Characterization of the DNA of the hamster papovavirus: IV. Transcription mapping of calf-thymus DNA polymerase II.

Nascent RNA, synthesized by calf thymus RNA polymerase II on restriction endonuclease BamHI linearized hamster papovavirus (HaPV) DNA, was rehybridized to the template strand under conditions allowing transcription R-loop formation. Hybrids, visualized by electron microscopy, were plotted and mapped according to the physical map of HaPV. Two predominant regions of transcription could be localized at 0.10--0.40 and 0.50--0.82 m.u., respectively. For the start sites of transcription at map positions 0.67 and 0.75, respectively, on the HaPV genome a transcription in opposite direction were estimated. This genome region harbours the putative origin of replication of HaPV DNA. These results suggest a distinct relatedness of HaPV to the polyomavirus group.