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Genetics

Title:		Mutations affecting donor preference during mating type interconversion in Saccharomyces cerevisiae
Author(s):		Weiler KS; Szeto L; Broach JR;
Address:		"Department of Molecular Biology, Princeton University, New Jersey 08544-1014, USA"
Journal Title:		Genetics
Year:		1995
Volume:		139
Issue:		4
Page Number:		1495 - 1510
DOI:		10.1093/genetics/139.4.1495
ISSN/ISBN:		0016-6731 (Print) 0016-6731 (Linking)
Abstract:		"Homothallic strains of Saccharomyces cerevisiae can convert mating type from a to alpha or alpha to a as often as every generation, by replacing genetic information specifying one mating type at the expressor locus, MAT, with information specifying the opposite mating type. The cryptic mating type information that is copied and inserted at MAT is contained in either of two loci, HML or HMR. The particular locus selected as donor during mating type interconversion is regulated by the allele expressed at MAT. MATa cells usually select HML, and MAT alpha cells usually select HMR, a process referred to as donor preference. To identify factors required for donor preference, we isolated and characterized a number of mutants that frequently selected the nonpreferred donor locus during mating type interconversion. Many of these mutants were found to harbor chromosome rearrangements or mutations at MAT or HML that interfered with the switching process. However, one mutant carried a recessive allele of CHL1, a gene previously shown to be required for efficient chromosome segregation during mitosis. Homothallic strains of yeast containing a null allele of CHL1 exhibited almost random selection of the donor locus in a MATa background but were normal in their ability to select HMR in a MAT alpha background. Our results indicate that Chl1p participates in the process of donor selection and are consistent with a model in which Chl1p helps establish an intrinsic bias in donor preference"
Keywords:		"Alleles Base Sequence Chromosome Mapping Chromosomes, Fungal DNA Primers Gene Rearrangement Genes, Recessive Mating Factor Molecular Sequence Data *Mutation Peptides/*genetics Phenotype Saccharomyces cerevisiae/classification/*genetics/physiology Transloc;"
Notes:		"MedlineWeiler, K S Szeto, L Broach, J R eng 5T32GM-07388/GM/NIGMS NIH HHS/ Research Support, U.S. Gov't, P.H.S. 1995/04/01 Genetics. 1995 Apr; 139(4):1495-510. doi: 10.1093/genetics/139.4.1495"