Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0024141 (systemic lupus erythematosus)
 44,322 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Patients with systemic lupus erythematosus (SLE) produce autoantibodies against a variety of nuclear antigens including Ki antigen. Although anti-Ki autoantibodies were found in a significant number of SLE patients, the nature of Ki antigen is poorly characterized. By using anti-Ki serum as a probe we have cloned a bovine cDNA directing the synthesis in Escherichia coli of a polypeptide immunologically indistinguishable from the authentic Ki antigen. A homologous human cDNA was also cloned and its nucleotide sequence predicted the entire primary structure of a novel nuclear protein with a molecular weight of 29 508 and with highly hydrophilic and weakly acidic character. The gene is highly conserved not only in the coding region but also in the 3'-untranslated region. The bacterially produced Ki antigen would be valuable for diagnosis of SLE.
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PMID:Cloning and nucleotide sequence of cDNA for Ki antigen, a highly conserved nuclear protein detected with sera from patients with systemic lupus erythematosus. 196 96

The identification of cellular proteins involved in the control of cell proliferation in normal cells is essential for understanding the mechanism underlying growth regulation and cellular transformation. A nuclear protein termed Ki antigen with a relative mobility of 32,000 (Mr 32K) and which is recognized by SLE patient antisera has been identified in cells of human, bovine, and murine origin. Recently, cDNA clones for the bovine and human Ki antigens have been isolated using SLE patient antisera (T. Nikaido, et al., in preparation). The nucleotide sequence predicted a protein of 239 amino acids with a possible nuclear localization signal resembling that identified in SV40 T antigen and other nuclear proteins. Here we show that the expression of Ki antigen is regulated in the normal cell, but not in the transformed cell. Furthermore, in the K-ras temperature-sensitive mutant cell line, ts 371 normal rat kidney (NRK), Ki antigen expression increases several-fold at the permissive temperature relative to the nonpermissive temperature. These results suggest that expression of Ki antigen might be correlated with cellular transformation as well as with cell growth regulation.
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PMID:Loss in transformed cells of cell cycle regulation of expression of a nuclear protein recognized by SLE patient antisera. 254 Oct 6

Ki antigen from rabbit thymus extract was purified by ammonium sulfate precipitation, anti-Ki affinity chromatography, and high pressure liquid chromatography gel filtration. The purified Ki antigen gave a single polypeptide with an MW of 32,000 by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and it specifically reacted with anti-Ki antibody by immunoblotting. The isoelectric point of the Ki antigen was found by isoelectric focusing to be 4.3. An enzyme-linked immunosorbent assay using the purified Ki antigen was established, and the clinical significance of the anti-Ki antibody in systemic lupus erythematosus (SLE) was studied. Thirty of 140 patients with SLE (21.4%) had anti-Ki antibody by enzyme-linked immunosorbent assay, whereas 11 (7.9%) were positive by double immunodiffusion. Analysis of clinical and serologic data on patients with SLE suggested a higher prevalence of central nervous system involvement in patients with anti-Ki antibody.
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PMID:Purification and characterization of Ki antigen and detection of anti-Ki antibody by enzyme-linked immunosorbent assay in patients with systemic lupus erythematosus. 259 10

Abstract We studied the characteristics of anti-Ki antibodies that react with a synthetic peptide (KILT) which has homology with SV40 large T antigen nuclear localization signal (SV40 T NLS). Immunoreactivity of antibodies to KILT was tested by enzyme-linked immunosorbent assay (ELISA), and this reactivity was compared with results obtained by immunoblotting using purified Ki and ELISA using purified or recombinant Ki antigen. The clinical significance of anti-KILT antibodies in lupus patients was also studied. Twenty percent of anti-Ki sera reacted with KILT, and all sera that reacted with KILT recognized both purified and recombinant Ki antigen in all our assay systems. A significant correlation was observed between reactivities in ELISA using KILT and with these using purified and recombinant Ki. Some sera with low titers by double immunodiffusion (DID) reacted with KILT, whereas high-titer anti-Ki sera showed a tendency to react with Ki antigen in different assays. The prevalence of discoid rash and sicca complex was higher in the anti-KILT-positive group. The amino acid sequence homologous to SV40 T NLS is an immunologically active epitope on the Ki antigen; reactivity to this epitope is associated with characteristic clinical features allied with anti-Ki antibodies in lupus patients.
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PMID:Anti-Ki antibodies recognize an epitope homologous with SV40 nuclear localization signal: clinical significance and reactivities in various immunoassays. 2438 32