Biochemical and Immunological Properties of the Reverse Transcriptase Associated with a Hamster Retrovirus

Abstract

Several properties of an RNA-directed DNA polymerase associated with a hamster retrovirus (HaRV) were examined and were similar to other polymerases from mammalian type-C viruses in that the enzyme is more active with Mn2+ than Mg2+, uses the reverse transcriptase-specific poly(rCm).cntdot.oligo(dG) template, possesses substantial endogenous polymerase activity and is strongly inhibited by homologous antisera and moderately inhibited by antisera directed against other type-C viruses. In contrast to previous reports of polymerases from other hamster viruses, HaRV polymerase is active in endogenous assays and the activity is associated with a 70,000 MW polypeptide in highly purified virions and with 70,000 and 85,0000 MW polypeptides in fresh, unpurified virus. Only 1 major peak of polymerase activity eluted from DEAE-cellulose while subsequent elution of this peak from phosphocellulose produced 2 major peaks of polymerase activity. The MW of these 2 peaks were 70,000 and 85,000 by glycerol density-gradient sedimentation. The HaRV reverse transcriptase and p[protein]30 were most closely related antigenically to other rodent retrovirus proteins.