U.S. patent application number 09/925140 was filed with the patent office on 2003-09-04 for serine dehydratase homolog.
This patent application is currently assigned to Incyte Pharmaceuticals, Inc.. Invention is credited to Corley, Neil C., Guegler, Karl J., Lal, Preeti, Patterson, Chandra.
Application Number | 20030166199 09/925140 |
Document ID | / |
Family ID | 22211357 |
Filed Date | 2003-09-04 |
United States Patent
Application |
20030166199 |
Kind Code |
A1 |
Lal, Preeti ; et
al. |
September 4, 2003 |
Serine dehydratase homolog
Abstract
The invention provides a human serine dehydratase homolog (SDHH)
and polynucleotides which identify and encode SDHH. The invention
also provides expression vectors, host cells, antibodies, agonists,
and antagonists. The invention also provides methods for
diagnosing, treating or preventing disorders associated with
expression of SDHH.
Inventors: |
Lal, Preeti; (Santa Clara,
CA) ; Corley, Neil C.; (Mountain View, CA) ;
Guegler, Karl J.; (Menlo Park, CA) ; Patterson,
Chandra; (Mountain View, CA) |
Correspondence
Address: |
INCYTE CORPORATION (formerly known as Incyte
Genomics, Inc.)
3160 PORTER DRIVE
PALO ALTO
CA
94304
US
|
Assignee: |
Incyte Pharmaceuticals,
Inc.
|
Family ID: |
22211357 |
Appl. No.: |
09/925140 |
Filed: |
August 8, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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09925140 |
Aug 8, 2001 |
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09088435 |
Jun 1, 1998 |
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6277619 |
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Current U.S.
Class: |
435/190 ;
435/252.3; 435/325; 435/69.1; 536/23.2; 800/8 |
Current CPC
Class: |
A61K 38/00 20130101;
C12N 9/88 20130101 |
Class at
Publication: |
435/190 ;
435/252.3; 435/325; 800/8; 435/69.1; 536/23.2 |
International
Class: |
A01K 067/00; C07H
021/04; C12N 009/04; C12P 021/02; C12N 005/06; C12N 001/21 |
Claims
What is claimed is:
1. An isolated polypeptide selected from the group consisting of:
a) a polypeptide comprising an amino acid sequence of SEQ ID NO:1,
b) a polypeptide comprising a naturally occurring amino acid
sequence at least 90% identical to an amino acid sequence of SEQ ID
NO:1, c) a biologically active fragment of a polypeptide having an
amino acid sequence of SEQ ID NO:1, and d) an immunogenic fragment
of a polypeptide having an amino acid sequence of SEQ ID NO:1.
2. An isolated polypeptide of claim 1 having an amino acid sequence
of SEQ ID NO:1.
3. An isolated polynucleotide encoding a polypeptide of claim
1.
4. An isolated polynucleotide encoding a polypeptide of claim
2.
5. An isolated polynucleotide of claim 4 having a polynucleotide
sequence of SEQ ID NO:2.
6. A recombinant polynucleotide comprising a promoter sequence
operably linked to a polynucleotide of claim 3.
7. A cell transformed with a recombinant polynucleotide of claim
6.
8. A transgenic organism comprising a recombinant polynucleotide of
claim 6.
9. A method of producing a polypeptide of claim 1, the method
comprising: a) culturing a cell under conditions suitable for
expression of the polypeptide, wherein said cell is transformed
with a recombinant polynucleotide, and said recombinant
polynucleotide comprises a promoter sequence operably linked to a
polynucleotide encoding the polypeptide of claim 1, and b)
recovering the polypeptide so expressed.
10. An isolated antibody which specifically binds to a polypeptide
of claim 1.
11. An isolated polynucleotide selected from the group consisting
of: a) a polynucleotide comprising a polynucleotide sequence of SEQ
ID NO:2, b) a polynucleotide comprising a naturally occurring
polynucleotide sequence at least 90% identical to a polynucleotide
sequence of SEQ ID NO:2, c) a polynucleotide complementary to a
polynucleotide of a), d) a polynucleotide complementary to a
polynucleotide of b), and e) an RNA equivalent of a)-d).
12. An isolated polynucleotide comprising at least 60 contiguous
nucleotides of a polynucleotide of claim 11.
13. A method of detecting a target polynucleotide in a sample, said
target polynucleotide having a sequence of a polynucleotide of
claim 11, the method comprising: a) hybridizing the sample with a
probe comprising at least 20 contiguous nucleotides comprising a
sequence complementary to said target polynucleotide in the sample,
and which probe specifically hybridizes to said target
polynucleotide, under conditions whereby a hybridization complex is
formed between said probe and said target polynucleotide or
fragments thereof, and b) detecting the presence or absence of said
hybridization complex, and, optionally, if present, the amount
thereof.
14. A method of claim 13, wherein the probe comprises at least 60
contiguous nucleotides.
15. A method of detecting a target polynucleotide in a sample, said
target polynucleotide having a sequence of a polynucleotide of
claim 11, the method comprising: a) amplifying said target
polynucleotide or fragment thereof using polymerase chain reaction
amplification, and b) detecting the presence or absence of said
amplified target polynucleotide or fragment thereof, and,
optionally, if present, the amount thereof.
16. A composition comprising a polypeptide of claim 1 and a
pharmaceutically acceptable excipient.
17. A composition of claim 16, wherein the polypeptide has an amino
acid sequence of SEQ ID NO:1.
18. A method for treating a disease or condition associated with
decreased expression of functional SDHH, comprising administering
to a patient in need of such treatment the composition of claim
16.
19. A method of screening a compound for effectiveness as an
agonist of a polypeptide of claim 1, the method comprising: a)
exposing a sample comprising a polypeptide of claim 1 to a
compound, and b) detecting agonist activity in the sample.
20. A composition comprising an agonist compound identified by a
method of claim 19 and a pharmaceutically acceptable excipient.
21. A method for treating a disease or condition associated with
decreased expression of functional SDHH, comprising administering
to a patient in need of such treatment a composition of claim
20.
22. A method of screening a compound for effectiveness as an
antagonist of a polypeptide of claim 1, the method comprising: a)
exposing a sample comprising a polypeptide of claim 1 to a
compound, and b) detecting antagonist activity in the sample.
23. A composition comprising an antagonist compound identified by a
method of claim 22 and a pharmaceutically acceptable excipient.
24. A method for treating a disease or condition associated with
overexpression of functional SDHH, comprising administering to a
patient in need of such treatment a composition of claim 23.
25. A method of screening for a compound that specifically binds to
the polypeptide of claim 1, the method comprising: a) combining the
polypeptide of claim 1 with at least one test compound under
suitable conditions, and b) detecting binding of the polypeptide of
claim 1 to the test compound, thereby identifying a compound that
specifically binds to the polypeptide of claim 1.
26. A method of screening for a compound that modulates the
activity of the polypeptide of claim 1, the method comprising: a)
combining the polypeptide of claim 1 with at least one test
compound under conditions permissive for the activity of the
polypeptide of claim 1, b) assessing the activity of the
polypeptide of claim 1 in the presence of the test compound, and c)
comparing the activity of the polypeptide of claim 1 in the
presence of the test compound with the activity of the polypeptide
of claim 1 in the absence of the test compound, wherein a change in
the activity of the polypeptide of claim 1 in the presence of the
test compound is indicative of a compound that modulates the
activity of the polypeptide of claim 1.
27. A method of screening a compound for effectiveness in altering
expression of a target polynucleotide, wherein said target
polynucleotide comprises a sequence of claim 5, the method
comprising: a) exposing a sample comprising the target
polynucleotide to a compound, under conditions suitable for the
expression of the target polynucleotide, b) detecting altered
expression of the target polynucleotide, and c) comparing the
expression of the target polynucleotide in the presence of varying
amounts of the compound and in the absence of the compound.
28. A method of assessing toxicity of a test compound, the method
comprising: a) treating a biological sample containing nucleic
acids with the test compound, b) hybridizing the nucleic acids of
the treated biological sample with a probe comprising at least 20
contiguous nucleotides of a polynucleotide of claim 11 under
conditions whereby a specific hybridization complex is formed
between said probe and a target polynucleotide in the biological
sample, said target polynucleotide comprising a polynucleotide
sequence of a polynucleotide of claim 11 or fragment thereof, c)
quantifying the amount of hybridization complex, and d) comparing
the amount of hybridization complex in the treated biological
sample with the amount of hybridization complex in an untreated
biological sample, wherein a difference in the amount of
hybridization complex in the treated biological sample is
indicative of toxicity of the test compound.
29. A diagnostic test for a condition or disease associated with
the expression of SDHH in a biological sample, the method
comprising: a) combining the biological sample with an antibody of
claim 10, under conditions suitable for the antibody to bind the
polypeptide and form an antibody:polypeptide complex, and b)
detecting the complex, wherein the presence of the complex
correlates with the presence of the polypeptide in the biological
sample.
30. The antibody of claim 10, wherein the antibody is: a) a
chimeric antibody, b) a single chain antibody, c) a Fab fragment,
d) a F(ab').sub.2 fragment, or e) a humanized antibody.
31. A composition comprising an antibody of claim 10 and an
acceptable excipient.
32. A method of diagnosing a condition or disease associated with
the expression of SDHH in a subject, comprising administering to
said subject an effective amount of the composition of claim
31.
33. A composition of claim 31, wherein the antibody is labeled.
34. A method of diagnosing a condition or disease associated with
the expression of SDHH in a subject, comprising administering to
said subject an effective amount of the composition of claim
33.
35. A method of preparing a polyclonal antibody with the
specificity of the antibody of claim 10, the method comprising: a)
immunizing an animal with a polypeptide having an amino acid
sequence of SEQ ID NO:1, or an immunogenic fragment thereof, under
conditions to elicit an antibody response, b) isolating antibodies
from said animal, and c) screening the isolated antibodies with the
polypeptide, thereby identifying a polyclonal antibody which binds
specifically to a polypeptide having an amino acid sequence of SEQ
ID NO:1.
36. An antibody produced by a method of claim 35.
37. A composition comprising the antibody of claim 36 and a
suitable carrier.
38. A method of making a monoclonal antibody with the specificity
of the antibody of claim 10, the method comprising: a) immunizing
an animal with a polypeptide having an amino acid sequence of SEQ
ID NO:1, or an immunogenic fragment thereof, under conditions to
elicit an antibody response, b) isolating antibody producing cells
from the animal, c) fusing the antibody producing cells with
immortalized cells to form monoclonal antibody-producing hybridoma
cells, d) culturing the hybridoma cells, and e) isolating from the
culture monoclonal antibody which binds specifically to a
polypeptide having an amino acid sequence of SEQ ID NO:1.
39. A monoclonal antibody produced by a method of claim 38.
40. A composition comprising the antibody of claim 39 and a
suitable carrier.
41. The antibody of claim 10, wherein the antibody is produced by
screening a Fab expression library.
42. The antibody of claim 10, wherein the antibody is produced by
screening a recombinant immunoglobulin library.
43. A method of detecting a polypeptide having an amino acid
sequence of SEQ ID NO:1 in a sample, the method comprising: a)
incubating the antibody of claim 10 with a sample under conditions
to allow specific binding of the antibody and the polypeptide, and
b) detecting specific binding, wherein specific binding indicates
the presence of a polypeptide having an amino acid sequence of SEQ
ID NO:1 in the sample.
44. A method of purifying a polypeptide having an amino acid
sequence of SEQ ID NO:1 from a sample, the method comprising: a)
incubating the antibody of claim 10 with a sample under conditions
to allow specific binding of the antibody and the polypeptide, and
b) separating the antibody from the sample and obtaining the
purified polypeptide having an amino acid sequence of SEQ ID
NO:1.
45. A polypeptide of claim 1, comprising the amino acid sequence of
SEQ ID NO:1.
46. A polynucleotide of claim 11, comprising the polynucleotide
sequence of SEQ ID NO:2.
Description
[0001] This application is a divisional application of U.S.
application Ser. No. 09/088,435 filed on Jun. 1, 1998, entitled
SERINE DEHYDRATASE HOMOLOG, the contents all of which are hereby
incorporated by reference.
FIELD OF THE INVENTION
[0002] This invention relates to nucleic acid and amino acid
sequences of a serine dehydratase homolog and to the use of these
sequences in the diagnosis, treatment, and prevention of disorders
of metabolism and cancer.
BACKGROUND OF THE INVENTION
[0003] Serine dehydratase (SDH) is an enzyme involved in
gluconeogenesis, the formation of glucose, the primary fuel for
cellular processes, from amino acids and certain types of fat.
Gluconeogenesis usually occurs in response to a decrease in supply,
or increase in demand, for glucose. SDH converts serine to pyruvate
and NH.sub.4.sup.+, following a dehydration step. SDH competes with
serine hydroxymethyltransferase and serine aminotransferase for
available serine. (Snell et al. (1988) Br. J. Cancer 57:87-90.) SDH
also catalyzes the deamination of L-threonine, preferring
L-threonine at higher pH values and L-serine at lower pH values.
(Pagani et al. 1989, Boll. Soc. Ital. Biol. Sper. 65: 625-629.) A
variety of SDHs have been observed in organisms ranging from
bacteria to vertebrates. A motif which interacts with SDH's
pyridoxal 5'-phosphate cofactor in several B6 enzymes is considered
characteristic of SDH. (Noda et al. 1988, FEBS Lett.
234:331-335)
[0004] SDH is synthesized primarily in the liver. (Su et al. 1992,
Gene 120:301-306.) In rats, which are nocturnal feeders, SDH
exhibits a circadian rhythm, reaching a maximum at the onset of
darkness and a minimum at the onset of light. (Ogawa et al. 1995,
Histochem. J. 27:380-387.) Variation in SDH levels appears to be
generated at the level of transcription. (Ogawa et al. 1994, Arch.
Biochem. Biophys. 308:285-291.) Cis-acting DNA elements required
for liver-specific expression of the SDH gene have been identified.
Expression of SDH mRNA in cultured hepatocytes appears to be
regulated in G0/G1 transition before entry into the S phase of the
cell cycle. (Noda et al., 1990, Biochem. Biophys. Res. Commun.
168:335-342.)
[0005] Gluconeogenesis is regulated by a variety of hormones
responsive to such factors as age, diet, and stress. Acute hormonal
regulation of liver carbohydrate metabolism mainly involves changes
in cytosolic levels of cyclic adenosine monophosphate (cAMP) and
Ca.sup.++ (Exton, 1987, Diabetes Metab. Rev. 3:163-183).
Epinephrine and glucagon both stimulate gluconeogenesis by
activating adenylate cyclase in the liver plasma membrane resulting
in accumulation of cAMP. cAMP up-regulates SDH transcription.
[0006] Induction of translatable mRNA for SDH in primary cultured
rat hepatocytes requires both dexamethasone and glucagon or cAMP, a
unique hormone requirement. Insulin and catecholamine are
antagonists of SDH induction (Ichihara et al. 1982, Mol. Cell
Biochem. 43:145-160.) These effects are mediated by the alpha-1
adrenergic signal transfer system. The dexamethasone induction is
age-dependent, apparently in correlation to the degree of
methylation of the promoter region of the gene. (Bohme et al.,
1987, Adv. Enzyme Regul. 26:31-61.) SDH transcription is induced in
rats near birth, when their diet changes from a continuous supply
of glucose via placental blood to relatively fat-rich
carbohydrate-poor blood. (Bohme et al 1983 Experientia
39:473-483.)
[0007] A number of conditions and disorders involve SDH, including
metabolic disorders and cancer. Gluconeogenesis from amino acids is
enhanced after acute renal failure. Nephrectomized rats show
significantly elevated SDH activity. Serine may play a special role
as a substrate for gluconeogenesis in acute uremic rats, probably
mediated by an activation of SDH. (Frohlich et al., 1977, Eur. J.
Clin. Invest. 7:261-268.) Attempts have been made to develop
procedures for estimation of SDH activity in blood serum to aid in
detection of a variety of liver tissue impairments. (Muzhichenko et
al. 1981, Vopr. Med. Khim 27:408-412.) Obese Zucker rats show
significantly depressed hepatic SDH activity, and the activity does
not increase in response to starvation as in lean rats. (Domenech
et al. 1993, Cell. Mol. Biol. (Noisy-le-grand) 39:405-414.) SDH
mRNA levels are markedly increased in streptozotocin-induced
diabetes. (Ogawa, supra.) Neonatal insulin resistance which
contributes to neonatal hyperglycemia has been linked to
epinephrine counteracting insulin's ability to decrease SDH gene
transcription. (Feng et al., 1996, Biochem. Mol. Med.
57:91-96.)
[0008] The balance of SDH, serine hydroxymethyltransferase and
serine aminotransferase activities is altered in human colon
carcinoma and rat sarcoma. SDH and serine aminotransferase
activities are absent in human colon carcinoma and rat sarcoma,
while the activity of serine hydroxymethyltransferase is markedly
increased. This change may be symptomatic of the biochemical
commitment to cellular replication in cancer cells. (Snell et al.,
supra.)
[0009] The discovery of a new serine dehydratase homolog and the
polynucleotides encoding it satisfies a need in the art by
providing new compositions which are useful in the diagnosis,
treatment, and prevention of disorders of metabolism and
cancer.
SUMMARY OF THE INVENTION
[0010] The invention is based on the discovery of a new human
serine dehydratase homolog (SDHH), the polynucleotides encoding
SDHH, and the use of these compositions for the diagnosis,
treatment, or prevention of disorders of metabolism and cancer.
[0011] The invention features a substantially purified polypeptide
comprising the amino acid sequence of SEQ ID NO: 1 or a fragment of
SEQ ID NO: 1.
[0012] The invention further provides a substantially purified
variant having at least 90% amino acid sequence identity to the
amino acid sequence of SEQ ID NO: 1 or a fragment of SEQ ID NO: 1.
The invention also provides an isolated and purified polynucleotide
encoding the polypeptide comprising the sequence of SEQ ID NO: 1 or
a fragment of SEQ ID NO: 1. The invention also includes an isolated
and purified polynucleotide variant having at least 90%
polynucleotide sequence identity to the polynucleotide encoding the
polypeptide comprising the amino acid sequence of SEQ ID NO: 1 or a
fragment of SEQ ID NO: 1.
[0013] The invention further provides an isolated and purified
polynucleotide which hybridizes under stringent conditions to the
polynucleotide encoding the polypeptide comprising the amino acid
sequence of SEQ ID NO: 1 or a fragment of SEQ ID NO: 1, as well as
an isolated and purified polynucleotide which is complementary to
the polynucleotide encoding the polypeptide comprising the amino
acid sequence of SEQ ID NO: 1 or a fragment of SEQ ID NO: 1.
[0014] The invention also provides an isolated and purified
polynucleotide comprising the polynucleotide sequence of SEQ ID
NO:2 or a fragment of SEQ ID NO:2, and an isolated and purified
polynucleotide variant having at least 90% polynucleotide sequence
identity to the polynucleotide comprising the polynucleotide
sequence of SEQ ID NO:2 or a fragment of SEQ ID NO:2. The invention
also provides an isolated and purified polynucleotide having a
sequence complementary to the polynucleotide comprising the
polynucleotide sequence of SEQ ID NO:2 or a fragment of SEQ ID
NO:2.
[0015] The invention further provides an expression vector
comprising at least a fragment of the polynucleotide encoding the
polypeptide comprising the sequence of SEQ ID NO:1 or a fragment of
SEQ ID NO:1. In another aspect, the expression vector is contained
within a host cell.
[0016] The invention also provides a method for producing a
polypeptide comprising the amino acid sequence of SEQ ID NO:1 or a
fragment of SEQ ID NO:1, the method comprising the steps of: (a)
culturing the host cell comprising an expression vector containing
at least a fragment of a polynucleotide encoding the polypeptide
comprising the amino acid sequence of SEQ ID NO:1 or a fragment of
SEQ ID NO: 1 under conditions suitable for the expression of the
polypeptide; and (b) recovering the polypeptide from the host cell
culture.
[0017] The invention also provides a pharmaceutical composition
comprising a substantially purified polypeptide having the sequence
of SEQ ID NO:1 or a fragment of SEQ ID NO:1 in conjunction with a
suitable pharmaceutical carrier.
[0018] The invention further includes a purified antibody which
binds to a polypeptide comprising the sequence of SEQ ID NO:1 or a
fragment of SEQ ID NO:1, as well as a purified agonist and a
purified antagonist of the polypeptide.
[0019] The invention also provides a method for treating or
preventing a disorder of metabolism associated with decreased
expression of SDHH, the method comprising administering to a
subject in need of such treatment an effective amount of a
pharmaceutical composition comprising substantially purified
polypeptide having the amino acid sequence of SEQ ID NO:1 or a
fragment of SEQ ID NO:1.
[0020] The invention also provides a method for treating or
preventing a disorder of metabolism associated with increased
expression of SDHH, the method comprising administering to a
subject in need of such treatment an effective amount of an
antagonist of the polypeptide having the amino acid sequence of SEQ
ID NO:1 or a fragment of SEQ ID NO:1.
[0021] The invention also provides a method for treating or
preventing a cancer, the method comprising administering to a
subject in need of such treatment an effective amount of a
pharmaceutical composition comprising substantially purified
polypeptide having the amino acid sequence of SEQ ID NO:1 or a
fragment of SEQ ID NO:1.
[0022] The invention also provides a method for detecting a
polynucleotide encoding a polypeptide comprising the amino acid
sequence of SEQ ID NO: 1 or a fragment of SEQ ID NO: 1 in a
biological sample containing nucleic acids, the method comprising
the steps of: (a) hybridizing the complement of the polynucleotide
encoding the polypeptide comprising the amino acid sequence of SEQ
ID NO:1 or a fragment of SEQ ID NO:1 to at least one of the nucleic
acids of the biological sample, thereby forming a hybridization
complex; and (b) detecting the hybridization complex, wherein the
presence of the hybridization complex correlates with the presence
of a polynucleotide encoding the polypeptide comprising the amino
acid sequence of SEQ ID NO:1 or a fragment of SEQ ID NO:1 in the
biological sample. In one aspect, the nucleic acids of the
biological sample are amplified by the polymerase chain reaction
prior to the hybridizing step.
DESCRIPTION OF THE INVENTION
[0023] Before the present proteins, nucleotide sequences, and
methods are described, it is understood that this invention is not
limited to the particular methodology, protocols, cell lines,
vectors, and reagents described, as these may vary. It is also to
be understood that the terminology used herein is for the purpose
of describing particular embodiments only, and is not intended to
limit the scope of the present invention which will be limited only
by the appended claims.
[0024] It must be noted that as used herein and in the appended
claims, the singular forms "a," "an," and "the" include plural
reference unless the context clearly dictates otherwise. Thus, for
example, a reference to "a host cell" includes a plurality of such
host cells, and a reference to "an antibody" is a reference to one
or more antibodies and equivalents thereof known to those skilled
in the art, and so forth.
[0025] Unless defined otherwise, all technical and scientific terms
used herein have the same meanings as commonly understood by one of
ordinary skill in the art to which this invention belongs. Although
any methods and materials similar or equivalent to those described
herein can be used in the practice or testing of the present
invention, the preferred methods, devices, and materials are now
described. All publications mentioned herein are cited for the
purpose of describing and disclosing the cell lines, vectors, and
methodologies which are reported in the publications and which
might be used in connection with the invention. Nothing herein is
to be construed as an admission that the invention is not entitled
to antedate such disclosure by virtue of prior invention.
[0026] Definitions
[0027] "SDHH," as used herein, refers to the amino acid sequences
of substantially purified SDHH obtained from any species,
particularly a mammalian species, including bovine, ovine, porcine,
murine, equine, and preferably the human species, from any source,
whether natural, synthetic, semi-synthetic, or recombinant.
[0028] The term "agonist," as used herein, refers to a molecule
which, when bound to SDHH, increases or prolongs the duration of
the effect of SDHH. Agonists may include proteins, nucleic acids,
carbohydrates, or any other molecules which bind to and modulate
the effect of SDHH.
[0029] An "allelic variant," as this term is used herein, is an
alternative form of the gene encoding SDHH. Allelic variants may
result from at least one mutation in the nucleic acid sequence and
may result in altered mRNAs or in polypeptides whose structure or
function may or may not be altered. Any given natural or
recombinant gene may have none, one, or many allelic forms. Common
mutational changes which give rise to allelic variants are
generally ascribed to natural deletions, additions, or
substitutions of nucleotides. Each of these types of changes may
occur alone, or in combination with the others, one or more times
in a given sequence.
[0030] "Altered" nucleic acid sequences encoding SDHH, as described
herein, include those sequences with deletions, insertions, or
substitutions of different nucleotides, resulting in a
polynucleotide the same as SDHH or a polypeptide with at least one
functional characteristic of SDHH. Included within this definition
are polymorphisms which may or may not be readily detectable using
a particular oligonucleotide probe of the polynucleotide encoding
SDHH, and improper or unexpected hybridization to allelic variants,
with a locus other than the normal chromosomal locus for the
polynucleotide sequence encoding SDHH. The encoded protein may also
be "altered," and may contain deletions, insertions, or
substitutions of amino acid residues which produce a silent change
and result in a functionally equivalent SDHH. Deliberate amino acid
substitutions may be made on the basis of similarity in polarity,
charge, solubility, hydrophobicity, hydrophilicity, and/or the
amphipathic nature of the residues, as long as the biological or
immunological activity of SDHH is retained. For example, negatively
charged amino acids may include aspartic acid and glutamic acid,
positively charged amino acids may include lysine and arginine, and
amino acids with uncharged polar head groups having similar
hydrophilicity values may include leucine, isoleucine, and valine;
glycine and alanine; asparagine and glutamine; serine and
threonine; and phenylalanine and tyrosine.
[0031] The terms "amino acid" or "amino acid sequence," as used
herein, refer to an oligopeptide, peptide, polypeptide, or protein
sequence, or a fragment of any of these, and to naturally occurring
or synthetic molecules. In this context, "fragments," "immunogenic
fragments," or "antigenic fragments" refer to fragments of SDHH
which are preferably about 5 to about 15 amino acids in length,
most preferably 14 amino acids, and which retain some biological
activity or immunological activity of SDHH. Where "amino acid
sequence" is recited herein to refer to an amino acid sequence of a
naturally occurring protein molecule, "amino acid sequence" and
like terms are not meant to limit the amino acid sequence to the
complete native amino acid sequence associated with the recited
protein molecule.
[0032] "Amplification," as used herein, relates to the production
of additional copies of a nucleic acid sequence. Amplification is
generally carried out using polymerase chain reaction (PCR)
technologies well known in the art. (See, e.g., Dieffenbach, C. W.
and G. S. Dveksler (1995) PCR Primer, a Laboratory Manual, Cold
Spring Harbor Press, Plainview, N.Y., pp.1-5.)
[0033] The term "antagonist," as it is used herein, refers to a
molecule which, when bound to SDHH, decreases the amount or the
duration of the effect of the biological or immunological activity
of SDHH. Antagonists may include proteins, nucleic acids,
carbohydrates, antibodies, or any other molecules which decrease
the effect of SDHH.
[0034] As used herein, the term "antibody" refers to intact
molecules as well as to fragments thereof, such as Fab,
F(ab').sub.2, and Fv fragments, which are capable of binding the
epitopic determinant. Antibodies that bind SDHH polypeptides can be
prepared using intact polypeptides or using fragments containing
small peptides of interest as the immunizing antigen. The
polypeptide or oligopeptide used to immunize an animal (e.g., a
mouse, a rat, or a rabbit) can be derived from the translation of
RNA, or synthesized chemically, and can be conjugated to a carrier
protein if desired. Commonly used carriers that are chemically
coupled to peptides include bovine serum albumin, thyroglobulin,
and keyhole limpet hemocyanin (KLH). The coupled peptide is then
used to immunize the animal.
[0035] The term "antigenic determinant," as used herein, refers to
that fragment of a molecule (i.e., an epitope) that makes contact
with a particular antibody. When a protein or a fragment of a
protein is used to immunize a host animal, numerous regions of the
protein may induce the production of antibodies which bind
specifically to antigenic determinants (given regions or
three-dimensional structures on the protein). An antigenic
determinant may compete with the intact antigen (i.e., the
immunogen used to elicit the immune response) for binding to an
antibody.
[0036] The term "antisense," as used herein, refers to any
composition containing a nucleic acid sequence which is
complementary to the "sense" strand of a specific nucleic acid
sequence. Antisense molecules may be produced by any method
including synthesis or transcription. Once introduced into a cell,
the complementary nucleotides combine with natural sequences
produced by the cell to form duplexes and to block either
transcription or translation. The designation "negative" can refer
to the antisense strand, and the designation "positive" can refer
to the sense strand.
[0037] As used herein, the term "biologically active," refers to a
protein having structural, regulatory, or biochemical functions of
a naturally occurring molecule. Likewise, "immunologically active"
refers to the capability of the natural, recombinant, or synthetic
SDHH, or of any oligopeptide thereof, to induce a specific immune
response in appropriate animals or cells and to bind with specific
antibodies.
[0038] The terms "complementary" or "complementarity," as used
herein, refer to the natural binding of polynucleotides under
permissive salt and temperature conditions by base pairing. For
example, the sequence "A-G-T" binds to the complementary sequence
"T-C-A." Complementarity between two single-stranded molecules may
be "partial," such that only some of the nucleic acids bind, or it
may be "complete," such that total complementarity exists between
the single stranded molecules. The degree of complementarity
between nucleic acid strands has significant effects on the
efficiency and strength of the hybridization between the nucleic
acid strands. This is of particular importance in amplification
reactions, which depend upon binding between nucleic acids strands,
and in the design and use of peptide nucleic acid (PNA)
molecules.
[0039] A "composition comprising a given polynucleotide sequence"
or a "composition comprising a given amino acid sequence," as these
terms are used herein, refer broadly to any composition containing
the given polynucleotide or amino acid sequence. The composition
may comprise a dry formulation, an aqueous solution, or a sterile
composition. Compositions comprising polynucleotide sequences
encoding SDHH or fragments of SDHH may be employed as hybridization
probes. The probes may be stored in freeze-dried form and may be
associated with a stabilizing agent such as a carbohydrate. In
hybridizations, the probe may be deployed in an aqueous solution
containing salts, e.g., NaCl, detergents, e.g.,sodium dodecyl
sulfate (SDS), and other components, e.g., Denhardt's solution, dry
milk, salmon sperm DNA, etc.
[0040] "Consensus sequence," as used herein, refers to a nucleic
acid sequence which has been resequenced to resolve uncalled bases,
extended using XL-PCR (Perkin Elmer, Norwalk, Conn.) in the 5'
and/or the 3' direction, and resequenced, or which has been
assembled from the overlapping sequences of more than one Incyte
Clone using a computer program for fragment assembly, such as the
GELVIEW fragment assembly system (GCG, Madison, Wis.). Some
sequences have been both extended and assembled to produce the
consensus sequence.
[0041] As used herein, the term "correlates with expression of a
polynucleotide" indicates that the detection of the presence of
nucleic acids, the same or related to a nucleic acid sequence
encoding SDHH, by Northern analysis is indicative of the presence
of nucleic acids encoding SDHH in a sample, and thereby correlates
with expression of the transcript from the polynucleotide encoding
SDHH.
[0042] A "deletion," as the term is used herein, refers to a change
in the amino acid or nucleotide sequence that results in the
absence of one or more amino acid residues or nucleotides.
[0043] The term "derivative," as used herein, refers to the
chemical modification of a polypeptide sequence, or a
polynucleotide sequence. Chemical modifications of a polynucleotide
sequence can include, for example, replacement of hydrogen by an
alkyl, acyl, or amino group. A derivative polynucleotide encodes a
polypeptide which retains at least one biological or immunological
function of the natural molecule. A derivative polypeptide is one
modified by glycosylation, pegylation, or any similar process that
retains at least one biological or immunological function of the
polypeptide from which it was derived.
[0044] The term "similarity," as used herein, refers to a degree of
complementarity. There may be partial similarity or complete
similarity. The word "identity" may substitute for the word
"similarity." A partially complementary sequence that at least
partially inhibits an identical sequence from hybridizing to a
target nucleic acid is referred to as "substantially similar." The
inhibition of hybridization of the completely complementary
sequence to the target sequence may be examined using a
hybridization assay (Southern or Northern blot, solution
hybridization, and the like) under conditions of reduced
stringency. A substantially similar sequence or hybridization probe
will compete for and inhibit the binding of a completely similar
(identical) sequence to the target sequence under conditions of
reduced stringency. This is not to say that conditions of reduced
stringency are such that non-specific binding is permitted, as
reduced stringency conditions require that the binding of two
sequences to one another be a specific (i.e., a selective)
interaction. The absence of non-specific binding may be tested by
the use of a second target sequence which lacks even a partial
degree of complementarity (e.g., less than about 30% similarity or
identity). In the absence of non-specific binding, the
substantially similar sequence or probe will not hybridize to the
second non-complementary target sequence.
[0045] The phrases "percent identity" or "% identity" refer to the
percentage of sequence similarity found in a comparison of two or
more amino acid or nucleic acid sequences. Percent identity can be
determined electronically, e.g., by using the MEGALIGN program
(DNASTAR, Inc., Madison Wis.). The MEGALIGN program can create
alignments between two or more sequences according to different
methods, e.g., the clustal method. (See, e.g., Higgins, D. G. and
P. M. Sharp (1988) Gene 73:237-244.) The clustal algorithm groups
sequences into clusters by examining the distances between all
pairs. The clusters are aligned pairwise and then in groups. The
percentage similarity between two amino acid sequences, e.g.,
sequence A and sequence B, is calculated by dividing the length of
sequence A, minus the number of gap residues in sequence A, minus
the number of gap residues in sequence B, into the sum of the
residue matches between sequence A and sequence B, times one
hundred. Gaps of low or of no similarity between the two amino acid
sequences are not included in determining percentage similarity.
Percent identity between nucleic acid sequences can also be counted
or calculated by other methods known in the art, e.g., the Jotun
Hein method. (See, e.g., Hein, J. (1990) Methods Enzymol.
183:626-645.) Identity between sequences can also be determined by
other methods known in the art, e.g., by varying hybridization
conditions.
[0046] "Human artificial chromosomes" (HACs), as described herein,
are linear microchromosomes which may contain DNA sequences of
about 6 kb to 10 Mb in size, and which contain all of the elements
required for stable mitotic chromosome segregation and maintenance.
(See, e.g., Harrington, J. J. et al. (1997) Nat Genet.
15:345-355.)
[0047] The term "humanized antibody," as used herein, refers to
antibody molecules in which the amino acid sequence in the
non-antigen binding regions has been altered so that the antibody
more closely resembles a human antibody, and still retains its
original binding ability.
[0048] "Hybridization," as the term is used herein, refers to any
process by which a strand of nucleic acid binds with a
complementary strand through base pairing.
[0049] As used herein, the term "hybridization complex" refers to a
complex formed between two nucleic acid sequences by virtue of the
formation of hydrogen bonds between complementary bases. A
hybridization complex may be formed in solution (e.g., C.sub.0t or
R.sub.0t analysis) or formed between one nucleic acid sequence
present in solution and another nucleic acid sequence immobilized
on a solid support (e.g., paper, membranes, filters, chips, pins or
glass slides, or any other appropriate substrate to which cells or
their nucleic acids have been fixed).
[0050] The words "insertion" or "addition," as used herein, refer
to changes in an amino acid or nucleotide sequence resulting in the
addition of one or more amino acid residues or nucleotides,
respectively, to the sequence found in the naturally occurring
molecule.
[0051] "Immune response" can refer to conditions associated with
inflammation, trauma, immune disorders, or infectious or genetic
disease, etc. These conditions can be characterized by expression
of various factors, e.g., cytokines, chemokines, and other
signaling molecules, which may affect cellular and systemic defense
systems.
[0052] The term "microarray," as used herein, refers to an
arrangement of distinct polynucleotides arrayed on a substrate,
e.g., paper, nylon or any other type of membrane, filter, chip,
glass slide, or any other suitable solid support.
[0053] The terms "element" or "array element" as used herein in a
microarray context, refer to hybridizable polynucleotides arranged
on the surface of a substrate.
[0054] The term "modulate," as it appears herein, refers to a
change in the activity of SDHH. For example, modulation may cause
an increase or a decrease in protein activity, binding
characteristics, or any other biological, functional, or
immunological properties of SDHH.
[0055] The phrases "nucleic acid" or "nucleic acid sequence," as
used herein, refer to a nucleotide, oligonucleotide,
polynucleotide, or any fragment thereof. These phrases also refer
to DNA or RNA of genomic or synthetic origin which may be
single-stranded or double-stranded and may represent the sense or
the antisense strand, to peptide nucleic acid (PNA), or to any
DNA-like or RNA-like material. In this context, "fragments" refers
to those nucleic acid sequences which, when translated, would
produce polypeptides retaining some functional characteristic,
e.g., antigenicity, or structural domain characteristic, e.g.,
ATP-binding site, of the full-length polypeptide.
[0056] The terms "operably associated" or "operably linked," as
used herein, refer to functionally related nucleic acid sequences.
A promoter is operably associated or operably linked with a coding
sequence if the promoter controls the translation of the encoded
polypeptide. While operably associated or operably linked nucleic
acid sequences can be contiguous and in the same reading frame,
certain genetic elements, e.g., repressor genes, are not
contiguously linked to the sequence encoding the polypeptide but
still bind to operator sequences that control expression of the
polypeptide.
[0057] The term "oligonucleotide," as used herein, refers to a
nucleic acid sequence of at least about 6 nucleotides to 60
nucleotides, preferably about 15 to 30 nucleotides, and most
preferably about 20 to 25 nucleotides, which can be used in PCR
amplification or in a hybridization assay or microarray. As used
herein, the term "oligonucleotide" is substantially equivalent to
the terms "amplimer," "primer," "oligomer," and "probe," as these
terms are commonly defined in the art.
[0058] "Peptide nucleic acid" (PNA), as used herein, refers to an
antisense molecule or anti-gene agent which comprises an
oligonucleotide of at least about 5 nucleotides in length linked to
a peptide backbone of amino acid residues ending in lysine. The
terminal lysine confers solubility to the composition. PNAs
preferentially bind complementary single stranded DNA or RNA and
stop transcript elongation, and may be pegylated to extend their
lifespan in the cell. (See, e.g., Nielsen, P. E. et al. (1993)
Anticancer Drug Des. 8:53-63.)
[0059] The term "sample," as used herein, is used in its broadest
sense. A biological sample suspected of containing nucleic acids
encoding SDHH, or fragments thereof, or SDHH itself, may comprise a
bodily fluid; an extract from a cell, chromosome, organelle, or
membrane isolated from a cell; a cell; genomic DNA, RNA, or cDNA,
in solution or bound to a solid support; a tissue; a tissue print;
etc.
[0060] As used herein, the terms "specific binding" or
"specifically binding" refer to that interaction between a protein
or peptide and an agonist, an antibody, or an antagonist. The
interaction is dependent upon the presence of a particular
structure of the protein, e.g., the antigenic determinant or
epitope, recognized by the binding molecule. For example, if an
antibody is specific for epitope "A," the presence of a polypeptide
containing the epitope A, or the presence of free unlabeled A, in a
reaction containing free labeled A and the antibody will reduce the
amount of labeled A that binds to the antibody.
[0061] As used herein, the term "stringent conditions" refers to
conditions which permit hybridization between polynucleotides and
the claimed polynucleotides. Stringent conditions can be defined by
salt concentration, the concentration of organic solvent (e.g.,
formamide), temperature, and other conditions well known in the
art. In particular, stringency can be increased by reducing the
concentration of salt, increasing the concentration of formamide,
or raising the hybridization temperature.
[0062] For example, stringent salt concentration will ordinarily be
less than about 750 mM NaCl and 75 mM trisodium citrate, preferably
less than about 500 mM NaCl and 50 mM trisodium citrate, and most
preferably less than about 250 mM NaCl and 25 mM trisodium citrate.
Low stringency hybridization can be obtained in the absence of
organic solvent, e.g., formamide, while high stringency
hybridization can be obtained in the presence of at least about 35%
formamide, and most preferably at least about 50% formamide.
Stringent temperature conditions will ordinarily include
temperatures of at least about 30.degree. C., more preferably of at
least about 37.degree. C., and most preferably of at least about
42.degree. C. Varying additional parameters, such as hybridization
time, the concentration of detergent, e.g., sodium dodecyl sulfate
(SDS), and the inclusion or exclusion of carrier DNA, are well
known to those skilled in the art. Various levels of stringency are
accomplished by combining these various conditions as needed. In a
preferred embodiment, hybridization will occur at 30.degree. C. in
750 mM NaCl, 75 mM trisodium citrate, and 1% SDS. In a more
preferred embodiment, hybridization will occur at 37.degree. C. in
500 mM NaCl, 50 mM trisodium citrate, 1% SDS, 35% formamide, and
100 .mu.g/ml denatured salmon sperm DNA (ssDNA). In a most
preferred embodiment, hybridization will occur at 42.degree. C. in
250 mM NaCl, 25 mM trisodium citrate, 1% SDS, 50% formamide, and
200 .mu.g/ml ssDNA. Useful variations on these conditions will be
readily apparent to those skilled in the art.
[0063] The washing steps which follow hybridization can also vary
in stringency. Wash stringency conditions can be defined by salt
concentration and by temperature. As above, wash stringency can be
increased by decreasing salt concentration or by increasing
temperature. For example, stringent salt concentration for the wash
steps will preferably be less than about 30 mM NaCl and 3 mM
trisodium citrate, and most preferably less than about 15 mM NaCl
and 1.5 mM trisodium citrate. Stringent temperature conditions for
the wash steps will ordinarily include temperature of at least
about 25.degree. C., more preferably of at least about 42.degree.
C., and most preferably of at least about 68.degree. C. In a
preferred embodiment, wash steps will occur at 25.degree. C. in 30
mM NaCl, 3 mM trisodium citrate, and 0.1% SDS. In a more preferred
embodiment, wash steps will occur at 42.degree. C. in 15 mM NaCl,
1.5 mM trisodium citrate, and 0.1% SDS. In a most preferred
embodiment, wash steps will occur at 68.degree. C. in 15 mM NaCl,
1.5 mM trisodium citrate, and 0. 1% SDS. Additional variations on
these conditions will be readily apparent to those skilled in the
art.
[0064] The term "substantially purified," as used herein, refers to
nucleic acid or amino acid sequences that are removed from their
natural environment and are isolated or separated, and 10 are at
least about 60% free, preferably about 75% free, and most
preferably about 90% free from other components with which they are
naturally associated.
[0065] A "substitution," as used herein, refers to the replacement
of one or more amino acids or nucleotides by different amino acids
or nucleotides, respectively.
[0066] "Transformation," as defined herein, describes a process by
which exogenous DNA enters and changes a recipient cell.
Transformation may occur under natural or artificial conditions
according to various methods well known in the art, and may rely on
any known method for the insertion of foreign nucleic acid
sequences into a prokaryotic or eukaryotic host cell. The method
for transformation is selected based on the type of host cell being
transformed and may include, but is not limited to, viral
infection, electroporation, heat shock, lipofection, and particle
bombardment. The term "transformed" cells includes stably
transformed cells in which the inserted DNA is capable of
replication either as an autonomously replicating plasmid or as
part of the host chromosome, as well as transiently transformed
cells which express the inserted DNA or RNA for limited periods of
time.
[0067] A "variant" of SDHH, as used herein, refers to an amino acid
sequence that is altered by one or more amino acids. The variant
may have "conservative" changes, wherein a substituted amino acid
has similar structural or chemical properties (e.g., replacement of
leucine with isoleucine). More rarely, a variant may have
"nonconservative" changes (e.g., replacement of glycine with
tryptophan). Analogous minor variations may also include amino acid
deletions or insertions, or both. Guidance in determining which
amino acid residues may be substituted, inserted, or deleted
without abolishing biological or immunological activity may be
found using computer programs well known in the art, for example,
LASERGENE software.
[0068] The Invention
[0069] The invention is based on the discovery of a new human
serine dehydratase homolog (SDHH), the polynucleotides encoding
SDHH, and the use of these compositions for the diagnosis,
treatment, or prevention of disorders of metabolism and cancer.
[0070] Nucleic acids encoding the SDHH of the present invention
were first identified in Incyte Clone 2752518 from the THP-1
promonocyte cell cDNA library (THP1AZS08) using a computer search,
e.g., BLAST, for amino acid sequence alignments. A consensus
sequence, SEQ ID NO:2, was derived from the following overlapping
and/or extended nucleic acid sequences: Incyte Clones 638642
(BRSTNOT03), 823439 (KERANOT02) and 2752518 (THP1AZS08).
[0071] In one embodiment, the invention encompasses a polypeptide
comprising the amino acid sequence of SEQ ID NO:1. SDHH is 329
amino acids in length and has a potential casein kinase II
phosphorylation site at residue T218; and two potential protein
kinase C phosphorylation sites at residues S46 and T116. SDHH has
the serine/threonine dehydratase pyridoxal-phosphate attachment
site at E39. SDHH has chemical and structural similarity with rat
liver serine dehydratase (GI 57225), and human liver serine
dehydratase (GI 338030) In particular, SDHH and rat liver serine
dehydratase share 53.2% identity, and SDHH and human liver serine
dehydratase share 56.7% identity. A region of unique sequence in
SDHH from about amino acid 2 to about amino acid 8 is encoded by a
fragment of SEQ ID NO:2 from about nucleotide 300 to about
nucleotide 318. Northern analysis shows the expression of SDHH in
various libraries, 48% of which are cancerous, 29% are involved in
immune response, and 23% are fetal, cell line or proliferating, 22%
are from gastrointestinal tissue, 16% from immune tissue, 16% from
reproductive tissue, and 12% are from cardiovascular tissue.
[0072] The invention also encompasses SDHH variants. A preferred
SDHH variant is one which has at least about 80%, more preferably
at least about 90%, and most preferably at least about 95% amino
acid sequence identity to the SDHH amino acid sequence, and which
contains at least one functional or structural characteristic of
SDHH.
[0073] The invention also encompasses polynucleotides which encode
SDHH. In a particular embodiment, the invention encompasses a
polynucleotide sequence comprising the sequence of SEQ ID NO:2,
which encodes an SDHH.
[0074] The invention also encompasses a variant of a polynucleotide
sequence encoding SDHH. In particular, such a variant
polynucleotide sequence will have at least about 80%, more
preferably at least about 90%, and most preferably at least about
95% polynucleotide sequence identity to the polynucleotide sequence
encoding SDHH. A particular aspect of the invention encompasses a
variant of SEQ ID NO:2 which has at least about 80%, more
preferably at least about 90%, and most preferably at least about
95% polynucleotide sequence identity to SEQ ID NO:2. Any one of the
polynucleotide variants described above can encode an amino acid
sequence which contains at least one functional or structural
characteristic of SDHH.
[0075] It will be appreciated by those skilled in the art that as a
result of the degeneracy of the genetic code, a multitude of
polynucleotide sequences encoding SDHH, some bearing minimal
similarity to the polynucleotide sequences of any known and
naturally occurring gene, may be produced. Thus, the invention
contemplates each and every possible variation of polynucleotide
sequence that could be made by selecting combinations based on
possible codon choices. These combinations are made in accordance
with the standard triplet genetic code as applied to the
polynucleotide sequence of naturally occurring SDHH, and all such
variations are to be considered as being specifically
disclosed.
[0076] Although nucleotide sequences which encode SDHH and its
variants are preferably capable of hybridizing to the nucleotide
sequence of the naturally occurring SDHH under appropriately
selected conditions of stringency, it may be advantageous to
produce nucleotide sequences encoding SDHH or its derivatives
possessing a substantially different codon usage, e.g., inclusion
of non-naturally occurring codons. Codons may be selected to
increase the rate at which expression of the peptide occurs in a
particular prokaryotic or eukaryotic host in accordance with the
frequency with which particular codons are utilized by the host.
Other reasons for substantially altering the nucleotide sequence
encoding SDHH and its derivatives without altering the encoded
amino acid sequences include the production of RNA transcripts
having more desirable properties, such as a greater half-life, than
transcripts produced from the naturally occurring sequence.
[0077] The invention also encompasses production of DNA sequences
which encode SDHH and SDHH derivatives, or fragments thereof,
entirely by synthetic chemistry. After production, the synthetic
sequence may be inserted into any of the many available expression
vectors and cell systems using reagents well known in the art.
Moreover, synthetic chemistry may be used to introduce mutations
into a sequence encoding SDHH or any fragment thereof.
[0078] Also encompassed by the invention are polynucleotide
sequences that are capable of hybridizing to the claimed
polynucleotide sequences, and, in particular, to those shown in SEQ
ID NO:2, or a fragment of SEQ ID NO:2, under various conditions of
stringency. (See, e.g., Wahl, G. M. and S. L. Berger (1987) Methods
Enzymol. 152:399-407; Kimmel, A. R. (1987) Methods Enzymol.
152:507-511.)
[0079] Methods for DNA sequencing are well known and generally
available in the art and may be used to practice any of the
embodiments of the invention. The methods may employ such enzymes
as the Klenow fragment of DNA polymerase I, SEQUENASE (US
Biochemical Corp., Cleveland, Ohio), Taq polymerase (Perkin Elmer),
thermostable T7 polymerase (Amersham, Chicago, Ill.), or
combinations of polymerases and proofreading exonucleases such as
those found in the ELONGASE amplification system (GIBCO BRL,
Gaithersburg, Md.). Preferably, the process is automated with
machines such as the MICROLAB 2200 liquid transfer system
(Hamilton, Reno, Nev.), Peltier PTC200 thermal cycler (MJ Research,
Watertown, Mass.) and the ABI CATALYST and 373 and 377 DNA
sequencers (Perkin Elmer).
[0080] The nucleic acid sequences encoding SDHH may be extended
utilizing a partial nucleotide sequence and employing various
PCR-based methods known in the art to detect upstream sequences,
such as promoters and regulatory elements. For example, one method
which may be employed, restriction-site PCR, uses universal and
nested primers to amplify unknown sequence from genomic DNA within
a cloning vector. (See, e.g., Sarkar, G. (1993) PCR Methods Applic.
2:318-322.) Another method, inverse PCR, uses primers that extend
in divergent directions to amplify unknown sequence from a
circularized template. The template is derived from restriction
fragments comprising a known genomic locus and surrounding
sequences. (See, e.g., Triglia, T. et al. (1988) Nucleic Acids Res.
16:8186.) A third method, capture PCR, involves PCR amplification
of DNA fragments adjacent to known sequences in human and yeast
artificial chromosome DNA. (See, e.g., Lagerstrom, M. et al. (1991)
PCR Methods Applic. 1:111-119.) In this method, multiple
restriction enzyme digestions and ligations may be used to insert
an engineered double-stranded sequence into a region of unknown
sequence before performing PCR. Other methods which may be used to
retrieve unknown sequences are known in the art. (See, e.g.,
Parker, J. D. et al. (1991) Nucleic Acids Res. 19:3055-306).
Additionally, one may use PCR, nested primers, and PROMOTERFINDER
libraries to walk genomic DNA (Clontech, Palo Alto, Calif.). This
procedure avoids the need to screen libraries and is useful in
finding intron/exon junctions. For all PCR-based methods, primers
may be designed using commercially available software, such as
OLIGO 4.06 primer analysis software (National Biosciences Inc.,
Plymouth, Minn.) or another appropriate program, to be about 22 to
30 nucleotides in length, to have a GC content of about 50% or
more, and to anneal to the template at temperatures of about
68.degree. C. to 72.degree. C.
[0081] When screening for full-length cDNAs, it is preferable to
use libraries that have been size-selected to include larger cDNAs.
In addition, random-primed libraries, which often include sequences
containing the 5' regions of genes, are preferable for situations
in which an oligo d(T) library does not yield a full-length cDNA.
Genomic libraries may be useful for extension of sequence into 5'
non-transcribed regulatory regions.
[0082] Capillary electrophoresis systems which are commercially
available may be used to analyze the size or confirm the nucleotide
sequence of sequencing or PCR products. In particular, capillary
sequencing may employ flowable polymers for electrophoretic
separation, four different nucleotide-specific, laser-stimulated
fluorescent dyes, and a charge coupled device camera for detection
of the emitted wavelengths. Output/light intensity may be converted
to electrical signal using appropriate software (e.g., GENOTYPER
and SEQUENCE NAVIGATOR, Perkin Elmer), and the entire process from
loading of samples to computer analysis and electronic data display
may be computer controlled. Capillary electrophoresis is especially
preferable for sequencing small DNA fragments which may be present
in limited amounts in a particular sample.
[0083] In another embodiment of the invention, polynucleotide
sequences or fragments thereof which encode SDHH may be cloned in
recombinant DNA molecules that direct expression of SDHH, or
fragments or functional equivalents thereof, in appropriate host
cells. Due to the inherent degeneracy of the genetic code, other
DNA sequences which encode substantially the same or a functionally
equivalent amino acid sequence may be produced and used to express
SDHH.
[0084] The nucleotide sequences of the present invention can be
engineered using methods generally known in the art in order to
alter SDHH-encoding sequences for a variety of purposes including,
but not limited to, modification of the cloning, processing, and/or
expression of the gene product. DNA shuffling by random
fragmentation and PCR reassembly of gene fragments and synthetic
oligonucleotides may be used to engineer the nucleotide sequences.
For example, oligonucleotide-mediated site-directed mutagenesis may
be used to introduce mutations that create new restriction sites,
alter glycosylation patterns, change codon preference, produce
splice variants, and so forth.
[0085] In another embodiment, sequences encoding SDHH may be
synthesized, in whole or in part, using chemical methods well known
in the art. (See, e.g., Caruthers, M. H. et al. (1980) Nucl. Acids
Res. Symp. Ser. 215-223, and Horn, T. et al. (1980) Nucl. Acids
Res. Symp. Ser. 225-232.) Alternatively, SDHH itself or a fragment
thereof may be synthesized using chemical methods. For example,
peptide synthesis can be performed using various solid-phase
techniques. (See, e.g., Roberge, J. Y. et al. (1995) Science
269:202-204.) Automated synthesis may be achieved using the ABI
431A peptide synthesizer (Perkin Elmer). Additionally, the amino
acid sequence of SDHH, or any part thereof, may be altered during
direct synthesis and/or combined with sequences from other
proteins, or any part thereof, to produce a variant
polypeptide.
[0086] The peptide may be substantially purified by preparative
high performance liquid chromatography. (See, e.g, Chiez, R. M. and
F. Z. Regnier (1990) Methods Enzymol. 182:392-421.) The composition
of the synthetic peptides may be confirmed by amino acid analysis
or by sequencing. (See, e.g., Creighton, T. (1984) Proteins,
Structures and Molecular Properties, WH Freeman and Co., New York,
N.Y.)
[0087] In order to express a biologically active SDHH, the
nucleotide sequences encoding SDHH or derivatives thereof may be
inserted into an appropriate expression vector, i.e., a vector
which contains the necessary elements for transcriptional and
translational control of the inserted coding sequence in a suitable
host. These elements include regulatory sequences, such as
enhancers, constitutive and inducible promoters, and 5' and 3'
untranslated regions in the vector and in polynucleotide sequences
encoding SDHH. Such elements may vary in their strength and
specificity. Specific initiation signals may also be used to
achieve more efficient translation of sequences encoding SDHH. Such
signals include the ATG initiation codon and adjacent sequences,
e.g. the Kozak sequence. In cases where sequences encoding SDHH and
its initiation codon and upstream regulatory sequences are inserted
into the appropriate expression vector, no additional
transcriptional or translational control signals may be needed.
However, in cases where only coding sequence, or a fragment
thereof, is inserted, exogenous translational control signals
including an in-frame ATG initiation codon should be provided by
the vector. Exogenous translational elements and initiation codons
may be of various origins, both natural and synthetic. The
efficiency of expression may be enhanced by the inclusion of
enhancers appropriate for the particular host cell system used.
(See, e.g., Scharf, D. et al. (1994) Results Probl. Cell Differ.
20:125-162.)
[0088] Methods which are well known to those skilled in the art may
be used to construct expression vectors containing sequences
encoding SDHH and appropriate transcriptional and translational
control elements. These methods include in vitro recombinant DNA
techniques, synthetic techniques, and in vivo genetic
recombination. (See, e.g., Sambrook, J. et al. (1989) Molecular
Cloning, A Laboratory Manual, Cold Spring Harbor Press, Plainview,
N.Y., ch. 4, 8, and 16-17; and Ausubel, F. M. et al. (1995, and
periodic supplements) Current Protocols in Molecular Biology, John
Wiley & Sons, New York, N.Y., ch. 9, 13, and 16.)
[0089] A variety of expression vector/host systems may be utilized
to contain and express sequences encoding SDHH. These include, but
are not limited to, microorganisms such as bacteria transformed
with recombinant bacteriophage, plasmid, or cosmid DNA expression
vectors; yeast transformed with yeast expression vectors; insect
cell systems infected with viral expression vectors (e.g.,
baculovirus); plant cell systems transformed with viral expression
vectors (e.g., cauliflower mosaic virus (CaMV) or tobacco mosaic
virus (TMV)) or with bacterial expression vectors (e.g., Ti or
pBR322 plasmids); or animal cell systems. The invention is not
limited by the host cell employed.
[0090] In bacterial systems, a number of cloning and expression
vectors may be selected depending upon the use intended for
polynucleotide sequences encoding SDHH. For example, routine
cloning, subcloning, and propagation of polynucleotide sequences
encoding SDHH can be achieved using a multifunctional E. coli
vector such as BLUESCRIPT (Stratagene) or PSPORT1 plasmid (GIBCO
BRL). Ligation of sequences encoding SDHH into the vector's
multiple cloning site disrupts the lacZ gene, allowing a
colorimetric screening procedure for identification of transformed
bacteria containing recombinant molecules. In addition, these
vectors may be useful for in vitro transcription, dideoxy
sequencing, single strand rescue with helper phage, and creation of
nested deletions in the cloned sequence. (See, e.g., Van Heeke, G.
and S. M. Schuster (1989) J. Biol. Chem. 264:5503-5509.) When large
quantities of SDHH are needed, e.g. for the production of
antibodies, vectors which direct high level expression of SDHH may
be used. For example, vectors containing the strong, inducible T5
or T7 bacteriophage promoter may be used.
[0091] Yeast expression systems may be used for production of SDHH.
A number of vectors containing constitutive or inducible promoters,
such as alpha factor, alcohol oxidase, and PGH, may be used in the
yeast Saccharomyces cerevisiae or Pichia pastoris. In addition,
such vectors direct either the secretion or intracellular retention
of expressed proteins and enable integration of foreign sequences
into the host genome for stable propagation. (See, e.g., Ausubel,
supra; and Grant et al. (1987) Methods Enzymol. 153:516-54; Scorer,
C. A. et al. (1994) Bio/Technology 12:181-184.)
[0092] Plant systems may also be used for expression of SDHH.
Transcription of sequences encoding SDHH may be driven viral
promoters, e.g., the 35S and 19S promoters of CaMV used alone or in
combination with the omega leader sequence from TMV. (Takamatsu, N.
(1987) EMBO J. 6:307-311.) Alternatively, plant promoters such as
the small subunit of RUBISCO or heat shock promoters may be used.
(See, e.g., Coruzzi, G. et al. (1984) EMBO J. 3:1671-1680; Broglie,
R. et al. (1984) Science 224:838-843; and Winter, J. et al. (1991)
Results Probl. Cell Differ. 17:85-105.) These constructs can be
introduced into plant cells by direct DNA transformation or
pathogen-mediated transfection. (See, e.g., Hobbs, S. or Murry, L.
E. in McGraw Hill Yearbook of Science and Technology (1992) McGraw
Hill, New York, N.Y.; pp. 191-196.)
[0093] In mammalian cells, a number of viral-based expression
systems may be utilized. In cases where an adenovirus is used as an
expression vector, sequences encoding SDHH may be ligated into an
adenovirus transcription/translation complex consisting of the late
promoter and tripartite leader sequence. Insertion in a
non-essential E1 or E3 region of the viral genome may be used to
obtain infective virus which expresses SDHH in host cells. (See,
e.g., Logan, J. and T. Shenk (1984) Proc. Natl. Acad. Sci.
81:3655-3659.) In addition, transcription enhancers, such as the
Rous sarcoma virus (RSV) enhancer, may be used to increase
expression in mammalian host cells. SV40 or EBV-based vectors may
also be used for high-level protein expression.
[0094] Human artificial chromosomes (HACs) may also be employed to
deliver larger fragments of DNA than can be contained in and
expressed from a plasmid. HACs of about 6 kb to 10 Mb are
constructed and delivered via conventional delivery methods
(liposomes, polycationic amino polymers, or vesicles) for
therapeutic purposes.
[0095] For long term production of recombinant proteins in
mammalian systems, stable expression of SDHH in cell lines is
preferred. For example, sequences encoding SDHH can be transformed
into cell lines using expression vectors which may contain viral
origins of replication and/or endogenous expression elements and a
selectable marker gene on the same or on a separate vector.
Following the introduction of the vector, cells may be allowed to
grow for about 1 to 2 days in enriched media before being switched
to selective media. The purpose of the selectable marker is to
confer resistance to a selective agent, and its presence allows
growth and recovery of cells which successfully express the
introduced sequences. Resistant clones of stably transformed cells
may be propagated using tissue culture techniques appropriate to
the cell type.
[0096] Any number of selection systems may be used to recover
transformed cell lines. These include, but are not limited to, the
herpes simplex virus thymidine kinase and adenine
phosphoribosyltransferase genes, for use in tk.sup.- or apr.sup.-
cells, respectively. (See, e.g., Wigler, M. et al. (1977) Cell
11:223-232; and Lowy, I. et al. (1980) Cell 22:817-823.) Also,
antimetabolite, antibiotic, or herbicide resistance can be used as
the basis for selection. For example, dhfr confers resistance to
methotrexate; neo confers resistance to the aminoglycosides
neomycin and G-418; and als or pat confer resistance to
chlorsulfuron and phosphinotricin acetyltransferase, respectively.
(See, e.g., Wigler, M. et al. (1980) Proc. Natl. Acad. Sci.
77:3567-3570; Colbere-Garapin, F. et al (1981) J. Mol. Biol.
150:1-14; and Murry, supra.) Additional selectable genes have been
described, e.g., trpB and hisD, which alter cellular requirements
for metabolites. (See, e.g., Hartman, S. C. and R. C. Mulligan
(1988) Proc. Natl. Acad. Sci. 85:8047-8051.) Visible markers, e.g.,
anthocyanins, green fluorescent proteins (GFP) (Clontech, Palo
Alto, Calif.), .beta. glucuronidase and its substrate
.beta.-D-glucuronoside, or luciferase and its substrate luciferin
may be used. These markers can be used not only to identify
transformants, but also to quantify the amount of transient or
stable protein expression attributable to a specific vector system.
(See, e.g., Rhodes, C. A. et al. (1995) Methods Mol. Biol.
55:121-131.)
[0097] Although the presence/absence of marker gene expression
suggests that the gene of interest is also present, the presence
and expression of the gene may need to be confirmed. For example,
if the sequence encoding SDHH is inserted within a marker gene
sequence, transformed cells containing sequences encoding SDHH can
be identified by the absence of marker gene function.
Alternatively, a marker gene can be placed in tandem with a
sequence encoding SDHH under the control of a single promoter.
Expression of the marker gene in response to induction or selection
usually indicates expression of the tandem gene as well.
[0098] In general, host cells that contain the nucleic acid
sequence encoding SDHH and that express SDHH may be identified by a
variety of procedures known to those of skill in the art. These
procedures include, but are not limited to, DNA-DNA or DNA-RNA
hybridizations, PCR amplification, and protein bioassay or
immunoassay techniques which include membrane, solution, or chip
based technologies for the detection and/or quantification of
nucleic acid or protein sequences.
[0099] Immunological methods for detecting and measuring the
expression of SDHH using either specific polyclonal or monoclonal
antibodies are known in the art. Examples of such techniques
include enzyme-linked immunosorbent assays (ELISAs),
radioimmunoassays (RIAs), and fluorescence activated cell sorting
(FACS). A two-site, monoclonal-based immunoassay utilizing
monoclonal antibodies reactive to two non-interfering epitopes on
SDHH is preferred, but a competitive binding assay may be employed.
These and other assays are well known in the art. (See, e.g.,
Hampton, R. et al. (1990) Serological Methods, a Laboratory Manual,
APS Press, St Paul, Minn., Section IV; Coligan, J. E. et al. (1997
and periodic supplements) Current Protocols in Immunology, Greene
Pub. Associates and Wiley-Interscience, New York, N.Y.; and Maddox,
D. E. et al. (1983) J. Exp. Med. 158:1211-1216).
[0100] A wide variety of labels and conjugation techniques are
known by those skilled in the art and may be used in various
nucleic acid and amino acid assays. Means for producing labeled
hybridization or PCR probes for detecting sequences related to
polynucleotides encoding SDHH include oligolabeling, nick
translation, end-labeling, or PCR amplification using a labeled
nucleotide. Alternatively, the sequences encoding SDHH, or any
fragments thereof, may be cloned into a vector for the production
of an mRNA probe. Such vectors are known in the art, are
commercially available, and may be used to synthesize RNA probes in
vitro by addition of an appropriate RNA polymerase such as T7, T3,
or SP6 and labeled nucleotides. These procedures may be conducted
using a variety of commercially available kits, such as those
provided by Pharmacia & Upjohn (Kalamazoo, Mich.), Promega
(Madison, Wis.), and U.S. Biochemical Corp. (Cleveland, Ohio).
Suitable reporter molecules or labels which may be used for ease of
detection include radionuclides, enzymes, fluorescent,
chemiluminescent, or chromogenic agents, as well as substrates,
cofactors, inhibitors, magnetic particles, and the like.
[0101] Host cells transformed with nucleotide sequences encoding
SDHH may be cultured under conditions suitable for the expression
and recovery of the protein from cell culture. The protein produced
by a transformed cell may be secreted or retained intracellularly
depending on the sequence and/or the vector used. As will be
understood by those of skill in the art, expression vectors
containing polynucleotides which encode SDHH may be designed to
contain signal sequences which direct secretion of SDHH through a
prokaryotic or eukaryotic cell membrane.
[0102] In addition, a host cell strain may be chosen for its
ability to modulate expression of the inserted sequences or to
process the expressed protein in the desired fashion. Such
modifications of the polypeptide include, but are not limited to,
acetylation, carboxylation, glycosylation, phosphorylation,
lipidation, and acylation. Post-translational processing which
cleaves a "prepro" form of the protein may also be used to specify
protein targeting, folding, and/or activity. Different host cells
which have specific cellular machinery and characteristic
mechanisms for post-translational activities (e.g., CHO, HeLa,
MDCK, HEK293, and W138), are available from the American Type
Culture Collection (ATCC, Manassas, Va.) and may be chosen to
ensure the correct modification and processing of the foreign
protein.
[0103] In another embodiment of the invention, natural, modified,
or recombinant nucleic acid sequences encoding SDHH may be ligated
to a heterologous sequence resulting in translation of a fusion
protein in any of the aforementioned host systems. For example, a
chimeric SDHH protein containing a heterologous moiety that can be
recognized by a commercially available antibody may facilitate the
screening of peptide libraries for inhibitors of SDHH activity.
Heterologous protein and peptide moieties may also facilitate
purification of fusion proteins using commercially available
affinity matrices. Such moieties include, but are not limited to,
glutathione S-transferase (GST), maltose binding protein (MBP),
thioredoxin (Trx), calmodulin binding peptide (CBP), 6-His, FLAG,
c-myc, and hemagglutinin (HA). GST, MBP, Trx, CBP, and 6-His enable
purification of their cognate fusion proteins on immobilized
glutathione, maltose, phenylarsine oxide, calmodulin, and
metal-chelate resins, respectively. FLAG, c-myc, and hemagglutinin
(HA) enable immunoaffinity purification of fusion proteins using
commercially available monoclonal and polyclonal antibodies that
specifically recognize these epitope tags. A fusion protein may
also be engineered to contain a proteolytic cleavage site located
between the SDHH encoding sequence and the heterologous protein
sequence, so that SDHH may be cleaved away from the heterologous
moiety following purification. Methods for fusion protein
expression and purification are discussed in Ausubel, F. M. et al.
(1995 and periodic supplements) Current Protocols in Molecular
Biology, John Wiley & Sons, New York, N.Y., ch 10. A variety of
commercially available kits may also be used to facilitate
expression and purification of fusion proteins.
[0104] In a further embodiment of the invention, synthesis of
radiolabeled SDHH may be achieved in vitro using the TNT rabbit
reticulocyte lysate or wheat germ extract systems (Promega,
Madison, Wis.). These systems couple transcription and translation
of protein-coding sequences operably associated with the T7, T3, or
SP6 promoters. Translation takes place in the presence of a
radiolabeled amino acid precursor, preferably
.sup.35S-methionine.
[0105] Fragments of SDHH may be produced not only by recombinant
production, but also by direct peptide synthesis using solid-phase
techniques. (See, e.g., Creighton, supra pp. 55-60.) Protein
synthesis may be performed by manual techniques or by automation.
Automated synthesis may be achieved, for example, using the APPLIED
BIOSYSTEMS 431A peptide synthesizer (Perkin Elmer). Various
fragments of SDHH may be synthesized separately and then combined
to produce the full length molecule.
[0106] Therapeutics
[0107] Chemical and structural similarity exists between SDHH and
rat liver serine dehydratase (GI 57225; SEQ ID NO:3), and human
liver serine dehydratase (GI 338030; SEQ ID NO:4) In addition, SDHH
is expressed in tissues which are cancerous, proliferating, or
involved in immune response. Therefore, SDHH appears to play a role
in disorders of metabolism and cancer.
[0108] In a disorder of metabolism which is associated with the
activation of disease processes by SDHH, it is beneficial to
decrease the expression of SDHH in a subject afflicted with the
disorder. In a disorder of metabolism which is associated with the
inhibition of SDHH, it is beneficial to provide the protein or
increase the expression of SDHH in a subject afflicted with the
disorder. Therefore, in one embodiment, SDHH or a fragment or
derivative thereof may be administered to a subject to treat or
prevent a disorder of metabolism. Such disorders can include, but
are not limited to, Addison's disease, cystic fibrosis, diabetes,
fatty hepatocirrhosis, galactosemia, goiter, hyperadrenalism,
hypoadrenalism, hyperparathyroidism, hypoparathyroidism,
hypercholesterolemia, hyperthyroidism, hypothyroidism
hyperlipidemia, hyperlipemia, lipid myopathies, obesity,
lipodystrophies, phenylketonuria, and renal failure.
[0109] In another embodiment, a vector capable of expressing SDHH
or a fragment or derivative thereof may be administered to a
subject to treat or prevent a disorder of metabolism including, but
not limited to, those described above.
[0110] In another embodiment, a pharmaceutical composition
comprising a substantially purified SDHH in conjunction with a
suitable pharmaceutical carrier may be administered to a subject to
treat or prevent a disorder of metabolism including, but not
limited to, those provided above.
[0111] In still another embodiment, an agonist which modulates the
activity of SDHH may be administered to a subject to treat or
prevent a disorder of metabolism including, but not limited to,
those listed above.
[0112] In a further embodiment, an antagonist of SDHH may be
administered to a subject to treat or prevent a disorder of
metabolism. Such a disorder of metabolism may include, but is not
limited to, those discussed above. In one aspect, an antibody which
specifically binds SDHH may be used directly as an antagonist or
indirectly as a targeting or delivery mechanism for bringing a
pharmaceutical agent to cells or tissue which express SDHH.
[0113] In an additional embodiment, a vector expressing the
complement of the polynucleotide encoding SDHH may be administered
to a subject to treat or prevent a disorder of metabolism
including, but not limited to, those described above.
[0114] In still another embodiment, SDHH or a fragment or
derivative thereof may be administered to a subject to treat or
prevent a cancer. Such disorders can include, but are not limited
to, adenocarcinoma, leukemia, lymphoma, melanoma, myeloma, sarcoma,
teratocarcinoma, and, in particular, cancers of the adrenal gland,
bladder, bone, bone marrow, brain, breast, cervix, gall bladder,
ganglia, gastrointestinal tract, heart, kidney, liver, lung,
muscle, ovary, pancreas, parathyroid, penis, prostate, salivary
glands, skin, spleen, testis, thymus, thyroid, and uterus.
[0115] In another embodiment, a vector capable of expressing SDHH
or a fragment or derivative thereof may be administered to a
subject to treat or prevent a cancer including, but not limited to,
those described above.
[0116] In a further embodiment, a pharmaceutical composition
comprising a substantially purified SDHH in conjunction with a
suitable pharmaceutical carrier may be administered to a subject to
treat or prevent a cancer including, but not limited to, those
provided above.
[0117] In still another embodiment, an agonist which modulates the
activity of SDHH may be administered to a subject to treat or
prevent a cancer including, but not limited to, those listed
above.
[0118] In other embodiments, any of the proteins, antagonists,
antibodies, agonists, complementary sequences, or vectors of the
invention may be administered in combination with other appropriate
therapeutic agents. Selection of the appropriate agents for use in
combination therapy may be made by one of ordinary skill in the
art, according to conventional pharmaceutical principles. The
combination of therapeutic agents may act synergistically to effect
the treatment or prevention of the various disorders described
above. Using this approach, one may be able to achieve therapeutic
efficacy with lower dosages of each agent, thus reducing the
potential for adverse side effects.
[0119] An antagonist of SDHH may be produced using methods which
are generally known in the art. In particular, purified SDHH may be
used to produce antibodies or to screen libraries of pharmaceutical
agents to identify those which specifically bind SDHH. Antibodies
to SDHH may also be generated using methods that are well known in
the art. Such antibodies may include, but are not limited to,
polyclonal, monoclonal, chimeric, and single chain antibodies, Fab
fragments, and fragments produced by a Fab expression library.
Neutralizing antibodies (i.e., those which inhibit dimer formation)
are especially preferred for therapeutic use.
[0120] For the production of antibodies, various hosts including
goats, rabbits, rats, mice, humans, and others may be immunized by
injection with SDHH or with any fragment or oligopeptide thereof
which has immunogenic properties. Depending on the host species,
various adjuvants may be used to increase immunological response.
Such adjuvants include, but are not limited to, Freund's, mineral
gels such as aluminum hydroxide, and surface active substances such
as lysolecithin, pluronic polyols, polyanions, peptides, oil
emulsions, KLH, and dinitrophenol. Among adjuvants used in humans,
BCG (bacilli Calmette-Guerin) and Corynebacterium parvum are
especially preferable.
[0121] It is preferred that the oligopeptides, peptides, or
fragments used to induce antibodies to SDHH have an amino acid
sequence consisting of at least about 5 amino acids, and, more
preferably, of at least about 10 amino acids. It is also preferable
that these oligopeptides, peptides, or fragments are identical to a
portion of the amino acid sequence of the natural protein and
contain the entire amino acid sequence of a small, naturally
occurring molecule. Short stretches of SDHH amino acids may be
fused with those of another protein, such as KLH, and antibodies to
the chimeric molecule may be produced.
[0122] Monoclonal antibodies to SDHH may be prepared using any
technique which provides for the production of antibody molecules
by continuous cell lines in culture. These include, but are not
limited to, the hybridoma technique, the human B-cell hybridoma
technique, and the EBV-hybridoma technique. (See, e.g., Kohler, G.
et al. (1975) Nature 256:495-497; Kozbor, D. et al. (1985) J.
Immunol. Methods 81:31-42; Cote, R. J. et al. (1983) Proc. Natl.
Acad. Sci. 80:2026-2030; and Cole, S. P. et al. (1984) Mol. Cell
Biol. 62:109-120.)
[0123] In addition, techniques developed for the production of
"chimeric antibodies," such as the splicing of mouse antibody genes
to human antibody genes to obtain a molecule with appropriate
antigen specificity and biological activity, can be used. (See,
e.g., Morrison, S. L. et al. (1984) Proc. Natl. Acad. Sci.
81:6851-6855; Neuberger, M. S. et al. (1984) Nature 312:604-608;
and Takeda, S. et al. (1985) Nature 314:452-454.) Alternatively,
techniques described for the production of single chain antibodies
may be adapted, using methods known in the art, to produce
SDHH-specific single chain antibodies. Antibodies with related
specificity, but of distinct idiotypic composition, may be
generated by chain shuffling from random combinatorial
immunoglobulin libraries. (See, e.g., Burton D. R. (1991) Proc.
Natl. Acad. Sci. 88:10134-10137.)
[0124] Antibodies may also be produced by inducing in vivo
production in the lymphocyte population or by screening
immunoglobulin libraries or panels of highly specific binding
reagents as disclosed in the literature. (See, e.g., Orlandi, R. et
al. (1989) Proc. Natl. Acad. Sci. 86: 3833-3837; and Winter, G. et
al. (1991) Nature 349:293-299.)
[0125] Antibody fragments which contain specific binding sites for
SDHH may also be generated. For example, such fragments include,
but are not limited to, F(ab')2 fragments produced by pepsin
digestion of the antibody molecule and Fab fragments generated by
reducing the disulfide bridges of the F(ab')2 fragments.
Alternatively, Fab expression libraries may be constructed to allow
rapid and easy identification of monoclonal Fab fragments with the
desired specificity. (See, e.g., Huse, W. D. et al. (1989) Science
246:1275-1281.)
[0126] Various immunoassays may be used for screening to identify
antibodies having the desired specificity. Numerous protocols for
competitive binding or immunoradiometric assays using either
polyclonal or monoclonal antibodies with established specificities
are well known in the art. Such immunoassays typically involve the
measurement of complex formation between SDHH and its specific
antibody. A two-site, monoclonal-based immunoassay utilizing
monoclonal antibodies reactive to two non-interfering SDHH epitopes
is preferred, but a competitive binding assay may also be employed.
(Maddox, supra.)
[0127] In another embodiment of the invention, the polynucleotides
encoding SDHH, or any fragment or complement thereof, may be used
for therapeutic purposes. In one aspect, the complement of the
polynucleotide encoding SDHH may be used in situations in which it
would be desirable to block the transcription of the mRNA. In
particular, cells may be transformed with sequences complementary
to polynucleotides encoding SDHH. Thus, complementary molecules or
fragments may be used to modulate SDHH activity, or to achieve
regulation of gene function. Such technology is now well known in
the art, and sense or antisense oligonucleotides or larger
fragments can be designed from various locations along the coding
or control regions of sequences encoding SDHH.
[0128] Expression vectors derived from retroviruses, adenoviruses,
or herpes or vaccinia viruses, or from various bacterial plasmids,
may be used for delivery of nucleotide sequences to the targeted
organ, tissue, or cell population. Methods which are well known to
those skilled in the art can be used to construct vectors to
express nucleic acid sequences complementary to the polynucleotides
encoding SDHH. (See, e.g., Sambrook, supra; and Ausubel,
supra.)
[0129] Genes encoding SDHH can be turned off by transforming a cell
or tissue with expression vectors which express high levels of a
polynucleotide, or fragment thereof, encoding SDHH. Such constructs
may be used to introduce untranslatable sense or antisense
sequences into a cell. Even in the absence of integration into the
DNA, such vectors may continue to transcribe RNA molecules until
they are disabled by endogenous nucleases. Transient expression may
last for a month or more with a non-replicating vector, and may
last even longer if appropriate replication elements are part of
the vector system.
[0130] As mentioned above, modifications of gene expression can be
obtained by designing complementary sequences or antisense
molecules (DNA, RNA, or PNA) to the control, 5', or regulatory
regions of the gene encoding SDHH. Oligonucleotides derived from
the transcription initiation site, e.g., between about positions
-10 and +10 from the start site, are preferred. Similarly,
inhibition can be achieved using triple helix base-pairing
methodology. Triple helix pairing is useful because it causes
inhibition of the ability of the double helix to open sufficiently
for the binding of polymerases, transcription factors, or
regulatory molecules. Recent therapeutic advances using triplex DNA
have been described in the literature. (See, e.g., Gee, J. E. et
al. (1994) in Huber, B. E. and B. I. Carr, Molecular and
Immunologic Approaches, Futura Publishing Co., Mt. Kisco, N.Y., pp.
163-177.) A complementary sequence or antisense molecule may also
be designed to block translation of mRNA by preventing the
transcript from binding to ribosomes.
[0131] Ribozymes, enzymatic RNA molecules, may also be used to
catalyze the specific cleavage of RNA. The mechanism of ribozyme
action involves sequence-specific hybridization of the ribozyme
molecule to complementary target RNA, followed by endonucleolytic
cleavage. For example, engineered hammerhead motif ribozyme
molecules may specifically and efficiently catalyze endonucleolytic
cleavage of sequences encoding SDHH.
[0132] Specific ribozyme cleavage sites within any potential RNA
target are initially identified by scanning the target molecule for
ribozyme cleavage sites, including the following sequences: GUA,
GUU, and GUC. Once identified, short RNA sequences of between 15
and 20 ribonucleotides, corresponding to the region of the target
gene containing the cleavage site, may be evaluated for secondary
structural features which may render the oligonucleotide
inoperable. The suitability of candidate targets may also be
evaluated by testing accessibility to hybridization with
complementary oligonucleotides using ribonuclease protection
assays.
[0133] Complementary ribonucleic acid molecules and ribozymes of
the invention may be prepared by any method known in the art for
the synthesis of nucleic acid molecules. These include techniques
for chemically synthesizing oligonucleotides such as solid phase
phosphoramidite chemical synthesis. Alternatively, RNA molecules
may be generated by in vitro and in vivo transcription of DNA
sequences encoding SDHH. Such DNA sequences may be incorporated
into a wide variety of vectors with suitable RNA polymerase
promoters such as T7 or SP6. Alternatively, these cDNA constructs
that synthesize complementary RNA, constitutively or inducibly, can
be introduced into cell lines, cells, or tissues.
[0134] RNA molecules may be modified to increase intracellular
stability and half-life. Possible modifications include, but are
not limited to, the addition of flanking sequences at the 5' and/or
3' ends of the molecule, or the use of phosphorothioate or 2'
O-methyl rather than phosphodiesterase linkages within the backbone
of the molecule. This concept is inherent in the production of PNAs
and can be extended in all of these molecules by the inclusion of
nontraditional bases such as inosine, queosine, and wybutosine, as
well as acetyl-, methyl-, thio-, and similarly modified forms of
adenine, cytidine, guanine, thyrnine, and uridine which are not as
easily recognized by endogenous endonucleases.
[0135] Many methods for introducing vectors into cells or tissues
are available and equally suitable for use in vivo, in vitro, and
ex vivo. For ex vivo therapy, vectors may be introduced into stem
cells taken from the patient and clonally propagated for autologous
transplant back into that same patient. Delivery by transfection,
by liposome injections, or by polycationic amino polymers may be
achieved using methods which are well known in the art. (See, e.g.,
Goldman, C. K. et al. (1997) Nature Biotechnology 15:462-466.)
[0136] Any of the therapeutic methods described above may be
applied to any subject in need of such therapy, including, for
example, mammals such as dogs, cats, cows, horses, rabbits,
monkeys, and most preferably, humans.
[0137] An additional embodiment of the invention relates to the
administration of a pharmaceutical or sterile composition, in
conjunction with a pharmaceutically acceptable carrier, for any of
the therapeutic effects discussed above. Such pharmaceutical
compositions may consist of SDHH, antibodies to SDHH, and mimetics,
agonists, antagonists, or inhibitors of SDHH. The compositions may
be administered alone or in combination with at least one other
agent, such as a stabilizing compound, which may be administered in
any sterile, biocompatible pharmaceutical carrier including, but
not limited to, saline, buffered saline, dextrose, and water. The
compositions may be administered to a patient alone, or in
combination with other agents, drugs, or hormones.
[0138] The pharmaceutical compositions utilized in this invention
may be administered by any number of routes including, but not
limited to, oral, intravenous, intramuscular, intra-arterial,
intramedullary, intrathecal, intraventricular, transdermal,
subcutaneous, intraperitoneal, intranasal, enteral, topical,
sublingual, or rectal means.
[0139] In addition to the active ingredients, these pharmaceutical
compositions may contain suitable pharmaceutically-acceptable
carriers comprising excipients and auxiliaries which facilitate
processing of the active compounds into preparations which can be
used pharmaceutically. Further details on techniques for
formulation and administration may be found in the latest edition
of Rernington's Pharmaceutical Sciences (Maack Publishing Co.,
Easton, Pa.).
[0140] Pharmaceutical compositions for oral administration can be
formulated using pharmaceutically acceptable carriers well known in
the art in dosages suitable for oral administration. Such carriers
enable the pharmaceutical compositions to be formulated as tablets,
pills, dragees, capsules, liquids, gels, syrups, slurries,
suspensions, and the like, for ingestion by the patient.
[0141] Pharmaceutical preparations for oral use can be obtained
through combining active compounds with solid excipient and
processing the resultant mixture of granules (optionally, after
grinding) to obtain tablets or dragee cores. Suitable auxiliaries
can be added, if desired. Suitable excipients include carbohydrate
or protein fillers, such as sugars, including lactose, sucrose,
mannitol, and sorbitol; starch from corn, wheat, rice, potato, or
other plants; cellulose, such as methyl cellulose,
hydroxypropylmethyl-cellulose, or sodium carboxymethylcellulose;
gums, including arabic and tragacanth; and proteins, such as
gelatin and collagen. If desired, disintegrating or solubilizing
agents may be added, such as the cross-linked polyvinyl
pyrrolidone, agar, and alginic acid or a salt thereof, such as
sodium alginate.
[0142] Dragee cores may be used in conjunction with suitable
coatings, such as concentrated sugar solutions, which may also
contain gum arabic, talc, polyvinylpyrrolidone, carbopol gel,
polyethylene glycol, and/or titanium dioxide, lacquer solutions,
and suitable organic solvents or solvent mixtures. Dyestuffs or
pigments may be added to the tablets or dragee coatings for product
identification or to characterize the quantity of active compound,
i.e., dosage.
[0143] Pharmaceutical preparations which can be used orally include
push-fit capsules made of gelatin, as well as soft, sealed capsules
made of gelatin and a coating, such as glycerol or sorbitol.
Push-fit capsules can contain active ingredients mixed with fillers
or binders, such as lactose or starches, lubricants, such as talc
or magnesium stearate, and, optionally, stabilizers. In soft
capsules, the active compounds may be dissolved or suspended in
suitable liquids, such as fatty oils, liquid, or liquid
polyethylene glycol with or without stabilizers.
[0144] Pharmaceutical formulations suitable for parenteral
administration may be formulated in aqueous solutions, preferably
in physiologically compatible buffers such as Hanks' solution,
Ringer's solution, or physiologically buffered saline. Aqueous
injection suspensions may contain substances which increase the
viscosity of the suspension, such as sodium carboxymethyl
cellulose, sorbitol, or dextran. Additionally, suspensions of the
active compounds may be prepared as appropriate oily injection
suspensions. Suitable lipophilic solvents or vehicles include fatty
oils, such as sesame oil, or synthetic fatty acid esters, such as
ethyl oleate, triglycerides, or liposomes. Non-lipid polycationic
amino polymers may also be used for delivery. Optionally, the
suspension may also contain suitable stabilizers or agents to
increase the solubility of the compounds and allow for the
preparation of highly concentrated solutions.
[0145] For topical or nasal administration, penetrants appropriate
to the particular barrier to be permeated are used in the
formulation. Such penetrants are generally known in the art.
[0146] The pharmaceutical compositions of the present invention may
be manufactured in a manner that is known in the art, e.g., by
means of conventional mixing, dissolving, granulating,
dragee-making, levigating, emulsifying, encapsulating, entrapping,
or lyophilizing processes.
[0147] The pharmaceutical composition may be provided as a salt and
can be formed with many acids, including but not limited to,
hydrochloric, sulfuric, acetic, lactic, tartaric, malic, and
succinic acid. Salts tend to be more soluble in aqueous or other
protonic solvents than are the corresponding free base forms. In
other cases, the preferred preparation may be a lyophilized powder
which may contain any or all of the following: 1 mM to 50 mM
histidine, 0.1% to 2% sucrose, and 2% to 7% mannitol, at a pH range
of 4.5 to 5.5, that is combined with buffer prior to use.
[0148] After pharmaceutical compositions have been prepared, they
can be placed in an appropriate container and labeled for treatment
of an indicated condition. For administration of SDHH, such
labeling would include amount, frequency, and method of
administration.
[0149] Pharmaceutical compositions suitable for use in the
invention include compositions wherein the active ingredients are
contained in an effective amount to achieve the intended purpose.
The determination of an effective dose is well within the
capability of those skilled in the art.
[0150] For any compound, the therapeutically effective dose can be
estimated initially either in cell culture assays, e.g., of
neoplastic cells or in animal models such as mice, rats, rabbits,
dogs, or pigs. An animal model may also be used to determine the
appropriate concentration range and route of administration. Such
information can then be used to determine useful doses and routes
for administration in humans.
[0151] A therapeutically effective dose refers to that amount of
active ingredient, for example SDHH or fragments thereof,
antibodies of SDHH, and agonists, antagonists or inhibitors of
SDHH, which ameliorates the symptoms or condition. Therapeutic
efficacy and toxicity may be determined by standard pharmaceutical
procedures in cell cultures or with experimental animals, such as
by calculating the ED.sub.50 (the dose therapeutically effective in
50% of the population) or LD.sub.50 (the dose lethal to 50% of the
population) statistics. The dose ratio of therapeutic to toxic
effects is the therapeutic index, and it can be expressed as the
ED.sub.50/LD.sub.50 ratio. Pharmaceutical compositions which
exhibit large therapeutic indices are preferred. The data obtained
from cell culture assays and animal studies are used to formulate a
range of dosage for human use. The dosage contained in such
compositions is preferably within a range of circulating
concentrations that includes the ED.sub.50 with little or no
toxicity. The dosage varies within this range depending upon the
dosage form employed, the sensitivity of the patient, and the route
of administration.
[0152] The exact dosage will be determined by the practitioner, in
light of factors related to the subject requiring treatment. Dosage
and administration are adjusted to provide sufficient levels of the
active moiety or to maintain the desired effect. Factors which may
be taken into account include the severity of the disease state,
the general health of the subject, the age, weight, and gender of
the subject, time and frequency of administration, drug
combination(s), reaction sensitivities, and response to therapy.
Long-acting pharmaceutical compositions may be administered every 3
to 4 days, every week, or biweekly depending on the half-life and
clearance rate of the particular formulation.
[0153] Normal dosage amounts may vary from about 0.1 .mu.g to
100,000 .mu.g, up to a total dose of about 1 gram, depending upon
the route of administration. Guidance as to particular dosages and
methods of delivery is provided in the literature and generally
available to practitioners in the art. Those skilled in the art
will employ different formulations for nucleotides than for
proteins or their inhibitors. Similarly, delivery of
polynucleotides or polypeptides will be specific to particular
cells, conditions, locations, etc.
[0154] Diagnostics
[0155] In another embodiment, antibodies which specifically bind
SDHH may be used for the diagnosis of disorders characterized by
expression of SDHH, or in assays to monitor patients being treated
with SDHH or agonists, antagonists, or inhibitors of SDHH.
Antibodies useful for diagnostic purposes may be prepared in the
same manner as described above for therapeutics. Diagnostic assays
for SDHH include methods which utilize the antibody and a label to
detect SDHH in human body fluids or in extracts of cells or
tissues. The antibodies may be used with or without modification,
and may be labeled by covalent or non-covalent attachment of a
reporter molecule. A wide variety of reporter molecules, several of
which are described above, are known in the art and may be
used.
[0156] A variety of protocols for measuring SDHH, including ELISAs,
RIAs, and FACS, are known in the art and provide a basis for
diagnosing altered or abnormal levels of SDHH expression. Normal or
standard values for SDHH expression are established by combining
body fluids or cell extracts taken from normal mammalian subjects,
preferably human, with antibody to SDHH under conditions suitable
for complex formation. The amount of standard complex formation may
be quantitated by various methods, preferably by photometric means.
Quantities of SDHH expressed in subject, control, and disease
samples from biopsied tissues are compared with the standard
values. Deviation between standard and subject values establishes
the parameters for diagnosing disease.
[0157] In another embodiment of the invention, the polynucleotides
encoding SDHH may be used for diagnostic purposes. The
polynucleotides which may be used include oligonucleotide
sequences, complementary RNA and DNA molecules, and PNAs. The
polynucleotides may be used to detect and quantitate gene
expression in biopsied tissues in which expression of SDHH may be
correlated with disease. The diagnostic assay may be used to
determine absence, presence, and excess expression of SDHH, and to
monitor regulation of SDHH levels during therapeutic
intervention.
[0158] In one aspect, hybridization with PCR probes which are
capable of detecting polynucleotide sequences, including genomic
sequences, encoding SDHH or closely related molecules may be used
to identify nucleic acid sequences which encode SDHH. The
specificity of the probe, whether it is made from a highly specific
region, e.g., the 5' regulatory region, or from a less specific
region, e.g., a conserved motif, and the stringency of the
hybridization or amplification (maximal, high, intermediate, or
low), will determine whether the probe identifies only naturally
occurring sequences encoding SDHH, allelic variants, or related
sequences.
[0159] Probes may also be used for the detection of related
sequences, and should preferably have at least 50% sequence
identity to any of the SDHH encoding sequences. The hybridization
probes of the subject invention may be DNA or RNA and may be
derived from the sequence of SEQ ID NO:2 or from genomic sequences
including promoters, enhancers, and introns of the SDHH gene.
[0160] Means for producing specific hybridization probes for DNAs
encoding SDHH include the cloning of polynucleotide sequences
encoding SDHH or SDHH derivatives into vectors for the production
of mRNA probes. Such vectors are known in the art, are commercially
available, and may be used to synthesize RNA probes in vitro by
means of the addition of the appropriate RNA polymerases and the
appropriate labeled nucleotides. Hybridization probes may be
labeled by a variety of reporter groups, for example, by
radionuclides such as .sup.32P or .sup.35S, or by enzymatic labels,
such as alkaline phosphatase coupled to the probe via avidin/biotin
coupling systems, and the like.
[0161] Polynucleotide sequences encoding SDHH may be used for the
diagnosis of a disorder associated with expression of SDHH.
Examples of such a disorder include, but are not limited to,
disorders of metabolism such as Addison's disease, cystic fibrosis,
diabetes, fatty hepatocirrhosis, galactosemia, goiter,
hyperadrenalism, hypoadrenalism, hyperparathyroidism,
hypoparathyroidism, hypercholesterolemia, hyperthyroidism,
hypothyroidism hyperlipidemia, hyperlipemia, lipid myopathies,
obesity, lipodystrophies, phenylketonuria, and renal failure; or a
cancer such as adenocarcinoma, leukemia, lymphoma, melanoma,
myeloma, sarcoma, teratocarcinoma, and, in particular, cancers of
the adrenal gland, bladder, bone, bone marrow, brain, breast,
cervix, gall bladder, ganglia, gastrointestinal tract, heart,
kidney, liver, lung, muscle, ovary, pancreas, parathyroid, penis,
prostate, salivary glands, skin, spleen, testis, thymus, thyroid,
and uterus. The polynucleotide sequences encoding SDHH may be used
in Southern or Northern analysis, dot blot, or other membrane-based
technologies; in PCR technologies; in dipstick, pin, and ELISA
assays; and in microarrays utilizing fluids or tissues from
patients to detect altered SDHH expression. Such qualitative or
quantitative methods are well known in the art.
[0162] In a particular aspect, the nucleotide sequences encoding
SDHH may be useful in assays that detect the presence of associated
disorders, particularly those mentioned above. The nucleotide
sequences encoding SDHH may be labeled by standard methods and
added to a fluid or tissue sample from a patient under conditions
suitable for the formation of hybridization complexes. After a
suitable incubation period, the sample is washed and the signal is
quantitated and compared with a standard value. If the amount of
signal in the patient sample is significantly altered in comparison
to a control sample then the presence of altered levels of
nucleotide sequences encoding SDHH in the sample indicates the
presence of the associated disorder. Such assays may also be used
to evaluate the efficacy of a particular therapeutic treatment
regimen in animal studies, in clinical trials, or to monitor the
treatment of an individual patient.
[0163] In order to provide a basis for the diagnosis of a disorder
associated with expression of SDHH, a normal or standard profile
for expression is established. This may be accomplished by
combining body fluids or cell extracts taken from normal subjects,
either animal or human, with a sequence, or a fragment thereof,
encoding SDHH, under conditions suitable for hybridization or
amplification. Standard hybridization may be quantified by
comparing the values obtained from normal subjects with values from
an experiment in which a known amount of a substantially purified
polynucleotide is used. Standard values obtained in this manner may
be compared with values obtained from samples from patients who are
symptomatic for a disorder. Deviation from standard values is used
to establish the presence of a disorder.
[0164] Once the presence of a disorder is established and a
treatment protocol is initiated, hybridization assays may be
repeated on a regular basis to determine if the level of expression
in the patient begins to approximate that which is observed in the
normal subject. The results obtained from successive assays may be
used to show the efficacy of treatment over a period ranging from
several days to months.
[0165] With respect to cancer, the presence of a relatively high
amount of transcript in biopsied tissue from an individual may
indicate a predisposition for the development of the disease, or
may provide a means for detecting the disease prior to the
appearance of actual clinical symptoms. A more definitive diagnosis
of this type may allow health professionals to employ preventative
measures or aggressive treatment earlier thereby preventing the
development or further progression of the cancer.
[0166] Additional diagnostic uses for oligonucleotides designed
from the sequences encoding SDHH may involve the use of PCR. These
oligomers may be chemically synthesized, generated enzymatically,
or produced in vitro. Oligomers will preferably contain a fragment
of a polynucleotide encoding SDHH, or a fragment of a
polynucleotide complementary to the polynucleotide encoding SDHH,
and will be employed under optimized conditions for identification
of a specific gene or condition. Oligomers may also be employed
under less stringent conditions for detection or quantitation of
closely related DNA or RNA sequences.
[0167] Methods which may also be used to quantitate the expression
of SDHH include radiolabeling or biotinylating nucleotides,
coamplification of a control nucleic acid, and interpolating
results from standard curves. (See, e.g., Melby, P. C. et al.
(1993) J. Immunol. Methods 159:235-244; and Duplaa, C. et al.
(1993) Anal. Biochem. 212:229-236.) The speed of quantitation of
multiple samples may be accelerated by running the assay in an
ELISA format where the oligomer of interest is presented in various
dilutions and a spectrophotometric or calorimetric response gives
rapid quantitation.
[0168] In further embodiments, oligonucleotides or longer fragments
derived from any of the polynucleotide sequences described herein
may be used as targets in a microarray. The microarray can be used
to monitor the expression level of large numbers of genes
simultaneously and to identify genetic variants, mutations, and
polymorphisms. This information may be used to determine gene
function, to understand the genetic basis of a disorder, to
diagnose a disorder, and to develop and monitor the activities of
therapeutic agents.
[0169] Microarrays may be prepared, used, and analyzed using
methods known in the art. (See, e.g., Brennan, T. M. et al. (1995)
U.S. Pat. No. 5,474,796; Schena, M. et al. (1996) Proc. Natl. Acad.
Sci. 93:10614-10619; Baldeschweiler et al. (1995) PCT application
WO95/251116; Shalon, D. et al. (1995) PCT application WO95/35505;
Heller, R. A. et al. (1997) Proc. Natl. Acad. Sci. 94:2150-2155;
and Heller, M. J. et al. (1997) U.S. Pat. No. 5,605,662.)
[0170] In another embodiment of the invention, nucleic acid
sequences encoding SDHH may be used to generate hybridization
probes useful in mapping the naturally occurring genomic sequence.
The sequences may be mapped to a particular chromosome, to a
specific region of a chromosome, or to artificial chromosome
constructions, e.g., human artificial chromosomes (HACs), yeast
artificial chromosomes (YACs), bacterial artificial chromosomes
(BACs), bacterial P1 constructions, or single chromosome cDNA
libraries. (See, e.g., Price, C. M. (1993) Blood Rev. 7:127-134;
and Trask, B. J. (1991) Trends Genet. 7:149-154.)
[0171] Fluorescent in situ hybridization (FISH) may be correlated
with other physical chromosome mapping techniques and genetic map
data. (See, e.g., Heinz-Ulrich, et al. (1995) in Meyers, R. A.
(ed.) Molecular Biology and Biotechnology, VCH Publishers New York,
N.Y., pp. 965-968.) Examples of genetic map data can be found in
various scientific journals or at the Online Mendelian Inheritance
in Man (OMIM) site. Correlation between the location of the gene
encoding SDHH on a physical chromosomal map and a specific
disorder, or a predisposition to a specific disorder, may help
define the region of DNA associated with that disorder. The
nucleotide sequences of the invention may be used to detect
differences in gene sequences among normal, carrier, and affected
individuals.
[0172] In situ hybridization of chromosomal preparations and
physical mapping techniques, such as linkage analysis using
established chromosomal markers, may be used for extending genetic
maps. Often the placement of a gene on the chromosome of another
mammalian species, such as mouse, may reveal associated markers
even if the number or arm of a particular human chromosome is not
known. New sequences can be assigned to chromosomal arms by
physical mapping. This provides valuable information to
investigators searching for disease genes using positional cloning
or other gene discovery techniques. Once the disease or syndrome
has been crudely localized by genetic linkage to a particular
genomic region, e.g., ataxia-telangiectasia to 11q22-23, any
sequences mapping to that area may represent associated or
regulatory genes for further investigation. (See, e.g., Gatti, R.
A. et al. (1988) Nature 336:577-580.) The nucleotide sequence of
the subject invention may also be used to detect differences in the
chromosomal location due to translocation, inversion, etc., among
normal, carrier, or affected individuals.
[0173] In another embodiment of the invention, SDHH, its catalytic
or immunogenic fragments, or oligopeptides thereof can be used for
screening libraries of compounds in any of a variety of drug
screening techniques. The fragment employed in such screening may
be free in solution, affixed to a solid support, borne on a cell
surface, or located intracellularly. The formation of binding
complexes between SDHH and the agent being tested may be
measured.
[0174] Another technique for drug screening provides for high
throughput screening of compounds having suitable binding affinity
to the protein of interest. (See, e.g., Geysen, et al. (1984) PCT
application WO84/03564.) In this method, large numbers of different
small test compounds are synthesized on a solid substrate, such as
plastic pins or some other surface. The test compounds are reacted
with SDHH, or fragments thereof, and washed. Bound SDHH is then
detected by methods well known in the art. Purified SDHH can also
be coated directly onto plates for use in the aforementioned drug
screening techniques. Alternatively, non-neutralizing antibodies
can be used to capture the peptide and immobilize it on a solid
support.
[0175] In another embodiment, one may use competitive drug
screening assays in which neutralizing antibodies capable of
binding SDHH specifically compete with a test compound for binding
SDHH. In this manner, antibodies can be used to detect the presence
of any peptide which shares one or more antigenic determinants with
SDHH.
[0176] In additional embodiments, the nucleotide sequences which
encode SDHH may be used in any molecular biology techniques that
have yet to be developed, provided the new techniques rely on
properties of nucleotide sequences that are currently known,
including, but not limited to, such properties as the triplet
genetic code and specific base pair interactions.
[0177] The examples below are provided to illustrate the subject
invention and are not included for the purpose of limiting the
invention.
EXAMPLES
[0178] I. THP1AZS08 cDNA Library Construction
[0179] This subtracted THP-1 promonocyte cell line library was
constructed using 5.76 million clones from a 5-aza-2'-deoxycytidine
(AZ) treated THP-1 cell library. THP-1 (ATCC TIB 202) is a human
promonocyte line derived from peripheral blood of a 1-year-old
Caucasian male with acute monocytic leukemia. Starting RNA was made
from THP-1 promonocyte cells treated for three days with 0.8
micromolar AZ.
[0180] The frozen cells were homogenized and lysed using a POLYTRON
PT-3000 homogenizer (Brinkmann Instruments, Westbury, N.Y.) in
guanidinium isothiocyanate solution. The lysate was centrifuged
over a 5.7 M CsCl cushion using a Beckman SW28 rotor in a Beckman
L8-70M ultracentrifuge (Beckman Instruments) for 18 hours at 25,000
rpm at ambient temperature. The mRNA was extracted with acid phenol
pH 4.7, precipitated using 0.3 M sodium acetate and 2.5 volumes of
ethanol, resuspended in RNAse-free water, and treated with DNase at
37.degree. C. The RNA was extracted and precipitated as before. The
mRNA was isolated with the OLIGOTEX kit (QIAGEN, Inc., Chatsworth,
Calif.) and used to construct the THP1AZT02 cDNA library. The
library was oligo(dT)-primed, and cDNAs were cloned directionally
into the PSPORT1 vectoring system using Sal1 (5') and NotI
(3').
[0181] The mRNA was handled according to the recommended protocols
in the SUPERSCRIPT plasmid system for cDNA synthesis and plasmid
cloning (Gibco/BRL). The cDNAs were fractionated on a SEPHAROSE
CLAB column (Pharmacia), and those cDNAs exceeding 400 bp were
ligated into PSPORT 1. The plasmid PSPORT 1 was subsequently
transformed into DH5.alpha. competent cells (Gibco/BRL).
[0182] THP1AZS08 was constructed by subtraction of an untreated
control THP1 cell line library (5.times.10.sup.6 THP1NOT02 clones)
from a 5-aza-2'-deoxycytidine-treated THP1 cell line library. These
plasmid libraries were grown in E. coli strain DH12S (Gibco/BRL)
liquid culture under carbenicillin (25 mg/L) and methicillin (1
mg/ml) selection following transformation by electroporation. The
cultures were checked spectrophotometrically (Model DU-7
Spectrophotometer, Beckman Instruments) and allowed to grow to an
OD600 of 0.2, and then superinfected with a 5-fold excess of the
helper phage M13K07 according to the method of Vieira et al.
(Methods Enzymol. (1987) 153:3-11).
[0183] To enrich for 5-aza-2'-deoxycytidine induced transcripts,
the cDNA library was then subtracted in two rounds of hybridization
using a methodology adapted from Swaroop et al. (NAR (1991)
19:1954). The THP1AZT02 single-stranded library was gel and
hydroxyapatite purified according to the method described in Soares
et al. (Proc. Natl. Acad. Sci. (1994) 91:9228-9232.) The
hybridization probe for subtraction, THP1NOT02 was generated by in
vitro transcription using the MEGASCRIPT kit (Ambion, Austin Tex.)
with SP6 RNA polymerase and 40% biotin-14-CTP (Gibco/BRL) following
linearization of the double stranded plasmid DNA with Eco RI. The
purified single-stranded template DNA was prehybridized according
to the method of Bonaldo et al. (Genome Research (1996) 6:791); and
hybridized as described in Soares, supra. In each round of
subtraction, the single stranded cDNA library derived from the
5-aza-2'-deoxycytidine-treated cells was hybridized for 48 hours
with a 300:1 molar ratio of biotinylated riboprobe derived from the
control cell library, THP1NOT02. Following each hybridization step,
the single stranded DNA (subtracted library) was purified by
streptavidin coated magnetic beads (DYNAL, Lake Success N.Y.)
according to the manufacturers specifications. Following the second
streptavidin separation, the single stranded subtracted library was
converted to partially double-stranded by random priming, and
electroporated into DH10B competent bacteria (Gibco/BRL).
[0184] II. Isolation and Sequencing of cDNA Clones
[0185] Plasmid DNA was released from the cells and purified using
the REAL PREP 96 plasmid kit for rapid extraction alkaline lysis
plasmid minipreps (QIAGEN, Inc.). This kit enabled the simultaneous
purification of 96 samples in a 96-well block using multi-channel
reagent dispensers. The recommended protocol was employed except
for the following changes: 1) the bacteria were cultured in 1 ml of
sterile Terrific Broth (LIFE TECHNOLOGIES) with carbenicillin at 25
mg/L and glycerol at 0.4%; 2) after inoculation, the cultures were
incubated for 19 hours and at the end of incubation, the cells were
lysed with 0.3 ml of lysis buffer; and 3) following isopropanol
precipitation, the plasmid DNA pellet was resuspended in 0.1 ml of
distilled water. After the last step in the protocol, samples were
transferred to a 96-well block for storage at 4.degree. C.
[0186] The cDNAs were sequenced by the method of Sanger et al.
(1975, J. Mol. Biol. 94:441f), using a MICRO LAB 2200 liquid
transfer system (Hamilton, Reno, Nev.) in combination with Peltier
thermal cyclers (PTC200 from MJ Research, Watertown, Mass.) and 377
DNA sequencing systems (Applied Biosystems); and the reading frame
was determined.
[0187] III. Similarity Searching of cDNA Clones and Their Deduced
Proteins
[0188] The nucleotide sequences and/or amino acid sequences of the
Sequence Listing were used to query sequences in the GenBank,
SwissProt, BLOCKS, and Pima II databases. These databases, which
contain previously identified and annotated sequences, were
searched for regions of similarity using BLAST (Basic Local
Alignment Search Tool). (See, e.g., Altschul, S. F. (1993) J. Mol.
Evol 36:290-300; and Altschul et al. (1990) J. Mol. Biol.
215:403-410.)
[0189] BLAST produced alignments of both nucleotide and amino acid
sequences to determine sequence similarity. Because of the local
nature of the alignments, BLAST was especially useful in
determining exact matches or in identifying homologs which may be
of prokaryotic (bacterial) or eukaryotic (animal, fungal, or plant)
origin. Other algorithms could have been used when dealing with
primary sequence patterns and secondary structure gap penalties.
(See, e.g., Smith, T. et al. (1992) Protein Engineering 5:35-51.)
The sequences disclosed in this application have lengths of at
least 49 nucleotides and have no more than 12% uncalled bases
(where N is recorded rather than A, C, G, or T).
[0190] The BLAST approach searched for matches between a query
sequence and a database sequence. BLAST evaluated the statistical
significance of any matches found, and reported only those matches
that satisfy the user-selected threshold of significance. In this
application, threshold was set at 10.sup.-25 for nucleotides and
10.sup.-8 for peptides.
[0191] Incyte nucleotide sequences were searched against the
GenBank databases for primate (pri), rodent (rod), and other
mammalian sequences (mam), and deduced amino acid sequences from
the same clones were then searched against GenBank functional
protein databases, mammalian (mamp), vertebrate (vrtp), and
eukaryote (eukp), for similarity.
[0192] Additionally, sequences identified from cDNA libraries may
be analyzed to identify those gene sequences encoding conserved
protein motifs using an appropriate analysis program, e.g., BLOCKS.
BLOCKS is a weighted matrix analysis algorithm based on short amino
acid segments, or blocks, compiled from the PROSITE database.
(Bairoch, A. et al. (1997) Nucleic Acids Res. 25:217-221.) The
BLOCKS algorithm is useful for classifying genes with unknown
functions. (Henikoff S. And Henikoff G. J., Nucleic Acids Research
(1991) 19:6565-6572.) Blocks, which are 3-60 amino acids in length,
correspond to the most highly conserved regions of proteins. The
BLOCKS algorithm compares a query sequence with a weighted scoring
matrix of blocks in the BLOCKS database. Blocks in the BLOCKS
database are calibrated against protein sequences with known
functions from the SWISS-PROT database to determine the stochastic
distribution of matches. Similar databases such as PRINTS, a
protein fingerprint database, are also searchable using the BLOCKS
algorithm. (Attwood, T. K. et al. (1997) J. Chem. Inf. Comput. Sci.
37:417-424.) PRINTS is based on non-redundant sequences obtained
from sources such as SWISS-PROT, GenBank, PIR, and NRL-3D.
[0193] The BLOCKS algorithm searches for matches between a query
sequence and the BLOCKS or PRINTS database and evaluates the
statistical significance of any matches found. Matches from a
BLOCKS or PRINTS search can be evaluated on two levels, local
similarity and global similarity. The degree of local similarity is
measured by scores, and the extent of global similarity is measured
by score ranking and probability values. A score of 1000 or greater
for a BLOCKS match of highest ranking indicates that the match
falls within the 0.5 percentile level of false positives when the
matched block is calibrated against SWISS-PROT. Likewise, a
probability value of less than 1.0.times.10.sup.-3 indicates that
the match would occur by chance no more than one time in every 1000
searches. Only those matches with a cutoff score of 1000 or greater
and a cutoff probability value of 1.0.times.10.sup.-3 or less are
considered in the functional analyses of the protein sequences in
the Sequence Listing.
[0194] Nucleic and amino acid sequences of the Sequence Listing may
also be analyzed using PFAM. PFAM is a Hidden Markov Model (HMM)
based protocol useful in protein family searching. HMM is a
probabilistic approach which analyzes consensus primary structures
of gene families. (See, e.g., Eddy, S. R. (1996) Cur. Opin. Str.
Biol. 6:361-365.)
[0195] The PFAM database contains protein sequences of 527 protein
families gathered from publicly available sources, e.g., SWISS-PROT
and PROSITE. PFAM searches for well characterized protein domain
families using two high-quality alignment routines, seed alignment
and full alignment. (See, e.g., Sonnhammer, E. L. L. et al. (1997)
Proteins 28:405-420.) The seed alignment utilizes the hmmls
program, a program that searches for local matches, and a
non-redundant set of the PFAM database. The full alignment utilizes
the hmmfs program, a program that searches for multiple fragments
in long sequences, e.g., repeats and motifs, and all sequences in
the PFAM database. A result or score of 100 "bits" can signify that
it is 2.sup.100-fold more likely that the sequence is a true match
to the model or comparison sequence. Cutoff scores which range from
10 to 50 bits are generally used for individual protein families
using the SWISS-PROT sequences as model or comparison
sequences.
[0196] Two other algorithms, SIGPEPT and TM, both based on the HMM
algorithm described above (see, e.g., Eddy, supra; and Sonnhammer,
supra), identify potential signal sequences and transmembrane
domains, respectively. SIGPEPT was created using protein sequences
having signal sequence annotations derived from SWISS-PROT. It
contains about 1413 non-redundant signal sequences ranging in
length from 14 to 36 amino acid residues. TM was created similarly
using transmembrane domain annotations. It contains about 453
non-redundant transmembrane sequences encompassing 1579
transmembrane domain segments. Suitable HMM models were constructed
using the above sequences and were refined with known SWISS-PROT
signal peptide sequences or transmembrane domain sequences until a
high correlation coefficient, a measurement of the correctness of
the analysis, was obtained. Using the protein sequences from the
SWISS-PROT database as a test set, a cutoff score of 11 bits, as
determined above, correlated with 91-94% true-positives and about
4.1% false-positives, yielding a correlation coefficient of about
0.87-0.90 for SIGPEPT. A score of 11 bits for TM will typically
give the following results: 75% true positives; 1.72% false
positives; and a correlation coefficient of 0.76. Each search
evaluates the statistical significance of any matches found and
reports only those matches that score at least 11 bits.
[0197] IV. Northern Analysis
[0198] Northern analysis is a laboratory technique used to detect
the presence of a transcript of a gene and involves the
hybridization of a labeled nucleotide sequence to a membrane on
which RNAs from a particular cell type or tissue have been bound.
(See, e.g., Sambrook, supra, ch. 7; and Ausubel, supra, ch. 4 and
16.)
[0199] Analogous computer techniques applying BLAST are used to
search for identical or related molecules in nucleotide databases
such as GenBank or LIFESEQ database (Incyte Pharmaceuticals). This
analysis is much faster than multiple membrane-based
hybridizations. In addition, the sensitivity of the computer search
can be modified to determine whether any particular match is
categorized as exact or similar.
[0200] The basis of the search is the product score, which is
defined as: 1 % sequence identity .times. % maximum BLAST score
100
[0201] The product score takes into account both the degree of
similarity between two sequences and the length of the sequence
match. For example, with a product score of 40, the match will be
exact within a 1% to 2% error, and, with a product score of 70, the
match will be exact. Similar molecules are usually identified by
selecting those which show product scores between 15 and 40,
although lower scores may identify related molecules.
[0202] The results of Northern analysis are reported as a list of
libraries in which the transcript encoding SDHH occurs. Abundance
and percent abundance are also reported. Abundance directly
reflects the number of times a particular transcript is represented
in a cDNA library, and percent abundance is abundance divided by
the total number of sequences examined in the cDNA library.
[0203] V. Extension of SDHH Encoding Polynucleotides
[0204] The nucleic acid sequence of Incyte Clone 2752518 was used
to design oligonucleotide primers for extending a partial
nucleotide sequence to full length. One primer was synthesized to
initiate extension of an antisense polynucleotide, and the other
was synthesized to initiate extension of a sense polynucleotide.
Primers were used to facilitate the extension of the known sequence
"outward" generating amplicons containing new unknown nucleotide
sequence for the region of interest. The initial primers were
designed from the cDNA using OLIGO 4.06 (National Biosciences,
Plymouth, Minn.), or another appropriate program, to be about 22 to
30 nucleotides in length, to have a GC content of about 50% or
more, and to anneal to the target sequence at temperatures of about
68.degree. C. to about 72.degree. C. Any stretch of nucleotides
which would result in hairpin structures and primer-primer
dimerizations was avoided.
[0205] Selected human cDNA libraries (GIBCO BRL) were used to
extend the sequence. If more than one extension is necessary or
desired, additional sets of primers are designed to further extend
the known region.
[0206] High fidelity amplification was obtained by following the
instructions for the XL-PCR kit (Perkin Elmer) and thoroughly
mixing the enzyme and reaction mix. PCR was performed using the
Peltier thermal cycler (PTC200; M. J. Research, Watertown, Mass.),
beginning with 40 pmol of each primer and the recommended
concentrations of all other components of the kit, with the
following parameters:
1 Step 1 94.degree. C. for 1 min (initial denaturation) Step 2
65.degree. C. for 1 min Step 3 68.degree. C. for 6 min Step 4
94.degree. C. for 15 sec Step 5 65.degree. C. for 1 min Step 6
68.degree. C. for 7 min Step 7 Repeat steps 4 through 6 for an
additional 15 cycles Step 8 94.degree. C. for 15 sec Step 9
65.degree. C. for 1 min Step 10 68.degree. C. for 7:15 min Step 11
Repeat steps 8 through 10 for an additional 12 cycles Step 12
72.degree. C. for 8 min Step 13 4.degree. C. (and holding)
[0207] A 5 .mu.l to 10 .mu.l aliquot of the reaction mixture was
analyzed by electrophoresis on a low concentration (about 0.6% to
0.8%) agarose mini-gel to determine which reactions were successful
in extending the sequence. Bands thought to contain the largest
products were excised from the gel, purified using QIAQUICK (QIAGEN
Inc.), and trimmed of overhangs using Klenow enzyme to facilitate
religation and cloning.
[0208] After ethanol precipitation, the products were redissolved
in 13 .mu.l of ligation buffer, 1 .mu.l T4-DNA ligase (15 units)
and 1 .mu.l T4 polynucleotide kinase were added, and the mixture
was incubated at room temperature for 2 to 3 hours, or overnight at
16.degree. C. Competent E. coli cells (in 40 .mu.l of appropriate
media) were transformed with 3 .mu.l of ligation mixture and
cultured in 80 .mu.l of SOC medium. (See, e.g., Sambrook, supra,
Appendix A, p. 2.) After incubation for one hour at 37.degree. C.,
the E. coli mixture was plated on Luria Bertani (LB) agar (See,
e.g., Sambrook, supra, Appendix A, p. 1) containing carbenicillin
(2.times. carb). The following day, several colonies were randomly
picked from each plate and cultured in 150 .mu.l of liquid
LB/2.times. carb medium placed in an individual well of an
appropriate commercially-available sterile 96-well microtiter
plate. The following day, 5 .mu.l of each overnight culture was
transferred into a non-sterile 96-well plate and, after dilution
1:10 with water, 5 .mu.l from each sample was transferred into a
PCR array.
[0209] For PCR amplification, 18 .mu.l of concentrated PCR reaction
mix (3.3.times.) containing 4 units of rTth DNA polymerase, a
vector primer, and one or both of the gene specific primers used
for the extension reaction were added to each well. Amplification
was performed using the following conditions:
2 Step 1 94.degree. C. for 60 sec Step 2 94.degree. C. for 20 sec
Step 3 55.degree. C. for 30 sec Step 4 72.degree. C. for 90 sec
Step 5 Repeat steps 2 through 4 for an additional 29 cycles Step 6
72.degree. C. for 180 sec Step 7 4.degree. C. (and holding)
[0210] Aliquots of the PCR reactions were run on agarose gels
together with molecular weight markers. The sizes of the PCR
products were compared to the original partial cDNAs, and
appropriate clones were selected, ligated into plasmid, and
sequenced.
[0211] In like manner, the nucleotide sequence of SEQ ID NO:2 is
used to obtain 5' regulatory sequences using the procedure above,
oligonucleotides designed for 5' extension, and an appropriate
genomic library.
[0212] VI. Labeling and Use of Individual Hybridization Probes
[0213] Hybridization probes derived from SEQ ID NO:2 are employed
to screen cDNAs, genomic DNAs, or mRNAs. Although the labeling of
oligonucleotides, consisting of about 20 base pairs, is
specifically described, essentially the same procedure is used with
larger nucleotide fragments. Oligonucleotides are designed using
state-of-the-art software such as OLIGO 4.06 software (National
Biosciences) and labeled by combining 50 pmol of each oligomer, 250
.mu.Ci of [.gamma.-.sup.32P] adenosine triphosphate (Amersham,
Chicago, Ill.), and T4 polynucleotide kinase (DuPont NEN, Boston,
Mass.). The labeled oligonucleotides are substantially purified
using a SEPHADEX G-25 superfine size exclusion dextran bead column
(Pharmacia & Upjohn, Kalamazoo, Mich.). An aliquot containing
10.sup.7 counts per minute of the labeled probe is used in a
typical membrane-based hybridization analysis of human genomic DNA
digested with one of the following endonucleases: Ase I, Bgl II,
Eco RI, Pst I, Xbal, or Pvu II (DuPont NEN, Boston, Mass.).
[0214] The DNA from each digest is fractionated on a 0.7% agarose
gel and transferred to nylon membranes (Nytran Plus, Schleicher
& Schuell, Durham, N.H.). Hybridization is carried out for 16
hours at 40.degree. C. To remove nonspecific signals, blots are
sequentially washed at room temperature under increasingly
stringent conditions up to 0.1.times. saline sodium citrate and
0.5% sodium dodecyl sulfate. After XOMAT AR film (Kodak, Rochester,
N.Y.) is exposed to the blots for several hours, hybridization
patterns are compared visually.
[0215] VII. Microarrays
[0216] A chemical coupling procedure and an ink jet device can be
used to synthesize array elements on the surface of a substrate.
(See, e.g., Baldeschweiler, supra.) An array analogous to a dot or
slot blot may also be used to arrange and link elements to the
surface of a substrate using thermal, UV, chemical, or mechanical
bonding procedures. A typical array may be produced by hand or
using available methods and machines and contain any appropriate
number of elements. After hybridization, nonhybridized probes are
removed and a scanner used to determine the levels and patterns of
fluorescence. The degree of complementarity and the relative
abundance of each probe which hybridizes to an element on the
microarray may be assessed through analysis of the scanned
images.
[0217] Full-length cDNAs, Expressed Sequence Tags (ESTs), or
fragments thereof may comprise the elements of the microarray.
Fragments suitable for hybridization can be selected using software
well known in the art such as LASERGENE. Full-length cDNAs, ESTs,
or fragments thereof corresponding to one of the nucleotide
sequences of the present invention, or selected at random from a
cDNA library relevant to the present invention, are arranged on an
appropriate substrate, e.g., a glass slide. The cDNA is fixed to
the slide using, e.g., UV cross-linking followed by thermal and
chemical treatments and subsequent drying. (See, e.g., Schena, M.
et al. (1995) Science 270:467-470; and Shalon, D. et al. (1996)
Genome Res. 6:639-645.) Fluorescent probes are prepared and used
for hybridization to the elements on the substrate. The substrate
is analyzed by procedures described above.
[0218] VIII. Complementary Polynucleotides
[0219] Sequences complementary to the SDHH-encoding sequences, or
any parts thereof, are used to detect, decrease, or inhibit
expression of naturally occurring SDHH. Although use of
oligonucleotides comprising from about 15 to 30 base pairs is
described, essentially the same procedure is used with smaller or
with larger sequence fragments. Appropriate oligonucleotides are
designed using OLIGO 4.06 software and the coding sequence of SDHH.
To inhibit transcription, a complementary oligonucleotide is
designed from the most unique 5' sequence and used to prevent
promoter binding to the coding sequence. To inhibit translation, a
complementary oligonucleotide is designed to prevent ribosomal
binding to the SDHH-encoding transcript.
[0220] IX. Expression of SDHH
[0221] Expression and purification of SDHH is achieved using
bacterial or virus-based expression systems. For expression of SDHH
in bacteria, cDNA is subcloned into an appropriate vector
containing an antibiotic resistance gene and an inducible promoter
that directs high levels of cDNA transcription. Examples of such
promoters include, but are not limited to, the trp-lac (tac) hybrid
promoter and the T5 or T7 bacteriophage promoter in conjunction
with the lac operator regulatory element. Recombinant vectors are
transformed into suitable bacterial hosts, e.g., BL21(DE3).
Antibiotic resistant bacteria express SDHH upon induction with
isopropyl beta-D-thiogalactopyranoside (IPTG). Expression of SDHH
in eukaryotic cells is achieved by infecting insect or mammalian
cell lines with recombinant Autographica californica nuclear
polyhedrosis virus (AcMNPV), commonly known as baculovirus. The
nonessential polyhedrin gene of baculovirus is replaced with cDNA
encoding SDHH by either homologous recombination or
bacterial-mediated transposition involving transfer plasmid
intermediates. Viral infectivity is maintained and the strong
polyhedrin promoter drives high levels of cDNA transcription.
Recombinant baculovirus is used to infect Spodoptera frugiperda
(Sf9) insect cells in most cases, or human hepatocytes, in some
cases. Infection of the latter requires additional genetic
modifications to baculovirus. (See Engelhard, E. K. et al. (1994)
Proc. Natl. Acad. Sci. USA 91:3224-3227; Sandig, V. et al. (1996)
Hum. Gene Ther. 7:1937-1945.)
[0222] In most expression systems, SDHH is synthesized as a fusion
protein with, e.g., glutathione S-transferase (GST) or a peptide
epitope tag, such as FLAG or 6-His, permitting rapid, single-step,
affinity-based purification of recombinant fusion protein from
crude cell lysates. GST, a 26-kilodalton enzyme from Schistosoma
japonicum, enables the purification of fusion proteins on
immobilized glutathione under conditions that maintain protein
activity and antigenicity (Pharmacia, Piscataway, N.J.). Following
purification, the GST moiety can be proteolytically cleaved from
SDHH at specifically engineered sites. FLAG, an 8-amino acid
peptide, enables immunoaffinity purification using commercially
available monoclonal and polyclonal anti-FLAG antibodies (Eastman
Kodak, Rochester, N.Y.). 6-His, a stretch of six consecutive
histidine residues, enables purification on metal-chelate resins
(QIAGEN Inc, Chatsworth, Calif.). Methods for protein expression
and purification are discussed in Ausubel, F. M. et al. (1995 and
periodic supplements) Current Protocols in Molecular Biology, John
Wiley & Sons, New York, N.Y., ch 10, 16. Purified SDHH obtained
by these methods can be used directly in the following activity
assay.
[0223] X. Demonstration of SDHH Activity
[0224] SDHH activity may be conveniently determined by measuring
the conversion of serine to pyruvate. (Suda et al. (1970) Meth.
Enzymol.17B:346-351.) A solution of 1 M serine in 0.1 M potassium
phosphate buffer, pH 8.0 is prepared and stored at -20.degree. C.
The enzyme is combined with 0.1 ml 5.times.10.sup.-4 M pyridoxal
phosphate, 0.5 ml 0.2 M phosphate buffer at pH 8 containing
2.times.10.sup.-3 M EDTA, the volume is adjusted to 0.9 ml with
water, and the solution is warmed in a 37.degree. C. water bath for
5 minutes. 0.1 ml of the serine solution warmed to 37.degree. C. is
added and incubated for 5 minutes at 37.degree. C. The reaction is
stopped with 0.5 ml of 10% trichloroacetic acid. The preparation
kept in an ice bath for 10 minutes. Any precipitate is removed by
centrifugation. A 0.5 ml aliquot is combined with 0.5 ml 0.033%
2,4-dinitrophenylhydrazine solution in 2N HCl and the mixture is
allowed to stand for at least 5 minutes at approximately
20.degree.. Any pyruvate formed is converted to the hydrazine in
the presence of 2,4-dinitrophenylhydrazine. 2 ml of 2N sodium
hydroxide solution is added to stop the reaction. The absorbance of
the reaction mixture is read at 520 nm within 5 minutes, using a
spectrophotometer. Absorbance at this frequency is proportional to
the SDHH activity in the original sample. For a control,
trichloroacetic acid is added to the reaction mixture prior to the
addition of the substrate.
[0225] XI. Functional Assays
[0226] SDHH function is assessed by expressing the sequences
encoding SDHH at physiologically elevated levels in mammalian cell
culture systems. cDNA is subcloned into a mammalian expression
vector containing a strong promoter that drives high levels of cDNA
expression. Vectors of choice include PCMV SPORT (Life
Technologies, Gaithersburg, Md.) and PCR 3.1 (Invitrogen, Carlsbad,
Calif., both of which contain the cytomegalovirus promoter. 5-10
.mu.g of recombinant vector are transiently transfected into a
human cell line, preferably of endothelial or hematopoietic origin,
using either liposome formulations or electroporation. 1-2 .mu.g of
an additional plasmid containing sequences encoding a marker
protein are co-transfected. Expression of a marker protein provides
a means to distinguish transfected cells from nontransfected cells
and is a reliable predictor of cDNA expression from the recombinant
vector. Marker proteins of choice include, e.g., Green Fluorescent
Protein (GFP) (Clontech, Palo Alto, Calif.), CD64, or a CD64-GFP
fusion protein. Flow cytometry (FCM), an automated, laser
optics-based technique, is used to identify transfected cells
expressing GFP or CD64-GFP, and to evaluate properties, for
example, their apoptotic state. FCM detects and quantifies the
uptake of fluorescent molecules that diagnose events preceding or
coincident with cell death. These events include changes in nuclear
DNA content as measured by staining of DNA with propidium iodide;
changes in cell size and granularity as measured by forward light
scatter and 90 degree side light scatter; down-regulation of DNA
synthesis as measured by decrease in bromodeoxyuridine uptake;
alterations in expression of cell surface and intracellular
proteins as measured by reactivity with specific antibodies; and
alterations in plasma membrane composition as measured by the
binding of fluorescein-conjugated Annexin V protein to the cell
surface. Methods in flow cytometry are discussed in Ormerod, M. G.
(1994) Flow Cytometry, Oxford, New York, N.Y.
[0227] The influence of SDHH on gene expression can be assessed
using highly purified populations of cells transfected with
sequences encoding SDHH and either CD64 or CD64-GFP. CD64 and
CD64-GFP are expressed on the surface of transfected cells and bind
to conserved regions of human immunoglobulin G (IgG). Transfected
cells are efficiently separated from nontransfected cells using
magnetic beads coated with either human IgG or antibody against
CD64 (DYNAL). mRNA can be purified from the cells using methods
well known by those of skill in the art. Expression of mRNA
encoding SDHH and other genes of interest can be analyzed by
Northern analysis or microarray techniques.
[0228] XII. Production of SDHH Specific Antibodies
[0229] SDHH substantially purified using polyacrylamide gel
electrophoresis (PAGE)(see, e.g., Harrington, M. G. (1990) Methods
Enzymol. 182:488-495), or other purification techniques, is used to
immunize rabbits and to produce antibodies using standard
protocols.
[0230] Alternatively, the SDHH amino acid sequence is analyzed
using LASERGENE software (DNASTAR Inc.) to determine regions of
high immunogenicity, and a corresponding oligopeptide is
synthesized and used to raise antibodies by means known to those of
skill in the art. Methods for selection of appropriate epitopes,
such as those near the C-terminus or in hydrophilic regions are
well described in the art. (See, e.g., Ausubel supra, ch. 11.)
[0231] Typically, oligopeptides 15 residues in length are
synthesized using an Applied Biosystems Model 431A peptide
synthesizer using fmoc-chemistry and coupled to KLH (Sigma, St.
Louis, Mo.) by reaction with
N-maleimidobenzoyl-N-hydroxysuccinimide ester (MBS) to increase
immunogenicity. (See, e.g., Ausubel supra.) Rabbits are immunized
with the oligopeptide-KLH complex in complete Freund's adjuvant.
Resulting antisera are tested for antipeptide activity by, for
example, binding the peptide to plastic, blocking with 1% BSA,
reacting with rabbit antisera, washing, and reacting with
radio-iodinated goat anti-rabbit IgG.
[0232] XIII. Purification of Naturally Occurring SDHH Using
Specific Antibodies
[0233] Naturally occurring or recombinant SDHH is substantially
purified by immunoaffinity chromatography using antibodies specific
for SDHH. An immunoaffinity column is constructed by covalently
coupling anti-SDHH antibody to an activated chromatographic resin,
such as CNBr-activated SEPHAROSE (Pharmacia & Upjohn). After
the coupling, the resin is blocked and washed according to the
manufacturer's instructions.
[0234] Media containing SDHH are passed over the immunoaffinity
column, and the column is washed under conditions that allow the
preferential absorbance of SDHH (e.g., high ionic strength buffers
in the presence of detergent). The column is eluted under
conditions that disrupt antibody/SDHH binding (e.g., a buffer of pH
2 to pH 3, or a high concentration of a chaotrope, such as urea or
thiocyanate ion), and SDHH is collected.
[0235] XIV. Identification of Molecules Which Interact with
SDHH
[0236] SDHH, or biologically active fragments thereof, are labeled
with 1251 Bolton-Hunter reagent. (See, e.g., Bolton et al. (1973)
Biochem. J. 133:529.) Candidate molecules previously arrayed in the
wells of a multi-well plate are incubated with the labeled SDHH,
washed, and any wells with labeled SDHH complex are assayed. Data
obtained using different concentrations of SDHH are used to
calculate values for the number, affinity, and association of SDHH
with the candidate molecules.
[0237] Various modifications and variations of the described
methods and systems of the invention will be apparent to those
skilled in the art without departing from the scope and spirit of
the invention. Although the invention has been described in
connection with specific preferred embodiments, it should be
understood that the invention as claimed should not be unduly
limited to such specific embodiments. Indeed, various modifications
of the described modes for carrying out the invention which are
obvious to those skilled in molecular biology or related fields are
intended to be within the scope of the following claims.
Sequence CWU 1
1
* * * * *