The Physical State of Hybrid Genomes Containing Simian Virus 40 and Bovine Papilloma Virus DNA Sequences in Transformed Clonal Cell Lines

Abstract

SUMMARYTO test whether the covalent linkage of simian virus 40 (SV40) A gene DNA sequences might lead to integration of bovine papilloma virus type 1 (BPV-1) DNA sequences, recombinant pBR322 plasmids containing both the transforming region of the BPV-I 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.

Viral Expression Vectors

“…This ensures efficient transfection, stable maintenance, and facile recovery of plasmid DNAs. This situation is in marked contrast to BPV based vectors, wherein several different inserts lead to deletion, rearrangement, recombination, or integration (for examples see MITRANI-RoSENBAUM et al 1983;WANG et al 1983;ZINN et al 1983;DIMAIO et al 1984;HSIUNG et al 1984;LEHN and SAUER 1984;PINTEL et al 1984). The present list includes: metabolically required enzymes [tk (YATES et al 1985), hprt (MARGOLSKEE et al 1988;Y.…”