Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.7.7 (DNA polymerase)
 17,007 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Nuclear extracts, prepared from Autographa californica nuclear polyhedrosis virus-infected Spodoptera frugiperda cells during a time course of infection, were analyzed for activation of early gene transcription and for late gene transcription. The templates used in the in vitro transcription assays contained promoters for baculovirus genes that have been classified as immediate early, delayed early, and late. The promoters were derived from the baculovirus 39K, p26, gp64, and DNA polymerase genes. In addition, the adenovirus major late promoter was included in these studies. We found that transcription from promoters classified as immediate early or delayed early was accurately initiated by using extracts from uninfected cells. Furthermore, transcription from all early promoters tested was found to be transactivated by nuclear extracts prepared at 4 and 8 h postinfection. However, baculovirus enhancer-dependent transcriptional activation was not observed in tests with templates containing the hr5 enhancer sequence. Transcription from baculovirus late promoters was also not observed. A decline in transcription by nuclear extracts prepared from cells late in infection was associated with the presence of DNase activity.
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PMID:In vitro transactivation of baculovirus early genes by nuclear extracts from Autographa californica nuclear polyhedrosis virus-infected Spodoptera frugiperda cells. 131 63

The BCL-2 (B-cell lymphoma/leukemia-2) gene is frequently involved in t(14;18) translocations in non-Hodgkin's lymphomas and encodes a 26-kDa intracellular, membrane-associated protein. Expression of the BCL-2 gene has previously been correlated with cellular proliferation in normal and neoplastic lymphoid cells under a variety of experimental conditions. To examine the regulation of p26-BCL-2 protein levels during the cell cycle, we utilized the method of counterflow centrifugal elutriation to enrich for cells in various phases of the cell cycle. Relative levels of p26-BCL-2 protein were measured by immunoblotting, and comparisons were made with a cell cycle-regulated protein, p62-CYCLIN-A, and a protein whose levels are constant throughout the cell cycle, p36-PCNA (DNA polymerase-delta auxiliary factor). Relative levels of p26-BCL-2 and p36-PCNA did not vary among cell fractions enriched for specific phases of the cell cycle, whereas p62-CYCLIN-A was elevated in late S- and G2/M-phase cells. Similar results were obtained with lymphoma and leukemia cell lines that have either normal or translocated BCL-2 genes. These results obtained by elutriation were confirmed by pharmacologically inducing cell cycle arrest in proliferating lymphoid cell lines with hydroxyurea, quercetin, and nocodazole which blocked cells at S, G2, and M phases, respectively. Taken together, the data indicate that p26-BCL-2 is not a true cell cycle-regulated protein, although its levels can fluctuate in connection with changes in rates of cellular proliferation under some circumstances.
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PMID:Cell cycle analysis of p26-BCL-2 protein levels in proliferating lymphoma and leukemia cell lines. 158 93

Previous studies in our laboratory used a papillation assay to identify a set of mutations in the E. coli dnaE gene that confer increased accuracy of DNA replication (antimutators). These antimutators were isolated as suppressors of the hugh mutability of a mismatch-repair-defective mutL strain, in which the majority of mutations represent uncorrected replication errors (mainly A.T --> G.C and G.C --> A.T transitions). In the present study, we have sought suppressors of the high mutability of a mutT mutator strain. mutT strains produce a high frequency of A.T --> C.G transversions due to their lack of the mutT-encoded 8-oxo-dGTPase, leading to a high frequency of A.(8-oxoG) mispairing errors. Following localized mutagenesis of the dnaE-dnaQ region of the chromosome, two strong suppressors of mutT mutability were obtained, both residing in the dnaE gene (dnaE940 and dnaE941). When subsequently tested in a mutL strain, these two alleles also proved antimutators in this background, dnaE941 being significantly stronger than the previously isolated antimutators. The results suggest that the DNA polymerase may use similar mechanisms to discriminate against A.(8-oxoG) transversion mispairs and A.C or T.G transition mispairs. The finding may also have significance for teh interpretation of the antimutator effect conferred by these dnaE alleles in a wild-type (mut+) background.
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PMID:Suppressors of Escherichia coli mutT: antimutators for DNA replication errors. 865 78

The genomic DNA of Helicoverpa armigera single-nucleocapsid nucleopolyhedrovirus (C1 clone) was digested with BamHI, EcoRV, HindIII, KpnI, PstI and XbaI, respectively, and formed 11, 31, 13, 6, 7, and 25 fragments larger than 400 bp, respectively. The size of genome was estimated to be about 130.7 kb. A detailed physical map was constructed for the six restriction enzymes. The five homologous region, hr1, hr2, hr3, hr4 and hr5, and the ten genes including polyhedrin gene (ph), immediate-early gene(ie1), p74, p10, chitinase gene, DNA directed DNA polymerase gene (DNApol), helicase gene, superoxide dismutase gene (sod), alkaline-exonuclease gene (alk-exo), ecdysteroid UDP-glucosyltransferase gene (egt) were identified and their locations in the genome were determined. The genome organization of HaSNPV is quite different from those of other NPVs ever determined. The p10 gene was located in the fragment BamHI-I(1.89 kb) with the transcriptional direction opposite to the polyhedrin gene. Upstream and downstream of the p10 gene were p26 and p74 gene, respectively. The transcriptional direction of p26 is the same as that of p10 gene, and opposite to that of the p74 gene. The ORF encoding p10 was 261 nucleotide long and encoding a putative 87 amino acid polypeptide of 9.3 kD. The immediate upsteam region of the p10 was an A-rich region, and aconserved TAAG motif, associated with transcriptional start sites in other p10 genes, was identified at a site 52 nucleotides upstream of the start codon ATG. A putative polyadenylation signal, AATAAA, was found 20 nucleotides downstream of the termination codon.
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PMID:Genome Structure and the p10 Gene of the Helicoverpa armigera Nucleopolyhedrovirus. 1205 Aug 7

In situ, oxidation of deoxyguanosine yields 8-hydroxy-2'-deoxyguanosine (8-oxo-dG), which is mutation prone and results in a G:C --> T:A transversion following DNA replication. Another pathway to the formation of DNA containing 8-oxo-dG is by the misincorporation of 8-oxo-dGTP via DNA polymerase. Human MutT homologue (hMTH1), an 8-oxo-dGTPase, prevents misincorporation of this oxidized nucleotide by hydrolyzing 8-oxo-dGTP to 8-oxo-dGMP. Previous studies have shown that hMTH1 mRNA is overexpressed in human renal cell carcinomas and breast tumors. Elevated levels of hMTH1 protein have also been detected in brain tumors. In the current study, we determined whether hMTH1 protein is overexpressed in primary non-small-cell lung carcinomas as compared to adjacent histologically normal lung tissue. Twenty matched human lung tumor/normal pairs were examined by Western analysis for expression of hMTH1 protein. Overexpression in the tumors was detected in 4/8 (50%) adenocarcinomas, 4/4 (100%) adenocarcinomas with bronchioalveolar (BAC) features, 2/2 (100%) BACs, and 3/6 (50%) squamous cell carcinomas. The data from Western analysis were validated by immunohistochemical staining for hMTH1 protein. The results of this study indicate that hMTH1 protein may be a potential marker for the detection of persistent oxidative stress in lung cancer.
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PMID:Expression of human MutT homologue (hMTH1) protein in primary non-small-cell lung carcinomas and histologically normal surrounding tissue. 1275 55