Mutational specificity of the anti 1,2-dihydrodiol 3,4-epoxide of 5-methylchrysene.

An SV40-based pS189 shuttle vector, which contained a supF target gene and was replicated in human cells (Ad293), was used to determine the mutational specificity of anti 5-methylchrysene 1,2-dihydrodiol 3,4-epoxide, the active metabolite of the environmentally prevalent carcinogen 5-methylchrysene. The frequency of supF mutants containing point mutations increased with dose to approximately 40 times the spontaneous frequency. The induced mutations were not randomly distributed but occurred preferentially at mutagenic hotspots, which were not all identical to those reported by others for benzo[a]pyrene dihydrodiol epoxide, a metabolite with similar chemistry.