MAR1—A REGULATOR OF THE HMa AND HMα LOCI IN SACCHAROMYCES CEREVISIAE

[摘要] A mutation in the MAR1 (mating-type regulator) locus causing sterility in Saccharomyces cerevisiae is reported. The mutation maps on the left arm of linkage group IV between trp1 and cdc2 at a distance of about 27 CM from trp 1 and about 31 cM from cdc 2. Haploid strains with genotype MAT α HM α HMa mar1-1 and MAT a HM α HM a mar1-1 are sterile. However, MAT α hm α HM a mar1-1 and MAT a HM α hm a mar1-1 strains exhibit a and a mating type, respectively. The sterile strains can be "rare mated" with standard strains as a consequence of mutational changes at HM a and HM α. It is proposed that the MAR1 locus blocks the expression of MAT α and MAT a information thought to exist at HM a and HM α loci, respectively (HICKS, STRATHERN and HERSKOWITZ, 1977). In a mar1-1 mutant, the expression of both HM α and HM a information leads to a nonmating phenotype similar to that of MAT a/ MAT α diploids. The genetic evidence reported here is consistent with a central feature of the "cassette model", namely that HM α and hm a carry MAT a information and HM a and hm α carry MAT α information.

[学科分类] 医学（综合）