Protoplast fusion of Schizosaccharomyces pombe auxotrophic mutants of identical mating-type

1977 ◽  
Vol 151 (1) ◽  
pp. 77-81 ◽  
Author(s):  
M. Sipiczki ◽  
L. Ferenczy
Keyword(s):  
Schizosaccharomyces Pombe ◽  
Protoplast Fusion ◽  
Mating Type ◽  
Auxotrophic Mutants

scholarly journals A NEW TYPE OF MUTATION IN SCHIZOSACCHAROMYCES POMBE: VEGETATIVE IODINE REACTION

Genetics ◽  
1975 ◽  
Vol 80 (4) ◽  
pp. 711-714
Author(s):  
James H Meade ◽  
Herbert Gutz
Keyword(s):  
Schizosaccharomyces Pombe ◽  
Mating Type ◽  
Nitrous Acid ◽  
New Gene ◽  
New Type ◽  
Mating Type Genes ◽  
Iodine Reaction

ABSTRACT Colonies of Schizosaccharomyces pombe that contain ascospores (e.g., colonies of homothallic strains) turn black after treatment with iodine vapors. Heterothallic strains of S. pombe normally do not show this reaction. In experiments with the latter strains we found mutants which exhibit a positive iodine reaction though they do not contain ascospores. This phenotype is due to mutations in a new gene, vir1 (vegetative iodine reaction). The vir1 locus is not linked with the mating-type genes.—Strains of mating-type h-s are known not to give any spontaneous mating-type mutations. Mating-type mutations were also not found after treatment with nitrous acid.

scholarly journals MATING-TYPE MUTATIONS IN SCHIZOSACCHAROMYCES POMBE: ISOLATION OF MUTANTS AND ANALYSIS OF STRAINS WITH AN h  - or h  + PHENOTYPE

Genetics ◽  
1976 ◽  
Vol 83 (2) ◽  
pp. 259-273
Author(s):  
James H Meade ◽  
Herbert Gutz
Keyword(s):  
Schizosaccharomyces Pombe ◽  
Gene Product ◽  
Mating Type ◽  
Sexual Cycle ◽  
Type Region ◽  
Type Allele ◽  
Mating Type Gene ◽  
Auxiliary Gene ◽  
Type Gene

ABSTRACT Mutants defective in various steps of the sexual cycle have been isolated from homothallic strains of Schizosaccharomyces pombe by Bresch, Müller and Egel (1968). These mutants include heterothallic h  + and h  - strains. We have isolated additional h  + and h  -mutants from homothallic strains. Those mutants which are due to mutations in the mating-type region were analyzed in detail. Our results show that the mating-type gene mat2 not only has a function in copulation and meiosis, but that it also regulates the formation of the map1 gene product (map1 is a mating-type auxiliary gene). Some of the h  - mutants have lost only one of the three functions while others are defective in at least two, and perhaps all three, functions. Further, we show that the mat1  - allele of h90 strains can mutate to mat1  + but that mutations in mat2 appear to affect the mutational behavior of mat1. Finally, we describe a new inactive mating-type allele, mat2*, which is different from mat2  0 in that it can mutate to mat2  +.

Sap1, a protein that binds to sequences required for mating-type switching, is essential for viability in Schizosaccharomyces pombe

1994 ◽  
Vol 14 (3) ◽  
pp. 2058-2065
Author(s):  
B Arcangioli ◽  
T D Copeland ◽  
A J Klar
Keyword(s):  
Dna Binding ◽  
Schizosaccharomyces Pombe ◽  
Mating Type ◽  
Biochemical Characterization ◽  
Strand Break ◽  
Double Strand Break ◽  
Type Locus ◽  
Protein Motifs ◽  
Mating Type Switching

The pattern of mating-type switching in cell pedigrees of the fission yeast Schizosaccharomyces pombe is dictated by the inheritance of specific DNA chains at the mating-type locus (mat1). The recombination event essential for switching is initiated by a site-specific double-strand break at mat1. The switch-activating protein, Sap1, binds in vitro to a mat1 cis-acting site that was shown earlier to be essential for efficient mating-type switching. We isolated the sap1 gene by using oligonucleotides corresponding to the amino acid sequence of purified Sap1 protein. The sequence of that gene predicted a 30-kDa protein with no significant homology to other canonical DNA-binding protein motifs. To facilitate its biochemical characterization, Sap1 was expressed in Escherichia coli. The protein expressed in bacteria displayed the same DNA-binding specificities as the protein purified from S. pombe. Interestingly, analysis of a sap1 null mutation showed that the gene is essential for growth even in a strain in which mating-type switching is prohibited because of a defect in generation of the double-strand break. Thus, the sap1 gene product implicated in mating-type switching is shown to be essential for cell viability.

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