Detection of a subunit of cellular Pol II within highly purified preparations of RNA polymerase isolated from rabbit poxvirus virions.

A large (approximately 200 kd) subunit of cellular RNA polymerase II (Pol II) and a virus-encoded subunit of rabbit poxvirus (RPV) RNA polymerase (137 kd) react with common monoclonal antibodies. Hybridization studies with viral and cellular DNA clones confirm that the viral and cellular proteins are related. Following RPV infection, the Pol II subunit is translocated from the nucleus to the cytoplasmic virosomes, then packaged into mature virus, and is found associated with the viral RNA polymerase purified from virions. The results suggest that the cellular Pol II subunit may be directly involved in the transcription of viral genes.