RNA-dependent DNA polymerase of an endogenous type C virus of mice: purification and partial characterization.
An RNA-dependent DNA polymerase was isolated from purified virions of endogenous oncornaviruses released by the MOPC-315 murine myeloma cell line. Upon sodium dodecyl sulfate-polyacrylamide gel electrophoresis, the purified enzyme was found to consist of two major polypeptides with molecular weights of about 28,000 and 26,500. The active enzyme had a molecular weight of approximately 56,000, as calculated from its sedimentation on glycerol density gradients, indicating that it is probably a dimer of the two subunit polypeptides. The isolated MOPC-315 virus polymerase exhibited all three activities known to be found in the DNA polymerase from oncornaviruses, namely, an RNA-dependent DNA polymerase, a DNA-dependent DNA polymerase, and an RNase H. The RNA-dependent polymerase activity showed a prounced preference for Mn2+ over Mg2+, whereas the DNA-dependent and RNase H reactions were catalyzed by these two cations to an almost equal extent. The purified polymerase was found to be immunologically related to the polymerase of Rauscher murine leukemia virus.
D000818:Animals; D000956:Antigens, Viral / Q000032:analysis; D004259:DNA-Directed DNA Polymerase / Q000378:metabolism; D008274:Magnesium / Q000494:pharmacology; D008345:Manganese / Q000494:pharmacology; D051379:Mice; D008970:Molecular Weight; D012194:RNA-Directed DNA Polymerase / Q000276:immunology / Q000302:isolation & purification* / Q000378:metabolism; D012190:Retroviridae / Q000201:enzymology*; D012260:Ribonucleases / Q000378:metabolism; D013379:Substrate Specificity
D000956:Antigens, Viral; D008345:Manganese; D012194:RNA-Directed DNA Polymerase; D004259:DNA-Directed DNA Polymerase; D012260:Ribonucleases; D008274:Magnesium