Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P62988 (Ubiquitin)
 4,326 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A human erythroleukemia cell line, K-562 T1, was adapted to a protein-free chemically defined medium; that is, the medium does not contain any proteins such as exogenous hormones, growth factors, serum and serum albumin. The K-562 T1 cells which can proliferate in a protein-free medium are one of the model systems suitably supporting the autocrine hypothesis, which claims that cancer cells produce and respond to their own growth factors. The K-562 T1 cells were cultured in a protein-free medium at large scale and the growth factors were purified from the conditioned medium. It was found that K-562 T1 cells produce at least two growth factors; one is LGF-I (leukemia-derived growth factor-I) which can stimulate the proliferation of a wide range of human leukemia cell lines and the other is LGF-II (leukemia-derived growth factor-II), which can contribute to the growth of fibroblasts. LGF-I was purified using QAE-Sephadex, Bio Gel P-60 and Mono S FPLC. The purified protein was found to be homogenous by SDS-polyacrylamide gel electrophoresis and NH2-terminal sequence analysis. The molecular weight of LGF-I was 20,000 by SDS-polyacrylamide gel electrophoresis. The 30 NH2-terminal residues of LGF-I are the same as that of ubiquitin. Ubiquitin is a protein found in eukaryotic cells with molecular weight of 8,600. In the nucleus ubiquitin is conjugated to histone 2A to form the nuclear protein A24 which may play a role in regulation of chromatin structure, and in the cytoplasm is part of an ATP-dependent non-lysosomal proteolytic pathway. However, its physiological significance has not yet been fully resolved. Ubiquitin purified from bovine thymus did not show cell proliferating activity for any cells tested. The results suggest that LGF-I is a new autocrine growth factor with a molecular weight of 20,000 daltons, containing ubiquitin at the NH2-terminal end.
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PMID:N-terminal amino acid sequence of leukemia derived growth factor (LGF) from human erythroleukemia cell culture. 303 91

Ubiquitin (Ub) plays a crucial role in almost every aspect of cellular functions. It is encoded by four genes, of which UbC is known to meet cell demand for ubiquitin in both basal and stressful conditions. To understand the molecular mechanisms regulating UbC gene expression, we performed a functional characterization of the UbC promoter. Deletion analyses on the 5' end of the -916/+878 promoter region, excluded the functional importance of nt -916/-371 in the transcriptional regulation of the gene, while 3' deletions revealed that intron removal (nt+65/+876) resulted in a marked reduction of promoter activity in all the reporter constructs, regardless of the cell types. Intron substitution with a heterologous chimeric intron failed to restore promoter activity, thus allowing to exclude that the splicing event, per se, can be responsible for the intron-mediated burst of transcription. Gel shift assays demonstrated nuclear factor binding with the +137/+766 intron region. Reporter constructs carrying partial intron deletions confirmed that this sequence is, indeed, required for maximal transcriptional activity. Computer-based analysis found potential Sp1 binding motifs within the intron sequence and electrophoretic mobility shift and supershift assays demonstrated that both Sp1 and Sp3 transcription factors interact, in vitro, with the UbC intron, at multiple binding sites. Moreover, ectopic expression of Sp1 and Sp3 revealed that both transcription factors positively regulate UbC promoter activity. Collectively, our data highlight the very new evidence that the 5'-UTR intron is crucial in regulating UbC gene expression and provide insights into the pivotal role of Sp1/Sp3 binding to the intronic enhancer in the regulation of UbC transcription.
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PMID:A potent enhancer element in the 5'-UTR intron is crucial for transcriptional regulation of the human ubiquitin C gene. 1973 23

Ubiquitin - proteasome system (UPS), the major protein degradation pathway in the cells, typically degrades short - lived and damaged proteins and regulates growth and stress responses. This pathway is altered in various cancers, including Acute Lymphoblastic Leukemia (ALL). ALL begins with a change in bone marrow cells and is the most common type of leukemia in children under 15 years. UBE2Q1 as a new characterized gene of E2 enzyme family is located on chromosome 1 and reported to be altered in some malignancies. In this study, we aimed to explore the expression pattern of UBE2Q1 gene in children with ALL. For this purpose, a series of RT - PCR and quantitative RT - PCR were performed on a collection of 20 bone marrow samples of ALL patients and the same number of whole blood samples of age - matched normal subjects. Gel electrophoresis of RT - PCR products revealed the expression of UBE2Q1 mRNA in most of the normal (90%) and about half of the leukemic (45%) samples. QRT - PCR data indicated that only 1 patient out of 20 (5%) showed up regulation of the gene (> 2 folds). In 4 patients (20%), the expression of UBE2Q1 mRNA was equivocal (from 1/2 to 2) and in 15 cases (75%), the gene was down regulated (> 1/2) when compared to the normal samples. In conclusion, down regulation of UBE2Q1 in the majority of the leukemic samples suggests its potential implication in the pathogenesis of ALL. UBE2Q1 can be considered as a molecular marker and a candidate targeting to treat ALL in the future.
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PMID:UBE2Q1, as a Down Regulated Gene in Pediatric Acute Lymphoblastic Leukemia. 2503 59