Cottontail rabbit papillomavirus-specific transcripts in transplantable tumors with integrated DNA

The viral DNA and viral transcripts of a VX2 and a VX7 transplantable carcinoma lines were analyzed. Both tumor lines contain equivalent numbers of gene copies per cell of exclusively integrated viral DNA. Integration is in head-to-tail tandem repeats, in probably three sites and at least two integration sites are common. In both tumors, about half of the viral genomes share a 90-bp deletion. Common integration sites and deletions suggest that the two tumor lines were derived from the same parent tumor. The tumors contain the same major viral transcripts of 1.3 and 2.0 kb also found in both papillomas and primary carcinomas of domestic rabbits [M. Nasseri, F. O. Wettstein, and J. G. Stevens, J. Virol. 44, 263-268 (1982)]. However, the carcinoma lines differ in their minor transcripts. VX7 has four minor transcripts of 5.2, 3.8, 3.6, and 3.0 kb and VX2 has two of 4.8 and 3.0 kb. The 4.8-kb transcript is relatively major and appears to be identical to a major transcript present in virus-producing tumors of cottontail rabbits [M. Nasseri and F. O. Wettstein, J. Virol. 51, 706-712 (1984)].