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Lack of Serological Relationship Among DNA Polymerases of Avian Leukosis-Sarcoma Viruses, Reticuloendotheliosis Viruses, and Chicken Cells 总被引:32,自引:27,他引:5
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Antibodies against a large and a small DNA polymerase isolated from chicken embryos and against avian myeloblastosis virus DNA polymerase were used to study the serological relationships of the DNA polymerase activities of three avian systems with RNA and a DNA polymerase-avian leukosis-sarcoma viruses, reticuloendotheliosis viruses, and a fraction from uninfected chicken cells. The DNA polymerase activity of disrupted virions of all avian leukosis-sarcoma viruses tested was neutralized to the same extent by antibody against avian myeloblastosis virus DNA polymerase and was not neutralized by the antibodies against chicken cellular DNA polymerases. The viruses tested included induced leukosis viruses and Rous-associated virus-O. The DNA polymerase activity of disrupted virions of all of the reticuloendotheliosis viruses was not neutralized by any of the antibodies. The chicken endogenous RNA-directed DNA polymerase activity was neutralized partially or completely, in different experiments, by antibody against the small DNA polymerase isolated from chicken embryos, but was not neutralized by the other two antibodies. 相似文献
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Sequence relatedness between the subunits of avian myeloblastosis virus reverse transcriptase. 总被引:9,自引:0,他引:9
One- and two-diminsional tryptic and chymotryptic peptide maps of 125-I-labeled alpha and alphabeta avian myeloblastosis virus DNA polymerase demonstrate that the alpha polypeptide of the one and two subunit enzymes are structurally similar, if not identical. Furthermore, the beta subunit contains the same major 125I-labeled peptides as alpha, plus several additional peptides. These relationships and the fact that aging of purified alphabeta avian myeloblastosis virus DNA polymerase increases the proportion of alpha DNA polymerase that can be isolated from the alphabeta enzyme by phosphocellulose chromatography, suggests that alpha is derived from beta by proteolytic cleavage. 相似文献
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Activation of an Mg2+-dependent DNA endonuclease of avian myeloblastosis virus alpha beta DNA polymerase by in vitro proteolytic cleavage. 总被引:14,自引:12,他引:2
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Partial chymotryptic digestion of purified avian myeloblastosis virus alpha beta DNA polymerase resulted in the activation of a Mg2+-dependent DNA endonuclease activity. Incubation of the polymerase-protease mixture in the presence of super-coiled DNA and Mg2+ permitted detection of the cleaved polymerase fragment possessing DNA nicking activity. Protease digestion conditions were established permitting selective cleavage of beta to alpha, which contained DNA polymerase and RNase H activity and to a family of polypeptides ranging in size from 30,000 to 34,000 daltons. These latter beta-unique fragments were purified by polyuridylate-Sepharose 4B chromatography and were shown to contain both DNA binding and DNA endonuclease activities. We have demonstrated that this group of polymerase fragments derived by chymotryptic digestion of alpha beta DNA polymerase is similar to the in vivo-isolated avian myeloblastosis virus p32pol in size, sequence, and DNA endonuclease activity. 相似文献
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RNA-Dependent DNA Polymerase Activity of RNA Tumor Viruses II. Directing Influence of RNA in the Reaction 总被引:30,自引:16,他引:14
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The role of ribonucleic acid (RNA) in deoxyribonucleic acid (DNA) synthesis with the purified DNA polymerase from the avian myeloblastosis virus has been studied. The polymerase catalyzes the synthesis of DNA in the presence of four deoxynucleoside triphosphates, Mg(2+), and a variety of RNA templates including those isolated from avian myeloblastosis, Rous sarcoma, and Rauscher leukemia viruses; phages f2, MS2, and Qbeta; and synthetic homopolymers such as polyadenylate.polyuridylic acid. The enzyme does not initiate the synthesis of new chains but incorporates deoxynucleotides at 3' hydroxyl ends of primer strands. The product is an RNA.DNA hybrid in which the two polynucleotide components are covalently linked. Free DNA has not been detected among the products formed with the purified enzyme in vitro. The DNA synthesized with avian myeloblastosis virus RNA after alkaline hydrolysis has a sedimentation coefficient of 6 to 7S. 相似文献
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Purification of Avian Myeloblastosis Virus DNA Polymerase by Affinity Chromatography on Polycytidylate-Agarose 总被引:9,自引:5,他引:4
Polycytidylic acid [poly(rC)] covalently linked to cyanogen bromide-activated agarose is an effective affinity matrix for the RNA-dependent DNA polymerase from avian myeloblastosis virus. Poly(rC)-agarose is capable of binding large quantities of avian myeloblastosis DNA polymerase, which is then eluted by using a linear KCl gradient of increasing concentration. The DNA polymerase isolated from crude, detergent-disrupted virions by a single pass through columns of poly(rC)-agarose appears nearly homogeneous (approximately 90% pure) as determined by sodium dodecyl sulfate-polyacrylamide disc gel electrophoresis. Complete recovery of input enzymatic activity was obtained. Results suggest that polyribonucleotide columns may provide a high-yield, rapid method for the purification of oncornaviral DNA polymerase. 相似文献
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Radioimmunological comparison of the DNA polymerases of avian retroviruses. 总被引:6,自引:4,他引:2
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125I-labeled DNA polymerases of avian myeloblastosis virus and spleen necrosis virus were used in a radioimmunological characterization of avian retrovirus DNA polymerases. It was shown that avian leukosis virus and reticuloendotheliosis virus DNA polymerases do not cross-react in radioimmunoassays. Within the avian leukosis virus species, species-specific and type-specific antigenic determinants of the DNA polymerase were defined. The previous finding of genus-specific antigenic determinants in avian myeloblastosis virus and Amherst pheasant virus DNA polymerases was confirmed and extended to members of all subgroups of avian leukosis virus. It was shown that there is little immunological variation between the DNA polymerases of the four members of the reticuloendotheliosis virus species. Particles with RNA-dependent DNA polymerase activity from the allantoic fluid of normal chicken eggs and from the medium of a goose cell culture did not compete for the antibodies directed against any of the sets of antigenic determinants defined in this study. 相似文献