[Role of the oncogene in the mutagenic activity of bovine adenovirus type 3].

The mutagenic and carcinogenic effect of two EcoRI-fragments of bovine adenovirus type 3 (BAV-3) DNA inserted into pBR325 has been studied. The C fragment (located between 3,6 and 19,7 map units) contains the viral oncogene, the C fragment (between 44,3 and 63,7 map units) displays no transforming activity. It has been established that oncogene BAV-3 statistically true increases the yield of mutants resistant to 6-mercaptopurine (6MP) in Chinese hamster cells. The C fragment, pBR325 without viral sequences and DNA fragments of different molecular weights from normal Syrian hamster cells have no mutagenic effect. The control over tumor formation in syngenic mice after injection of C3H10T 1/2 and D. C fragments and pBR325 treatment exposed a parallelism between the mutagenic and transforming effect. The study of the combined effect of viral DNA fragments and the tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA) which increases the transforming activity of different carcinogens, shows that the promoter increases the frequency of mutants after viral oncogene treatment and does not induce mutagenic activity of those types of DNA which are unable to transform the cells.