Skip to main content
NCBI home page
Genetics logoLink to Genetics
. 1991 Dec;129(4):1033–1042. doi: 10.1093/genetics/129.4.1033

Swi6, a Gene Required for Mating-Type Switching, Prohibits Meiotic Recombination in the Mat2-Mat3 ``cold Spot'' of Fission Yeast

AJS Klar 1, M J Bonaduce 1
PMCID: PMC1204768  PMID: 1783290

Abstract

Mitotic interconversion of the mating-type locus (mat1) of the fission yeast Schizosaccharomyces pombe is initiated by a double-strand break at mat1. The mat2 and mat3 loci act as nonrandom donors of genetic information for mat1 switching such that switches occur primarily (or only) to the opposite mat1 allele. Location of the mat1 ``hot spot'' for transposition should be contrasted with the ``cold spot'' of meiotic recombination located within the adjoining mat2-mat3 interval. That is, meiotic interchromosomal recombination in mat2, mat3 and the intervening 15-kilobase region does not occur at all. swi2 and swi6 switching-deficient mutants possess the normal level of double-strand break at mat1, yet they fail to switch efficiently. By testing for meiotic recombination in the cold spot, we found the usual lack of recombination in a swi2 mutant but a significant level of recombination in a swi6 mutant. Therefore, the swi6 gene function is required to keep the donor loci inert for interchromosomal recombination. This finding, combined with the additional result that switching primarily occurs intrachromosomally, suggests that the donor loci are made accessible for switching by folding them onto mat1, thus causing the cold spot of recombination.

Full Text

The Full Text of this article is available as a PDF (2.1 MB).

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Bresch C., Müller G., Egel R. Genes involved in meiosis and sporulation of a yeast. Mol Gen Genet. 1968;102(4):301–306. doi: 10.1007/BF00433721. [DOI] [PubMed] [Google Scholar]
  2. Cao L., Alani E., Kleckner N. A pathway for generation and processing of double-strand breaks during meiotic recombination in S. cerevisiae. Cell. 1990 Jun 15;61(6):1089–1101. doi: 10.1016/0092-8674(90)90072-m. [DOI] [PubMed] [Google Scholar]
  3. Egel R., Beach D. H., Klar A. J. Genes required for initiation and resolution steps of mating-type switching in fission yeast. Proc Natl Acad Sci U S A. 1984 Jun;81(11):3481–3485. doi: 10.1073/pnas.81.11.3481. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Egel R. Frequency of mating-type switching in homothallic fission yeast. Nature. 1977 Mar 10;266(5598):172–174. doi: 10.1038/266172a0. [DOI] [PubMed] [Google Scholar]
  5. Egel R. Mating-type switching and mitotic crossing-over at the mating-type locus in fission yeast. Cold Spring Harb Symp Quant Biol. 1981;45(Pt 2):1003–1007. doi: 10.1101/sqb.1981.045.01.116. [DOI] [PubMed] [Google Scholar]
  6. Klar A. J., Bonaduce M. J., Cafferkey R. The mechanism of fission yeast mating type interconversion: seal/replicate/cleave model of replication across the double-stranded break site at mat1. Genetics. 1991 Mar;127(3):489–496. doi: 10.1093/genetics/127.3.489. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Klar A. J. The developmental fate of fission yeast cells is determined by the pattern of inheritance of parental and grandparental DNA strands. EMBO J. 1990 May;9(5):1407–1415. doi: 10.1002/j.1460-2075.1990.tb08256.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Meade J. H., Gutz H. Influence of the mat1-M Allele on Meiotic Recombination in the Mating-Type Region of SCHIZOSACCHAROMYCES POMBE. Genetics. 1978 Feb;88(2):235–238. doi: 10.1093/genetics/88.2.235. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. Moreno S., Klar A., Nurse P. Molecular genetic analysis of fission yeast Schizosaccharomyces pombe. Methods Enzymol. 1991;194:795–823. doi: 10.1016/0076-6879(91)94059-l. [DOI] [PubMed] [Google Scholar]
  10. Nakaseko Y., Adachi Y., Funahashi S., Niwa O., Yanagida M. Chromosome walking shows a highly homologous repetitive sequence present in all the centromere regions of fission yeast. EMBO J. 1986 May;5(5):1011–1021. doi: 10.1002/j.1460-2075.1986.tb04316.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. Nielsen O., Egel R. Mapping the double-strand breaks at the mating-type locus in fission yeast by genomic sequencing. EMBO J. 1989 Jan;8(1):269–276. doi: 10.1002/j.1460-2075.1989.tb03373.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  12. Perkins D. D. Biochemical Mutants in the Smut Fungus Ustilago Maydis. Genetics. 1949 Sep;34(5):607–626. doi: 10.1093/genetics/34.5.607. [DOI] [PMC free article] [PubMed] [Google Scholar]
  13. Szostak J. W., Orr-Weaver T. L., Rothstein R. J., Stahl F. W. The double-strand-break repair model for recombination. Cell. 1983 May;33(1):25–35. doi: 10.1016/0092-8674(83)90331-8. [DOI] [PubMed] [Google Scholar]
  14. Wallis J. W., Chrebet G., Brodsky G., Rolfe M., Rothstein R. A hyper-recombination mutation in S. cerevisiae identifies a novel eukaryotic topoisomerase. Cell. 1989 Jul 28;58(2):409–419. doi: 10.1016/0092-8674(89)90855-6. [DOI] [PubMed] [Google Scholar]
  15. van Solingen P., van der Plaat J. B. Fusion of yeast spheroplasts. J Bacteriol. 1977 May;130(2):946–947. doi: 10.1128/jb.130.2.946-947.1977. [DOI] [PMC free article] [PubMed] [Google Scholar]

Articles from Genetics are provided here courtesy of Oxford University Press

RESOURCES