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)

Guinea pig embryo (GEP) cells were transformed in vitro by the Kirsten strain of mouse sarcoma virus (Ki-MSV). The transformed cells were found to release infectious virus continuously and produced high titers of group-specific (gs) complement-fixing (CF) antigen characteristics of the murine sarcoma-leukemia virus complex. Foci of transformed cells were similar in appearance to those obtained with Ki-MSV in mouse and rat cells. The transformed cells produced RNA dependent DNA polymerase and type C virus particles with a density of approximately 1.15 g/ml in sucrose gradients by 3H-uridine labeling. The transformed cells produced tumors when transplanted into newborn guinea pigs. A number of focus-derived clonal lines from Ki-MSV transformed cells were isolated and characterized. All the focus-derived lines were found to be either producers or nonproducers (NP). The NP guinea pig cells produced neither infectious virus nor viral antigens of the murine sarcoma-leukemia virus complex although they were morphologically indistinguishable from virus-releasing MSV transformed GPE lines and produced tumors when transplanted into newborn guinea pigs. However, the sarcoma virus genome could be rescued in these NP cells by cocultivation with "helper" murine leukemia virus (MuLV) releasing GPE cells. Particles resembling guinea pig leukemia virus were activated from guinea pig NP cells or cultured normal guinea pig cells following chemical treatment. These particles were approximately 100 nm in the mature form and had a density of 1.16-1.17 g/ml. They contained RNA dependent DNA polymerase activity.
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PMID:Characterization of murine sarcoma virus transformation of guinea pig cells and activation of an RNA tumor-like virus from nonproducer guinea pig cells. 5 21

Two forms of DNA polymerase are present in RD-114-infected human, dog, and mink cells, but are not detectable in uninfected cells. The two enzymes are indistinguishable catalytically and immunologically, but differ with respect to molecular weight and elution position from (dT)12-18-cellulose and phosphocellulose. The large enzyme (equivalent 95,000 daltons) is found in the infected cells, but not the virions produced by these cells. The virions contain only the smaller enzyme (equivalent 70,000 daltons). The larger form may represent a mammalian viral equivalent to the beta subunit of avian RNA tumor virus DNA polymerase.
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PMID:Two active forms of RD-114 virus DNA polymerase in infected cells. 5 89

The ribonucleic acid-dependent deoxyribonucleic acid polymerase assay was used to detect type-C viruses in live virus vaccines. Conditions were first established to maximize the sensitivity of the assay. Vaccines tested included live poliomyelitis, rubella, measles, mumps, and yellow fever. Only yellow fever and measles vaccines known to have been produced in avian leukosis-contaminated cells showed evidence of type-C viruses using the assay. The result of the survey show that the assay has direct practical application to the problem of detecting latent agents in biological products intended for human use.
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PMID:Screen for type-C ribonucleic acid viruses in vaccines using the ribonucleic acid-dependent deoxyribonucleic acid polymerase assay. 5 57

The biophysical and biochemical properties of the virus particles released by guinea pig embryo cells treated with 5-bromo-2'-deoxyuridine (BUdR) have been compared to those of the B-type mouse mammary tumor virus (MMTV) and the C-type Rauscher murine leukemia virus. The high-molecular-weight (60 to 70S) RNA of the BUdR-induced guinea pig virus (GPV) has a molecular weight of 8 X 106 when measred by mixed agarose polyacylamide gel electrophoresis. The virus particles isolated from the tissue culture medium of BUdR-induced guniea pig cells have the following properties in common with MMTV: (i) a buoyant density of 1.18 g/ml in sucrose and 1.21 g/ml in CsCl, and (ii) a DNA polymerase that prefers Mg2+ over Mn2+ in an assay using the synthetic template poly(rC):oligo(dG). No nucleic acid sequence homology between GPV RNA and the viral RNAs of the MMTV, murine leukemia virus, hamster sarcoma virus, or Mason-Pfizer monkey virus could be observed in a competition hybridization assay using the radioactive-labeled GPV 60 to 70S RNA. By this same competition by hybridization assay the frequency of GPV proviral sequences was estimated to be at least 83 per haploid cellular genome of guniea pig cells. No nucleic acid sequences related to be GPV RNA were detected in the DNA of normal tissues of mice, rats, cats, dogs, baboons, or humans by direct RNA-DNA hybridization using radioactive GPV60 to 70S RNA.
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PMID:Biochemical properties of the bromodeoxyuridine-induced guinea pig virus. 5 33

DNA polymerase was purified to apparent electrophoretic homogeneity from virions of spleen necrosis virus (SNV). (SNV is a member of the reticuloendotheliosis group of avian ribodeoxyviruses). The SNV DNA polymerase appears to consist of a single polypeptide with a molecular weight of 68,000. The SNV DNA polymerase has a preference for Mn2+ for DNA synthesis with an RNA template and Mg2+ for DNA synthesis with a deoxyribohomopolymer template. At the optimum concentrations of divalent cation, the relative rates of DNA synthesis by SNV DNA polymerase with different template.primers were similar to the relative rates of DNA synthesis by an avian leukosis virus DNA polymerase, with the exception of a lower relative rate of DNA synthesis by SNV DNA polymerase with SNV RNA. However, in contrast to DNA synthesized by the avian leukosis virus DNA polymerase with a SNV RNA template, DNA synthesized by SNV DNA polymerase with an SNV RNA template did not hybridize to the SNV RNA. SNV DNA polymerase has RNase H activity which is antigenically distinct from the RNase H activity of avian leukosis-sarcoma virus DNA polymerase.
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PMID:Purification and properties of spleen necrosis virus DNA polymerase. 5 34

Reticuloendotheliosis virus (REV) contains an endogenously instructed, RNA-directed DNA polymerase activity. Both the endogenous and exogenous DNA polymerase activities exhibited up to 10-fold greater activity at the optimum concentration of manganous ion (0.025 mM for exogenous; 0.25 mM for endogenous) than at any concentration of magnesium ion. Antiserum to the DNA polymerase of an REV group virus (spleen necrosis virus) inhibited both endogenous and exogenous DNA polymerase activity of REV, whereas antiserum to the Rous sarcoma virus (Rous-associated virus-0) [RSV(RAV-0)]DNA polymerase did not. The DNA product of the endogenous reaction is associated with the high-molecular-weight RNA of REV and anneals with REV RNA but not with RNA from Rous sarcoma virus.
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PMID:RNA-directed DNA polymerase activity of reticuloendotheliosis virus: characterization of the endogenous and exogenous reactions. 5 35

Reticuloendotheliosis viruses (REV) contain an endogenous RNA-directed DNA polymerase activity. The endogenous DNA polymerase activity can be elicited in purified preparations of REV by treatment with nonionic detergents. The enzyme activity has a strong preference for manganous ions. Therefore, appreciable endogenous DNA polymerase activity can be demonstrated only if the reaction mixture contains appropriate concentrations of manganous ions. Enzyme activity can be inhibited by pretreatment with RNase or deletion of one or more deoxyribonucleoside triphosphates from the reaction mixture. In contrast, actinomycin D has little effect in initial DNA synthesis. The results from both velocity and equilibrium centrifugation indicate that the nascent chains of product DNA are associated with 60S viral RNA. The DNA product of the endogenous DNA polymerase reaction is hybridizable to REV RNA, but not to avian leukosis virus RNA.
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PMID:Characterization of endogenous RNA-directed DNA polymerase activity of reticuloendotheliosis viruses. 5 36

Intracisternal A particle preparations from a murine neuroblastoma cell line (N18) and from a mineral oil-induced murine plasmacytoma (MOPC-104E) contain both an endogenous RNA-dependent DNA polymerase activity and high molecular-weight polyadenylic acid (poly[A])-containing RNA. The DNA polymerase activity is stimulated by oligo(dG)-poly(C) and oligo(dT)-poly(A) and to a lesser extent by oligo(dT)-poly(dA), in agreement with previous reports. The high-molecular-weight RNA is predominantly 35S and contains a poly(A) tract of approximately 220 nucleotides as judged by polyacrylamide gel electrophoresis. Small amounts of 70S RNA are also present. This RNA preparation contains RNA homologous to RNA from type-C particles, as judged by molecular hybridization experiments. However, since this RNA derives only in part from A-particles and in part from other cellular RNA, hybridization of A-particle endogenously synthesized DNA or reverse transcripts of A-particle RNA to purified type C viral 70S RNA may more accurately reflect the relationship of A-particle RNA to RNA from C-particles. None of these DNA transcripts hybridizes significantly to C-particle 70S RNA, although MOPC and N18 DNA transcripts share significant homology. Our interpretation of these results is that murine intracisternal A particles are not closely related genetically to the tested murine type C viruses, although an alternate possibility is that all the A-particle DNA transcripts are copied from only a small part of the genome, which is unrelated to C-particle RNA.
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PMID:Murine intracisternal type A particles: a biochemical characterization. 5 37

The ability of tryptophan tRNA (tRNATrp) to initiate reverse transcription of the 70S RNA of avian RNA tumor viruses suggested that the reverse transcriptase (RNA-dependent DNA polymerase; deoxynucleosidetriphosphate: DNA deoxynucleotidyltransferase; EC 2.7.7.7) might have a specific binding site for the tRNA. A complex of tRNATrp and the avian myeloblastosis virus reverse transcriptase has been demonstrated using chromatography on Sephadex G-100 columns. Of all the chicken tRNAs, only tRNATrp and a tRNA4Met bind to the enzyme with high enough affinity to be selected from a mixture of the chicken cell tRNAs. The ability of tRNATrp to change the sedimentation rate of the enzyme indicates that tRNATrp is not binding to a contaminant in the enzyme preparation. Treatment of the enzyme with monospecific antibody to reverse transcriptase prevented binding of tRNA as well as inhibited the DNA polymerase activity of the enzyme. The ability of reverse transcriptase to utilize tRNATrp aa a primer for DNA synthesis, therefore, appears to involve a highly specific site on the enzyme.
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PMID:Specific binding of tryptophan transfer RNA to avian myeloblastosis virus RNA-dependent DNA polymerase (reverse transcriptase). 5 56

A fibroblast-like cell culture was established from a stomach biopsy of a patient with metastatic adenocarcinoma. One of the cultures, at the 6th passage level, left unattended for a month at 37 degrees, produced numerous foci of epithelioid cells. Upon subculturing, an epithelioid cell line, designated HCCL (human carcinoma cell line), was established. The HCCL cells released particles possessing the characteristics of oncornaviruses: density 1.175 g/ml, cores with a density of 1.22-1.26 g/ml, high-molecular-weight RNA (60-70S) and RNA-instructed DNA polymerase activity (deoxynucleosidetriphosphate:DNA deoxynucleotidyltransferase, EC 2.7.7.7). Inoculation of particles released from HCCL cells into cultures of human embryo muscle fibroblasts resulted in the appearance of foci of transformed cells.
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PMID:Transformation of cultured human embryonic fibroblasts by oncornavirus-like particles released from a human carcinoma cell line. 5 57


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