Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: 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)

Endogenous ecotropic type C viruses were induced by iodedeoxyuridine from nontransformed and chemically or spontaneously transformed clones of the C3H/10T1/2 cell line. Viruses produced by cells of certain transformed clones were N-tropic and formed large XC plaques. In contrast, viruses produced by nontransformed C3H/10T1/2 cells were not detectable in the XC plaque test. These XC- viruses infected mouse cells with high efficiency, as shown by the induction of murine leukemia virus group-specific antigens in infected cells, but virus production, as determined by DNA polymerase-containing particles, was extremely low. Upon growth in certain mouse cells these replication-deficient, XC(-) viruses converted to type C viruses that were similar in XC assays to N-tropic AKR virus (XC+).
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PMID:Endogenous ecotropic mouse type C viruses deficient in replication and production of XC plaques. 5 71

The stability of Rauscher leukemia virus (RLV) was investigated under certain laboratory conditions. The half life of the virus at 37 degrees was 7 hr, and considerably longer at lower temperatures. RNA dependent DNA polymerase activity was more stable than infectivity at all temperatures. Air dried virus had a half life of approximately 1 hr, but was rapidly inactivated by uv light or 70% alcohol.
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PMID:Stability of Rauscher leukemia virus under certain laboratory conditions. 6 90

Terminal deoxynucleotidyl transferase (TDT) is an unusual DNA polymerase that does not use template information to synthesize new strands of DNA. It is normally found in high concentration in thymus (50 u/10(8) cells) and in low concentration in bone marrow (less than 5 u/10(8)). We report TDT measurements in the marrow and/or peripheral blood of 51 adult patients, 28 of whom had leukaemia. TDT is present in very high levels (greater than 50 u/10(8) cells) in leukaemic lymphoblasts and in low levels in leukaemic myeloblasts (less than 9 u/10(8) cells). Of two patients who developed lymphosarcoma-cell leukaemia following treatment of poorly differentiated lymphocytic lymphoma, one had high and one low levels of TDT in the leukaemic blast cells. Leukaemic cells from three of seven patients with chronic myeloid leukaemia in blast crisis had TDT levels within the range expected of acute lymphoblastic rather than acute myeloid leukaemia. High TDT in leukaemic cells probably marks them as derivatives of lymphoid progenitor, thymic or pluripotential stem cells. Quantitative assay of TDT may provide information useful in classifying haematological neoplasms.
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PMID:Terminal deoxynucleotidyl transferase measurements in the differential diagnosis of adult leukaemias. 6 84

Rauscher murine leukemia virus was produced in roller-bottle cultures of chronically infected JLS-V9 cells. Virus from this culture fluid was concentrated and purified by two semi-isopycnic bandings in sucrose gradients. Virus material obtained from young, nonconfluent cultures (early-harvest virus) yielded products characteristically containing endogenous ribonucleic acid-dependent deoxyribonucleic acid polymerase with high specific activity (400 to 1,000 pmol of [3H]thymidine 5'-triphosphate incorporated per milligram of protein per hour). Fluids obtained from older confluent cultures (late-harvest virus) yielded products with endogenous ribonucleic acid-dependent deoxyribonucleic acid polymerase with little or no specific activity (200 pmol or less of [3H]thymidine 5'-triphosphate incorporated per milligram of protein per hour), but with higher virus particle counts and greater amounts of protein and gs antigen than the early-harvest products.
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PMID:Method for reproducible large-volume production and purification of Rauscher murine leukemia virus. 6 67

An RNA directed DNA polymerase was purified over 2500 fold from gibbon ape leukemia virus by successive column chromatography on Sephadex G100, DEAE cellulose, phosphocellulose and hydroxyapatite. The purified DNA polymerase has a molecular weight of 68 000, a pH optimum of 7.5, a Mn2+ optimum of 0.8 mM, and KCl optimum of 80 mM. The purified enzyme transcribes heteropolymeric regions of viral 60-70 S RNA isolated from avian myeloblastosis virus, Rauscher murine leukemia virus and simian sarcoma virus and it is inhibited by antiserum prepared against either gibbon ape leukemia virus or simian sarcoma virus DNA polymerases.
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PMID:Purification and characterization of gibbon ape leukemia virus DNA polymerase. 6 92

Rauscher leukemia virus RNA-directed DNA polymerase has been purified to near homogeneity (greater than 90% pure) using affinity chromatography on polycytidylate-agarose with over 85% recovery of input enzymatic activity. The purified enzyme has a molecular weight of approximately 70,000 and appears to consist of a single polypeptide chain. The enzyme is free of DNase, but has RNase H activity. Analysis of the requirements for optimal rates of DNA synthesis by this enzyme using synthetic and natural template-primers has revealed template-specific variations in such requirements. During these studies it was observed that DNA synthesis catalyzed by Rauscher leukemia virus DNA polymerase is inhibited by the addition of inorganic phosphate. An analysis of the mechanism of phosphate inhibition was carried out using the synthetic template-primer poly(A)-(dT)10. It appears that by some mechanism, possibly involving the substrate binding site of the enzyme, phosphate ions inhibit DNA synthesis with a more acute effect on the rate of chain growth than on that of initiation. The extension of these studies to DNA synthesis catalyzed by a variety of mammalian type C viral reverse transcriptases revealed that low levels ( less than or equal to 2 mM) of inorganic phosphate strongly inhibited DNA synthesis. The susceptibility to phosphate inhibition appears unique to mammalian type C viral enzymes since the type B viral enzyme, Escherichia coli DNA polymerase I, avian myeloblastosis virus and Mason Pfizer monkey tumor virus reverse transcriptase and cellular DNA polymerases alpha and gamma are not inhibited by inorganic phosphate. This phenomenon of phosphate inhibition of various DNA polymerases, therefore, provides a new basis for the differentiation of the sources and nature of these enzymes.
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PMID:Purification and properties of Rauscher leukemia virus DNA polymerase and selective inhibition of mammalian viral reverse transcriptase by inorganic phosphate. 6 68

The activities of streptovaricin complexes, streptovaricins, streptovals, and streptovarinic degradation products were elevated against RNA-directed DNA polymerases of Rauscher leukemia virus, DNA-dependent DNA polymerase of bacterial and mammalian cells, and DNA-dependent RNA polymerases of mammalian origin. The activities of streptovaricins were also listed for comparison purposes. The effects of streptovaricin complexes on viral DNA polymerases varied significantly from lot to lot, and streptovaricin complex lot 7 was the most active. All the streptovals and streptovaricin degradation products except varicinal A showed a marked improvement (twofold to tenfold) in activity against the viral enzyme over the parent streptovaricins. None of these compounds, however, displayed any significant effect on either the DNA polymerase of L1210 leukemia cells and Escherichia coli or the RNA polymerase of isolated nuclei of mouse liver. As a result of tests in these systems, some specific inhibitors of RNA-directed DNA polymerases of Rauscher leukemia virus were selected.
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PMID:Effects of streptovaricins and their degradation products on RNA-directed DNA polymerase of Rauscher leukemia virus. 6 15

An antigen crossreacting with the 30,000-molecular-weight protein (p30) of the feline endogenous oncornavirus (RD114) was detected in a well-characterized human fibrosarcoma cell line, HT1080, by indirect immunofluorescence. Three antisera against RD114 p30 gave similar positive results, while two antisera prepared against simian sarcoma virus p30, one antiserum prepared against murine leukemia virus p30, and one antiserum prepared against feline leukemia virus p30 gave no immunofluorescence. The reactivity observed with the antiserum against RD114 p30 was detected in 10-40% of the cells at early passages and was no longer expressed by the forty-first subculture. The reactivity could be removed by adsorption of the antiserum with RD114-infected dog or human cells, but not by uninfected cells or by cells infected with an antigenically unrelated oncornavirus, feline leukemia virus. Neither complete virus particles nor reverse transcriptase (RNA-dependent DNA nucleotidyltransferase) activity was detected in the culture. These experiments suggest that the fibrosarcoma cell line is expressing an antigen related to the p30 protein of RD114 baboon endogenous virus group of oncornaviruses without producing complete virions.
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PMID:Expression of antigenic crossreactivity to RD114 p 30 protein in a human fibrosarcoma cell line. 6 79

The RNase H activity associated with several RNA-directed DNA polymerases is inhibited by the addition of DNA, in contrast to RNase H activity from enzymes devoid of polymerizing activity. Kinetic investigations of the inhibitory effect of DNA, using purified Rauscher leukemia virus DNA polymerase as a test enzyme, revealed that the addition of DNA to an ongoing RNase H reaction causes an immediate cessation of RNase H activity. Concomitant initiation of DNA synthesis by inhibitory DNA can occur, provided that appropriate substrate and primer is available. Thus, in addition to providing a simple test for the distinction between polymerase-associated and polymerase-independent RNase H activity, this study strongly supports the concepts that (i) RNase H activity expressed by several mammalian oncoviral reverse transcriptases is an integral part of that molecule, and (ii) that the catalytic site of RNase H activity is also involuved in template-primer binding.
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PMID:Specific inhibition of DNA polymerase-associated RNase H by DNA. 6 22

Northern poke lymphosarcoma DNA polymerase was partially purified from particulate fractions banding at 1.15 to 1.16 g/ml from homogenates prepared from frozen necropsies of tumor-bearing pike. The enzyme behaves as a typical reverse transcriptase, in that it prefers ribotemplates to deoxytemplates. The isoelectric point (pl 5.5) is similar to that of avian myeloblastosis virus polymerase. The pike enzyme elutes from a phosphocellulose column at 0.22 M potassium phosphate, the same as avian myeloblastosis virus DNA polymerase. The enzyme activity is inhibited by pyran, a specific inhibitor of viral DNA polymerases. The most striking difference between the pike lymphoma polymerase and the other viral DNA polymerases tested is the low maximum temperature of 20 degrees, compared to 30 degrees for Rauscher leukemia virus polymerase and 38 degrees for avian myeloblastosis virus and Rous sarcoma virus.
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PMID:Presence of DNA polymerase in lymphosarcoma in northern pike (Esox lucius). 6 92


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