title: The Rad52 homologs Rad22 and Rti1 of Schizosaccharomyces pombe are not essential for meiotic interhomolog recombination, but are required for meiotic intrachromosomal recombination and mating-type-related DNA repair.
abstract: Proteins of the RAD52 epistasis group play an essential role in repair of some types of DNA damage and genetic recombination. In Schizosaccharomyces pombe, Rad22 (a Rad52 ortholog) has been shown to be as necessary for repair and recombination events during vegetative growth as its Saccharomyces cerevisiae counterpart. This finding contrasts with previous reports where, due to suppressor mutations in the fbh1 gene, rad22 mutants did not display a severe defect. We have analyzed the roles of Rad22 and Rti1, another Rad52 homolog, during meiotic recombination and meiosis in general. Both proteins play an important role in spore viability. During meiotic prophase I, they partially colocalize and partially localize to Rad51 foci and linear elements. Genetic analysis showed that meiotic interchromosomal crossover and conversion events were unexpectedly not much affected by deletion of either or both genes. A strong decrease of intrachromosomal recombination assayed by a gene duplication construct was observed. Therefore, we propose that the most important function of Rad22 and Rti1 in S. pombe meiosis is repair of double-strand breaks with involvement of the sister chromatids. In addition, a novel mating-type-related repair function of Rad22 specific to meiosis and spore germination is described.
authors.affiliation: Institute of Cell Biology, University of Bern, CH-3012 Bern, Switzerland.
authors.forename: Guillaume
authors.initials: G
authors.lastname: Octobre
authors.forename: Alexander
authors.initials: A
authors.lastname: Lorenz
authors.forename: Josef
authors.initials: J
authors.lastname: Loidl
authors.forename: Jürg
authors.initials: J
authors.lastname: Kohli
mesh_terms: D002467:Cell Nucleus / Q000378:metabolism; D015825:Chromosomes, Fungal / Q000235:genetics*; D003433:Crosses, Genetic; D004260:DNA Repair; D004268:DNA-Binding Proteins / Q000378:metabolism*; D017353:Gene Deletion; D049770:Genes, Mating Type, Fungal; D008540:Meiosis; D050296:Microbial Viability; D008938:Mitosis; D008957:Models, Genetic; D009154:Mutation / Q000235:genetics; D010641:Phenotype; D021381:Protein Transport; D051135:Rad51 Recombinase / Q000378:metabolism; D051721:Rad52 DNA Repair and Recombination Protein / Q000737:chemistry*; D011995:Recombination, Genetic / Q000235:genetics*; D012568:Schizosaccharomyces / Q000166:cytology / Q000235:genetics* / Q000254:growth & development; D029702:Schizosaccharomyces pombe Proteins / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D013172:Spores, Fungal / Q000166:cytology / Q000235:genetics
chemical_list: D004268:DNA-Binding Proteins; D051721:Rad52 DNA Repair and Recombination Protein; D029702:Schizosaccharomyces pombe Proteins; C085412:rad52 protein, S pombe; D051135:Rad51 Recombinase