Isolation of polyomavirus mutants multiadapted to murine embryonal carcinoma cells

Polyomavirus mutants were isolated from PCC4 embryonal carcinoma cells infected with a variant strain of polyomavirus (ev 1001h) and were found to contain a tandem duplication overlapping the enhancers and the origin of replication. These mutants were able to infect several lines of embryonal carcinoma cells, including PCC4, F9, and LT1. The sequence and structure of one of these mutants are presented and compared with those of other PyEC PCC4 mutants previously described.