A cytoplasmic factor involved in the expression of resistance to C8-ATC in Saccharomyces cerevisiae.

A dozen mutants of Saccharomyces cerevisiae, resistant to C8-ATC have been characterized. C8-ATC was previously established as a biologically toxic compound. Frequency of mutants (10(-7)) was typical for spontaneous mutations. One very stable mutant was characterized extensively. The genetical analysis revealed that resistance in this mutant was determined by single-gene mutation. The rho 0 cells, obtained by ethidium bromide (EB) mutagenesis of the resistant strain, were completely devoid of resistance. A large percentage of rho- cells, obtained by a moderate EB treatment of resistant cells were still able to express resistance to C8-ATC. Therefore we hypothesized that, in our particular strain, a cytoplasmic factor is involved in nuclear determination of resistance.