This vector is suitable for introduction of foreign genes into mouse mammary tumor cell line C1271 (ATCC CRL 1616). (ATCC staff) The complete BPV genome was cloned into the BamHI site of pBR322. Medium is 1227 LB plus ampicillin. Hosts: E.coli HB101, vertebrate cells, E.coli, C127I cell line [ATCC CRL 1616].