A bovine papilloma virus vector with a dominant resistance marker replicates extrachromosomally in mouse and E. coli cells

We describe the construction of a bovine papilloma virus‐based vector (pCGBPV9) which contains a dominant selectable marker and replicates autonomously in both mouse and Escherichia coli cells. This vector contains the complete bovine papilloma virus genome, a ColE1 replication origin and a dominant selectable marker conferring resistance to kanamycin in bacteria and G418 in eukaryotic cells. A high number of G418R colonies are obtained after transfer of pCGBPV9 into mouse C127 cells. These G418R colonies contain vector DNA which replicates autonomously at approximately 10‐30 copies per cell. The molecules are in most cases unrearranged and can be rescued into E. coli cells by bacterial transformation.