The role of the nuclear gene "mitochondrial mutability control" (MMC1) in the process of mutability of the mitochondrial genome by different mutagens in Saccharomyces cerevisiae.

The accumulation of respiratory deficient (RD) mutants in Saccharomyces cerevisiae depended upon the mutagens used and upon the presence of the nuclear gene previously identified as MMC1 (one) which we showed to control the spontaneous and the erythromycin-induced RD mutability. In this paper data are reported about the accumulation of RD mutants in the presence of manganous ions (Mn++) and UV which was higher in the mmc1 (one) than in MMC1 strains. We found that the characters 'low spontaneous' and 'low induced' RD mutability by erythromycin, manganous ions and UV, were controlled by the same genetic determinant. In the presence of manganous ions, also the frequency of antibiotic resistant mutants capR and eryR was higher in the mmc1 strains. Moreover, the accumulation of RD mutants in the presence of berenil, 5-fluorouracil and basic fuchsin was higher in the mmc1 than in MMC1 strains. In contrast, RD mutants accumulation by acriflavine and ethidium bromide treatments did not appear affected by the MMC1 genetic constitution.