Switching of a mating-type a mutant allele in budding yeast Saccharomyces cerevisiae

Klar, A. J., Fogel, S., Radin, D. N. (July 1979) Switching of a mating-type a mutant allele in budding yeast Saccharomyces cerevisiae. Genetics, 92 (3). pp. 759-76. ISSN 0016-6731 (Print)0016-6731 (Linking)

URL: http://www.ncbi.nlm.nih.gov/pubmed/395020

Abstract

Aimed at investigating the recovery of a specific mutant allele of the mating type locus (MAT) by switching a defective MAT allele, these experiments provide information bearing on several models proposed for MAT interconversion in bakers yeast, Saccharomyces cerevisiae. Hybrids between heterothallic (ho) cells carrying a mutant MAT a allele, designated mata-2, and MAT alpha ho strains show a high capacity for mating with MATa strains. The MAT alpha/mata-2 diploids do not sporulate. However, zygotic clones obtained by mating MAT alpha homothallic (HO) cells with mata-2 ho cells are unable to mate and can sporulate. Tetrad analysis of such clones revealed two diploid (MAT alpha/MATa):two haploid segregants. Therefore, MAT switches occur in MAT alpha/mata-2 HO/ho cells to produce MAT alpha/Mata cells capable of sporulation. In heterothallic strains, the mata-2 allele can be switched to a functional MAT alpha and subsequently to a functional MATa. Among 32 MAT alpha to MATa switches tested, where the MAT alpha was previously derived from the mata-2 mutant, only one mata-2 like isolate was observed. However, the recovered allele, unlike the parental allele, complements the matalpha ste1-5 mutant, suggesting that these alleles are not identical and that the recovered allele presumably arose as a mutation of the Mat alpha locus. No mata-2 was recovered by HO-mediated switching of MAT alpha (previously obtained from mata-2 by HO) in 217 switches analyzed. We conclude that in homothallic and heterothallic strains, the mata-2 allele can be readily switched to a functional MAT alpha and subsequently to a functional MATa locus. Overall, the results are in accord with the cassette model (HICKS, STRATHERN and HERSKOWITZ )977b) proposed to explain MAT interconversions.

Item Type: Paper
Uncontrolled Keywords: *Alleles Models, Genetic *Mutation Phenotype Saccharomyces cerevisiae/*genetics/physiology Spores, Fungal
Subjects: bioinformatics > genomics and proteomics > genetics & nucleic acid processing > DNA, RNA structure, function, modification > genes, structure and function > alleles
bioinformatics > genomics and proteomics > genetics & nucleic acid processing > DNA, RNA structure, function, modification > genes, structure and function
bioinformatics > genomics and proteomics > genetics & nucleic acid processing > DNA, RNA structure, function, modification > mutations
organism description > yeast
CSHL Authors:
Communities: CSHL labs
Depositing User: Matt Covey
Date: July 1979
Date Deposited: 12 May 2016 20:15
Last Modified: 12 May 2016 20:15
PMCID: PMC1214035
Related URLs:
URI: http://repository.cshl.edu/id/eprint/32700

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