recipient
cells were resistant to streptomycin and donor cells were resistant
to tetracycline; only conjugates, which contained both resistance
genes, were able to grow on the LB agar plates that contained
streptomycin (50 .mu.g/mL) and tetracycline (50 .mu.g/mL).
[1054] Putative conjugates were screened for Lambda phage
sensitivity using a cross streak technique, in which putative
colonies were cross-streaked on an LB agarose plate (streptomycin,
50 .mu.g/mL, and tetracycline, 50 .mu.g/mL) that had been streaked
with live Lambda phage. The streaked conjugate colonies were
streaked perpendicular to the Lambda phage streak; if a conjugate
was sensitive to Lambda phage infection then, upon contact with the
Lambda phage streak, there was cell lysis and thus less or no
bacterial growth. Thus, in the case of conjugates that were
sensitive to Lambda phage, there was deceased bacterial growth
"downstreak" from the phage streak.
[1055] The conjugate E. coli that were found to be sensitive to
Lambda phage infection were then used to create Lambda lysogens.
Lysogenization is a process during which Lambda phage incorporates
its genome, including exogenous genes added thereto, into a
specific site on the chromosome of its E. coli host cell.
[1056] The DE3 gene, which is present in the genome of the Lamda
phage used to create lysogens, encodes RNA polymerase from
bacteriophage T7. Lysogenation was carried out using the
DE3-Lysogenation kit (Novagen, Madison, Wis. essentially according
to the manufacturer's instructions. A T7 polymerase dependent
tester phage was used to confirm the presence and expression of the
DE3 gene on the bacterial chromosome. The T7-dependent tester phage
can only form plaques on a baterial known in the presence of T7
polymerase. The phage uses a T7 promoter for expression of its
essential genes. Therefore in a plaque-forming assay only cells
which express T7 polymerase can be lysed by the tester phage and
only these cells will allow for the formation of plaques. As is
described in more detail herein, episomal expression elements that
are used in minicells may be designed such that transcription and
translation of a cloned gene is driven by T7 RNA polymerase by
utilizing expression sequences specific for the T7 RNA
polymerase.
Example 2
Cloning OF Rat EDG-1 INTO THE PCAL-C Expression Vector
Materials
[1057] Taq Polymerase, PCR Buffers, and PCR reagents were purchased
from Roche Molecular Biochemicals (Indianapolis, Ind. All
restriction enzymes were purchased from Gibco BRL (Grand Island,
N.Y. and Stratagene (La Jolla, Calif. QIAprep mini and maxi kits,
PCR purification Kits, RNeasy miniprep kits, and the One Step
RT-PCR Kit were purchased from QIAGEN (Valencia, Calif. The
Geneclean Kit was purchased from BIO 101 (Carlsbad, Calif. IPTG
(isopropy-beta-D-thiogalactopyranoside), T4 DNA Ligase, LB Media
components and agarose were purchased from Gibco BRL. The pCAL-c
prokaryote expression vector and competent cells were purchased
from Stratagene.
[1058] The pCAL-c expression vector has a structure in which an ORF
may be operably linked to a high-level (but T7 RNA polymerase
dependent) promoter, sequences that bind the E. coli Lac repressor,
and the strong T7 gene 10 ribosome-binding site (RBS). The Lacd
repressor is also encoded by an expressed from te pCAL-c vector. As
long as it is bound to its recognition sequences in the pCAL-c
expression element, the lac repressor blocks transcription from the
T7 promoter. When an inducing agent, such as IPTG is added, the lac
repressor is released from its binding sites and transcription
proceeds from the T7 protmoter, provided the T7 RNA polymerase is
present. After induction, the cloned and expressed protein may
constitute the majority of newley expressed cellular proteins due
to the efficient transcription and translation processes of the
system.
Amplification
[1059] The first step in cloning rat Edg-1 (rEDG-1) into an
expression vector was to design primers for amplification via PCR
(polymerase chain reaction). PCR primers were designed using the
rat Edg-1 sequence (Nakajima et al., Biophy, J. 78:319A, 2000) in
such a manner that they contained either sites for NheI (GCTAGC) or
BamHI (GGATCC) on their five prime ends. The upstream primer had
the sequence of SEQ ID NO:31. The three prime downstream primer
(SEQ ID NO:32) also contained a stop codon, as the pCAL-c vector
contains a Calmodulin Binding Protein (CBP) "tag" at its carboxyl
terminus which was not intended to be incorporated into the rat
Edg-1 polypeptide in this expression construct. The primer and
resulting PCR products were designed so that the five prime end of
the rat Edg-1 ORF was in frame with the methionine start codon
found in the pCAL-c vector.
[1060] Oligonucleotide Primer Sequences for Cloning into
PCAL-C:
6 Edg1/pCAL-c construct primers: Upstream primer
5'-AATTGCTAGCTCCACCAGCATCCCAGTGGTTA-3' (SEQ ID NO:31) Downstream
primer 5'-AATTGGATCCTTAAGAAGAAGAATTGACGTTT-3' (SEQ ID NO:32)
Edg1/CBP fusion construct primers: Upstream primer
5'-AATTGCTAGCTCCACCAGCATCCCAGTGGTTA-3' (SEQ ID NO:31) Downstream
primer 5'-AATTGGATCCAGAAGAAGAATTGACGTTTCCA-3' (SEQ ID NO:33)
Edg1/His6 construct primers: Upstream primer
5'-AATTGCTAGCTCCACCAGCATCCCAGTGGTTA-3' (SEQ ID NO:31) Downstream
primer 5'-AATTGGATCCTTAATGATGATG- ATGATGATGAGAGAAGAATTGACGTTTCC-3'
(SEQ ID NO:34) Edg3/rtPCR primers: Upstream primer
5'-TTATGGCAACCACGCACGCGCAGG-3' (SEQ ID NO:35) Downstream primer
5'-AGACCGTCACTTGCAGAGGAC-3' (SEQ ID NO:36) Edg3/pCAL-c construct
primers: Upstream primer 5'-AATTGCTAGCACGCACGCGCA- GGGGCACCCGC-3'
(SEQ ID NO:37) Downstream primer
5'-AATTGGTACCTCACTTGCAGAGGACCCCATTCTG-3' (SEQ ID NO:38) Edg3/His6
construct primers: Upstream primer
5'-AATTGCTAGCACGCACGCGCAGGGGCACCCGC-3' (SEQ ID NO:39) Downstream
primer 5'-AATTGGTACCTCAATGATGATGATGATGATGCTTGCAGAGGACCC- CATTCTG-3'
(SEQ ID NO:16) GFP/pCAL-c construct primers: Upstream primer
5'-GGTCGCCACCATGGTGAGCAA-3' (SEQ ID NO:40) Downstream primer
5'-TTAAGGATCCTTACTTGTACAGCTCGTCCAT-3- ' (SEQ ID NO:41) GFP/CBP
construct primers: Upstream primer 5'-GGTCGCCACCATGGTGAGCAA-3' (SEQ
ID NO:42) Downstream primer 5'-TTAAGGATCCCTTGTACAGCTCGTCCATGCC-3'
(SEQ ID NO:43)
[1061] Notes:
[1062] Restriction endonuclease sites are underlined
[1063] Stop codons are double underlined
[1064] The primers were used to amplify the rEdg-1 DNA ORF using
the polymerase chain reaction (PCR). The template used for
amplification was mRNA isolated from rat muscle tissue using the
RNeasy Miniprep Kit (Qiagen) and was carried out essentially
according to the manufacturer's protocol. Both the rtPCR and PCR
amplification steps were carried out in a single reaction using the
One Step RT-PCR Kit (Qiagen). The resulting rat Edg-1 PCR fragment
was purified using the PCR Purification Kit (Qiagen). The amplified
double stranded rEdg-1 DNA sequence contained the NheI site at the
5-prime end and the BamHI site at the 3-prime end. This amplified
rEdg-1 fragment was used for cloning into the pCAL-c expression
vector.
[1065] The pCAL-c expression vector contains NcoI, NheI, and BamHI
restriction sites in its multiple cloning site. In order to insert
rEdg-1-encoding sequence into the expression vector, the rEdg-1 PCR
fragment and the pCAL-c expression vector were digested with NheI
and BamHI restriction enzymes for one hour at 37.degree. C. The
reaction mixture for the digestion step consisted of 1 .mu.g of
DNA, 1.times. restriction buffer, and 1 .mu.L of each enzyme. The
reaction mixture was brought to a final volume of 20 .mu.L with
ddH.sub.2O (dd, double distilled). After 45 minutes, 1 .mu.L of
Calf Intestine Alkaline Phosphatase (CIAP) was added to the pCAL-c
reaction mixture in order to remove the terminal phosphates from
the digested plasmid DNA. The reactions were incubated for an
additional 15 minutes at 37.degree. C. The digested DNA samples
were then run on a 1% TAE (Tris-acetate/EDTA electrophoresis
buffer) agarose gel at 130 volts for 45 minutes. The bands were
visualized with UV light after the gel was stained with ethidium
bromide.
[1066] The appropriate bands were cut out of the gel for
purification using the Geneclean Kit (BIO101). The Purified DNA
fragments were then quantified on a 1% TAE agarose gel. For the
ligation reaction, ratios of insert to vector of 6:1 and 3:1 were
used. A negative control comprising vector only was also included
in the ligation reactions. The reaction mixtures contained insert
and vector DNA, 4 .mu.L Ligase buffer, and 2 .mu.L Ligase. The
reaction was brought up to a final volume of 20 .mu.L with
ddH.sub.2O. The ligation was carried out at room temperature for
about 2 hours. Ten (10) .mu.L of the ligation reaction mixture was
used for subsequent transformation steps.
[1067] Ligated DNA was introduced into Epicurian Coli XL1-Blue
competent cells using the heat shock transformation technique as
follows. The ligation mixture was added to 100 .mu.L of competent
cells, placed on ice, and was incubated for about 30 minutes. The
cells were then heat shocked at 37.degree. C. for 1 minute and put
back on ice for 2 minutes. Following heat shock, 950 .mu.L of room
temperature LB media was added to the cells and the cells were
shaken at 37.degree. C. for 1 hour. Following the 1-hour agitation
the cells were pelleted for one minute at 12000 rpm in a Eppendorf
5417C microcentrifuge. The supernatant was carefully poured off so
that about 200 .mu.L remained. The cells were then resuspended in
the remaining LB media and spread on 100.times.15 mm LB agarose
plates containing 50 .mu.g/mL ampicilin. The plates were incubated
overnight at 37.degree. C. Colonies were counted the following day,
and the ratio of colonies between the negative control and the
ligated samples was determined. A high ratio of the number of
colonies when the ligation mixture was used to transform cells, as
contrasted to the number of negative control colonies indicated
that the cloning was successful. Transformed colonies were
identified, isolated, and grown overnight in LB media in the
presence of ampicillin. The resulting bacterial populations were
screened for the presence of the Edg-1-pCAL-c expression
construct.
[1068] Plasmid DNA was isolated from the cells using the QIAprep
Spin Miniprep Kit (Qiagen). Isolated Edg-1-pCAL-c constructs were
screened using the restriction enzyme ApaI, which digests the
Edg-1-pCAL-c construct at two different sites: one in the Edg-1
coding sequence and one in the pCAL-c vector itself. The plasmid
preparations were digested with ApaI electrophoresed on a 1% TAE
agarose gel and visualized using uv light and ethidium bromide
staining. The predicted sizes of the expected DNA fragments were
2065 bp and 4913 bp. As shown in FIG. 3, bands of the predicted
size were present on the gel. The entire Edg-1-pCAL-c construct was
sequenced in order to confirm its structure. This expression
construct, a pCAL-c derivative that contains the rat Edg-1 ORF
operably linked to a T7 promoter and lac repressor binding sites,
is designated "prEDG-1" herein.
Example 3
Construction OF Rat EDG-1-CBP Fusion Protein
[1069] In order to detect rat Edg-1 protein expression, rEdg-1
coding sequences were cloned into the pCAL-c vector in frame with a
CBP fusion tag. The cloning strategy for the rEdg-1-CBP construct
was performed essentially as described for the Edg-1-pCAL-c
construct with the following differences. The PCR primers (SEQ ID
NOS 3 and 5) were as described for the Edg-1-pCAL-c cloning except
for the omission of the stop codon in the downstream primer (SEQ ID
NO:33). The removal of the stop codon is required for the
construction of the Edg-1-CBP fusion protein. The pCAL-c vector is
designed so that, when the BamHI site is used for insertional
cloning, and no stop codon is present in an ORF inserted into the
pCAL-c expression vector the cloned ORF will be in-frame with the
CBP fusion tag. Because the three prime downstream primer did not
contain a stop codon, a CBP fusion tag could be cloned in-frame
with the Edg-1 ORF. Other cloning steps were performed essentially
as described before. The resulting plasmid, a pCAL-c derivative
that comprises an ORF encoding a rat Edg-1-CBP fusion protein
operably linked to a T7 promoter and lac repressor binding sites,
is designated "prEDG-1-CBP" herein.
Example 4
Cloning OF A His-TAGGED RAT EDG-1 INTO PCAL-C Expression Vector
[1070] The rEdg-1 protein was manipulated to generate a fusion
protein having a 6xHis tag at its carboxyl terminus. A "6xHis tag"
or "His tag" is an amino acid sequence consisting of six contiguous
histidine residues that can be used as an epitope for the binding
of anti-6xHis antibodies, or as ligand for binding nickel atoms.
The His-tagged rEdg-1 fusion protein is used to detect rEdg-1
protein expression in the minicell expression system
environment.
[1071] The rEdg-1-6xHis construct was cloned using the strategy
described above for the construction of the rEdg-1-pCAL-c
expression construct (prEDG-1), with the upstream primer having the
sequence of SEQ ID NO:3, but with the exception that the three
prime downstream primer (SEQ ID NO:34) was designed to contain six
histidine codons followed by a stop codon. The 18 base pair 6xHis
tag was incorporated into the carboxyl terminus of the Edg-1
protein as expressed from the pCAL-c vector. Subsequent cloning
procedures (PCR, restriction digest, gel purification, ligation,
transformation, etc.) were performed as described previously for
the Edg-1-pCAL-c construct (prEDG-1). The resulting plasmid, a
pCAL-c derivative that comprises an ORF encoding a carboxy-terminal
His-tagged rat Edg-1-CBP fusion protein operably linked to a T7
promoter and lac repressor binding sites, is designated
"prEDG-1-6xHis"herein.
Example 5
Amplification and Cloning OF Rat EDG-3 Sequences
[1072] The Edg-3 full length coding sequence was amplified via PCR
from rat skeletal muscle mRNA using primers (SEQ ID NOS:35 and 36)
designed from the known mouse sequence (Genbank accession
NM.sub.--010101). The mRNA used as a template for the amplification
reaction was isolated using the RNeasy Miniprep Kit (Qiagen). Both
the rtPCR and PCR amplification steps were carried out in a single
reaction using the One Step RT-PCR Kit (Qiagen). The rEdg-3 PCR
products were visualized with UV after electrophoresis in 1% TAE
agarose gels and ethidium bromide staining.
[1073] The predicted size of the amplified PCR products is 1145
base pairs. An appropriately-sized DNA band was isolated from the
TAE gel and purified using the Geneclean Kit (BIO101). The purified
band was ligated to the pCR3.1 vector using the TA-cloning kit
(Invitrogen). Other cloning steps were carried out as described
previously for the cloning of the rEdg-1-pCAL-c construct
(prEDG-1)with the exception that the samples were screened using
the EcoRI restriction enzyme. The expected sizes of the digested
bands were 1145 base pairs and 5060 base pairs. Positive clones
were analyzed by automated sequencing. The nucleotide sequences
were analyzed using BLAST searches from the NCBI web site
(www.ncbi.nlm.nih.gov/). The predicted full length rat Edg-3 amino
acid sequence was assembled from the nucleotide sequencing data
using in silico translation. The pCR3.1 vector comprising the rat
Edg-3 ORF is designated "pCR-rEDG-3" herein.
Example 6
Cloning of Rat EDG-3 Coding Sequences into the PCAL-C Expression
Vector
[1074] In order to express it in the minicell expression system,
the rat Edg-3 ORF was cloned into the pCAL-c expression vector. The
cloning strategy used was as described above for the cloning of the
rat Edg-1 gene into the pCAL-c vector with the following
exceptions. The primers used for PCR amplification were designed
from the rat Edg-3 sequence and contained sites for the restriction
enzymes NheI and KpnI (GGTACC). The NheI site was added to the five
prime upstream primer (SEQ ID NO:37) and the KpnI site was added to
the three prime downstream primer; SEQ ID NO:38). The NheI and KpnI
restriction enzymes were used for the digestion reaction. The
reaction mixture for the digestion step consisted of 1 .mu.g of
DNA, 1.times. restriction buffer (provided with the enzyme), and 1
.mu.L of each enzyme. Plasmid preparations were screened by
digestion with NheI and KpnI. The digested plasmid DNA was
electrophosesed on a TAE agarose gel and visualized by UV after
staining with ethidium bromide. The resultant band sizes were
predicted to be 1145 base pairs and 5782 base pairs. The positive
plasmid clones were analyzed with automated sequencing. The
resulting plasmid, a pCAL-c derivative that comprises an ORF
encoding a rat Edg-3 protein operably linked to a T7 promoter and
lac repressor binding sites, is designated "pEDG-3" herein.
Example 7
Cloning of a His-tagged Rat EDG-3 into the PCAL-c Expression on
vector
[1075] In order to detect expression of the rat Edg-3 protein in
the minicell expression system, the rat Edg-3 coding sequence was
manipulated so as to contain a 6xHis tag at the carboxyl terminus
of the protein. The cloning strategy used to create this construct
was essentially the same as described above for the rEdg-3-pCAL-c
(prEDG-3) construct cloning, with the upstream primer having the
sequence of SEQ ID NO:37, with the exception that the three-prime
downstream primer (SEQ ID NO:18) was designed to contain a 6xHis
coding sequence followed by a stop codon, which allowed for the
incorporation of the 6xHis amino acid sequence onto the carboxyl
terminus of the Edg-3 receptor protein. Other cloning and screening
steps were performed as described above. The resulting plasmid, a
pCAL-c derivative that comprises an ORF encoding a carboxy-terminal
His-tagged rat Edg-3 fusion protein operably linked to a T7
promoter and lac repressor binding sites, is designated
"prEDG-3-6xHis" herein.
Example 8
GFP Cloning into PCAL-C Expression Construct
[1076] Cloning of GFP-encoding nucleotide sequences into the pCAL-c
vector was performed in order to produce an expression construct
having a reporter gene that can be used to detect protein
expression (GFP; green flourescent protein). The cloning strategy
used was essentially the same as the cloning strategy described
above with the following exceptions. The template used for PCR
amplification was the peGFP plasmid "construct" (GFP construct sold
by Clontech). The primers used for amplification were designed from
the GFP coding sequence and contained sites for the restriction
enzymes NcoI and BamHI. The NcoI site was added to the five prime
upstream primer (SEQ ID NO:40) and the BamHI site was added to the
three prime downstream primer; see SEQ ID NO:41) The NcoI and BamHI
restriction enzymes were used for the digestion reaction. The
reaction mixture for the digestion step consisted of 1 82 g of DNA,
1.times. restriction buffer (provided with the enzyme), and 1 .mu.L
of each enzyme. The screening of the plasmid preparations was
carried out using NcoI and BamHI. Digested plasmid preparations
were electrophoresed and visualized on TAE agarose gels with UV
after staining with ethidium bromide. Restriction products having
the predicted sizes of 797 and 5782 base pairs were seen. Positive
plasmid clones were sequenced using an automated sequencer. The
resulting plasmid, a pCAL-c derivative that comprises an ORF
encoding a rEdg-3-GFP fusion protein operably linked to a T7
promoter and lac repressor binding sites, is designated
"prEDG-3-GFP" herein.
Example 9
Design Construction of Control Expression Elements
[1077] Control expression elements used to detect and quantify
expression of proteins in minicells were preposed. These controls
direct the expression of detectable proteins. An expression element
used as positive control is pPTC12, which is supplied with the
pCAL-c expression vector from Stratagene. This construct contains
an ORF encoding a fusion protein comprising beta-galactosidase
linked to CBP. Induction of expression of pTC12 should result in
the production of a protein of about 120 kD, and this protein is
detected via its enzymatic activity or by using antibodies directed
to epitopes on the beta-galactosidase or CBP polypeptide.
[1078] A GFP fusion construct was created and used as a positive
control for the CBP detection kit. This construct was a positive
control for induction of protein expression in the minicell
expression system. The cloning strategy used to create the
construct was essentially the same as that used for the cloning of
the GFP into the pCAL-c expression vector, with the exception that
the three prime downstream primer did not contain a stop codon;
this allowed for the in frame incorporation of the CBP fusion tag
to the GFP protein. The upstream primer had the sequence of SEQ ID
NO:42, and the downstream primer had the sequence SEQ ID NO:43. The
nucleotide sequence of the expression element was confirmed using
an automated sequencer. The resulting plasmid, a pCAL-c derivative
that comprises an ORF encoding GFP operably linked to a T7 promoter
and lac repressor binding sites, is designated "pGFP-CBP"
herein.
Example 10
Introduction of PCAL-C Expression Constructs into the MC-T7
Escherichia coli Strain
[1079] The MC-T7 E. coli strain was made competent using the
CaCl.sub.2 technique. In brief, cells were grown in 40 mL LB medium
to an OD.sub.600 of 0.6 to 0.8, and then centrifuged at 8000 rpm
(7,700 g) for 5 min at 4.degree. C. The pellet was resuspended in
20 mL of cold CaCl.sub.2 and left on ice for five minutes. The
cells were then centrifuged at 8000 rpm (7,700 g) for 5 min at
4.degree. C. The cell pellet was resuspended in 1 mL of cold
CaCl.sub.2 and incubated on ice for 30 min. Following this
incubation 1 mL of 25% glycerol was added to the cells and they
were distributed and frozen in 200 .mu.L aliquots. Liquid nitrogen
was used to freeze the cells. These cells subsequently then used
for the transformation of expression constructs.
Example 11
Preparation of Minicells
[1080] To some degree, the preparation of minicells varied
according to the type of expression approach that is used. In
general, there are two such approaches, although it should be noted
from the outset that these approaches are neither limiting nor
mutually exclusive. One approach is designed to isolate minicells
that already contain an expressed therapeutic protein or nucleic
acid. Another approach is designed to isolate minicells that will
express the protein or nucleic acid in the minicell following
isolation.
[1081] E. coli are inoculated into bacterial growth media (e.g.,
Luria broth) and grown overnight. After this, the overall protocol
varies with regards to methods of induction of expression. The
minicell producing cultures used to express protein post isolation
are diluted and grown to the desired OD.sub.600 or OD450, typically
in the log growth phase of bacterial cultures. The cultures are
then induced with IPTG and then isolated. The IPTG concentration
and exposure depended on which construct was being used, but was
usually about 500 .mu.M final for a short time, typically about 4
hours. This treatment results in the production of the T7
polymerase, which is under control of the LacUVR5 promoter, which
is repressed by the LacI repressor protein. IPTG relieves the LacI
repression and thus induces expression from the LacUVR5 promoter
which controls expression of the T7 polymerase from the chromosome.
This promoter is "leaky" that is, there is always a basal level of
T7 polymerase which can be selected for or against so that the
induction before isolation is not required. (This induction step is
not required if a non-T7 expression system is used, as the reason
for this step is to express the T7 RNA polymerase in the
minicell-producing cells so that the polymerase and molecules
segregate with the minicell.)
[1082] The E. coli cultures that produce minicells containing a
therapeutic protein or nucleic acid have different induction
protocols. The overnight cultures are diluted as described above;
however, in the case of proteins that are not toxic to the parent
cells, this time the media used for dilution already contains IPTG.
The cultures are then grown to mid-log growth and minicells are
isolated. These cultures produce the therapeutic protein or nucleic
acid as they grow, and the minicells derived therefrom contain the
therapeutic protein or nucleic acid.
[1083] Alternatively or additionally, IPTG is added and expression
is induced after the isolation of minicells. In the case of
non-toxic proteins or nucleic acids that are expressed from
expression elements in minicells, this treatment enhances
production of the eposimally encoded gene product. In the case of
toxic gene products induction post-isolation is preferred.
Example 12
Minicell Isolation
[1084] Minicells were isolated from the minicell producing MC-T7
strain of E. coli using centrifugation techniques. The protocol
that was used is essentially that of Jannatipour et al.
(Translocation of Vibrio Harveyi N,N'-Diacetylchitobiase to the
Outer Membrane of Escherichia Coli, J. Bacteriol. 169: 3785-3791,
1987) and Matsumura et al. (Synthesis of Mot and Che Products of
Escherichia coli Programmed by Hybrid ColE1 Plasmids in Minicells,
J. Bacteriol. 132:996-1002, 1977).
[1085] In brief, MC-T7 cells were grown overnight at 37.degree. C.
in 2 to 3 mL of LB media containing ampicillin (50 .mu.g/mL),
streptomycin (50 .mu.g/mL), and tetracycline (50 .mu.g/mL)
(ampicillin was used only when growing MC-T7 cells containing a
pCAL-c expression construct). The cells were diluted 1:100 in a
total volume of 100 to 200 mL LB media with antibiotics, and grown
at 37.degree. C. until they reached an OD.sub.600 of 0.4 to 0.6,
which is roughly beginning of the log growth phase for the MC-T7 E.
coli. During this incubation the remainder of the overnight culture
was screened for the presence of the correct expression construct
using the techniques described above. When the cultures reached the
appropriate OD.sub.600 they were transferred to 250 mL GS3
centrifuge bottles and centrifuged (Beckman centrifuge) at 4500 rpm
(3,500 g) for 5 min. At this point the supernatant contains mostly
minicells, although a few relatively small whole cells may be
present.
[1086] The supernatant was transferred to a clean 250 mL GS3
centrifuge bottle and centrifuged at 8000 rpm (11,300 g) for 10
min. The pellet was resuspended in 2 mL of 1.times.BSG
(10.times.BSG: 85 g NaCl, 3 g KH.sub.2PO.sub.4, 6 g
Na.sub.2HPO.sub.4, and 1 g gelatin in 1 L ddH.sub.2O) and layered
onto a 32 mL 5 to 20% continuous sucrose gradient. The sucrose
gradient was made with sucrose dissolved in 1.times.BSG.
[1087] The sucrose gradient was then loaded in a Beckman SW24 rotor
and centrifuged in a Beckman Ultracentrifuge at 4500 rpm (9,000 g)
for 14 min. Following ultracentrifugation a single diffuse band of
minicells was present. The top two thirds of this band was
aspirated using a 10 mL pipette and transferred to a 30 mL Oakridge
tube containing 10 mL of 1.times.BSG. The sample was then
centrifuged at 13,000 rpm (20,400 g) for 8 min. Following
centrifugation, the pellet was resuspended in 2 mL 1.times.BSG, and
the resuspended cells were loaded onto another 5 to 20% sucrose
gradient. This sucrose gradient was centrifuged and the minicells
were collected as described above. The sucrose gradient procedure
was repeated a total of three times.
[1088] Following the final sucrose gradient step the entire
minicell band was collected from the sucrose gradient and added to
a 30 mL Oakridge tube that contained 10 mL of MMM buffer (200 mL
1.times.M9 salts, 2 mL 20% glucose, and 2.4 mL DIFCO Methionine
Assay Medium). This minicell solution was centrifuged at 13,000 rpm
(20,400 g) for 8 min. The pellet was resuspended in 1 mL of MMM
Buffer.
[1089] The concentration of minicells was determined using a
spectrophotometer. The OD.sub.450 was obtained by reading a sample
of minicells that was diluted 1:100.
Example 13
Other Methods to Prepare and Isolate Minicells
[1090] By way of non-limiting example, induction of E. coli
parental cells to form minicells may occur by overexpression of the
E. coli ftsZ gene. To accomplish this both plasmid-based and
chromosomal overexpression constructs were created that place the
ftsZ gene under the control of various regulatory elements (Table
6).
7TABLE 6 REGULATORY CONSTRUCTS CONTROLLING FTSZ EXPRESSION.
Regulatory region inducer [inducer] SEQ ID NO.: Para::ftsZ
Arabinose 10 mM 1, 3 Prha::ftsZ Rhamnose 1 mM 2, 4 Ptac::ftsZ IPTG
30 .mu.M .sup. 5, Garrido et al..sup.a.sup. .sup.aGarrido, T. et
al. 1993. Transcription of ftsZ oscillates during the cell cycle of
Escherichia coli.
[1091] Oligonucleotide Names and PCR Reactions use the Following
Format:
[1092] "gene-1" is N-terminal, 100% homology oligo for chromosomal
or cDNA amplification
[1093] "gene-2" is C-terminal, 100% homology oligo for chromosomal
or cDNA amplification
[1094] "gene-1-RE site" is same sequence as gene-i with additional
residues for remainder of sequence, RE sites, and/or chimeric
fusions.
[1095] "gene-2-RE site" is same sequence as gene-1 with additional
residues for remainder of sequence, RE sites, and/or chimeric
fusions.
[1096] Use "gene-1, 2" combo for chromosomal/cDNA amplification and
"gene-1 RE site, gene-2-RE site" to amplify the mature sequence
from the "gene-1, 2" gel-purified product.
8TABLE 7 OLIGONUCLEOTIDE PRIMER SEQUENCES FOR TABLE 6 CONSTRUCTS
SEQ ID NO.: Primer name 5' to 3' sequence 44 FtsZ-1
CCAATGGAACTTACCAATGACGCGG 45 FtsZ-2 GCTTGCTTACGCAGGAATGCTGGG 46
FtsZ-1-PstI CGCGGCTGCAGATGTTTGAACCAATGGAACTTACCAATGACGCGG 47
FtsZ-2-XbaI GCGCCTCTAGATTATTAATCAGCTTGCTTACGCAGGAATGCTGGG
[1097] Table 7 oligonucleotide sequences are for use in cloning
ftsZ into SEQ ID NO.:1 and 2 (insertions of ftZ behind the
arabinose promotor (SEQ ID NO.: 1) and the rhamnose promotor (SEQ
ID NO.: 2).
9TABLE 8 OLIGONUCLEOTIDE PRIMER SEQUENCES FOR FTSZ CHROMOSOMAL
DUPLICATION CONSTRUCTS SEQ ID NO.: Primer name 5' to 3' sequence 48
Kan-1 GCTAGACTGGGCGGTTTTATGGACAGCAAGC 49 Kan-2
GCGTTAATAATTCAGAAGAACTCGTCAAGAAGGCG 50 Kan-1-X-frt
GCGCCTACTGACGTAGTTCGACCGTCGGACTAGCGAAGT
TCCTATACTTTCTAGAGAATAGGAACTTCGCTAGACTGG GCGGTTTTATGGACAGCAAGC 51
Kan-2-intD-frt CAAGATGCTTTGCCTTTGTCTGAGTTGATACTGGCTTTGG
GAAGTTCCTATTCTCTAGAAAGTATAGGAACTTCGCGTT
AATAATTCAGAAGAACTCGTCAAGAAGGCG 52 AraC-1 CGTTACCAATTATGACAACTTGACGG
53 RhaR-1 TTAATCTTTCTGCGAATTGAGATGACGCC 54 LacI.sup.q-1
GTGAGTCGATATTGTCTTTGTTGACCAG 55 Ara-1-intD
GCCTGCATTGCGGCGCTTCAGTCTCCGCTGCATACTGTCC CGTTACCAATTATGACAACTTGA-
CGG 56 RhaR-1-intD GCCTGCATTGCGGCGCTTCAGTCTCCGCTGCATACTGTC- C
TTAATCTTTCTGCGAATTGAGATGACGCC 57 LacI.sup.q-1-intD
GCCTGCATTGCGGCGCTTCAGTCTCCGCTGCATACTGTCC
TTAATAAAGTGAGTCGATATTGTCTTTGTTGACCAG 58 FtsZ-1-X
GCCTGCATTGCGGCGCTTCAGTCTCCGCTGCATACTGTCC CGTTACCAATTATGACAACTTGA-
CGG
[1098] In like fashion, the ftsZ gene was amplified from SEQ ID
NO.: 1, 2 and Ptac::ftsZ (Garrido, T. et al. 1993. Transcription of
ftsZ oscillates during the cell cycle of Escherichia coli. EMBO J.
957-3965) plasmid and chromosomal constructs, respectively using
the following oligonucleotides:
[1099] For amplification of araC through ftsZ of SEQ ID NO.: 1 use
oligonucleotides:
[1100] AraC-1
[1101] FtsZ-2
[1102] For amplification of rhaR through ftsZ of SEQ ID NO.: 2 use
oligonucleotides:
[1103] RhaR-1
[1104] FtsZ-2
[1105] For amplification of lacI.sup.q through ftsZ of Ptac::ftsZ
(Garrido, T., et al.) use oligonucleotides:
[1106] lacI.sup.q-1
[1107] ftsZ-2
[1108] The above amplified DNA regions were gel-purified and used
as template for the second round of PCR using oligonucleotides
containing homology with the E. coli chromosomal gene intD and on
the other end with random sequence termed "X". Oligonucleotides
used in this round of PCR are shown below:
[1109] For amplification of araC through ftsZ from SEQ ID NO.: 1 to
contain homology to intD and the random X use oligonucleotides:
[1110] AraC-1-intD
[1111] FtsZ-1-X
[1112] For amplification of rhaR through ftsZ from SEQ ID NO.: 2 to
contain homology to intD and the random X use oligonucleotides:
[1113] RhaR-1-intD
[1114] FtsZ-1-X
[1115] For amplification of lacIq through ftsZ from Ptac: :ftsZ to
contain homology to intD and the random X use oligonucleotides:
[1116] LacIq-1-intD
[1117] FtsZ-1-X
[1118] The PCR products from these PCR reactions are as shown
below:
[1119] intD-araC-Ara promotor-ftsZ-"X"
[1120] intD-rhaRS-Rha promotor-ftsZ-"X"
[1121] intD-lacI.sup.q-Ptac promotor-ftsZ-"X"
[1122] To amplify the mature complexes, the following regions were
mixed and amplified with the coupled oligonucleotide sequence
primers: 5
[1123] These expression constructs may be expressed from the
plasmid, placed in single copy, replacing the native ftsZ copy on
the E. coli chromosome (Garrido, T., et al. 1993. Transcription of
ftsZ oscillates during the cell cycle of Escherichia coli. EMBO J.
12:3957-3965), or in duplicate copy retaining the native ftsZ copy
while inserting one of the expression constructs in Table 6 into
the intD gene on the same chromosome. Chromosomal duplications were
constructed using the RED recombinase system (Katsenko, K. A., and
B. L. Wanner. One-Step Inactivation of Chromosomal Genes in
Escherichia coli K-12 Using PCR Products. Proc. Natl. Acad. Sci.
97:6640-6645. 2000) and are shown in SEQ ID NO 3-5. The later
constructs allow native replication during non-minicell producing
conditions, thus avoiding selective pressure during strain
construction and maintenance. Furthermore, these strains provide
defined points of minicell induction that improve minicell
purification while creating conditions that allow strain
manipulation prior to, during, and following minicell production.
By way of non-limiting example these manipulations may be protein
production that the cytoplasmic redox state, modify plasmid copy
number, and/or produce chaperone proteins.
[1124] For minicell production, a minicell producing strain
described in the previous section is grown overnight in Luria broth
(LB) supplemented with 0.1% dextrose, 100 .mu.g/ml ampicillin, and
when using the single-copy ftsZ construct, 15 .mu.M IPTG. All
incubations were performed at 37.degree. C. For minicell induction
only, overnight strains are subcultured {fraction (1/1000)} into
the same media. If minicell induction is to be coupled with
co-expression of other proteins that are controlled by a catabolite
repression-sensitive regulator, dextrose was excluded. Minicell
induction is sensitive to aeration and mechanical forces.
Therefore, flask size, media volume and shake speed is critical for
optimal yields. Likewise, bioreactor conditions must be properly
regulated to optimize these production conditions.
[1125] In shake-flask cultures, strains are grown to early
exponential (log) phase as monitored by optical density (OD) at 600
nm (OD.sub.600 0.05-0.20). (Bioreactor conditions may differ
significantly depending on the application and yield desired). For
minicell induction alone, early log phase cultures are induced with
the appropriate inducer concentration shown in Table 6. For coupled
co-expression, these cultures are induced as shown in Table 6 for
the appropriate minicell regulator, while the coupled protein(s) is
induced with the inducer appropriate for the regulator controlling
the synthesis of that protein. Cultures are grown under the
appropriate conditions and harvested during late log (OD.sub.600
0.8-1.2). Depending on the application, minicell induced cultures
may be immediately chilled on ice prior to purification, or
maintained at room temperature during the harvesting process.
[1126] To separate minicells from viable, parental cells, cultures
are subjected to differential centrifugation (Voros, J., and R. N.
Goodman. 1965. Filamentous forms of Erwinia amylovora. Phytopathol.
55:876-879). Briefly, cultures are centrifuged at 4,500 rpm in a
GSA rotor for 5 min. Supernatants are removed to a fresh bottle and
centrifuged at 8,000 rpm for an additional 10 min to pellet
minicells. Pelleted minicells (containing contaminating parental
cells) are resuspended in 2 ml LB, LBD (LB supplemented with 0.1%
dextrose), Min (minimal M63 salt media) (Roozen, K. J., et al.
1971. Synthesis of ribonucleic acid and protein in
plasmid-containing minicells of Escherichia coli K-12. J.
Bacteriol. 107:21-23), supplemented with 0.5% casamino acids) or
MDT (minimal M63 salt media, supplemented with 0.5% casamino acids,
0.1% dextrose, and thiamine). Resuspended minicells are next
separated using linear density gradients. By way of non-limiting
example, these gradients may contain sucrose (Cohen A., et al.
1968. The properties of DNA transferred to minicells during
conjugation. Cold Spring Harb. Symp. Quant. Biol. 33:635-641),
ficol, or glycerol. For example, linear sucrose gradients range
from 5-20% and are poured in LB, LBD , Minor MDT. Using a SW28
swinging bucket rotor, gradients are centrifuged at 4,500 rpm for
14 min. Banded minicells are removed, mixed with LB, LBD , Minor
MDT, and using a JA-20 rotor are centrifuged at 13,000 rpm for 12
min. Following centrifugation, pellets are resuspended in 2 ml LB,
LBD , Minor MDT and subjected to a second density gradient.
Following the second density separation, banded minicells are
removed from the gradient, pelleted as described, and resuspended
in LB, LBD , Minor MDT for use and/or storage.
[1127] Purified minicells are quantitated using an OD.sub.600
measurement as compared to a standard curve incorporating LPS
quantity, minicell size, and minicell volume. Quantitated minicells
mixtures are analyzed for contaminating, viable parental cells by
plating on the appropriate growth media (Table 9).
10TABLE 9 MINICELL PURIFICATION AND PARENTAL CELL QUANTITATION
Purifi- Total Fold- cation Total cells parental cells MC/PC ratio
purification Before 4.76 .times. 10.sup.11 3.14 .times. 10.sup.11
0.25/1 -- After 1.49 .times. 10.sup.11 6.01 .times. 10.sup.4 2.48
.times. 10.sup.6/1 5.23 .times. 10.sup.6
Example 14
Protoplast Formation
[1128] In order to allow a membrane receptor to be presented to the
outside environment (displayed), minicells are made into
protoplasts. In order to make the integral membrane protein
receptors in the inner membrane more accessible for ligand binding,
the outer membrane and cell wall were removed. The removal of the
outer membrane and cell wall from E. coli whole cells and minicells
to produce protoplasts was performed essentially according to
previously described protocols with a few modifications (Birdsell
et al., Production and Ultrastructure of Lysozyme and
Ethylenediaminetetraacetate-Lysozyme Spheroplasts of Escherichia
coli, J. Bacteriol. 93:427-437, 1967; Weiss et al., Protoplast
Formation in Escherichia Coli, J. Bacteriol. 128:668-670, 1976.
Both minicells and whole cells were processed the same way.
[1129] In brief, the cells were grown to mid-log phase and pelleted
at room temperature (minicells were isolated from cultures in
mid-log phase). The pellet was washed twice with 10 mM Tris.
Following the second wash protoplast production may be performed
using two approaches. In the first approach, following the second
wash, the cells were resuspended in 100 mM Tris (pH 8.0) that
contained 6-20% sucrose and put in a 37.degree. C. waterbath (the
Tris/sucrose buffer was pre-warmed to 37.degree. C.). The volume
used to resuspend the cells was determined by the following
equation: (volume of cells.times.OD.sub.450)/10=resuspension
volume. After a 1 minute incubation, 2 mg/mL lysozyme was added to
a final concentration of 5-100 .mu.g/mL. The samples were then
incubated for 12 minutes at 37.degree. C. while being gently mixed.
Next, 100 mM EDTA (pH 7) was slowly added over a period of 2.5
minutes (amount of EDTA added={fraction (1/00)}-{fraction (1/10)}
volume of cells) followed by a 10 min incubation at 37.degree. C.
The protoplasts are also diluted from 20% sucrose down to either
10% or 5% sucrose, which facilitates the complete removal of the
outer membrane and cell wall. The protoplasts thus generated were
separated from the outer membrane and cell wall using a sucrose
step gradient. A sucrose step gradient does not have a gradual
increase in sucrose percentage; rather, it goes directly from one
percent to the other. For example, protoplasts generated from whole
cells are loaded on a step gradient that is made from 5% and 15%
sucrose. The protoplasts spin through the 15% sucrose but the
debris generated when making the protoplasts does not spin through
the 15% sucrose. The protoplasts are thus separated from the
debris. The second method to prepare protoplasts, following the
second wash, 1.times.10.sup.9 cells were resuspended with 50 mM
Tris, pH 8.0 containing 0.5-50 mM EDTA and 6-20% sucrose. This
mixture was incubated at 37.degree. C. for 10 min. Following
incubation, the mixture was centrifuged at 13,200 RPM in a
microcentrifuge for 2 min. After centrifugation, the pellet was
resuspened in 50 mM Tris, pH 8.0 containing 5-100 .mu.g/ml lysozyme
and 6-20% sucrose. This mixture was incubated at 37.degree. C. for
10 min. Following incubation, the mixture was centrifuged at 13,200
RPM in a microcentrifuge for 2 min, resuspended in 50 mM Tris pH
8.0 containing 6-20% sucrose for use.
[1130] An alternative method to remove contaminating LPS is to use
affinity absorption with an anti-LPS antibody (Cortex). To
accomplish this, the anti-LPS antibody was coated on either an
activated agarose or sepharose matrix (Sigma) or epoxy-coated
magnetic M-450 beads (Dynal). The spheroplast/protoplast mixture
was subjected to the antibody coated matrix either in batch or
using column chromatographic techniques to remove contaminating
LPS. Following exposure, the unbound fraction(s) was collected and
re-exposed to fresh matrix. To monitor the efficiency of the
protoplasting reaction and LPS removal, three constructs were used
(Table 10).
11TABLE 10 PROTOPLAST MONITORING CONSTRUCTS SEQ ID SEQ ID Inducible
Construct NO Plasmid NO protein Inducer PMPX-5 6 pMPX-32 7
.DELTA.phoA Rhamnose PMPX-5 6 pMPX-53 8 phoA Rhamnose PMPX-5 6
pMPX-33 9 toxR-phoA Rhamnose
[1131]
12TABLE 11 OLIGONUCLEOTIDE PRIMER SEQUENCES FOR TABLE 10 CONSTRUCTS
SEQ ID NO.: Primer name 5' to 3' sequence 59 .DELTA.phoA-1
GCCTGTTCTGGAAAACCGGGCTGCTCAGGG 60 .DELTA.phoA-2
GCGGCTTTCATGGTGTAGAAGAGATCGG 61 .DELTA.phoA-1-PstI
CCGCGCTGCAGATGCCTGTTCTGGAAAACCGGGCTGCTCAGGG 62 .DELTA.phoA-2-XbaI
GCGCCTCTAGATTATTATTTCAGCCCCAGAGCGGCTTTCATG GTGTAGAAGAGATCGG 63
PhoA-1 GTCACGGCCGAGACTTATAGTCGC 64 PhoA-2
GCGGCTTTTCATGGTGTAGAAGAGATCGG 65 PhoA-1-PstI
CCGCGCTGCAGATGTCACGGCCGAGACTTATAGTCGC 66 PhoA-2-XbaI
GCGCCTCTAGATTATTATTTCAGCCCCAGAGCCGGCTTTCATG GTGTAGAAGAGATCGG 67
T-phoA-1-PstI CCGCGCTGCAGATGAACTTGGGA- ATCGACTGTTTATTCTGA
TAGCGGTCTTACTTCCCCTCGCAGTATTACTGCTCATGCCTG
TTCTGGAAAACCGGGCTGCTCAGGG 68 T-phoA-2-XbaI
GCGCCTCTAGATTATTATTTCAGCCCCAGAGCGGCTTTCATG GTGTAGAAGAGATCGG
[1132] Oligonucleotides SEQ ID NOS.:59, 60, 61 and 62 were used to
amplify phoA lacking a leader sequence (Apho.DELTA.) form the E.
coli chromosome. Once amplified, this region was inserted into SEQ
ID NO.: 6 using PstI and XbaI to create SEQ ID NO.: 7.
[1133] Oligonucleotides SEQ ID NOS.:63, 64, 65 and 66 were used to
amplify phoA containing a leader sequence (phoA) form the E. coli
chromosome. Once amplified, this region was inserted into SEQ ID
NO.: 6 using PstI and XbaI to create SEQ ID NO.: 8.
[1134] Oligonucleotides SEQ ID NOS.:59, 60, 67 and 68 were used to
amplify phoA lacking a leader sequence (.DELTA.phoA) form the E.
coli chromosome and form a translational fusion between the
transmembrane domain of toxR from Vibrio cholerae. Once amplified,
this region was inserted into ID NO.: 6 using PstI and XbaI to
create SEQ ID NO.: 9.
[1135] By co-expression of minicells and protein, minicells were
prepared that contained cytoplasmic PhoA (pMPX-32 expresses phoA
lacking a leader sequence [.DELTA.phoA]), periplasmic PhoA (pMPX-53
expresses native phoA that exports to the periplasmic space), or
inner membrane-bound PhoA (pMPX-33 expresses phoA lacking a leader
sequence fused to the transmembrane domain (TMD) of the toxR gene
product from Vibrio cholerae). Using these expressed proteins, the
efficiency of minicell protoplasting was monitored (Table 12).
13TABLE 12 EFFICIENCY OF MINICELL PROTOPLAST PREPARATION AND
PURIFICATION Step Location .sup.a .DELTA.PhoA PhoA T-PhoA LPS total
.sup.b Minicell Pellet 100 100 100 100 EDTA/lysozyme Whole 100 100
100 100 1.sup.st Anti-LPS Pellet 80 0 80 30 2.sup.nd Anti-LPS
Pellet 60 0 60 0 .sup.a Measuring the location of protein being
measured using an anti-BAP antibody (Sigma). Pellet refers to the
presence of the expressed protein in the low-speed centrifugation
pellet. These pellets contain only intact cellular bodies. Whole
refers to the reaction mixture prior to low-speed centifugation.
.sup.b Measured using a slot-blot apparatus (Bio-Rad) using the
anti-LPS antibody (Cortex)
[1136] The data suggests that periplasmic PhoA is lost during the
preparation, while both cytoplasmic and membrane-bound PhoA are
retained in a cellular body that lacks LPS. However, during this
process .about.40% of the total minicell content is lost.
Example 15
T7-dependent Induction of Expression
[1137] Expression from the pCAL-c expression vector is driven from
a T7 bacteriophage promoter that is repressed by the LacI gene
product. Transcription of the DNA into mRNA, and subsequent
translation of mRNA into proteins, does not occur as long as the
LacI repressor is bound to the T7 promoter. However, in the
presence of IPTG, the LacI repressor does not bind the T7 promoter.
Thus, induction of expression from pCAL-c sequences is dependent on
the presence of IPTG. Slightly different protocols were used for
the induction of Escherichia coli whole and for the induction of
minicells. Slight differences are also present in the protocols for
induction of minicells for .sup.35S-methionine labeling of proteins
in contrast to those for the induction of minicells for Western
blot analysis. These induction protocols are described bellow.
[1138] For expression in E. coli whole cells, the cells were first
grown overnight in 3 mL of LB and antibiotics. The cultures were
screened for the presence of the desired expression element as
previously described. Cultures containing the desired expression
elements were diluted 1:100 and grown to an OD.sub.600 of between
0.4 to 0.6. The culture size varied depending on the intended use
of the cells. IPTG was then added to a final concentration of 200
.mu.g/mL, and the cells were shaken at 30.degree. C. for 4 hours.
Following the induction, cells were harvested for analysis.
[1139] The induction of minicells was carried out as follows. The
minicells were diluted in MMM buffer to 1 mL total volume according
to the concentration obtained from the isolation procedure
(OD.sub.450 of about 0.5). The cells were then treated with 50
.mu.g/mL of cycloserine for 30 minutes at 37.degree. C. to stop
whole cell growth. Following the cycloserine treatment the cells
were provided with an amino acid, methionine, which the MMM buffer
does not contain. For .sup.35S-labeled protein induction
.sup.35S-methionine was added to the minicell sample whereas, for
unlabeled protein induction unlabeled methionine was added. Fifteen
(15) .mu.Ci of .sup.35S-methionine (Amersham Pharmacia Biotech,
Piscataway, N.J.) was added to the samples for radiolabeling and 5
.mu.mol of methionine was added to the non-labeled minicell
samples. Two hundred (200) .mu.g/mL IPTG was also added to the
minicell samples, which were then shaken at 30.degree. C. for about
4 hours. Following induction, the minicells were harvested for
further preparation or analysis.
Example 16
Western Blot Analysis
[1140] The CBP detection kit was purchased from Stratagene. SDS
running buffer, 10% Tris-HCl ready gels, Kaleidoscope Pre-stained
Standards, and Laemmli Sample Buffer were purchased from BIO RAD
(Hercules, Calif.). GFP (FL) HRP antibodies were purchased from
Santa Cruz Biotechnology (Santa Cruz, Calif.). Edg-3CT antibody an
antibody directed to the carboxy terminus of was purchased from
Exalpha Biologicals (Boston, Mass.). Anti-6xHis antibody,
positrope, and the WesternBreeze Kit were purchased from Invitrogen
(Carlsbad, Calif.). Protocols were carried out essentially
according to the manufacturer's instructions unless otherwise
indicated.
[1141] Three different Western blot protocols were used to detect
protein expression in both a minicell expression system and in a
whole cell expression system. For both systems, the SDS-PAGE gel
and the transfer protocols were essentially as follows. The samples
were denatured by diluting the samples 1:1 in Laemmli buffer
(BIORAD) and then sonicated for 10 min. The denatured samples were
loaded onto a 10% Tris-Glycine gel (BIORAD) and electrophoresed at
130 V for about 1.5 hours in 1.times.SDS running buffer (BIORAD).
The electrophoresed proteins were electrotransferred to
nitrocellulose membranes at 0.5 Amps for 1.5 hours in Transfer
Buffer (5.8 g Tris, 2.9 g glycine, 200 mL methanol, and 3.7 mL of
10% SDS). The nitrocellulose membranes comprising the transferred
proteins were used for Western bloting.
[1142] GFP Western blots were carried out as follows. The
nitrocellulose membrane was blocked for 2 hours with 5% milk in
PBST (PBS buffer with 0.05% Tween). Following the blocking step the
nitrocellulose membrane was washed twice with PBST. For the
detection of GFP protein, an anti-GFP-HRP conjugated antibody
(Santa Cruz Biotechnology) was used at a dilution of 1:3000 in PBST
(HRP, horse radish peroxidase). The nitrocellulose membrane was
incubated in the anti-GFP-HRP antibody solution for one hour and
then washed twice with PBST. GFP proteins on the nitrocellulose
membrane were detected and visualized using the ECL system
(Amersham).
[1143] The His-tagged Edg-1 and Edg-3 proteins were detected using
a mouse anti-6xHis antibody from Invitrogen and the WesternBreeze
chemoluminecent Kit (Invitrogen). The antibody was diluted 1:4000
in buffers provided by the WesternBreeze Kit. The WesternBreeze
immunoblot was carried out essentially according to the
manufacturer's protocol. The Edg-1-CBP and GFP-CBP fusion proteins
were detected using the CBP detection Kit (Stratagene). All
antibodies and substrates were provided in the Kit. FIG. 3 is a
photo of the Western hybridization results showing the presence of
Edg-1-6xHis and Edg-3-6xHis in minicells and parent cells.
Example 17
Methods to Induce Expression
[1144] Expression in minicells may proceed following purification
of minicells and/or minicell protoplasts from parental cells and
LPS constituents, repectively. However, for some applications it is
suitable to co-express proteins of interest with minicell
induction. For these approaches, one may use the protocol described
in EXAMPLE 13 for expression of the phoA constructs. By way of
non-limiting example, either of these approaches may be
accomplished using one or more of the following expression
constructs (Table 13).
14TABLE 13 EXPRESSION CONSTRUCTS Regulatory SEQ ID Plasmid
element(s) inducer Plasmid NO.: pMPX-5 rhaRS Rhamnose pUC-18 6
pMPX-7 uidR .beta.-glucuronate pUC-18 10 pMPX-8 melR Melibiose
pUC-18 11 pMPX-18 araC Arabinose pUC-18 12 pMPX-6 araC Arabinose
pUC-18 13
[1145]
15TABLE 14 OLIGONUCLEOTIDE PRIMER SEQUENCES FOR TABLE 13 CONSTRUCTS
SEQ ID NO.: Primer name 5' to 3' sequence 69 Rha-1
GCGAATTGAGATGACGCCACTGGC 70 Rha-2 CCTGCTGAATTTCATTAACGACCAG 71
Rha-1-HindIII CCTGCTGAATTTCATTAACGACCAG CACTGGC 72 Rha-2-PstI
CGCCGTAATCGCCGCTGCAGAATGTGATCCTGCTGAATTTC ATTAACGACCAG 73 Uid-1
CGCAGCGCTGTTCCTTTGCTCG 74 Uid-2 CCTCATTAAGATAATAATACTGG 75
Uid-1-HindIII GCCGCAAGCTTCGCAGCGCTGTTCCTTTGCTCG 76 Uid-2-PstI
CCAATGCATTGGTTCTGCAGGACTCCTCATTAAGATAATAA TACTGG 77 Mel-1
CGTCTTTAGCCGGGAACG 78 Mel-2 GCAGATCTCCTGGCTTGC 79 Mel-1-HindIII
GCCGCAAGCTTCGTCTTTAGCCGGGAAACG 80 Mel-2-SaII
CGGTCGACGCAGATCTCCTGGCTTGC 81 Ara-1 CAAGCCGTCAATTGTCTGATTCG 82
Ara-2 GGTGAATTCCTCCTGCTAGCCC 83 Ara-1-HindIII
GCGCCAAGCTTCAAGCCGTCAATTGTCTGATTCG 84 Ara-2-PstI
CTGCAGGGTGAATTCCTCCTGCTAGCCC 85 Ara-1-XhoI
GCTTAACTCGAGCTTAATAACAAGCCGTCAATTGTCTGATTC 86 Ara-2-SstI
GCTTAACCGCGGGCCAAGCTTGCATGCCTGCTCC
[1146] Oligonucleotides SEQ ID NOS.:69, 70, 71 and 72 were used to
amplify the rhaRS genes and their divergent control region from the
E. coli chromosome. Once amplified, this region was inserted into
pUC18 using HindIII and PstI to create SEQ ID NO.: 6.
[1147] Oligonucleotides SEQ ID NOS.:73, 74, 75 and 76 were used to
amplify the uidR control region, the uidR gene and the control
region for expression from the E. coli chromosome. Once amplified,
this region was inserted into pUC18 using HindIII and PstI to
create SEQ ID NO.: 10.
[1148] Oligonucleotides SEQ ID NOS.:77, 78, 79 and 80 were used to
amplify the melR gene and its divergent control region from the E.
coli chromosome. Once amplified, this region was inserted into
pUC18 using HindIII and SalI to create SEQ ID NO.: 11.
[1149] Oligonucleotides SEQ ID NOS.:81, 82, 83 and 84 were used to
amplify the araC gene and its divergent control region from the E.
coli chromosome. Once amplified, this region was inserted into
pUC18 using HindIII and PstI to create SEQ ID NO.: 12.
[1150] Oligonucleotides SEQ ID NOS.:81, 82, 85 and 86 were used to
amplify the araC gene and its divergent control region was PCR
amplified from pBAD-24. Once amplified, this region was inserted
into pEGFP (Clontech) using XhoI and SstI to create SEQ ID NO.:
13.
[1151] Except of pMPX-6, these expression constructs contain the
same multiple cloning site. Therefore, any protein of interested
may be inserted in each modular expression construct for simple
expression screening and optimization.
[1152] By way of non-limiting example, other proteins that may be
expressed are listed in Table 15.
16TABLE 15 OTHER EXPRESSED PROTEINS SEQ ID Protein Origin Construct
Purpose NO.: Edg3 Rat native GPCR 14 .beta.2AR Human native GPCR 15
TNFR-1a Human residues 29-455 Receptor 18 (human) TNFR-1b Human
residues 41- Receptor 17 (human) 455 TNF (human) Human native Gene
transfer 19 T-EGF Human chimera Gene transfer 20 T-Invasin Y.
pseudotuberculosis chimera Gene transfer 21
[1153]
17TABLE 16 OLIGONUCLEOTIDE PRIMER SEQUENCES FOR TABLE 15 SEQ ID
NO.: Primer name 5' to 3' sequence 87 Edg-1
GGCAACCACGCACGCGCAGGGCCACC 88 Edg-2 CAATGGTGATGGTGATGATGACCGG 89
Edg-1-SaII CGCGGTCGACATGGCAACCACGCACG- CGCAGGGCCACC 90 Edg-2-KpnI
GCGCCGGTACCTTATCAATGGTGATGGTGATGATGACCGG 91 .beta.2AR-1
GGGGCAACCCGGGAACGGCAGCGCC 92 .beta.2AR-2
GCAGTGAGTCATTTGTACTACAATTCCTCC 93 .beta.2AR-1-SaII
CGCGGTCGACATGGGGCAACCCGGGAACGGCAGCGCC 94 .beta.2AR-2-BamHI
GCGCCGGATCCTTATTATAGCAGTGAGTCATTTGTACTAC AATTCCTCC 95 TNFR(29)-1
GGACTGGTCCCTCACCTAGGGGACAGGG 96 TNFR(29)-2
CTGAGAAGACTGGGCGCGGGCGGGAGG 97 TNFR(29)-1-SaII
CGCGGGTCGACATGGGACTGGTCCCTCACCTAGGGGACA GGG 98 TNFR(29)-2-KpnI
GCGCCGGTACCTTATTACTGAGAAGACTGGGCGCGGGCG GGAGG 99 TNFR(41)-1
GATAGTGTGTGTCCCC 100 TNFR(41)-2 CTGAGAAGACTGGGCGC 101
TNFR(41)-1-NcoI GGGAGACCATGGATAGTGTGTGTCCCC 102 TNFR(41)-2-XbaI
GCCTCATCTAGATTACTGAGAAGACTGGGCGC 103 TNF-1
GAGCACTGAAAGCATGATCCGGGACG 104 TNF-2 CAGGGCAATGATCCCAAAGTAGA- CCTGC
105 TNF-1-EcoRI CCGCGGAATTCATGAGCACTGAAAGCATGATCCGGGACG 106
TNF-2-HindIII GGCGCAAGCTTATCACAGGGCAATGATCCCAAAGTAGAC CTGC 107
T-EGF-1 TCTGATAGCGGTCTTACTTCCCCTCGCAGTATTACTGCTC
AATAGTGACTCTGAATGTCCCCTGTCCCACGATGGGTACT GCCTCCATGATGGTGTGTGCATG-
TATATTG 108 T-EGF-2 AGGTCTCGGTACTGACATCGCTCCCCGATGTAGCCAACA
TGCACACACCATCATGGAGGCA 109 T-EGF-3 CCGCGGGTACCATGAACTTGGGGAATCGAC-
TGTTTATTCT CGGTACTGACATCGCTCCCCCG 110 T-EGF-4
GCGCCAAGCTTATTAGCGCAGTTCCCACCACTTCAGGTCT CGGTACTGACATCGCTCCCCG 111
Inv-1 TCATTCACATTGAGCGTCACCG 112 Inv-2 TTATATTGACAGCGCACAGAGCGG 113
Inv-1-ToxR-EcoRI GCAAGAATTCACCATGAACTTGGGGAATCGACTGTTTATT
CTGATAGCGGTCTTACTTCCCCT- CGCAGTATTACTGCTCT CATTCACATTGAGCGTCACCG
114 Inv-2-PstI CGCGGTTACGTAAGCAACTGCAGTTATATTGACAGCGCA CAGAGCGG
[1154] Oligonucleotides SEQ ID NOS.:87, 88, 89 and 90 were used to
amplify rat Edg3 from rat cDNA. Once amplified, this region was
inserted into SEQ ID NO.: 6 (pMPX-5) using SalI and KpnI ID NO.:
14.
[1155] Oligonucleotides SEQ ID NOS.:91, 92, 93 and 94 were used to
amplify human .beta.2 adrenergic receptor (.beta.2AR) from human
heart cDNA. Once amplified, this region was inserted into SEQ ID
NO.: 6 (pMPX-5)using SalI and BamHI to create SEQ ID NO.: 15.
[1156] Oligonucleotides SEQ ID NOS.:95, 96, 97 and 98 were used to
amplify human tumor necrosis factor receptor (TNFR residues 29-455)
from human Jurkat CL71 cDNA. Once amplified, this region was
inserted into SEQ ID NO.: 12 (pMPX-18) using SalI and KpnI to
create SEQ ID NO.:18.
[1157] Oligonucleotides SEQ ID NOS.:99, 100, 101 and 102 were used
to amplify human tumor necrosis factor receptor (TNFR residues
41-455) from human Jurkat CL71 cDNA. Once amplified, this region
was inserted into pBAD24 using NcoI and XbaI to create SEQ ID
NO.:17.
[1158] Oligonucleotides SEQ ID NOS.: 103, 104, 105 and 106 were
used to amplify human tumor necrosis factor (TNF) from human Jurkat
CL71 cDNA. Once amplified, this region was inserted into SEQ ID
NO.:13 (pMPX-6) using EcoRI and HindIII to create SEQ ID
NO.:19.
18TABLE 17 PROGRAM TO ANNEAL GRADIENT PCR WITH PFX POLYMERASE Temp
Time Step (.degree. C.) (min) 1 95 2.0 2 95 0.5 3 64 0.5 4 68 2.5 5
Goto 2, 2.times. 6 95 0.5 7 62 0.5 8 68 2.5 9 Goto 6, 4.times. 10
95 0.5 11 60 0.5 12 68 2.5 13 Goto 10, 6.times. 14 95 0.5 15 58 0.5
16 68 2.5 17 Goto 14, 24.times. 18 4 hold 19 end
[1159] Oligonucleotides SEQ ID NOS.: 107, 108, 109 and 110 were
mixed and PCR amplified using anneal gradient PCR (Table 17) to
form mature human epidermal growth factor (EGF) (residues 971-1023)
translationally fused to the transmembrane domain of toxR from
Vibrio cholerae. Once amplified, this region was inserted into SEQ
ID NO.: 13 (pMPX-6) using KpnI and HindIII to create SEQ ID
NO.:20.
[1160] Using PFX polymerase (Invitrogen) oligonucleotide SEQ ID
NO.:111, 112, 113 and 114 were used to amplify, invasin residues
490-986 (inv) from Yersinia pseudotuberculosis chromosomal DNA and
form a translational fusion between the transmembrane domain of
toxR from Vibrio cholerae. Once amplified, this region was inserted
into SEQ ID NO.:13 (pMPX-6) using EcoRI and PstI to create SEQ ID
NO.:21.
[1161] These proteins were proof-of-principle constructs used to
evaluate the minicell platform. For purposes of this initial
evaluation, all proteins except TNF, T-EGF and T-Invasin were
cloned into pMPX-5, with these later proteins cloned into pMPX-6
for gene transfer experiments.
[1162] Whether the approach for protein expression is co-expression
with minicell induction or expression following minicell and/or
protoplast isolation; the procedure to transform the expression
construct is the same. To accomplish this, protein constructs were
initially cloned into E. coli MG1655 and then into the minicell
producing strain of interest. Transformation events were selected
prior to minicell induction. For co-induction of protein and
minicells, see the protocol for phoA expression above. For
post-minicell and/or protoplast purification induction experiments,
following minicell purification and/or protoplast preparation and
purification, these cellular bodies were induced for protein
production in either LBD or MDT at a minicell or protoplast/volume
ratio of 1.times.10.sup.9 minicells or protoplasts/1 ml media.
Media was supplemented with the appropriate inducer concentration
(see Table 6). Protein induction is sensitive to a variety of
factors including, but not limited to aeration and temperature,
thus reaction volume to surface area ratio is important, as is the
method of shaking and temperature of induction. Therefore, each
protein must be treated as required to optimize expression. In
addition to expression parameters, protoplasted minicells are
sensitive to osmotic and mechanical forces. Therefore, protoplast
protein induction reactions must also contain 10% sucrose with
greater volume to surface area ratios than required for intact
minicells to achieve similar aeration at lower revolutions.
[1163] Using the T-PhoA as a non-limiting example, protein
expression was performed during and following minicell isolation.
To accomplish this task, t-phoA co-expressed with minicell
induction was compared to t-phoA expressed after minicell
isolation. In both cases, overnight minicell-producing parental
strains containing pMPX-5::t-phoA were subcultured into LBD
supplemented with the appropriate antibiotic. Cultures were grown
to OD.sub.600 0.1 and induced for minicell production alone or for
both minicell and protein production. Both cultures were harvested
at OD.sub.600 1.0 and minicells produced were harvested as
described above. Minicells to be induced for T-phoA production
following purification were induced by introducing 1.times.10.sup.9
purified minicells into a 15 ml culture tube containing 1 ml MDT
with 1 mM L-rhamnose. Minicell protein induction was allowed to
proceed for up to 14 hours and compared to protein production
obtained using the co-expression approach. For each approach,
minicells were fractionated and analyzed for membrane association,
total protein, and membrane association-dependent enzymatic
activity. These observations were compared to post-induction,
pre-isolation parental cell/minicell (PC/MC) mixtures from the
co-expressed reactions. The first observation was that
co-expression of minicell and protein induction was superior to
post-minicell purification induction (Table 18). However, although
the kinetics are slower for the post-minicell purification
induction protocol, the end result is equivalent.
19TABLE 18 COMPARATIVE EXPRESSION: CO-EXPRESSION VERSUS POST
MINICELL PURIFICATION INDUCTION Time of induction Purified minicell
induction .sup.a Co-expression induction .sup.a 1.0 8.0 -- 2.0 --
812.2 4.0 70.0 -- 14.0 445.0 -- .sup.a Nanogram expressed T-PhoA
per 1 .times. 10.sup.9 minicells.
[1164] Using the co-expression induction procedure, the amount of
membrane-associated T-PhoA was measured and compared for both
parental cells and minicells. Briefly, following co-expression
induction of T-PhoA and minicells, minicells were purified and
their membranes isolated. For membrane isolation, minicells
containing expressed T-PhoA were subjected to three rounds of
freeze-thaw lysis in the presence of 10 .mu.g/ml lysozyme.
Following freeze-thaw cycling, the reaction was subjected to
sonication. Sonicated material was centrifuged at 6,000 rpm in a
microcentrifuge for 5 min at room temperature. Supernatants were
transferred to a fresh 1.5 ml Eppendorf tube and centrifuged at
70,000 rpm using a TLA-100 rotor. Following centrifugation, the
pellet was resuspended in buffer and analyzed for total T-PhoA
protein (Table 19) and T-PhoA enzyme activity (Table 20).
20TABLE 19 MEMBRANE ASSOCIATED T-PHOA: PARENTAL CELLS VERSUS
MINICELLS Protein T-PhoA T-PhoA Protein T-PhoA T-PhoA membrane
membrane % membrane Cell type .sup.a total .sup.a total .sup.b %
total associated .sup.a associated .sup.b protein total Parental
cells 107.5 5.3 4.9 10.7 3.1 29.0 Minicells 4.6 0.8 17.5 1.0 0.5
50.0 Minicells EQ .sup.b 25.2 4.4 -- 5.5 2.7 -- .sup.a Total
protein as determined by BCA assay (Pierce) .sup.b Microgram
expressed T-PhoA per 1 .times. 10.sup.9 minicells as determined via
Western using an anti-PhoA antibody (Sigma) versus a PhoA standard
curve (BCA determined). .sup.c Equivalent membrane lipid to
parental cell
[1165]
21TABLE 20 PHOA ENZYMATIC ACTIVITY.sup.a (RELATIVE UNITS): PARENTAL
CELLS VERSUS MINICELLS. Cell type.sup.b Unlysed Lysed, total Lysed,
membrane Parent cell -- 358 240 Minicell 275 265 211 Minicell
EQ.sup.c 1,504 1,447 1,154 .sup.aActivity determined
colorimetrically using PNPP measuring optical density at 405 nm
.sup.bBased on 1 .times. 10.sup.9 parental cells or minicells per
reaction .sup.cEquivalent membrane lipid to parental cell
[1166] These results suggest that co-expression induction of T-PhoA
and minicells together results in minicells containing an
equivalent amount of T-PhoA produced in both parental cells and
minicells. However, the percent of T-PhoA compared to total protein
is 3.5.times. greater in minicells than in parental cells.
Furthermore, of the protein made, T-PhoA constitutes 50% of the
total membrane protein in minicells, whereas it is only 29% in
parental cells. It should be noted that the T-PhoA protein
associated with the membrane can be easily removed by treatment
with mild, non-ionic detergent suggesting that the T-PhoA present
in the membrane pellet is indeed associated with the membrane and
not an insoluble, co-sedimenting precipitate (data not shown).
Finally, PhoA is a periplasmic enzyme that requires export to the
periplasmic space for proper folding and disulfide bond formation.
Both of which are required for enzymatic activity. In the time
course of this experiment, expression of .DELTA.PhoA lacking a
leader sequence does not demonstrate enzymatic activity.
Furthermore, there is no difference between unlysed and lysed
minicells containing expressed T-PhoA (Table 20) also demonstrating
that the PhoA enzyme domain of the T-PhoA chimera must be present
in the periplasmic space. Therefore, the T-PhoA construct must
membrane associate and the PhoA domain must orient into the
periplasmic space for enzymatic activity. Thus, when comparing
equivalent amounts of membrane lipid between parental cells and
minicells in Table 20, membrane association-dependent T-PhoA
activity is almost 5.times. greater than in parental cells. Taking
into account the data in Table 19 where 50% of T-PhoA is in the
membrane compared to 29% in parental cells, the difference in
T-PhoA membrane association is not sufficient to explain the almost
5.times. increase in minicell activity. These observations suggest
that minicells contain a capacity to support more expressed
membrane protein than parental cells and that the protein that
associates with the membrane is more active. This activity may be
simply result from minicells allowing greater efficiency of folding
and disulfide bond formation for this particular protein. However,
do to the fact that minicells do not contain chromosome, it is also
possible that the overexpression of this protein is readily finding
membrane-binding sites in the absence of chromosomally produced
competitors present in parental cells. Furthermore, overexpression
of proteins often leads to increased protease expression. Because
minicells do not contain chromosome, these otherwise degraded
surplus T-PhoA is allowed the continued opportunity to insert and
properly fold in the membrane, an attribute that could lend favor
to overexpression of more complex membrane proteins.
Example 18
Exemplary Methods to Induce and Study Complex Membrane Proteins
[1167] Expression of non-native (exogenous) complex membrane
proteins in bacterial systems can be difficult. Using the minicell
system, we are able to eliminate toxicity issues. However, issues
still remain with proper translation, compartmentalization at the
membrane, insertion in the membrane and proper folding for native
activity. To account for these potential problems we have
constructed a modular chimeric system that incorporates leader
sequences and chaperone-recognized soluble domains that are native
to our bacterial minicell system. In addition, we created modular
constructs that overexpress the native chaperones groESL and
trigger factor (tig). Finally, we have constructed
minicell-producing strains that contain mutations that effect
protein export and disulfide bond formation. For non-limiting
examples of these constructs see Table 21.
22TABLE 21 NON-LIMITING TOOLS FOR EXOGENOUS COMPLEX PROTEIN
SYNTHESIS AND FUNCTION Residues of Tool Reference sequence Purpose
SEQ ID NO pMPX-5::phoA leader -- 1-48 Membrane targeting 22
pMPX-5::phoA leader -- 1-494 Membrane targeting 23 pMPX-5::malE
leader 1 1-28 Membrane targeting 24 pMPX-5::malE leader 1 1-370
Membrane targeting 25 pMPX-17 (groESL, tig) -- -- Chaperone 26
pMPX-5::trxA::FLAG 2 2-109 .sup.a.sup. Solubility 27 .sup.a
Residues do not include FLAG sequence.
References to Table 21
[1168] 1. Grisshammer, R., et al. 1993. Expression of a rat
neurotensin receptor in Escherichia coli. Biochem. J.
295:571-576.
[1169] 2. Tucker, J., and R. Grisshammer. 1996. Purification of a
rat neurotensin receptor expressed in Escherichia coli. Biochem. J.
317:891-899.
23TABLE 22 OLIGONUCLEOTIDE PRIMER SEQUENCES FOR TABLE 21 CONSTRUCTS
SEQ ID NO.: Primer name 5' to 3' sequence 115 PhoA lead-1
GTCACGGCCGAGACTTATAGTCGC 116 PhoA lead-2 GGTGTCCGGGCTTTTGTCACAGG
117 PhoA lead-1-PstI CGCGGCTGCAGATGTCACGGCCGAGACTTATAGTCGC 118 PhoA
lead-2-XbaI CGCGGTCTAGATTCTGGTGTCCGGGCTTTTGTCACAGG 119 PhoA
complete CAGCCCCAGAGCGGCTTTCATGG 120 PhoA complete-2-XbaI
CGCGGTCTAGATTTCAGCCCCAGAGCGGCTTTCATG G 121 MalE lead-1
CGCGGCTGCAGATGAAAATAAAAACAGGTGCACGC
ATCCTCGCATTATCCGCATTAACGACGATGATGTTTT CCGCCTCGGCTCTCGCCAAAATCTCT-
AGACGCGG 122 MalE lead-2 CCGCGTCTAGAGATTTTGGCGAGAGCCGAGGCG- GAA
AACATCATCGTCGTTAATGCGGATAATGCGAGGATG
CGTGCACCTGTTTTTATTTTCATCTGCAGCCGCG 123 MalE-1
GGTGCACGCATCCTCGCATTATCCGC 124 MalE-2 CGGCATACCAGAAAGCGGACATCTGC
125 MalE-1-PstI CGCGGCTGCAGATGAAAATAAAAACAGGTGCACGC
ATCCTCGCATTATCCGC 126 MalE-2-XbaI
CGCGGTCTAGAACGCACGGCATACCAGAAAGCGGA CATCTGC 127 Tig-1
CGCGACAGCGCGCAATAACCGTTCTCG 128 Tig-2 GCTGGTTCATCAGCTCGTTGAAAGTGG
129 Tig-1-NarI GCGCCGGCGCCATACGCGACAGCGCGCAATAACCGT TCTCG 130
Tig-2-XbaI GGCGCTCTAGATTATTATTACGCCTGCTGGTTCATCA GCTCGTTGAAAGTGG
131 Gro-1 GGTAGCACAATCAGATTCGCTTATGACGG 132 Gro-2
GCCGCCCATGCCACCCATGCCGCCC 133 Gro-1-XbaI
GCGTCTAGAGGTAGCACAATCAGATTCGCTTATGACGG 134 Gro-2-HindIII
GGCGCAAGCTTATTATTACATCATGCCGCCCATGCC ACCCATGCCGCCC 135 TrxA-1
GCGATAAAATTATTCACCTGACTGACG 136 TrxA-2 GCGTCGAGGAACTCTTTCAACTGACC
137 TrxA-1-Fxa-PstI CGCGGCTGCAGATGATCGAAGCCCGCTCTAGACTCG
AGAGCGATAAAATTATTCACCTGACTG- ACG 138 TrxA-2-FLAG-BamHI
CCGCGGGATCCTTATTAATCATCATGATCTTT- ATAAT
CGCCATCATGATCTTTATAATCCTCGAGCGCCAGGTT
AGCGTCGAGGAACTCTTTCAACTGACC
[1170] Oligonucleotides SEQ ID NOS.:115, 116, 117 and 118 were used
to amplify the phoA leader (residues 1-49) from E. coli chromosomal
DNA. Once amplified, this region was inserted into SEQ ID NO.:6
(pMPX-5) using PstI and XbaI to create SEQ ID NO.:22.
[1171] Oligonucleotides SEQ ID NOS.:115, 117, 119 and 120 were used
to amplify the complete phoA gene from E. coli chromosomal DNA.
Once amplified, this region was inserted into SEQ ID NO.: 6
(pMPX-5) using PstI and XbaI to create SEQ ID NO.23.
[1172] Oligonucleotides SEQ ID NOS.:121 and 122 were used to
construct the malE leader (residues 1-28) sequence. Once annealed,
this construct was inserted into SEQ ID NO.: 6 (pMPX-5) using PstI
and XbaI to create SEQ ID NO.:24.
[1173] Oligonucleotides SEQ ID NOS.:123, 124, 125 and 126 were used
to amplify the malE expanded leader (residues 1-370) from E. coli
chromosomal DNA. Once amplified, this region was inserted into SEQ
ID NO.: 6 (pMPX-5) using PstI and XbaI to create SEQ ID NO.:25.
[1174] Oligonucleotides SEQ ID NOS.:127, 128, 129 and 130 were used
to amplify the tig control and gene region from E. coli chromosomal
DNA. Once amplified, this region was ligated to the groESL
amplified region below using XbaI prior to insertion into SEQ ID
NO.: 6 (pMPX-5) using NarI (from the tig region) and HindIII (from
the groESL region) to create SEQ ID NO.:26.
[1175] Oligonucleotides SEQ ID NOS.:131, 132, 133 and 134 were used
to amplify the groESL control and gene region from E. coli
chromosomal DNA. Once amplified, this region was ligated to the tig
amplified region above using XbaI prior to insertion into SEQ ID
NO.: 6 (pMPX-5) using NarI (from the tig region) and HindIII (from
the groESL region) to create SEQ ID NO.:26.
[1176] Oligonucleotides SEQ ID NOS.:135, 136, 137 and 138 were used
to amplify trxA (residues 2-109) from E. coli chromosomal DNA and
insert FLAG and Factor Xa sequences. Once amplified, this region
was inserted into SEQ ID NO.: 6 (pMPX-5) using PstI and BamHI to
create SEQ ID NO.:27.
[1177] By way of non-limiting example, the pMPX-5::phoA leader
(residues 1-48), pMPX-5::phoA leader (residues 1-494), pMPX-5::malE
leader (residues 1-28), and pMPX-5::malE leader (residues 1-370)
constructs are designed to direct expressed exogenous membrane
proteins to the minicell cytoplasmic membrane. In addition to these
constructs, By way of non-limiting example, mutations in E. coli
genes secA and secY, specifically mutation prlA4 (Strader, J., et
al. 1986. Kinetic analysis of lamB mutants suggests the signal
sequence plays multiple roles in protein export. J. Biol. Chem.
261:15075-15080); permit promiscuous targeting to the membrane.
These mutations, like the above constructs are integrated into the
minicell expression system. To complement these mutations, the
chaperone complex groESL and trigger factor have also been
incorporated into the expression system. By way of non-limiting
example, pMPX-5::trxA::FLAG will be used to create a
carboxy-terminal fusion to the protein of interest to increase the
membrane insertion efficiency of the membrane protein of interest
(Tucker, J., and R. Grisshammer. 1996. Purification of a rat
neurotensin receptor expressed in Escherichia coli. Biochem. J.
317:891-899). Also By way of non-limiting example,
pMPX-5::FLAG::toxR and pMPX-5::FLAG::.lambda.cI constructs will be
prepared to create a carboxy-terminal fusion to the protein of
interest for use in a reporter-based assay for protein-protein
interactions. By way of non-limiting example, the protein of
interest for this system is a GPCR. Also By way of non-limiting
example, this GPCR may be the neurotensin receptor from rat
(Grisshammer, R., et al. 1993. Expression of a rat neurotensin
receptor in Escherichia coli. Biochem. J. 295:571-576.), or the
.beta.2 adrenergic receptor from humans (Freissmuth, M., et al.
1991. Expression of two .beta.-adrenergic receptors in Escherichia
coli: functional interaction with two forms of the stimulatory G
protein. Proc. Natl. Acad. Sci. 88:8548-8552). Insertion of a GPCR
into one of these reporter constructs creates a carboxy-terminal
fusion between the GPCR of interest and the DNA-binding regulatory
domain of the ToxR positive activator, the .lambda.cI repressor, or
the AraC positive activator. To complete this reporter system, By
way of non-limiting example pMPX-5::(X)::toxR or
pMPX-5::(X)::.lambda.cI will be used to create a carboxy-terminal
fusion to the protein of interest for use in a reporter-based assay
for protein-protein interactions, where (X) may be any protein or
molecule involved in an intermolecular or intramolecular
interaction. By way of non-limiting example, this molecule of
interest may be a G-protein. This G-protein may be the
G.alpha..sub.i1-protein from rat (Grisshammer, R., and E. Hermans.
2001. Functional coupling with G.alpha.q and G.alpha.i1 protein
subunits promotes high-affinity agonist binding to the neurotensin
receptor NTS-1 expressed in Escherichia coli. FEBS Lett.
493:101-105), or the G.sub.s.sub..sub..alpha.-protein from human
(Freissmuth, M., et al. 1991. Expression of two .beta.-adrenergic
receptors in Escherichia coli: functional interaction with two
forms of the stimulatory G protein. Proc. Natl. Acad. Sci.
88:8548-8552). Like the GPCR, insertion of a G-protein into one of
these reporter constructs creates a carboxy-terminal fusion between
the G-protein of interest and the DNA-binding regulatory domain of
the ToxR positive activator, the .lambda.cI repressor, or other
regulatory protein. Finally, these plasmid constructs contain the
DNA-binding domain of each regulator; the ctx regulatory region
from Vibrio cholerae (Russ, W. P., and D. M. Engelman. 1999.
TOXCAT: a measure of transmembrane helix association in a
biological membrane. 96:863-868), or the P.sub.R1O.sub.R1 region of
bacteriophage lambda (Hu, J. C., et al. 1990. Sequence requirements
for coiled-coils: analysis with lambda repressor-GCN4 leucine
zipper fusions. Science. 250:1400-1403), respectively. By way of
non-limiting example, each binding domain is coupled to a reporter
sequence encoding luciferase (Dunlap, P. V., and E. P. Greenberg.
1988. Control of Vibrio fischeri lux gene transcription by a cyclic
AMP receptor protein-luxR protein regulatory circuit. J. Bacteriol.
170:4040-4046), green fluorescent protein (GFP) (Yang, T. T., et
al. 1996. Dual color microscopic imagery of cells expressing the
green fluorescent protein and a red-shifted variant. Gene.
173:19-23; Matthysse, A. G., et al. 1996. Construction of GFP
vectors for use in gram-negative bacteria other than Escherichia
coli. FEMS Microbiol. Lett. 145:87-94), or other reporter.
Co-expression of these GPCR and G-protein chimeras will create a
system measuring the interaction between a GPCR and G-protein
within an intact minicell. This system is designed to be used as a
positive or negative read-out assay and may be used to detect loss
or gain of GPCR function. Although the GPCR-G-protein interaction
is provided as an example, this modular system may be employed with
any soluble or membrane protein system measuring protein-protein or
other intermolecular interaction.
Example 19
Exemplary Methods for Gene Transfer Using Minicells or Minicell
Protoplast
[1178] Included in the design of the invention is the use of
minicells to transfer genetic information to a recipient cell. By
way of non-limiting example, this gene transfer may occur between a
minicell and a mammalian cell in vitro, or in vivo, and this gene
transfer may occur through cell-specific interactions, through
general interactions, or a combination of each. To accomplish this
task three basic constructs were created. Each of these constructs
is created in pMPX-6 which contains a CMV promotor controlling the
synthesis of GFP. The plasmid pMPX-6 was constructed by cloning the
araC through the multiple cloning site of pBAD24 into pEGFP
(Clontech). This construct provided a bacterial regulator as well
as a method to monitor the success of gene transfer using GFP
expression form the CMV promotor. In design, the protein expressed
using the bacterial promotor will drive the cell-cell interaction,
while the successful transfer of DNA from the minicell to the
recipient cell will initiate the production of GFP. By way of
non-limiting example, proteins that will drive the cell-cell
interaction may be the invasin protein from Yersinia
pseudotuberculosis, which stimulates .beta.1 integrin-dependent
endocytic events. To properly display the invasin protein on the
surface of minicells, the domain of invasin that stimulates these
events (residues 490-986) (Dersch, P., and R. R. Isberg. 1999. A
region of the Yersinia pseudotuberculosis invasin protein enhances
integrin-mediated uptake into mammalian cells and promotes
self-association. EMBO J. 18:1199-1213) was fused to the
transmembrane domain of ToxR. Expression of this construct from
pMPX-6 will display T-Inv on the surface of the minicell and
stimulate endocytosis with any cell displaying a .beta.1 integrin.
Thus, T-Inv display will provide a general mechanism of gene
transfer from minicells. To provide specificity, By way of
non-limiting example, the ligand portion of epidermal growth factor
(EGF) may be fused to the transmembrane domain of ToxR, thus
creating a protein that will interact with cells displaying the EGF
receptor (EGFR). Likewise, tumor nucrosis factor (TNF) may also
serve this purpose by stimulating cell-cell interactions between
minicells displaying TNF and cells displaying TNF receptor (TNFR).
Although EGF-EGFR and TNF-TNFR interactions may stimulate cell-cell
fusion between minicells and recipient cells, or minicell uptake,
this alone may not be sufficient to efficiently transfer genetic
information from minicells. Therefore, a genetic approach to
increasing the cell-cell genetic transfer may be the development of
a genetic switch that senses the specificity interaction, e.g.
EGF-EGFR interaction, and turns on the production of a second gene
product, e.g. invasin, that stimulates the endocytic event. By way
of non-limiting example, this genetic switch may be similar to the
GPCR-G-protein interaction reporter system above, in that an
extracellular event stimulates the dimerization of a
transcriptional active regulator, thus turning on the production of
invasin or invasin-like protein. In either approach, the display
system to stimulate transfer of genetic information from minicells
to recipient cells may also be applicable to the transfer of
substances other than genetic information, e.g. pre-synthesized
therapeutic drugs.
[1179] To test this targeting methodology, different pMPX-6
constructs containing each of these general or specific cell-cell
interaction proteins will be transformed into a minicell producing
strain and either by co-expression induction of minicells, by
post-minicell purification induction, or by post-protoplasting
induction, minicells displaying the targeting protein of interest
will be produced. When using the co-expression induction and
post-minicell purification induction of the targeting protein
approaches, it is necessary to protoplast the purified minicells
after protein induction. Once the targeting protein has been
displayed on the surface of a minicell protoplast, these
protoplasts are ready to be exposed to target cells. For
preliminary experiments these interactions will be monitored using
cell culture of Cos cells in comparison to lipofectamine
(Invitrogen), electroporation, and other transfection techniques.
Initial experiments will expose protoplasts displaying T-Inv to Cos
cells and compare the transfection efficiency to protoplast
containing pMPX-6::t-inv in the absence of t-inv expression, naked
pMPX-6::t-inv alone, and naked pMPX-6::t-inv with lipofectamine.
Each of these events will be monitored using fluorescent microscopy
and/or flow cytometry. From these results the specific targeting
apparatus proteins will be tested. Using A-431 (display EGFR) and
K-562 (no EGFR) cell lines, the pMPX-6::t-egf constructs will be
tested. Using the same approaches as for the t-inv study, the level
of transfection between A-431 and K-562 cell lines will be measured
and compared to those achieved using lipofectamine. Similarly, the
ability of TNF to stimulate gene transfer will be studied using
L-929 cells. In all cases, the ability of these general and
specific targeting protein constructs will be compared to standard
transfection techniques. Upon positive results, these methodologies
will be tested on difficult to transfect cell lines, e.g. adult
cardiomyocytes. The basis of these results will create a foundation
for which applications into in vivo gene transfer may occur.
Example 20
Additional and Optimized Methods for Generic Expression
[1180] Expression in minicells may occur following purification of
minicells and/or minicell protoplasts from parental cells and LPS
constituents, respectively. However, for some applications it is
preferred to co-express proteins of interest with minicell
induction. For these approaches, one may use the protocol described
in Example 13 for expression of the phoA constructs. Either of
these approaches may be accomplished using one or more of the
following expression constructs (Table 23) and/or optimized
expression constructs (Table 25).
[1181] Expression plasmid pCGV1 contains a temperature sensitive
lambda cI repressor (cI857) and both lambda PR and PL promoters
(Guzman, C. A., et al. 1994. A novel Escherichia coli
expression-export vector containing alkaline phosphatase as an
insertional inactivation screening system. Gene. 148:171-172) with
an atpE initiation region (Schauder, B., et al. 1987. Inducible
expression vectors incorporating the Escherichia coli atpE
translational initiation region. Gene. 52:279-283). Included in the
design of the invention is the modification of this expression
vector to best align the required Shine-Delgarno ribosomal binding
site with cloning sites. In addition, the pCGVI expression vector
was modified to incorporate a stem-loop structure at the 3-prime
end of the transcript in order to provide a strong transcriptional
stop sequence (Table 23).
[1182] Expression plasmid pCL478 contains a temperature sensitive
lambda cI repressor (cI857) and both lambda PR and PL promoters
(Love, C. A., et al. 1996. Stable high-copy bacteriophage promoter
vectors for overproduction of proteins in Escherichia coli. Gene.
176:49-53). Included in the design of the invention is the
modification of this expression vector to best align the required
Shine-Delgarno ribosomal binding site with cloning sites. In
addition, the pCL478 expression vector was modified to incorporate
a stem-loop structure at the 3-prime end of the transcript in order
to provide a strong transcriptional stop sequence (Table 23).
24TABLE 23 LAMBDA CI857 EXPRESSION VECTOR MODIFICATIONS New Parent
Region Plasmid plasmid removed Region added .sup.a SEQ ID NO
pMPX-84 pCGV1 NdeI - BamHI NdeI, SD - PstI, XbaI, KpnI, Stem-loop,
BamHI 139 pMPX-85 pCGV1 NdeI - BamHI NdeI, SD - SalI, XbaI, KpnI,
Stem-loop, BamHI 140 pMPX-86 pCL478 BamHI - XhoI BamHI, SD - PstI,
XbaI, KpnI, Stem-loop, XhoI 141 pMPX-87 pCL478 BamHI - XhoI BamHI,
SD - SalI, XbaI, KpnI, Stem-loop, XhoI 142 .sup.a "SD" refers to a
Shine-Delgarno ribosome-binding sequence; "Stem-loop" refers to a
stem-loop structure that functions as a transcriptional stop
site.
[1183]
25TABLE 24 OLIGONUCLEOTIDE PRIMER SEQUENCES FOR TABLE 23 SEQ ID NO
Primer name 5' to 3' sequence 143 CGV1-1-SaII
TATGTAAGGAGGTTGTCGACCGGCTCAGTCTAGAGGTACCCGCCCTCA TCCGAAAGGGCGTATTG
144 CGV1-2-SaII GATCCAATACGCCCTTTCGGATGAGGGCGGGTACCTCTAGACTGAGCC
GGTCGACAACCTCCTTACA 145 CCV1-1-Pstl
TATGTAAGGAGGTTCTGCAGCGGCTCAGTCTAGAGGTACCCGCCCTCA TCCGAAAGGGCGTATTG
146 CCV1-2-PstI GATCCAATACGCCCTTTCGGATG- AGGGCGGGTACCTCTAGACTGAGCC
GCTGCAGAACCTCCTTACA 147 CL478-1-SaII
GATCCTAAGGAGGTTGTCGACCGGCTCAGTCTAGAGGTACCCGCCCTC ATCCGAAAGGGCGTATTC
148 CL478-2-SaII TCGAGAATACGCCCTTTCGGATGAGGGCGGGTACCTCTAGACTGAGCC
GGTCGACAACCTCCTTAG 149 CL478-1-PstI
GATCCTAAGGAGGTTCTGCAGCGGCTCAGTCTAGAGGTACCCGCCCTC ATCCGAAAGGGCGTATTC
150 CL478-2-PstI TCGAGAATACGCCCTTTCGGATGAGGGCGGGTACCTCTAGACTGAGCC
GCTGCAGAACCTCCTTAG
[1184] Oligonucleoides SEQ ID NOS.: 143 and 144 were annealed to
each other to generate a DNA molecule with a 5' overhang at both
ends. The overhangs are designed so that the DNA can be directly
cloned into pCGVI cut with NdeI (5' overhang is TA) and BamHI (5'
overhang is GATC). Insertion of the annealed DNA into pCGVI creates
SEQ ID NO.: 139, pMPX-84.
[1185] Oligonucleoides SEQ ID NOS.: 145 and 146 were annealed to
each other to generate a DNA molecule with a 5' overhang at both
ends. The overhangs are designed so that the DNA can be directly
cloned into pCGVI cut with NdeI (5' overhang is TA) and BamHI (5'
overhang is GATC). Insertion of the annealed DNA into pCGVI creates
SEQ ID NO.: 140, pMPX-85.
[1186] Oligonucleoides SEQ ID NOS.: 147 and 148 were annealed to
each other to generate a DNA molecule with a 5' overhang at both
ends. The overhangs are designed so that the DNA can be directly
cloned into pCL478 cut with BamHI (5' overlap is GATC) and XhoI
(overhang is TCGA). Insertion of the annealed DNA into pCL578 cut
with BamHI and XhoI creates SEQ ID NO.: 141, pMPX-86.
[1187] Oligonucleoides SEQ ID NOS.: 149 and 150 were annealed to
were annealed to each other to generate a DNA molecule with a 5'
overhang at both ends. The overhangs are designed so that the DNA
can be directly cloned into pCL578 cut with BamHI (5' overlap is
GATC) and XhoI (overhang is TCGA). Insertion of the annealed DNA
into pCL478 cut with BamHI and XhoI creates SEQ ID NO.: 142,
pMPX-87.
[1188] The optimized expression constructs in Table 25 were created
from SEQ ID NOS.: 6, 11, and 12 (see Table 13). Modifications were
made to optimize the alignment of the SalI or PstI cloning sites
with the Shine-Delgarno ribosome-binding site. In addition,
stem-loop transcriptional termination sequences were added on the
3' end of the cloning region.
26TABLE 25 EXPRESSION CONSTRUCTS Plasmid Regulatory element(s)
inducer Plasmid SEQ ID NO.: pMPX-67 RhaRS Rhamnose PUC-18 151
pMPX-72 RhaRS Rhamnose PUC-18 152 pMPX-66 AraC Arabinose PUC-18 153
pMPX-71 AraC Arabinose PUC-18 154 pMPX-68 MelR Melibiose PUC-18
155
[1189]
27TABLE 26 OLIGONUCLEOTIDE PRIMER SEQUENCES FOR TABLE 25 CONSTRUCTS
SEQ ID NO.: Primer name 5' to 3' sequence 69 Rha-1
GCGAATTGAGATGACGCCACTGGC 156 Rha-SD GCGAATTGAGATGACGCCACTGGC 71
Rha-1-HindIII CGGCGAAGCTTAATTAATTAATCTTTCTGCGAATTGAGATGACGC CACTGGC
157 Rha-SD SaII CCGCGGGTACCAATACGCCCTTTCGGATGAGGGCGCGGG KpnI
ATCCTCTAGAGTCGACGTCGACAACCTCCTGAATTTCATTA CGACC 158 Rha-SD KpnI
CCGCGGGTACCAATACGCCCTTTCGGATGAGGGCGCGGGG KpnI
ATCCTCTAGAGTCGACCTGCAGAACCTCCTGAATTTCATTA CGACC 81 Ara-1
CAAGCCGTCAATTGTCTGATTCG 159 Ara-SD
CTGCAGGGCCTCCTGCTAGCCCAAAAAAACGGGTATGG 83 Ara-1-HindIII
CCGCGGGTACCAATACGCCCTTTCGGATGAGGGCGCGGG 160 Ara-SD SaII
ATCCTCTAGAGTCGACGTCGACGGCCTCCTGCTAGCCCAAA KpnI
ATCCTCTAGAGTCGACGTCGACGGCCTCCTGCTAGCCCAAA AAAACGGGTATGG 161 Ara-SD
PstI CCGCGGGTACCAATACGCCCTTTCGGATGAGGGCGCGGGG KpnI
ATCCTCTAGAGTCGACCTGCAGGGCCTCCTGCTAGCCCAAA AAAACGGGTATGG 77 Mel-1
CGTCTTTAGCCGGGAAACG 162 Mel-SD CCTCCTGGCTTGCTTGAATACTTCATCATGG 79
Mel-1-HindIII GCCGCAAGCTTCGTCTTTAGCCGGGAACG 163 Mel-SD-SaII
CCGCGGGTACCAATACGCCCTTTCGGATGAGGGCGCGGGG KpnI
ATCCTCTAGAGTCGACCCCCTCCTGGCTTGCTTGAATAACT TCATCATGGC
[1190] Oligonucleotides SEQ ID NOS.: 69, 156, 72, and 157 were used
to amplify the rhaRS genes and their divergent control region from
the E. coli chromosome and insertion of an optimized
SalI-Shine-Delgarno ribosome-binding alignment and a stem-loop
transcriptional termination sequence. Once amplified, this region
was inserted into pUC18 using HindIII and KpnI to create pMPX67,
SEQ ID NO.: 151.
[1191] Oligonucleotides SEQ ID NOS.: 69, 156, 72, and 158 were used
to amplify the rhaRS genes and their divergent control region from
the E. coli chromosome and insertion of an optimized
PstI-Shine-Delgarno ribosome-binding alignment and a stem-loop
transcriptional termination sequence. Once amplified, this region
was inserted into pUC18 using HindIII and KpnI to create, pMPX-72,
SEQ ID NO.: 152.
[1192] Oligonucleotides SEQ ID NOS.: 81, 159, 81, 160 were used to
amplify the araC genes and their divergent control region from the
E. coli chromosome and insertion of an optimized
SalI-Shine-Delgarno ribosome-binding alignment and a stem-loop
transcriptional termination sequence. Once amplified, this region
was inserted into pUC18 using HindIII and KpnI to create, pMPX-66,
SEQ ID NO.: 153.
[1193] Oligonucleotides SEQ ID NOS.: 81, 159, 81, 161 were used to
amplify the araC genes and their divergent control region from the
E. coli chromosome and insertion of an optimized
PstI-Shine-Delgarno ribosome-binding alignment and a stem-loop
transcriptional termination sequence. Once amplified, this region
was inserted into pUC18 using HindIII and KpnI to createm pMPX-71,
SEQ ID NO.: 154.
[1194] Oligonucleotides SEQ ID NOS.: 77, 162, 79, 163 were used to
amplify the melR genes and their divergent control region from the
E. coli chromosome and insertion of an optimized
Sall-Shine-Delgarno ribosome-binding alignment and a stem-loop
transcriptional termination sequence. Once amplified, this region
was inserted into pUC18 using HindIII and KpnI to create, pMPX-68,
SEQ ID NO.: 155.
Example 21
Optimization of Rat Neurotensin Receptor (NTR) Expression
[1195] Expression of specific GPCR proteins in minicells may
require chimeric domain fusions to stabilize the expressed protein
and/or direct the synthesized protein to the membrane. The NTR
protein from rat was cloned into several chimeric combinations to
assist in NTR expression and membrane association (Grisshammer, R.,
et al. 1993. Expression of a rat neurotensin receptor in
Escherichia coli. Biochem. J. 295:571-576; Tucker, J., and
Grisshammer, R. 1996. Purification of a rat neutrotensin receptor
expressed in Escherichia coli. Biochem. J. 317:891-899). Methods
for construction are shown the Tables below.
28TABLE 27 NEUROTENSIN RECEPTOR EXPRESSION FACILITATING CONSTRUCTS
Protein .sup.a Construct .sup.b SEQ ID NO MalE(L) SalI-MalE
(1-370)-Factor Xa-NTR homology 164 NTR Factor Xa-NTR
(43-424)-NotI-FLAG-KpnI 165 MalE(L)-NTR SalI-MalE(1-370)-Factor
Xa-NTR(43-424)-NotI-FLAG-KpnI 166 MalE(S)-NTR
SalI-MalE(1-28)-Factor Xa-NTR(43-424)-NotI-FLAG-KpnI 167 TrxA
NotI-TrxA(2-109)-NotI 168 MalE(L)-NTR-TrxA SalI-MalE(1-370)-Factor
Xa-NTR(43-424)-NotI-TrxA(2-109)- 169 FLAG-KpnI MalE(S)-NTR-TrxA
SalI-MalE(1-28)-Factor Xa-NTR(43-424)-NotI-TrxA(2-109)-FLAG- 170
KpnI .sup.a (L) refers to MalE residues 1-370, and (S) refers to
MalE residues 1-28. .sup.b All mature constructs were cloned into
SalI and KpnI sites of SEQ ID NOS.: 140, 142, 151 and 153.
[1196]
29TABLE 28 OLIGONUCLEOTIDE PRIMER SEQUENCES FOR TABLE 27 SEQ ID
NO.: Primer name 5' to 3' sequence 171 MalE-1
GGTGCACGCATCCTCGCATFATCCGC 172 MaIE-2
CGCACGGCATACCAGAAAGCGGACATCTGCG 173 MalE-1-SaII
CCGCGGTCGACATGAAAATAAAAACAGGTGCACGCATCCTCGC 174 MalE-2-XaNTR
GCCGTGTCGGATTCCGAGGTGCGGCCTTCGATACGCACGGCAT ACCAAGAAAGCGGGATGTTCGGC
175 NTR-1 CCTCGGAATCCGACACGGCAGGG- C 176 NTR-2
GTACAGGGTCTCCCGGGTGGCGCTGG 177 NTR-1-Xa
CCGCGATCGAAGGCCGCACCTCGGAATCCGACACGGCAGGGCC 178 NTR-2-FIag
GGCGCGGTACCTTTGTCATCGTCATCTTTATAATCTGCGGCCGC
GTACAGGGTCTCCCGGGTGGCGCTGGTGG 179 NTR-2-Stop KpnI
GCGGCGGTACCTTATTATTTGTCATCGTCATCTTTATAATCTGC GGCCGCG 180 NTR-1-Xa
Lead CCGCATTAACGACGATGATGTFTTCCGCCTCGGCTCTCGCCAAA
ATCATCGAAGGCCGCACCTCGGAATCCGACACGGC 181 NTR-2-Lead2 SaII
CCGCGGTCGACATGAAAATAAAAACAGGTGCACGCATCCTCGC
ATTATCCGCATTAACGACGATGATGTTTTCCGCCTCGGC 182 TrxA-1
CCGCGAGCGATAAAATTATTCACCTGACTGACG 183 TrxA-2
GCCCGCCAGGTTAGCGTCGAGGAACTCTTTCAACTGACC 184 TrxA-1-NotI
GCGGCCGCAAGCGATAAAATTATTCACCTGACTGACG 185 TrxA-2-NotI
GGCGCTGCGGCCGCATCATCATGATCTTTATAATCGCC
[1197] Oligonucleotides SEQ ID NOS.: 171, 172, 173 and 174 were
used to amplify malE residues 1-370 from the E. coli chromosome to
create SEQ ID NO.: 164. Using overlap PCR with the extended NTR
homology, a chimeric translational fusion was made between MalE
(1-370) and NTR residues 43-424 (SEQ ID NO.: 165) to create a SEQ
ID NO.: 166. SEQ ID NO.: 166 was cloned into plasmids pMPX-85,
pMPX-87, pMPX-66 and pMPX-67 (respectively, SEQ ID NOS.: 140, 142,
151 and 153) using SalI and KpnI.
[1198] Three-step PCR with oligonucleotides, SEQ ID NOS.: 175 and
176 as primers was used to amplify NTR residues 43-424 from rat
brain cDNA. SEQ ID NOS.: 177 and 178 were then used with the NTR
(43-424) template to add factor Xa and FLAG sequence. Finally, SEQ
ID NOS.: 177 and 179 were used to add a KpnI site to create SEQ ID
NO.: 165. Using overlap PCR with malE(1-370) containing extended
NTR homology, a chimeric translational fusion was made between NTR
(43-424) and MalE (1-370) (SEQ ID NO.: 164) to create a SEQ ID NO.:
166. SEQ ID NO.: 166 was cloned into SEQ ID NOS.: 140, 142, 151 and
153 using SalI and KpnI.
[1199] Using three-step PCR oligonucleotides SEQ ID NOS.: 175 and
176 were first used to amplify NTR residues 43-424 from rat brain
cDNA. SEQ ID NOS.: 178 and 180 were then used with the NTR (43-424)
template to add factor Xa and FLAG sequence. Finally, SEQ ID NOS.:
179 and 181 were used to add KpnI to create SEQ ID NO.: 167. SEQ ID
NO.: 167 was cloned into SEQ ID NOS.: 140, 142, 151 and 153 using
SalI and KpnI.
[1200] Oligonucleotides SEQ ID NOS.: 182, 183, 184 and 185 were
used to amplify TrxA residues 2-109 from the E. coli chromosome to
create SEQ ID NO.: 168. Using NotI, TrxA residues 2-109 was cloned
into SEQ ID NOS.: 166 and 167 to create SEQ ID NOS.: 169 and 170,
respectively. SEQ ID NO.: 169 and 170 were cloned into SEQ ID NOS.:
140, 142, 151 and 153 using SalI and KpnI.
Example 22
Methods for Functional GPCR Assay
[1201] Functional G-protein-coupled receptor (GPCR) binding assays
in minicells requires expression of a GPCR of interest into the
minicell membrane bilayer and cytoplasmic expression of the
required G-protein. For these purposes, constructs were created to
co-express both a GPCR and a G-protein. To regulate the ratio of
GPCR to G-protein, transcriptional fusions were created. In these
constructs, the GPCR and G-protein are co-transcribed as a
bi-cistronic mRNA. To measure the GPCR-G-protein interaction in the
intact minicell, each protein was created as a chimera with a
transactivation domain. For these studies the N-terminal
DNA-binding, activation domain of the ToxR protein from V. cholerae
was fused to the C-terminus of both the GPCR and G-protein.
Finally, to measure the interaction GPCR-G-protein interaction, the
ToxR-activated ctx promoter region was cloned in front of lacZ.
Dimerization of the ToxR DNA-binding region will bind and activate
the ctx promoter. In this construct, heterodimerization of the GPCR
and G-protein will promote dimerization of ToxR that will be
monitored by LacZ expression. Details of these constructs are shown
in Table 29.
30TABLE 29 FUNCTIONAL HUMAN GPCR CONSTRUCTS Protein .sup.a,b
Construct .sup.a,b SEQ ID NO.: .beta.2AR SalI-.beta.2AR-PstI, XhoI
186 GS1.alpha. XhoI-GS1.alpha.-XbaI 187 .beta.2AR-GS1.alpha. fusion
SalI-.beta.2AR-PstI, XhoI-GS1.alpha.-XbaI 188 .beta.2AR-stop
SalI-.beta.2AR-PstI-Stop-S- D-XhoI 189 .beta.2AR-stop-GS1.alpha.
SalI-.beta.2AR-PstI-Stop-SD-Xh- oI-GS1.alpha.-XbaI 190 ToxR
ClaI-ToxR-XbaI 191 GS1.alpha. XhoI-GS1.alpha.-ClaI 192 GS2.alpha.
XhoI-GS2.alpha.-ClaI 193 G.alpha.q XhoI-Gq.alpha.-ClaI 194
Gi.alpha. XhoI-Gi.alpha.-ClaI 195 G.alpha.12/13
XhoI-G.alpha.12/13-ClaI 196 GS1.alpha.-ToxR
XhoI-GS1.alpha.-ClaI-ToxR-XbaI 197 GS2.alpha.-ToxR
XhoI-GS2.alpha.-ClaI-ToxR-XbaI 198 G.alpha.q-ToxR
XhoI-G.alpha.q-ClaI-ToxR-XbaI 199 Gi.alpha.-ToxR
XhoI-Gi.alpha.-ClaI-ToxR-XbaI 200 G.alpha.12/13-ToxR
XhoI-G.alpha.12/13-ClaI-ToxR-XbaI 201 ToxR PstI-ToxR-XhoI 202
.beta.2AR SalI-.beta.2AR-PstI 203 .beta.2AR-ToxR
SalI-.beta.2AR-PstI-ToxR-Stop-SD-XhoI 204 .beta.2AR-ToxR-stop-
SalI-.beta.2AR-PstI-ToxR-Stop-SD-XhoI-GS1.alpha.-ClaI-ToxR-XbaI 205
GS1.alpha.-ToxR Pctx XbaI-Pctx-lacZ homology 206 lacZ Pctx
homology-lacZ-XbaI 207 Pctx::lacZ XbaI-Pctx-lacZ-XbaI 208 .sup.a
"SD" refers to the Shine-Delgarno ribosome-binding sequence and
"ToxR" refers to the transactivation, DNA-binding domain of the
ToxR protein (residues 5-141). .sup.b All mature constructs were
cloned into SalI and XbaI sites of SEQ ID NOS.: 140, 142, 151 and
153.
[1202]
31TABLE 30 OLIGONUCLEOTIDE PRIMER SEQUENCES FOR TABLE 29 SEQ ID
NO.: Primer name 5' to 3' sequence 209 .beta.2AR-1
GGGGCAACCCGGGAACGGCAGCGCC 210 .beta.2AR-2
GCAGTGAGTCATTTGTACTACAATTCCTCC 211 .beta.2AR-1-SalI
CGCGGTCGACATGGGGCAACCCGGGAACGGCAGCGCC 212 .beta.2AR-2-Link-
GGCTCGAGCTGCAGGTTGGTGACCGTCTGGCCACGCTC XhoI
TAGCAGTGAGTCATTTGTACTACAATTCC 213 GS1.alpha.-1
GGGCTGCCTCGGGAACAGTAAGACCGAGG 214 GS1.alpha.-2
GAGCAGCTCGTACTGACGAAGGTGCATGC 215 GS1.alpha.-1-XhoI
GGAGGCCCTCGAGATGGGCTGCCTCGGGAACAGTAAG ACCGAGG 216 GS1.alpha.-2-XbaI
CCTCTAGATTATTATCGATGAGCAGCTCGTACTGACGA AGGTGCATGC 217
GS1.alpha.-2-ClaI CCATCGATGAGCAGCTCGTACTGA- CGAAGGTGCATGC 218
G.alpha.12-1 CCGGGGTGGTGCGGACCCTCAGCCGC 219 G.alpha.12-2
CTGCAGCATGATGTCCTTCAGGTTCTCC 220 G.alpha.12-1-XhoI
GCGGGCTCGAGATGTCCGGGGTGGTGCGGACCCTCAGC CGC 221 G.alpha.12-2-ClaI
GCGCCATCGATCTGCAGCATGATGTCCTTCA- GGTTCTCC 222 G.alpha.q-1
GACTCTGGAGTCCATCATGGCGTGCTGC 223 G.alpha.q-2
CCAGATTGTACTCCTTCAGGTTCAACTGG 224 G.alpha.q-1-XhoI
ATGACTCTGGAGTCCATCATGGCGTGCTGC 225 G.alpha.q-2-ClaI
GCGCCATCGATGACCAGATTGTACTCCTTCAGGTTCAACTGG 226 Gi.alpha.-1
GGGCTGCACCGTGAGCGCCGAGGACAAGG 227 Gi.alpha.-2
CCTTCAGGTTGTTCTTGATGATGACATCGG 228 Gi.alpha.-1-XhoI
ATGGGCTGCACCGTGAGCGCCGAGGACAAGG 229 Gi.alpha.-2-ClaI
GCGCCATCGATGAAGAGGCCGCAGTCCTTCAGGTTGTTCTTGA TGATGACATCGG 230
GS2.alpha.-1 GGGCTGCCTCGGGAACAGTAAGACCGAGG 231 GS2.alpha.-2
GAGCAGCTCGTACTGACGAAGGTGCATGC 232 GS2.alpha.-1-XhoI
ATGGGCTGCCTCGGGAACAGTAAGACCGAGG 233 GS2.alpha.-2-ClaI
GCGCCATCGATGAGCAGCTCGTACTGACGAAGGTGCATGC 234 .beta.2AR-2-Link-
GGCTCGAGGGCCTCCTTGATTATTACTCGAGGGCCTCC Stop-XhoI
TTGATTATTACTGCAGGTTGGTGACCGTCTGGCCACGC
TCTAGCAGTGAGTCATTTGTACTACAATTCC 235 .beta.2AR-2-Link
CCCTGCAGGTTGGTGACCGTCTGGCCACGCTCTAGCAG TGAGTCATTTGTACTACAATTCC 236
Tox (5-141)-1B GGACACAACTCAAAAGAGATATCGATGAGTCATATTGG 237 Tox
(5-141)-2 GAGATGTCATGAGCAGCTTCGTTTTCGCG 238 Tox (5-141)-1-
GCGTGGCCAGACGGTCACCAACCTGCAGGGACACAAC Link TCAAAAGAGATATCG 239 Tox
(5-141)-2- CGGGGATCCTCTAGATTATTAAGAGATGTCATGAGCAG XhoI
CTTCGTTTTCGCG 240 Ctx-1 GGCTGTGGGTAGAAGTGAAACGGGGTTTACCG 241 Ctx-2
CTTTACCATATAATGCTCCCTTTGTTTAACAG 242 Ctx-2-XbaI
CGCGGTCTAGAGGCTGTGGGTAGAAGTGAAACGGGGT TTACCG 243 Ctx-2-LacZ
CGACGGCCAGTGAATCCGTAATCATGGTCTTTACCATA TAATGCTCCCTTTGTTTAACAG 244
LacZ-1 CCATGATTACGGATTCACTGGCC- GTCG 245 LacZ-2
CCAGACCAACTGGTAATGGTAGCGACC 246 LacZ-1-Ctx
GGTAAAGACCATGATTACGGATTCACTGGCCGTCG 247 LacZ-2-XbaI
GCGCCTCTAGAAATACGCCCTTTCGGATGAGGGCGTT
ATTATTTTTGACACCAGACCAACTGGTAATGGTAGCG ACC
[1203] Oligonucleotides SEQ ID NOS.: 209, 210, 211 and 212 were
used to amplify human .beta.2AR from human cDNA to create SEQ ID
NO.: 186. Using SalI and XhoI a translational fusion was made
between .beta.2AR and human GS1.alpha. (SEQ ID NO.: 187) to create
a SEQ ID NO.: 188. SEQ ID NO.: 188 was cloned into SEQ ID NOS.:
140, 142, 151 and 153 using SalI and XbaI.
[1204] Oligonucleotides SEQ ID NOS.: 213, 214, 215 and 216 were
used to amplify human GS1.alpha. from human cDNA to create SEQ ID
NO.: 187. Using XhoI and XbaI a translational fusion was made
between GS1.alpha. and human .beta.2AR (SEQ ID NO.: 186) create SEQ
ID NO.: 188. SEQ ID NO.: 188 was cloned into SEQ ID NOS.: 140, 142,
151 and 153 using SalI and XbaI.
[1205] Oligonucleotides SEQ ID NOS.: 213, 214, 215 and 217 were
used to amplify human GS1.alpha. from human cDNA to create SEQ ID
NO.: 192. Using XhoI and XbaI a translational fusion was made with
ToxR residues 5-141 from Vibrio cholerae (SEQ ID NO.: 191) to
create SEQ ID NO.: 197. To be used to create a transcriptional
fusion with .beta.2AR-ToxR chimeras as shown in SEQ ID NO.: 205 and
future GPCR-ToxR chimeras.
[1206] Oligonucleotides SEQ ID NOS.: 218, 219, 220 and 221 were
used to amplify human G.alpha.12/13 from human cDNA to create SEQ
ID NO.: 196. Using XhoI and XbaI a translational fusion was made
with ToxR residues 5-141 from Vibrio cholerae (SEQ ID NO.: 191) to
create SEQ ID NO.: 201. To be used to create future transcriptional
fusions with GPCR-ToxR chimeras as shown in SEQ ID NO.: 205.
[1207] Oligonucleotides SEQ ID NOS.: 222, 223, 224 and 225 were
used to amplify human G.alpha.q from human cDNA to create SEQ ID
NO.: 194. Using XhoI and XbaI a translational fusion was made with
ToxR residues 5-141 from Vibrio cholerae (SEQ ID NO.: 191) to
create SEQ ID NO.: 199. To be used to create future transcriptional
fusions with GPCR-ToxR chimeras as shown in SEQ ID NO.: 205.
[1208] Oligonucleotides SEQ ID NOS.: 226, 227, 228 and 229 were
used to amplify human Gi.alpha. from human cDNA to create SEQ ID
NO.: 195. Using XhoI and XbaI a translational fusion was made with
ToxR residues 5-141 from Vibrio cholerae (SEQ ID NO.: 191) to
create SEQ ID NO.: 200. To be used to create future transcriptional
fusions with GPCR-ToxR chimeras as shown in SEQ ID NO.: 205.
[1209] Oligonucleotides SEQ ID NOS.: 230, 231, 232 and 233 were
used to amplify human GS2.alpha. from human cDNA to create SEQ ID
NO.: 193. Using XhoI and XbaI a translational fusion was made with
ToxR residues 5-141 from Vibrio cholerae (SEQ ID NO.: 191) to
create SEQ ID NO.: 198. To be used to create future transcriptional
fusions with GPCR-ToxR chimeras as shown in SEQ ID NO.: 205.
[1210] Oligonucleotides SEQ ID NOS.: 209, 210, 211 and 234 were
used to amplify human .beta.2AR from human cDNA to create SEQ ID
NO.: 189. Using SalI and XhoI a transcriptional fusion was made
between .beta.2AR and human GS1.alpha. (SEQ ID NO.: 187) to create
a SEQ ID NO.: 190. SEQ ID NO.: 190 was cloned into SEQ ID NOS.:
140, 142, 151 and 153 using SalI and XbaI.
[1211] Oligonucleotides SEQ ID NOS.: 236, 237, 238 and 239 were
used to amplify bases coinciding with ToxR residues 5-141 from
Vibrio Cholerae to create SEQ ID NO.: 202. Using PstI and XhoI a
translational fusion was made between ToxR and human .beta.2AR (SEQ
ID NO.: 203) to create SEQ ID NO.: 204.
[1212] Oligonucleotides SEQ ID NOS.: 209, 210, 211 and 235 were
used to amplify human .beta.2AR from human cDNA to create SEQ ID
NO.: 203. Using SalI and PstI a translational fusion was made
between .beta.2AR and ToxR (SEQ ID NO.: 202) to create SEQ ID NO.:
204.
[1213] Using oligonucleotides SEQ ID NOS.: 197 and 204
transcriptional fusions were created between the .beta.2AR-ToxR
translational fusion (SEQ ID NO.: 204) and the GS1.alpha.-ToxR
translational fusion (SEQ ID NO.: 197) to create SEQ ID NO.:
205.
[1214] Oligonucleotides SEQ ID NOS.: 240, 241, 242 and 243 were
used to amplify the ctx promoter region (Pctx) from Vibrio cholerae
to create SEQ ID NO.: 206. Combining this PCR product in
combination with the SEQ ID NO.: 207 PCR product and amplifying in
the presence of SEQ ID NOS.: 242, 247, SEQ ID NO.: 208 was created.
Using XbaI, the SEQ ID NO.: 208 reporter construct was subsequently
cloned into pACYC184 for co-transformation with the GPCR-G-protein
fusions constructs above.
[1215] Oligonucleotides SEQ ID NOS.: 244, 245, 246 and 247 were
used to amplify the lacZ from E. coli to create SEQ ID NO.: 207.
Combining this PCR product in combination with the SEQ ID NO.: 206
PCR product and amplifying in the presence of SEQ ID NOS.: 242 and
247, SEQ ID NO.: 208 was created. Using XbaI, the 208 reporter
construct was subsequently cloned into pACYC184 for
co-transformation with the GPCR-G-protein fusions constructs
above.
Example 23
Modular Membrane-Targeting and Solubilization Expression
Constructs
[1216] To produce membrane proteins efficiently in minicells it may
be necessary to create chimeric fusions with the membrane protein
of interest. In this Example various regions of the MaIE protein
have been cloned into a modular expression system designed to
create chimeric fusions with direct difficult to target membrane
proteins to produce leader domains that will direct the proteins to
the cytoplasmic membrane ( Miller, K., W., et al. 1998. Production
of active chimeric pediocin AcH in Escherichia coli in the absence
of processing and secretion genes from the Pediococcus pap operon.
Appl. Environ. Microbiol. 64:14-20). Similarly, a modified version
of the TrxA protein has also been cloned into this modular
expression system to create chimeric fusions with proteins that are
difficult to maintain in a soluble conformation (LaVallie, E. R.,
et al. 1993. A thioredoxin gene fusion expression system that
circumvents inclusion body formation in the E. coli cytoplasm.
Biotechnology (N.Y.) 11:187-193). Table 31 describes each of these
modular constructs.
32TABLE 31 MODULAR MEMBRANE-TARGETING AND SOLUBILIZATION EXPRESSION
CONSTRUCTS Protein .sup.a Construct .sup.a SEQ ID NO MalE (1-28)
NsiI-MalE(1-28)-Factor Xa-PstI, SalI, XbaI-FLAG, NheI 248 MalE
(1-370, del 354- NsiI-MalE(1-370, del 354-364)-Factor Xa-PstI,
SalI, XbaI-FLAG, 249 364) NheI TrxA (2-109, del 103- PstI, SalI,
XbaI-TrxA(2-109, del 103-107)-FLAG-NheI 250 107) MalE (1-28)-TrxA
(2- NsiI-MalE(1-28)-Factor Xa-PstI, SalI, XbaI-TrxA (2-109 del 103-
251 109, del 103-107) 107)-FLAG, NheI MalE (1-370, del 354-
NsiI-MalE(1-370, del 354-364)-Factor Xa-PstI, SalI, XbaI-TrxA (2-
252 364)-TrxA (2-109, del 109 del 103-107)-FLAG, NheI 103-107)
.sup.a The term "del" refers to a deletion in which amino acid
residues following the term "del" are removed from the
sequence.
[1217]
33TABLE 32 OLIGONUCLEOTIDE PRIMER SEQUENCES FOR TABLE 31. SEQ ID
NO.: Primer name 5' to 3' sequence 253 MalE-1-NsiI
CGCGGATGCATATGAAAATAAAAACAGGTGCACGCATCCTCGCATTT
ATCCGCATTAACGACGATGATGTTTTCCGCCTCGGCTCTCGCC 254 MalE-2-middle
CGTCGACCGAGGCCTGCAGGCGGGCTTCGATGATTTTGGCGAG
AGCCGAGGCGGAAAACATCATCGTCG 255 MalE-3s-NheI
CGAAGCCCGCCTGCAGGCCTCGGTCGACGCCGAATCTAGAGATTAT
AAAGATGACGATGACAAATAATAAGCTAGCGGCGC 256 MalE-4-NheI
GCGCCGCTAGCTTATTATTTGTCATCG 257 MalE-1a GGTGCACGCATCCTCGCATTATCCGC
258 MalE-2a GGCGTTTTCCATGGTGGCGGCAATACGTGG 259 MalE-1-NsiI
CGCGGATGCATATGAAAATAAAAACAGGTGCACGCATCCTC GCATTATCCGC 260
MalE-2-NheI CCGAGGCCTGCAGGCGGGCTTCGATACGCACGGCATACCAG
AAAGCGGACTGGGCGTTTTCCATGGTGGCGGCAATACGTGG 261 MalE-3L-NheI
GCGCCGCTAGCTTATTATTTGTCATCGTCATCTTTATAATCTC
TAGATTCGGCGTCGACCGAGGCCTGCAGGCGGGCTTCGATA CGC 262 TrxA-1a
CCTGACTGACGACAGTTTTGACACGG 263 TrxA-2a
CCTTTAGACAGTGCACCCACTTTGGTTGCCGC 264 TrxA-1a-PstI
CGCGGCTGCAGGCCTCGGTCGACGCCGAATCTAGAAGCGAT
AAAATTATTCACCTGACTGACGACAGTTTTGACACGG 265 TrxA-2-NheI
GCGCCGCTAGCTTATTATTTGTCATCGTCATCTTTATAATCCG
CCAGGTTCTCTTTCAACTGACCTTTAGACAGTGCACCCACTTT GGTTGCCGC
[1218] Oligonucleotides SEQ ID NOS.: 253, 254, 255 and 256 overlap
with each other to form a scaffold template to PCR amplify malE
(1-28) to create a SEQ ID NO.: 248. Following PCR amplification,
SEQ ID NO.: 248 was digested with NsiI and NheI and cloned into SEQ
ID NOS.: 152, 154, 139 and 141 digested with PstI and XbaI. The
resultant products create SEQ ID NOS.: 266, 267, 268 and 269,
respectively, that lose both the 5-prime PstI and 3-prime XbaI
restriction site and retain the PstI, SalI, and XbaI restriction
sites between MalE (1-28) and the FLAG sequence. Insertion of a
protein in alignment with these sites results in a chimeric protein
containing amino-terminal MalE (1-28) and carboxy-terminal
FLAG.
[1219] Oligonucleotides SEQ ID NOS. 257, 258, 259 and 260 were used
to amplify malE (1-370 with a deletion removing residues 354-364)
to create SEQ ID NO.: 249. Following PCR amplification, SEQ ID NO.:
249 Was digested with NsiI and NheI and cloned into SEQ ID NOS.:
152, 154, 139 and 141 digested with PstI and XbaI. The resultant
products create SEQ ID NOS.: 270, 271, 272 and 273, respectively,
that lose both the 5-prime PstI and 3-prime XbaI restriction site
and retain the PstI, SalI, and XbaI restriction sites between MalE
(1-370, del 354-364) and the FLAG sequence. Insertion of a protein
in alignment with these sites results in a chimeric protein
containing amino-terminal MalE (1-370, del 354-364) and
carboxy-terminal FLAG.
[1220] Oligonucleotides SEQ ID NOS.: 262, 263, 264 and 265 were
used to amplify trxA (2-109 with a deletion removing residues
103-107) to create SEQ ID NO.: 250. Following PCR amplification,
SEQ ID NO.: 250 was digested with PstI and NheI and cloned into SEQ
ID NOS.: 152, 154, 139 and 141 digested with PstI and XbaI. to
create SEQ ID NOS.: 274, 275, 276 and 277, respectively. Using
these restriction digestion combinations results in loss of the
XbaI SEQ ID NO.: 249 insertion site.
[1221] The resultant products create SEQ ID NOS.: 274, 275, 276 and
277, respectively, that lose the 3-prime XbaI restriction site and
retain the PstI, SalI, and XbaI restriction sites on the 3-prime
end of the TrxA (1-109, del 103-107) sequence. Insertion of a
protein in alignment with these sites results in a chimeric protein
containing Carboxy-terminal TrxA (1-109, del 103-107)-FLAG.
[1222] SEQ ID NO.: 248 was digested with NsiI and XbaI and cloned
into SEQ ID NOS.: 274, 275, 276 and 277 that were digested with
PstI and XbaI. The resultant products create SEQ ID NOS.: 278, 279,
280 and 281, respectively, that lose the 5 prime PstI restriction
site and retain the PstI, SalI, and XbaI restriction sites between
MalE (1-28) and TrxA (1-109, del 103-107). Insertion of a protein
in alignment with these sites results in a chimeric protein
containing amino-terminal MalE (1-28) and carboxy-terminal TrxA
(1-109, del 103-107)-FLAG.
[1223] SEQ ID NO.: 249 was digested with NsiI and XbaI and cloned
into SEQ ID NOS.: 274, 275, 276 and 277 that were digested with
PstI and XbaI. The resultant products create SEQ ID NOS.: 282, 283,
284 and 285, respectively, that lose the 5 prime PstI restriction
site and retain the PstI, SalI, and XbaI restriction sites between
MalE (1-370, del 354-364) and TrxA (1-109, del 103-107). Inserti a
protein in alignment with these sites results in a chimeric protein
containing amino-terminal MalE (1-370, del 354-364) and
carboxy-terminal TrxA (1-109, del 103-107)-FLAG.
Example 24
Poroplast.TM. Formation
[1224] Minicells are used to prepare Poroplasts in order to
increase the accessibility of a membrane protein component and/or
domain to the outside environment. Membrane proteins in the inner
membrane are accessible for ligand binding and/or other
interactions in poroplasts, due to the absence of an outer
membrane. The removal of the outer membrane from E. coli whole
cells and minicells to produce poroplasts was carried out using
modifications of previously described protoplast and analysis
protocols (Birdsell et al., Production and Ultrastructure of
Lysozyme and Ethylenediaminetetraacetate-Lysozyme Spheroplasts of
Escherichia coli, J. Bacteriol. 93:427-437, 1967; Weiss et al.,
Protoplast Formation in Escherichia Coli, J. Bacteriol.
128:668-670, 1976; Matsuyama, S-I., et al. SecD is involved in the
release of translocated secretory proteins from the cytoplasmic
membrane of Escherichia coli. 12:265-270, 1993).
[1225] In brief, cells were grown to late-log phase and pelleted at
room temperature. Minicells were also isolated from cultures in
late-log phase. The pellet was washed twice with 50 mM Tris, pH
8.0. Following the second wash, 1.times.10.sup.9 cells were
resuspended in 1 ml 50 mM Tris (pH 8.0) that contained 8% sucrose
and 2 mM EDTA. Cell/EDTA/sucrose mixtures were incubated at
37.degree. C. for 10 min, centrifuged, decanted, and poroplasted
cells were resuspended in 50 mM Tris, pH 8.0 with 8% sucrose.
Incubation with anti-LPS-coated magnetic beads, as described in
Example 14, is used to enrich for poroplasts that lack LPS.
Following incubation with the resuspended protoplasted cells, the
anti-LPS magnetic beads were removed from suspension with a
magnet.
[1226] To examine the range of molecular sizes that can pass
through the cell wall, an IgG molecule was tested for its ability
to pass the intact cell wall. Binding of an antibody to the
ToxR-PhoA chimera expressed on the inner membrane minicell
poroplasts was measured. Briefly, minicell poroplasts with and
without inner membrane-bound ToxR-PhoA were incubated at 37.degree.
C. with anti-PhoA antibody in reaction buffer (50 mM Tris, pH 8.0,
8% sucrose, 1% BSA, and 0.01% Tween-20). Following incubation,
poroplasts were centrifuged, washed 3 times with reaction buffer,
and resuspended in 50 mM Tris, pH 8.0 with 8% sucrose. Following
resuspension, bound proteins from 5.times.10.sup.7 minicells or
minicell poroplasts were separated using denaturing SDS-PAGE,
transferred to nitrocellulose, and developed using with both
anti-PhoA antibody and secondary antibody against both heavy and
light chains of anti-PhoA IgG (Table 33).
34TABLE 33 ANTI-PHOA ACCESSIBILITY TO POROPLAST INNER
MEMBRANE-BOUND TOXR-PHOA EDTA (mM) 0 2 0 2 Lysozyme (mg/ml) 0 0 5 5
Poroplasts (ng antibody bound) Protoplasts (ng antibody bound)
Minicells ToxR- ND .sup.a 0.6 ND .sup.a 12.8 PhoA Minicells only ND
.sup.a ND .sup.a ND .sup.a ND .sup.a .sup.a Non-detectable
[1227] These results demonstrate that the cell wall present on
poroplasts is penetrable by an IgG molecule and that an IgG
molecule is capable of passing the intact cell wall and binding to
an inner membrane protein. From this data it appeats that poroplast
operate at .about.10% the efficiency of protoplasts by allowing 0.6
ng of IgG to bind inner membrane-bound ToxR-PhoA compared to 12.8
ng. However, given the large size of IgG (.about.150,000 Daltons)
it is expected that molecules having a smaller molecular weight
will efficiently access inner membrane proteins in poroplasts.
Example 25
Production of Neurotensin Receptor (NTR)
[1228] To demonstrate expression of NTR in isolated minicells,
MalE(L)-NTR (SEQ ID NO.: 166 was cloned into pMPX-67 (SEQ ID NO.:
151). Following minicell isolation, 1.5.times.10.sup.9 minicells
were induced with 1 mM Rhamnose for 2 hour at 37.degree. C.
Following induction, the protein produced was visualized via
Western analysis using an anti-MalE antibody following separation
on an SDS-PAGE. The results are shown in FIG. 2.
[1229] These data demonstrates that MalE(L)-NTR is induced 87-fold
by addition of 1 mM rhamnose to the minicell induction mixture.
Cross-reactive proteins are host MalE and non-specific binding by
Goat-anti-mouse HRP secondary antibody.
[1230] The contents of the articles, patents, and patent
applications, and all other documents and electronically available
information mentioned or cited herein, are hereby incorporated by
reference in their entirety to the same extent as if each
individual publication was specifically and individually indicated
to be incorporated by reference. Applicants reserve the right to
physically incorporate into this application any and all materials
and information from any such articles, patents, patent
applications, or other documents.
[1231] The inventions illustratively described herein may suitably
be practiced in the absence of any element or elements, limitation
or limitations, not specifically disclosed herein. Thus, for
example, the terms "comprising", "including", containing", etc.
shall be read expansively and without limitation. Additionally, the
terms and expressions employed herein have been used as terms of
description and not of limitation, and there is no intention in the
use of such terms and expressions of excluding any equivalents of
the features shown and described or portions thereof, but it is
recognized that various modifications are possible within the scope
of the invention claimed. Thus, it should be understood that
although the present invention has been specifically disclosed by
preferred embodiments and optional features, modification and
variation of the inventions embodied therein herein disclosed may
be resorted to by those skilled in the art, and that such
modifications and variations are considered to be within the scope
of this invention.
[1232] The invention has been described broadly and generically
herein. Each,of the narrower species and subgeneric groupings
falling within the generic disclosure also form part of the
invention. This includes the generic description of the invention
with a proviso or negative limitation removing any subject matter
from the genus, regardless of whether or not the excised material
is specifically recited herein.
[1233] Other embodiments are within the following claims. In
addition, where features or aspects of the invention are described
in terms of Markush groups, those skilled in the art will recognize
that the invention is also thereby described in terms of any
individual member or subgroup of members of the Markush group.
Sequence CWU 1
1
258 1 1260 DNA E. coli 1 ccatacccgt ttttttgggc tagcaggagg
aattcaccct gcagatgttt gaaccaatgg 60 aacttaccaa tgacgcggtg
attaaagtca tcggcgtcgg cggcggcggc ggtaatgctg 120 ttgaacacat
ggtgcgcgag cgcattgaag gtgttgaatt cttcgcggta aataccgatg 180
cacaagcgct gcgtaaaaca gcggttggac agacgattca aatcggtagc ggtatcacca
240 aaggactggg cgctggcgct aatccagaag ttggccgcaa tgcggctgat
gaggatcgcg 300 atgcattgcg tgcggcgctg gaaggtgcag acatggtctt
tattgctgcg ggtatgggtg 360 gtggtaccgg tacaggtgca gcaccagtcg
tcgctgaagt ggcaaaagat ttgggtatcc 420 tgaccgttgc tgtcgtcact
aagcctttca actttgaagg caagaagcgt atggcattcg 480 cggagcaggg
gatcactgaa ctgtccaagc atgtggactc tctgatcact atcccgaacg 540
acaaactgct gaaagttctg ggccgcggta tctccctgct ggatgcgttt ggcgcagcga
600 acgatgtact gaaaggcgct gtgcaaggta tcgctgaact gattactcgt
ccgggtttga 660 tgaacgtgga ctttgcagac gtacgcaccg taatgtctga
gatgggctac gcaatgatgg 720 gttctggcgt ggcgagcggt gaagaccgtg
cggaagaagc tgctgaaatg gctatctctt 780 ctccgctgct ggaagatatc
gacctgtctg gcgcgcgcgg cgtgctggtt aacatcacgg 840 cgggcttcga
cctgcgtctg gatgagttcg aaacggtagg taacaccatc cgtgcatttg 900
cttccgacaa cgcgactgtg gttatcggta cttctcttga cccggatatg aatgacgagc
960 tgcgcgtaac cgttgttgcg acaggtatcg gcatggacaa acgtcctgaa
atcactctgg 1020 tgaccaataa gcaggttcag cagccagtga tggatcgcta
ccagcagcat gggatggctc 1080 cgctgaccca ggagcagaag ccggttgcta
aagtcgtgaa tgacaatgcg ccgcaaactg 1140 cgaaagagcc ggattatctg
gatatcccag cattcctgcg taagcaagct gattaataat 1200 ctagaggatc
cccgggtacc gagctcgaat tcgtaatcat ggtcatagct gtttcctgtg 1260 2 1260
DNA E. coli 2 gaattcaggc gctttttaga ctggtcgtaa tgaaattcag
caggatcaca ttctgcagat 60 gtttgaacca atggaactta ccaatgacgc
ggtgattaaa gtcatcggcg tcggcggcgg 120 cggcggtaat gctgttgaac
acatggtgcg cgagcgcatt gaaggtgttg aattcttcgc 180 ggtaaatacc
gatgcacaag cgctgcgtaa aacagcggtt ggacagacga ttcaaatcgg 240
tagcggtatc accaaaggac tgggcgctgg cgctaatcca gaagttggcc gcaatgcggc
300 tgatgaggat cgcgatgcat tgcgtgcggc gctggaaggt gcagacatgg
tctttattgc 360 tgcgggtatg ggtggtggta ccggtacagg tgcagcacca
gtcgtcgctg aagtggcaaa 420 agatttgggt atcctgaccg ttgctgtcgt
cactaagcct ttcaactttg aaggcaagaa 480 gcgtatggca ttcgcggagc
aggggatcac tgaactgtcc aagcatgtgg actctctgat 540 cactatcccg
aacgacaaac tgctgaaagt tctgggccgc ggtatctccc tgctggatgc 600
gtttggcgca gcgaacgatg tactgaaagg cgctgtgcaa ggtatcgctg aactgattac
660 tcgtccgggt ttgatgaacg tggactttgc agacgtacgc accgtaatgt
ctgagatggg 720 ctacgcaatg atgggttctg gcgtggcgag cggtgaagac
cgtgcggaag aagctgctga 780 aatggctatc tcttctccgc tgctggaaga
tatcgacctg tctggcgcgc gcggcgtgct 840 ggttaacatc acggcgggct
tcgacctgcg tctggatgag ttcgaaacgg taggtaacac 900 catccgtgca
tttgcttccg acaacgcgac tgtggttatc ggtacttctc ttgacccgga 960
tatgaatgac gagctgcgcg taaccgttgt tgcgacaggt atcggcatgg acaaacgtcc
1020 tgaaatcact ctggtgacca ataagcaggt tcagcagcca gtgatggatc
gctaccagca 1080 gcatgggatg gctccgctga cccaggagca gaagccggtt
gctaaagtcg tgaatgacaa 1140 tgcgccgcaa actgcgaaag agccggatta
tctggatatc ccagcattcc tgcgtaagca 1200 agctgattaa taatctagag
gatccccggg taccgagctc gaattcgtaa tcatggtcat 1260 3 2544 DNA
Artificial Sequence Gene encoding a fusion protein 3 aagcctgcat
tgcggcgctt cagtctccgc tgcatactgt cccgttacca attatgacaa 60
cttgacggct acatcattca ctttttcttc acaaccggca cggaactcgc tcgggctggc
120 cccggtgcat tttttaaata cccgcgagaa atagagttga tcgtcaaaac
caacattgcg 180 accgacggtg gcgataggca tccgggtggt gctcaaaagc
agcttcgcct ggctgatacg 240 ttggtcctcg cgccagctta agacgctaat
ccctaactgc tggcggaaaa gatgtgacag 300 acgcgacggc gacaagcaaa
catgctgtgc gacgctggcg atatcaaaat tgctgtctgc 360 caggtgatcg
ctgatgtact gacaagcctc gcgtacccga ttatccatcg gtggatggag 420
cgactcgtta atcgcttcca tgcgccgcag taacaattgc tcaagcagat ttatcgccag
480 cagctccgaa tagcgccctt ccccttgccc ggcgttaatg atttgcccaa
acaggtcgct 540 gaaatgcggc tggtgcgctt catccgggcg aaagaacccc
gtattggcaa atattgacgg 600 ccagttaagc cattcatgcc agtaggcgcg
cggacgaaag taaacccact ggtgatacca 660 ttcgcgagcc tccggatgac
gaccgtagtg atgaatctct cctggcggga acagcaaaat 720 atcacccggt
cggcaaacaa attctcgtcc ctgatttttc accaccccct gaccgcgaat 780
ggtgagattg agaatataac ctttcattcc cagcggtcgg tcgataaaaa aatcgagata
840 accgttggcc tcaatcggcg ttaaacccgc caccagatgg gcattaaacg
agtatcccgg 900 cagcagggga tcattttgcg cttcagccat acttttcata
ctcccgccat tcagagaaga 960 aaccaattgt ccatattgca tcagacattg
ccgtcactgc gtcttttact ggctcttctc 1020 gctaaccaaa ccggtaaccc
cgcttattaa aagcattctg taacaaagcg ggaccaaagc 1080 catgacaaaa
acgcgtaaca aaagtgtcta taatcacggc agaaaagtcc acattgatta 1140
tttgcacggc gtcacacttt gctatgccat agcattttta tccataagat tagcggatcc
1200 tacctgacgc tttttatcgc aactctctac tgtttctcca tacccgtttt
tttgggctag 1260 caggaggaat tcaccctgca gatgtttgaa ccaatggaac
ttaccaatga cgcggtgatt 1320 aaagtcatcg gcgtcggcgg cggcggcggt
aatgctgttg aacacatggt gcgcgagcgc 1380 attgaaggtg ttgaattctt
cgcggtaaat accgatgcac aagcgctgcg taaaacagcg 1440 gttggacaga
cgattcaaat cggtagcggt atcaccaaag gactgggcgc tggcgctaat 1500
ccagaagttg gccgcaatgc ggctgatgag gatcgcgatg cattgcgtgc ggcgctggaa
1560 ggtgcagaca tggtctttat tgctgcgggt atgggtggtg gtaccggtac
aggtgcagca 1620 ccagtcgtcg ctgaagtggc aaaagatttg ggtatcctga
ccgttgctgt cgtcactaag 1680 cctttcaact ttgaaggcaa gaagcgtatg
gcattcgcgg agcaggggat cactgaactg 1740 tccaagcatg tggactctct
gatcactatc ccgaacgaca aactgctgaa agttctgggc 1800 cgcggtatct
ccctgctgga tgcgtttggc gcagcgaacg atgtactgaa aggcgctgtg 1860
caaggtatcg ctgaactgat tactcgtccg ggtttgatga acgtggactt tgcagacgta
1920 cgcaccgtaa tgtctgagat gggctacgca atgatgggtt ctggcgtggc
gagcggtgaa 1980 gaccgtgcgg aagaagctgc tgaaatggct atctcttctc
cgctgctgga agatatcgac 2040 ctgtctggcg cgcgcggcgt gctggttaac
atcacggcgg gcttcgacct gcgtctggat 2100 gagttcgaaa cggtaggtaa
caccatccgt gcatttgctt ccgacaacgc gactgtggtt 2160 atcggtactt
ctcttgaccc ggatatgaat gacgagctgc gcgtaaccgt tgttgcgaca 2220
ggtatcggca tggacaaacg tcctgaaatc actctggtga ccaataagca ggttcagcag
2280 ccagtgatgg atcgctacca gcagcatggg atggctccgc tgacccagga
gcagaagccg 2340 gttgctaaag tcgtgaatga caatgcgccg caaactgcga
aagagccgga ttatctggat 2400 atcccagcat tcctgcgtaa gcaagctgat
taataatcta gaggcgttac caattatgac 2460 aacttgacgg gaagttccta
tactttctag agaataggaa cttcccaaag ccagtatcaa 2520 ctcagacaaa
ggcaaagcat cttg 2544 4 3350 DNA Artificial Sequence Gene encoding a
fusion protein 4 aagcctgcat tgcggcgctt cagtctccgc tgcatactgt
ccttaatctt tctgcgaatt 60 gagatgacgc cactggctgg gcgtcatccc
ggtttcccgg gtaaacacca ccgaaaaata 120 gttactatct tcaaagccac
attcggtcga aatatcactg attaacaggc ggctatgctg 180 gagaagatat
tgcgcatgac acactctgac ctgtcgcaga tattgattga tggtcattcc 240
agtctgctgg cgaaattgct gacgcaaaac gcgctcactg cacgatgcct catcacaaaa
300 tttatccagc gcaaagggac ttttcaggct agccgccagc cgggtaatca
gcttatccag 360 caacgtttcg ctggatgttg gcggcaacga atcactggtg
taacgatggc gattcagcaa 420 catcaccaac tgcccgaaca gcaactcagc
catttcgtta gcaaacggca catgctgact 480 actttcatgc tcaagctgac
cgataacctg ccgcgcctgc gccatcccca tgctacctaa 540 gcgccagtgt
ggttgccctg cgctggcgtt aaatcccgga atcgccccct gccagtcaag 600
attcagcttc agacgctccg ggcaataaat aatattctgc aaaaccagat cgttaacgga
660 agcgtaggag tgtttatcgt cagcatgaat gtaaaagaga tcgccacggg
taatgcgata 720 agggcgatcg ttgagtacat gcaggccatt accgcgccag
acaatcacca gctcacaaaa 780 atcatgtgta tgttcagcaa agacatcttg
cggataacgg tcagccacag cgactgcctg 840 ctggtcgctg gcaaaaaaat
catctttgag aagttttaac tgatgcgcca ccgtggctac 900 ctcggccaga
gaacgaagtt gattattcgc aatatggcgt acaaatacgt tgagaagatt 960
cgcgttattg cagaaagcca tcccgtccct ggcgaatatc acgcggtgac cagttaaact
1020 ctcggcgaaa aagcgtcgaa aagtggttac tgtcgctgaa tccacagcga
taggcgatgt 1080 cagtaacgct ggcctcgctg tggcgtagca gatgtcgggc
tttcatcagt cgcaggcggt 1140 tcaggtatcg ctgaggcgtc agtcccgttt
gctgcttaag ctgccgatgt agcgtacgca 1200 gtgaaagaga aaattgatcc
gccacggcat cccaattcac ctcatcggca aaatggtcct 1260 ccagccaggc
cagaagcaag ttgagacgtg atgcgctgtt ttccaggttc tcctgcaaac 1320
tgcttttacg cagcaagagc agtaattgca taaacaagat ctcgcgactg gcggtcgagg
1380 gtaaatcatt ttccccttcc tgctgttcca tctgtgcaac cagctgtcgc
acctgctgca 1440 atacgctgtg gttaacgcgc cagtgagacg gatactgccc
atccagctct tgtggcagca 1500 actgattcag cccggcgaga aactgaaatc
gatccggcga gcgatacagc acattggtca 1560 gacacagatt atcggtatgt
tcatacagat gccgatcatg atcgcgtacg aaacagaccg 1620 tgccaccggt
gatggtatag ggctgcccat taaacacatg aatacccgtg ccatgttcga 1680
caatcacaat ttcatgaaaa tcatgatgat gttcaggaaa atccgcctgc gggagccggg
1740 gttctatcgc cacggacgcg ttaccagacg gaaaaaaatc cacactatgt
aatacggtca 1800 tactggcctc ctgatgtcgt caacacggcg aaatagtaat
cacgaggtca ggttcttacc 1860 ttaaattttc gacggaaaac cacgtaaaaa
acgtcgattt ttcaagatac agcgtgaatt 1920 ttcaggaaat gcggtgagca
tcacatcacc acaattcagc aaattgtgaa catcatcacg 1980 ttcatctttc
cctggttgcc aatggcccat tttcctgtca gtaacgagaa ggtcgcgaat 2040
tcaggcgctt tttagactgg tcgtaatgaa attcagcagg atcacatatg tttgaaccaa
2100 tggaacttac caatgacgcg gtgattaaag tcatcggcgt cggcggcggc
ggcggtaatg 2160 ctgttgaaca catggtgcgc gagcgcattg aaggtgttga
attcttcgcg gtaaataccg 2220 atgcacaagc gctgcgtaaa acagcggttg
gacagacgat tcaaatcggt agcggtatca 2280 ccaaaggact gggcgctggc
gctaatccag aagttggccg caatgcggct gatgaggatc 2340 gcgatgcatt
gcgtgcggcg ctggaaggtg cagacatggt ctttattgct gcgggtatgg 2400
gtggtggtac cggtacaggt gcagcaccag tcgtcgctga agtggcaaaa gatttgggta
2460 tcctgaccgt tgctgtcgtc actaagcctt tcaactttga aggcaagaag
cgtatggcat 2520 tcgcggagca ggggatcact gaactgtcca agcatgtgga
ctctctgatc actatcccga 2580 acgacaaact gctgaaagtt ctgggccgcg
gtatctccct gctggatgcg tttggcgcag 2640 cgaacgatgt actgaaaggc
gctgtgcaag gtatcgctga actgattact cgtccgggtt 2700 tgatgaacgt
ggactttgca gacgtacgca ccgtaatgtc tgagatgggc tacgcaatga 2760
tgggttctgg cgtggcgagc ggtgaagacc gtgcggaaga agctgctgaa atggctatct
2820 cttctccgct gctggaagat atcgacctgt ctggcgcgcg cggcgtgctg
gttaacatca 2880 cggcgggctt cgacctgcgt ctggatgagt tcgaaacggt
aggtaacacc atccgtgcat 2940 ttgcttccga caacgcgact gtggttatcg
gtacttctct tgacccggat atgaatgacg 3000 agctgcgcgt aaccgttgtt
gcgacaggta tcggcatgga caaacgtcct gaaatcactc 3060 tggtgaccaa
taagcaggtt cagcagccag tgatggatcg ctaccagcag catgggatgg 3120
ctccgctgac ccaggagcag aagccggttg ctaaagtcgt gaatgacaat gcgccgcaaa
3180 ctgcgaaaga gccggattat ctggatatcc cagcattcct gcgtaagcaa
gctgattaat 3240 aatctagagg cgttaccaat tatgacaact tgacgggaag
ttcctatact ttctagagaa 3300 taggaacttc ccaaagccag tatcaactca
gacaaaggca aagcatcttg 3350 5 2280 DNA Artificial Sequence Gene
encoding a fusion protein 5 aagcctgcat tgcggcgctt cagtctccgc
tgcatactgt ccttaataaa gtgagtcgat 60 attgtctttg ttgaccagta
ataccttatg gaaacggata attcgcttat ccatatctac 120 gtcggcctta
cccagattct gcatttctaa tccaggcttg atctcttcac ccttcagcaa 180
cgtgctggcg acggctgcga gtgcgtaacc tgcagaggcc ggatcgtaag taatcccttc
240 ggtgatatca ccacttttaa tcagtgatgc cgcctgtgaa gggatcatca
tgccatagac 300 tgcgacttta tttttcgccc gtttctcttt caccgcacgt
cccgcgccaa tcggaccgtt 360 tgaaccaaag gagacaaccg ctttcaagtc
aggataggtt ttcatcaggt ccagtgtagt 420 acgacgtgag acatccacac
tctcggcaac cggcatgcgg cgggtaactt catgcatatc 480 cgggtaatgc
tctttctggt atttcaccag caagtcagcc cataagttat gctgcggcac 540
ggtcaaacta cccacgtaaa tcacatagcc gcccttgcca cccatgcgtt tcgccatatg
600 ctcaacatat tcagcggcaa atttttcgtt atcaatgatt tcgatatccc
agttagcact 660 tggctgaccg ggggattcgt tggtcagaac cacaattccg
gcatctcgcg cttttttgaa 720 taccggttcc agcacgttgg catcgtttgg
cacgatagta attgcattaa ccttacgggc 780 gattaaatcc tcaataattt
taacttgttg cggagcatca gtacttgaag gccccacctg 840 tgaggcatta
acaccaaagg ctttacccgc ctcaaccaca ccttcgccca tgcgattaaa 900
ccacggcata ccatcgactt tagaaatatt caccacgact ttttccgctg cctggagcgg
960 cgcagaaatt agcgcagcgc ctaataacag cgaagacacc atattgataa
caaaacgttt 1020 attcatcata tggaacttac caatgacgcg gtgattaaag
tcatcggcgt cggcggcggc 1080 ggcggtaatg ctgttgaaca catggtgcgc
gagcgcattg aaggtgttga attcttcgcg 1140 gtaaataccg atgcacaagc
gctgcgtaaa acagcggttg gacagacgat tcaaatcggt 1200 agcggtatca
ccaaaggact gggcgctggc gctaatccag aagttggccg caatgcggct 1260
gatgaggatc gcgatgcatt gcgtgcggcg ctggaaggtg cagacatggt ctttattgct
1320 gcgggtatgg gtggtggtac cggtacaggt gcagcaccag tcgtcgctga
agtggcaaaa 1380 gatttgggta tcctgaccgt tgctgtcgtc actaagcctt
tcaactttga aggcaagaag 1440 cgtatggcat tcgcggagca ggggatcact
gaactgtcca agcatgtgga ctctctgatc 1500 actatcccga acgacaaact
gctgaaagtt ctgggccgcg gtatctccct gctggatgcg 1560 tttggcgcag
cgaacgatgt actgaaaggc gctgtgcaag gtatcgctga actgattact 1620
cgtccgggtt tgatgaacgt ggactttgca gacgtacgca ccgtaatgtc tgagatgggc
1680 tacgcaatga tgggttctgg cgtggcgagc ggtgaagacc gtgcggaaga
agctgctgaa 1740 atggctatct cttctccgct gctggaagat atcgacctgt
ctggcgcgcg cggcgtgctg 1800 gttaacatca cggcgggctt cgacctgcgt
ctggatgagt tcgaaacggt aggtaacacc 1860 atccgtgcat ttgcttccga
caacgcgact gtggttatcg gtacttctct tgacccggat 1920 atgaatgacg
agctgcgcgt aaccgttgtt gcgacaggta tcggcatgga caaacgtcct 1980
gaaatcactc tggtgaccaa taagcaggtt cagcagccag tgatggatcg ctaccagcag
2040 catgggatgg ctccgctgac ccaggagcag aagccggttg ctaaagtcgt
gaatgacaat 2100 gcgccgcaaa ctgcgaaaga gccggattat ctggatatcc
cagcattcct gcgtaagcaa 2160 gctgattaat aatctagagg cgttaccaat
tatgacaact tgacgggaag ttcctattct 2220 ctagaaagta taggaacttc
ccaaagccag tatcaactca gacaaaggca aagcatcttg 2280 6 4728 DNA
Artificial Sequence Expression vector 6 tcgcgcgttt cggtgatgac
ggtgaaaacc tctgacacat gcagctcccg gagacggtca 60 cagcttgtct
gtaagcggat gccgggagca gacaagcccg tcagggcgcg tcagcgggtg 120
ttggcgggtg tcggggctgg cttaactatg cggcatcaga gcagattgta ctgagagtgc
180 accatatgcg gtgtgaaata ccgcacagat gcgtaaggag aaaataccgc
atcaggcgcc 240 attcgccatt caggctgcgc aactgttggg aagggcgatc
ggtgcgggcc tcttcgctat 300 tacgccagct ggcgaaaggg ggatgtgctg
caaggcgatt aagttgggta acgccagggt 360 tttcccagtc acgacgttgt
aaaacgacgg ccagtgccaa gcttaattaa tctttctgcg 420 aattgagatg
acgccactgg ctgggcgtca tcccggtttc ccgggtaaac accaccgaaa 480
aatagttact atcttcaaag ccacattcgg tcgaaatatc actgattaac aggcggctat
540 gctggagaag atattgcgca tgacacactc tgacctgtcg cagatattga
ttgatggtca 600 ttccagtctg ctggcgaaat tgctgacgca aaacgcgctc
actgcacgat gcctcatcac 660 aaaatttatc cagcgcaaag ggacttttca
ggctagccgc cagccgggta atcagcttat 720 ccagcaacgt ttcgctggat
gttggcggca acgaatcact ggtgtaacga tggcgattca 780 gcaacatcac
caactgcccg aacagcaact cagccatttc gttagcaaac ggcacatgct 840
gactactttc atgctcaagc tgaccgataa cctgccgcgc ctgcgccatc cccatgctac
900 ctaagcgcca gtgtggttgc cctgcgctgg cgttaaatcc cggaatcgcc
ccctgccagt 960 caagattcag cttcagacgc tccgggcaat aaataatatt
ctgcaaaacc agatcgttaa 1020 cggaagcgta ggagtgttta tcgtcagcat
gaatgtaaaa gagatcgcca cgggtaatgc 1080 gataagggcg atcgttgagt
acatgcaggc cattaccgcg ccagacaatc accagctcac 1140 aaaaatcatg
tgtatgttca gcaaagacat cttgcggata acggtcagcc acagcgactg 1200
cctgctggtc gctggcaaaa aaatcatctt tgagaagttt taactgatgc gccaccgtgg
1260 ctacctcggc cagagaacga agttgattat tcgcaatatg gcgtacaaat
acgttgagaa 1320 gattcgcgtt attgcagaaa gccatcccgt ccctggcgaa
tatcacgcgg tgaccagtta 1380 aactctcggc gaaaaagcgt cgaaaagtgg
ttactgtcgc tgaatccaca gcgataggcg 1440 atgtcagtaa cgctggcctc
gctgtggcgt agcagatgtc gggctttcat cagtcgcagg 1500 cggttcaggt
atcgctgagg cgtcagtccc gtttgctgct taagctgccg atgtagcgta 1560
cgcagtgaaa gagaaaattg atccgccacg gcatcccaat tcacctcatc ggcaaaatgg
1620 tcctccagcc aggccagaag caagttgaga cgtgatgcgc tgttttccag
gttctcctgc 1680 aaactgcttt tacgcagcaa gagcagtaat tgcataaaca
agatctcgcg actggcggtc 1740 gagggtaaat cattttcccc ttcctgctgt
tccatctgtg caaccagctg tcgcacctgc 1800 tgcaatacgc tgtggttaac
gcgccagtga gacggatact gcccatccag ctcttgtggc 1860 agcaactgat
tcagcccggc gagaaactga aatcgatccg gcgagcgata cagcacattg 1920
gtcagacaca gattatcggt atgttcatac agatgccgat catgatcgcg tacgaaacag
1980 accgtgccac cggtgatggt atagggctgc ccattaaaca catgaatacc
cgtgccatgt 2040 tcgacaatca caatttcatg aaaatcatga tgatgttcag
gaaaatccgc ctgcgggagc 2100 cggggttcta tcgccacgga cgcgttacca
gacggaaaaa aatccacact atgtaatacg 2160 gtcatactgg cctcctgatg
tcgtcaacac ggcgaaatag taatcacgag gtcaggttct 2220 taccttaaat
tttcgacgga aaaccacgta aaaaacgtcg atttttcaag atacagcgtg 2280
aattttcagg aaatgcggtg agcatcacat caccacaatt cagcaaattg tgaacatcat
2340 cacgttcatc tttccctggt tgccaatggc ccattttcct gtcagtaacg
agaaggtcgc 2400 gaattcaggc gctttttaga ctggtcgtaa tgaaattcag
caggatcaca ttctgcaggt 2460 cgactctaga ggatccccgg gtaccgagct
cgaattcgta atcatggtca tagctgtttc 2520 ctgtgtgaaa ttgttatccg
ctcacaattc cacacaacat acgagccgga agcataaagt 2580 gtaaagcctg
gggtgcctaa tgagtgagct aactcacatt aattgcgttg cgctcactgc 2640
ccgctttcca gtcgggaaac ctgtcgtgcc agctgcatta atgaatcggc caacgcgcgg
2700 ggagaggcgg tttgcgtatt gggcgctctt ccgcttcctc gctcactgac
tcgctgcgct 2760 cggtcgttcg gctgcggcga gcggtatcag ctcactcaaa
ggcggtaata cggttatcca 2820 cagaatcagg ggataacgca ggaaagaaca
tgtgagcaaa aggccagcaa aaggccagga 2880 accgtaaaaa ggccgcgttg
ctggcgtttt tccataggct ccgcccccct gacgagcatc 2940 acaaaaatcg
acgctcaagt cagaggtggc gaaacccgac aggactataa agataccagg 3000
cgtttccccc tggaagctcc ctcgtgcgct ctcctgttcc gaccctgccg cttaccggat
3060 acctgtccgc ctttctccct tcgggaagcg tggcgctttc tcatagctca
cgctgtaggt 3120 atctcagttc ggtgtaggtc gttcgctcca agctgggctg
tgtgcacgaa ccccccgttc 3180 agcccgaccg ctgcgcctta tccggtaact
atcgtcttga gtccaacccg gtaagacacg 3240 acttatcgcc actggcagca
gccactggta acaggattag cagagcgagg tatgtaggcg 3300 gtgctacaga
gttcttgaag tggtggccta actacggcta cactagaagg acagtatttg 3360
gtatctgcgc tctgctgaag ccagttacct tcggaaaaag agttggtagc tcttgatccg
3420 gcaaacaaac caccgctggt agcggtggtt tttttgtttg caagcagcag
attacgcgca 3480 gaaaaaaagg atctcaagaa gatcctttga tcttttctac
ggggtctgac gctcagtgga 3540 acgaaaactc acgttaaggg attttggtca
tgagattatc aaaaaggatc ttcacctaga 3600 tccttttaaa ttaaaaatga
agttttaaat caatctaaag tatatatgag taaacttggt 3660 ctgacagtta
ccaatgctta atcagtgagg cacctatctc agcgatctgt ctatttcgtt 3720
catccatagt tgcctgactc cccgtcgtgt agataactac gatacgggag ggcttaccat
3780 ctggccccag tgctgcaatg ataccgcgag acccacgctc accggctcca
gatttatcag 3840 caataaacca gccagccgga agggccgagc gcagaagtgg
tcctgcaact ttatccgcct 3900 ccatccagtc tattaattgt tgccgggaag
ctagagtaag tagttcgcca gttaatagtt 3960 tgcgcaacgt tgttgccatt
gctacaggca tcgtggtgtc acgctcgtcg tttggtatgg 4020 cttcattcag
ctccggttcc caacgatcaa ggcgagttac
atgatccccc atgttgtgca 4080 aaaaagcggt tagctccttc ggtcctccga
tcgttgtcag aagtaagttg gccgcagtgt 4140 tatcactcat ggttatggca
gcactgcata attctcttac tgtcatgcca tccgtaagat 4200 gcttttctgt
gactggtgag tactcaacca agtcattctg agaatagtgt atgcggcgac 4260
cgagttgctc ttgcccggcg tcaatacggg ataataccgc gccacatagc agaactttaa
4320 aagtgctcat cattggaaaa cgttcttcgg ggcgaaaact ctcaaggatc
ttaccgctgt 4380 tgagatccag ttcgatgtaa cccactcgtg cacccaactg
atcttcagca tcttttactt 4440 tcaccagcgt ttctgggtga gcaaaaacag
gaaggcaaaa tgccgcaaaa aagggaataa 4500 gggcgacacg gaaatgttga
atactcatac tcttcctttt tcaatattat tgaagcattt 4560 atcagggtta
ttgtctcatg agcggataca tatttgaatg tatttagaaa aataaacaaa 4620
taggggttcc gcgcacattt ccccgaaaag tgccacctga cgtctaagaa accattatta
4680 tcatgacatt aacctataaa aataggcgta tcacgaggcc ctttcgtc 4728 7
1440 DNA E. coli 7 gaattcaggc gctttttaga ctggtcgtaa tgaaattcag
caggatcaca ttctgcagat 60 gcctgttctg gaaaaccggg ctgctcaggg
cgatattact gcacccggcg gtgctcgccg 120 tttaacgggt gatcagactg
ccgctctgcg tgattctctt agcgataaac ctgcaaaaaa 180 tattattttg
ctgattggcg atgggatggg ggactcggaa attactgccg cacgtaatta 240
tgccgaaggt gcgggcggct tttttaaagg tatagatgcc ttaccgctta ccgggcaata
300 cactcactat gcgctgaata aaaaaaccgg caaaccggac tacgtcaccg
actcggctgc 360 atcagcaacc gcctggtcaa ccggtgtcaa aacctataac
ggcgcgctgg gcgtcgatat 420 tcacgaaaaa gatcacccaa cgattctgga
aatggcaaaa gccgcaggtc tggcgaccgg 480 taacgtttct accgcagagt
tgcaggatgc cacgcccgct gcgctggtgg cacatgtgac 540 ctcgcgcaaa
tgctacggtc cgagcgcgac cagtgaaaaa tgtccgggta acgctctgga 600
aaaaggcgga aaaggatcga ttaccgaaca gctgcttaac gctcgtgccg acgttacgct
660 tggcggcggc gcaaaaacct ttgctgaaac ggcaaccgct ggtgaatggc
agggaaaaac 720 gctgcgtgaa caggcacagg cgcgtggtta tcagttggtg
agcgatgctg cctcactgaa 780 ttcggtgacg gaagcgaatc agcaaaaacc
cctgcttggc ctgtttgctg acggcaatat 840 gccagtgcgc tggctaggac
cgaaagcaac gtaccatggc aatatcgata agcccgcagt 900 cacctgtacg
ccaaatccgc aacgtaatga cagtgtacca accctggcgc agatgaccga 960
caaagccatt gaattgttga gtaaaaatga gaaaggcttt ttcctgcaag ttgaaggtgc
1020 gtcaatcgat aaacaggatc atgctgcgaa tccttgtggg caaattggcg
agacggtcga 1080 tctcgatgaa gccgtacaac gggcgctgga attcgctaaa
aaggagggta acacgctggt 1140 catagtcacc gctgatcacg cccacgccag
ccagattgtt gcgccggata ccaaagctcc 1200 gggcctcacc caggcgctaa
ataccaaaga tggcgcagtg atggtgatga gttacgggaa 1260 ctccgaagag
gattcacaag aacataccgg cagtcagttg cgtattgcgg cgtatggccc 1320
gcatgccgcc aatgttgttg gactgaccga ccagaccgat ctcttctaca ccatgaaagc
1380 cgctctgggg ctgaaataat aatctagagg atccccgggt accgagctcg
aattcgtaat 1440 8 1560 DNA E. coli 8 gaattcaggc gctttttaga
ctggtcgtaa tgaaattcag caggatcaca ttctgcagat 60 gtcacggccg
agacttatag tcgctttgtt tttatttttt aatgtatttg tacatggaga 120
aaataaagtg aaacaaagca ctattgcact ggcactctta ccgttactgt ttacccctgt
180 gacaaaagcc cggacaccag aaatgcctgt tctggaaaac cgggctgctc
agggcgatat 240 tactgcaccc ggcggtgctc gccgtttaac gggtgatcag
actgccgctc tgcgtgattc 300 tcttagcgat aaacctgcaa aaaatattat
tttgctgatt ggcgatggga tgggggactc 360 ggaaattact gccgcacgta
attatgccga aggtgcgggc ggctttttta aaggtataga 420 tgccttaccg
cttaccgggc aatacactca ctatgcgctg aataaaaaaa ccggcaaacc 480
ggactacgtc accgactcgg ctgcatcagc aaccgcctgg tcaaccggtg tcaaaaccta
540 taacggcgcg ctgggcgtcg atattcacga aaaagatcac ccaacgattc
tggaaatggc 600 aaaagccgca ggtctggcga ccggtaacgt ttctaccgca
gagttgcagg atgccacgcc 660 cgctgcgctg gtggcacatg tgacctcgcg
caaatgctac ggtccgagcg cgaccagtga 720 aaaatgtccg ggtaacgctc
tggaaaaagg cggaaaagga tcgattaccg aacagctgct 780 taacgctcgt
gccgacgtta cgcttggcgg cggcgcaaaa acctttgctg aaacggcaac 840
cgctggtgaa tggcagggaa aaacgctgcg tgaacaggca caggcgcgtg gttatcagtt
900 ggtgagcgat gctgcctcac tgaattcggt gacggaagcg aatcagcaaa
aacccctgct 960 tggcctgttt gctgacggca atatgccagt gcgctggcta
ggaccgaaag caacgtacca 1020 tggcaatatc gataagcccg cagtcacctg
tacgccaaat ccgcaacgta atgacagtgt 1080 accaaccctg gcgcagatga
ccgacaaagc cattgaattg ttgagtaaaa atgagaaagg 1140 ctttttcctg
caagttgaag gtgcgtcaat cgataaacag gatcatgctg cgaatccttg 1200
tgggcaaatt ggcgagacgg tcgatctcga tgaagccgta caacgggcgc tggaattcgc
1260 taaaaaggag ggtaacacgc tggtcatagt caccgctgat cacgcccacg
ccagccagat 1320 tgttgcgccg gataccaaag ctccgggcct cacccaggcg
ctaaatacca aagatggcgc 1380 agtgatggtg atgagttacg ggaactccga
agaggattca caagaacata ccggcagtca 1440 gttgcgtatt gcggcgtatg
gcccgcatgc cgccaatgtt gttggactga ccgaccagac 1500 cgatctcttc
tacaccatga aagccgctct ggggctgaaa taatctagag gatccccggg 1560 9 1500
DNA Artificial Sequence Gene encoding a fusion protein 9 gaattcaggc
gctttttaga ctggtcgtaa tgaaattcag caggatcaca ttctgcagat 60
gaacttgggg aatcgactgt ttattctgat agcggtctta cttcccctcg cagtattact
120 gctcatgcct gttctggaaa accgggctgc tcagggcgat attactgcac
ccggcggtgc 180 tcgccgttta acgggtgatc agactgccgc tctgcgtgat
tctcttagcg ataaacctgc 240 aaaaaatatt attttgctga ttggcgatgg
gatgggggac tcggaaatta ctgccgcacg 300 taattatgcc gaaggtgcgg
gcggcttttt taaaggtata gatgccttac cgcttaccgg 360 gcaatacact
cactatgcgc tgaataaaaa aaccggcaaa ccggactacg tcaccgactc 420
ggctgcatca gcaaccgcct ggtcaaccgg tgtcaaaacc tataacggcg cgctgggcgt
480 cgatattcac gaaaaagatc acccaacgat tctggaaatg gcaaaagccg
caggtctggc 540 gaccggtaac gtttctaccg cagagttgca ggatgccacg
cccgctgcgc tggtggcaca 600 tgtgacctcg cgcaaatgct acggtccgag
cgcgaccagt gaaaaatgtc cgggtaacgc 660 tctggaaaaa ggcggaaaag
gatcgattac cgaacagctg cttaacgctc gtgccgacgt 720 tacgcttggc
ggcggcgcaa aaacctttgc tgaaacggca accgctggtg aatggcaggg 780
aaaaacgctg cgtgaacagg cacaggcgcg tggttatcag ttggtgagcg atgctgcctc
840 actgaattcg gtgacggaag cgaatcagca aaaacccctg cttggcctgt
ttgctgacgg 900 caatatgcca gtgcgctggc taggaccgaa agcaacgtac
catggcaata tcgataagcc 960 cgcagtcacc tgtacgccaa atccgcaacg
taatgacagt gtaccaaccc tggcgcagat 1020 gaccgacaaa gccattgaat
tgttgagtaa aaatgagaaa ggctttttcc tgcaagttga 1080 aggtgcgtca
atcgataaac aggatcatgc tgcgaatcct tgtgggcaaa ttggcgagac 1140
ggtcgatctc gatgaagccg tacaacgggc gctggaattc gctaaaaagg agggtaacac
1200 gctggtcata gtcaccgctg atcacgccca cgccagccag attgttgcgc
cggataccaa 1260 agctccgggc ctcacccagg cgctaaatac caaagatggc
gcagtgatgg tgatgagtta 1320 cgggaactcc gaagaggatt cacaagaaca
taccggcagt cagttgcgta ttgcggcgta 1380 tggcccgcat gccgccaatg
ttgttggact gaccgaccag accgatctct tctacaccat 1440 gaaagccgct
ctggggctga aataataatc tagaggatcc ccgggtaccg agctcgaatt 1500 10 3908
DNA Artificial Sequence Expression vector 10 tcgcgcgttt cggtgatgac
ggtgaaaacc tctgacacat gcagctcccg gagacggtca 60 cagcttgtct
gtaagcggat gccgggagca gacaagcccg tcagggcgcg tcagcgggtg 120
ttggcgggtg tcggggctgg cttaactatg cggcatcaga gcagattgta ctgagagtgc
180 accatatgcg gtgtgaaata ccgcacagat gcgtaaggag aaaataccgc
atcaggcgcc 240 attcgccatt caggctgcgc aactgttggg aagggcgatc
ggtgcgggcc tcttcgctat 300 tacgccagct ggcgaaaggg ggatgtgctg
caaggcgatt aagttgggta acgccagggt 360 tgctcgcctg ctgcgagctg
ggtaagcgga caaattctca ccgtctccgg tggtggggta 420 caggagctca
attaatacac taacggaccg gtaaacaacc gtgcgtgttg tttaccggga 480
taaactcatc aacgtctctg ctaaataact ggcagccaaa tcacggctat tggttaacca
540 atttcagagt gaaaagtata cgaatagagt gtgccttcgc actattcaac
agcaatgata 600 ggcgctcacc tgacaacgcg gtaaactagt tattcacgct
aactataatg gtttaatgat 660 ggataacatg cagactgaag cacaaccgac
acggacccgg atcctcaatg ctgccagaga 720 gattttttca gaaaatggat
ttcacagtgc ctcgatgaaa gccatctgta aatcttgcgc 780 cattagtccc
gggacgctct atcaccattt catctccaaa gaagccttga ttcaggcgat 840
tatcttacag gaccaggaga gggcgctggc ccgtttccgg gaaccgattg aagggattca
900 tttcgttgac tatatggtcg agtccattgt ctctctcacc catgaagcct
ttggacaacg 960 ggcgctggtg gttgaaatta tggcggaagg gatgcgtaac
ccacaggtcg ccgccatgct 1020 taaaaataag catatgacga tcacggaatt
tgttgcccag cggatgcgtg atgcccagca 1080 aaaaggcgag ataagcccag
acatcaacac ggcaatgact tcacgtttac tgctggatct 1140 gacctacggt
gtactggccg atatcgaagc ggaagacctg gcgcgtgaag cgtcgtttgc 1200
tcagggatta cgcgcgatga ttggcggtat cttaaccgca tcctgattct ctctcttttt
1260 cggcgggctg gtgataactg tgcccgcgtt tcatatcgta atttctctgt
gcaaaaatta 1320 tccttcccgg cttcggagaa ttccccccaa aatattcact
gtagccatat gtcatgagag 1380 tttatcgttc ccaatacgct cgaacgaacg
ttcggttgct tattttatgg cttctgtcaa 1440 cgctgtttta aagattaatg
cgatctatat cacgctgtgg gtattgcagt ttttggtttt 1500 ttgatcgcgg
tgtcagttct ttttatttcc atttctcttc catgggtttc tcacagataa 1560
ctgtgtgcaa cacagaattg gttaactaat cagattaaag gttgaccagt attattatct
1620 taatgaggag tcctgcaggt cgactctaga ggatccccgg gtaccgagct
cgaattcgta 1680 atcatggtca tagctgtttc ctgtgtgaaa ttgttatccg
ctcacaattc cacacaacat 1740 acgagccgga agcataaagt gtaaagcctg
gggtgcctaa tgagtgagct aactcacatt 1800 aattgcgttg cgctcactgc
ccgctttcca gtcgggaaac ctgtcgtgcc agctgcatta 1860 atgaatcggc
caacgcgcgg ggagaggcgg tttgcgtatt gggcgctctt ccgcttcctc 1920
gctcactgac tcgctgcgct cggtcgttcg gctgcggcga gcggtatcag ctcactcaaa
1980 ggcggtaata cggttatcca cagaatcagg ggataacgca ggaaagaaca
tgtgagcaaa 2040 aggccagcaa aaggccagga accgtaaaaa ggccgcgttg
ctggcgtttt tccataggct 2100 ccgcccccct gacgagcatc acaaaaatcg
acgctcaagt cagaggtggc gaaacccgac 2160 aggactataa agataccagg
cgtttccccc tggaagctcc ctcgtgcgct ctcctgttcc 2220 gaccctgccg
cttaccggat acctgtccgc ctttctccct tcgggaagcg tggcgctttc 2280
tcatagctca cgctgtaggt atctcagttc ggtgtaggtc gttcgctcca agctgggctg
2340 tgtgcacgaa ccccccgttc agcccgaccg ctgcgcctta tccggtaact
atcgtcttga 2400 gtccaacccg gtaagacacg acttatcgcc actggcagca
gccactggta acaggattag 2460 cagagcgagg tatgtaggcg gtgctacaga
gttcttgaag tggtggccta actacggcta 2520 cactagaagg acagtatttg
gtatctgcgc tctgctgaag ccagttacct tcggaaaaag 2580 agttggtagc
tcttgatccg gcaaacaaac caccgctggt agcggtggtt tttttgtttg 2640
caagcagcag attacgcgca gaaaaaaagg atctcaagaa gatcctttga tcttttctac
2700 ggggtctgac gctcagtgga acgaaaactc acgttaaggg attttggtca
tgagattatc 2760 aaaaaggatc ttcacctaga tccttttaaa ttaaaaatga
agttttaaat caatctaaag 2820 tatatatgag taaacttggt ctgacagtta
ccaatgctta atcagtgagg cacctatctc 2880 agcgatctgt ctatttcgtt
catccatagt tgcctgactc cccgtcgtgt agataactac 2940 gatacgggag
ggcttaccat ctggccccag tgctgcaatg ataccgcgag acccacgctc 3000
accggctcca gatttatcag caataaacca gccagccgga agggccgagc gcagaagtgg
3060 tcctgcaact ttatccgcct ccatccagtc tattaattgt tgccgggaag
ctagagtaag 3120 tagttcgcca gttaatagtt tgcgcaacgt tgttgccatt
gctacaggca tcgtggtgtc 3180 acgctcgtcg tttggtatgg cttcattcag
ctccggttcc caacgatcaa ggcgagttac 3240 atgatccccc atgttgtgca
aaaaagcggt tagctccttc ggtcctccga tcgttgtcag 3300 aagtaagttg
gccgcagtgt tatcactcat ggttatggca gcactgcata attctcttac 3360
tgtcatgcca tccgtaagat gcttttctgt gactggtgag tactcaacca agtcattctg
3420 agaatagtgt atgcggcgac cgagttgctc ttgcccggcg tcaatacggg
ataataccgc 3480 gccacatagc agaactttaa aagtgctcat cattggaaaa
cgttcttcgg ggcgaaaact 3540 ctcaaggatc ttaccgctgt tgagatccag
ttcgatgtaa cccactcgtg cacccaactg 3600 atcttcagca tcttttactt
tcaccagcgt ttctgggtga gcaaaaacag gaaggcaaaa 3660 tgccgcaaaa
aagggaataa gggcgacacg gaaatgttga atactcatac tcttcctttt 3720
tcaatattat tgaagcattt atcagggtta ttgtctcatg agcggataca tatttgaatg
3780 tatttagaaa aataaacaaa taggggttcc gcgcacattt ccccgaaaag
tgccacctga 3840 cgtctaagaa accattatta tcatgacatt aacctataaa
aataggcgta tcacgaggcc 3900 ctttcgtc 3908 11 3872 DNA Artificial
Sequence Expression vector 11 tcgcgcgttt cggtgatgac ggtgaaaacc
tctgacacat gcagctcccg gagacggtca 60 cagcttgtct gtaagcggat
gccgggagca gacaagcccg tcagggcgcg tcagcgggtg 120 ttggcgggtg
tcggggctgg cttaactatg cggcatcaga gcagattgta ctgagagtgc 180
accatatgcg gtgtgaaata ccgcacagat gcgtaaggag aaaataccgc atcaggcgcc
240 attcgccatt caggctgcgc aactgttggg aagggcgatc ggtgcgggcc
tcttcgctat 300 tacgccagct ggcgaaaggg ggatgtgctg caaggcgatt
aagttgggta acgccagggt 360 tttcccagtc acgacgttgt aaaacgacgg
ccagtgccaa gcttttagcc gggaaacgtc 420 tggcggcgct gttggctaag
tttgcggtat tgttgcggcg acatgccgac atatttgccg 480 aacgtgctgt
aaaaacgact acttgaacga aagcctgccg tcagggcaat atcgagaata 540
cttttatcgg tatcgctcag taacgcgcga acgtggttga tgcgcatcgc ggtaatgtac
600 tgtttcatcg tcaattgcat gacccgctgg aatatcccca ttgcatagtt
ggcgttaagt 660 ttgacgtgct cagccacatc gttgatggtc agcgcctgat
catagttttc ggcaataaag 720 cccagcatct ggctaacata aaattgcgca
tggcgcgaga cgctgttttt gtgtgtgcgc 780 gaggttttat tgaccagaat
cggttcccag ccagagaggc taaatcgctt gagcatcagg 840 ccaatttcat
caatggcgag ctggcgaatt tgctcgttcg gactgtttaa ttcctgctgc 900
cagcggcgca cttcaaacgg gctaagttgc tgtgtggcca gtgatttgat caccatgccg
960 tgagtgacgt ggttaatcag gtctttatcc agcggccagg agagaaacag
atgcatcggc 1020 agattaaaaa tcgccatgct ctgacaggtt ccggtatctg
ttagttggtg cggtgtacag 1080 gcccagaaca gcgtgatatg accctgattg
atattcactt tttcattgtt gatcaggtat 1140 tccacatcgc catcgaaagg
cacattcact tcgacctgac catgccagtg gctggtgggc 1200 atgatatgcg
gtgcgcgaaa ctcaatctcc atccgctggt attccgaata cagcgacagc 1260
gggctgcggg tctgtttttc gtcgctgctg cacataaacg tatctgtatt catggatggc
1320 tctctttcct ggaatatcag aattatggca ggagtgaggg aggatgactg
cgagtgggag 1380 cacggttttc accctcttcc cagaggggcg aggggactct
ccgagtatca tgaggccgaa 1440 aactctgctt ttcaggtaat ttattcccat
aaactcagat ttactgctgc ttcacgcagg 1500 atctgagttt atgggaatgc
tcaacctgga agccggaggt tttctgcaga ttcgcctgcc 1560 atgatgaagt
tattcaagca agccaggaga tctggtaccc gggtcgactc tagaggatcc 1620
ccgggtaccg agctcgaatt cgtaatcatg gtcatagctg tttcctgtgt gaaattgtta
1680 tccgctcaca attccacaca acatacgagc cggaagcata aagtgtaaag
cctggggtgc 1740 ctaatgagtg agctaactca cattaattgc gttgcgctca
ctgcccgctt tccagtcggg 1800 aaacctgtcg tgccagctgc attaatgaat
cggccaacgc gcggggagag gcggtttgcg 1860 tattgggcgc tcttccgctt
cctcgctcac tgactcgctg cgctcggtcg ttcggctgcg 1920 gcgagcggta
tcagctcact caaaggcggt aatacggtta tccacagaat caggggataa 1980
cgcaggaaag aacatgtgag caaaaggcca gcaaaaggcc aggaaccgta aaaaggccgc
2040 gttgctggcg tttttccata ggctccgccc ccctgacgag catcacaaaa
atcgacgctc 2100 aagtcagagg tggcgaaacc cgacaggact ataaagatac
caggcgtttc cccctggaag 2160 ctccctcgtg cgctctcctg ttccgaccct
gccgcttacc ggatacctgt ccgcctttct 2220 cccttcggga agcgtggcgc
tttctcatag ctcacgctgt aggtatctca gttcggtgta 2280 ggtcgttcgc
tccaagctgg gctgtgtgca cgaacccccc gttcagcccg accgctgcgc 2340
cttatccggt aactatcgtc ttgagtccaa cccggtaaga cacgacttat cgccactggc
2400 agcagccact ggtaacagga ttagcagagc gaggtatgta ggcggtgcta
cagagttctt 2460 gaagtggtgg cctaactacg gctacactag aaggacagta
tttggtatct gcgctctgct 2520 gaagccagtt accttcggaa aaagagttgg
tagctcttga tccggcaaac aaaccaccgc 2580 tggtagcggt ggtttttttg
tttgcaagca gcagattacg cgcagaaaaa aaggatctca 2640 agaagatcct
ttgatctttt ctacggggtc tgacgctcag tggaacgaaa actcacgtta 2700
agggattttg gtcatgagat tatcaaaaag gatcttcacc tagatccttt taaattaaaa
2760 atgaagtttt aaatcaatct aaagtatata tgagtaaact tggtctgaca
gttaccaatg 2820 cttaatcagt gaggcaccta tctcagcgat ctgtctattt
cgttcatcca tagttgcctg 2880 actccccgtc gtgtagataa ctacgatacg
ggagggctta ccatctggcc ccagtgctgc 2940 aatgataccg cgagacccac
gctcaccggc tccagattta tcagcaataa accagccagc 3000 cggaagggcc
gagcgcagaa gtggtcctgc aactttatcc gcctccatcc agtctattaa 3060
ttgttgccgg gaagctagag taagtagttc gccagttaat agtttgcgca acgttgttgc
3120 cattgctaca ggcatcgtgg tgtcacgctc gtcgtttggt atggcttcat
tcagctccgg 3180 ttcccaacga tcaaggcgag ttacatgatc ccccatgttg
tgcaaaaaag cggttagctc 3240 cttcggtcct ccgatcgttg tcagaagtaa
gttggccgca gtgttatcac tcatggttat 3300 ggcagcactg cataattctc
ttactgtcat gccatccgta agatgctttt ctgtgactgg 3360 tgagtactca
accaagtcat tctgagaata gtgtatgcgg cgaccgagtt gctcttgccc 3420
ggcgtcaata cgggataata ccgcgccaca tagcagaact ttaaaagtgc tcatcattgg
3480 aaaacgttct tcggggcgaa aactctcaag gatcttaccg ctgttgagat
ccagttcgat 3540 gtaacccact cgtgcaccca actgatcttc agcatctttt
actttcacca gcgtttctgg 3600 gtgagcaaaa acaggaaggc aaaatgccgc
aaaaaaggga ataagggcga cacggaaatg 3660 ttgaatactc atactcttcc
tttttcaata ttattgaagc atttatcagg gttattgtct 3720 catgagcgga
tacatatttg aatgtattta gaaaaataaa caaatagggg ttccgcgcac 3780
atttccccga aaagtgccac ctgacgtcta agaaaccatt attatcatga cattaaccta
3840 taaaaatagg cgtatcacga ggccctttcg tc 3872 12 3934 DNA
Artificial Sequence Expression vector 12 tcgcgcgttt cggtgatgac
ggtgaaaacc tctgacacat gcagctcccg gagacggtca 60 cagcttgtct
gtaagcggat gccgggagca gacaagcccg tcagggcgcg tcagcgggtg 120
ttggcgggtg tcggggctgg cttaactatg cggcatcaga gcagattgta ctgagagtgc
180 accatatgcg gtgtgaaata ccgcacagat gcgtaaggag aaaataccgc
atcaggcgcc 240 attcgccatt caggctgcgc aactgttggg aagggcgatc
ggtgcgggcc tcttcgctat 300 tacgccagct ggcgaaaggg ggatgtgctg
caaggcgatt aagttgggta acgccagggt 360 tttcccagtc acgacgttgt
aaaacgacgg ccagtgccaa gcttcaagcc gtcaattgtc 420 tgattcgtta
ccaattatga caacttgacg gctacatcat tcactttttc ttcacaaccg 480
gcacggaact cgctcgggct ggccccggtg cattttttaa atacccgcga gaaatagagt
540 tgatcgtcaa aaccaacatt gcgaccgacg gtggcgatag gcatccgggt
ggtgctcaaa 600 agcagcttcg cctggctgat acgttggtcc tcgcgccagc
ttaagacgct aatccctaac 660 tgctggcgga aaagatgtga cagacgcgac
ggcgacaagc aaacatgctg tgcgacgctg 720 gcgatatcaa aattgctgtc
tgccaggtga tcgctgatgt actgacaagc ctcgcgtacc 780 cgattatcca
tcggtggatg gagcgactcg ttaatcgctt ccatgcgccg cagtaacaat 840
tgctcaagca gatttatcgc cagcagctcc gaatagcgcc cttccccttg cccggcgtta
900 atgatttgcc caaacaggtc gctgaaatgc ggctggtgcg cttcatccgg
gcgaaagaac 960 cccgtattgg caaatattga cggccagtta agccattcat
gccagtaggc gcgcggacga 1020 aagtaaaccc actggtgata ccattcgcga
gcctccggat gacgaccgta gtgatgaatc 1080 tctcctggcg ggaacagcaa
aatatcaccc ggtcggcaaa caaattctcg tccctgattt 1140 ttcaccaccc
cctgaccgcg aatggtgaga ttgagaatat aacctttcat tcccagcggt 1200
cggtcgataa aaaaatcgag ataaccgttg gcctcaatcg gcgttaaacc cgccaccaga
1260 tgggcattaa acgagtatcc cggcagcagg ggatcatttt gcgcttcagc
catacttttc 1320 atactcccgc cattcagaga agaaaccaat tgtccatatt
gcatcagaca ttgccgtcac 1380 tgcgtctttt actggctctt ctcgctaacc
aaaccggtaa ccccgcttat taaaagcatt 1440 ctgtaacaaa gcgggaccaa
agccatgaca aaaacgcgta acaaaagtgt ctataatcac 1500 ggcagaaaag
tccacattga ttatttgcac ggcgtcacac tttgctatgc catagcattt 1560
ttatccataa gattagcgga tcctacctga cgctttttat cgcaactctc tactgtttct
1620 ccatacccgt ttttttgggc tagcaggagg aattcaccct gcaggtcgac
tctagaggat 1680 ccccgggtac cgagctcgaa ttcgtaatca tggtcatagc
tgtttcctgt gtgaaattgt 1740 tatccgctca caattccaca caacatacga
gccggaagca taaagtgtaa agcctggggt 1800 gcctaatgag tgagctaact
cacattaatt gcgttgcgct cactgcccgc tttccagtcg 1860 ggaaacctgt
cgtgccagct gcattaatga atcggccaac gcgcggggag aggcggtttg 1920
cgtattgggc gctcttccgc ttcctcgctc actgactcgc tgcgctcggt cgttcggctg
1980 cggcgagcgg tatcagctca ctcaaaggcg gtaatacggt tatccacaga
atcaggggat 2040 aacgcaggaa agaacatgtg agcaaaaggc cagcaaaagg
ccaggaaccg taaaaaggcc 2100 gcgttgctgg cgtttttcca taggctccgc
ccccctgacg agcatcacaa aaatcgacgc 2160 tcaagtcaga ggtggcgaaa
cccgacagga ctataaagat accaggcgtt tccccctgga 2220 agctccctcg
tgcgctctcc tgttccgacc ctgccgctta ccggatacct gtccgccttt 2280
ctcccttcgg gaagcgtggc gctttctcat agctcacgct gtaggtatct cagttcggtg
2340 taggtcgttc gctccaagct gggctgtgtg cacgaacccc ccgttcagcc
cgaccgctgc 2400 gccttatccg gtaactatcg tcttgagtcc aacccggtaa
gacacgactt atcgccactg 2460 gcagcagcca ctggtaacag gattagcaga
gcgaggtatg taggcggtgc tacagagttc 2520 ttgaagtggt ggcctaacta
cggctacact agaaggacag tatttggtat ctgcgctctg 2580 ctgaagccag
ttaccttcgg aaaaagagtt ggtagctctt gatccggcaa acaaaccacc 2640
gctggtagcg gtggtttttt tgtttgcaag cagcagatta cgcgcagaaa aaaaggatct
2700 caagaagatc ctttgatctt ttctacgggg tctgacgctc agtggaacga
aaactcacgt 2760 taagggattt tggtcatgag attatcaaaa aggatcttca
cctagatcct tttaaattaa 2820 aaatgaagtt ttaaatcaat ctaaagtata
tatgagtaaa cttggtctga cagttaccaa 2880 tgcttaatca gtgaggcacc
tatctcagcg atctgtctat ttcgttcatc catagttgcc 2940 tgactccccg
tcgtgtagat aactacgata cgggagggct taccatctgg ccccagtgct 3000
gcaatgatac cgcgagaccc acgctcaccg gctccagatt tatcagcaat aaaccagcca
3060 gccggaaggg ccgagcgcag aagtggtcct gcaactttat ccgcctccat
ccagtctatt 3120 aattgttgcc gggaagctag agtaagtagt tcgccagtta
atagtttgcg caacgttgtt 3180 gccattgcta caggcatcgt ggtgtcacgc
tcgtcgtttg gtatggcttc attcagctcc 3240 ggttcccaac gatcaaggcg
agttacatga tcccccatgt tgtgcaaaaa agcggttagc 3300 tccttcggtc
ctccgatcgt tgtcagaagt aagttggccg cagtgttatc actcatggtt 3360
atggcagcac tgcataattc tcttactgtc atgccatccg taagatgctt ttctgtgact
3420 ggtgagtact caaccaagtc attctgagaa tagtgtatgc ggcgaccgag
ttgctcttgc 3480 ccggcgtcaa tacgggataa taccgcgcca catagcagaa
ctttaaaagt gctcatcatt 3540 ggaaaacgtt cttcggggcg aaaactctca
aggatcttac cgctgttgag atccagttcg 3600 atgtaaccca ctcgtgcacc
caactgatct tcagcatctt ttactttcac cagcgtttct 3660 gggtgagcaa
aaacaggaag gcaaaatgcc gcaaaaaagg gaataagggc gacacggaaa 3720
tgttgaatac tcatactctt cctttttcaa tattattgaa gcatttatca gggttattgt
3780 ctcatgagcg gatacatatt tgaatgtatt tagaaaaata aacaaatagg
ggttccgcgc 3840 acatttcccc gaaaagtgcc acctgacgtc taagaaacca
ttattatcat gacattaacc 3900 tataaaaata ggcgtatcac gaggcccttt cgtc
3934 13 5953 DNA Artificial Sequence Expression vector 13
tagttattaa tagtaatcaa ttacggggtc attagttcat agcccatata tggagttccg
60 cgttacataa cttacggtaa atggcccgcc tggctgaccg cccaacgacc
cccgcccatt 120 gacgtcaata atgacgtatg ttcccatagt aacgccaata
gggactttcc attgacgtca 180 atgggtggag tatttacggt aaactgccca
cttggcagta catcaagtgt atcatatgcc 240 aagtacgccc cctattgacg
tcaatgacgg taaatggccc gcctggcatt atgcccagta 300 catgacctta
tgggactttc ctacttggca gtacatctac gtattagtca tcgctattac 360
catggtgatg cggttttggc agtacatcaa tgggcgtgga tagcggtttg actcacgggg
420 atttccaagt ctccacccca ttgacgtcaa tgggagtttg ttttggcacc
aaaatcaacg 480 ggactttcca aaatgtcgta acaactccgc cccattgacg
caaatgggcg gtaggcgtgt 540 acggtgggag gtctatataa gcagagctgg
tttagtgaac cgtcagatcc gctagcgcta 600 gtcgagctgg acggcgacgt
aaacggccac aagttcagcg tgtccggcga gggcgagggc 660 gatgccacct
acggcaagct gaccctgaag ttcatctgca ccaccggcaa gctgcccgtg 720
ccctggccca ccctcgtgac caccctgacc tacggcgtgc agtgcttcag ccgctacccc
780 gaccacatga agcagcacga cttcttcaag tccgccatgc ccgaaggcta
cgtccaggag 840 cgcaccatct tcttcaagga cgacggcaac tacaagaccc
gcgccgaggt gaagttcgag 900 ggcgacaccc tggtgaaccg catcgagctg
aagggcatcg acttcaagga ggacggcaac 960 atcctggggc acaagctgga
gtacaactac aacagccaca acgtctatat catggccgac 1020 aagcagaaga
acggcatcaa ggtgaacttc aagatccgcc acaacatcga ggacggcagc 1080
gtgcagctcg ccgaccacta ccagcagaac acccccatcg gcgacggccc cgtgctgctg
1140 cccgacaacc actacctgag cacccagtcc gccctgagca aagaccccaa
cgagaagcgc 1200 gatcacatgg tcctgctgga gttcgtgacc gccgccggga
tcactctcgg catggacgag 1260 ctgtacaagt ccggactcag atctcgagct
taataacaag ccgtcaattg tctgattcgt 1320 taccaattat gacaacttga
cggctacatc attcactttt tcttcacaac cggcacggaa 1380 ctcgctcggg
ctggccccgg tgcatttttt aaatacccgc gagaaataga gttgatcgtc 1440
aaaaccaaca ttgcgaccga cggtggcgat aggcatccgg gtggtgctca aaagcagctt
1500 cgcctggctg atacgttggt cctcgcgcca gcttaagacg ctaatcccta
actgctggcg 1560 gaaaagatgt gacagacgcg acggcgacaa gcaaacatgc
tgtgcgacgc tggcgatatc 1620 aaaattgctg tctgccaggt gatcgctgat
gtactgacaa gcctcgcgta cccgattatc 1680 catcggtgga tggagcgact
cgttaatcgc ttccatgcgc cgcagtaaca attgctcaag 1740 cagatttatc
gccagcagct ccgaatagcg cccttcccct tgcccggcgt taatgatttg 1800
cccaaacagg tcgctgaaat gcggctggtg cgcttcatcc gggcgaaaga accccgtatt
1860 ggcaaatatt gacggccagt taagccattc atgccagtag gcgcgcggac
gaaagtaaac 1920 ccactggtga taccattcgc gagcctccgg atgacgaccg
tagtgatgaa tctctcctgg 1980 cgggaacagc aaaatatcac ccggtcggca
aacaaattct cgtccctgat ttttcaccac 2040 cccctgaccg cgaatggtga
gattgagaat ataacctttc attcccagcg gtcggtcgat 2100 aaaaaaatcg
agataaccgt tggcctcaat cggcgttaaa cccgccacca gatgggcatt 2160
aaacgagtat cccggcagca ggggatcatt ttgcgcttca gccatacttt tcatactccc
2220 gccattcaga gaagaaacca attgtccata ttgcatcaga cattgccgtc
actgcgtctt 2280 ttactggctc ttctcgctaa ccaaaccggt aaccccgctt
attaaaagca ttctgtaaca 2340 aagcgggacc aaagccatga caaaaacgcg
taacaaaagt gtctataatc acggcagaaa 2400 agtccacatt gattatttgc
acggcgtcac actttgctat gccatagcat ttttatccat 2460 aagattagcg
gatcctacct gacgcttttt atcgcaactc tctactgttt ctccataccc 2520
gtttttttgg gctagcagga ggaattcacc atggtacccg gggatcctct agagtcgacc
2580 tgcaggcatg caagcttggc ccgcgggccc gggatccacc ggatctagat
aactgatcat 2640 aatcagccat accacatttg tagaggtttt acttgcttta
aaaaacctcc cacacctccc 2700 cctgaacctg aaacataaaa tgaatgcaat
tgttgttgtt aacttgttta ttgcagctta 2760 taatggttac aaataaagca
atagcatcac aaatttcaca aataaagcat ttttttcact 2820 gcattctagt
tgtggtttgt ccaaactcat caatgtatct taacgcgtaa attgtaagcg 2880
ttaatatttt gttaaaattc gcgttaaatt tttgttaaat cagctcattt tttaaccaat
2940 aggccgaaat cggcaaaatc ccttataaat caaaagaata gaccgagata
gggttgagtg 3000 ttgttccagt ttggaacaag agtccactat taaagaacgt
ggactccaac gtcaaagggc 3060 gaaaaaccgt ctatcagggc gatggcccac
tacgtgaacc atcaccctaa tcaagttttt 3120 tggggtcgag gtgccgtaaa
gcactaaatc ggaaccctaa agggagcccc cgatttagag 3180 cttgacgggg
aaagccggcg aacgtggcga gaaaggaagg gaagaaagcg aaaggagcgg 3240
gcgctagggc gctggcaagt gtagcggtca cgctgcgcgt aaccaccaca cccgccgcgc
3300 ttaatgcgcc gctacagggc gcgtcaggtg gcacttttcg gggaaatgtg
cgcggaaccc 3360 ctatttgttt atttttctaa atacattcaa atatgtatcc
gctcatgaga caataaccct 3420 gataaatgct tcaataatat tgaaaaagga
agagtcctga ggcggaaaga accagctgtg 3480 gaatgtgtgt cagttagggt
gtggaaagtc cccaggctcc ccagcaggca gaagtatgca 3540 aagcatgcat
ctcaattagt cagcaaccag gtgtggaaag tccccaggct ccccagcagg 3600
cagaagtatg caaagcatgc atctcaatta gtcagcaacc atagtcccgc ccctaactcc
3660 gcccatcccg cccctaactc cgcccagttc cgcccattct ccgccccatg
gctgactaat 3720 tttttttatt tatgcagagg ccgaggccgc ctcggcctct
gagctattcc agaagtagtg 3780 aggaggcttt tttggaggcc taggcttttg
caaagatcga tcaagagaca ggatgaggat 3840 cgtttcgcat gattgaacaa
gatggattgc acgcaggttc tccggccgct tgggtggaga 3900 ggctattcgg
ctatgactgg gcacaacaga caatcggctg ctctgatgcc gccgtgttcc 3960
ggctgtcagc gcaggggcgc ccggttcttt ttgtcaagac cgacctgtcc ggtgccctga
4020 atgaactgca agacgaggca gcgcggctat cgtggctggc cacgacgggc
gttccttgcg 4080 cagctgtgct cgacgttgtc actgaagcgg gaagggactg
gctgctattg ggcgaagtgc 4140 cggggcagga tctcctgtca tctcaccttg
ctcctgccga gaaagtatcc atcatggctg 4200 atgcaatgcg gcggctgcat
acgcttgatc cggctacctg cccattcgac caccaagcga 4260 aacatcgcat
cgagcgagca cgtactcgga tggaagccgg tcttgtcgat caggatgatc 4320
tggacgaaga gcatcagggg ctcgcgccag ccgaactgtt cgccaggctc aaggcgagca
4380 tgcccgacgg cgaggatctc gtcgtgaccc atggcgatgc ctgcttgccg
aatatcatgg 4440 tggaaaatgg ccgcttttct ggattcatcg actgtggccg
gctgggtgtg gcggaccgct 4500 atcaggacat agcgttggct acccgtgata
ttgctgaaga gcttggcggc gaatgggctg 4560 accgcttcct cgtgctttac
ggtatcgccg ctcccgattc gcagcgcatc gccttctatc 4620 gccttcttga
cgagttcttc tgagcgggac tctggggttc gaaatgaccg accaagcgac 4680
gcccaacctg ccatcacgag atttcgattc caccgccgcc ttctatgaaa ggttgggctt
4740 cggaatcgtt ttccgggacg ccggctggat gatcctccag cgcggggatc
tcatgctgga 4800 gttcttcgcc caccctaggg ggaggctaac tgaaacacgg
aaggagacaa taccggaagg 4860 aacccgcgct atgacggcaa taaaaagaca
gaataaaacg cacggtgttg ggtcgtttgt 4920 tcataaacgc ggggttcggt
cccagggctg gcactctgtc gataccccac cgagacccca 4980 ttggggccaa
tacgcccgcg tttcttcctt ttccccaccc caccccccaa gttcgggtga 5040
aggcccaggg ctcgcagcca acgtcggggc ggcaggccct gccatagcct caggttactc
5100 atatatactt tagattgatt taaaacttca tttttaattt aaaaggatct
aggtgaagat 5160 cctttttgat aatctcatga ccaaaatccc ttaacgtgag
ttttcgttcc actgagcgtc 5220 agaccccgta gaaaagatca aaggatcttc
ttgagatcct ttttttctgc gcgtaatctg 5280 ctgcttgcaa acaaaaaaac
caccgctacc agcggtggtt tgtttgccgg atcaagagct 5340 accaactctt
tttccgaagg taactggctt cagcagagcg cagataccaa atactgtcct 5400
tctagtgtag ccgtagttag gccaccactt caagaactct gtagcaccgc ctacatacct
5460 cgctctgcta atcctgttac cagtggctgc tgccagtggc gataagtcgt
gtcttaccgg 5520 gttggactca agacgatagt taccggataa ggcgcagcgg
tcgggctgaa cggggggttc 5580 gtgcacacag cccagcttgg agcgaacgac
ctacaccgaa ctgagatacc tacagcgtga 5640 gctatgagaa agcgccacgc
ttcccgaagg gagaaaggcg gacaggtatc cggtaagcgg 5700 cagggtcgga
acaggagagc gcacgaggga gcttccaggg ggaaacgcct ggtatcttta 5760
tagtcctgtc gggtttcgcc acctctgact tgagcgtcga tttttgtgat gctcgtcagg
5820 ggggcggagc ctatggaaaa acgccagcaa cgcggccttt ttacggttcc
tggccttttg 5880 ctggcctttt gctcacatgt tctttcctgc gttatcccct
gattctgtgg ataaccgtat 5940 taccgccatg cat 5953 14 1380 DNA Rat 14
gaattcaggc gctttttaga ctggtcgtaa tgaaattcag caggatcaca ttctgcaggt
60 cgacatggca accacgcacg cgcagggcca cccgccagtc ttggggaatg
atactctccg 120 ggaacattat gattacgtgg ggaagctggc aggcaggctg
cgggatcccc ctgagggtag 180 caccctcatc accaccatcc tcttcttggt
cacctgtagc ttcatcgtct tggagaacct 240 gatggttttg attgccatct
ggaaaaacaa taaatttcat aaccgcatgt actttttcat 300 cggcaacttg
gctctctgcg acctgctggc cggcatagcc tacaaggtca acattctgat 360
gtccggtagg aagacgttca gcctgtctcc aacagtgtgg ttcctcaggg agggcagtat
420 gttcgtagcc ctgggcgcat ccacatgcag cttattggcc attgccattg
agcggcacct 480 gaccatgatc aagatgaggc cgtacgacgc caacaagaag
caccgcgtgt tccttctgat 540 tgggatgtgc tggctaattg ccttctcgct
gggtgccctg cccatcctgg gctggaactg 600 cctggaaaac tttcccgact
gctctaccat cttgcccctc tactccaaga aatacattgc 660 ctttctcatc
agcatcttca tagccattct ggtgaccatc gtcatcttgt acgcgcgcat 720
ctacttcctg gtcaagtcca gcagccgcag ggtggccaac cacaactccg agagatccat
780 ggcccttctg cggaccgtag tgatcgtggt gagcgtgttc atcgcctgtt
ggtcccccct 840 tttcatcctc ttcctcatcg atgtggcctg cagggcgaag
gagtgctcca tcctcttcaa 900 gagtcagtgg ttcatcatgc tggctgtcct
caactcggcc atgaaccctg tcatctacac 960 gctggccagc aaagagatgc
ggcgtgcttt cttccggttg gtgtgcggct gtctggtcaa 1020 gggcaagggg
acccaggcct ccccgatgca gcctgctctt gacccgagca gaagtaaatc 1080
aagctccagt aacaacagca gcagccactc tccaaaggtc aaggaagacc tgccccatgt
1140 ggctacctct tcctgcgtta ctgacaaaac gaggtcgctt cagaatgggg
tcctctgcaa 1200 gaagggcaat tctgcagata tccagcacag tggcggccgc
tcgagtctag agggcccgcg 1260 gttcgaaggt aagcctatcc ctaaccctct
cctcggtctc gattctacgc gtaccggtca 1320 tcatcaccat caccattgat
aaggtaccga gctcgaattc gtaatcatgg tcatagctgt 1380 15 1320 DNA Homo
sapien 15 gaattcaggc gctttttaga ctggtcgtaa tgaaattcag caggatcaca
ttctgcaggt 60 cgacatgggg caacccggga acggcagcgc cttcttgctg
gcacccaatg gaagccatgc 120 gccggaccac gacgtcacgc agcaaaggga
cgaggtgtgg gtggtgggca tgggcatcgt 180 catgtctctc atcgtcctgg
ccatcgtgtt tggcaatgtg ctggtcatca cagccattgc 240 caagttcgag
cgtctgcaga cggtcaccaa ctacttcatc acttcactgg cctgtgctga 300
tctggtcatg ggcctagcag tggtgccctt tggggccgcc catattctta tgaaaatgtg
360 gacttttggc aacttctggt gcgagttttg gacttccatt gatgtgctgt
gcgtcacggc 420 cagcattgag accctgtgcg tgatcgcagt ggatcgctac
tttgccatta cttcaccttt 480 caagtaccag agcctgctga ccaagaataa
ggcccgggtg atcattctga tggtgtggat 540 tgtgtcaggc cttayctcct
tcttgcccat tcagatgcac tggtacaggg ccacccacca 600 ggaagccatc
aactgctatg ccaatgagac ctgctgtgac ttcttcacga accaagccta 660
tgccattgcc tcttccatcg tgtccttcta cgttcccctg gtgatcatgg tcttcgtcta
720 ctccagggtc tttcaggagg ccaaaaggca gctccagaag attgacaaat
ctgagggccg 780 cttccatgtc cagaacctta gccaggtgga gcaggatggg
cggacggggc atggactccg 840 cagatcttcc aagttctgct tgaaggagca
caaagccctc aagacgttag gcatcatcat 900 gggcactttc accctctgct
ggctgccctt cttcatcgtt aacattgtgc atgtgatcca 960 ggataacctc
atccgtaagg aagtttacat cctcctaaat tggataggct atgtcaattc 1020
tggtttcaat ccccttatct actgccggag cccagatttc aggattgcct tccaggagct
1080 tctgtgcctg cgcaggtctt ctttgaaggc ctatggcaat ggctactcca
gcaacggcaa 1140 cacaggggag cagagtggat atcacgtgga acaggagaaa
gaaaataaac tgctgtgtga 1200 agacctccca ggcacggaag actttgtggg
ccatcaaggt actgtgccta gcgataacat 1260 tgattcacaa gggaggaatt
gtagtacaaa tgactcactg ctataataag gatccccggg 1320 16 52 DNA
Artificial Sequence Cloning primer 16 aattggtacc tcaatgatga
tgatgatgat gcttgcagag gaccccattc tg 52 17 1320 DNA Homo sapien 17
tcgcaactct ctactgtttc tccatacccg tttttttggg ctagcaggag gaattcacca
60 tggatagtgt gtgtccccaa ggaaaatata tccaccctca aaataattcg
atttgctgta 120 ccaagtgcca caaaggaacc tacttgtaca atgactgtcc
aggcccgggg caggatacgg 180 actgcaggga gtgtgagagc ggctccttca
ccgcttcaga aaaccacctc agacactgcc 240 tcagctgctc caaatgccga
aaggaaatgg gtcaggtgga gatctcttct tgcacagtgg 300 accgggacac
cgtgtgtggc tgcaggaaga accagtaccg gcattattgg agtgaaaacc 360
ttttccagtg cttcaattgc agcctctgcc tcaatgggac cgtgcacctc tcctgccagg
420 agaaacagaa caccgtgtgc acctgccatg caggtttctt tctaagagaa
aacgagtgtg 480 tctcctgtag taactgtaag aaaagcctgg agtgcacgaa
gttgtgccta ccccagattg 540 agaatgttaa gggcactgag gactcaggca
ccacagtgct gttgcccctg gtcattttct 600 ttggtctttg ccttttatcc
ctcctcttca ttggtttaat gtatcgctac caacggtgga 660 agtccaagct
ctactccatt gtttgtggga aatcgacacc tgaaaaagag ggggagcttg 720
aaggaactac tactaagccc ctggccccaa acccaagctt cagtcccact ccaggcttca
780 cccccaccct gggcttcagt cccgtgccca gttccacctt cacctccagc
tccacctata 840 cccccggtga ctgtcccaac tttgcggctc cccgcagaga
ggtggcacca ccctatcagg 900 gggctgaccc catccttgcg acagccctcg
cctccgaccc catccccaac ccccttcaga 960 agtgggagga cagcgcccac
aagccacaga gcctagacac tgatgacccc gcgacgctgt 1020 acgccgtggt
ggagaacgtg cccccgttgc gctggaagga attcgtgcgg cgcctagggc 1080
tgagcgacca cgagatcgat cggctggagc tgcagaacgg gcgctgcctg cgcgaggcgc
1140 aatacagcat gctggcgacc tggaggcggc gcacgccgcg gcgcgaggcc
acgctggagc 1200 tgctgggacg cgtgctccgc gacatggacc tgctgggctg
cctggaggac atcgaggagg 1260 cgctttgcgg ccccgccgcc ctcccgcccg
cgcccagtct tctcagatga tctagagtcg 1320 18 1380 DNA Homo sapien 18
ccatacccgt ttttttgggc tagcaggagg aattcaccct gcaggtcgac atgggactgg
60 tccctcacct aggggacagg gagaagagag atagtgtgtg tccccaagga
aaatatatcc 120 accctcaaaa taattcgatt tgctgtacca agtgccacaa
aggaacctac ttgtacaatg 180 actgtccagg cccggggcag gatacggact
gcagggagtg tgagagcggc tccttcaccg 240 cttcagaaaa ccacctcaga
cactgcctca gctgctccaa atgccgaaag gaaatgggtc 300 aggtggagat
ctcttcttgc acagtggacc gggacaccgt gtgtggctgc aggaagaacc 360
agtaccggca ttattggagt gaaaaccttt tccagtgctt caattgcagc ctctgcctca
420 atgggaccgt gcacctctcc tgccaggaga aacagaacac cgtgtgcacc
tgccatgcag 480 gtttctttct aagagaaaac gagtgtgtct cctgtagtaa
ctgtaagaaa agcctggagt 540 gcacgaagtt gtgcctaccc cagattgaga
atgttaaggg cactgaggac tcaggcacca 600 cagtgctgtt gcccctggtc
attttctttg gtctttgcct tttatccctc ctcttcattg 660 gtttaatgta
tcgctaccaa cggtggaagt ccaagctcta ctccattgtt tgtgggaaat 720
cgacacctga aaaagagggg gagcttgaag gaactactac taagcccctg gccccaaacc
780 caagcttcag tcccactcca ggcttcaccc ccaccctggg cttcagtccc
gtgcccagtt 840 ccaccttcac ctccagctcc acctataccc ccggtgactg
tcccaacttt gcggctcccc 900 gcagagaggt ggcaccaccc tatcaggggg
ctgaccccat ccttgcgaca gccctcgcct 960 ccgaccccat ccccaacccc
cttcagaagt gggaggacag cgcccacaag ccacagagcc 1020 tagacactga
tgaccccgcg acgctgtacg ccgtggtgga gaacgtgccc ccgttgcgct 1080
ggaaggaatt cgtgcggcgc ctagggctga gcgaccacga gatcgatcgg ctggagctgc
1140 agaacgggcg ctgcctgcgc gaggcgcaat acagcatgct ggcgacctgg
aggcggcgca 1200 cgccgcggcg cgaggccacg ctggagctgc tgggacgcgt
gctccgcgac atggacctgc 1260 tgggctgcct ggaggacatc gaggaggcgc
tttgcggccc cgccgccctc ccgcccgcgc 1320 ccagtcttct cagataataa
ggtaccgagc tcgaattcgt aatcatggtc atagctgttt 1380 19 780 DNA Homo
sapien 19 gtttttttgg gctagcagga ggaattcatg agcactgaaa gcatgatccg
ggacgtggag 60 ctggccgagg aggcgctccc caagaagaca ggggggcccc
agggctccag gcggtgcttg 120 ttcctcagcc tcttctcctt cctgatcgtg
gcaggcgcca ccacgctctt ctgcctgctg 180 cactttggag tgatcggccc
ccagagggaa gagttcccca gggacctctc tctaatcagc 240 cctctggccc
aggcagtcag atcatcttct cgaaccccga gtgacaagcc tgtagcccat 300
gttgtagcaa accctcaagc tgaggggcag ctccagtggc tgaaccgccg ggccaatgcc
360 ctcctggcca atggcgtgga gctgagagat aaccagctgg tggtgccatc
agagggcctg 420 tacctcatct actcccaggt cctcttcaag ggccaaggct
gcccctccac ccatgtgctc 480 ctcacccaca ccatcagccg catcgccgtc
tcctaccaga ccaaggtcaa cctcctctct 540 gccatcaaga gcccctgcca
gagggagacc ccagaggggg ctgaggccaa gccctggtat 600 gagcccatct
atctgggagg ggtcttccag ctggagaagg gtgaccgact cagcgctgag 660
atcaatcggc ccgactatct cgactttgcc gagtctgggc aggtctactt tgggatcatt
720 gccctgtgat aagcttggcc cgcgggcccg ggatccaccg gatctagata
actgatcata 780 20 300 DNA Artificial Sequence Gene encoding a
fusion protein 20 gtttttttgg gctagcagga ggaattcacc atggtaccat
gaacttgggg aatcgactgt 60 ttattctgat agcggtctta cttcccctcg
cagtattact gctcaatagt gactctgaat 120 gtcccctgtc ccacgatggg
tactgcctcc atgatggtgt gtgcatgtat attgaagcat 180 tggacaagta
tgcatgcaac tgtgttgttg gctacatcgg ggagcgatgt cagtaccgag 240
acctgaagtg gtgggaactg cgctaataag cttggcccgc gggcccggga tccaccggat
300 21 1620 DNA Artificial Sequence Gene encoding a fusion
protein 21 gtttttttgg gctagcagga ggaattcacc atgaacttgg ggaatcgact
gtttattctg 60 atagcggtct tacttcccct cgcagtatta ctgctctcat
tcacattgag cgtcaccgtt 120 cagcagcctc agttgacatt aacggcggcc
gtcattggtg atggcgcacc ggctaatggg 180 aaaactgcaa tcaccgttga
gttcaccgtt gctgattttg aggggaaacc cttagccggg 240 caggaggtgg
tgataaccac caataatggt gcgctaccga ataaaatcac ggaaaagaca 300
gatgcaaatg gcgtcgcgcg cattgcatta accaatacga cagatggcgt gacggtagtc
360 acagcagaag tggaggggca acggcaaagt gttgataccc actttgttaa
gggtactatc 420 gcggcggata aatccactct ggctgcggta ccgacatcta
tcatcgctga tggtctaatg 480 gcttcaacca tcacgttgga gttgaaggat
acctatgggg acccgcaggc tggcgcgaat 540 gtggcttttg acacaacctt
aggcaatatg ggcgttatca cggatcacaa tgacggcact 600 tatagcgcac
cattgaccag taccacgttg ggggtagcaa cagtaacggt gaaagtggat 660
ggggctgcgt tcagtgtgcc gagtgtgacg gttaatttca cggcagatcc tattccagat
720 gctggccgct ccagtttcac cgtctccaca ccggatatct tggctgatgg
cacgatgagt 780 tccacattat cctttgtccc tgtcgataag aatggccatt
ttatcagtgg gatgcagggc 840 ttgagtttta ctcaaaacgg tgtgccggtg
agtattagcc ccattaccga gcagccagat 900 agctataccg cgacggtggt
tgggaatagt gtcggtgatg tcacaatcac gccgcaggtt 960 gataccctga
tactgagtac attgcagaaa aaaatatccc tattcccggt acctacgctg 1020
accggtattc tggttaacgg gcaaaatttc gctacggata aagggttccc gaaaacgatc
1080 tttaaaaacg ccacattcca gttacagatg gataacgatg ttgctaataa
tactcagtat 1140 gagtggtcgt cgtcattcac acccaatgta tcggttaacg
atcagggtca ggtgacgatt 1200 acctaccaaa cctatagcga agtggctgtg
acggcgaaaa gtaaaaaatt cccaagttat 1260 tcggtgagtt atcggttcta
cccaaatcgg tggatatacg atggcggcag atcgctggta 1320 tccagtctcg
aggccagcag acaatgccaa ggttcagata tgtctgcggt tcttgaatcc 1380
tcacgtgcaa ccaacggaac gcgtgcgcct gacgggacat tgtggggcga gtgggggagc
1440 ttgaccgcgt atagttctga ttggcaatct ggtgaatatt gggtcaaaaa
gaccagcacg 1500 gattttgaaa ccatgaatat ggacacaggc gcactgcaac
cagggcctgc atacttggcg 1560 ttcccgctct gtgcgctgtc aatataactg
caggcatgca agcttggccc gcgggcccgg 1620 22 208 DNA E. coli 22
gaattcaggc gctttttaga ctggtcgtaa tgaaattcag caggatcaca ttctgcagat
60 gtcacggccg agacttatag tcgctttgtt tttatttttt aatgtatttg
tacatggaga 120 aaataaagtg aaacaaagca ctattgcact ggcactctta
ccgttactgt ttacccctgt 180 gacaaaagcc cggacaccag aatctaga 208 23
1546 DNA E. coli 23 gaattcaggc gctttttaga ctggtcgtaa tgaaattcag
caggatcaca ttctgcagat 60 gtcacggccg agacttatag tcgctttgtt
tttatttttt aatgtatttg tacatggaga 120 aaataaagtg aaacaaagca
ctattgcact ggcactctta ccgttactgt ttacccctgt 180 gacaaaagcc
cggacaccag aaatgcctgt tctggaaaac cgggctgctc agggcgatat 240
tactgcaccc ggcggtgctc gccgtttaac gggtgatcag actgccgctc tgcgtgattc
300 tcttagcgat aaacctgcaa aaaatattat tttgctgatt ggcgatggga
tgggggactc 360 ggaaattact gccgcacgta attatgccga aggtgcgggc
ggctttttta aaggtataga 420 tgccttaccg cttaccgggc aatacactca
ctatgcgctg aataaaaaaa ccggcaaacc 480 ggactacgtc accgactcgg
ctgcatcagc aaccgcctgg tcaaccggtg tcaaaaccta 540 taacggcgcg
ctgggcgtcg atattcacga aaaagatcac ccaacgattc tggaaatggc 600
aaaagccgca ggtctggcga ccggtaacgt ttctaccgca gagttgcagg atgccacgcc
660 cgctgcgctg gtggcacatg tgacctcgcg caaatgctac ggtccgagcg
cgaccagtga 720 aaaatgtccg ggtaacgctc tggaaaaagg cggaaaagga
tcgattaccg aacagctgct 780 taacgctcgt gccgacgtta cgcttggcgg
cggcgcaaaa acctttgctg aaacggcaac 840 cgctggtgaa tggcagggaa
aaacgctgcg tgaacaggca caggcgcgtg gttatcagtt 900 ggtgagcgat
gctgcctcac tgaattcggt gacggaagcg aatcagcaaa aacccctgct 960
tggcctgttt gctgacggca atatgccagt gcgctggcta ggaccgaaag caacgtacca
1020 tggcaatatc gataagcccg cagtcacctg tacgccaaat ccgcaacgta
atgacagtgt 1080 accaaccctg gcgcagatga ccgacaaagc cattgaattg
ttgagtaaaa atgagaaagg 1140 ctttttcctg caagttgaag gtgcgtcaat
cgataaacag gatcatgctg cgaatccttg 1200 tgggcaaatt ggcgagacgg
tcgatctcga tgaagccgta caacgggcgc tggaattcgc 1260 taaaaaggag
ggtaacacgc tggtcatagt caccgctgat cacgcccacg ccagccagat 1320
tgttgcgccg gataccaaag ctccgggcct cacccaggcg ctaaatacca aagatggcgc
1380 agtgatggtg atgagttacg ggaactccga agaggattca caagaacata
ccggcagtca 1440 gttgcgtatt gcggcgtatg gcccgcatgc cgccaatgtt
gttggactga ccgaccagac 1500 cgatctcttc tacaccatga aagccgctct
ggggctgaaa tctaga 1546 24 148 DNA E. coli 24 gaattcaggc gctttttaga
ctggtcgtaa tgaaattcag caggatcaca ttctgcagat 60 gaaaataaaa
acaggtgcac gcatcctcgc attatccgca ttaacgacga tgatgttttc 120
cgcctcggct ctcgccaaaa tctctaga 148 25 1174 DNA E. coli 25
gaattcaggc gctttttaga ctggtcgtaa tgaaattcag caggatcaca ttctgcagat
60 gaaaataaaa acaggtgcac gcatcctcgc attatccgca ttaacgacga
tgatgttttc 120 cgcctcggct ctcgccaaaa tcgaagaagg taaactggta
atctggatta acggcgataa 180 aggctataac ggtctcgctg aagtcggtaa
gaaattcgag aaagataccg gaattaaagt 240 caccgttgag catccggata
aactggaaga gaaattccca caggttgcgg caactggcga 300 tggccctgac
attatcttct gggcacacga ccgctttggt ggctacgctc aatctggcct 360
gttggctgaa atcaccccgg acaaagcgtt ccaggacaag ctgtatccgt ttacctggga
420 tgccgtacgt tacaacggca agctgattgc ttacccgatc gctgttgaag
cgttatcgct 480 gatttataac aaagatctgc tgccgaaccc gccaaaaacc
tgggaagaga tcccggcgct 540 ggataaagaa ctgaaagcga aaggtaagag
cgcgctgatg ttcaacctgc aagaaccgta 600 cttcacctgg ccgctgattg
ctgctgacgg gggttatgcg ttcaagtatg aaaacggcaa 660 gtacgacatt
aaagacgtgg gcgtggataa cgctggcgcg aaagcgggtc tgaccttcct 720
ggttgacctg attaaaaaca aacacatgaa tgcagacacc gattactcca tcgcagaagc
780 tgcctttaat aaaggcgaaa cagcgatgac catcaacggc ccgtgggcat
ggtccaacat 840 cgacaccagc aaagtgaatt atggtgtaac ggtactgccg
accttcaagg gtcaaccatc 900 caaaccgttc gttggcgtgc tgagcgcagg
tattaacgcc gccagtccga acaaagagct 960 ggcgaaagag ttcctcgaaa
actatctgct gactgatgaa ggtctggaag cggttaataa 1020 agacaaaccg
ctgggtgccg tagcgctgaa gtcttacgag gaagagttgg cgaaagatcc 1080
acgtattgcc gccaccatgg aaaacgccca gaaaggtgaa atcatgccga acatcccgca
1140 gatgtccgct ttctggtatg ccgtgcgttc taga 1174 26 3840 DNA
Artificial Sequence Gene encoding a fusion protein 26 accatatgcg
gtgtgaaata ccgcacagat gcgtaaggag aaaataccgc atcaggcgcc 60
atacgcgaca gcgcgcaata accgttctcg actcataaaa gtgatgccgc tataatgccg
120 cgtcctattt gaatgctttc gggatgattc tggtaacagg gaatgtgatt
gattataaga 180 acatcccggt tccgcgaagc caacaacctg tgcttgcggg
gtaagagttg accgagcact 240 gtgatttttt gaggtaacaa gatgcaagtt
tcagttgaaa ccactcaagg ccttggccgc 300 cgtgtaacga ttactatcgc
tgctgacagc atcgagaccg ctgttaaaag cgagctggtc 360 aacgttgcga
aaaaagtacg tattgacggc ttccgcaaag gcaaagtgcc aatgaatatc 420
gttgctcagc gttatggcgc gtctgtacgc caggacgttc tgggtgacct gatgagccgt
480 aacttcattg acgccatcat taaagaaaaa atcaatccgg ctggcgcacc
gacttatgtt 540 ccgggcgaat acaagctggg tgaagacttc acttactctg
tagagtttga agtttatccg 600 gaagttgaac tgcagggtct ggaagcgatc
gaagttgaaa aaccgatcgt tgaagtgacc 660 gacgctgacg ttgacggcat
gctggatact ctgcgtaaac agcaggcgac ctggaaagaa 720 aaagacggcg
ctgttgaagc agaagaccgc gtaaccatcg acttcaccgg ttctgtagac 780
ggcgaagagt tcgaaggcgg taaagcgtct gatttcgtac tggcgatggg ccagggtcgt
840 atgatcccgg gctttgaaga cggtatcaaa ggccacaaag ctggcgaaga
gttcaccatc 900 gacgtgacct tcccggaaga ataccacgca gaaaacctga
aaggtaaagc agcgaaattc 960 gctatcaacc tgaagaaagt tgaagagcgt
gaactgccgg aactgactgc agaattcatc 1020 aaacgtttcg gcgttgaaga
tggttccgta gaaggtctgc gcgctgaagt gcgtaaaaac 1080 atggagcgcg
agctgaagag cgccatccgt aaccgcgtta agtctcaggc gatcgaaggt 1140
ctggtaaaag ctaacgacat cgacgtaccg gctgcgctga tcgacagcga aatcgacgtt
1200 ctgcgtcgcc aggctgcaca gcgtttcggt ggcaacgaaa aacaagctct
ggaactgccg 1260 cgcgaactgt tcgaagaaca ggctaaacgc cgcgtagttg
ttggcctgct gctgggcgaa 1320 gttatccgca ccaacgagct gaaagctgac
gaagagcgcg tgaaaggcct gatcgaagag 1380 atggcttctg cgtacgaaga
tccgaaagaa gttatcgagt tctacagcaa aaacaaagaa 1440 ctgatggaca
acatgcgcaa tgttgctctg gaagaacagg ctgttgaagc tgtactggcg 1500
aaagcgaaag tgactgaaaa agaaaccact ttcaacgagc tgatgaacca gcaggcgtaa
1560 taataatcta gaggtagcac aatcagattc gcttatgacg gcgatgaaga
aattgcgatg 1620 aaatgtgagg tgaatcaggg ttttcacccg attttgtgct
gatcagaatt ttttttcttt 1680 ttcccccttg aaggggcgaa gcctcatccc
catttctctg gtcaccagcc gggaaaccac 1740 gtaagctccg gcgtcaccca
taacagatac ggactttctc aaaggagagt tatcaatgaa 1800 tattcgtcca
ttgcatgatc gcgtgatcgt caagcgtaaa gaagttgaaa ctaaatctgc 1860
tggcggcatc gttctgaccg gctctgcagc ggctaaatcc acccgcggcg aagtgctggc
1920 tgtcggcaat ggccgtatcc ttgaaaatgg cgaagtgaag ccgctggatg
tgaaagttgg 1980 cgacatcgtt attttcaacg atggctacgg tgtgaaatct
gagaagatcg acaatgaaga 2040 agtgttgatc atgtccgaaa gcgacattct
ggcaattgtt gaagcgtaat ccgcgcacga 2100 cactgaacat acgaatttaa
ggaataaaga taatggcagc taaagacgta aaattcggta 2160 acgacgctcg
tgtgaaaatg ctgcgcggcg taaacgtact ggcagatgca gtgaaagtta 2220
ccctcggtcc aaaaggccgt aacgtagttc tggataaatc tttcggtgca ccgaccatca
2280 ccaaagatgg tgtttccgtt gctcgtgaaa tcgaactgga agacaagttc
gaaaatatgg 2340 gtgcgcagat ggtgaaagaa gttgcctcta aagcaaacga
cgctgcaggc gacggtacca 2400 ccactgcaac cgtactggct caggctatca
tcactgaagg tctgaaagct gttgctgcgg 2460 gcatgaaccc gatggacctg
aaacgtggta tcgacaaagc ggttaccgct gcagttgaag 2520 aactgaaagc
gctgtccgta ccatgctctg actctaaagc gattgctcag gttggtacca 2580
tctccgctaa ctccgacgaa accgtaggta aactgatcgc tgaagcgatg gacaaagtcg
2640 gtaaagaagg cgttatcacc gttgaagacg gtaccggtct gcaggacgaa
ctggacgtgg 2700 ttgaaggtat gcagttcgac cgtggctacc tgtctcctta
cttcatcaac aagccggaaa 2760 ctggcgcagt agaactggaa agcccgttca
tcctgctggc tgacaagaaa atctccaaca 2820 tccgcgaaat gctgccggtt
ctggaagctg ttgccaaagc aggcaaaccg ctgctgatca 2880 tcgctgaaga
tgtagaaggc gaagcgctgg caactctggt tgttaacacc atgcgtggca 2940
tcgtgaaagt cgctgcggtt aaagcaccgg gcttcggcga tcgtcgtaaa gctatgctgc
3000 aggatatcgc aaccctgact ggcggtaccg tgatctctga agagatcggt
atggagctgg 3060 aaaaagcaac cctggaagac ctgggtcagg ctaaacgtgt
tgtgatcaac aaagacacca 3120 ccactatcat cgatggcgtg ggtgaagaag
ctgcaatcca gggccgtgtt gctcagatcc 3180 gtcagcagat tgaagaagca
acttctgact acgaccgtga aaaactgcag gaacgcgtag 3240 cgaaactggc
aggcggcgtt gcagttatca aagtgggtgc tgctaccgaa gttgaaatga 3300
aagagaaaaa agcacgcgtt gaagatgccc tgcacgcgac ccgtgctgcg gtagaagaag
3360 gcgtggttgc tggtggtggt gttgcgctga tccgcgtagc gtctaaactg
gctgacctgc 3420 gtggtcagaa cgaagaccag aacgtgggta tcaaagttgc
actgcgtgca atggaagctc 3480 cgctgcgtca gatcgtattg aactgcggcg
aagaaccgtc tgttgttgct aacaccgtta 3540 aaggcggcga cggcaactac
ggttacaacg cagcaaccga agaatacggc aacatgatcg 3600 acatgggtat
cctggatcca accaaagtaa ctcgttctgc tctgcagtac gcagcttctg 3660
tggctggcct gatgatcacc accgaatgca tggttaccga cctgccgaaa aacgatgcag
3720 ctgacttagg cgctgctggc ggtatgggcg gcatgggtgg catgggcggc
atgatgtaat 3780 aataagcttg catgcctgca ggtcgactct agaggatccc
cgggtaccga gctcgaattc 3840 27 480 DNA Artificial Sequence Gene
encoding a fusion protein 27 gaattcaggc gctttttaga ctggtcgtaa
tgaaattcag caggatcaca ttctgcagat 60 gatcgaagcc cgctctagac
tcgagagcga taaaattatt cacctgactg acgacagttt 120 tgacacggat
gtactcaaag cggacggggc gatcctcgtc gatttctggg cagagtggtg 180
cggtccgtgc aaaatgatcg ccccgattct ggatgaaatc gctgacgaat atcagggcaa
240 actgaccgtt gcaaaactga acatcgatca aaaccctggc actgcgccga
aatatggcat 300 ccgtggtatc ccgactctgc tgctgttcaa aaacggtgaa
gtggcggcaa ccaaagtggg 360 tgcactgtct aaaggtcagt tgaaagagtt
cctcgacgct aacctggcgc tcgaggatta 420 taaagatcat gatggcgatt
ataaagatca tgatgattaa taaggatccc cgggtaccga 480 28 1140 DNA Rat 28
atggcaacca cgcacgcgca ggggcacccg ccagtcttgg ggaatgatac tctccgggaa
60 cattatgatt acgtggggaa gctggcaggc aggctgcggg atccccctga
gggtagcacc 120 ctcatcacca ccatcctctt cttggtcacc tgtagcttca
tcgtcttgga gaacctgatg 180 gttttgattg ccatctggaa aaacaataaa
tttcataacc gcatgtactt tttcatcggc 240 aacttggctc tctgcgacct
gctggccggc atagcctaca aggtcaacat tctgatgtcc 300 ggtaggaaga
cgttcagcct gtctccaaca gtgtggttcc tcagggaggg cagtatgttc 360
gtagccctgg gcgcatccac atgcagctta ttggccattg ccattgagcg gcacctgacc
420 atgatcaaga tgaggccgta cgacgccaac aagaagcacc gcgtgttcct
tctgattggg 480 atgtgctggc taattgcctt ctcgctgggt gccctgccca
tcctgggctg gaactgcctg 540 gagaactttc ccgactgctc taccatcttg
cccctctact ccaagaaata cattgccttt 600 ctcatcagca tcttcacagc
cattctggtg accatcgtca tcttgtacgc gcgcatctac 660 ttcctggtca
agtccagcag ccgcagggtg gccaaccaca actccgagag atccatggcc 720
cttctgcgga ccgtagtgat cgtggtgagc gtgttcatcg cctgttggtc cccccttttc
780 atcctcttcc tcatcgatgt ggcctgcagg gcgaaggagt gctccatcct
cttcaagagt 840 cagtggttca tcatgctggc tgtcctcaac tcggccatga
accctgtcat ctacacgctg 900 gccagcaaag agatgcggcg tgctttcttc
cggttggtgt gcggctgtct ggtcaagggc 960 aaggggaccc aggcctcccc
gatgcagcct gctcttgacc cgagcagaag taaatcaagc 1020 tccagtaaca
acagcagcag ccactctcca aaggtcaagg aagacctgcc ccatgtggct 1080
acctcttcct gcgtcactga caaaacgagg tcgcttcaga atggggtcct ctgcaagtga
1140 29 379 PRT Rat 29 Met Ala Thr Thr His Ala Gln Gly His Pro Pro
Val Leu Gly Asn Asp 1 5 10 15 Thr Leu Arg Glu His Tyr Asp Tyr Val
Gly Lys Leu Ala Gly Arg Leu 20 25 30 Arg Asp Pro Pro Glu Gly Ser
Thr Leu Ile Thr Thr Ile Leu Phe Leu 35 40 45 Val Thr Cys Ser Phe
Ile Val Leu Glu Asn Leu Met Val Leu Ile Ala 50 55 60 Ile Trp Lys
Asn Asn Lys Phe His Asn Arg Met Tyr Phe Phe Ile Gly 65 70 75 80 Asn
Leu Ala Leu Cys Asp Leu Leu Ala Gly Ile Ala Tyr Lys Val Asn 85 90
95 Ile Leu Met Ser Gly Arg Lys Thr Phe Ser Leu Ser Pro Thr Val Trp
100 105 110 Phe Leu Arg Glu Gly Ser Met Phe Val Ala Leu Gly Ala Ser
Thr Cys 115 120 125 Ser Leu Leu Ala Ile Ala Ile Glu Arg His Leu Thr
Met Ile Lys Met 130 135 140 Arg Pro Tyr Asp Ala Asn Lys Lys His Arg
Val Phe Leu Leu Ile Gly 145 150 155 160 Met Cys Trp Leu Ile Ala Phe
Ser Leu Gly Ala Leu Pro Ile Leu Gly 165 170 175 Trp Asn Cys Leu Glu
Asn Phe Pro Asp Cys Ser Thr Ile Leu Pro Leu 180 185 190 Tyr Ser Lys
Lys Tyr Ile Ala Phe Leu Ile Ser Ile Phe Thr Ala Ile 195 200 205 Leu
Val Thr Ile Val Ile Leu Tyr Ala Arg Ile Tyr Phe Leu Val Lys 210 215
220 Ser Ser Ser Arg Arg Val Ala Asn His Asn Ser Glu Arg Ser Met Ala
225 230 235 240 Leu Leu Arg Thr Val Val Ile Val Val Ser Val Phe Ile
Ala Cys Trp 245 250 255 Ser Pro Leu Phe Ile Leu Phe Leu Ile Asp Val
Ala Cys Arg Ala Lys 260 265 270 Glu Cys Ser Ile Leu Phe Lys Ser Gln
Trp Phe Ile Met Leu Ala Val 275 280 285 Leu Asn Ser Ala Met Asn Pro
Val Ile Tyr Thr Leu Ala Ser Lys Glu 290 295 300 Met Arg Arg Ala Phe
Phe Arg Leu Val Cys Gly Cys Leu Val Lys Gly 305 310 315 320 Lys Gly
Thr Gln Ala Ser Pro Met Gln Pro Ala Leu Asp Pro Ser Arg 325 330 335
Ser Lys Ser Ser Ser Ser Asn Asn Ser Ser Ser His Ser Pro Lys Val 340
345 350 Lys Glu Asp Leu Pro His Val Ala Thr Ser Ser Cys Val Thr Asp
Lys 355 360 365 Thr Arg Ser Leu Gln Asn Gly Val Leu Cys Lys 370 375
30 32 DNA Artificial Sequence Cloning primer 30 aattgctagc
tccaccagca tcccagtggt ta 32 31 32 DNA Artificial Sequence Cloning
primer 31 aattggatcc ttaagaagaa gaattgacgt tt 32 32 32 DNA
Artificial Sequence Cloning primer 32 aattggatcc agaagaagaa
ttgacgtttc ca 32 33 52 DNA Artificial Sequence Cloning primer 33
aattggatcc ttaatgatga tgatgatgat gagaagaaga attgacgttt cc 52 34 24
DNA Artificial Sequence Cloning primer 34 ttatggcaac cacgcacgcg
cagg 24 35 21 DNA Artificial Sequence Cloning primer 35 agaccgtcac
ttgcagagga c 21 36 32 DNA Artificial Sequence Cloning primer 36
aattgctagc acgcacgcgc aggggcaccc gc 32 37 34 DNA Artificial
Sequence Cloning primer 37 aattggtacc tcacttgcag aggaccccat tctg 34
38 32 DNA Artificial Sequence Cloning primer 38 aattgctagc
acgcacgcgc aggggcaccc gc 32 39 21 DNA Artificial Sequence Cloning
primer 39 ggtcgccacc atggtgagca a 21 40 31 DNA Artificial Sequence
Cloning primer 40 ttaaggatcc ttacttgtac agctcgtcca t 31 41 21 DNA
Artificial Sequence Cloning primer 41 ggtcgccacc atggtgagca a 21 42
31 DNA Artificial Sequence Cloning primer 42 ttaaggatcc cttgtacagc
tcgtccatgc c 31 43 25 DNA Artificial Sequence Cloning primer 43
ccaatggaac ttaccaatga cgcgg 25 44 24 DNA Artificial Sequence
Cloning primer 44 gcttgcttac gcaggaatgc tggg 24 45 45 DNA
Artificial Sequence Cloning primer 45 cgcggctgca gatgtttgaa
ccaatggaac ttaccaatga cgcgg 45 46 45 DNA Artificial Sequence
Cloning primer 46 gcgcctctag attattaatc agcttgctta cgcaggaatg ctggg
45 47 31 DNA Artificial Sequence Cloning primer 47 gctagactgg
gcggttttat ggacagcaag c 31 48 35 DNA Artificial Sequence Cloning
primer 48 gcgttaataa ttcagaagaa ctcgtcaaga aggcg 35 49 99 DNA
Artificial Sequence Cloning primer 49 gcgcctactg acgtagttcg
accgtcggac tagcgaagtt cctatacttt ctagagaata 60 ggaacttcgc
tagactgggc ggttttatgg acagcaagc 99 50 109 DNA Artificial Sequence
Cloning primer 50 caagatgctt tgcctttgtc tgagttgata ctggctttgg
gaagttccta ttctctagaa 60 agtataggaa cttcgcgtta ataattcaga
agaactcgtc aagaaggcg
109 51 26 DNA Artificial Sequence Cloning primer 51 cgttaccaat
tatgacaact tgacgg 26 52 29 DNA Artificial Sequence Cloning primer
52 ttaatctttc tgcgaattga gatgacgcc 29 53 28 DNA Artificial Sequence
Cloning primer 53 gtgagtcgat attgtctttg ttgaccag 28 54 66 DNA
Artificial Sequence Cloning primer 54 gcctgcattg cggcgcttca
gtctccgctg catactgtcc cgttaccaat tatgacaact 60 tgacgg 66 55 69 DNA
Artificial Sequence Cloning primer 55 gcctgcattg cggcgcttca
gtctccgctg catactgtcc ttaatctttc tgcgaattga 60 gatgacgcc 69 56 76
DNA Artificial Sequence Cloning primer 56 gcctgcattg cggcgcttca
gtctccgctg catactgtcc ttaataaagt gagtcgatat 60 tgtctttgtt gaccag 76
57 66 DNA Artificial Sequence Cloning primer 57 gcctgcattg
cggcgcttca gtctccgctg catactgtcc cgttaccaat tatgacaact 60 tgacgg 66
58 30 DNA Artificial Sequence Cloning primer 58 gcctgttctg
gaaaaccggg ctgctcaggg 30 59 28 DNA Artificial Sequence Cloning
primer 59 gcggctttca tggtgtagaa gagatcgg 28 60 43 DNA Artificial
Sequence Cloning primer 60 ccgcgctgca gatgcctgtt ctggaaaacc
gggctgctca ggg 43 61 58 DNA Artificial Sequence Cloning primer 61
gcgcctctag attattattt cagccccaga gcggctttca tggtgtagaa gagatcgg 58
62 24 DNA Artificial Sequence Cloning primer 62 gtcacggccg
agacttatag tcgc 24 63 28 DNA Artificial Sequence Cloning primer 63
gcggctttca tggtgtagaa gagatcgg 28 64 37 DNA Artificial Sequence
Cloning primer 64 ccgcgctgca gatgtcacgg ccgagactta tagtcgc 37 65 58
DNA Artificial Sequence Cloning primer 65 gcgcctctag attattattt
cagccccaga gcggctttca tggtgtagaa gagatcgg 58 66 109 DNA Artificial
Sequence Cloning primer 66 ccgcgctgca gatgaacttg gggaatcgac
tgtttattct gatagcggtc ttacttcccc 60 tcgcagtatt actgctcatg
cctgttctgg aaaaccgggc tgctcaggg 109 67 58 DNA Artificial Sequence
Cloning primer 67 gcgcctctag attattattt cagccccaga gcggctttca
tggtgtagaa gagatcgg 58 68 24 DNA Artificial Sequence Cloning primer
68 gcgaattgag atgacgccac tggc 24 69 25 DNA Artificial Sequence
Cloning primer 69 cctgctgaat ttcattaacg accag 25 70 48 DNA
Artificial Sequence Cloning primer 70 cggcgaagct taattaatct
ttctgcgaat tgagatgacg ccactggc 48 71 53 DNA Artificial Sequence
Cloning primer 71 cgccgtaatc gccgctgcag aatgtgatcc tgctgaattt
cattaacgac cag 53 72 22 DNA Artificial Sequence Cloning primer 72
cgcagcgctg ttcctttgct cg 22 73 23 DNA Artificial Sequence Cloning
primer 73 cctcattaag ataataatac tgg 23 74 33 DNA Artificial
Sequence Cloning primer 74 gccgcaagct tcgcagcgct gttcctttgc tcg 33
75 47 DNA Artificial Sequence Cloning primer 75 ccaatgcatt
ggttctgcag gactcctcat taagataata atactgg 47 76 19 DNA Artificial
Sequence Cloning primer 76 cgtctttagc cgggaaacg 19 77 18 DNA
Artificial Sequence Cloning primer 77 gcagatctcc tggcttgc 18 78 30
DNA Artificial Sequence Cloning primer 78 gccgcaagct tcgtctttag
ccgggaaacg 30 79 26 DNA Artificial Sequence Cloning primer 79
cggtcgacgc agatctcctg gcttgc 26 80 23 DNA Artificial Sequence
Cloning primer 80 caagccgtca attgtctgat tcg 23 81 22 DNA Artificial
Sequence Cloning primer 81 ggtgaattcc tcctgctagc cc 22 82 34 DNA
Artificial Sequence Cloning primer 82 gcgccaagct tcaagccgtc
aattgtctga ttcg 34 83 28 DNA Artificial Sequence Cloning primer 83
ctgcagggtg aattcctcct gctagccc 28 84 42 DNA Artificial Sequence
Cloning primer 84 gcttaactcg agcttaataa caagccgtca attgtctgat tc 42
85 34 DNA Artificial Sequence Cloning primer 85 gcttaaccgc
gggccaagct tgcatgcctg ctcc 34 86 26 DNA Artificial Sequence Cloning
primer 86 ggcaaccacg cacgcgcagg gccacc 26 87 25 DNA Artificial
Sequence Cloning primer 87 caatggtgat ggtgatgatg accgg 25 88 38 DNA
Artificial Sequence Cloning primer 88 cgcggtcgac atggcaacca
cgcacgcgca gggccacc 38 89 40 DNA Artificial Sequence Cloning primer
89 gcgccggtac cttatcaatg gtgatggtga tgatgaccgg 40 90 25 DNA
Artificial Sequence Cloning primer 90 ggggcaaccc gggaacggca gcgcc
25 91 30 DNA Artificial Sequence Cloning primer 91 gcagtgagtc
atttgtacta caattcctcc 30 92 37 DNA Artificial Sequence Cloning
primer 92 cgcggtcgac atggggcaac ccgggaacgg cagcgcc 37 93 49 DNA
Artificial Sequence Cloning primer 93 gcgccggatc cttattatag
cagtgagtca tttgtactac aattcctcc 49 94 28 DNA Artificial Sequence
Cloning primer 94 ggactggtcc ctcacctagg ggacaggg 28 95 27 DNA
Artificial Sequence Cloning primer 95 ctgagaagac tgggcgcggg cgggagg
27 96 42 DNA Artificial Sequence Cloning primer 96 cgcgggtcga
catgggactg gtccctcacc taggggacag gg 42 97 44 DNA Artificial
Sequence Cloning primer 97 gcgccggtac cttattactg agaagactgg
gcgcgggcgg gagg 44 98 16 DNA Artificial Sequence Cloning primer 98
gatagtgtgt gtcccc 16 99 17 DNA Artificial Sequence Cloning primer
99 ctgagaagac tgggcgc 17 100 27 DNA Artificial Sequence Cloning
primer 100 gggagaccat ggatagtgtg tgtcccc 27 101 32 DNA Artificial
Sequence Cloning primer 101 gcctcatcta gattactgag aagactgggc gc 32
102 26 DNA Artificial Sequence Cloning primer 102 gagcactgaa
agcatgatcc gggacg 26 103 28 DNA Artificial Sequence Cloning primer
103 cagggcaatg atcccaaagt agacctgc 28 104 39 DNA Artificial
Sequence Cloning primer 104 ccgcggaatt catgagcact gaaagcatga
tccgggacg 39 105 43 DNA Artificial Sequence Cloning primer 105
ggcgcaagct tatcacaggg caatgatccc aaagtagacc tgc 43 106 110 DNA
Artificial Sequence Cloning primer 106 tctgatagcg gtcttacttc
ccctcgcagt attactgctc aatagtgact ctgaatgtcc 60 cctgtcccac
gatgggtact gcctccatga tggtgtgtgc atgtatattg 110 107 101 DNA
Artificial Sequence Cloning primer 107 aggtctcggt actgacatcg
ctccccgatg tagccaacaa cacagttgca tgcatacttg 60 tccaatgctt
caatatacat gcacacacca tcatggaggc a 101 108 63 DNA Artificial
Sequence Cloning primer 108 ccgcgggtac catgaacttg gggaatcgac
tgtttattct gatagcggtc ttacttcccc 60 tcg 63 109 61 DNA Artificial
Sequence Cloning primer 109 gcgccaagct tattagcgca gttcccacca
cttcaggtct cggtactgac atcgctcccc 60 g 61 110 22 DNA Artificial
Sequence Cloning primer 110 tcattcacat tgagcgtcac cg 22 111 24 DNA
Artificial Sequence Cloning primer 111 ttatattgac agcgcacaga gcgg
24 112 101 DNA Artificial Sequence Cloning primer 112 gcaagaattc
accatgaact tggggaatcg actgtttatt ctgatagcgg tcttacttcc 60
cctcgcagta ttactgctct cattcacatt gagcgtcacc g 101 113 47 DNA
Artificial Sequence Cloning primer 113 cgcggttacg taagcaactg
cagttatatt gacagcgcac agagcgg 47 114 24 DNA Artificial Sequence
Cloning primer 114 gtcacggccg agacttatag tcgc 24 115 23 DNA
Artificial Sequence Cloning primer 115 ggtgtccggg cttttgtcac agg 23
116 37 DNA Artificial Sequence Cloning primer 116 cgcggctgca
gatgtcacgg ccgagactta tagtcgc 37 117 38 DNA Artificial Sequence
Cloning primer 117 cgcggtctag attctggtgt ccgggctttt gtcacagg 38 118
23 DNA Artificial Sequence Cloning primer 118 cagccccaga gcggctttca
tgg 23 119 37 DNA Artificial Sequence Cloning primer 119 cgcggtctag
atttcagccc cagagcggct ttcatgg 37 120 106 DNA Artificial Sequence
Cloning primer 120 cgcggctgca gatgaaaata aaaacaggtg cacgcatcct
cgcattatcc gcattaacga 60 cgatgatgtt ttccgcctcg gctctcgcca
aaatctctag acgcgg 106 121 106 DNA Artificial Sequence Cloning
primer 121 ccgcgtctag agattttggc gagagccgag gcggaaaaca tcatcgtcgt
taatgcggat 60 aatgcgagga tgcgtgcacc tgtttttatt ttcatctgca gccgcg
106 122 26 DNA Artificial Sequence Cloning primer 122 ggtgcacgca
tcctcgcatt atccgc 26 123 26 DNA Artificial Sequence Cloning primer
123 cggcatacca gaaagcggac atctgc 26 124 52 DNA Artificial Sequence
Cloning primer 124 cgcggctgca gatgaaaata aaaacaggtg cacgcatcct
cgcattatcc gc 52 125 42 DNA Artificial Sequence Cloning primer 125
cgcggtctag aacgcacggc ataccagaaa gcggacatct gc 42 126 27 DNA
Artificial Sequence Cloning primer 126 cgcgacagcg cgcaataacc
gttctcg 27 127 27 DNA Artificial Sequence Cloning primer 127
gctggttcat cagctcgttg aaagtgg 27 128 41 DNA Artificial Sequence
Cloning primer 128 gcgccggcgc catacgcgac agcgcgcaat aaccgttctc g 41
129 52 DNA Artificial Sequence Cloning primer 129 ggcgctctag
attattatta cgcctgctgg ttcatcagct cgttgaaagt gg 52 130 29 DNA
Artificial Sequence Cloning primer 130 ggtagcacaa tcagattcgc
ttatgacgg 29 131 25 DNA Artificial Sequence Cloning primer 131
gccgcccatg ccacccatgc cgccc 25 132 38 DNA Artificial Sequence
Cloning primer 132 gcgtctagag gtagcacaat cagattcgct tatgacgg 38 133
49 DNA Artificial Sequence Cloning primer 133 ggcgcaagct tattattaca
tcatgccgcc catgccaccc atgccgccc 49 134 27 DNA Artificial Sequence
Cloning primer 134 gcgataaaat tattcacctg actgacg 27 135 26 DNA
Artificial Sequence Cloning primer 135 gcgtcgagga actctttcaa ctgacc
26 136 66 DNA Artificial Sequence Cloning primer 136 cgcggctgca
gatgatcgaa gcccgctcta gactcgagag cgataaaatt attcacctga 60 ctgacg 66
137 101 DNA Artificial Sequence Cloning primer 137 ccgcgggatc
cttattaatc atcatgatct ttataatcgc catcatgatc tttataatcc 60
tcgagcgcca ggttagcgtc gaggaactct ttcaactgac c 101 138 65 DNA
Artificial Sequence Cloning primer 138 tatgtaagga ggttgtcgac
cggctcagtc tagaggtacc cgccctcatc cgaaagggcg 60 tattg 65 139 67 DNA
Artificial Sequence Cloning primer 139 gatccaatac gccctttcgg
atgagggcgg gtacctctag actgagccgg tcgacaacct 60 ccttaca 67 140 65
DNA Artificial Sequence Cloning primer 140 tatgtaagga ggttctgcag
cggctcagtc tagaggtacc cgccctcatc cgaaagggcg 60 tattg 65 141 67 DNA
Artificial Sequence Cloning primer 141 gatccaatac gccctttcgg
atgagggcgg gtacctctag actgagccgc tgcagaacct 60 ccttaca 67 142 66
DNA Artificial Sequence Cloning primer 142 gatcctaagg aggttgtcga
ccggctcagt ctagaggtac ccgccctcat ccgaaagggc 60 gtattc 66 143 66 DNA
Artificial Sequence Cloning primer 143 tcgagaatac gccctttcgg
atgagggcgg gtacctctag actgagccgg tcgacaacct 60 ccttag 66 144 66 DNA
Artificial Sequence Cloning primer 144 gatcctaagg aggttctgca
gcggctcagt ctagaggtac ccgccctcat ccgaaagggc 60 gtattc 66 145 66 DNA
Artificial Sequence Cloning primer 145 tcgagaatac gccctttcgg
atgagggcgg gtacctctag actgagccgc tgcagaacct 60 ccttag 66 146 4740
DNA Artificial Sequence Expression vector 146 tcgcgcgttt cggtgatgac
ggtgaaaacc tctgacacat gcagctcccg gagacggtca 60 cagcttgtct
gtaagcggat gccgggagca gacaagcccg tcagggcgcg tcagcgggtg 120
ttggcgggtg tcggggctgg cttaactatg cggcatcaga gcagattgta ctgagagtgc
180 accatatgcg gtgtgaaata ccgcacagat gcgtaaggag aaaataccgc
atcaggcgcc 240 attcgccatt caggctgcgc aactgttggg aagggcgatc
ggtgcgggcc tcttcgctat 300 tacgccagct ggcgaaaggg ggatgtgctg
caaggcgatt aagttgggta acgccagggt 360 tttcccagtc acgacgttgt
aaaacgacgg ccagtgccaa gcttaattaa tctttctgcg 420 aattgagatg
acgccactgg ctgggcgtca tcccggtttc ccgggtaaac accaccgaaa 480
aatagttact atcttcaaag ccacattcgg tcgaaatatc actgattaac aggcggctat
540 gctggagaag atattgcgca tgacacactc tgacctgtcg cagatattga
ttgatggtca 600 ttccagtctg ctggcgaaat tgctgacgca aaacgcgctc
actgcacgat gcctcatcac 660 aaaatttatc cagcgcaaag ggacttttca
ggctagccgc cagccgggta atcagcttat 720 ccagcaacgt ttcgctggat
gttggcggca acgaatcact ggtgtaacga tggcgattca 780 gcaacatcac
caactgcccg aacagcaact cagccatttc gttagcaaac ggcacatgct 840
gactactttc atgctcaagc tgaccgataa cctgccgcgc ctgcgccatc cccatgctac
900 ctaagcgcca gtgtggttgc cctgcgctgg cgttaaatcc cggaatcgcc
ccctgccagt 960 caagattcag cttcagacgc tccgggcaat aaataatatt
ctgcaaaacc agatcgttaa 1020 cggaagcgta ggagtgttta tcgtcagcat
gaatgtaaaa gagatcgcca cgggtaatgc 1080 gataagggcg atcgttgagt
acatgcaggc cattaccgcg ccagacaatc accagctcac 1140 aaaaatcatg
tgtatgttca gcaaagacat cttgcggata acggtcagcc acagcgactg 1200
cctgctggtc gctggcaaaa aaatcatctt tgagaagttt taactgatgc gccaccgtgg
1260 ctacctcggc cagagaacga agttgattat tcgcaatatg gcgtacaaat
acgttgagaa 1320 gattcgcgtt attgcagaaa gccatcccgt ccctggcgaa
tatcacgcgg tgaccagtta 1380 aactctcggc gaaaaagcgt cgaaaagtgg
ttactgtcgc tgaatccaca gcgataggcg 1440 atgtcagtaa cgctggcctc
gctgtggcgt agcagatgtc gggctttcat cagtcgcagg 1500 cggttcaggt
atcgctgagg cgtcagtccc gtttgctgct taagctgccg atgtagcgta 1560
cgcagtgaaa gagaaaattg atccgccacg gcatcccaat tcacctcatc ggcaaaatgg
1620 tcctccagcc aggccagaag caagttgaga cgtgatgcgc tgttttccag
gttctcctgc 1680 aaactgcttt tacgcagcaa gagcagtaat tgcataaaca
agatctcgcg actggcggtc 1740 gagggtaaat cattttcccc ttcctgctgt
tccatctgtg caaccagctg tcgcacctgc 1800 tgcaatacgc tgtggttaac
gcgccagtga gacggatact gcccatccag ctcttgtggc 1860 agcaactgat
tcagcccggc gagaaactga aatcgatccg gcgagcgata cagcacattg 1920
gtcagacaca gattatcggt atgttcatac agatgccgat catgatcgcg tacgaaacag
1980 accgtgccac cggtgatggt atagggctgc ccattaaaca catgaatacc
cgtgccatgt 2040 tcgacaatca caatttcatg aaaatcatga tgatgttcag
gaaaatccgc ctgcgggagc 2100 cggggttcta tcgccacgga cgcgttacca
gacggaaaaa aatccacact atgtaatacg 2160 gtcatactgg cctcctgatg
tcgtcaacac ggcgaaatag taatcacgag gtcaggttct 2220 taccttaaat
tttcgacgga aaaccacgta aaaaacgtcg atttttcaag atacagcgtg 2280
aattttcagg aaatgcggtg agcatcacat caccacaatt cagcaaattg tgaacatcat
2340 cacgttcatc tttccctggt tgccaatggc ccattttcct gtcagtaacg
agaaggtcgc 2400 gaattcaggc gctttttaga ctggtcgtaa tgaaattcag
gaggttgtcg actctagagg 2460 atccccgcgc cctcatccga aagggcgtat
tggtaccgag ctcgaattcg taatcatggt 2520 catagctgtt tcctgtgtga
aattgttatc cgctcacaat tccacacaac atacgagccg 2580 gaagcataaa
gtgtaaagcc tggggtgcct aatgagtgag ctaactcaca ttaattgcgt 2640
tgcgctcact gcccgctttc cagtcgggaa acctgtcgtg ccagctgcat taatgaatcg
2700 gccaacgcgc ggggagaggc ggtttgcgta ttgggcgctc ttccgcttcc
tcgctcactg 2760 actcgctgcg ctcggtcgtt cggctgcggc gagcggtatc
agctcactca aaggcggtaa 2820 tacggttatc cacagaatca ggggataacg
caggaaagaa catgtgagca aaaggccagc 2880 aaaaggccag gaaccgtaaa
aaggccgcgt tgctggcgtt tttccatagg ctccgccccc 2940 ctgacgagca
tcacaaaaat cgacgctcaa gtcagaggtg gcgaaacccg acaggactat 3000
aaagatacca ggcgtttccc cctggaagct ccctcgtgcg ctctcctgtt ccgaccctgc
3060 cgcttaccgg atacctgtcc gcctttctcc cttcgggaag cgtggcgctt
tctcatagct 3120 cacgctgtag gtatctcagt tcggtgtagg tcgttcgctc
caagctgggc tgtgtgcacg 3180 aaccccccgt tcagcccgac cgctgcgcct
tatccggtaa ctatcgtctt gagtccaacc 3240 cggtaagaca cgacttatcg
ccactggcag cagccactgg taacaggatt agcagagcga 3300 ggtatgtagg
cggtgctaca gagttcttga agtggtggcc taactacggc tacactagaa 3360
ggacagtatt tggtatctgc gctctgctga agccagttac cttcggaaaa agagttggta
3420 gctcttgatc cggcaaacaa accaccgctg gtagcggtgg tttttttgtt
tgcaagcagc 3480 agattacgcg cagaaaaaaa ggatctcaag aagatccttt
gatcttttct acggggtctg 3540 acgctcagtg gaacgaaaac tcacgttaag
ggattttggt catgagatta tcaaaaagga 3600 tcttcaccta gatcctttta
aattaaaaat gaagttttaa atcaatctaa agtatatatg 3660 agtaaacttg
gtctgacagt taccaatgct taatcagtga ggcacctatc tcagcgatct 3720
gtctatttcg ttcatccata gttgcctgac tccccgtcgt gtagataact acgatacggg
3780 agggcttacc atctggcccc agtgctgcaa tgataccgcg agacccacgc
tcaccggctc 3840 cagatttatc agcaataaac cagccagccg gaagggccga
gcgcagaagt ggtcctgcaa 3900 ctttatccgc ctccatccag tctattaatt
gttgccggga agctagagta agtagttcgc 3960 cagttaatag tttgcgcaac
gttgttgcca ttgctacagg catcgtggtg tcacgctcgt 4020 cgtttggtat
ggcttcattc agctccggtt cccaacgatc aaggcgagtt acatgatccc 4080
ccatgttgtg caaaaaagcg gttagctcct tcggtcctcc gatcgttgtc agaagtaagt
4140 tggccgcagt gttatcactc atggttatgg cagcactgca taattctctt
actgtcatgc 4200 catccgtaag atgcttttct gtgactggtg agtactcaac
caagtcattc tgagaatagt 4260 gtatgcggcg accgagttgc tcttgcccgg
cgtcaatacg ggataatacc gcgccacata 4320 gcagaacttt aaaagtgctc
atcattggaa aacgttcttc ggggcgaaaa ctctcaagga 4380 tcttaccgct
gttgagatcc agttcgatgt aacccactcg tgcacccaac tgatcttcag 4440
catcttttac tttcaccagc gtttctgggt gagcaaaaac aggaaggcaa aatgccgcaa
4500 aaaagggaat aagggcgaca cggaaatgtt gaatactcat actcttcctt
tttcaatatt 4560 attgaagcat ttatcagggt tattgtctca tgagcggata
catatttgaa tgtatttaga 4620 aaaataaaca aataggggtt ccgcgcacat
ttccccgaaa agtgccacct gacgtctaag 4680 aaaccattat tatcatgaca
ttaacctata aaaataggcg tatcacgagg ccctttcgtc 4740 147 4746 DNA
Artificial Sequence Expression vector 147 tcgcgcgttt cggtgatgac
ggtgaaaacc tctgacacat gcagctcccg gagacggtca 60 cagcttgtct
gtaagcggat gccgggagca gacaagcccg tcagggcgcg tcagcgggtg 120
ttggcgggtg tcggggctgg cttaactatg cggcatcaga gcagattgta ctgagagtgc
180 accatatgcg gtgtgaaata ccgcacagat gcgtaaggag aaaataccgc
atcaggcgcc 240 attcgccatt caggctgcgc aactgttggg aagggcgatc
ggtgcgggcc tcttcgctat 300 tacgccagct ggcgaaaggg ggatgtgctg
caaggcgatt aagttgggta acgccagggt 360 tttcccagtc acgacgttgt
aaaacgacgg ccagtgccaa gcttaattaa tctttctgcg 420 aattgagatg
acgccactgg ctgggcgtca tcccggtttc ccgggtaaac accaccgaaa 480
aatagttact atcttcaaag ccacattcgg tcgaaatatc actgattaac aggcggctat
540 gctggagaag atattgcgca tgacacactc tgacctgtcg cagatattga
ttgatggtca 600 ttccagtctg ctggcgaaat tgctgacgca aaacgcgctc
actgcacgat gcctcatcac 660 aaaatttatc cagcgcaaag ggacttttca
ggctagccgc cagccgggta atcagcttat 720 ccagcaacgt ttcgctggat
gttggcggca acgaatcact ggtgtaacga tggcgattca 780 gcaacatcac
caactgcccg aacagcaact cagccatttc gttagcaaac ggcacatgct 840
gactactttc atgctcaagc tgaccgataa cctgccgcgc ctgcgccatc cccatgctac
900 ctaagcgcca gtgtggttgc cctgcgctgg cgttaaatcc cggaatcgcc
ccctgccagt 960 caagattcag cttcagacgc tccgggcaat aaataatatt
ctgcaaaacc agatcgttaa 1020 cggaagcgta ggagtgttta tcgtcagcat
gaatgtaaaa gagatcgcca cgggtaatgc 1080 gataagggcg atcgttgagt
acatgcaggc cattaccgcg ccagacaatc accagctcac 1140 aaaaatcatg
tgtatgttca gcaaagacat cttgcggata acggtcagcc acagcgactg 1200
cctgctggtc gctggcaaaa aaatcatctt tgagaagttt taactgatgc gccaccgtgg
1260 ctacctcggc cagagaacga agttgattat tcgcaatatg gcgtacaaat
acgttgagaa 1320 gattcgcgtt attgcagaaa gccatcccgt ccctggcgaa
tatcacgcgg tgaccagtta 1380 aactctcggc gaaaaagcgt cgaaaagtgg
ttactgtcgc tgaatccaca gcgataggcg 1440 atgtcagtaa cgctggcctc
gctgtggcgt agcagatgtc gggctttcat cagtcgcagg 1500 cggttcaggt
atcgctgagg cgtcagtccc gtttgctgct taagctgccg atgtagcgta 1560
cgcagtgaaa gagaaaattg atccgccacg gcatcccaat tcacctcatc ggcaaaatgg
1620 tcctccagcc aggccagaag caagttgaga cgtgatgcgc tgttttccag
gttctcctgc 1680 aaactgcttt tacgcagcaa gagcagtaat tgcataaaca
agatctcgcg actggcggtc 1740 gagggtaaat cattttcccc ttcctgctgt
tccatctgtg caaccagctg tcgcacctgc 1800 tgcaatacgc tgtggttaac
gcgccagtga gacggatact gcccatccag ctcttgtggc 1860 agcaactgat
tcagcccggc gagaaactga aatcgatccg gcgagcgata cagcacattg 1920
gtcagacaca gattatcggt atgttcatac agatgccgat catgatcgcg tacgaaacag
1980 accgtgccac cggtgatggt atagggctgc ccattaaaca catgaatacc
cgtgccatgt 2040 tcgacaatca caatttcatg aaaatcatga tgatgttcag
gaaaatccgc ctgcgggagc 2100 cggggttcta tcgccacgga cgcgttacca
gacggaaaaa aatccacact atgtaatacg 2160 gtcatactgg cctcctgatg
tcgtcaacac ggcgaaatag taatcacgag gtcaggttct 2220 taccttaaat
tttcgacgga aaaccacgta aaaaacgtcg atttttcaag atacagcgtg 2280
aattttcagg aaatgcggtg agcatcacat caccacaatt cagcaaattg tgaacatcat
2340 cacgttcatc tttccctggt tgccaatggc ccattttcct gtcagtaacg
agaaggtcgc 2400 gaattcaggc gctttttaga ctggtcgtaa tgaaattcag
gaggttctgc aggtcgactc 2460 tagaggatcc ccgcgccctc atccgaaagg
gcgtattggt accgagctcg aattcgtaat 2520 catggtcata gctgtttcct
gtgtgaaatt gttatccgct cacaattcca cacaacatac 2580 gagccggaag
cataaagtgt aaagcctggg gtgcctaatg agtgagctaa ctcacattaa 2640
ttgcgttgcg ctcactgccc gctttccagt cgggaaacct gtcgtgccag ctgcattaat
2700 gaatcggcca acgcgcgggg agaggcggtt tgcgtattgg gcgctcttcc
gcttcctcgc 2760 tcactgactc gctgcgctcg gtcgttcggc tgcggcgagc
ggtatcagct cactcaaagg 2820 cggtaatacg gttatccaca gaatcagggg
ataacgcagg aaagaacatg tgagcaaaag 2880 gccagcaaaa ggccaggaac
cgtaaaaagg ccgcgttgct ggcgtttttc cataggctcc 2940 gcccccctga
cgagcatcac aaaaatcgac gctcaagtca gaggtggcga aacccgacag 3000
gactataaag ataccaggcg tttccccctg gaagctccct cgtgcgctct cctgttccga
3060 ccctgccgct taccggatac ctgtccgcct ttctcccttc gggaagcgtg
gcgctttctc 3120 atagctcacg ctgtaggtat ctcagttcgg tgtaggtcgt
tcgctccaag ctgggctgtg 3180 tgcacgaacc ccccgttcag cccgaccgct
gcgccttatc cggtaactat cgtcttgagt 3240 ccaacccggt aagacacgac
ttatcgccac tggcagcagc cactggtaac aggattagca 3300 gagcgaggta
tgtaggcggt gctacagagt tcttgaagtg gtggcctaac tacggctaca 3360
ctagaaggac agtatttggt atctgcgctc tgctgaagcc agttaccttc ggaaaaagag
3420 ttggtagctc ttgatccggc aaacaaacca ccgctggtag cggtggtttt
tttgtttgca 3480 agcagcagat tacgcgcaga aaaaaaggat ctcaagaaga
tcctttgatc ttttctacgg 3540 ggtctgacgc tcagtggaac gaaaactcac
gttaagggat tttggtcatg agattatcaa 3600 aaaggatctt cacctagatc
cttttaaatt aaaaatgaag ttttaaatca atctaaagta 3660 tatatgagta
aacttggtct gacagttacc aatgcttaat cagtgaggca cctatctcag 3720
cgatctgtct atttcgttca tccatagttg cctgactccc cgtcgtgtag ataactacga
3780 tacgggaggg cttaccatct ggccccagtg ctgcaatgat accgcgagac
ccacgctcac 3840 cggctccaga tttatcagca ataaaccagc cagccggaag
ggccgagcgc agaagtggtc 3900 ctgcaacttt atccgcctcc atccagtcta
ttaattgttg ccgggaagct agagtaagta 3960 gttcgccagt taatagtttg
cgcaacgttg ttgccattgc tacaggcatc gtggtgtcac 4020 gctcgtcgtt
tggtatggct tcattcagct ccggttccca acgatcaagg cgagttacat 4080
gatcccccat gttgtgcaaa aaagcggtta gctccttcgg tcctccgatc gttgtcagaa
4140 gtaagttggc cgcagtgtta tcactcatgg ttatggcagc actgcataat
tctcttactg 4200 tcatgccatc cgtaagatgc ttttctgtga ctggtgagta
ctcaaccaag tcattctgag 4260 aatagtgtat gcggcgaccg agttgctctt
gcccggcgtc aatacgggat aataccgcgc 4320 cacatagcag aactttaaaa
gtgctcatca ttggaaaacg ttcttcgggg cgaaaactct 4380 caaggatctt
accgctgttg agatccagtt cgatgtaacc cactcgtgca cccaactgat 4440
cttcagcatc ttttactttc accagcgttt ctgggtgagc aaaaacagga aggcaaaatg
4500 ccgcaaaaaa gggaataagg gcgacacgga aatgttgaat actcatactc
ttcctttttc 4560 aatattattg aagcatttat cagggttatt gtctcatgag
cggatacata tttgaatgta 4620 tttagaaaaa taaacaaata ggggttccgc
gcacatttcc ccgaaaagtg ccacctgacg 4680 tctaagaaac cattattatc
atgacattaa cctataaaaa taggcgtatc acgaggccct 4740 ttcgtc 4746 148
3946 DNA Artificial Sequence Expression vector 148 tcgcgcgttt
cggtgatgac ggtgaaaacc tctgacacat gcagctcccg gagacggtca 60
cagcttgtct gtaagcggat gccgggagca gacaagcccg tcagggcgcg tcagcgggtg
120 ttggcgggtg tcggggctgg cttaactatg cggcatcaga gcagattgta
ctgagagtgc 180 accatatgcg gtgtgaaata ccgcacagat gcgtaaggag
aaaataccgc atcaggcgcc 240 attcgccatt caggctgcgc aactgttggg
aagggcgatc ggtgcgggcc tcttcgctat 300 tacgccagct ggcgaaaggg
ggatgtgctg caaggcgatt aagttgggta acgccagggt 360 tttcccagtc
acgacgttgt aaaacgacgg ccagtgccaa gcttcaagcc gtcaattgtc 420
tgattcgtta ccaattatga caacttgacg gctacatcat tcactttttc ttcacaaccg
480 gcacggaact cgctcgggct ggccccggtg cattttttaa atacccgcga
gaaatagagt 540 tgatcgtcaa aaccaacatt gcgaccgacg gtggcgatag
gcatccgggt ggtgctcaaa 600 agcagcttcg cctggctgat acgttggtcc
tcgcgccagc ttaagacgct aatccctaac 660 tgctggcgga aaagatgtga
cagacgcgac ggcgacaagc aaacatgctg tgcgacgctg 720 gcgatatcaa
aattgctgtc tgccaggtga tcgctgatgt actgacaagc ctcgcgtacc 780
cgattatcca tcggtggatg gagcgactcg ttaatcgctt ccatgcgccg cagtaacaat
840 tgctcaagca gatttatcgc cagcagctcc gaatagcgcc cttccccttg
cccggcgtta 900 atgatttgcc caaacaggtc gctgaaatgc ggctggtgcg
cttcatccgg gcgaaagaac 960 cccgtattgg caaatattga cggccagtta
agccattcat gccagtaggc gcgcggacga 1020 aagtaaaccc actggtgata
ccattcgcga gcctccggat gacgaccgta gtgatgaatc 1080 tctcctggcg
ggaacagcaa aatatcaccc ggtcggcaaa caaattctcg tccctgattt 1140
ttcaccaccc cctgaccgcg aatggtgaga ttgagaatat aacctttcat tcccagcggt
1200 cggtcgataa aaaaatcgag ataaccgttg gcctcaatcg gcgttaaacc
cgccaccaga 1260 tgggcattaa acgagtatcc cggcagcagg ggatcatttt
gcgcttcagc catacttttc 1320 atactcccgc cattcagaga agaaaccaat
tgtccatatt gcatcagaca ttgccgtcac 1380 tgcgtctttt actggctctt
ctcgctaacc aaaccggtaa ccccgcttat taaaagcatt 1440 ctgtaacaaa
gcgggaccaa agccatgaca aaaacgcgta acaaaagtgt ctataatcac 1500
ggcagaaaag tccacattga ttatttgcac ggcgtcacac tttgctatgc catagcattt
1560 ttatccataa gattagcgga tcctacctga cgctttttat cgcaactctc
tactgtttct 1620 ccatacccgt ttttttgggc tagcaggagg ccgtcgactc
tagaggatcc ccgcgccctc 1680 atccgaaagg gcgtattggt accgagctcg
aattcgtaat catggtcata gctgtttcct 1740 gtgtgaaatt gttatccgct
cacaattcca cacaacatac gagccggaag cataaagtgt 1800 aaagcctggg
gtgcctaatg agtgagctaa ctcacattaa ttgcgttgcg ctcactgccc 1860
gctttccagt cgggaaacct gtcgtgccag ctgcattaat gaatcggcca acgcgcgggg
1920 agaggcggtt tgcgtattgg gcgctcttcc gcttcctcgc tcactgactc
gctgcgctcg 1980 gtcgttcggc tgcggcgagc ggtatcagct cactcaaagg
cggtaatacg gttatccaca 2040 gaatcagggg ataacgcagg aaagaacatg
tgagcaaaag gccagcaaaa ggccaggaac 2100 cgtaaaaagg ccgcgttgct
ggcgtttttc cataggctcc gcccccctga cgagcatcac 2160 aaaaatcgac
gctcaagtca gaggtggcga aacccgacag gactataaag ataccaggcg 2220
tttccccctg gaagctccct cgtgcgctct cctgttccga ccctgccgct taccggatac
2280 ctgtccgcct ttctcccttc gggaagcgtg gcgctttctc atagctcacg
ctgtaggtat 2340 ctcagttcgg tgtaggtcgt tcgctccaag ctgggctgtg
tgcacgaacc ccccgttcag 2400 cccgaccgct gcgccttatc cggtaactat
cgtcttgagt ccaacccggt aagacacgac 2460 ttatcgccac tggcagcagc
cactggtaac aggattagca gagcgaggta tgtaggcggt 2520 gctacagagt
tcttgaagtg gtggcctaac tacggctaca ctagaaggac agtatttggt 2580
atctgcgctc tgctgaagcc agttaccttc ggaaaaagag ttggtagctc ttgatccggc
2640 aaacaaacca ccgctggtag cggtggtttt tttgtttgca agcagcagat
tacgcgcaga 2700 aaaaaaggat ctcaagaaga tcctttgatc ttttctacgg
ggtctgacgc tcagtggaac 2760 gaaaactcac gttaagggat tttggtcatg
agattatcaa aaaggatctt cacctagatc 2820 cttttaaatt aaaaatgaag
ttttaaatca atctaaagta tatatgagta aacttggtct 2880 gacagttacc
aatgcttaat cagtgaggca cctatctcag cgatctgtct atttcgttca 2940
tccatagttg cctgactccc cgtcgtgtag ataactacga tacgggaggg cttaccatct
3000 ggccccagtg ctgcaatgat accgcgagac ccacgctcac cggctccaga
tttatcagca 3060 ataaaccagc cagccggaag ggccgagcgc agaagtggtc
ctgcaacttt atccgcctcc 3120 atccagtcta ttaattgttg ccgggaagct
agagtaagta gttcgccagt taatagtttg 3180 cgcaacgttg ttgccattgc
tacaggcatc gtggtgtcac gctcgtcgtt tggtatggct 3240 tcattcagct
ccggttccca acgatcaagg cgagttacat gatcccccat gttgtgcaaa 3300
aaagcggtta gctccttcgg tcctccgatc gttgtcagaa gtaagttggc cgcagtgtta
3360 tcactcatgg ttatggcagc actgcataat tctcttactg tcatgccatc
cgtaagatgc 3420 ttttctgtga ctggtgagta ctcaaccaag tcattctgag
aatagtgtat gcggcgaccg 3480 agttgctctt gcccggcgtc aatacgggat
aataccgcgc cacatagcag aactttaaaa 3540 gtgctcatca ttggaaaacg
ttcttcgggg cgaaaactct caaggatctt accgctgttg 3600 agatccagtt
cgatgtaacc cactcgtgca cccaactgat cttcagcatc ttttactttc 3660
accagcgttt ctgggtgagc aaaaacagga aggcaaaatg ccgcaaaaaa gggaataagg
3720 gcgacacgga aatgttgaat actcatactc ttcctttttc aatattattg
aagcatttat 3780 cagggttatt gtctcatgag cggatacata tttgaatgta
tttagaaaaa taaacaaata 3840 ggggttccgc gcacatttcc ccgaaaagtg
ccacctgacg tctaagaaac cattattatc 3900 atgacattaa cctataaaaa
taggcgtatc acgaggccct ttcgtc 3946 149 3952 DNA Artificial Sequence
Expression vector 149 tcgcgcgttt cggtgatgac ggtgaaaacc tctgacacat
gcagctcccg gagacggtca 60 cagcttgtct gtaagcggat gccgggagca
gacaagcccg tcagggcgcg tcagcgggtg 120 ttggcgggtg tcggggctgg
cttaactatg cggcatcaga gcagattgta ctgagagtgc 180 accatatgcg
gtgtgaaata ccgcacagat gcgtaaggag aaaataccgc atcaggcgcc 240
attcgccatt caggctgcgc aactgttggg aagggcgatc ggtgcgggcc tcttcgctat
300 tacgccagct ggcgaaaggg ggatgtgctg caaggcgatt aagttgggta
acgccagggt 360 tttcccagtc acgacgttgt aaaacgacgg ccagtgccaa
gcttcaagcc gtcaattgtc 420 tgattcgtta ccaattatga caacttgacg
gctacatcat tcactttttc ttcacaaccg 480 gcacggaact cgctcgggct
ggccccggtg cattttttaa atacccgcga gaaatagagt 540 tgatcgtcaa
aaccaacatt gcgaccgacg gtggcgatag gcatccgggt ggtgctcaaa 600
agcagcttcg cctggctgat acgttggtcc tcgcgccagc ttaagacgct aatccctaac
660 tgctggcgga aaagatgtga cagacgcgac ggcgacaagc aaacatgctg
tgcgacgctg 720 gcgatatcaa aattgctgtc tgccaggtga tcgctgatgt
actgacaagc ctcgcgtacc 780 cgattatcca tcggtggatg gagcgactcg
ttaatcgctt ccatgcgccg cagtaacaat 840 tgctcaagca gatttatcgc
cagcagctcc gaatagcgcc cttccccttg cccggcgtta 900 atgatttgcc
caaacaggtc gctgaaatgc ggctggtgcg cttcatccgg gcgaaagaac 960
cccgtattgg caaatattga cggccagtta agccattcat gccagtaggc gcgcggacga
1020 aagtaaaccc actggtgata ccattcgcga gcctccggat gacgaccgta
gtgatgaatc 1080 tctcctggcg ggaacagcaa aatatcaccc ggtcggcaaa
caaattctcg tccctgattt 1140 ttcaccaccc cctgaccgcg aatggtgaga
ttgagaatat aacctttcat tcccagcggt 1200 cggtcgataa aaaaatcgag
ataaccgttg gcctcaatcg gcgttaaacc cgccaccaga 1260 tgggcattaa
acgagtatcc cggcagcagg ggatcatttt gcgcttcagc catacttttc 1320
atactcccgc cattcagaga agaaaccaat tgtccatatt gcatcagaca ttgccgtcac
1380 tgcgtctttt actggctctt ctcgctaacc aaaccggtaa ccccgcttat
taaaagcatt 1440 ctgtaacaaa gcgggaccaa agccatgaca aaaacgcgta
acaaaagtgt ctataatcac 1500 ggcagaaaag tccacattga ttatttgcac
ggcgtcacac tttgctatgc catagcattt 1560 ttatccataa gattagcgga
tcctacctga cgctttttat cgcaactctc tactgtttct 1620 ccatacccgt
ttttttgggc tagcaggagg ccctgcaggt cgactctaga ggatccccgc 1680
gccctcatcc gaaagggcgt attggtaccg agctcgaatt cgtaatcatg gtcatagctg
1740 tttcctgtgt gaaattgtta tccgctcaca attccacaca acatacgagc
cggaagcata 1800 aagtgtaaag cctggggtgc ctaatgagtg agctaactca
cattaattgc gttgcgctca 1860 ctgcccgctt tccagtcggg aaacctgtcg
tgccagctgc attaatgaat cggccaacgc 1920 gcggggagag gcggtttgcg
tattgggcgc tcttccgctt cctcgctcac tgactcgctg 1980 cgctcggtcg
ttcggctgcg gcgagcggta tcagctcact caaaggcggt aatacggtta 2040
tccacagaat caggggataa cgcaggaaag aacatgtgag caaaaggcca gcaaaaggcc
2100 aggaaccgta aaaaggccgc gttgctggcg tttttccata ggctccgccc
ccctgacgag 2160 catcacaaaa atcgacgctc aagtcagagg tggcgaaacc
cgacaggact ataaagatac 2220 caggcgtttc cccctggaag ctccctcgtg
cgctctcctg ttccgaccct gccgcttacc 2280 ggatacctgt ccgcctttct
cccttcggga agcgtggcgc tttctcatag ctcacgctgt 2340 aggtatctca
gttcggtgta ggtcgttcgc tccaagctgg gctgtgtgca cgaacccccc 2400
gttcagcccg accgctgcgc cttatccggt aactatcgtc ttgagtccaa cccggtaaga
2460 cacgacttat cgccactggc agcagccact ggtaacagga ttagcagagc
gaggtatgta 2520 ggcggtgcta cagagttctt gaagtggtgg cctaactacg
gctacactag aaggacagta 2580 tttggtatct gcgctctgct gaagccagtt
accttcggaa aaagagttgg tagctcttga 2640 tccggcaaac aaaccaccgc
tggtagcggt ggtttttttg tttgcaagca gcagattacg 2700 cgcagaaaaa
aaggatctca agaagatcct ttgatctttt ctacggggtc tgacgctcag 2760
tggaacgaaa actcacgtta agggattttg gtcatgagat tatcaaaaag gatcttcacc
2820 tagatccttt taaattaaaa atgaagtttt aaatcaatct aaagtatata
tgagtaaact 2880 tggtctgaca gttaccaatg cttaatcagt gaggcaccta
tctcagcgat ctgtctattt 2940 cgttcatcca tagttgcctg actccccgtc
gtgtagataa ctacgatacg ggagggctta 3000 ccatctggcc ccagtgctgc
aatgataccg cgagacccac gctcaccggc tccagattta 3060 tcagcaataa
accagccagc cggaagggcc gagcgcagaa gtggtcctgc aactttatcc 3120
gcctccatcc agtctattaa ttgttgccgg gaagctagag taagtagttc gccagttaat
3180 agtttgcgca acgttgttgc cattgctaca ggcatcgtgg tgtcacgctc
gtcgtttggt 3240 atggcttcat tcagctccgg ttcccaacga tcaaggcgag
ttacatgatc ccccatgttg 3300 tgcaaaaaag cggttagctc cttcggtcct
ccgatcgttg tcagaagtaa gttggccgca 3360 gtgttatcac tcatggttat
ggcagcactg cataattctc ttactgtcat gccatccgta 3420 agatgctttt
ctgtgactgg tgagtactca accaagtcat tctgagaata gtgtatgcgg 3480
cgaccgagtt gctcttgccc ggcgtcaata cgggataata ccgcgccaca tagcagaact
3540 ttaaaagtgc tcatcattgg aaaacgttct tcggggcgaa aactctcaag
gatcttaccg 3600 ctgttgagat ccagttcgat gtaacccact cgtgcaccca
actgatcttc agcatctttt 3660 actttcacca gcgtttctgg gtgagcaaaa
acaggaaggc aaaatgccgc aaaaaaggga 3720 ataagggcga cacggaaatg
ttgaatactc atactcttcc tttttcaata ttattgaagc 3780 atttatcagg
gttattgtct catgagcgga tacatatttg aatgtattta gaaaaataaa 3840
caaatagggg ttccgcgcac atttccccga aaagtgccac ctgacgtcta agaaaccatt
3900 attatcatga cattaaccta taaaaatagg cgtatcacga ggccctttcg tc 3952
150 3886 DNA Artificial Sequence Expression vector 150 tcgcgcgttt
cggtgatgac ggtgaaaacc tctgacacat gcagctcccg gagacggtca 60
cagcttgtct gtaagcggat gccgggagca gacaagcccg tcagggcgcg tcagcgggtg
120 ttggcgggtg tcggggctgg cttaactatg cggcatcaga gcagattgta
ctgagagtgc 180 accatatgcg gtgtgaaata ccgcacagat gcgtaaggag
aaaataccgc atcaggcgcc 240 attcgccatt caggctgcgc aactgttggg
aagggcgatc ggtgcgggcc tcttcgctat 300 tacgccagct ggcgaaaggg
ggatgtgctg caaggcgatt aagttgggta acgccagggt 360 tttcccagtc
acgacgttgt aaaacgacgg ccagtgccaa gcttttagcc gggaaacgtc 420
tggcggcgct gttggctaag tttgcggtat tgttgcggcg acatgccgac atatttgccg
480 aacgtgctgt aaaaacgact acttgaacga aagcctgccg tcagggcaat
atcgagaata 540 cttttatcgg tatcgctcag taacgcgcga acgtggttga
tgcgcatcgc ggtaatgtac 600 tgtttcatcg tcaattgcat gacccgctgg
aatatcccca ttgcatagtt ggcgttaagt 660 ttgacgtgct cagccacatc
gttgatggtc agcgcctgat catagttttc ggcaataaag 720 cccagcatct
ggctaacata aaattgcgca tggcgcgaga cgctgttttt gtgtgtgcgc 780
gaggttttat tgaccagaat cggttcccag ccagagaggc taaatcgctt gagcatcagg
840 ccaatttcat caatggcgag ctggcgaatt tgctcgttcg gactgtttaa
ttcctgctgc 900 cagcggcgca cttcaaacgg gctaagttgc tgtgtggcca
gtgatttgat caccatgccg 960 tgagtgacgt ggttaatcag gtctttatcc
agcggccagg agagaaacag atgcatcggc 1020 agattaaaaa tcgccatgct
ctgacaggtt ccggtatctg ttagttggtg cggtgtacag 1080 gcccagaaca
gcgtgatatg accctgattg atattcactt tttcattgtt gatcaggtat 1140
tccacatcgc catcgaaagg cacattcact tcgacctgac catgccagtg gctggtgggc
1200 atgatatgcg gtgcgcgaaa ctcaatctcc atccgctggt attccgaata
cagcgacagc 1260 gggctgcggg tctgtttttc gtcgctgctg cacataaacg
tatctgtatt catggatggc 1320 tctctttcct ggaatatcag aattatggca
ggagtgaggg aggatgactg
cgagtgggag 1380 cacggttttc accctcttcc cagaggggcg aggggactct
ccgagtatca tgaggccgaa 1440 aactctgctt ttcaggtaat ttattcccat
aaactcagat ttactgctgc ttcacgcagg 1500 atctgagttt atgggaatgc
tcaacctgga agccggaggt tttctgcaga ttcgcctgcc 1560 atgatgaagt
tattcaagca agccaggagg tcgtcgactc tagaggatcc ccgcgccctc 1620
atccgaaagg gcgtattggt accgagctcg aattcgtaat catggtcata gctgtttcct
1680 gtgtgaaatt gttatccgct cacaattcca cacaacatac gagccggaag
cataaagtgt 1740 aaagcctggg gtgcctaatg agtgagctaa ctcacattaa
ttgcgttgcg ctcactgccc 1800 gctttccagt cgggaaacct gtcgtgccag
ctgcattaat gaatcggcca acgcgcgggg 1860 agaggcggtt tgcgtattgg
gcgctcttcc gcttcctcgc tcactgactc gctgcgctcg 1920 gtcgttcggc
tgcggcgagc ggtatcagct cactcaaagg cggtaatacg gttatccaca 1980
gaatcagggg ataacgcagg aaagaacatg tgagcaaaag gccagcaaaa ggccaggaac
2040 cgtaaaaagg ccgcgttgct ggcgtttttc cataggctcc gcccccctga
cgagcatcac 2100 aaaaatcgac gctcaagtca gaggtggcga aacccgacag
gactataaag ataccaggcg 2160 tttccccctg gaagctccct cgtgcgctct
cctgttccga ccctgccgct taccggatac 2220 ctgtccgcct ttctcccttc
gggaagcgtg gcgctttctc atagctcacg ctgtaggtat 2280 ctcagttcgg
tgtaggtcgt tcgctccaag ctgggctgtg tgcacgaacc ccccgttcag 2340
cccgaccgct gcgccttatc cggtaactat cgtcttgagt ccaacccggt aagacacgac
2400 ttatcgccac tggcagcagc cactggtaac aggattagca gagcgaggta
tgtaggcggt 2460 gctacagagt tcttgaagtg gtggcctaac tacggctaca
ctagaaggac agtatttggt 2520 atctgcgctc tgctgaagcc agttaccttc
ggaaaaagag ttggtagctc ttgatccggc 2580 aaacaaacca ccgctggtag
cggtggtttt tttgtttgca agcagcagat tacgcgcaga 2640 aaaaaaggat
ctcaagaaga tcctttgatc ttttctacgg ggtctgacgc tcagtggaac 2700
gaaaactcac gttaagggat tttggtcatg agattatcaa aaaggatctt cacctagatc
2760 cttttaaatt aaaaatgaag ttttaaatca atctaaagta tatatgagta
aacttggtct 2820 gacagttacc aatgcttaat cagtgaggca cctatctcag
cgatctgtct atttcgttca 2880 tccatagttg cctgactccc cgtcgtgtag
ataactacga tacgggaggg cttaccatct 2940 ggccccagtg ctgcaatgat
accgcgagac ccacgctcac cggctccaga tttatcagca 3000 ataaaccagc
cagccggaag ggccgagcgc agaagtggtc ctgcaacttt atccgcctcc 3060
atccagtcta ttaattgttg ccgggaagct agagtaagta gttcgccagt taatagtttg
3120 cgcaacgttg ttgccattgc tacaggcatc gtggtgtcac gctcgtcgtt
tggtatggct 3180 tcattcagct ccggttccca acgatcaagg cgagttacat
gatcccccat gttgtgcaaa 3240 aaagcggtta gctccttcgg tcctccgatc
gttgtcagaa gtaagttggc cgcagtgtta 3300 tcactcatgg ttatggcagc
actgcataat tctcttactg tcatgccatc cgtaagatgc 3360 ttttctgtga
ctggtgagta ctcaaccaag tcattctgag aatagtgtat gcggcgaccg 3420
agttgctctt gcccggcgtc aatacgggat aataccgcgc cacatagcag aactttaaaa
3480 gtgctcatca ttggaaaacg ttcttcgggg cgaaaactct caaggatctt
accgctgttg 3540 agatccagtt cgatgtaacc cactcgtgca cccaactgat
cttcagcatc ttttactttc 3600 accagcgttt ctgggtgagc aaaaacagga
aggcaaaatg ccgcaaaaaa gggaataagg 3660 gcgacacgga aatgttgaat
actcatactc ttcctttttc aatattattg aagcatttat 3720 cagggttatt
gtctcatgag cggatacata tttgaatgta tttagaaaaa taaacaaata 3780
ggggttccgc gcacatttcc ccgaaaagtg ccacctgacg tctaagaaac cattattatc
3840 atgacattaa cctataaaaa taggcgtatc acgaggccct ttcgtc 3886 151 28
DNA Artificial Sequence Cloning primer 151 gcagaacctc ctgaatttca
ttacgacc 28 152 86 DNA Artificial Sequence Cloning primer 152
ccgcgggtac caatacgccc tttcggatga gggcgcgggg atcctctaga gtcgacgtcg
60 acaacctcct gaatttcatt acgacc 86 153 86 DNA Artificial Sequence
Cloning primer 153 ccgcgggtac caatacgccc tttcggatga gggcgcgggg
atcctctaga gtcgacctgc 60 agaacctcct gaatttcatt acgacc 86 154 38 DNA
Artificial Sequence Cloning primer 154 ctgcagggcc tcctgctagc
ccaaaaaaac gggtatgg 38 155 94 DNA Artificial Sequence Cloning
primer 155 ccgcgggtac caatacgccc tttcggatga gggcgcgggg atcctctaga
gtcgacgtcg 60 acggcctcct gctagcccaa aaaaacgggt atgg 94 156 94 DNA
Artificial Sequence Cloning primer 156 ccgcgggtac caatacgccc
tttcggatga gggcgcgggg atcctctaga gtcgacctgc 60 agggcctcct
gctagcccaa aaaaacgggt atgg 94 157 32 DNA Artificial Sequence
Cloning primer 157 cctcctggct tgcttgaata acttcatcat gg 32 158 91
DNA Artificial Sequence Cloning primer 158 ccgcgggtac caatacgccc
tttcggatga gggcgcgggg atcctctaga gtcgaccccc 60 tcctggcttg
cttgaataac ttcatcatgg c 91 159 2319 DNA Artificial Sequence Gene
encoding a fusion protein 159 gtcgacatga aaataaaaac aggtgcacgc
atcctcgcat tatccgcatt aacgacgatg 60 atgttttccg cctcggctct
cgccaaaatc gaagaaggta aactggtaat ctggattaac 120 ggcgataaag
gctataacgg tctcgctgaa gtcggtaaga aattcgagaa agataccgga 180
attaaagtca ccgttgagca tccggataaa ctggaagaga aattcccaca ggttgcggca
240 actggcgatg gccctgacat tatcttctgg gcacacgacc gctttggtgg
ctacgctcaa 300 tctggcctgt tggctgaaat caccccggac aaagcgttcc
aggacaagct gtatccgttt 360 acctgggatg ccgtacgtta caacggcaag
ctgattgctt acccgatcgc tgttgaagcg 420 ttatcgctga tttataacaa
agatctgctg ccgaacccgc caaaaacctg ggaagagatc 480 ccggcgctgg
ataaagaact gaaagcgaaa ggtaagagcg cgctgatgtt caacctgcaa 540
gaaccgtact tcacctggcc gctgattgct gctgacgggg gttatgcgtt caagtatgaa
600 aacggcaagt acgacattaa agacgtgggc gtggataacg ctggcgcgaa
agcgggtctg 660 accttcctgg ttgacctgat taaaaacaaa cacatgaatg
cagacaccga ttactccatc 720 gcagaagctg cctttaataa aggcgaaaca
gcgatgacca tcaacggccc gtgggcatgg 780 tccaacatcg acaccagcaa
agtgaattat ggtgtaacgg tactgccgac cttcaagggt 840 caaccatcca
aaccgttcgt tggcgtgctg agcgcaggta ttaacgccgc cagtccgaac 900
aaagagctgg cgaaagagtt cctcgaaaac tatctgctga ctgatgaagg tctggaagcg
960 gttaataaag acaaaccgct gggtgccgta gcgctgaagt cttacgagga
agagttggcg 1020 aaagatccac gtattgccgc caccatggaa aacgcccaga
aaggtgaaat catgccgaac 1080 atcccgcaga tgtccgcttt ctggtatgcc
gtgctgatcg aagcccgcac ctcggaatcc 1140 gacacggcag ggcccaacag
cgacctggac gtgaacactg acatttattc caaggtgctg 1200 gtgactgcta
tatacctggc actcttcgtg gtgggcactg tgggcaactc cgtgacagcc 1260
ttcactctag cgcggaagaa gtcactgcag agcctgcaga gcactgtgca ttaccacctg
1320 ggcagcctgg cactgtcgga cctgcttatc cttctgctgg ccatgcccgt
ggagctatac 1380 aacttcatct gggtacacca tccctgggcc tttggggacg
ctggctgccg tggctactat 1440 ttcctgcgtg atgcctgcac ctatgccaca
gccctcaatg tagccagcct gagtgtggag 1500 cgctacttgg ccatctgcca
tcccttcaag gccaagaccc tcatgtcccg cagccgcacc 1560 aagaaattca
tcagtgccat atggctagct tcggcgctgc tggctatacc catgcttttc 1620
accatgggcc tgcagaaccg cagtggtgac ggcacgcacc ctggcggcct ggtgtgcaca
1680 cccattgtgg acacagccac tgtcaaggtc gtcatccagg ttaacacctt
catgtccttc 1740 ctgtttccca tgttggtcat ctccatccta aacaccgtga
ttgccaacaa actgacagtc 1800 atggtgcacc aggccgccga gcagggccga
gtgtgcaccg tgggcacaca caacggttta 1860 gagcacagca cgttcaacat
gaccatcgag ccgggtcgtg tccaggccct gcgccacgga 1920 gtcctcgtct
tacgtgctgt ggtcattgcc tttgtggtct gctggctgcc ctaccacgtg 1980
cgacgcctga tgttctgcta tatctcggat gaacagtgga ctacgttcct cttcgatttc
2040 taccactatt tctacatgct aaccaacgct ctcttctacg tcagctccgc
catcaatccc 2100 atcctctaca acctggtctc cgccaacttc cgccaggtct
ttctgtccac gctggcctgc 2160 ctttgtcctg ggtggcgcca ccgccgaaag
aagaggccaa cgttctccag gaagcccaac 2220 agcatgtcca gcaaccatgc
cttttccacc agcgccaccc gggagaccct gtacgcggcc 2280 gcagattata
aagatgacga tgacaaataa taaggtacc 2319 160 1293 DNA Artificial
Sequence Gene encoding a fusion protein 160 gtcgacatga aaataaaaac
aggtgcacgc atcctcgcat tatccgcatt aacgacgatg 60 atgttttccg
cctcggctct cgccaaaatc atcgaagccc gcacctcgga atccgacacg 120
gcagggccca acagcgacct ggacgtgaac actgacattt attccaaggt gctggtgact
180 gctatatacc tggcactctt cgtggtgggc actgtgggca actccgtgac
agccttcact 240 ctagcgcgga agaagtcact gcagagcctg cagagcactg
tgcattacca cctgggcagc 300 ctggcactgt cggacctgct tatccttctg
ctggccatgc ccgtggagct atacaacttc 360 atctgggtac accatccctg
ggcctttggg gacgctggct gccgtggcta ctatttcctg 420 cgtgatgcct
gcacctatgc cacagccctc aatgtagcca gcctgagtgt ggagcgctac 480
ttggccatct gccatccctt caaggccaag accctcatgt cccgcagccg caccaagaaa
540 ttcatcagtg ccatatggct agcttcggcg ctgctggcta tacccatgct
tttcaccatg 600 ggcctgcaga accgcagtgg tgacggcacg caccctggcg
gcctggtgtg cacacccatt 660 gtggacacag ccactgtcaa ggtcgtcatc
caggttaaca ccttcatgtc cttcctgttt 720 cccatgttgg tcatctccat
cctaaacacc gtgattgcca acaaactgac agtcatggtg 780 caccaggccg
ccgagcaggg ccgagtgtgc accgtgggca cacacaacgg tttagagcac 840
agcacgttca acatgaccat cgagccgggt cgtgtccagg ccctgcgcca cggagtcctc
900 gtcttacgtg ctgtggtcat tgcctttgtg gtctgctggc tgccctacca
cgtgcgacgc 960 ctgatgttct gctatatctc ggatgaacag tggactacgt
tcctcttcga tttctaccac 1020 tatttctaca tgctaaccaa cgctctcttc
tacgtcagct ccgccatcaa tcccatcctc 1080 tacaacctgg tctccgccaa
cttccgccag gtctttctgt ccacgctggc ctgcctttgt 1140 cctgggtggc
gccaccgccg aaagaagagg ccaacgttct ccaggaagcc caacagcatg 1200
tccagcaacc atgccttttc caccagcgcc acccgggaga ccctgtacgc ggccgcagat
1260 tataaagatg acgatgacaa ataataaggt acc 1293 161 2652 DNA
Artificial Sequence Gene encoding a fusion protein 161 gtcgacatga
aaataaaaac aggtgcacgc atcctcgcat tatccgcatt aacgacgatg 60
atgttttccg cctcggctct cgccaaaatc gaagaaggta aactggtaat ctggattaac
120 ggcgataaag gctataacgg tctcgctgaa gtcggtaaga aattcgagaa
agataccgga 180 attaaagtca ccgttgagca tccggataaa ctggaagaga
aattcccaca ggttgcggca 240 actggcgatg gccctgacat tatcttctgg
gcacacgacc gctttggtgg ctacgctcaa 300 tctggcctgt tggctgaaat
caccccggac aaagcgttcc aggacaagct gtatccgttt 360 acctgggatg
ccgtacgtta caacggcaag ctgattgctt acccgatcgc tgttgaagcg 420
ttatcgctga tttataacaa agatctgctg ccgaacccgc caaaaacctg ggaagagatc
480 ccggcgctgg ataaagaact gaaagcgaaa ggtaagagcg cgctgatgtt
caacctgcaa 540 gaaccgtact tcacctggcc gctgattgct gctgacgggg
gttatgcgtt caagtatgaa 600 aacggcaagt acgacattaa agacgtgggc
gtggataacg ctggcgcgaa agcgggtctg 660 accttcctgg ttgacctgat
taaaaacaaa cacatgaatg cagacaccga ttactccatc 720 gcagaagctg
cctttaataa aggcgaaaca gcgatgacca tcaacggccc gtgggcatgg 780
tccaacatcg acaccagcaa agtgaattat ggtgtaacgg tactgccgac cttcaagggt
840 caaccatcca aaccgttcgt tggcgtgctg agcgcaggta ttaacgccgc
cagtccgaac 900 aaagagctgg cgaaagagtt cctcgaaaac tatctgctga
ctgatgaagg tctggaagcg 960 gttaataaag acaaaccgct gggtgccgta
gcgctgaagt cttacgagga agagttggcg 1020 aaagatccac gtattgccgc
caccatggaa aacgcccaga aaggtgaaat catgccgaac 1080 atcccgcaga
tgtccgcttt ctggtatgcc gtgctgatcg aagcccgcac ctcggaatcc 1140
gacacggcag ggcccaacag cgacctggac gtgaacactg acatttattc caaggtgctg
1200 gtgactgcta tatacctggc actcttcgtg gtgggcactg tgggcaactc
cgtgacagcc 1260 ttcactctag cgcggaagaa gtcactgcag agcctgcaga
gcactgtgca ttaccacctg 1320 ggcagcctgg cactgtcgga cctgcttatc
cttctgctgg ccatgcccgt ggagctatac 1380 aacttcatct gggtacacca
tccctgggcc tttggggacg ctggctgccg tggctactat 1440 ttcctgcgtg
atgcctgcac ctatgccaca gccctcaatg tagccagcct gagtgtggag 1500
cgctacttgg ccatctgcca tcccttcaag gccaagaccc tcatgtcccg cagccgcacc
1560 aagaaattca tcagtgccat atggctagct tcggcgctgc tggctatacc
catgcttttc 1620 accatgggcc tgcagaaccg cagtggtgac ggcacgcacc
ctggcggcct ggtgtgcaca 1680 cccattgtgg acacagccac tgtcaaggtc
gtcatccagg ttaacacctt catgtccttc 1740 ctgtttccca tgttggtcat
ctccatccta aacaccgtga ttgccaacaa actgacagtc 1800 atggtgcacc
aggccgccga gcagggccga gtgtgcaccg tgggcacaca caacggttta 1860
gagcacagca cgttcaacat gaccatcgag ccgggtcgtg tccaggccct gcgccacgga
1920 gtcctcgtct tacgtgctgt ggtcattgcc tttgtggtct gctggctgcc
ctaccacgtg 1980 cgacgcctga tgttctgcta tatctcggat gaacagtgga
ctacgttcct cttcgatttc 2040 taccactatt tctacatgct aaccaacgct
ctcttctacg tcagctccgc catcaatccc 2100 atcctctaca acctggtctc
cgccaacttc cgccaggtct ttctgtccac gctggcctgc 2160 ctttgtcctg
ggtggcgcca ccgccgaaag aagaggccaa cgttctccag gaagcccaac 2220
agcatgtcca gcaaccatgc cttttccacc agcgccaccc gggagaccct gtacgcggcc
2280 gcaagcgata aaattattca cctgactgac gacagttttg acacggatgt
actcaaagcg 2340 gacggggcga tcctcgtcga tttctgggca gagtggtgcg
gtccgtgcaa aatgatcgcc 2400 ccgattctgg atgaaatcgc tgacgaatat
cagggcaaac tgaccgttgc aaaactgaac 2460 atcgatcaaa accctggcac
tgcgccgaaa tatggcatcc gtggtatccc gactctgctg 2520 ctgttcaaaa
acggtgaagt ggcggcaacc aaagtgggtg cactgtctaa aggtcagttg 2580
aaagagttcc tcgacgctaa cctggcggcg gccgcagatt ataaagatga cgatgacaaa
2640 taataaggta cc 2652 162 1626 DNA Artificial Sequence Gene
encoding a fusion protein 162 gtcgacatga aaataaaaac aggtgcacgc
atcctcgcat tatccgcatt aacgacgatg 60 atgttttccg cctcggctct
cgccaaaatc atcgaagccc gcacctcgga atccgacacg 120 gcagggccca
acagcgacct ggacgtgaac actgacattt attccaaggt gctggtgact 180
gctatatacc tggcactctt cgtggtgggc actgtgggca actccgtgac agccttcact
240 ctagcgcgga agaagtcact gcagagcctg cagagcactg tgcattacca
cctgggcagc 300 ctggcactgt cggacctgct tatccttctg ctggccatgc
ccgtggagct atacaacttc 360 atctgggtac accatccctg ggcctttggg
gacgctggct gccgtggcta ctatttcctg 420 cgtgatgcct gcacctatgc
cacagccctc aatgtagcca gcctgagtgt ggagcgctac 480 ttggccatct
gccatccctt caaggccaag accctcatgt cccgcagccg caccaagaaa 540
ttcatcagtg ccatatggct agcttcggcg ctgctggcta tacccatgct tttcaccatg
600 ggcctgcaga accgcagtgg tgacggcacg caccctggcg gcctggtgtg
cacacccatt 660 gtggacacag ccactgtcaa ggtcgtcatc caggttaaca
ccttcatgtc cttcctgttt 720 cccatgttgg tcatctccat cctaaacacc
gtgattgcca acaaactgac agtcatggtg 780 caccaggccg ccgagcaggg
ccgagtgtgc accgtgggca cacacaacgg tttagagcac 840 agcacgttca
acatgaccat cgagccgggt cgtgtccagg ccctgcgcca cggagtcctc 900
gtcttacgtg ctgtggtcat tgcctttgtg gtctgctggc tgccctacca cgtgcgacgc
960 ctgatgttct gctatatctc ggatgaacag tggactacgt tcctcttcga
tttctaccac 1020 tatttctaca tgctaaccaa cgctctcttc tacgtcagct
ccgccatcaa tcccatcctc 1080 tacaacctgg tctccgccaa cttccgccag
gtctttctgt ccacgctggc ctgcctttgt 1140 cctgggtggc gccaccgccg
aaagaagagg ccaacgttct ccaggaagcc caacagcatg 1200 tccagcaacc
atgccttttc caccagcgcc acccgggaga ccctgtacgc ggccgcaagc 1260
gataaaatta ttcacctgac tgacgacagt tttgacacgg atgtactcaa agcggacggg
1320 gcgatcctcg tcgatttctg ggcagagtgg tgcggtccgt gcaaaatgat
cgccccgatt 1380 ctggatgaaa tcgctgacga atatcagggc aaactgaccg
ttgcaaaact gaacatcgat 1440 caaaaccctg gcactgcgcc gaaatatggc
atccgtggta tcccgactct gctgctgttc 1500 aaaaacggtg aagtggcggc
aaccaaagtg ggtgcactgt ctaaaggtca gttgaaagag 1560 ttcctcgacg
ctaacctggc agcggccgca gattataaag atgacgatga caaataataa 1620 ggtacc
1626 163 26 DNA Artificial Sequence Cloning primer 163 ggtgcacgca
tcctcgcatt atccgc 26 164 31 DNA Artificial Sequence Cloning primer
164 cgcacggcat accagaaagc ggacatctgc g 31 165 43 DNA Artificial
Sequence Cloning primer 165 ccgcggtcga catgaaaata aaaacaggtg
cacgcatcct cgc 43 166 66 DNA Artificial Sequence Cloning primer 166
gccgtgtcgg attccgaggt gcggccttcg atacgcacgg cataccaaga aagcgggatg
60 ttcggc 66 167 24 DNA Artificial Sequence Cloning primer 167
cctcggaatc cgacacggca gggc 24 168 26 DNA Artificial Sequence
Cloning primer 168 gtacagggtc tcccgggtgg cgctgg 26 169 43 DNA
Artificial Sequence Cloning primer 169 ccgcgatcga aggccgcacc
tcggaatccg acacggcagg gcc 43 170 73 DNA Artificial Sequence Cloning
primer 170 ggcgcggtac ctttgtcatc gtcatcttta taatctgcgg ccgcgtacag
ggtctcccgg 60 gtggcgctgg tgg 73 171 51 DNA Artificial Sequence
Cloning primer 171 gcggcggtac cttattattt gtcatcgtca tctttataat
ctgcggccgc g 51 172 79 DNA Artificial Sequence Cloning primer 172
ccgcattaac gacgatgatg ttttccgcct cggctctcgc caaaatcatc gaaggccgca
60 cctcggaatc cgacacggc 79 173 82 DNA Artificial Sequence Cloning
primer 173 ccgcggtcga catgaaaata aaaacaggtg cacgcatcct cgcattatcc
gcattaacga 60 cgatgatgtt ttccgcctcg gc 82 174 33 DNA Artificial
Sequence Cloning primer 174 ccgcgagcga taaaattatt cacctgactg acg 33
175 39 DNA Artificial Sequence Cloning primer 175 gcccgccagg
ttagcgtcga ggaactcttt caactgacc 39 176 37 DNA Artificial Sequence
Cloning primer 176 gcggccgcaa gcgataaaat tattcacctg actgacg 37 177
38 DNA Artificial Sequence Cloning primer 177 ggcgctgcgg ccgcatcatc
atgatcttta taatcgcc 38 178 2465 DNA Artificial Sequence Gene
encoding a fusion protein 178 gtcgacatgg ggcaacccgg gaacggcagc
gccttcttgc tggcacccaa tggaagccat 60 gcgccggacc acgacgtcac
gcagcaaagg gacgaggtgt gggtggtggg catgggcatc 120 gtcatgtctc
tcatcgtcct ggccatcgtg tttggcaatg tgctggtcat cacagccatt 180
gccaagttcg agcgtctgca gacggtcacc aactacttca tcacttcact ggcctgtgct
240 gatctggtca tgggcctagc agtggtgccc tttggggccg cccatattct
tatgaaaatg 300 tggacttttg gcaacttctg gtgcgagttt tggacttcca
ttgatgtgct gtgcgtcacg 360 gccagcattg agaccctgtg cgtgatcgca
gtggatcgct actttgccat tacttcacct 420 ttcaagtacc agagcctgct
gaccaagaat aaggcccggg tgatcattct gatggtgtgg 480 attgtgtcag
gccttayctc cttcttgccc attcagatgc actggtacag ggccacccac 540
caggaagcca tcaactgcta tgccaatgag acctgctgtg acttcttcac gaaccaagcc
600 tatgccattg cctcttccat cgtgtccttc tacgttcccc tggtgatcat
ggtcttcgtc 660 tactccaggg tctttcagga ggccaaaagg cagctccaga
agattgacaa atctgagggc 720 cgcttccatg tccagaacct tagccaggtg
gagcaggatg ggcggacggg gcatggactc 780 cgcagatctt ccaagttctg
cttgaaggag cacaaagccc tcaagacgtt aggcatcatc 840 atgggcactt
tcaccctctg ctggctgccc ttcttcatcg ttaacattgt gcatgtgatc 900
caggataacc tcatccgtaa ggaagtttac atcctcctaa attggatagg ctatgtcaat
960 tctggtttca atccccttat ctactgccgg agcccagatt tcaggattgc
cttccaggag 1020 cttctgtgcc tgcgcaggtc ttctttgaag gcctatggca
atggctactc cagcaacggc 1080 aacacagggg agcagagtgg atatcacgtg
gaacaggaga aagaaaataa actgctgtgt 1140 gaagacctcc caggcacgga
agactttgtg ggccatcaag gtactgtgcc tagcgataac 1200 attgattcac
aagggaggaa ttgtagtaca aatgactcac tgctagagcg tggccagacg 1260
gtcaccaacc
tgcagctcga gggctgcctc gggaacagta agaccgagga ccagcgcaac 1320
gaggagaagg cgcagcgtga ggccaacaaa aagatcgaga agcagctgca gaaggacaag
1380 caggtctacc gggccacgca ccgcctgctg ctgctgggtg ctggagaatc
tggtaaaagc 1440 accattgtga agcagatgag gatcctgcat gttaatgggt
ttaatggaga cagtgagaag 1500 gcaaccaaag tgcaggacat caaaaacaac
ctgaaagagg cgattgaaac cattgtggcc 1560 gccatgagca acctggtgcc
ccccgtggag ctggccaacc ccgagaacca gttcagagtg 1620 gactacatcc
tgagtgtgat gaacgtgcct gactttgact tccctcccga attctatgag 1680
catgccaagg ctctgtggga ggatgaagga gtgcgtgcct gctacgaacg ctccaacgag
1740 taccagctga ttgactgtgc ccagtacttc ctggacaaga tcgacgtgat
caagcaggct 1800 gactatgtgc cgagcgatca ggacctgctt cgctgccgtg
tcctgacttc tggaatcttt 1860 gagaccaagt tccaggtgga caaagtcaac
ttccacatgt ttgacgtggg tggccagcgc 1920 gatgaacgcc gcaagtggat
ccagtgcttc aacgatgtga ctgccatcat cttcgtggtg 1980 gccagcagca
gctacaacat ggtcatccgg gaggacaacc agaccaaccg cctgcaggag 2040
gctctgaacc tcttcaagag catctggaac aacagatggc tgcgcaccat ctctgtgatc
2100 ctgttcctca acaagcaaga tctgctcgct gagaaagtcc ttgctgggaa
atcgaagatt 2160 gaggactact ttccagaatt tgctcgctac actactcctg
aggatgctac tcccgagccc 2220 ggagaggacc cacgcgtgac ccgggccaag
tacttcattc gagatgagtt tctgaggatc 2280 agcactgcca gtggagatgg
gcgtcactac tgctaccctc atttcacctg cgctgtggac 2340 actgagaaca
tccgccgtgt gttcaacgac tgccgtgaca tcattcagcg catgcacctt 2400
cgtcagtacg agctgctcat cgattaataa tctagaggat ccccgcgccc tcatccgaaa
2460 gggcg 2465 179 2485 DNA Artificial Sequence Gene encoding a
fusion protein 179 gtcgacatgg ggcaacccgg gaacggcagc gccttcttgc
tggcacccaa tggaagccat 60 gcgccggacc acgacgtcac gcagcaaagg
gacgaggtgt gggtggtggg catgggcatc 120 gtcatgtctc tcatcgtcct
ggccatcgtg tttggcaatg tgctggtcat cacagccatt 180 gccaagttcg
agcgtctgca gacggtcacc aactacttca tcacttcact ggcctgtgct 240
gatctggtca tgggcctagc agtggtgccc tttggggccg cccatattct tatgaaaatg
300 tggacttttg gcaacttctg gtgcgagttt tggacttcca ttgatgtgct
gtgcgtcacg 360 gccagcattg agaccctgtg cgtgatcgca gtggatcgct
actttgccat tacttcacct 420 ttcaagtacc agagcctgct gaccaagaat
aaggcccggg tgatcattct gatggtgtgg 480 attgtgtcag gccttayctc
cttcttgccc attcagatgc actggtacag ggccacccac 540 caggaagcca
tcaactgcta tgccaatgag acctgctgtg acttcttcac gaaccaagcc 600
tatgccattg cctcttccat cgtgtccttc tacgttcccc tggtgatcat ggtcttcgtc
660 tactccaggg tctttcagga ggccaaaagg cagctccaga agattgacaa
atctgagggc 720 cgcttccatg tccagaacct tagccaggtg gagcaggatg
ggcggacggg gcatggactc 780 cgcagatctt ccaagttctg cttgaaggag
cacaaagccc tcaagacgtt aggcatcatc 840 atgggcactt tcaccctctg
ctggctgccc ttcttcatcg ttaacattgt gcatgtgatc 900 caggataacc
tcatccgtaa ggaagtttac atcctcctaa attggatagg ctatgtcaat 960
tctggtttca atccccttat ctactgccgg agcccagatt tcaggattgc cttccaggag
1020 cttctgtgcc tgcgcaggtc ttctttgaag gcctatggca atggctactc
cagcaacggc 1080 aacacagggg agcagagtgg atatcacgtg gaacaggaga
aagaaaataa actgctgtgt 1140 gaagacctcc caggcacgga agactttgtg
ggccatcaag gtactgtgcc tagcgataac 1200 attgattcac aagggaggaa
ttgtagtaca aatgactcac tgctagagcg tggccagacg 1260 gtcaccaacc
tgcagtaata atcaaggagg ccctcgagat gggctgcctc gggaacagta 1320
agaccgagga ccagcgcaac gaggagaagg cgcagcgtga ggccaacaaa aagatcgaga
1380 agcagctgca gaaggacaag caggtctacc gggccacgca ccgcctgctg
ctgctgggtg 1440 ctggagaatc tggtaaaagc accattgtga agcagatgag
gatcctgcat gttaatgggt 1500 ttaatggaga cagtgagaag gcaaccaaag
tgcaggacat caaaaacaac ctgaaagagg 1560 cgattgaaac cattgtggcc
gccatgagca acctggtgcc ccccgtggag ctggccaacc 1620 ccgagaacca
gttcagagtg gactacatcc tgagtgtgat gaacgtgcct gactttgact 1680
tccctcccga attctatgag catgccaagg ctctgtggga ggatgaagga gtgcgtgcct
1740 gctacgaacg ctccaacgag taccagctga ttgactgtgc ccagtacttc
ctggacaaga 1800 tcgacgtgat caagcaggct gactatgtgc cgagcgatca
ggacctgctt cgctgccgtg 1860 tcctgacttc tggaatcttt gagaccaagt
tccaggtgga caaagtcaac ttccacatgt 1920 ttgacgtggg tggccagcgc
gatgaacgcc gcaagtggat ccagtgcttc aacgatgtga 1980 ctgccatcat
cttcgtggtg gccagcagca gctacaacat ggtcatccgg gaggacaacc 2040
agaccaaccg cctgcaggag gctctgaacc tcttcaagag catctggaac aacagatggc
2100 tgcgcaccat ctctgtgatc ctgttcctca acaagcaaga tctgctcgct
gagaaagtcc 2160 ttgctgggaa atcgaagatt gaggactact ttccagaatt
tgctcgctac actactcctg 2220 aggatgctac tcccgagccc ggagaggacc
cacgcgtgac ccgggccaag tacttcattc 2280 gagatgagtt tctgaggatc
agcactgcca gtggagatgg gcgtcactac tgctaccctc 2340 atttcacctg
cgctgtggac actgagaaca tccgccgtgt gttcaacgac tgccgtgaca 2400
tcattcagcg catgcacctt cgtcagtacg agctgctcat cgattaataa tctagaggat
2460 ccccgcgccc tcatccgaaa gggcg 2485 180 1146 DNA Homo sapien 180
ctcgagatgg gctgcctcgg gaacagtaag accgaggacc agcgcaacga ggagaaggcg
60 cagcgtgagg ccaacaaaaa gatcgagaag cagctgcaga aggacaagca
ggtctaccgg 120 gccacgcacc gcctgctgct gctgggtgct ggagaatctg
gtaaaagcac cattgtgaag 180 cagatgagga tcctgcatgt taatgggttt
aatggagaca gtgagaaggc aaccaaagtg 240 caggacatca aaaacaacct
gaaagaggcg attgaaacca ttgtggccgc catgagcaac 300 ctggtgcccc
ccgtggagct ggccaacccc gagaaccagt tcagagtgga ctacatcctg 360
agtgtgatga acgtgcctga ctttgacttc cctcccgaat tctatgagca tgccaaggct
420 ctgtgggagg atgaaggagt gcgtgcctgc tacgaacgct ccaacgagta
ccagctgatt 480 gactgtgccc agtacttcct ggacaagatc gacgtgatca
agcaggctga ctatgtgccg 540 agcgatcagg acctgcttcg ctgccgtgtc
ctgacttctg gaatctttga gaccaagttc 600 caggtggaca aagtcaactt
ccacatgttt gacgtgggtg gccagcgcga tgaacgccgc 660 aagtggatcc
agtgcttcaa cgatgtgact gccatcatct tcgtggtggc cagcagcagc 720
tacaacatgg tcatccggga ggacaaccag accaaccgcc tgcaggaggc tctgaacctc
780 ttcaagagca tctggaacaa cagatggctg cgcaccatct ctgtgatcct
gttcctcaac 840 aagcaagatc tgctcgctga gaaagtcctt gctgggaaat
cgaagattga ggactacttt 900 ccagaatttg ctcgctacac tactcctgag
gatgctactc ccgagcccgg agaggaccca 960 cgcgtgaccc gggccaagta
cttcattcga gatgagtttc tgaggatcag cactgccagt 1020 ggagatgggc
gtcactactg ctaccctcat ttcacctgcg ctgtggacac tgagaacatc 1080
cgccgtgtgt tcaacgactg ccgtgacatc attcagcgca tgcaccttcg tcagtacgag
1140 ctgctc 1146 181 1194 DNA Homo sapien 181 ctcgagatgg gctgcctcgg
gaacagtaag accgaggacc agcgcaacga ggagaaggcg 60 cagcgtgagg
ccaacaaaaa gatcgagaag cagctgcaga aggacaagca ggtctaccgg 120
gccacgcacc gcctgctgct gctgggtgct ggagaatctg gtaaaagcac cattgtgaag
180 cagatgagga tcctgcatgt taatgggttt aatggagagg gcggcgaaga
ggacccgcag 240 gctgcaagga gcaacagcga tggtgagaag gcaaccaaag
tgcaggacat caaaaacaac 300 ctgaaagagg cgattgaaac cattgtggcc
gccatgagca acctggtgcc ccccgtggag 360 ctggccaacc ccgagaacca
gttcagagtg gactacatcc tgagtgtgat gaacgtgcct 420 gactttgact
tccctcccga attctatgag catgccaagg ctctgtggga ggatgaagga 480
gtgcgtgcct gctacgaacg ctccaacgag taccagctga ttgactgtgc ccagtacttc
540 ctggacaaga tcgacgtgat caagcaggct gactatgtgc cgagcgatca
ggacctgctt 600 cgctgccgtg tcctgacttc tggaatcttt gagaccaagt
tccaggtgga caaagtcaac 660 ttccacatgt ttgacgtggg tggccagcgc
gatgaacgcc gcaagtggat ccagtgcttc 720 aacgatgtga ctgccatcat
cttcgtggtg gccagcagca gctacaacat ggtcatccgg 780 gaggacaacc
agaccaaccg cctgcaggag gctctgaacc tcttcaagag catctggaac 840
aacagatggc tgcgcaccat ctctgtgatc ctgttcctca acaagcaaga tctgctcgct
900 gagaaagtcc ttgctgggaa atcgaagatt gaggactact ttccagaatt
tgctcgctac 960 actactcctg aggatgctac tcccgagccc ggagaggacc
cacgcgtgac ccgggccaag 1020 tacttcattc gagatgagtt tctgaggatc
agcactgcca gtggagatgg gcgtcactac 1080 tgctaccctc atttcacctg
cgctgtggac actgagaaca tccgccgtgt gttcaacgac 1140 tgccgtgaca
tcattcagcg catgcacctt cgtcagtacg agctgctcat cgat 1194 182 1089 DNA
Homo sapien 182 ctcgagatga ctctggagtc catcatggcg tgctgcctga
gcgaggaggc caaggaagcc 60 cggcggatca acgacgagat cgagcggcag
ctccgcaggg acaagcggga cgcccgccgg 120 gagctcaagc tgctgctgct
cgggacagga gagagtggca agagtacgtt tatcaagcag 180 atgagaatca
tccatgggtc aggatactct gatgaagata aaaggggctt caccaagctg 240
gtgtatcaga acatcttcac ggccatgcag gccatgatca gagccatgga cacactcaag
300 atcccataca agtatgagca caataaggct catgcacaat tagttcgaga
agttgatgtg 360 gagaaggtgt ctgcttttga gaatccatat gtagatgcaa
taaagagttt atggaatgat 420 cctggaatcc aggaatgcta tgatagacga
cgagaatatc aattatctga ctctaccaaa 480 tactatctta atgacttgga
ccgcgtagct gaccctgcct acctgcctac gcaacaagat 540 gtgcttagag
ttcgagtccc caccacaggg atcatcgaat acccctttga cttacaaagt 600
gtcattttca gaatggtcga tgtagggggc caaaggtcag agagaagaaa atggatacac
660 tgctttgaaa atgtcacctc tatcatgttt ctagtagcgc ttagtgaata
tgatcaagtt 720 ctcgtggagt cagacaatga gaaccgaatg gaggaaagca
aggctctctt tagaacaatt 780 atcacatacc cctggttcca gaactcctcg
gttattctgt tcttaaacaa gaaagatctt 840 ctagaggaga aaatcatgta
ttcccatcta gtcgactact tcccagaata tgatggaccc 900 cagagagatg
cccaggcagc ccgagaattc attctgaaga tgttcgtgga cctgaaccca 960
gacagtgaca aaattatcta ctcccacttc acgtgcgcca cagacaccga gaatatccgc
1020 tttgtctttg ctgccgtcaa ggacaccatc ctccagttga acctgaagga
gtacaatctg 1080 gtcatcgat 1089 183 1077 DNA Homo sapien 183
ctcgagatgg gctgcaccgt gagcgccgag gacaaggcgg cggccgagcg ctctaagatg
60 atcgacaaga acctgcggga ggacggagag aaggcggcgc gggaggtgaa
gttgctgctg 120 ttgggtgctg gggagtcagg gaagagcacc atcgtcaagc
agatgaagat catccacgag 180 gatggctact ccgaggagga atgccggcag
taccgggcgg ttgtctacag caacaccatc 240 cagtccatca tggccattgt
caaagccatg ggaaacctgc agatcgactt tgccgacccc 300 tccagagcgg
acgacgccag gcagctattt gcactgtcct gcaccgccga ggagcaaggc 360
gtgctccctg atgacctgtc cggcgtcatc cggaggctct gggctgacca tggtgtgcag
420 gcctgctttg gccgctcaag ggaataccag ctcaacgact cagctgccta
ctacctgaac 480 gacctggagc gtattgcaca gagtgactac atccccacac
agcaagatgt gctacggacc 540 cgcgtaaaga ccacggggat cgtggagaca
cacttcacct tcaaggacct acacttcaag 600 atgtttgatg tgggtggtca
gcggtctgag cggaagaagt ggatccactg ctttgagggc 660 gtcacagcca
tcatcttctg cgtagccttg agcgcctatg acttggtgct agctgaggac 720
gaggagatga accgcatgca tgagagcatg aagctattcg atagcatctg caacaacaag
780 tggttcacag acacgtccat catcctcttc ctcaacaaga aggacctgtt
tgaggagaag 840 atcacacaca gtcccctgac catctgcttc cctgagtaca
caggggccaa caaatatgat 900 gaggcagcca gctacatcca gagtaagttt
gaggacctga ataagcgcaa agacaccaag 960 gagatctaca cgcacttcac
gtgcgccacc gacaccaaga acgtgcagtt cgtgtttgac 1020 gccgtcaccg
atgtcatcat caagaacaac ctgaaggact gcggcctctt catgcat 1077 184 1155
DNA Homo sapien 184 ctcgagatgt ccggggtggt gcggaccctc agccgctgcc
tgctgccggc cgaggccggc 60 ggggcccgcg agcgcagggc gggcagcggc
gcgcgcgacg cggagcgcga ggcccggagg 120 cgtagccgcg acatcgacgc
gctgctggcc cgcgagcggc gcgcggtccg gcgcctggtg 180 aagatcctgc
tgctgggcgc gggcgagagc ggcaagtcca cgttcctcaa gcagatgcgc 240
atcatccacg gccgcgagtt cgaccagaag gcgctgctgg agttccgcga caccatcttc
300 gacaacatcc tcaagggctc aagggttctt gttgatgcac gagataagct
tggcattcct 360 tggcagtatt ctgaaaatga gaagcatggg atgttcctga
tggccttcga gaacaaggcg 420 gggctgcctg tggagccggc caccttccag
ctgtacgtcc cggccctgag cgcactctgg 480 agggattctg gcatcaggga
ggctttcagc cggagaagcg agtttcagct gggggagtcg 540 gtgaagtact
tcctggacaa cttggaccgg atcggccagc tgaattactt tcctagtaag 600
caagatatcc tgctggctag gaaagccacc aagggaattg tggagcatga cttcgttatt
660 aagaagatcc cctttaagat ggtggatgtg ggcggccagc ggtcccagcg
ccagaagtgg 720 ttccagtgct tcgacgggat cacgtccatc ctgttcatgg
tctcctccag cgagtacgac 780 caggtcctca tggaggacag gcgcaccaac
cggctggtgg agtccatgaa catcttcgag 840 accatcgtca acaacaagct
cttcttcaac gtctccatca ttctcttcct caacaagatg 900 gacctcctgg
tggagaaggt gaagaccgtg agcatcaaga agcacttccc ggacttcagg 960
ggcgacccgc accagctgga ggacgtccag cgctacctgg tccagtgctt cgacaggaag
1020 agacggaacc gcagcaagcc actcttccac cacttcacca ccgccatcga
caccgagaac 1080 gtccgcttcg tgttccatgc tgtgaaagac accatcctgc
aggagaacct gaaggacatc 1140 atgctgcaga tcgat 1155 185 3307 DNA
Artificial Sequence Gene encoding a fusion protein 185 gtcgacatgg
ggcaacccgg gaacggcagc gccttcttgc tggcacccaa tggaagccat 60
gcgccggacc acgacgtcac gcagcaaagg gacgaggtgt gggtggtggg catgggcatc
120 gtcatgtctc tcatcgtcct ggccatcgtg tttggcaatg tgctggtcat
cacagccatt 180 gccaagttcg agcgtctgca gacggtcacc aactacttca
tcacttcact ggcctgtgct 240 gatctggtca tgggcctagc agtggtgccc
tttggggccg cccatattct tatgaaaatg 300 tggacttttg gcaacttctg
gtgcgagttt tggacttcca ttgatgtgct gtgcgtcacg 360 gccagcattg
agaccctgtg cgtgatcgca gtggatcgct actttgccat tacttcacct 420
ttcaagtacc agagcctgct gaccaagaat aaggcccggg tgatcattct gatggtgtgg
480 attgtgtcag gccttayctc cttcttgccc attcagatgc actggtacag
ggccacccac 540 caggaagcca tcaactgcta tgccaatgag acctgctgtg
acttcttcac gaaccaagcc 600 tatgccattg cctcttccat cgtgtccttc
tacgttcccc tggtgatcat ggtcttcgtc 660 tactccaggg tctttcagga
ggccaaaagg cagctccaga agattgacaa atctgagggc 720 cgcttccatg
tccagaacct tagccaggtg gagcaggatg ggcggacggg gcatggactc 780
cgcagatctt ccaagttctg cttgaaggag cacaaagccc tcaagacgtt aggcatcatc
840 atgggcactt tcaccctctg ctggctgccc ttcttcatcg ttaacattgt
gcatgtgatc 900 caggataacc tcatccgtaa ggaagtttac atcctcctaa
attggatagg ctatgtcaat 960 tctggtttca atccccttat ctactgccgg
agcccagatt tcaggattgc cttccaggag 1020 cttctgtgcc tgcgcaggtc
ttctttgaag gcctatggca atggctactc cagcaacggc 1080 aacacagggg
agcagagtgg atatcacgtg gaacaggaga aagaaaataa actgctgtgt 1140
gaagacctcc caggcacgga agactttgtg ggccatcaag gtactgtgcc tagcgataac
1200 attgattcac aagggaggaa ttgtagtaca aatgactcac tgctagagcg
tggccagacg 1260 gtcaccaacc tgcagggaca caactcaaaa gagatatcga
tgagtcatat tggtactaaa 1320 ttcattcttg ctgaaaaatt taccttcgat
cccctaagca atactctgat tgacaaagaa 1380 gatagtgaag agatcattcg
attaggcagc aacgaaagcc gaattctttg gctgctggcc 1440 caacgtccaa
acgaggtaat ttctcgcaat gatttgcatg actttgtttg gcgagagcaa 1500
ggttttgaag tcgatgattc cagcttaacc caagccattt cgactctgcg caaaatgctc
1560 aaagattcga caaagtcccc acaatacgtc aaaacggttc cgaagcgcgg
ttaccaattg 1620 atcgcccgag tggaaacggt tgaagaagag atggctcgcg
aaaacgaagc tgctcatgac 1680 atctcttaat aatcaaggag gccctcgaga
tgggctgcct cgggaacagt aagaccgagg 1740 accagcgcaa cgaggagaag
gcgcagcgtg aggccaacaa aaagatcgag aagcagctgc 1800 agaaggacaa
gcaggtctac cgggccacgc accgcctgct gctgctgggt gctggagaat 1860
ctggtaaaag caccattgtg aagcagatga ggatcctgca tgttaatggg tttaatggag
1920 acagtgagaa ggcaaccaaa gtgcaggaca tcaaaaacaa cctgaaagag
gcgattgaaa 1980 ccattgtggc cgccatgagc aacctggtgc cccccgtgga
gctggccaac cccgagaacc 2040 agttcagagt ggactacatc ctgagtgtga
tgaacgtgcc tgactttgac ttccctcccg 2100 aattctatga gcatgccaag
gctctgtggg aggatgaagg agtgcgtgcc tgctacgaac 2160 gctccaacga
gtaccagctg attgactgtg cccagtactt cctggacaag atcgacgtga 2220
tcaagcaggc tgactatgtg ccgagcgatc aggacctgct tcgctgccgt gtcctgactt
2280 ctggaatctt tgagaccaag ttccaggtgg acaaagtcaa cttccacatg
tttgacgtgg 2340 gtggccagcg cgatgaacgc cgcaagtgga tccagtgctt
caacgatgtg actgccatca 2400 tcttcgtggt ggccagcagc agctacaaca
tggtcatccg ggaggacaac cagaccaacc 2460 gcctgcagga ggctctgaac
ctcttcaaga gcatctggaa caacagatgg ctgcgcacca 2520 tctctgtgat
cctgttcctc aacaagcaag atctgctcgc tgagaaagtc cttgctggga 2580
aatcgaagat tgaggactac tttccagaat ttgctcgcta cactactcct gaggatgcta
2640 ctcccgagcc cggagaggac ccacgcgtga cccgggccaa gtacttcatt
cgagatgagt 2700 ttctgaggat cagcactgcc agtggagatg ggcgtcacta
ctgctaccct catttcacct 2760 gcgctgtgga cactgagaac atccgccgtg
tgttcaacga ctgccgtgac atcattcagc 2820 gcatgcacct tcgtcagtac
gagctgctca tcgatggaca caactcaaaa gagatatcga 2880 tgagtcatat
tggtactaaa ttcattcttg ctgaaaaatt taccttcgat cccctaagca 2940
atactctgat tgacaaagaa gatagtgaag agatcattcg attaggcagc aacgaaagcc
3000 gaattctttg gctgctggcc caacgtccaa acgaggtaat ttctcgcaat
gatttgcatg 3060 actttgtttg gcgagagcaa ggttttgaag tcgatgattc
cagcttaacc caagccattt 3120 cgactctgcg caaaatgctc aaagattcga
caaagtcccc acaatacgtc aaaacggttc 3180 cgaagcgcgg ttaccaattg
atcgcccgag tggaaacggt tgaagaagag atggctcgcg 3240 aaaacgaagc
tgctcatgac atctcttaat aatctagagg atccccgcgc cctcatccga 3300 aagggcg
3307 186 3284 DNA Artificial Sequence Gene encoding a fusion
protein 186 tctagaggct gtgggtagaa gtgaaacggg gtttaccgat aaaaacagaa
aatgataaaa 60 aaggactaaa tagtatattt tgatttttga tttttgattt
caaataatac aaatttattt 120 acttatttaa ttgttttgat caattatttt
tctgttaaac aaagggagca ttatatggta 180 aagaccatga ttacggattc
actggccgtc gttttacaac gtcgtgactg ggaaaaccct 240 ggcgttaccc
aacttaatcg ccttgcagca catccccctt tcgccagctg gcgtaatagc 300
gaagaggccc gcaccgatcg cccttcccaa cagttgcgca gcctgaatgg cgaatggcgc
360 tttgcctggt ttccggcacc agaagcggtg ccggaaagct ggctggagtg
cgatcttcct 420 gaggccgata ctgtcgtcgt cccctcaaac tggcagatgc
acggttacga tgcgcccatc 480 tacaccaacg tgacctatcc cattacggtc
aatccgccgt ttgttcccac ggagaatccg 540 acgggttgtt actcgctcac
atttaatgtt gatgaaagct ggctacagga aggccagacg 600 cgaattattt
ttgatggcgt taactcggcg tttcatctgt ggtgcaacgg gcgctgggtc 660
ggttacggcc aggacagtcg tttgccgtct gaatttgacc tgagcgcatt tttacgcgcc
720 ggagaaaacc gcctcgcggt gatggtgctg cgctggagtg acggcagtta
tctggaagat 780 caggatatgt ggcggatgag cggcattttc cgtgacgtct
cgttgctgca taaaccgact 840 acacaaatca gcgatttcca tgttgccact
cgctttaatg atgatttcag ccgcgctgta 900 ctggaggctg aagttcagat
gtgcggcgag ttgcgtgact acctacgggt aacagtttct 960 ttatggcagg
gtgaaacgca ggtcgccagc ggcaccgcgc ctttcggcgg tgaaattatc 1020
gatgagcgtg gtggttatgc cgatcgcgtc acactacgtc tgaacgtcga aaacccgaaa
1080 ctgtggagcg ccgaaatccc gaatctctat cgtgcggtgg ttgaactgca
caccgccgac 1140 ggcacgctga ttgaagcaga agcctgcgat gtcggtttcc
gcgaggtgcg gattgaaaat 1200 ggtctgctgc tgctgaacgg caagccgttg
ctgattcgag gcgttaaccg tcacgagcat 1260 catcctctgc atggtcaggt
catggatgag cagacgatgg tgcaggatat cctgctgatg 1320 aagcagaaca
actttaacgc cgtgcgctgt tcgcattatc cgaaccatcc gctgtggtac 1380
acgctgtgcg accgctacgg cctgtatgtg gtggatgaag ccaatattga aacccacggc
1440 atggtgccaa tgaatcgtct gaccgatgat ccgcgctggc taccggcgat
gagcgaacgc 1500 gtaacgcgaa tggtgcagcg cgatcgtaat cacccgagtg
tgatcatctg gtcgctgggg 1560 aatgaatcag gccacggcgc taatcacgac
gcgctgtatc gctggatcaa atctgtcgat 1620 ccttcccgcc cggtgcagta
tgaaggcggc ggagccgaca ccacggccac cgatattatt 1680 tgcccgatgt
acgcgcgcgt ggatgaagac cagcccttcc cggctgtgcc gaaatggtcc 1740
atcaaaaaat ggctttcgct acctggagag
acgcgcccgc tgatcctttg cgaatacgcc 1800 cacgcgatgg gtaacagtct
tggcggtttc gctaaatact ggcaggcgtt tcgtcagtat 1860 ccccgtttac
agggcggctt cgtctgggac tgggtggatc agtcgctgat taaatatgat 1920
gaaaacggca acccgtggtc ggcttacggc ggtgattttg gcgatacgcc gaacgatcgc
1980 cagttctgta tgaacggtct ggtctttgcc gaccgcacgc cgcatccagc
gctgacggaa 2040 gcaaaacacc agcagcagtt tttccagttc cgtttatccg
ggcaaaccat cgaagtgacc 2100 agcgaatacc tgttccgtca tagcgataac
gagctcctgc actggatggt ggcgctggat 2160 ggtaagccgc tggcaagcgg
tgaagtgcct ctggatgtcg ctccacaagg taaacagttg 2220 attgaactgc
ctgaactacc gcagccggag agcgccgggc aactctggct cacagtacgc 2280
gtagtgcaac cgaacgcgac cgcatggtca gaagccgggc acatcagcgc ctggcagcag
2340 tggcgtctgg cggaaaacct cagtgtgacg ctccccgccg cgtcccacgc
catcccgcat 2400 ctgaccacca gcgaaatgga tttttgcatc gagctgggta
ataagcgttg gcaatttaac 2460 cgccagtcag gctttctttc acagatgtgg
attggcgata aaaaacaact gctgacgccg 2520 ctgcgcgatc agttcacccg
tgcaccgctg gataacgaca ttggcgtaag tgaagcgacc 2580 cgcattgacc
ctaacgcctg ggtcgaacgc tggaaggcgg cgggccatta ccaggccgaa 2640
gcagcgttgt tgcagtgcac ggcagataca cttgctgatg cggtgctgat tacgaccgct
2700 cacgcgtggc agcatcaggg gaaaacctta tttatcagcc ggaaaaccta
ccggattgat 2760 ggtagtggtc aaatggcgat taccgttgat gttgaagtgg
cgagcgatac accgcatccg 2820 gcgcggattg gcctgaactg ccagctggcg
caggtagcag agcgggtaaa ctggctcgga 2880 ttagggccgc aagaaaacta
tcccgaccgc cttactgccg cctgttttga ccgctgggat 2940 ctgccattgt
cagacatgta taccccgtac gtcttcccga gcgaaaacgg tctgcgctgc 3000
gggacgcgcg aattgaatta tggcccacac cagtggcgcg gcgacttcca gttcaacatc
3060 agccgctaca gtcaacagca actgatggaa accagccatc gccatctgct
gcacgcggaa 3120 gaaggcacat ggctgaatat cgacggtttc catatgggga
ttggtggcga cgactcctgg 3180 agcccgtcag tatcggcgga attccagctg
agcgccggtc gctaccatta ccagttggtc 3240 tggtgtcaaa aataataacg
ccctcatccg aaagggcgtc taga 3284 187 25 DNA Artificial Sequence
Cloning primer 187 ggggcaaccc gggaacggca gcgcc 25 188 30 DNA
Artificial Sequence Cloning primer 188 gcagtgagtc atttgtacta
caattcctcc 30 189 37 DNA Artificial Sequence Cloning primer 189
cgcggtcgac atggggcaac ccgggaacgg cagcgcc 37 190 67 DNA Artificial
Sequence Cloning primer 190 ggctcgagct gcaggttggt gaccgtctgg
ccacgctcta gcagtgagtc atttgtacta 60 caattcc 67 191 29 DNA
Artificial Sequence Cloning primer 191 gggctgcctc gggaacagta
agaccgagg 29 192 29 DNA Artificial Sequence Cloning primer 192
gagcagctcg tactgacgaa ggtgcatgc 29 193 44 DNA Artificial Sequence
Cloning primer 193 ggaggccctc gagatgggct gcctcgggaa cagtaagacc gagg
44 194 48 DNA Artificial Sequence Cloning primer 194 cctctagatt
attatcgatg agcagctcgt actgacgaag gtgcatgc 48 195 37 DNA Artificial
Sequence Cloning primer 195 ccatcgatga gcagctcgta ctgacgaagg
tgcatgc 37 196 26 DNA Artificial Sequence Cloning primer 196
ccggggtggt gcggaccctc agccgc 26 197 28 DNA Artificial Sequence
Cloning primer 197 ctgcagcatg atgtccttca ggttctcc 28 198 41 DNA
Artificial Sequence Cloning primer 198 gcgggctcga gatgtccggg
gtggtgcgga ccctcagccg c 41 199 39 DNA Artificial Sequence Cloning
primer 199 gcgccatcga tctgcagcat gatgtccttc aggttctcc 39 200 28 DNA
Artificial Sequence Cloning primer 200 gactctggag tccatcatgg
cgtgctgc 28 201 29 DNA Artificial Sequence Cloning primer 201
ccagattgta ctccttcagg ttcaactgg 29 202 30 DNA Artificial Sequence
Cloning primer 202 atgactctgg agtccatcat ggcgtgctgc 30 203 42 DNA
Artificial Sequence Cloning primer 203 gcgccatcga tgaccagatt
gtactccttc aggttcaact gg 42 204 29 DNA Artificial Sequence Cloning
primer 204 gggctgcacc gtgagcgccg aggacaagg 29 205 30 DNA Artificial
Sequence Cloning primer 205 ccttcaggtt gttcttgatg atgacatcgg 30 206
31 DNA Artificial Sequence Cloning primer 206 atgggctgca ccgtgagcgc
cgaggacaag g 31 207 55 DNA Artificial Sequence Cloning primer 207
gcgccatcga tgaagaggcc gcagtccttc aggttgttct tgatgatgac atcgg 55 208
29 DNA Artificial Sequence Cloning primer 208 gggctgcctc gggaacagta
agaccgagg 29 209 29 DNA Artificial Sequence Cloning primer 209
gagcagctcg tactgacgaa ggtgcatgc 29 210 31 DNA Artificial Sequence
Cloning primer 210 atgggctgcc tcgggaacag taagaccgag g 31 211 40 DNA
Artificial Sequence Cloning primer 211 gcgccatcga tgagcagctc
gtactgacga aggtgcatgc 40 212 107 DNA Artificial Sequence Cloning
primer 212 ggctcgaggg cctccttgat tattactcga gggcctcctt gattattact
gcaggttggt 60 gaccgtctgg ccacgctcta gcagtgagtc atttgtacta caattcc
107 213 61 DNA Artificial Sequence Cloning primer 213 ccctgcaggt
tggtgaccgt ctggccacgc tctagcagtg agtcatttgt actacaattc 60 c 61 214
38 DNA Artificial Sequence Cloning primer 214 ggacacaact caaaagagat
atcgatgagt catattgg 38 215 29 DNA Artificial Sequence Cloning
primer 215 gagatgtcat gagcagcttc gttttcgcg 29 216 52 DNA Artificial
Sequence Cloning primer 216 gcgtggccag acggtcacca acctgcaggg
acacaactca aaagagatat cg 52 217 51 DNA Artificial Sequence Primer
217 cggggatcct ctagattatt aagagatgtc atgagcagct tcgttttcgc g 51 218
32 DNA Artificial Sequence Cloning primer 218 ggctgtgggt agaagtgaaa
cggggtttac cg 32 219 32 DNA Artificial Sequence Cloning primer 219
ctttaccata taatgctccc tttgtttaac ag 32 220 43 DNA Artificial
Sequence Cloning primer 220 cgcggtctag aggctgtggg tagaagtgaa
acggggttta ccg 43 221 60 DNA Artificial Sequence Cloning primer 221
cgacggccag tgaatccgta atcatggtct ttaccatata atgctccctt tgtttaacag
60 222 27 DNA Artificial Sequence Cloning primer 222 ccatgattac
ggattcactg gccgtcg 27 223 27 DNA Artificial Sequence Cloning primer
223 ccagaccaac tggtaatggt agcgacc 27 224 35 DNA Artificial Sequence
Cloning primer 224 ggtaaagacc atgattacgg attcactggc cgtcg 35 225 77
DNA Artificial Sequence Cloning primer 225 gcgcctctag aaatacgccc
tttcggatga gggcgttatt atttttgaca ccagaccaac 60 tggtaatggt agcgacc
77 226 89 DNA Artificial Sequence Cloning primer 226 cgcggatgca
tatgaaaata aaaacaggtg cacgcatcct cgcattatcc gcattaacga 60
cgatgatgtt ttccgcctcg gctctcgcc 89 227 69 DNA Artificial Sequence
Cloning primer 227 cgtcgaccga ggcctgcagg cgggcttcga tgattttggc
gagagccgag gcggaaaaca 60 tcatcgtcg 69 228 81 DNA Artificial
Sequence Cloning primer 228 cgaagcccgc ctgcaggcct cggtcgacgc
cgaatctaga gattataaag atgacgatga 60 caaataataa gctagcggcg c 81 229
27 DNA Artificial Sequence Cloning primer 229 gcgccgctag cttattattt
gtcatcg 27 230 26 DNA Artificial Sequence Cloning primer 230
ggtgcacgca tcctcgcatt atccgc 26 231 30 DNA Artificial Sequence
Cloning primer 231 ggcgttttcc atggtggcgg caatacgtgg 30 232 52 DNA
Artificial Sequence Cloning primer 232 cgcggatgca tatgaaaata
aaaacaggtg cacgcatcct cgcattatcc gc 52 233 82 DNA Artificial
Sequence Cloning primer 233 ccgaggcctg caggcgggct tcgatacgca
cggcatacca gaaagcggac tgggcgtttt 60 ccatggtggc ggcaatacgt gg 82 234
87 DNA Artificial Sequence Cloning primer 234 gcgccgctag cttattattt
gtcatcgtca tctttataat ctctagattc ggcgtcgacc 60 gaggcctgca
ggcgggcttc gatacgc 87 235 26 DNA Artificial Sequence Cloning primer
235 cctgactgac gacagttttg acacgg 26 236 32 DNA Artificial Sequence
Cloning primer 236 cctttagaca gtgcacccac tttggttgcc gc 32 237 78
DNA Artificial Sequence Cloning primer 237 cgcggctgca ggcctcggtc
gacgccgaat ctagaagcga taaaattatt cacctgactg 60 acgacagttt tgacacgg
78 238 95 DNA Artificial Sequence Cloning primer 238 gcgccgctag
cttattattt gtcatcgtca tctttataat ccgccaggtt ctctttcaac 60
tgacctttag acagtgcacc cactttggtt gccgc 95 239 216 DNA Artificial
Sequence Fusion vector 239 gaattcaggc gctttttaga ctggtcgtaa
tgaaattcag gaggttctgc atatgaaaat 60 aaaaacaggt gcacgcatcc
tcgcattatc cgcattaacg acgatgatgt tttccgcctc 120 ggctctcgcc
aaaatcatcg aagcccgcct gcaggcctcg gtcgacgccg aatctagaga 180
ttataaagat gacgatgaca aataataagc tagagg 216 240 202 DNA Artificial
Sequence Fusion vector 240 ccatacccgt ttttttgggc tagcaggagg
ccctgcatat gaaaataaaa acaggtgcac 60 gcatcctcgc attatccgca
ttaacgacga tgatgttttc cgcctcggct ctcgccaaaa 120 tcatcgaagc
ccgcctgcag gcctcggtcg acgccgaatc tagagattat aaagatgacg 180
atgacaaata ataagctaga gg 202 241 182 DNA Artificial Sequence Fusion
vector 241 aggaggttct gcatatgaaa ataaaaacag gtgcacgcat cctcgcatta
tccgcattaa 60 cgacgatgat gttttccgcc tcggctctcg ccaaaatcat
cgaagcccgc ctgcaggcct 120 cggtcgacgc cgaatctaga gattataaag
atgacgatga caaataataa gctagaggta 180 cc 182 242 182 DNA Artificial
Sequence Fusion vector 242 aggaggttct gcatatgaaa ataaaaacag
gtgcacgcat cctcgcatta tccgcattaa 60 cgacgatgat gttttccgcc
tcggctctcg ccaaaatcat cgaagcccgc ctgcaggcct 120 cggtcgacgc
cgaatctaga gattataaag atgacgatga caaataataa gctagaggta 180 cc 182
243 1080 DNA Artificial Sequence Fusion vector 243 gaattcaggc
gctttttaga ctggtcgtaa tgaaattcag gaggttctgc atatgaaaat 60
aaaaacaggt gcacgcatcc tcgcattatc cgcattaacg acgatgatgt tttccgcctc
120 ggctctcgcc aaaatcgaag aaggtaaact ggtaatctgg attaacggcg
ataaaggcta 180 taacggtctc gctgaagtcg gtaagaaatt cgagaaagat
accggaatta aagtcaccgt 240 tgagcatccg gataaactgg aagagaaatt
cccacaggtt gcggcaactg gcgatggccc 300 tgacattatc ttctgggcac
acgaccgctt tggtggctac gctcaatctg gcctgttggc 360 tgaaatcacc
ccggacaaag cgttccagga caagctgtat ccgtttacct gggatgccgt 420
acgttacaac ggcaagctga ttgcttaccc gatcgctgtt gaagcgttat cgctgattta
480 taacaaagat ctgctgccga acccgccaaa aacctgggaa gagatcccgg
cgctggataa 540 agaactgaaa gcgaaaggta agagcgcgct gatgttcaac
ctgcaagaac cgtacttcac 600 ctggccgctg attgctgctg acgggggtta
tgcgttcaag tatgaaaacg gcaagtacga 660 cattaaagac gtgggcgtgg
ataacgctgg cgcgaaagcg ggtctgacct tcctggttga 720 cctgattaaa
aacaaacaca tgaatgcaga caccgattac tccatcgcag aagctgcctt 780
taataaaggc gaaacagcga tgaccatcaa cggcccgtgg gcatggtcca acatcgacac
840 cagcaaagtg aattatggtg taacggtact gccgaccttc aagggtcaac
catccaaacc 900 gttcgttggc gtgctgagcg caggtattaa cgccgccagt
ccgaacaaag agctggcgaa 960 agagttcctc gaaaactatc tgctgactga
tgaaggtctg gaagcggtta ataaagacaa 1020 accgctgggt gccgtagcgc
tgaagtctta cgaggaagag ttggcgaaag atccacgtat 1080 244 1196 DNA
Artificial Sequence Fusion vector 244 ccatacccgt ttttttgggc
tagcaggagg ccctgcatat gaaaataaaa acaggtgcac 60 gcatcctcgc
attatccgca ttaacgacga tgatgttttc cgcctcggct ctcgccaaaa 120
tcgaagaagg taaactggta atctggatta acggcgataa aggctataac ggtctcgctg
180 aagtcggtaa gaaattcgag aaagataccg gaattaaagt caccgttgag
catccggata 240 aactggaaga gaaattccca caggttgcgg caactggcga
tggccctgac attatcttct 300 gggcacacga ccgctttggt ggctacgctc
aatctggcct gttggctgaa atcaccccgg 360 acaaagcgtt ccaggacaag
ctgtatccgt ttacctggga tgccgtacgt tacaacggca 420 agctgattgc
ttacccgatc gctgttgaag cgttatcgct gatttataac aaagatctgc 480
tgccgaaccc gccaaaaacc tgggaagaga tcccggcgct ggataaagaa ctgaaagcga
540 aaggtaagag cgcgctgatg ttcaacctgc aagaaccgta cttcacctgg
ccgctgattg 600 ctgctgacgg gggttatgcg ttcaagtatg aaaacggcaa
gtacgacatt aaagacgtgg 660 gcgtggataa cgctggcgcg aaagcgggtc
tgaccttcct ggttgacctg attaaaaaca 720 aacacatgaa tgcagacacc
gattactcca tcgcagaagc tgcctttaat aaaggcgaaa 780 cagcgatgac
catcaacggc ccgtgggcat ggtccaacat cgacaccagc aaagtgaatt 840
atggtgtaac ggtactgccg accttcaagg gtcaaccatc caaaccgttc gttggcgtgc
900 tgagcgcagg tattaacgcc gccagtccga acaaagagct ggcgaaagag
ttcctcgaaa 960 actatctgct gactgatgaa ggtctggaag cggttaataa
agacaaaccg ctgggtgccg 1020 tagcgctgaa gtcttacgag gaagagttgg
cgaaagatcc acgtattgcc gccaccatgg 1080 aaaacgccca gtccgctttc
tggtatgccg tgcgtatcga agcccgcctg caggcctcgg 1140 tcgacgccga
atctagagat tataaagatg acgatgacaa ataataagct agagga 1196 245 1171
DNA Artificial Sequence Fusion vector 245 aggaggttct gcatatgaaa
ataaaaacag gtgcacgcat cctcgcatta tccgcattaa 60 cgacgatgat
gttttccgcc tcggctctcg ccaaaatcga agaaggtaaa ctggtaatct 120
ggattaacgg cgataaaggc tataacggtc tcgctgaagt cggtaagaaa ttcgagaaag
180 ataccggaat taaagtcacc gttgagcatc cggataaact ggaagagaaa
ttcccacagg 240 ttgcggcaac tggcgatggc cctgacatta tcttctgggc
acacgaccgc tttggtggct 300 acgctcaatc tggcctgttg gctgaaatca
ccccggacaa agcgttccag gacaagctgt 360 atccgtttac ctgggatgcc
gtacgttaca acggcaagct gattgcttac ccgatcgctg 420 ttgaagcgtt
atcgctgatt tataacaaag atctgctgcc gaacccgcca aaaacctggg 480
aagagatccc ggcgctggat aaagaactga aagcgaaagg taagagcgcg ctgatgttca
540 acctgcaaga accgtacttc acctggccgc tgattgctgc tgacgggggt
tatgcgttca 600 agtatgaaaa cggcaagtac gacattaaag acgtgggcgt
ggataacgct ggcgcgaaag 660 cgggtctgac cttcctggtt gacctgatta
aaaacaaaca catgaatgca gacaccgatt 720 actccatcgc agaagctgcc
tttaataaag gcgaaacagc gatgaccatc aacggcccgt 780 gggcatggtc
caacatcgac accagcaaag tgaattatgg tgtaacggta ctgccgacct 840
tcaagggtca accatccaaa ccgttcgttg gcgtgctgag cgcaggtatt aacgccgcca
900 gtccgaacaa agagctggcg aaagagttcc tcgaaaacta tctgctgact
gatgaaggtc 960 tggaagcggt taataaagac aaaccgctgg gtgccgtagc
gctgaagtct tacgaggaag 1020 agttggcgaa agatccacgt attgccgcca
ccatggaaaa cgcccagtcc gctttctggt 1080 atgccgtgcg tatcgaagcc
cgcctgcagg cctcggtcga cgccgaatct agagattata 1140 aagatgacga
tgacaaataa taagctagag g 1171 246 1171 DNA Artificial Sequence
Fusion vector 246 aggaggttct gcatatgaaa ataaaaacag gtgcacgcat
cctcgcatta tccgcattaa 60 cgacgatgat gttttccgcc tcggctctcg
ccaaaatcga agaaggtaaa ctggtaatct 120 ggattaacgg cgataaaggc
tataacggtc tcgctgaagt cggtaagaaa ttcgagaaag 180 ataccggaat
taaagtcacc gttgagcatc cggataaact ggaagagaaa ttcccacagg 240
ttgcggcaac tggcgatggc cctgacatta tcttctgggc acacgaccgc tttggtggct
300 acgctcaatc tggcctgttg gctgaaatca ccccggacaa agcgttccag
gacaagctgt 360 atccgtttac ctgggatgcc gtacgttaca acggcaagct
gattgcttac ccgatcgctg 420 ttgaagcgtt atcgctgatt tataacaaag
atctgctgcc gaacccgcca aaaacctggg 480 aagagatccc ggcgctggat
aaagaactga aagcgaaagg taagagcgcg ctgatgttca 540 acctgcaaga
accgtacttc acctggccgc tgattgctgc tgacgggggt tatgcgttca 600
agtatgaaaa cggcaagtac gacattaaag acgtgggcgt ggataacgct ggcgcgaaag
660 cgggtctgac cttcctggtt gacctgatta aaaacaaaca catgaatgca
gacaccgatt 720 actccatcgc agaagctgcc tttaataaag gcgaaacagc
gatgaccatc aacggcccgt 780 gggcatggtc caacatcgac accagcaaag
tgaattatgg tgtaacggta ctgccgacct 840 tcaagggtca accatccaaa
ccgttcgttg gcgtgctgag cgcaggtatt aacgccgcca 900 gtccgaacaa
agagctggcg aaagagttcc tcgaaaacta tctgctgact gatgaaggtc 960
tggaagcggt taataaagac aaaccgctgg gtgccgtagc gctgaagtct tacgaggaag
1020 agttggcgaa agatccacgt attgccgcca ccatggaaaa cgcccagtcc
gctttctggt 1080 atgccgtgcg tatcgaagcc cgcctgcagg cctcggtcga
cgccgaatct agagattata 1140 aagatgacga tgacaaataa taagctagag g 1171
247 392 DNA Artificial Sequence Fusion vector 247 tagcaggagg
ccctgcaggc ctcggtcgac gccgaatcta gaagcgataa aattattcac 60
ctgactgacg acagttttga cacggatgta ctcaaagcgg acggggcgat cctcgtcgat
120 ttctgggcag agtggtgcgg tccgtgcaaa atgatcgccc cgattctgga
tgaaatcgct 180 gacgaatatc agggcaaact gaccgttgca aaactgaaca
tcgatcaaaa ccctggcact 240 gcgccgaaat atggcatccg tggtatcccg
actctgctgc tgttcaaaaa cggtgaagtg 300 gcggcaacca aagtgggtgc
actgtctaaa ggtcagttga aagagaacct ggcggattat 360 aaagatgacg
atgacaaata ataagctaga gg 392 248 426 DNA Artificial Sequence Fusion
vector 248 gaattcaggc gctttttaga ctggtcgtaa tgaaattcag gaggttctgc
aggcctcggt 60 cgacgccgaa tctagaagcg ataaaattat tcacctgact
gacgacagtt ttgacacgga 120 tgtactcaaa gcggacgggg cgatcctcgt
cgatttctgg gcagagtggt gcggtccgtg 180 caaaatgatc gccccgattc
tggatgaaat cgctgacgaa tatcagggca aactgaccgt 240 tgcaaaactg
aacatcgatc aaaaccctgg cactgcgccg aaatatggca tccgtggtat 300
cccgactctg ctgctgttca aaaacggtga agtggcggca accaaagtgg gtgcactgtc
360 taaaggtcag ttgaaagaga acctggcgga ttataaagat gacgatgaca
aataataagc 420 tagagg 426 249 392 DNA Artificial Sequence Fusion
vector 249 aggaggttct gcaggcctcg gtcgacgccg aatctagaag cgataaaatt
attcacctga 60 ctgacgacag ttttgacacg gatgtactca aagcggacgg
ggcgatcctc gtcgatttct 120 gggcagagtg gtgcggtccg tgcaaaatga
tcgccccgat tctggatgaa atcgctgacg 180 aatatcaggg caaactgacc
gttgcaaaac tgaacatcga tcaaaaccct ggcactgcgc 240 cgaaatatgg
catccgtggt atcccgactc tgctgctgtt caaaaacggt gaagtggcgg 300
caaccaaagt gggtgcactg tctaaaggtc agttgaaaga gaacctggcg gattataaag
360 atgacgatga caaataataa gctagaggta cc 392 250 392 DNA Artificial
Sequence Fusion vector 250 aggaggttct gcaggcctcg gtcgacgccg
aatctagaag cgataaaatt attcacctga 60 ctgacgacag ttttgacacg
gatgtactca aagcggacgg ggcgatcctc gtcgatttct 120 gggcagagtg
gtgcggtccg tgcaaaatga tcgccccgat tctggatgaa atcgctgacg 180
aatatcaggg caaactgacc gttgcaaaac tgaacatcga tcaaaaccct ggcactgcgc
240 cgaaatatgg catccgtggt atcccgactc tgctgctgtt caaaaacggt
gaagtggcgg 300 caaccaaagt gggtgcactg tctaaaggtc agttgaaaga
gaacctggcg gattataaag 360 atgacgatga caaataataa gctagaggta cc 392
251 528 DNA Artificial Sequence Gene encoding a fusion protein 251
gaattcaggc gctttttaga ctggtcgtaa tgaaattcag gaggttctgc atatgaaaat
60 aaaaacaggt gcacgcatcc tcgcattatc cgcattaacg acgatgatgt
tttccgcctc 120 ggctctcgcc aaaatcatcg aagcccgcct gcaggcctcg
gtcgacgccg aatctagaag 180 cgataaaatt attcacctga ctgacgacag
ttttgacacg gatgtactca aagcggacgg 240 ggcgatcctc gtcgatttct
gggcagagtg gtgcggtccg tgcaaaatga tcgccccgat 300 tctggatgaa
atcgctgacg aatatcaggg caaactgacc gttgcaaaac tgaacatcga 360
tcaaaaccct ggcactgcgc cgaaatatgg catccgtggt atcccgactc tgctgctgtt
420 caaaaacggt gaagtggcgg caaccaaagt gggtgcactg tctaaaggtc
agttgaaaga 480 gaacctggcg gattataaag atgacgatga caaataataa gctagagg
528 252 514 DNA Artificial Sequence Gene encoding a fusion protein
252 ccatacccgt ttttttgggc tagcaggagg ccctgcatat gaaaataaaa
acaggtgcac 60 gcatcctcgc attatccgca ttaacgacga tgatgttttc
cgcctcggct ctcgccaaaa 120 tcatcgaagc ccgcctgcag gcctcggtcg
acgccgaatc tagaagcgat aaaattattc 180 acctgactga cgacagtttt
gacacggatg tactcaaagc ggacggggcg atcctcgtcg 240 atttctgggc
agagtggtgc ggtccgtgca aaatgatcgc cccgattctg gatgaaatcg 300
ctgacgaata tcagggcaaa ctgaccgttg caaaactgaa catcgatcaa aaccctggca
360 ctgcgccgaa atatggcatc cgtggtatcc cgactctgct gctgttcaaa
aacggtgaag 420 tggcggcaac caaagtgggt gcactgtcta aaggtcagtt
gaaagagaac ctggcggatt 480 ataaagatga cgatgacaaa taataagcta gagg 514
253 494 DNA Artificial Sequence Gene encoding a fusion protein 253
aggaggttct gcatatgaaa ataaaaacag gtgcacgcat cctcgcatta tccgcattaa
60 cgacgatgat gttttccgcc tcggctctcg ccaaaatcat cgaagcccgc
ctgcaggcct 120 cggtcgacgc cgaatctaga agcgataaaa ttattcacct
gactgacgac agttttgaca 180 cggatgtact caaagcggac ggggcgatcc
tcgtcgattt ctgggcagag tggtgcggtc 240 cgtgcaaaat gatcgccccg
attctggatg aaatcgctga cgaatatcag ggcaaactga 300 ccgttgcaaa
actgaacatc gatcaaaacc ctggcactgc gccgaaatat ggcatccgtg 360
gtatcccgac tctgctgctg ttcaaaaacg gtgaagtggc ggcaaccaaa gtgggtgcac
420 tgtctaaagg tcagttgaaa gagaacctgg cggattataa agatgacgat
gacaaataat 480 aagctagagg tacc 494 254 494 DNA Artificial Sequence
Gene encoding a fusion protein 254 aggaggttct gcatatgaaa ataaaaacag
gtgcacgcat cctcgcatta tccgcattaa 60 cgacgatgat gttttccgcc
tcggctctcg ccaaaatcat cgaagcccgc ctgcaggcct 120 cggtcgacgc
cgaatctaga agcgataaaa ttattcacct gactgacgac agttttgaca 180
cggatgtact caaagcggac ggggcgatcc tcgtcgattt ctgggcagag tggtgcggtc
240 cgtgcaaaat gatcgccccg attctggatg aaatcgctga cgaatatcag
ggcaaactga 300 ccgttgcaaa actgaacatc gatcaaaacc ctggcactgc
gccgaaatat ggcatccgtg 360 gtatcccgac tctgctgctg ttcaaaaacg
gtgaagtggc ggcaaccaaa gtgggtgcac 420 tgtctaaagg tcagttgaaa
gagaacctgg cggattataa agatgacgat gacaaataat 480 aagctagagg tacc 494
255 1521 DNA Artificial Sequence Gene encoding a fusion protein 255
gaattcaggc gctttttaga ctggtcgtaa tgaaattcag gaggttctgc atatgaaaat
60 aaaaacaggt gcacgcatcc tcgcattatc cgcattaacg acgatgatgt
tttccgcctc 120 ggctctcgcc aaaatcgaag aaggtaaact ggtaatctgg
attaacggcg ataaaggcta 180 taacggtctc gctgaagtcg gtaagaaatt
cgagaaagat accggaatta aagtcaccgt 240 tgagcatccg gataaactgg
aagagaaatt cccacaggtt gcggcaactg gcgatggccc 300 tgacattatc
ttctgggcac acgaccgctt tggtggctac gctcaatctg gcctgttggc 360
tgaaatcacc ccggacaaag cgttccagga caagctgtat ccgtttacct gggatgccgt
420 acgttacaac ggcaagctga ttgcttaccc gatcgctgtt gaagcgttat
cgctgattta 480 taacaaagat ctgctgccga acccgccaaa aacctgggaa
gagatcccgg cgctggataa 540 agaactgaaa gcgaaaggta agagcgcgct
gatgttcaac ctgcaagaac cgtacttcac 600 ctggccgctg attgctgctg
acgggggtta tgcgttcaag tatgaaaacg gcaagtacga 660 cattaaagac
gtgggcgtgg ataacgctgg cgcgaaagcg ggtctgacct tcctggttga 720
cctgattaaa aacaaacaca tgaatgcaga caccgattac tccatcgcag aagctgcctt
780 taataaaggc gaaacagcga tgaccatcaa cggcccgtgg gcatggtcca
acatcgacac 840 cagcaaagtg aattatggtg taacggtact gccgaccttc
aagggtcaac catccaaacc 900 gttcgttggc gtgctgagcg caggtattaa
cgccgccagt ccgaacaaag agctggcgaa 960 agagttcctc gaaaactatc
tgctgactga tgaaggtctg gaagcggtta ataaagacaa 1020 accgctgggt
gccgtagcgc tgaagtctta cgaggaagag ttggcgaaag atccacgtat 1080
tgccgccacc atggaaaacg cccagtccgc tttctggtat gccgtgcgta tcgaagcccg
1140 cctgcaggcc tcggtcgacg ccgaatctag aagcgataaa attattcacc
tgactgacga 1200 cagttttgac acggatgtac tcaaagcgga cggggcgatc
ctcgtcgatt tctgggcaga 1260 gtggtgcggt ccgtgcaaaa tgatcgcccc
gattctggat gaaatcgctg acgaatatca 1320 gggcaaactg accgttgcaa
aactgaacat cgatcaaaac cctggcactg cgccgaaata 1380 tggcatccgt
ggtatcccga ctctgctgct gttcaaaaac ggtgaagtgg cggcaaccaa 1440
agtgggtgca ctgtctaaag gtcagttgaa agagaacctg gcggattata aagatgacga
1500 tgacaaataa taagctagag g 1521 256 1500 DNA Artificial Sequence
Gene encoding a fusion protein 256 ccatacccgt ttttttgggc tagcaggagg
ccctgcatat gaaaataaaa acaggtgcac 60 gcatcctcgc attatccgca
ttaacgacga tgatgttttc cgcctcggct ctcgccaaaa 120 tcgaagaagg
taaactggta atctggatta acggcgataa aggctataac ggtctcgctg 180
aagtcggtaa gaaattcgag aaagataccg gaattaaagt caccgttgag catccggata
240 aactggaaga gaaattccca caggttgcgg caactggcga tggccctgac
attatcttct 300 gggcacacga ccgctttggt ggctacgctc aatctggcct
gttggctgaa atcaccccgg 360 acaaagcgtt ccaggacaag ctgtatccgt
ttacctggga tgccgtacgt tacaacggca 420 agctgattgc ttacccgatc
gctgttgaag cgttatcgct gatttataac aaagatctgc 480 tgccgaaccc
gccaaaaacc tgggaagaga tcccggcgct ggataaagaa ctgaaagcga 540
aaggtaagag cgcgctgatg ttcaacctgc aagaaccgta cttcacctgg ccgctgattg
600 ctgctgacgg gggttatgcg ttcaagtatg aaaacggcaa gtacgacatt
aaagacgtgg 660 gcgtggataa cgctggcgcg aaagcgggtc tgaccttcct
ggttgacctg attaaaaaca 720 aacacatgaa tgcagacacc gattactcca
tcgcagaagc tgcctttaat aaaggcgaaa 780 cagcgatgac catcaacggc
ccgtgggcat ggtccaacat cgacaccagc aaagtgaatt 840 atggtgtaac
ggtactgccg accttcaagg gtcaaccatc caaaccgttc gttggcgtgc 900
tgagcgcagg tattaacgcc gccagtccga acaaagagct ggcgaaagag ttcctcgaaa
960 actatctgct gactgatgaa ggtctggaag cggttaataa agacaaaccg
ctgggtgccg 1020 tagcgctgaa gtcttacgag gaagagttgg cgaaagatcc
acgtattgcc gccaccatgg 1080 aaaacgccca gtccgctttc tggtatgccg
tgcgtatcga agcccgcctg caggcctcgg 1140 tcgacgccga atctagaagc
gataaaatta ttcacctgac tgacgacagt tttgacacgg 1200 atgtactcaa
agcggacggg gcgatcctcg tcgatttctg ggcagagtgg tgcggtccgt 1260
gcaaaatgat cgccccgatt ctggatgaaa tcgctgacga atatcagggc aaactgaccg
1320 ttgcaaaact gaacatcgat caaaaccctg gcactgcgcc gaaatatggc
atccgtggta 1380 tcccgactct gctgctgttc aaaaacggtg aagtggcggc
aaccaaagtg ggtgcactgt 1440 ctaaaggtca gttgaaagag aacctggcgg
attataaaga tgacgatgac aaataataag 1500 257 1476 DNA Artificial
Sequence Gene encoding a fusion protein 257 aggaggttct gcatatgaaa
ataaaaacag gtgcacgcat cctcgcatta tccgcattaa 60 cgacgatgat
gttttccgcc tcggctctcg ccaaaatcga agaaggtaaa ctggtaatct 120
ggattaacgg cgataaaggc tataacggtc tcgctgaagt cggtaagaaa ttcgagaaag
180 ataccggaat taaagtcacc gttgagcatc cggataaact ggaagagaaa
ttcccacagg 240 ttgcggcaac tggcgatggc cctgacatta tcttctgggc
acacgaccgc tttggtggct 300 acgctcaatc tggcctgttg gctgaaatca
ccccggacaa agcgttccag gacaagctgt 360 atccgtttac ctgggatgcc
gtacgttaca acggcaagct gattgcttac ccgatcgctg 420 ttgaagcgtt
atcgctgatt tataacaaag atctgctgcc gaacccgcca aaaacctggg 480
aagagatccc ggcgctggat aaagaactga aagcgaaagg taagagcgcg ctgatgttca
540 acctgcaaga accgtacttc acctggccgc tgattgctgc tgacgggggt
tatgcgttca 600 agtatgaaaa cggcaagtac gacattaaag acgtgggcgt
ggataacgct ggcgcgaaag 660 cgggtctgac cttcctggtt gacctgatta
aaaacaaaca catgaatgca gacaccgatt 720 actccatcgc agaagctgcc
tttaataaag gcgaaacagc gatgaccatc aacggcccgt 780 gggcatggtc
caacatcgac accagcaaag tgaattatgg tgtaacggta ctgccgacct 840
tcaagggtca accatccaaa ccgttcgttg gcgtgctgag cgcaggtatt aacgccgcca
900 gtccgaacaa agagctggcg aaagagttcc tcgaaaacta tctgctgact
gatgaaggtc 960 tggaagcggt taataaagac aaaccgctgg gtgccgtagc
gctgaagtct tacgaggaag 1020 agttggcgaa agatccacgt attgccgcca
ccatggaaaa cgcccagtcc gctttctggt 1080 atgccgtgcg tatcgaagcc
cgcctgcagg cctcggtcga cgccgaatct agaagcgata 1140 aaattattca
cctgactgac gacagttttg acacggatgt actcaaagcg gacggggcga 1200
tcctcgtcga tttctgggca gagtggtgcg gtccgtgcaa aatgatcgcc ccgattctgg
1260 atgaaatcgc tgacgaatat cagggcaaac tgaccgttgc aaaactgaac
atcgatcaaa 1320 accctggcac tgcgccgaaa tatggcatcc gtggtatccc
gactctgctg ctgttcaaaa 1380 acggtgaagt ggcggcaacc aaagtgggtg
cactgtctaa aggtcagttg aaagagaacc 1440 tggcggatta taaagatgac
gatgacaaat aataag 1476 258 1476 DNA Artificial Sequence Gene
encoding a fusion protein 258 aggaggttct gcatatgaaa ataaaaacag
gtgcacgcat cctcgcatta tccgcattaa 60 cgacgatgat gttttccgcc
tcggctctcg ccaaaatcga agaaggtaaa ctggtaatct 120 ggattaacgg
cgataaaggc tataacggtc tcgctgaagt cggtaagaaa ttcgagaaag 180
ataccggaat taaagtcacc gttgagcatc cggataaact ggaagagaaa ttcccacagg
240 ttgcggcaac tggcgatggc cctgacatta tcttctgggc acacgaccgc
tttggtggct 300 acgctcaatc tggcctgttg gctgaaatca ccccggacaa
agcgttccag gacaagctgt 360 atccgtttac ctgggatgcc gtacgttaca
acggcaagct gattgcttac ccgatcgctg 420 ttgaagcgtt atcgctgatt
tataacaaag atctgctgcc gaacccgcca aaaacctggg 480 aagagatccc
ggcgctggat aaagaactga aagcgaaagg taagagcgcg ctgatgttca 540
acctgcaaga accgtacttc acctggccgc tgattgctgc tgacgggggt tatgcgttca
600 agtatgaaaa cggcaagtac gacattaaag acgtgggcgt ggataacgct
ggcgcgaaag 660 cgggtctgac cttcctggtt gacctgatta aaaacaaaca
catgaatgca gacaccgatt 720 actccatcgc agaagctgcc tttaataaag
gcgaaacagc gatgaccatc aacggcccgt 780 gggcatggtc caacatcgac
accagcaaag tgaattatgg tgtaacggta ctgccgacct 840 tcaagggtca
accatccaaa ccgttcgttg gcgtgctgag cgcaggtatt aacgccgcca 900
gtccgaacaa agagctggcg aaagagttcc tcgaaaacta tctgctgact gatgaaggtc
960 tggaagcggt taataaagac aaaccgctgg gtgccgtagc gctgaagtct
tacgaggaag 1020 agttggcgaa agatccacgt attgccgcca ccatggaaaa
cgcccagtcc gctttctggt 1080 atgccgtgcg tatcgaagcc cgcctgcagg
cctcggtcga cgccgaatct agaagcgata 1140 aaattattca cctgactgac
gacagttttg acacggatgt actcaaagcg gacggggcga 1200 tcctcgtcga
tttctgggca gagtggtgcg gtccgtgcaa aatgatcgcc ccgattctgg 1260
atgaaatcgc tgacgaatat cagggcaaac tgaccgttgc aaaactgaac atcgatcaaa
1320 accctggcac tgcgccgaaa tatggcatcc gtggtatccc gactctgctg
ctgttcaaaa 1380 acggtgaagt ggcggcaacc aaagtgggtg cactgtctaa
aggtcagttg aaagagaacc 1440 tggcggatta taaagatgac gatgacaaat aataag
1476
* * * * *
References