U.S. patent application number 10/376449 was filed with the patent office on 2003-09-04 for msras as modifiers of the p53 pathway and methods of use.
Invention is credited to Belvin, Marcia, Francis-Lang, Helen, Friedman, Lori, Heuer, Timothy S., Plowman, Gregory D..
Application Number | 20030165966 10/376449 |
Document ID | / |
Family ID | 27789086 |
Filed Date | 2003-09-04 |
United States Patent
Application |
20030165966 |
Kind Code |
A1 |
Belvin, Marcia ; et
al. |
September 4, 2003 |
MSRAs as modifiers of the p53 pathway and methods of use
Abstract
Human MSRA genes are identified as modulators of the p53
pathway, and thus are therapeutic targets for disorders associated
with defective p53 function. Methods for identifying modulators of
p53, comprising screening for agents that modulate the activity of
MSRA are provided.
Inventors: |
Belvin, Marcia; (Albany,
CA) ; Francis-Lang, Helen; (San Francisco, CA)
; Friedman, Lori; (San Carlos, CA) ; Plowman,
Gregory D.; (San Carlos, CA) ; Heuer, Timothy S.;
(Pacifica, CA) |
Correspondence
Address: |
JAN P. BRUNELLE
EXELIXIS, INC.
170 HARBOR WAY
P.O. BOX 511
SOUTH SAN FRANCISCO
CA
94083-0511
US
|
Family ID: |
27789086 |
Appl. No.: |
10/376449 |
Filed: |
February 28, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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60361196 |
Mar 1, 2002 |
|
|
|
Current U.S.
Class: |
435/6.16 ;
435/26; 435/7.2 |
Current CPC
Class: |
G01N 2500/10 20130101;
G01N 33/57423 20130101; A61P 43/00 20180101; C12Q 1/485 20130101;
G01N 33/5017 20130101; G01N 33/57419 20130101; G01N 33/57484
20130101; G01N 2333/82 20130101; G01N 2500/00 20130101; G01N
2333/912 20130101; G01N 33/6872 20130101; C12Q 1/527 20130101; G01N
33/57496 20130101; G01N 33/57415 20130101; G01N 33/5748 20130101;
G01N 2333/988 20130101; G01N 33/57449 20130101; G01N 2510/00
20130101; G01N 33/573 20130101; G01N 33/574 20130101; G01N 33/5011
20130101; G01N 2333/90212 20130101 |
Class at
Publication: |
435/6 ; 435/7.2;
435/26 |
International
Class: |
C12Q 001/68; G01N
033/53; G01N 033/567; C12Q 001/32 |
Claims
What is claimed is:
1. A method of identifying a candidate p53 pathway modulating
agent, said method comprising the steps of: (a) providing an assay
system comprising a MSRA polypeptide or nucleic acid; (b)
contacting the assay system with a test agent under conditions
whereby, but for the presence of the test agent, the system
provides a reference activity; and (c) detecting a test
agent-biased activity of the assay system, wherein a difference
between the test agent-biased activity and the reference activity
identifies the test agent as a candidate p53 pathway modulating
agent.
2. The method of claim 1 wherein the assay system comprises
cultured cells that express the MSRA polypeptide.
3. The method of claim 2 wherein the cultured cells additionally
have defective p53 function.
4. The method of claim 1 wherein the assay system includes a
screening assay comprising a MSRA polypeptide, and the candidate
test agent is a small molecule modulator.
5. The method of claim 4 wherein the assay is a reductase
assay.
6. The method of claim 1 wherein the assay system is selected from
the group consisting of an apoptosis assay system, a cell
proliferation assay system, an angiogenesis assay system, and a
hypoxic induction assay system.
7. The method of claim 1 wherein the assay system includes a
binding assay comprising a MSRA polypeptide and the candidate test
agent is an antibody.
8. The method of claim 1 wherein the assay system includes an
expression assay comprising a MSRA nucleic acid and the candidate
test agent is a nucleic acid modulator.
9. The method of claim 8 wherein the nucleic acid modulator is an
antisense oligomer.
10. The method of claim 8 wherein the nucleic acid modulator is a
PMO.
11. The method of claim 1 additionally comprising: (d)
administering the candidate p53 pathway modulating agent identified
in (c) to a model system comprising cells defective in p53 function
and, detecting a phenotypic change in the model system that
indicates that the p53 function is restored.
12. The method of claim 11 wherein the model system is a mouse
model with defective p53 function.
13. A method for modulating a p53 pathway of a cell comprising
contacting a cell defective in p53 function with a candidate
modulator that specifically binds to a MSRA polypeptide comprising
an amino acid sequence as set forth in SEQ ID NO:4 whereby p53
function is restored.
14. The method of claim 13 wherein the candidate modulator is
administered to a vertebrate animal predetermined to have a disease
or disorder resulting from a defect in p53 function.
15. The method of claim 13 wherein the candidate modulator is
selected from the group consisting of an antibody and a small
molecule.
16. The method of claim 1, comprising the additional steps of: (e)
providing a secondary assay system comprising cultured cells or a
non-human animal expressing MSRA, (f) contacting the secondary
assay system with the test agent of (b) or an agent derived
therefrom under conditions whereby, but for the presence of the
test agent or agent derived therefrom, the system provides a
reference activity; and (g) detecting an agent-biased activity of
the second assay system, wherein a difference between the
agent-biased activity and the reference activity of the second
assay system confirms the test agent or agent derived therefrom as
a candidate p53 pathway modulating agent, and wherein the second
assay detects an agent-biased change in the p53 pathway.
17. The method of claim 16 wherein the secondary assay system
comprises cultured cells.
18. The method of claim 16 wherein the secondary assay system
comprises a non-human animal.
19. The method of claim 18 wherein the non-human animal
mis-expresses a p53 pathway gene.
20. A method of modulating p53 pathway in a mammalian cell
comprising contacting the cell with an agent that specifically
binds a MSRA polypeptide or nucleic acid.
21. The method of claim 20 wherein the agent is administered to a
mammalian animal predetermined to have a pathology associated with
the p53 pathway.
22. The method of claim 20 wherein the agent is a small molecule
modulator, a nucleic acid modulator, or an antibody.
23. A method for diagnosing a disease in a patient comprising: (a)
obtaining a biological sample from the patient; (b) contacting the
sample with a probe for MSRA expression; (c) comparing results from
step (b) with a control; (d) determining whether step (c) indicates
a likelihood of disease.
24. The method of claim 23 wherein said disease is cancer.
25. The method according to claim 24, wherein said cancer is skin
cancer.
Description
REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to U.S. provisional patent
application 60/361,196 filed Mar. 1, 2002. The contents of the
prior applications are hereby incorporated in their entirety.
BACKGROUND OF THE INVENTION
[0002] The p53 gene is mutated in over 50 different types of human
cancers, including familial and spontaneous cancers, and is
believed to be the most commonly mutated gene in human cancer
(Zambetti and Levine, FASEB (1993) 7:855-865; Hollstein, et al.,
Nucleic Acids Res. (1994) 22:3551-3555). Greater than 90% of
mutations in the p53 gene are missense mutations that alter a
single amino acid that inactivates p53 function. Aberrant forms of
human p53 are associated with poor prognosis, more aggressive
tumors, metastasis, and short survival rates (Mitsudomi et al.,
Clin Cancer Res October 2000; 6(10):4055-63; Koshland, Science
(1993) 262:1953).
[0003] The human p53 protein normally functions as a central
integrator of signals including DNA damage, hypoxia, nucleotide
deprivation, and oncogene activation (Prives, Cell (1998) 95:5-8).
In response to these signals, p53 protein levels are greatly
increased with the result that the accumulated p53 activates cell
cycle arrest or apoptosis depending on the nature and strength of
these signals. Indeed, multiple lines of experimental evidence have
pointed to a key role for p53 as a tumor suppressor (Levine, Cell
(1997) 88:323-331). For example, homozygous p53 "knockout" mice are
developmentally normal but exhibit nearly 100% incidence of
neoplasia in the first year of life (Donehower et al., Nature
(1992) 356:215-221).
[0004] The biochemical mechanisms and pathways through which p53
functions in normal and cancerous cells are not fully understood,
but one clearly important aspect of p53 function is its activity as
a gene-specific transcriptional activator. Among the genes with
known p53-response elements are several with well-characterized
roles in either regulation of the cell cycle or apoptosis,
including GADD45, p21/Waf1/Cip1, cyclin G, Bax, IGF-BP3, and MDM2
(Levine, Cell (1997) 88:323-331).
[0005] Oxidation of methionine residues in proteins is mediated by
various biologic oxidants such as H(2)O(2), hydroxyl radicals,
hypochlorite, and superoxide ions. The oxidized product, methionine
sulfoxide, can be enzymatically reduced back to methionine by
peptide methionine sulfoxide reductase (MSRA), which has been
detected in virtually all organisms and tissues examined. It is
suggested that MSRA functions to repair oxidative damage to
proteins that may occur during oxidative bursts or other situations
where reactive oxygen radicals exist. Oxidation of proteins by
reactive oxygen species is associated with aging, oxidative stress,
and many diseases. Although free and protein-bound methionine
residues are particularly sensitive to oxidation to methionine
sulfoxide derivatives, these oxidations are readily repaired by the
action of methionine sulfoxide reductase. Mice lacking the MSRA
gene have been produced. Compared with the wildtype, these mutants
exhibited enhanced sensitivity to oxidative stress (exposure to
100% oxygen); had a shorter life span under both normal and
hyperoxic conditions; developed an atypical (tip-toe) walking
pattern after 6 months of age; accumulated higher tissue levels of
oxidized protein (carbonyl derivatives) under oxidative stress; and
were less able to upregulate expression of thioredoxin reductase
under oxidative stress. Thus, methionine sulfoxide reductase may
play an important role in aging and neurologic disorders. Further,
MSRA may be important in increasing the lifespan in other
organisms, including humans (Moskovitz, J et al (2001) Proc. Nat.
Acad. Sci. 98: 12920-12925; Moskovitz, J. et al (1996) Proc. Nat.
Acad. Sci. 93: 3205-3208; Moskovitz, J. et al (1996) Proc. Nat.
Acad. Sci. 93: 2095-2099; Ruan, H. et al (2002) Proc. Nat. Acad.
Sci. 99: 2748-2753).
[0006] The ability to manipulate the genomes of model organisms
such as Drosophila provides a powerful means to analyze biochemical
processes that, due to significant evolutionary conservation, have
direct relevance to more complex vertebrate organisms. Due to a
high level-of gene and pathway conservation, the strong similarity
of cellular processes, and the functional conservation of genes
between these model organisms and mammals, identification of the
involvement of novel genes in particular pathways and their
functions in such model organisms can directly contribute to the
understanding of the correlative pathways and methods of modulating
them in mammals (see, for example, Mechler B M et al., 1985 EMBO J
4:1551-1557; Gateff E. 1982 Adv. Cancer Res. 37: 33-74; Watson K
L., et al., 1994 J Cell Sci. 18: 19-33; Miklos G L, and Rubin G M.
1996 Cell 86:521-529; Wassarman D A, et al., 1995 Curr Opin Gen Dev
5: 44-50; and Booth D R. 1999 Cancer Metastasis Rev. 18: 261-284).
For example, a genetic screen can be carried out in an invertebrate
model organism having underexpression (e.g. knockout) or
overexpression of a gene (referred to as a "genetic entry point")
that yields a visible phenotype. Additional genes are mutated in a
random or targeted manner. When a gene mutation changes the
original phenotype caused by the mutation in the genetic entry
point, the gene is identified as a "modifier" involved in the same
or overlapping pathway as the genetic entry point. When the genetic
entry point is an ortholog of a human gene implicated in a disease
pathway, such as p53, modifier genes can be identified that may be
attractive candidate targets for novel therapeutics.
[0007] All references cited herein, including patents, patent
applications, publications, and sequence information in referenced
Genbank identifier numbers, are incorporated herein in their
entireties.
SUMMARY OF THE INVENTION
[0008] We have discovered genes that modify the p53 pathway in
Drosophila, and identified their human orthologs, hereinafter
referred to as methionine sulfoxide reductase (MSRA). The invention
provides methods for utilizing these p53 modifier genes and
polypeptides to identify MSRA-modulating agents that are candidate
therapeutic agents that can be used in the treatment of disorders
associated with defective or impaired p53 function and/or MSRA
function. Preferred MSRA-modulating agents specifically bind to
MSRA polypeptides and restore p53 function. Other preferred
MSRA-modulating agents are nucleic acid modulators such as
antisense oligomers and RNAi that repress MSRA gene expression or
product activity by, for example, binding to and inhibiting the
respective nucleic acid (i.e. DNA or mRNA).
[0009] MSRA modulating agents may be evaluated by any convenient in
vitro or in vivo assay for molecular interaction with an MSRA
polypeptide or nucleic acid. In one embodiment, candidate MSRA
modulating agents are tested with an assay system comprising a MSRA
polypeptide or nucleic acid. Agents that produce a change in the
activity of the assay system relative to controls are identified as
candidate p53 modulating agents. The assay system may be cell-based
or cell-free. MSRA-modulating agents include MSRA related proteins
(e.g. dominant negative mutants, and biotherapeutics);
MSRA-specific antibodies; MSRA-specific antisense oligomers and
other nucleic acid modulators; and chemical agents that
specifically bind to or interact with MSRA or compete with MSRA
binding partner (e.g. by binding to an MSRA binding partner). In
one specific embodiment, a small molecule modulator is identified
using a reductase assay. In specific embodiments, the screening
assay system is selected from a binding assay, an apoptosis assay,
a cell proliferation assay, an angiogenesis assay, and a hypoxic
induction assay.
[0010] In another embodiment, candidate p53 pathway modulating
agents are further tested using a second assay system that detects
changes in the p53 pathway, such as angiogenic, apoptotic, or cell
proliferation changes produced by the originally identified
candidate agent or an agent derived from the original agent. The
second assay system may use cultured cells or non-human animals. In
specific embodiments, the secondary assay system uses non-human
animals, including animals predetermined to have a disease or
disorder implicating the p53 pathway, such as an angiogenic,
apoptotic, or cell proliferation disorder (e.g. cancer).
[0011] The invention further provides methods for modulating the
MSRA function and/or the p53 pathway in a mammalian cell by
contacting the mammalian cell with an agent that specifically binds
a MSRA polypeptide or nucleic acid. The agent may be a small
molecule modulator, a nucleic acid modulator, or an antibody and
may be administered to a mammalian animal predetermined to have a
pathology associated the p53 pathway.
DETAILED DESCRIPTION OF THE INVENTION
[0012] Genetic screens were designed to identify modifiers of the
p53 pathway in Drosophila, where a genetic modifier screen was
carried out in which p53 was overexpressed in the wing (Ollmann M,
et al., Cell 2000 101: 91-101). The CG7266 gene was identified as a
modifier of the p53 pathway. Accordingly, vertebrate orthologs of
these modifiers, and preferably the human orthologs, MSRA genes
(i.e., nucleic acids and polypeptides) are attractive drug targets
for the treatment of pathologies associated with a defective p53
signaling pathway, such as cancer.
[0013] In vitro and in vivo methods of assessing MSRA function are
provided herein. Modulation of the MSRA or their respective binding
partners is useful for understanding the association of the p53
pathway and its members in normal and disease conditions and for
developing diagnostics and therapeutic modalities for p53 related
pathologies. MSRA-modulating agents that act by inhibiting or
enhancing MSRA expression, directly or indirectly, for example, by
affecting an MSRA function such as enzymatic (e.g., catalytic) or
binding activity, can be identified using methods provided herein.
MSRA modulating agents are useful in diagnosis, therapy and
pharmaceutical development.
[0014] Nucleic Acids and Polypeptides of the Invention
[0015] Sequences related to MSRA nucleic acids and polypeptides
that can be used in the invention are disclosed in Genbank
(referenced by Genbank identifier (GI) number) as GI#s 13259538
(SEQ ID NO:1), 9963778 (SEQ ID NO:2), and 20542829 (SEQ ID NO:3)
for nucleic acid, and GI# 6912516 (SEQ ID NO:4) for
polypeptides.
[0016] The term "MSRA polypeptide" refers to a full-length MSRA
protein or a functionally active fragment or derivative thereof. A
"functionally active" MSRA fragment or derivative exhibits one or
more functional activities associated with a full-length, wild-type
MSRA protein, such as antigenic or immunogenic activity, enzymatic
activity, ability to bind natural cellular substrates, etc. The
functional activity of MSRA proteins, derivatives and fragments can
be assayed by various methods known to one skilled in the art
(Current Protocols in Protein Science (1998) Coligan et al., eds.,
John Wiley & Sons, Inc., Somerset, N.J.) and as further
discussed below. In one embodiment, a functionally active MSRA
polypeptide is a MSRA derivative capable of rescuing defective
endogenous MSRA activity, such as in cell based or animal assays;
the rescuing derivative may be from the same or a different
species. For purposes herein, functionally active fragments also
include those fragments that comprise one or more structural
domains of an MSRA, such as a binding domain. Protein domains can
be identified using the PFAM program (Bateman A., et al., Nucleic
Acids Res, 1999, 27:260-2). For example, the peptide methionine
sulfoxide reductase domain (PFAM 01625) of MSRA from GI# 6912516
(SEQ ID NO:4) is located at approximately amino acid residues 52 to
200. Methods for obtaining MSRA polypeptides are also further
described below. In some embodiments, preferred fragments are
functionally active, domain-containing fragments comprising at
least 25 contiguous amino acids, preferably at least 50, more
preferably 75, and most preferably at least 100 contiguous amino
acids of SEQ ID NO:4 (an MSRA). In further preferred embodiments,
the fragment comprises the functionally active domain.
[0017] The term "MSRA nucleic acid" refers to a DNA or RNA molecule
that encodes a MSRA polypeptide. Preferably, the MSRA polypeptide
or nucleic acid or fragment thereof is from a human, but can also
be an ortholog, or derivative thereof with at least 70% sequence
identity, preferably at least 80%, more preferably 85%, still more
preferably 90%, and most preferably at least 95% sequence identity
with human MSRA. Methods of identifying orthlogs are known in the
art. Normally, orthologs in different species retain the same
function, due to presence of one or more protein motifs and/or
3-dimensional structures. Orthologs are generally identified by
sequence homology analysis, such as BLAST analysis, usually using
protein bait sequences. Sequences are assigned as a potential
ortholog if the best hit sequence from the forward BLAST result
retrieves the original query sequence in the reverse BLAST (Huynen
M A and Bork P, Proc Natl Acad Sci (1998) 95:5849-5856; Huynen M A
et al., Genome Research (2000) 10:1204-1210). Programs for multiple
sequence alignment, such as CLUSTAL (Thompson J D et al, 1994,
Nucleic Acids Res 22:4673-4680) may be used to highlight conserved
regions and/or residues of orthologous proteins and to generate
phylogenetic trees. In a phylogenetic tree representing multiple
homologous sequences from diverse species (e.g., retrieved through
BLAST analysis), orthologous sequences from two species generally
appear closest on the tree with respect to all other sequences from
these two species. Structural threading or other analysis of
protein folding (e.g., using software by ProCeryon, Biosciences,
Salzburg, Austria) may also identify potential orthologs. In
evolution, when a gene duplication event follows speciation, a
single gene in one species, such as Drosophila, may correspond to
multiple genes (paralogs) in another, such as human. As used
herein, the term "orthologs" encompasses paralogs. As used herein,
"percent (%) sequence identity" with respect to a subject sequence,
or a specified portion of a subject sequence, is defined as the
percentage of nucleotides or amino acids in the candidate
derivative sequence identical with the nucleotides or amino acids
in the subject sequence (or specified portion thereof), after
aligning the sequences and introducing gaps, if necessary to
achieve the maximum percent sequence identity, as generated by the
program WU-BLAST-2.0a19 (Altschul et al., J. Mol. Biol. (1997)
215:403-410) with all the search parameters set to default values.
The HSP S and HSP S2 parameters are dynamic values and are
established by the program itself depending upon the composition of
the particular sequence and composition of the particular database
against which the sequence of interest is being searched. A %
identity value is determined by the number of matching identical
nucleotides or amino acids divided by the sequence length for which
the percent identity is being reported. "Percent (%) amino acid
sequence similarity" is determined by doing the same calculation as
for determining % amino acid sequence identity, but including
conservative amino acid substitutions in addition to identical
amino acids in the computation.
[0018] A conservative amino acid substitution is one in which an
amino acid is substituted for another amino acid having similar
properties such that the folding or activity of the protein is not
significantly affected. Aromatic amino acids that can be
substituted for each other are phenylalanine, tryptophan, and
tyrosine; interchangeable hydrophobic amino acids are leucine,
isoleucine, methionine, and valine; interchangeable polar amino
acids are glutamine and asparagine; interchangeable basic amino
acids are arginine, lysine and histidine; interchangeable acidic
amino acids are aspartic acid and glutamic acid; and
interchangeable small amino acids are alanine, serine, threonine,
cysteine and glycine.
[0019] Alternatively, an alignment for nucleic acid sequences is
provided by the local homology algorithm of Smith and Waterman
(Smith and Waterman, 1981, Advances in Applied Mathematics
2:482-489; database: European Bioinformatics Institute; Smith and
Waterman, 1981, J. of Molec. Biol., 147:195-197; Nicholas et al.,
1998, "A Tutorial on Searching Sequence Databases and Sequence
Scoring Methods" (www.psc.edu) and references cited therein.; W. R.
Pearson, 1991, Genomics 11:635-650). This algorithm can be applied
to amino acid sequences by using the scoring matrix developed by
Dayhoff (Dayhoff: Atlas of Protein Sequences and Structure, M. O.
Dayhoff ed., 5 suppl. 3:353-358, National Biomedical Research
Foundation, Washington, D.C., USA), and normalized by Gribskov
(Gribskov 1986 Nucl. Acids Res. 14(6):6745-6763). The
Smith-Waterman algorithm may be employed where default parameters
are used for scoring (for example, gap open penalty of 12, gap
extension penalty of two). From the data generated, the "Match"
value reflects "sequence identity."
[0020] Derivative nucleic acid molecules of the subject nucleic
acid molecules include sequences that hybridize to the nucleic acid
sequence of any of SEQ ID NOs:1-3. The stringency of hybridization
can be controlled by temperature, ionic strength, pH, and the
presence of denaturing agents such as formamide during
hybridization and washing. Conditions routinely used are set out in
readily available procedure texts (e.g., Current Protocol in
Molecular Biology, Vol. 1, Chap. 2.10, John Wiley & Sons,
Publishers (1994); Sambrook et al., Molecular Cloning, Cold Spring
Harbor (1989)). In some embodiments, a nucleic acid molecule of the
invention is capable of hybridizing to a nucleic acid molecule
containing the nucleotide sequence of any one of SEQ ID NOs:1-3
under high stringency hybridization conditions that are:
prehybridization of filters containing nucleic acid for 8 hours to
overnight at 65.degree. C. in a solution comprising 6.times. single
strength citrate (SSC) (1.times. SSC is 0.15 M NaCl, 0.015 M Na
citrate; pH 7.0), 5.times. Denhardt's solution, 0.05% sodium
pyrophosphate and 100 .mu.g/ml herring sperm DNA; hybridization for
18-20 hours at 65.degree. C. in a solution containing 6.times. SSC,
1.times. Denhardt's solution, 100 .mu.g/ml yeast tRNA and 0.05%
sodium pyrophosphate; and washing of filters at 65.degree. C. for 1
h in a solution containing 0.1.times. SSC and 0.1% SDS (sodium
dodecyl sulfate).
[0021] In other embodiments, moderately stringent hybridization
conditions are used that are: pretreatment of filters containing
nucleic acid for 6 h at 40.degree. C. in a solution containing 35%
formamide, 5.times. SSC, 50 mM Tris-HCl (pH 7.5), 5 mM EDTA, 0.1%
PVP, 0.1% Ficoll, 1% BSA, and 500 .mu.g/ml denatured salmon sperm
DNA; hybridization for 18-20 h at 40.degree. C. in a solution
containing 35% formamide, 5.times. SSC, 50 mM Tris-HCl (pH 7.5), 5
mM EDTA, 0.02% PVP, 0.02% Ficoll, 0.2% BSA, 100 .mu.g/ml salmon
sperm DNA, and 10% (wt/vol) dextran sulfate; followed by washing
twice for 1 hour at 55.degree. C. in a solution containing 2.times.
SSC and 0.1% SDS.
[0022] Alternatively, low stringency conditions can be used that
are: incubation for 8 hours to overnight at 37.degree. C. in a
solution comprising 20% formamide, 5.times. SSC, 50 mM sodium
phosphate (pH 7.6), 5.times. Denhardt's solution, 10% dextran
sulfate, and 20 .mu.g/ml denatured sheared salmon sperm DNA;
hybridization in the same buffer for 18 to 20 hours; and washing of
filters in 1.times. SSC at about 37.degree. C. for 1 hour.
[0023] Isolation, Production, Expression, and Mis-Expression of
MSRA Nucleic Acids and Polypeptides
[0024] MSRA nucleic acids and polypeptides, useful for identifying
and testing agents that modulate MSRA function and for other
applications related to the involvement of MSRA in the p53 pathway.
MSRA nucleic acids and derivatives and orthologs thereof may be
obtained using any available method. For instance, techniques for
isolating cDNA or genomic DNA sequences of interest by screening
DNA libraries or by using polymerase chain reaction (PCR) are well
known in the art. In general, the particular use for the protein
will dictate the particulars of expression, production, and
purification methods. For instance, production of proteins for use
in screening for modulating agents may require methods that
preserve specific biological activities of these proteins, whereas
production of proteins for antibody generation may require
structural integrity of particular epitopes. Expression of proteins
to be purified for screening or antibody production may require the
addition of specific tags (e.g., generation of fusion proteins).
Overexpression of an MSRA protein for assays used to assess MSRA
function, such as involvement in cell cycle regulation or hypoxic
response, may require expression in eukaryotic cell lines capable
of these cellular activities. Techniques for the expression,
production, and purification of proteins are well known in the art;
any suitable means therefore may be used (e.g., Higgins S J and
Hames B D (eds.) Protein Expression: A Practical Approach, Oxford
University Press Inc., New York 1999; Stanbury P F et al.,
Principles of Fermentation Technology, 2.sup.nd edition, Elsevier
Science, New York, 1995; Doonan S (ed.) Protein Purification
Protocols, Humana Press, New Jersey, 1996; Coligan J E et al,
Current Protocols in Protein Science (eds.), 1999, John Wiley &
Sons, New York). In particular embodiments, recombinant MSRA is
expressed in a cell line known to have defective p53 function (e.g.
SAOS-2 osteoblasts, H1299 lung cancer cells, C33A and HT3 cervical
cancer cells, HT-29 and DLD-1 colon cancer cells, among others,
available from American Type Culture Collection (ATCC), Manassas,
Va.). The recombinant cells are used in cell-based screening assay
systems of the invention, as described further below.
[0025] The nucleotide sequence encoding an MSRA polypeptide can be
inserted into any appropriate expression vector. The necessary
transcriptional and translational signals, including
promoter/enhancer element, can derive from the native MSRA gene
and/or its flanking regions or can be heterologous. A variety of
host-vector expression systems may be utilized, such as mammalian
cell systems infected with virus (e.g. vaccinia virus, adenovirus,
etc.); insect cell systems infected with virus (e.g. baculovirus);
microorganisms such as yeast containing yeast vectors, or bacteria
transformed with bacteriophage, plasmid, or cosmid DNA. An isolated
host cell strain that modulates the expression of, modifies, and/or
specifically processes the gene product may be used.
[0026] To detect expression of the MSRA gene product, the
expression vector can comprise a promoter operably linked to an
MSRA gene nucleic acid, one or more origins of replication, and,
one or more selectable markers (e.g. thymidine kinase activity,
resistance to antibiotics, etc.). Alternatively, recombinant
expression vectors can be identified by assaying for the expression
of the MSRA gene product based on the physical or functional
properties of the MSRA protein in in vitro assay systems (e.g.
immunoassays).
[0027] The MSRA protein, fragment, or derivative may be optionally
expressed as a fusion, or chimeric protein product (i.e. it is
joined via a peptide bond to a heterologous protein sequence of a
different protein), for example to facilitate purification or
detection. A chimeric product can be made by ligating the
appropriate nucleic acid sequences encoding the desired amino acid
sequences to each other using standard methods and expressing the
chimeric product. A chimeric product may also be made by protein
synthetic techniques, e.g. by use of a peptide synthesizer
(Hunkapiller et al., Nature (1984) 310:105-111).
[0028] Once a recombinant cell that expresses the MSRA gene
sequence is identified, the gene product can be isolated and
purified using standard methods (e.g. ion exchange, affinity, and
gel exclusion chromatography; centrifugation; differential
solubility; electrophoresis). Alternatively, native MSRA proteins
can be purified from natural sources, by standard methods (e.g.
immunoaffinity purification). Once a protein is obtained, it may be
quantified and its activity measured by appropriate methods, such
as immunoassay, bioassay, or other measurements of physical
properties, such as crystallography.
[0029] The methods of this invention may also use cells that have
been engineered for altered expression (mis-expression) of MSRA or
other genes associated with the p53 pathway. As used herein,
mis-expression encompasses ectopic expression, over-expression,
under-expression, and non-expression (e.g. by gene knock-out or
blocking expression that would otherwise normally occur).
[0030] Genetically Modified Animals
[0031] Animal models that have been genetically modified to alter
MSRA expression may be used in in vivo assays to test for activity
of a candidate p53 modulating agent, or to further assess the role
of MSRA in a p53 pathway process such as apoptosis or cell
proliferation. Preferably, the altered MSRA expression results in a
detectable phenotype, such as decreased or increased levels of cell
proliferation, angiogenesis, or apoptosis compared to control
animals having normal MSRA expression. The genetically modified
animal may additionally have altered p53 expression (e.g. p53
knockout). Preferred genetically modified animals are mammals such
as primates, rodents (preferably mice or rats), among others.
Preferred non-mammalian species include zebrafish, C. elegans, and
Drosophila. Preferred genetically modified animals are transgenic
animals having a heterologous nucleic acid sequence present as an
extrachromosomal element in a portion of its cells, i.e. mosaic
animals (see, for example, techniques described by Jakobovits,
1994, Curr. Biol. 4:761-763.) or stably integrated into its germ
line DNA (i.e., in the genomic sequence of most or all of its
cells). Heterologous nucleic acid is introduced into the germ line
of such transgenic animals by genetic manipulation of, for example,
embryos or embryonic stem cells of the host animal.
[0032] Methods of making transgenic animals are well-known in the
art (for transgenic mice see Brinster et al., Proc. Nat. Acad. Sci.
USA 82: 4438-4442 (1985), U.S. Pat. Nos. 4,736,866 and 4,870,009,
both by Leder et al., U.S. Pat. No. 4,873,191 by Wagner et al., and
Hogan, B., Manipulating the Mouse Embryo, Cold Spring Harbor
Laboratory Press, Cold Spring Harbor, N.Y., (1986); for particle
bombardment see U.S. Pat. No. 4,945,050, by Sandford et al.; for
transgenic Drosophila see Rubin and Spradling, Science (1982)
218:348-53 and U.S. Pat. No. 4,670,388; for transgenic insects see
Berghammer A. J. et al., A Universal Marker for Transgenic Insects
(1999) Nature 402:370-371; for transgenic Zebrafish see Lin S.,
Transgenic Zebrafish, Methods Mol Biol. (2000);136:375-3830); for
microinjection procedures for fish, amphibian eggs and birds see
Houdebine and Chourrout, Experientia (1991) 47:897-905; for
transgenic rats see Hammer et al., Cell (1990) 63:1099-1112; and
for culturing of embryonic stem (ES) cells and the subsequent
production of transgenic animals by the introduction of DNA into ES
cells using methods such as electroporation, calcium phosphate/DNA
precipitation and direct injection see, e.g., Teratocarcinomas and
Embryonic Stem Cells, A Practical Approach, E. J. Robertson, ed.,
IRL Press (1987)). Clones of the nonhuman transgenic animals can be
produced according to available methods (see Wilmut, I. et al.
(1997) Nature 385:810-813; and PCT International Publication Nos.
WO 97/07668 and WO 97/07669).
[0033] In one embodiment, the transgenic animal is a "knock-out"
animal having a heterozygous or homozygous alteration in the
sequence of an endogenous MSRA gene that results in a decrease of
MSRA function, preferably such that MSRA expression is undetectable
or insignificant. Knock-out animals are typically generated by
homologous recombination with a vector comprising a transgene
having at least a portion of the gene to be knocked out. Typically
a deletion, addition or substitution has been introduced into the
transgene to functionally disrupt it. The transgene can be a human
gene (e.g., from a human genomic clone) but more preferably is an
ortholog of the human gene derived from the transgenic host
species. For example, a mouse MSRA gene is used to construct a
homologous recombination vector suitable for altering an endogenous
MSRA gene in the mouse genome. Detailed methodologies for
homologous recombination in mice are available (see Capecchi,
Science (1989) 244:1288-1292; Joyner et al., Nature (1989)
338:153-156). Procedures for the production of non-rodent
transgenic mammals and other animals are also available (Houdebine
and Chourrout, supra; Pursel et al., Science (1989) 244:1281-1288;
Simms et al., Bio/Technology (1988) 6:179-183). In a preferred
embodiment, knock-out animals, such as mice harboring a knockout of
a specific gene, may be used to produce antibodies against the
human counterpart of the gene that has been knocked out (Claesson M
H et al., (1994) Scan J Immunol 40:257-264; Declerck P J et al.,
(1995) J Biol Chem. 270:8397-400).
[0034] In another embodiment, the transgenic animal is a "knock-in"
animal having an alteration in its genome that results in altered
expression (e.g., increased (including ectopic) or decreased
expression) of the MSRA gene, e.g., by introduction of additional
copies of MSRA, or by operatively inserting a regulatory sequence
that provides for altered expression of an endogenous copy of the
MSRA gene. Such regulatory sequences include inducible,
tissue-specific, and constitutive promoters and enhancer elements.
The knock-in can be homozygous or heterozygous.
[0035] Transgenic nonhuman animals can also be produced that
contain selected systems allowing for regulated expression of the
transgene. One example of such a system that may be produced is the
cre/loxP recombinase system of bacteriophage P1 (Lakso et al., PNAS
(1992) 89:6232-6236; U.S. Pat. No. 4,959,317). If a cre/loxP
recombinase system is used to regulate expression of the transgene,
animals containing transgenes encoding both the Cre recombinase and
a selected protein are required. Such animals can be provided
through the construction of "double" transgenic animals, e.g., by
mating two transgenic animals, one containing a transgene encoding
a selected protein and the other containing a transgene encoding a
recombinase. Another example of a recombinase system is the FLP
recombinase system of Saccharomyces cerevisiae (O'Gorman et al.
(1991) Science 251:1351-1355; U.S. Pat. No. 5,654,182). In a
preferred embodiment, both Cre-LoxP and Flp-Frt are used in the
same system to regulate expression of the transgene, and for
sequential deletion of vector sequences in the same cell (Sun X et
al (2000) Nat Genet 25:83-6).
[0036] The genetically modified animals can be used in genetic
studies to further elucidate the p53 pathway, as animal models of
disease and disorders implicating defective p53 function, and for
in vivo testing of candidate therapeutic agents, such as those
identified in screens described below. The candidate therapeutic
agents are administered to a genetically modified animal having
altered MSRA function and phenotypic changes are compared with
appropriate control animals such as genetically modified animals
that receive placebo treatment, and/or animals with unaltered MSRA
expression that receive candidate therapeutic agent.
[0037] In addition to the above-described genetically modified
animals having altered MSRA function, animal models having
defective p53 function (and otherwise normal MSRA function), can be
used in the methods of the present invention. For example, a p53
knockout mouse can be used to assess, in vivo, the activity of a
candidate p53 modulating agent identified in one of the in vitro
assays described below. p53 knockout mice are described in the
literature (Jacks et al., Nature 2001;410:1111-1116, 1043-1044;
Donehower et al., supra). Preferably, the candidate p53 modulating
agent when administered to a model system with cells defective in
p53 function, produces a detectable phenotypic change in the model
system indicating that the p53 function is restored, i.e., the
cells exhibit normal cell cycle progression.
[0038] Modulating Agents
[0039] The invention provides methods to identify agents that
interact with and/or modulate the function of MSRA and/or the p53
pathway. Modulating agents identified by the methods are also part
of the invention. Such agents are useful in a variety of diagnostic
and therapeutic applications associated with the p53 pathway, as
well as in further analysis of the MSRA protein and its
contribution to the p53 pathway. Accordingly, the invention also
provides methods for modulating the p53 pathway comprising the step
of specifically modulating MSRA activity by administering a
MSRA-interacting or -modulating agent.
[0040] As used herein, an "MSRA-modulating agent" is any agent that
modulates MSRA function, for example, an agent that interacts with
MSRA to inhibit or enhance MSRA activity or otherwise affect normal
MSRA function. MSRA function can be affected at any level,
including transcription, protein expression, protein localization,
and cellular or extra-cellular activity. In a preferred embodiment,
the MSRA-modulating agent specifically modulates the function of
the MSRA. The phrases "specific modulating agent", "specifically
modulates", etc., are used herein to refer to modulating agents
that directly bind to the MSRA polypeptide or nucleic acid, and
preferably inhibit, enhance, or otherwise alter, the function of
the MSRA. These phrases also encompass modulating agents that alter
the interaction of the MSRA with a binding partner, substrate, or
cofactor (e.g. by binding to a binding partner of an MSRA, or to a
protein/binding partner complex, and altering MSRA function). In a
further preferred embodiment, the MSRA-modulating agent is a
modulator of the p53 pathway (e.g. it restores and/or upregulates
p53 function) and thus is also a p53-modulating agent.
[0041] Preferred MSRA-modulating agents include small molecule
compounds; MSRA-interacting proteins, including antibodies and
other biotherapeutics; and nucleic acid modulators such as
antisense and RNA inhibitors. The modulating agents may be
formulated in pharmaceutical compositions, for example, as
compositions that may comprise other active ingredients, as in
combination therapy, and/or suitable carriers or excipients.
Techniques for formulation and administration of the compounds may
be found in "Remington's Pharmaceutical Sciences" Mack Publishing
Co., Easton, Pa., 19.sup.th edition.
[0042] Small Molecule Modulators
[0043] Small molecules are often preferred to modulate function of
proteins with enzymatic function, and/or containing protein
interaction domains. Chemical agents, referred to in the art as
"small molecule" compounds are typically organic, non-peptide
molecules, having a molecular weight less than 10,000, preferably
less than 5,000, more preferably less than 1,000, and most
preferably less than 500. This class of modulators includes
chemically synthesized molecules, for instance, compounds from
combinatorial chemical libraries. Synthetic compounds may be
rationally designed or identified based on known or inferred
properties of the MSRA protein or may be identified by screening
compound libraries. Alternative appropriate modulators of this
class are natural products, particularly secondary metabolites from
organisms such as plants or fungi, which can also be identified by
screening compound libraries for MSRA-modulating activity. Methods
for generating and obtaining compounds are well known in the art
(Schreiber S L, Science (2000) 151: 1964-1969; Radmann J and
Gunther J, Science (2000) 151:1947-1948).
[0044] Small molecule modulators identified from screening assays,
as described below, can be used as lead compounds from which
candidate clinical compounds may be designed, optimized, and
synthesized. Such clinical compounds may have utility in treating
pathologies associated with the p53 pathway. The activity of
candidate small molecule modulating agents may be improved
several-fold through iterative secondary functional validation, as
further described below, structure determination, and candidate
modulator modification and testing. Additionally, candidate
clinical compounds are generated with specific regard to clinical
and pharmacological properties. For example, the reagents may be
derivatized and re-screened using in vitro and in vivo assays to
optimize activity and minimize toxicity for pharmaceutical
development.
[0045] Protein Modulators
[0046] Specific MSRA-interacting proteins are useful in a variety
of diagnostic and therapeutic applications related to the p53
pathway and related disorders, as well as in validation assays for
other MSRA-modulating agents. In a preferred embodiment,
MSRA-interacting proteins affect normal MSRA function, including
transcription, protein expression, protein localization, and
cellular or extra-cellular activity. In another embodiment,
MSRA-interacting proteins are useful in detecting and providing
information about the function of MSRA proteins, as is relevant to
p53 related disorders, such as cancer (e.g., for diagnostic
means).
[0047] An MSRA-interacting protein may be endogenous, i.e. one that
naturally interacts genetically or biochemically with an MSRA, such
as a member of the MSRA pathway that modulates MSRA expression,
localization, and/or activity. MSRA-modulators include dominant
negative forms of MSRA-interacting proteins and of MSRA proteins
themselves. Yeast two-hybrid and variant screens offer preferred
methods for identifying endogenous MSRA-interacting proteins
(Finley, R. L. et al. (1996) in DNA Cloning-Expression Systems: A
Practical Approach, eds. Glover D. & Hames B. D (Oxford
University Press, Oxford, England), pp. 169-203; Fashema S F et
al., Gene (2000) 250:1-14; Drees B L Curr Opin Chem Biol (1999)
3:64-70; Vidal M and Legrain P Nucleic Acids Res (1999) 27:919-29;
and U.S. Pat. No. 5,928,868). Mass spectrometry is an alternative
preferred method for the elucidation of protein complexes (reviewed
in, e.g., Pandley A and Mann M, Nature (2000) 405:837-846; Yates J
R 3.sup.rd, Trends Genet (2000) 16:5-8).
[0048] An MSRA-interacting protein may be an exogenous protein,
such as an MSRA-specific antibody or a T-cell antigen receptor
(see, e.g., Harlow and Lane (1988) Antibodies, A Laboratory Manual,
Cold Spring Harbor Laboratory; Harlow and Lane (1999) Using
antibodies: a laboratory manual. Cold Spring Harbor, N.Y.: Cold
Spring Harbor Laboratory Press). MSRA antibodies are further
discussed below.
[0049] In preferred embodiments, an MSRA-interacting protein
specifically binds an MSRA protein. In alternative preferred
embodiments, an MSRA-modulating agent binds an MSRA substrate,
binding partner, or cofactor.
[0050] Antibodies
[0051] In another embodiment, the protein modulator is an MSRA
specific antibody agonist or antagonist. The antibodies have
therapeutic and diagnostic utilities, and can be used in screening
assays to identify MSRA modulators. The antibodies can also be used
in dissecting the portions of the MSRA pathway responsible for
various cellular responses and in the general processing and
maturation of the MSRA.
[0052] Antibodies that specifically bind MSRA polypeptides can be
generated using known methods. Preferably the antibody is specific
to a mammalian ortholog of MSRA polypeptide, and more preferably,
to human MSRA. Antibodies may be polyclonal, monoclonal (mAbs),
humanized or chimeric antibodies, single chain antibodies, Fab
fragments, F(ab').sub.2 fragments, fragments produced by a FAb
expression library, anti-idiotypic (anti-Id) antibodies, and
epitope-binding fragments of any of the above. Epitopes of MSRA
which are particularly antigenic can be selected, for example, by
routine screening of MSRA polypeptides for antigenicity or by
applying a theoretical method for selecting antigenic regions of a
protein (Hopp and Wood (1981), Proc. Nati. Acad. Sci. U.S.A.
78:3824-28; Hopp and Wood, (1983) Mol. Immunol. 20:483-89;
Sutcliffe et al., (1983) Science 219:660-66) to the amino acid
sequence shown in SEQ ID NO:4. Monoclonal antibodies with
affinities of 10.sup.8 M.sup.-1 preferably 10.sup.9 M.sup.-1 to
10.sup.10 M.sup.-1, or stronger can be made by standard procedures
as described (Harlow and Lane, supra; Goding (1986) Monoclonal
Antibodies: Principles and Practice (2d ed) Academic Press, New
York; and U.S. Pat. Nos. 4,381,292; 4,451,570; and 4,618,577).
Antibodies may be generated against crude cell extracts of MSRA or
substantially purified fragments thereof. If MSRA fragments are
used, they preferably comprise at least 10, and more preferably, at
least 20 contiguous amino acids of an MSRA protein. In a particular
embodiment, MSRA-specific antigens and/or immunogens are coupled to
carrier proteins that stimulate the immune response. For example,
the subject polypeptides are covalently coupled to the keyhole
limpet hemocyanin (KLH) carrier, and the conjugate is emulsified in
Freund's complete adjuvant, which enhances the immune response. An
appropriate immune system such as a laboratory rabbit or mouse is
immunized according to conventional protocols.
[0053] The presence of MSRA-specific antibodies is assayed by an
appropriate assay such as a solid phase enzyme-linked immunosorbant
assay (ELISA) using immobilized corresponding MSRA polypeptides.
Other assays, such as radioimmunoassays or fluorescent assays might
also be used.
[0054] Chimeric antibodies specific to MSRA polypeptides can be
made that contain different portions from different animal species.
For instance, a human immunoglobulin constant region may be linked
to a variable region of a murine mAb, such that the antibody
derives its biological activity from the human antibody, and its
binding specificity from the murine fragment. Chimeric antibodies
are produced by splicing together genes that encode the appropriate
regions from each species (Morrison et al., Proc. Natl. Acad. Sci.
(1984) 81:6851-6855; Neuberger et al., Nature (1984) 312:604-608;
Takeda et al., Nature (1985) 31:452-454). Humanized antibodies,
which are a form of chimeric antibodies, can be generated by
grafting complementary-determining regions (CDRs) (Carlos, T. M.,
J. M. Harlan. 1994. Blood 84:2068-2101) of mouse antibodies into a
background of human framework regions and constant regions by
recombinant DNA technology (Riechmann L M, et al., 1988 Nature 323:
323-327). Humanized antibodies contain .about.10% murine sequences
and .about.90% human sequences, and thus further reduce or
eliminate immunogenicity, while retaining the antibody
specificities (Co M S, and Queen C. 1991 Nature 351: 501-501;
Morrison S L. 1992 Ann. Rev. Immun. 10:239-265). Humanized
antibodies and methods of their production are well-known in the
art (U.S. Pat. Nos. 5,530,101, 5,585,089, 5,693,762, and
6,180,370).
[0055] MSRA-specific single chain antibodies which are recombinant,
single chain polypeptides formed by linking the heavy and light
chain fragments of the Fv regions via an amino acid bridge, can be
produced by methods known in the art (U.S. Pat. No. 4,946,778;
Bird, Science (1988) 242:423-426; Huston et al., Proc. Natl. Acad.
Sci. USA (1988) 85:5879-5883; and Ward et al., Nature (1989)
334:544-546).
[0056] Other suitable techniques for antibody production involve in
vitro exposure of lymphocytes to the antigenic polypeptides or
alternatively to selection of libraries of antibodies in phage or
similar vectors (Huse et al., Science (1989) 246:1275-1281). As
used herein, T-cell antigen receptors are included within the scope
of antibody modulators (Harlow and Lane, 1988, supra).
[0057] The polypeptides and antibodies of the present invention may
be used with or without modification. Frequently, antibodies will
be labeled by joining, either covalently or non-covalently, a
substance that provides for a detectable signal, or that is toxic
to cells that express the targeted protein (Menard S, et al., Int
J. Biol Markers (1989) 4:131-134). A wide variety of labels and
conjugation techniques are known and are reported extensively in
both the scientific and patent literature. Suitable labels include
radionuclides, enzymes, substrates, cofactors, inhibitors,
fluorescent moieties, fluorescent emitting lanthanide metals,
chemiluminescent moieties, bioluminescent moieties, magnetic
particles, and the like (U.S. Pat. Nos. 3,817,837; 3,850,752;
3,939,350; 3,996,345; 4,277,437; 4,275,149; and 4,366,241). Also,
recombinant immunoglobulins may be produced (U.S. Pat. No.
4,816,567). Antibodies to cytoplasmic polypeptides may be delivered
and reach their targets by conjugation with membrane-penetrating
toxin proteins (U.S. Pat. No. 6,086,900).
[0058] When used therapeutically in a patient, the antibodies of
the subject invention are typically administered parenterally, when
possible at the target site, or intravenously. The therapeutically
effective dose and dosage regimen is determined by clinical
studies. Typically, the amount of antibody administered is in the
range of about 0.1 mg/kg to about 10 mg/kg of patient weight. For
parenteral administration, the antibodies are formulated in a unit
dosage injectable form (e.g., solution, suspension, emulsion) in
association with a pharmaceutically acceptable vehicle. Such
vehicles are inherently nontoxic and non-therapeutic. Examples are
water, saline, Ringer's solution, dextrose solution, and 5% human
serum albumin. Nonaqueous vehicles such as fixed oils, ethyl
oleate, or liposome carriers may also be used. The vehicle may
contain minor amounts of additives, such as buffers and
preservatives, which enhance isotonicity and chemical stability or
otherwise enhance therapeutic potential. The antibodies'
concentrations in such vehicles are typically in the range of about
1 mg/ml to about 10 mg/ml. Immunotherapeutic methods are further
described in the literature (U.S. Pat. No. 5,859,206;
WO0073469).
[0059] Nucleic Acid Modulators
[0060] Other preferred MSRA-modulating agents comprise nucleic acid
molecules, such as antisense oligomers or double stranded RNA
(dsRNA), which generally inhibit MSRA activity. Preferred nucleic
acid modulators interfere with the function of the MSRA nucleic
acid such as DNA replication, transcription, translocation of the
MSRA RNA to the site of protein translation, translation of protein
from the MSRA RNA, splicing of the MSRA RNA to yield one or more
mRNA species, or catalytic activity which may be engaged in or
facilitated by the MSRA RNA.
[0061] In one embodiment, the antisense oligomer is an
oligonucleotide that is sufficiently complementary to an MSRA mRNA
to bind to and prevent translation, preferably by binding to the 5'
untranslated region. MSRA-specific antisense oligonucleotides,
preferably range from at least 6 to about 200 nucleotides. In some
embodiments the oligonucleotide is preferably at least 10, 15, or
20 nucleotides in length. In other embodiments, the oligonucleotide
is preferably less than 50, 40, or 30 nucleotides in length. The
oligonucleotide can be DNA or RNA or a chimeric mixture or
derivatives or modified versions thereof, single-stranded or
double-stranded. The oligonucleotide can be modified at the base
moiety, sugar moiety, or phosphate backbone. The oligonucleotide
may include other appending groups such as peptides, agents that
facilitate transport across the cell membrane,
hybridization-triggered cleavage agents, and intercalating
agents.
[0062] In another embodiment, the antisense oligomer is a
phosphothioate morpholino oligomer (PMO). PMOs are assembled from
four different morpholino subunits, each of which contain one of
four genetic bases (A, C, G, or T) linked to a six-membered
morpholine ring. Polymers of these subunits are joined by non-ionic
phosphodiamidate intersubunit linkages. Details of how to make and
use PMOs and other antisense oligomers are well known in the art
(e.g. see WO99/18193; Probst J C, Antisense Oligodeoxynucleotide
and Ribozyme Design, Methods. (2000) 22(3):271-281; Summerton J,
and Weller D. 1997 Antisense Nucleic Acid Drug Dev.:7:187-95; U.S.
Pat. No. 5,235,033; and U.S. Pat. No. 5,378,841).
[0063] Alternative preferred MSRA nucleic acid modulators are
double-stranded RNA species mediating RNA interference (RNAi). RNAi
is the process of sequence-specific, post-transcriptional gene
silencing in animals and plants, initiated by double-stranded RNA
(dsRNA) that is homologous in sequence to the silenced gene.
Methods relating to the use of RNAi to silence genes in C. elegans,
Drosophila, plants, and humans are known in the art (Fire A, et
al., 1998 Nature 391:806-811; Fire, A. Trends Genet. 15, 358-363
(1999); Sharp, P. A. RNA interference 2001. Genes Dev. 15, 485-490
(2001); Hammond, S. M., et al., Nature Rev. Genet. 2, 110-1119
(2001); Tuschl, T. Chem. Biochem. 2, 239-245 (2001); Hamilton, A.
et al., Science 286, 950-952 (1999); Hammond, S. M., et al., Nature
404, 293-296 (2000); Zamore, P. D., et al., Cell 101, 25-33 (2000);
Bernstein, E., et al., Nature 409, 363-366 (2001); Elbashir, S. M.,
et al., Genes Dev. 15, 188-200 (2001); WO0129058; WO9932619;
Elbashir S M, et al., 2001 Nature 411:494-498).
[0064] Nucleic acid modulators are commonly used as research
reagents, diagnostics, and therapeutics. For example, antisense
oligonucleotides, which are able to inhibit gene expression with
exquisite specificity, are often used to elucidate the function of
particular genes (see, for example, U.S. Pat. No. 6,165,790).
Nucleic acid modulators are also used, for example, to distinguish
between functions of various members of a biological pathway. For
example, antisense oligomers have been employed as therapeutic
moieties in the treatment of disease states in animals and man and
have been demonstrated in numerous clinical trials to be safe and
effective (Milligan J F, et al, Current Concepts in Antisense Drug
Design, J Med Chem. (1993) 36:1923-1937; Tonkinson J L et al.,
Antisense Oligodeoxynucleotides as Clinical Therapeutic Agents,
Cancer Invest. (1996) 14:54-65). Accordingly, in one aspect of the
invention, an MSRA-specific nucleic acid modulator is used in an
assay to further elucidate the role of the MSRA in the p53 pathway,
and/or its relationship to other members of the pathway. In another
aspect of the invention, an MSRA-specific antisense oligomer is
used as a therapeutic agent for treatment of p53-related disease
states.
[0065] Assay Systems
[0066] The invention provides assay systems and screening methods
for identifying specific modulators of MSRA activity. As used
herein, an "assay system" encompasses all the components required
for performing and analyzing results of an assay that detects
and/or measures a particular event. In general, primary assays are
used to identify or confirm a modulator's specific biochemical or
molecular effect with respect to the MSRA nucleic acid or protein.
In general, secondary assays further assess the activity of a MSRA
modulating agent identified by a primary assay and may confirm that
the modulating agent affects MSRA in a manner relevant to the p53
pathway. In some cases, MSRA modulators will be directly tested in
a secondary assay.
[0067] In a preferred embodiment, the screening method comprises
contacting a suitable assay system comprising an MSRA polypeptide
or nucleic acid with a candidate agent under conditions whereby,
but for the presence of the agent, the system provides a reference
activity (e.g. reductase activity), which is based on the
particular molecular event the screening method detects. A
statistically significant difference between the agent-biased
activity and the reference activity indicates that the candidate
agent modulates MSRA activity, and hence the p53 pathway. The MSRA
polypeptide or nucleic acid used in the assay may comprise any of
the nucleic acids or polypeptides described above.
[0068] Primary Assays
[0069] The type of modulator tested generally determines the type
of primary assay.
[0070] Primary Assays for Small Molecule Modulators
[0071] For small molecule modulators, screening assays are used to
identify candidate modulators. Screening assays may be cell-based
or may use a cell-free system that recreates or retains the
relevant biochemical reaction of the target protein (reviewed in
Sittampalam G S et al., Curr Opin Chem Biol (1997) 1:384-91 and
accompanying references). As used herein the term "cell-based"
refers to assays using live cells, dead cells, or a particular
cellular fraction, such as a membrane, endoplasmic reticulum, or
mitochondrial fraction. The term "cell free" encompasses assays
using substantially purified protein (either endogenous or
recombinantly produced), partially purified or crude cellular
extracts. Screening assays may detect a variety of molecular
events, including protein-DNA interactions, protein-protein
interactions (e.g., receptor-ligand binding), transcriptional
activity (e.g., using a reporter gene), enzymatic activity (e.g.,
via a property of the substrate), activity of second messengers,
immunogenicty and changes in cellular morphology or other cellular
characteristics. Appropriate screening assays may use a wide range
of detection methods including fluorescent, radioactive,
colorimetric, spectrophotometric, and amperometric methods, to
provide a read-out for the particular molecular event detected.
[0072] Cell-based screening assays usually require systems for
recombinant expression of MSRA and any auxiliary proteins demanded
by the particular assay. Appropriate methods for generating
recombinant proteins produce sufficient quantities of proteins that
retain their relevant biological activities and are of sufficient
purity to optimize activity and assure assay reproducibility. Yeast
two-hybrid and variant screens, and mass spectrometry provide
preferred methods for determining protein-protein interactions and
elucidation of protein complexes. In certain applications, when
MSRA-interacting proteins are used in screens to identify small
molecule modulators, the binding specificity of the interacting
protein to the MSRA protein may be assayed by various known methods
such as substrate processing (e.g. ability of the candidate
MSRA-specific binding agents to function as negative effectors in
MSRA-expressing cells), binding equilibrium constants (usually at
least about 10.sup.7 M.sup.-1, preferably at least about 10.sup.8
M.sup.-1, more preferably at least about 10.sup.9 M.sup.-1), and
immunogenicity (e.g. ability to elicit MSRA specific antibody in a
heterologous host such as a mouse, rat, goat or rabbit). For
enzymes and receptors, binding may be assayed by, respectively,
substrate and ligand processing.
[0073] The screening assay may measure a candidate agent's ability
to specifically bind to or modulate activity of a MSRA polypeptide,
a fusion protein thereof, or to cells or membranes bearing the
polypeptide or fusion protein. The MSRA polypeptide can be full
length or a fragment thereof that retains functional MSRA activity.
The MSRA polypeptide may be fused to another polypeptide, such as a
peptide tag for detection or anchoring, or to another tag. The MSRA
polypeptide is preferably human MSRA, or is an ortholog or
derivative thereof as described above. In a preferred embodiment,
the screening assay detects candidate agent-based modulation of
MSRA interaction with a binding target, such as an endogenous or
exogenous protein or other substrate that has MSRA-specific binding
activity, and can be used to assess normal MSRA gene function.
[0074] Suitable assay formats that may be adapted to screen for
MSRA modulators are known in the art. Preferred screening assays
are high throughput or ultra high throughput and thus provide
automated, cost-effective means of screening compound libraries for
lead compounds (Fernandes P B, Curr Opin Chem Biol (1998)
2:597-603; Sundberg S A, Curr Opin Biotechnol 2000, 11:47-53). In
one preferred embodiment, screening assays uses fluorescence
technologies, including fluorescence polarization, time-resolved
fluorescence, and fluorescence resonance energy transfer. These
systems offer means to monitor protein-protein or DNA-protein
interactions in which the intensity of the signal emitted from
dye-labeled molecules depends upon their interactions with partner
molecules (e.g., Selvin P R, Nat Struct Biol (2000) 7:730-4;
Fernandes P B, supra; Hertzberg R P and Pope A J, Curr Opin Chem
Biol (2000) 4:445-451).
[0075] A variety of suitable assay systems may be used to identify
candidate MSRA and p53 pathway modulators (e.g. U.S. Pat. Nos.
5,550,019 and 6,133,437 (apoptosis assays); U.S. Pat. No. 6,020,135
(p53 modulation), and U.S. Pat. Nos. 5,976,782, 6,225,118 and
6,444,434 (angiogenesis assays), among others). Specific preferred
assays are described in more detail below.
[0076] Reductases are enzymes of oxidoreductase class that catalyze
reactions in which metabolites are reduced. High throughput
screening assays for reductases may involve scintillation
(Fernandes P B. (1998) Curr Opin Chem Biol 2:597-603; Delaporte E
et al. (2001) J Biomol Screen 6:225-231).
[0077] Apoptosis assays. Assays for apoptosis may be performed by
terminal deoxynucleotidyl transferase-mediated digoxigenin-11-dUTP
nick end labeling (TUNEL) assay. The TUNEL assay is used to measure
nuclear DNA fragmentation characteristic of apoptosis (Lazebnik et
al., 1994, Nature 371, 346), by following the incorporation of
fluorescein-dUTP (Yonehara et al., 1989, J. Exp. Med. 169, 1747).
Apoptosis may further be assayed by acridine orange staining of
tissue culture cells (Lucas, R., et al., 1998, Blood 15:4730-41).
An apoptosis assay system may comprise a cell that expresses an
MSRA, and that optionally has defective p53 function (e.g. p53 is
over-expressed or under-expressed relative to wild-type cells). A
test agent can be added to the apoptosis assay system and changes
in induction of apoptosis relative to controls where no test agent
is added, identify candidate p53 modulating agents. In some
embodiments of the invention, an apoptosis assay may be used as a
secondary assay to test a candidate p53 modulating agents that is
initially identified using a cell-free assay system. An apoptosis
assay may also be used to test whether MSRA function plays a direct
role in apoptosis. For example, an apoptosis assay may be performed
on cells that over- or under-express MSRA relative to wild type
cells. Differences in apoptotic response compared to wild type
cells suggests that the MSRA plays a direct role in the apoptotic
response. Apoptosis assays are described further in U.S. Pat. No.
6,133,437.
[0078] Cell proliferation and cell cycle assays. Cell proliferation
may be assayed via bromodeoxyuridine (BRDU) incorporation. This
assay identifies a cell population undergoing DNA synthesis by
incorporation of BRDU into newly-synthesized DNA. Newly-synthesized
DNA may then be detected using an anti-BRDU antibody (Hoshino et
al., 1986, Int. J. Cancer 38, 369; Campana et al., 1988, J.
Immunol. Meth. 107, 79), or by other means.
[0079] Cell proliferation is also assayed via phospho-histone H3
staining, which identifies a cell population undergoing mitosis by
phosphorylation of histone H3. Phosphorylation of histone H3 at
serine 10 is detected using an antibody specfic to the
phosphorylated form of the serine 10 residue of histone H3.
(Chadlee, D. N. 1995, J. Biol. Chem 270:20098-105). Cell
Proliferation may also be examined using [.sup.3H]-thymidine
incorporation (Chen, J., 1996, Oncogene 13:1395-403; Jeoung, J.,
1995, J. Biol. Chem. 270:18367-73). This assay allows for
quantitative characterization of S-phase DNA syntheses. In this
assay, cells synthesizing DNA will incorporate [.sup.3H]-thymidine
into newly synthesized DNA. Incorporation can then be measured by
standard techniques such as by counting of radioisotope in a
scintillation counter (e.g., Beckman L S 3800 Liquid Scintillation
Counter). Another proliferation assay uses the dye Alamar Blue
(available from Biosource International), which fluoresces when
reduced in living cells and provides an indirect measurement of
cell number (Voytik-Harbin S L et al., 1998, In Vitro Cell Dev Biol
Anim 34:239-46).
[0080] Cell proliferation may also be assayed by colony formation
in soft agar (Sambrook et al., Molecular Cloning, Cold Spring
Harbor (1989)). For example, cells transformed with MSRA are seeded
in soft agar plates, and colonies are measured and counted after
two weeks incubation.
[0081] Involvement of a gene in the cell cycle may be assayed by
flow cytometry (Gray J W et al. (1986) Int J Radiat Biol Relat Stud
Phys Chem Med 49:237-55). Cells transfected with an MSRA may be
stained with propidium iodide and evaluated in a flow cytometer
(available from Becton Dickinson), which indicates accumulation of
cells in different stages of the cell cycle.
[0082] Accordingly, a cell proliferation or cell cycle assay system
may comprise a cell that expresses an MSRA, and that optionally has
defective p53 function (e.g. p53 is over-expressed or
under-expressed relative to wild-type cells). A test agent can be
added to the assay system and changes in cell proliferation or cell
cycle relative to controls where no test agent is added, identify
candidate p53 modulating agents. In some embodiments of the
invention, the cell proliferation or cell cycle assay may be used
as a secondary assay to test a candidate p53 modulating agents that
is initially identified using another assay system such as a
cell-free assay system. A cell proliferation assay may also be used
to test whether MSRA function plays a direct role in cell
proliferation or cell cycle. For example, a cell proliferation or
cell cycle assay may be performed on cells that over- or
under-express MSRA relative to wild type cells. Differences in
proliferation or cell cycle compared to wild type cells suggests
that the MSRA plays a direct role in cell proliferation or cell
cycle.
[0083] Angiogenesis. Angiogenesis may be assayed using various
human endothelial cell systems, such as umbilical vein, coronary
artery, or dermal cells. Suitable assays include Alamar Blue based
assays (available from Biosource International) to measure
proliferation; migration assays using fluorescent molecules, such
as the use of Becton Dickinson Falcon HTS FluoroBlock cell culture
inserts to measure migration of cells through membranes in presence
or absence of angiogenesis enhancer or suppressors; and tubule
formation assays based on the formation of tubular structures by
endothelial cells on Matrigel.RTM. (Becton Dickinson). Accordingly,
an angiogenesis assay system may comprise a cell that expresses an
MSRA, and that optionally has defective p53 function (e.g. p53 is
over-expressed or under-expressed relative to wild-type cells). A
test agent can be added to the angiogenesis assay system and
changes in angiogenesis relative to controls where no test agent is
added, identify candidate p53 modulating agents. In some
embodiments of the invention, the angiogenesis assay may be used as
a secondary assay to test a candidate p53 modulating agents that is
initially identified using another assay system. An angiogenesis
assay may also be used to test whether MSRA function plays a direct
role in cell proliferation. For example, an angiogenesis assay may
be performed on cells that over- or under-express MSRA relative to
wild type cells. Differences in angiogenesis compared to wild type
cells suggests that the MSRA plays a direct role in angiogenesis.
U.S. Pat. Nos. 5,976,782, 6,225,118 and 6,444,434, among others,
describe various angiogenesis assays.
[0084] Hypoxic induction. The alpha subunit of the transcription
factor, hypoxia inducible factor-1 (HIF-1), is upregulated in tumor
cells following exposure to hypoxia in vitro. Under hypoxic
conditions, HIF-1 stimulates the expression of genes known to be
important in tumour cell survival, such as those encoding glyolytic
enzymes and VEGF. Induction of such genes by hypoxic conditions may
be assayed by growing cells transfected with MSRA in hypoxic
conditions (such as with 0.1% O2, 5% CO2, and balance N2, generated
in a Napco 7001 incubator (Precision Scientific)) and normoxic
conditions, followed by assessment of gene activity or expression
by Taqman.RTM.. For example, a hypoxic induction assay system may
comprise a cell that expresses an MSRA, and that optionally has
defective p53 function (e.g. p53 is over-expressed or
under-expressed relative to wild-type cells). A test agent can be
added to the hypoxic induction assay system and changes in hypoxic
response relative to controls where no test agent is added,
identify candidate p53 modulating agents. In some embodiments of
the invention, the hypoxic induction assay may be used as a
secondary assay to test a candidate p53 modulating agents that is
initially identified using another assay system. A hypoxic
induction assay may also be used to test whether MSRA function
plays a direct role in the hypoxic response. For example, a hypoxic
induction assay may be performed on cells that over- or
under-express MSRA relative to wild type cells. Differences in
hypoxic response compared to wild type cells suggests that the MSRA
plays a direct role in hypoxic induction.
[0085] Cell adhesion. Cell adhesion assays measure adhesion of
cells to purified adhesion proteins, or adhesion of cells to each
other, in presence or absence of candidate modulating agents.
Cell-protein adhesion assays measure the ability of agents to
modulate the adhesion of cells to purified proteins. For example,
recombinant proteins are produced, diluted to 2.5 g/mL in PBS, and
used to coat the wells of a microtiter plate. The wells used for
negative control are not coated. Coated wells are then washed,
blocked with 1% BSA, and washed again. Compounds are diluted to
2.times. final test concentration and added to the blocked, coated
wells. Cells are then added to the wells, and the unbound cells are
washed off. Retained cells are labeled directly on the plate by
adding a membrane-permeable fluorescent dye, such as calcein-AM,
and the signal is quantified in a fluorescent microplate
reader.
[0086] Cell-cell adhesion assays measure the ability of agents to
modulate binding of cell adhesion proteins with their native
ligands. These assays use cells that naturally or recombinantly
express the adhesion protein of choice. In an exemplary assay,
cells expressing the cell adhesion protein are plated in wells of a
multiwell plate. Cells expressing the ligand are labeled with a
membrane-permeable fluorescent dye, such as BCECF, and allowed to
adhere to the monolayers in the presence of candidate agents.
Unbound cells are washed off, and bound cells are detected using a
fluorescence plate reader.
[0087] High-throughput cell adhesion assays have also been
described. In one such assay, small molecule ligands and peptides
are bound to the surface of microscope slides using a microarray
spotter, intact cells are then contacted with the slides, and
unbound cells are washed off. In this assay, not only the binding
specificity of the peptides and modulators against cell lines are
determined, but also the functional cell signaling of attached
cells using immunofluorescence techniques in situ on the microchip
is measured (Falsey J R et al., Bioconjug Chem. May-June
2001;12(3):346-53).
[0088] Tubulogenesis. Tubulogenesis assays monitor the ability of
cultured cells, generally endothelial cells, to form tubular
structures on a matrix substrate, which generally simulates the
environment of the extracellular matrix. Exemplary substrates
include Matrigel.TM. (Becton Dickinson), an extract of basement
membrane proteins containing laminin, collagen IV, and heparin
sulfate proteoglycan, which is liquid at 4.degree. C. and forms a
solid gel at 37.degree. C. Other suitable matrices comprise
extracellular components such as collagen, fibronectin, and/or
fibrin. Cells are stimulated with a pro-angiogenic stimulant, and
their ability to form tubules is detected by imaging. Tubules can
generally be detected after an overnight incubation with stimuli,
but longer or shorter time frames may also be used. Tube formation
assays are well known in the art (e.g., Jones M K et al., 1999,
Nature Medicine 5:1418-1423). These assays have traditionally
involved stimulation with serum or with the growth factors FGF or
VEGF. Serum represents an undefined source of growth factors. In a
preferred embodiment, the assay is performed with cells cultured in
serum free medium, in order to control which process or pathway a
candidate agent modulates. Moreover, we have found that different
target genes respond differently to stimulation with different
pro-angiogenic agents, including inflammatory angiogenic factors
such as TNF-alpa. Thus, in a further preferred embodiment, a
tubulogenesis assay system comprises testing an MSRA's response to
a variety of factors, such as FGF, VEGF, phorbol myristate acetate
(PMA), TNF-alpha, ephrin, etc.
[0089] Cell Migration. An invasion/migration assay (also called a
migration assay) tests the ability of cells to overcome a physical
barrier and to migrate towards pro-angiogenic signals. Migration
assays are known in the art (e.g., Paik J H et al., 2001, J Biol
Chem 276:11830-11837). In a typical experimental set-up, cultured
endothelial cells are seeded onto a matrix-coated porous lamina,
with pore sizes generally smaller than typical cell size. The
matrix generally simulates the environment of the extracellular
matrix, as described above. The lamina is typically a membrane,
such as the transwell polycarbonate membrane (Corning Costar
Corporation, Cambridge, Mass.), and is generally part of an upper
chamber that is in fluid contact with a lower chamber containing
pro-angiogenic stimuli. Migration is generally assayed after an
overnight incubation with stimuli, but longer or shorter time
frames may also be used. Migration is assessed as the number of
cells that crossed the lamina, and may be detected by staining
cells with hemotoxylin solution (VWR Scientific, South San
Francisco, Calif.), or by any other method for determining cell
number. In another exemplary set up, cells are fluorescently
labeled and migration is detected using fluorescent readings, for
instance using the Falcon HTS FluoroBlok (Becton Dickinson). While
some migration is observed in the absence of stimulus, migration is
greatly increased in response to pro-angiogenic factors. As
described above, a preferred assay system for migration/invasion
assays comprises testing an MSRA's response to a variety of
pro-angiogenic factors, including tumor angiogenic and inflammatory
angiogenic agents, and culturing the cells in serum free
medium.
[0090] Sprouting assay. A sprouting assay is a three-dimensional in
vitro angiogenesis assay that uses a cell-number defined spheroid
aggregation of endothelial cells ("spheroid"), embedded in a
collagen gel-based matrix. The spheroid can serve as a starting
point for the sprouting of capillary-like structures by invasion
into the extracellular matrix (termed "cell sprouting") and the
subsequent formation of complex anastomosing networks (Korff and
Augustin, 1999, J Cell Sci 112:3249-58). In an exemplary
experimental set-up, spheroids are prepared by pipetting 400 human
umbilical vein endothelial cells into individual wells of a
nonadhesive 96-well plates to allow overnight spheroidal
aggregation (Korff and Augustin: J Cell Biol 143: 1341-52, 1998).
Spheroids are harvested and seeded in 900 .mu.l of
methocel-collagen solution and pipetted into individual wells of a
24 well plate to allow collagen gel polymerization. Test agents are
added after 30 min by pipetting 100 .mu.l of 10-fold concentrated
working dilution of the test substances on top of the gel. Plates
are incubated at 37.degree. C. for 24 h. Dishes are fixed at the
end of the experimental incubation period by addition of
paraformaldehyde. Sprouting intensity of endothelial cells can be
quantitated by an automated image analysis system to determine the
cumulative sprout length per spheroid.
[0091] Primary Assays for Antibody Modulators
[0092] For antibody modulators, appropriate primary assays test is
a binding assay that tests the antibody's affinity to and
specificity for the MSRA protein. Methods for testing antibody
affinity and specificity are well known in the art (Harlow and
Lane, 1988, 1999, supra). The enzyme-linked immunosorbant assay
(ELISA) is a preferred method for detecting MSRA-specific
antibodies; others include FACS assays, radioimmunoassays, and
fluorescent assays.
[0093] In some cases, screening assays described for small molecule
modulators may also be used to test antibody modulators.
[0094] Primary Assays for Nucleic Acid Modulators
[0095] For nucleic acid modulators, primary assays may test the
ability of the nucleic acid modulator to inhibit or enhance MSRA
gene expression, preferably mRNA expression. In general, expression
analysis comprises comparing MSRA expression in like populations of
cells (e.g., two pools of cells that endogenously or recombinantly
express MSRA) in the presence and absence of the nucleic acid
modulator. Methods for analyzing mRNA and protein expression are
well known in the art. For instance, Northern blotting, slot
blotting, ribonuclease protection, quantitative RT-PCR (e.g., using
the TaqMan.RTM., PE Applied Biosystems), or microarray analysis may
be used to confirm that MSRA mRNA expression is reduced in cells
treated with the nucleic acid modulator (e.g., Current Protocols in
Molecular Biology (1994) Ausubel F M et al., eds., John Wiley &
Sons, Inc., chapter 4; Freeman W M et al., Biotechniques (1999)
26:112-125; Kallioniemi O P, Ann Med 2001, 33:142-147; Blohm D H
and Guiseppi-Elie, A Curr Opin Biotechnol 2001, 12:41-47). Protein
expression may also be monitored. Proteins are most commonly
detected with specific antibodies or antisera directed against
either the MSRA protein or specific peptides. A variety of means
including Western blotting, ELISA, or in situ detection, are
available (Harlow E and Lane D, 1988 and 1999, supra).
[0096] In some cases, screening assays described for small molecule
modulators, particularly in assay systems that involve MSRA mRNA
expression, may also be used to test nucleic acid modulators.
[0097] Secondary Assays
[0098] Secondary assays may be used to further assess the activity
of MSRA-modulating agent identified by any of the above methods to
confirm that the modulating agent affects MSRA in a manner relevant
to the p53 pathway. As used herein, MSRA-modulating agents
encompass candidate clinical compounds or other agents derived from
previously identified modulating agent. Secondary assays can also
be used to test the activity of a modulating agent on a particular
genetic or biochemical pathway or to test the specificity of the
modulating agent's interaction with MSRA.
[0099] Secondary assays generally compare like populations of cells
or animals (e.g., two pools of cells or animals that endogenously
or recombinantly express MSRA) in the presence and absence of the
candidate modulator. In general, such assays test whether treatment
of cells or animals with a candidate MSRA-modulating agent results
in changes in the p53 pathway in comparison to untreated (or mock-
or placebo-treated) cells or animals. Certain assays use
"sensitized genetic backgrounds", which, as used herein, describe
cells or animals engineered for altered expression of genes in the
p53 or interacting pathways.
[0100] Cell-Based Assays
[0101] Cell based assays may use a variety of mammalian cell lines
known to have defective p53 function (e.g. SAOS-2 osteoblasts,
H1299 lung cancer cells, C33A and HT3 cervical cancer cells, HT-29
and DLD-1 colon cancer cells, among others, available from American
Type Culture Collection (ATCC), Manassas, Va.). Cell based assays
may detect endogenous p53 pathway activity or may rely on
recombinant expression of p53 pathway components. Any of the
aforementioned assays may be used in this cell-based format.
Candidate modulators are typically added to the cell media but may
also be injected into cells or delivered by any other efficacious
means.
[0102] Animal Assays
[0103] A variety of non-human animal models of normal or defective
p53 pathway may be used to test candidate MSRA modulators. Models
for defective p53 pathway typically use genetically modified
animals that have been engineered to mis-express (e.g.,
over-express or lack expression in) genes involved in the p53
pathway. Assays generally require systemic delivery of the
candidate modulators, such as by oral administration, injection,
etc.
[0104] In a preferred embodiment, p53 pathway activity is assessed
by monitoring neovascularization and angiogenesis. Animal models
with defective and normal p53 are used to test the candidate
modulator's affect on MSRA in Matrigel.RTM. assays. Matrigel.RTM.
is an extract of basement membrane proteins, and is composed
primarily of laminin, collagen IV, and heparin sulfate
proteoglycan. It is provided as a sterile liquid at 4.degree. C.,
but rapidly forms a solid gel at 37.degree. C. Liquid Matrigel.RTM.
is mixed with various angiogenic agents, such as bFGF and VEGF, or
with human tumor cells which over-express the MSRA. The mixture is
then injected subcutaneously (SC) into female athymic nude mice
(Taconic, Germantown, N.Y.) to support an intense vascular
response. Mice with Matrigel.RTM. pellets may be dosed via oral
(PO), intraperitoneal (IP), or intravenous (IV) routes with the
candidate modulator. Mice are euthanized 5-12 days post-injection,
and the Matrigel.RTM. pellet is harvested for hemoglobin analysis
(Sigma plasma hemoglobin kit). Hemoglobin content of the gel is
found to correlate the degree of neovascularization in the gel.
[0105] In another preferred embodiment, the effect of the candidate
modulator on MSRA is assessed via tumorigenicity assays. Tumor
xenograft assays are known in the art (see, e.g., Ogawa K et al.,
2000, Oncogene 19:6043-6052). Xenografts are typically implanted SC
into female athymic mice, 6-7 week old, as single cell suspensions
either from a pre-existing tumor or from in vitro culture. The
tumors which express the MSRA endogenously are injected in the
flank, 1.times.10.sup.5 to 1.times.10.sup.7 cells per mouse in a
volume of 100 .mu.L using a 27 gauge needle. Mice are then ear
tagged and tumors are measured twice weekly. Candidate modulator
treatment is initiated on the day the mean tumor weight reaches 100
mg. Candidate modulator is delivered IV, SC, IP, or PO by bolus
administration. Depending upon the pharmacokinetics of each unique
candidate modulator, dosing can be performed multiple times per
day. The tumor weight is assessed by measuring perpendicular
diameters with a caliper and calculated by multiplying the
measurements of diameters in two dimensions. At the end of the
experiment, the excised tumors maybe utilized for biomarker
identification or further analyses. For immunohistochemistry
staining, xenograft tumors are fixed in 4% paraformaldehyde, 0.1M
phosphate, pH 7.2, for 6 hours at 4.degree. C., immersed in 30%
sucrose in PBS, and rapidly frozen in isopentane cooled with liquid
nitrogen.
[0106] In another preferred embodiment, tumorogenicity is monitored
using a hollow fiber assay, which is described in U.S. Pat. No.
5,698,413. Briefly, the method comprises implanting into a
laboratory animal a biocompatible, semi-permeable encapsulation
device containing target cells, treating the laboratory animal with
a candidate modulating agent, and evaluating the target cells for
reaction to the candidate modulator. Implanted cells are generally
human cells from a pre-existing tumor or a tumor cell line. After
an appropriate period of time, generally around six days, the
implanted samples are harvested for evaluation of the candidate
modulator. Tumorogenicity and modulator efficacy may be evaluated
by assaying the quantity of viable cells present in the
macrocapsule, which can be determined by tests known in the art,
for example, MTT dye conversion assay, neutral red dye uptake,
trypan blue staining, viable cell counts, the number of colonies
formed in soft agar, the capacity of the cells to recover and
replicate in vitro, etc.
[0107] In another preferred embodiment, a tumorogenicity assay use
a transgenic animal, usually a mouse, carrying a dominant oncogene
or tumor suppressor gene knockout under the control of tissue
specific regulatory sequences; these assays are generally referred
to as transgenic tumor assays. In a preferred application, tumor
development in the transgenic model is well characterized or is
controlled. In an exemplary model, the "RIP1-Tag2" transgene,
comprising the SV40 large T-antigen oncogene under control of the
insulin gene regulatory regions is expressed in pancreatic beta
cells and results in islet cell carcinomas (Hanahan D, 1985, Nature
315:115-122; Parangi S et al, 1996, Proc Natl Acad Sci USA 93:
2002-2007; Bergers G et al, 1999, Science 284:808-812). An
"angiogenic switch," occurs at approximately five weeks, as
normally quiescent capillaries in a subset of hyperproliferative
islets become angiogenic. The RIP1-TAG2 mice die by age 14 weeks.
Candidate modulators may be administered at a variety of stages,
including just prior to the angiogenic switch (e.g., for a model of
tumor prevention), during the growth of small tumors (e.g., for a
model of intervention), or during the growth of large and/or
invasive tumors (e.g., for a model of regression). Tumorogenicity
and modulator efficacy can be evaluating life-span extension and/or
tumor characteristics, including number of tumors, tumor size,
tumor morphology, vessel density, apoptotic index, etc.
[0108] Diagnostic and Therapeutic Uses
[0109] Specific MSRA-modulating agents are useful in a variety of
diagnostic and therapeutic applications where disease or disease
prognosis is related to defects in the p53 pathway, such as
angiogenic, apoptotic, or cell proliferation disorders.
Accordingly, the invention also provides methods for modulating the
p53 pathway in a cell, preferably a cell pre-determined to have
defective or impaired p53 function (e.g. due to overexpression,
underexpression, or misexpression of p53, or due to gene
mutations), comprising the step of administering an agent to the
cell that specifically modulates MSRA activity. Preferably, the
modulating agent produces a detectable phenotypic change in the
cell indicating that the p53 function is restored. The phrase
"function is restored", and equivalents, as used herein, means that
the desired phenotype is achieved, or is brought closer to normal
compared to untreated cells. For example, with restored p53
function, cell proliferation and/or progression through cell cycle
may normalize, or be brought closer to normal relative to untreated
cells. The invention also provides methods for treating disorders
or disease associated with impaired p53 function by administering a
therapeutically effective amount of an MSRA-modulating agent that
modulates the p53 pathway. The invention further provides methods
for modulating MSRA function in a cell, preferably a cell
pre-determined to have defective or impaired MSRA function, by
administering an MSRA-modulating agent. Additionally, the invention
provides a method for treating disorders or disease associated with
impaired MSRA function by administering a therapeutically effective
amount of an MSRA-modulating agent.
[0110] The discovery that MSRA is implicated in p53 pathway
provides for a variety of methods that can be employed for the
diagnostic and prognostic evaluation of diseases and disorders
involving defects in the p53 pathway and for the identification of
subjects having a predisposition to such diseases and
disorders.
[0111] Various expression analysis methods can be used to diagnose
whether MSRA expression occurs in a particular sample, including
Northern blotting, slot blotting, ribonuclease protection,
quantitative RT-PCR, and microarray analysis. (e.g., Current
Protocols in Molecular Biology (1994) Ausubel F M et al., eds.,
John Wiley & Sons, Inc., chapter 4; Freeman W M et al.,
Biotechniques (1999) 26:112-125; Kallioniemi O P, Ann Med 2001,
33:142-147; Blohm and Guiseppi-Elie, Curr Opin Biotechnol 2001,
12:41-47). Tissues having a disease or disorder implicating
defective p53 signaling that express an MSRA, are identified as
amenable to treatment with an MSRA modulating agent. In a preferred
application, the p53 defective tissue overexpresses an MSRA
relative to normal tissue. For example, a Northern blot analysis of
mRNA from tumor and normal cell lines, or from tumor and matching
normal tissue samples from the same patient, using full or partial
MSRA cDNA sequences as probes, can determine whether particular
tumors express or overexpress MSRA. Alternatively, the TaqMan.RTM.
is used for quantitative RT-PCR analysis of MSRA expression in cell
lines, normal tissues and tumor samples (PE Applied
Biosystems).
[0112] Various other diagnostic methods may be performed, for
example, utilizing reagents such as the MSRA oligonucleotides, and
antibodies directed against an MSRA, as described above for: (1)
the detection of the presence of MSRA gene mutations, or the
detection of either over- or under-expression of MSRA mRNA relative
to the non-disorder state; (2) the detection of either an over- or
an under-abundance of MSRA gene product relative to the
non-disorder state; and (3) the detection of perturbations or
abnormalities in the signal transduction pathway mediated by
MSRA.
[0113] Thus, in a specific embodiment, the invention is drawn to a
method for diagnosing a disease or disorder in a patient that is
associated with alterations in MSRA expression, the method
comprising: a) obtaining a biological sample from the patient; b)
contacting the sample with a probe for MSRA expression; c)
comparing results from step (b) with a control; and d) determining
whether step (c) indicates a likelihood of the disease or disorder.
Preferably, the disease is cancer, most preferably skin cancer. The
probe may be either DNA or protein, including an antibody.
EXAMPLES
[0114] The following experimental section and examples are offered
by way of illustration and not by way of limitation.
I. Drosophila p53 Screen
[0115] The Drosophila p53 gene was overexpressed specifically in
the wing using the vestigial margin quadrant enhancer. Increasing
quantities of Drosophila p53 (titrated using different strength
transgenic inserts in 1 or 2 copies) caused deterioration of normal
wing morphology from mild to strong, with phenotypes including
disruption of pattern and polarity of wing hairs, shortening and
thickening of wing veins, progressive crumpling of the wing and
appearance of dark "death" inclusions in wing blade. In a screen
designed to identify enhancers and suppressors of Drosophila p53,
homozygous females carrying two copies of p53 were crossed to 5663
males carrying random insertions of a piggyBac transposon (Fraser M
et al., Virology (1985) 145:356-361). Progeny containing insertions
were compared to non-insertion-bearing sibling progeny for
enhancement or suppression of the p53 phenotypes. Sequence
information surrounding the piggyBac insertion site was used to
identify the modifier genes. Modifiers of the wing phenotype were
identified as members of the p53 pathway. CG7266 was an enhancer of
the wing phenotype. Orthologs of the modifiers are referred to
herein as MSRA.
[0116] BLAST analysis (Altschul et al., supra) was employed to
identify orthologs of Drosophila modifiers. For example, a
representative sequence from MSRA, GI# 6912516 (SEQ ID NO:4),
shares 40% amino acid identity with the Drosophila CG7266.
[0117] Various domains, signals, and functional subunits in
proteins were analyzed using the PSORT (Nakai K., and Horton P.,
Trends Biochem Sci, 1999, 24:34-6; Kenta Nakai, Protein sorting
signals and prediction of subcellular localization, Adv. Protein
Chem. 54, 277-344 (2000)), PFAM (Bateman A., et al., Nucleic Acids
Res, 1999, 27:260-2), SMART (Ponting C P, et al., SMART:
identification and annotation of domains from signaling and
extracellular protein sequences. Nucleic Acids Res. Jan. 1,
1999;27(1):229-32), TM-HMM (Erik L. L. Sonnhammer, Gunnar von
Heijne, and Anders Krogh: A hidden Markov model for predicting
transmembrane helices in protein sequences. In Proc. of Sixth Int.
Conf. on Intelligent Systems for Molecular Biology, p 175-182 Ed J.
Glasgow, T. Littlejohn, F. Major, R. Lathrop, D. Sankoff, and C.
Sensen Menlo Park, Calif.: AAAI Press, 1998), and clust (Remm M,
and Sonnhammer E. Classification of transmembrane protein families
in the Caenorhabditis elegans genome and identification of human
orthologs. Genome Res. November 2000;10(11):1679-89) programs. For
example, the peptide methionine sulfoxide reductase domain (PFAM
01625) of MSRA from GI# 6912516 (SEQ ID NO:4) is located at
approximately amino acid residues 52 to 200.
II. High-Throughput In Vitro Fluorescence Polarization Assay
[0118] Fluorescently-labeled MSRA peptide/substrate are added to
each well of a 96-well microtiter plate, along with a test agent in
a test buffer (10 mM HEPES, 10 mM NaCl, 6 mM magnesium chloride, pH
7.6). Changes in fluorescence polarization, determined by using a
Fluorolite FPM-2 Fluorescence Polarization Microtiter System
(Dynatech Laboratories, Inc), relative to control values indicates
the test compound is a candidate modifier of MSRA activity.
III. High-Throughput In Vitro Binding Assay
[0119] .sup.33P-labeled MSRA peptide is added in an assay buffer
(100 mM KCl, 20 mM HEPES pH 7.6, 1 mM MgCl.sub.2, 1% glycerol, 0.5%
NP-40, 50 mM beta-mercaptoethanol, 1 mg/ml BSA, cocktail of
protease inhibitors) along with a test agent to the wells of a
Neutralite-avidin coated assay plate and incubated at 25.degree. C.
for 1 hour. Biotinylated substrate is then added to each well and
incubated for 1 hour. Reactions are stopped by washing with PBS,
and counted in a scintillation counter. Test agents that cause a
difference in activity relative to control without test agent are
identified as candidate p53 modulating agents.
IV. Immunoprecipitations and Immunoblotting
[0120] For coprecipitation of transfected proteins,
3.times.10.sup.6 appropriate recombinant cells containing the MSRA
proteins are plated on 10-cm dishes and transfected on the
following day with expression constructs. The total amount of DNA
is kept constant in each transfection by adding empty vector. After
24 h, cells are collected, washed once with phosphate-buffered
saline and lysed for 20 min on ice in 1 ml of lysis buffer
containing 50 mM Hepes, pH 7.9, 250 mM NaCl, 20
mM-glycerophosphate, 1 mM sodium orthovanadate, 5 mM p-nitrophenyl
phosphate, 2 mM dithiothreitol, protease inhibitors (complete,
Roche Molecular Biochemicals), and 1% Nonidet P-40. Cellular debris
is removed by centrifugation twice at 15,000.times.g for 15 min.
The cell lysate is incubated with 25 .mu.l of M2 beads (Sigma) for
2 h at 4.degree. C. with gentle rocking.
[0121] After extensive washing with lysis buffer, proteins bound to
the beads are solubilized by boiling in SDS sample buffer,
fractionated by SDS-polyacrylamide gel electrophoresis, transferred
to polyvinylidene difluoride membrane and blotted with the
indicated antibodies. The reactive bands are visualized with
horseradish peroxidase coupled to the appropriate secondary
antibodies and the enhanced chemiluminescence (ECL) Western
blotting detection system (Amersham Pharrnacia Biotech).
V. Expression Analysis
[0122] All cell lines used in the following experiments are NCI
(National Cancer Institute) lines, and are available from ATCC
(American Type Culture Collection, Manassas, Va. 20110-2209).
Normal and tumor tissues were obtained from Impath, UC Davis,
Clontech, Stratagene, Ardais, Genome Collaborative, and Ambion.
[0123] TaqMan analysis was used to assess expression levels of the
disclosed genes in various samples.
[0124] RNA was extracted from each tissue sample using Qiagen
(Valencia, Calif.) RNeasy kits, following manufacturer's protocols,
to a final concentration of 50 ng/.mu.l. Single stranded cDNA was
then synthesized by reverse transcribing the RNA samples using
random hexamers and 500 ng of total RNA per reaction, following
protocol 4304965 of Applied Biosystems (Foster City, Calif.).
[0125] Primers for expression analysis using TaqMan assay (Applied
Biosystems, Foster City, Calif.) were prepared according to the
TaqMan protocols, and the following criteria: a) primer pairs were
designed to span introns to eliminate genomic contamination, and b)
each primer pair produced only one product. Expression analysis was
performed using a 7900HT instrument.
[0126] Taqman reactions were carried out following manufacturer's
protocols, in 25 .mu.l total volume for 96-well plates and 10 .mu.l
total volume for 384-well plates, using 300 nM primer and 250 nM
probe, and approximately 25 ng of cDNA. The standard curve for
result analysis was prepared using a universal pool of human cDNA
samples, which is a mixture of cDNAs from a wide variety of tissues
so that the chance that a target will be present in appreciable
amounts is good. The raw data were normalized using 18S rRNA
(universally expressed in all tissues and cells).
[0127] For each expression analysis, tumor tissue samples were
compared with matched normal tissues from the same patient. A gene
was considered overexpressed in a tumor when the level of
expression of the gene was 2 fold or higher in the tumor compared
with its matched normal sample. In cases where normal tissue was
not available, a universal pool of cDNA samples was used instead.
In these cases, a gene was considered overexpressed in a tumor
sample when the difference of expression levels between a tumor
sample and the average of all normal samples from the same tissue
type was greater than 2 times the standard deviation of all normal
samples (i.e., Tumor-average(all normal samples)>2.times.STDEV(-
all normal samples)).
[0128] MSRA was overexpressed in 67% (3 pairs) of skin cancers. A
modulator identified by an assay described herein can be further
validated for therapeutic effect by administration to a tumor in
which the gene is overexpressed. A decrease in tumor growth
confirms therapeutic utility of the modulator. Prior to treating a
patient with the modulator, the likelihood that the patient will
respond to treatment can be diagnosed by obtaining a tumor sample
from the patient, and assaying for expression of the gene targeted
by the modulator. The expression data for the gene(s) can also be
used as a diagnostic marker for disease progression. The assay can
be performed by expression analysis as described above, by antibody
directed to the gene target, or by any other available detection
method.
Sequence CWU 1
1
4 1 1502 DNA Homo sapiens 1 gcggccgcgt cgacgtgaca gccggtacgc
ccgggtttgg gcaacctcga ttacgggcgg 60 cctccaggcc cgccagcagc
gccccgcgcc gcccgcccgc gcccctgccg ccccccggtt 120 ccggccgcgg
accccactct ctgccgttcc ggctgcggct ccgctgccgg tagcgccgtc 180
ccccgggacc acccttcggc tggcgccctc ccatgctctc ggccacccgg agggcttgcc
240 agctcctcct cctccacagc ctctttcccg tcccgaggat gggcaactcg
gcctcgaaca 300 tcgtcagccc ccaggaggcc ttgccgggcc ggaaggaaca
gacccctgta gcggccaaac 360 atcatgtcaa tggcaacaga acagtcgaac
ctttcccaga gggaacacag atggctgtat 420 ttggaatggg atgtttctgg
ggagctgaaa ggaaattctg ggtcttgaaa ggagtgtatt 480 caactcaagt
tggttttgca ggaggctata cttcaaatcc tacttataaa gaagtctgct 540
cagaaaaaac tggccatgca gaagtcgtcc gagtggtgta ccagccagaa cacatgagtt
600 ttgaggaact gctcaaggtc ttctgggaga atcacgaccc gacccaaggt
atgcgccagg 660 ggaacgacca tggcactcag taccgctcgg ccatctaccc
gacctctgcc aagcaaatgg 720 aggcagccct gagctccaaa gagaactacc
aaaaggttct ttcagagcac ggcttcggcc 780 ccatcactac cgacatccgg
gagggacaga ctttctacta tgcggaagac taccaccagc 840 agtacctgag
caagaacccc aatggctact gcggccttgg gggcaccggc gtgtcctgcc 900
cagtgggtat taaaaaataa ttgctcccca catggtgggc ctttgaggtt ccagtaaaaa
960 tgctttcaac aaattgggca atgcttgtgt gattcacaat cgtggcattt
aaagtgcaca 1020 aagtacaaag gaatttatac agattgggtt taccgaagta
taatctatag gaggcgcgat 1080 ggcaagttga taaaatgtga cttatctcct
aataagttat ggtgggagtg gagctgtgcg 1140 gtttcctgtg tcttctgggg
tctgagtgaa gatagcaggg atgctgtgtt cacccttctt 1200 ggtagaagct
aaggtgtgag ctgggaggtt gctggacagg atgggggacc ccagaagtcc 1260
tttatctgtg ctctctgccc gccagtgcct tacaatttgc aaacgtgtat agcctcagtg
1320 actcattcgc tgaaatcctt cgctttacca aatctagaca tacataaggg
ctttctctcc 1380 cttttcagcc ctctctgtgc agagaaaaga tgtgagtccg
cttgatgaat tctaatgctt 1440 tgcttagagc tatgagaaat gtttgtttta
ataaaaacct acagtccaat aaaaaaaaaa 1500 aa 1502 2 1343 DNA Homo
sapiens 2 gtccggctgc ggctccgctg ccggtagcgc cgtcccccgg gaccaccctt
cggctggcgc 60 cctcccatgc tctcggccac ccggagggct tgccagctcc
acagcctctt tcccgtcccg 120 aggatgggca actcggcctc gaacatcgtc
agcccccagg aggccttgcc gggccggaag 180 gaacagaccc ctgtagcggc
caaacatcat gtcaatggca acagaacagt cgaacctttc 240 ccagagggaa
cacagatggc tgtatttgga atgggatgtt tctggggagc tgaaaggaaa 300
ttctgggtct tgaaaggagt gtattcaact caagttggtt ttgcaggagg ctatacttca
360 aatcctactt ataaagaagt ctgctcagaa aaaactggcc atgcagaagt
cgtccgagtg 420 gtgtaccagc cagaacacat gagttttgag gaactgtcaa
ggctttggga gaatcacgac 480 ccgacccaag gtatgcgcca ggggaacgac
catggcactc agtaccgttc ggccatctac 540 ccgacctctg ccaagcaaat
ggaggcagcc ctgagctcca aagagaacta ccaaaaggtt 600 ctttcagagc
acggcttcgg ccccatcact accgacatcc gggagggaca gactttctac 660
tatgcggaag actaccacca gcagtacctg agcaagaacc ccaatggcta ctgcggcctt
720 gggggcaccg gcgtgtcctg cccagtgggt attaaaaaat aattgctccc
cacatggtgg 780 gcctttgagg ttccagtaaa aatgctttca acaaattggg
caatgcttgt gtgattcaca 840 atcgtggcat ttaaagtgca caagtacaaa
ggaatttata cagattgggt ttaccgaagt 900 ataatctata ggaggcgcga
tggcaagttg ataaaatgtg acttatctcc taataagtta 960 tggtgggagt
ggagctgtgc ggtttcctgt gtcttctggg gtctgagtga agatagcagg 1020
gatgctgtgt tcacccttct tggtagaagc taaggtgtga gctgggaggt tgctggacag
1080 gatgggggac cccagaagtc ctttatctgt gctctctgcc cgccagtgcc
ttacaatttg 1140 caaacgtgta tagcctcagt gactcattcg ctgaaatcct
tcgctttacc aaatctagac 1200 atacataagg gctttctctc ccttttcagc
cctctctgtg cagagaaaag atgtgagtcc 1260 gcttgatgaa ttctaatgct
ttgcttagag ctatgagaaa tgtttgtttt aataaaaacc 1320 tacagtccaa
taaaaaaaaa aaa 1343 3 1482 DNA Homo sapiens 3 gtgacagccg gtacggcccc
gggtttgggc aacctcgatt acgggcggcc tccagccccg 60 ccagcagcgc
cccgcgcccg cccgcccgcg cccctgccgc cccccggttc cggccgcgga 120
ccccactctc tgccgttccg gctgcggctc cgctgccggt agcgccgtcc cccgggacca
180 cccttcggct ggcgccctcc catgctctcg gccacccgga gggcttgcca
gctcctcctc 240 ctccacagcc tctttcccgt cccgaggatg ggcaactcgg
cctcgaacat cgtcagcccc 300 caggaggcct tgccgggccg gaaggaacag
acccctgtag cggccaaaca tcatgtcaat 360 ggcaacagaa cagtcgaacc
tttcccagag ggaacacaga tggctgtatt tggaatggga 420 tgtttctggg
gagctgaaag gaaattctgg gtcttgaaag gagtgtattc aactcaagtt 480
ggttttgcag gaggctatac ttcaaatcct acttataaag aagtctgctc agaaaaaact
540 ggccatgcag aagtcgtccg agtggtgtac cagccagaac acatgagttt
tgaggaactg 600 ctcaaggtct tctgggagaa tcacgacccg acccaaggta
tgcgccaggg gaacgaccat 660 ggcactcagt accgctcggc catctacccg
acctctgcca agcaaatgga ggcagccctg 720 agctccaaag agaactacca
aaaggttctt tcagagcacg gcttcggccc catcactacc 780 gacatccggg
agggacagac tttctactat gcggaagact accaccagca gtacctgagc 840
aagaacccca atggctactg cggccttggg ggcaccggcg tgtcctgccc agtgggtatt
900 aaaaaataat ttctccccac atggtgggcc tttgaggttc cagtaaaaat
gctttcaaca 960 aattgggcaa tgcttgtgtg attcacaatc gtggcattta
aagtgcacaa agtacaaagg 1020 aatttataca gattgggttt accgaagtat
aatctatagg aggcgcgatg gcaagttgat 1080 aaaatgtgac ttatctccta
ataagttatg gtgggagtgg agctgtgcag tttcctgtgt 1140 cttctggggt
ctgagtgaag atagcaggga tgctgtgttc acccttcttg gtagaagcta 1200
aggtgtgagc tgggaggttg ctggacagga tgggggaccc cagaagtcct ttatctgtgc
1260 tctctgcccg ccagtgcctt acaatttgca aacgtgtata gcctcagtga
ctcattcgct 1320 gaaatccttc gctttaccaa atctagacat acataagggg
ctttctctcc cttttcagcc 1380 ctctctgtgc agagaaaaga tgtgagtccg
cttgatgaat tctaatgctt tgcttagagc 1440 tatgagaaat gtttgtttta
ataaaaacct acagtccaat aa 1482 4 235 PRT Homo sapiens 4 Met Leu Ser
Ala Thr Arg Arg Ala Cys Gln Leu Leu Leu Leu His Ser 1 5 10 15 Leu
Phe Pro Val Pro Arg Met Gly Asn Ser Ala Ser Asn Ile Val Ser 20 25
30 Pro Gln Glu Ala Leu Pro Gly Arg Lys Glu Gln Thr Pro Val Ala Ala
35 40 45 Lys His His Val Asn Gly Asn Arg Thr Val Glu Pro Phe Pro
Glu Gly 50 55 60 Thr Gln Met Ala Val Phe Gly Met Gly Cys Phe Trp
Gly Ala Glu Arg 65 70 75 80 Lys Phe Trp Val Leu Lys Gly Val Tyr Ser
Thr Gln Val Gly Phe Ala 85 90 95 Gly Gly Tyr Thr Ser Asn Pro Thr
Tyr Lys Glu Val Cys Ser Glu Lys 100 105 110 Thr Gly His Ala Glu Val
Val Arg Val Val Tyr Gln Pro Glu His Met 115 120 125 Ser Phe Glu Glu
Leu Leu Lys Val Phe Trp Glu Asn His Asp Pro Thr 130 135 140 Gln Gly
Met Arg Gln Gly Asn Asp His Gly Thr Gln Tyr Arg Ser Ala 145 150 155
160 Ile Tyr Pro Thr Ser Ala Lys Gln Met Glu Ala Ala Leu Ser Ser Lys
165 170 175 Glu Asn Tyr Gln Lys Val Leu Ser Glu His Gly Phe Gly Pro
Ile Thr 180 185 190 Thr Asp Ile Arg Glu Gly Gln Thr Phe Tyr Tyr Ala
Glu Asp Tyr His 195 200 205 Gln Gln Tyr Leu Ser Lys Asn Pro Asn Gly
Tyr Cys Gly Leu Gly Gly 210 215 220 Thr Gly Val Ser Cys Pro Val Gly
Ile Lys Lys 225 230 235
* * * * *