CONDITIONAL HYPORECOMBINATION MUTANTS OF 3 REC GENES OF SACCHAROMYCES-CEREVISIAE

We have isolated and characterized three conditional hyporecombination mutants, rec1-1, rec3-1 and rec4-1, that define three REC genes of Saccharomyces cerevisiae required for spontaneous general mitotic interchromosomal recombination. Each MATa/MATα rec/rec diploid is deficient in mitotic single site gene conversion, intragenic recombination, intergenic recombination and sporulation at the restrictive temperature (36°C). The rec1-1 mutation also confers conditional enhanced sensitivity to the killing effects of X-rays. The rec1-1 and rec3-1 mutations have been mapped to chromosome VII. The rec1-1, rec3-1 and rec4-1 mutations exhibit complementation at 36°C for both mitotic recombination and sporulation. © 1990 Springer-Verlag.