Promoters of bovine papillomavirus type 1: in vitro activity and utilization.

Five of six bovine papillomavirus type 1 (BPV-1) promoters which were previously mapped by determining the 5' termini of viral mRNAs from bovine fibropapillomas and BPV-1-transformed cells were found to be active under in vitro transcription conditions. Transcription initiation at each of these promoters was accurate at the nucleotide level as determined by primer extension analysis. The most active promoter in vitro was P89, a typical RNA polymerase II promoter with both TATA and CAAT boxes. The promoters P7185 and P2443 also have TATA-like boxes, but none of the other promoters contain these typical regulatory elements.