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We have identified in the fission yeast Schizosaccharomyces pombe a MutS homolog that shows highest homology to the Msh2 subgroup. msh2 disruption gives rise to increased mitotic mutation rates and increased levels of postmeiotic segregation of genetic markers. In bandshift assays performed with msh2Delta cell extracts, a general mismatch-binding activity is absent. By complementation assays, we showed that S. pombe msh2 is allelic with the previously identified swi8 and mut3 genes, which are involved in mating-type switching. The swi8-137 mutant has a mutation in the msh2 gene which causes a truncated Msh2 peptide lacking a putative DNA-binding domain. Cytological analysis revealed that during meiotic prophase of msh2-defective cells, chromosomal structures were frequently formed; such structures are rarely found in the wild type. Our data show that besides having a function in mismatch repair, S. pombe msh2 is required for correct termination of copy synthesis during mating-type switching as well as for proper organization of chromosomes during meiosis.


  • Alleles, Base Pair Mismatch, Base Sequence, Chromosomes, Fungal, Cloning, Molecular, DNA Repair, DNA, Fungal, DNA-Binding Proteins, Fungal Proteins, Genes, Fungal, Genes, Mating Type, Fungal, Meiosis, Mitosis, Molecular Sequence Data, MutS Homolog 2 Protein, Nucleic Acid Conformation, Prophase, Schizosaccharomyces, Schizosaccharomyces pombe Proteins, Spores, Fungal, Journal Article, Research Support, Non-U.S. Gov't
Original languageEnglish
Pages (from-to)241-50
Number of pages10
JournalMolecular and Cellular Biology
Issue number1
Publication statusPublished - Jan 1999
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