Abstract
To test whether the covalent linkage of SV40 A gene DNA sequences might lead to integration of bovine papillomavirus type I (BPV-1) DNA sequences, recombinant pBR322 plasmids containing both the transforming region of the BPV-1 genome and the SV40 A gene were used for transformation of rodent cells. Plasmids containing both regions transformed with higher efficiency than plasmids containing either region alone. Various clonal cell lines were established and examined with regard to the physical state, and the expression of the viral DNA sequences. BPV-1 RNA sequences were detected and the SV40 T-antigen was expressed. The plasmid sequences persisted in all cases in an unintegrated state. In no case was it possible to find evidence for integration of BPV-1 sequences.