DNA Polymerase Activities and Nucleic Acid Components of Virions Isolated from a Spontaneous Mammary Carcinoma from a Rhesus Monkey

Virions isolated from a spontaneous mammary carcinoma of a rhesus monkey and propagated in human cells possess an RNA-instructed DNA polymerase. They also exhibit DNA polymerase activities that respond to either double-stranded DNA or synthetic RNA·DNA hybrid complexes as templates. The virion has been shown to have a density of 1.16 g/ml and to contain a nucleic acid species of high molecular weight (sedimentation coefficient, 60-70 S), which bands as RNA at 1.670 in a Cs₂SO₄ equilibrium density gradient. In addition, the virions contain species of low molecular weight (4-6 S) that consist of RNA as well as components banding at densities characteristic of DNA·RNA complexes. The nucleoid of this virion has been isolated and shown to have a density of 1.23 g/ml; it also contains a 60-70S nucleic acid species.