Use of a cellular polyadenylation signal by viral transcripts in polyoma virus transformed cells

The DNA sequences at and around the junctions between viral and cellular DNA in the polyoma virus transformed mouse cell line, TS-A-3T3, have been determined. No common sequence specificity or structural features at the joins have been observed. The sequence indicates that the 94K truncated large T antigen found in TS-A-3T3 cells is a hybrid protein in which the carboxy-terminal 19 amino acids are encoded by adjacent host sequences. Moreover, the three early region transcripts initiated in viral sequences are also hybrid in nature and appear to utilize a host polyadenylation signal associated with the hexanucleotide, AATAAA, found 100 bp beyond a viral-host join.