Frameshift mutations produced by 9-aminoacridine in wild-type, uvrA and recA strains of Escherichia coli; specificity within a hotspot.

The endogenous tonB gene of Escherichia coli was used as a target for 9-aminoacridine-induced mutations that were identified in recA(-) and uvrA(-) cells. The cytotoxicity of 9-aminoacridine was enhanced in the uvrA and recA strains compared to the wild-type strain, and the mutagenicity of 9-aminoacridine in the uvrA and recA strains was similar to that in the wild type. For all three strains, the most common mutations were minus frameshifts in repetitive G:C base-pairs followed by minus frameshifts in nonrepetitive G:C base-pairs.