Characterization of transforming viruses rescued from a hamster tumour cell line harbouring the v-src gene flanked by long terminal repeats.

The organization of proviruses derived from infecting transforming viruses rescued from hamster tumour cells was studied. Southern blot analysis indicated that the provirus from the F6 cell line was organized as long terminal repeat (LTR)-src-LTR, and S1 mapping experiments suggested that it was probably derived by reverse transcription of src mRNA followed by integration. In the E6 cell line, the provirus unit was arranged as LTR-delta gag-src-LTR, indicating a recombination event between the rescued transforming virus and the helper virus. These results suggest that transforming defective viruses containing only the src gene can be rescued from nonpermissive mammalian cells.