Fission yeast switches mating type by a replication-recombination coupled process.
Fission yeast exhibits a homothallic life cycle, in which the mating type of the cell mitotically alternates in a highly regulated fashion. Pedigree analysis of dividing cells has shown that only one of the two sister cells switches mating type. It was shown recently that a site- and strand-specific DNA modification at the mat1 locus precedes mating-type switching. By tracking the fate of mat1 DNA throughout the cell cycle with a PCR assay, we identified a novel DNA intermediate of mating-type switching in S-phase. The time and rate of appearance and disappearance of this DNA intermediate are consistent with a model in which mating-type switching occurs through a replication-recombination coupled pathway. Such a process provides experimental evidence in support of a copy choice recombination model in Schizosaccharomyces pombe mating-type switching and is reminiscent of the sister chromatid recombination used to complete replication in the presence of certain types of DNA damage.
Arcangioli
B
B
Unite des Virus Oncogenes, URA 1644 du CNRS, Departement des Biotechnologies, Institut Pasteur, 25 rue du Dr Roux, 75724 Paris, Cedex 15, France.
de Lahondès
R
R
D004261:DNA Replication / Q000235:genetics*; D004271:DNA, Fungal / Q000235:genetics; D016195:G2 Phase; D005785:Gene Conversion / Q000235:genetics*; D005800:Genes, Fungal / Q000235:genetics*; D049770:Genes, Mating Type, Fungal; D005812:Genes, Switch / Q000235:genetics; D018392:Genomic Imprinting / Q000235:genetics; D007700:Kinetics; D008957:Models, Genetic; D009154:Mutation / Q000235:genetics; D016133:Polymerase Chain Reaction; D016196:S Phase; D012568:Schizosaccharomyces / Q000166:cytology / Q000235:genetics* / Q000254:growth & development; D012854:Sister Chromatid Exchange / Q000235:genetics
D004271:DNA, Fungal