Evidence for a particle-associated RNA-directed DNA polymerase in rabbit placental and uterine tissues

A RNA-directed DNA polymerase associated with particles that band at a density characteristic of type C RNA viruses was found in normal rabbit placental and uterine tissues taken during the early stages of gestation. That the rabbit RNA-directed DNA polymerase is distinct from the known cellular DNA polymerases and similar to the RNA-directed DNA polymerase of mammalian type C RNA viruses is shown by column chromatographic characteristics, template primer preferences, molecular weight determination, and an absolute requirement for the divalent cations.