Mutation frequencies from X-rays, ultraviolet light, and methyl methanesulfonate in Chinese hamster ovary cells incubated with 3-aminobenzamide.

An inhibitor of polyadenosine diphosphoribose polymerase, 3-aminobenzamide, had no effect on survival or mutagenesis in Chinese hamster ovary cells exposed to X-rays or u.v. light. After exposure to methyl methanesulfonate, 3-aminobenzamide increased cell killing and mutagenesis at the 6-thio-guanine-resistance locus, but had no effect on mutagenesis at the ouabain-resistance locus. These results are consistent with the greater role played by polyadenosine diphosphoribose in cells damaged by alkylating agents rather than by radiations.