Two different Swi5-containing protein complexes are involved in mating-type switching and recombination repair in fission yeast

Proc Natl Acad Sci U S A. 2003 Dec 23;100(26):15770-5. doi: 10.1073/pnas.2632890100. Epub 2003 Dec 8.


Homologous recombination is an important biological process that occurs in all organisms and facilitates genome rearrangements and repair of DNA double-strand breaks. Eukaryotic Rad51 proteins (Rad51sp or Rhp51 in fission yeast) are functional and structural homologs of bacterial RecA protein, an evolutionarily conserved protein that plays a key role in homologous pairing and strand exchange between homologous DNA molecules in vitro. Here we show that the fission yeast swi5+ gene, which was originally identified as a gene required for normal mating-type switching, encodes a protein conserved among eukaryotes and is involved in a previously uncharacterized Rhp51 (Rad51sp)-dependent recombination repair pathway that does not require the Rhp55/57 (Rad55/57sp) function. Protein interactions with both Swi5 and Rhp51 were found to be mediated by a domain common to Swi2 and Sfr1 (Swi five-dependent recombination repair protein 1, a previously uncharacterized protein with sequence similarity to the C-terminal part of Swi2). Genetic epistasis analyses suggest that the Swi5-Sfr1-Rhp51 interactions function specifically in DNA recombination repair, whereas the Swi5-Swi2-Rhp51 interactions may function, together with chromodomain protein Swi6 (HP1 homolog), in mating-type switching.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Base Sequence
  • Cloning, Molecular
  • Crosses, Genetic
  • DNA Primers
  • DNA Repair
  • DNA, Fungal / genetics
  • DNA, Fungal / radiation effects
  • Gamma Rays
  • Genomic Library
  • Humans
  • Molecular Sequence Data
  • Recombinant Proteins / metabolism
  • Recombination, Genetic / genetics*
  • Schizosaccharomyces / genetics*
  • Schizosaccharomyces pombe Proteins / genetics*
  • Schizosaccharomyces pombe Proteins / metabolism*
  • Schizosaccharomyces pombe Proteins / radiation effects
  • Sequence Alignment
  • Sequence Homology, Amino Acid
  • Sequence Homology, Nucleic Acid
  • Ultraviolet Rays


  • DNA Primers
  • DNA, Fungal
  • Recombinant Proteins
  • Schizosaccharomyces pombe Proteins
  • Sfr1 protein, S pombe
  • Swi5 protein, S pombe

Associated data

  • GENBANK/AB089498
  • GENBANK/AB089499
  • GENBANK/AB089500