title: Characterization of an RNA-directed DNA polymerase found in association with murine intracytoplasmic A-particles.
abstract: An RNA-directed DNA polymerase was found to be associated with intracytoplasmic A-particles from DBA/2 mouse leukemia cells. The enzyme activity was detected after disrupting the purified particles with 2 M NaCl-20 mM dithiothreitol. The presence of a divalent cation and all four deoxyribonucleoside triphosphates was essential for this enzyme activity. The enzyme had a clear preference for Mg2+ over Mn2+. Cesium sulfate isopycnic gradient centrifugation of the DNA product synthesized in the actinomycin D-containing reaction revealed the presence of DNA-RNA hybrid. Furthermore, the purified DNA product was found to hybridize with RNA isolated from A-particles. These observations strongly indicate that the endogenous A-particle RNA serves as the template for the DNA polymerase.
mesh_terms: D000818:Animals; D046508:Culture Techniques; D003593:Cytoplasm / Q000382:microbiology; D004279:DNA, Viral / Q000096:biosynthesis; D004789:Enzyme Activation; D017988:Gammaretrovirus / Q000201:enzymology* / Q000378:metabolism; D007942:Leukemia, Experimental; D008274:Magnesium / Q000494:pharmacology; D008345:Manganese / Q000494:pharmacology; D051379:Mice; D008811:Mice, Inbred DBA; D009368:Neoplasm Transplantation; D009693:Nucleic Acid Hybridization; D011119:Polynucleotides; D012194:RNA-Directed DNA Polymerase / Q000378:metabolism*; D013501:Surface-Active Agents / Q000494:pharmacology; D013698:Templates, Genetic
chemical_list: D004279:DNA, Viral; D011119:Polynucleotides; D013501:Surface-Active Agents; D008345:Manganese; D012194:RNA-Directed DNA Polymerase; D008274:Magnesium