Mutagenicity of 3-azido-1,2-propanediol and 9-(3-azido-2-hydroxypropyl)-adenine in repair deficient strains of Escherichia coli.

The mutagenicity of two non-aromatic organic azido compounds, 3-azido-1,2-propanediol (AG) and 9-(3-azido-2-hydroxypropyl)-adenine (AHPA), was studied in E. coli repair deficient strains uvrA6, uvrA6 + umuC36, uvrA6+ umuC122::Tn5, polA1, tagA1+ alkA1, ada and dam3. The mutagenicity of both agents was markedly enhanced by defects of UvrABC excinuclease (uvrA6) and was independent of umuC function of the SOS error-prone pathway. Neither azido compound promoted umuDC operon expression. The mutagenicity of AG in tag A1, alkA1 and ada mutants does not differ from that found in the wild-type strain. The expression of both ada and alkA genes was not elevated by AG. Experiments on polA1 and dam3 mutants suggest that DNA polymerase I as well as the mutHLS mismatch repair pathway does not contribute to the removal of putative DNA lesions induced by AG.