Characterization of polyoma viral DNA sequences in polyoma-induced hamster tumor cell lines

The polyoma (PY) viral DNA sequences present in a series of hamster tumor cell lines were evaluated using the blotting technique of Southern ((1975) J. Mol. Biol. 98, 503-517). Remarkably, no cell line contained an intact distal portion of the early gene region which encodes a portion of the large T antigen. All cell lines examined contained the PY DNA Bum I fragment which contains most of the genetic information encoding PY small and middle T antigens, as well as the origin of viral DNA replication. These results provide an explanation for our previous observation that PY virus-induced hamster tumors do not contain the large species of T antigen.