Requirement of HSM3 gene for spontaneous mutagenesis in Saccharomyces cerevisiae.

In this work, we studied the influence of hsm3 mutation on spontaneous mutagenesis in actively and slowly dividing cells. We demonstrated that the spontaneous mutation rates in the hsm3 mutant and the wild type strain were similar in actively dividing cells. However, during 15-day cultivation of both strains we observed higher accumulation of mutants in the hsm3 strain compared with those in the wild type cells.

The yeast HSM3 gene acts in one of the mismatch repair pathways.

Mutants with enhanced spontaneous mutability (hsm) to canavanine resistance were induced by N-methyl-N-nitrosourea in Saccharomyces cerevisiae. One bearing the hsm3-1 mutation was used for this study. This mutation does not increase sensitivity to the lethal action of different mutagens.