Avian sarcoma virus PRCII: Conditional mutants temperature sensitive in the maintenance of fibroblast transformation

Avian sarcoma virus PRCII was mutagenized with 5-azacytidine, and from single foci of transformed cells induced by this virus preparation three conditional mutants were isolated that are temperature sensitive for oncogenic transformation of fibroblasts. Two of these, LA42 and LA47, are not affected in their replication potential at the nonpermissive temperature (41.5°) nor are the virions heat labile. The third mutant, LA46, is coordinately temperature sensitive in replication and transformation. A shift of the incubation temperature from 36° to 41.5° at any time after infection causes transformed cells by any one of the three mutants to revert to normal morphology.