title: [Relation of RNA-dependent DNA-polymerase from the rat liver with virus-like particles].
abstract: RNA-dependent DNA-polymerase activity was found in the 165 000 g supernatant and pellet of the postmitochondrial rat liver fraction. Further fractionation of the 165 000 g pellet in the linear sucrose gradient (20-50%) showed that RNA-dependent DNA-polymerase activity was distributed between fractions with densities 1.18-1.19 g/ml and 1.09-1.1 g/ml. In the fractions with 1.18-1.19 g/ml density the enzymic activity could be detected only after Triton X-100 treatment and disappeared after the incubation with pancreatic ribonuclease A. Triton X-100 treatment of the 165 000 g supernatant and the fractions with density 1.09-1.1 g/ml did not increase further the enzymic activity. Electron microscopy revealed in the 1.18 g/ml fraction virus-like particles resembling retroviruses of A and C type. In the light peak "non-mature" virus-like particles were found. The 165 000 g supernatant devoid of virus-like particles contained free RNA-dependent DNA-polymerase activity. The virus-like particles of both types seem to be endogenous rat retroviruses serving as a source of the particular and free reverse transcriptase in the rat liver.
mesh_terms: D000818:Animals; D002458:Cell Fractionation; D005814:Genes, Viral; D008099:Liver / Q000201:enzymology* / Q000382:microbiology; D008930:Mitochondria, Liver / Q000201:enzymology / Q000382:microbiology; D017830:Octoxynol; D011092:Polyethylene Glycols; D012194:RNA-Directed DNA Polymerase / Q000235:genetics / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D012190:Retroviridae / Q000201:enzymology* / Q000235:genetics; D014771:Virion / Q000201:enzymology / Q000235:genetics
chemical_list: D011092:Polyethylene Glycols; D017830:Octoxynol; D012194:RNA-Directed DNA Polymerase
vernacular_title: Sviaz' RNK-zavisimoĭ DNK-polimerazy iz pecheni krys s virusopodobnymi chastitsami.