The action of 4-hydroxyaminobiphenyl in Escherichia coli: cytotoxic and mutagenic effects in DNA repair deficient strains.

The cytotoxic and mutagenic effects of 4-hydroxyaminobiphenyl (N-OH-ABP) were studied using Escherichia coli strains with different repair capacities. N-OH-ABP was equally cytotoxic for uvrA and recA mutants as well as in wild-type cells while polA mutant strains proved particularly sensitive to its toxicity. In contrast, the mutation frequency in the uvrA strains tested was elevated to 30-400-fold the wild-type values. We suggest that aminobiphenyl-DNA adducts responsible for mutation are repaired by UVR endonuclease but different pathways exist for removal of DNA lesions responsible for bacterial killing. From the 32P-postlabeling analysis, it was concluded that ABP-DNA adducts can be relatively rapidly repaired in wild-type strains, while persisting in the uvrA strains.