Induction of the SOS response by ICR191 does not influence frameshift mutagenesis at the hisC3076 marker of Salmonella typhimurium

Abstract

Reversion of the Salmonella typhimurium frameshift marker hisC3076 by ICR191 and 9-aminoacridine in rec+ and recA1 backgrounds was examined using the standard plate-reversion assay. For both compounds, the level of reversion observed in the recA strain is significantly greater than in the rec+ strain. Thus reversion of hisC3076 is not recA-dependent, but is recA-modulated. The ability of a mutagen (or mutagenic treatment) to induce the recA lexA-dependent SOS response does not therefore imply that mutagenic effects will also be recA-dependent.