Polyoma virus gene activity during lytic infection and in transformed animal cells.

Randomly labeled RNA's from animal cells either productively infected or transformed by polyoma virus were used to measure virus DNA transcription. During lytic infection, 50 percent of polyoma virus DNA was expressed. In two different polyoma-transformed hamster cell lines, the same 20 percent of the virus genome was transcribed. About 10 percent of polyoma DNA was expressed in the one mouse transformed cell line examined.