Allele-specific suppression of temperature-sensitive mutations of the Saccharomyces cerevisiae RAD52 gene.

We screened for rad52 suppressors against temperature-sensitive (ts), missense, nonsense, and deletion rad52 mutations. Except for the deletion strain all mutants yielded suppressor candidates, indicating that suppressors completely bypassing the need for RAD52 are rare. Characterization of seven, recessive extragenic suppressors from our screen and two previously identified suppressors revealed that nearly all exhibit allele specificity. The allele specificity is positional in that suppressors that suppress a ts mutation in the C-terminal third of the coding region do not suppress three ts mutations in the N-terminal third. Conversely, suppressors against one of the three N-terminal mutations suppress more than one of these mutations but not the C-terminal mutation.