Two different Swi5-containing protein complexes are involved in mating-type switching and recombination repair in fission yeast.
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.
Akamatsu
Yufuko
Y
Graduate School of Integrated Science, Yokohama City University, 1-7-29, Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan.
Dziadkowiec
Dorota
D
Ikeguchi
Mitsunori
M
Shinagawa
Hideo
H
Iwasaki
Hiroshi
H
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D003433:Crosses, Genetic; D017931:DNA Primers; D004260:DNA Repair; D004271:DNA, Fungal / Q000235:genetics / Q000528:radiation effects; D005720:Gamma Rays; D015698:Genomic Library; D006801:Humans; D008969:Molecular Sequence Data; D011994:Recombinant Proteins / Q000378:metabolism; D011995:Recombination, Genetic / Q000235:genetics*; D012568:Schizosaccharomyces / Q000235:genetics*; D029702:Schizosaccharomyces pombe Proteins / Q000235:genetics* / Q000378:metabolism* / Q000528:radiation effects; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid; D014466:Ultraviolet Rays
D017931:DNA Primers; D004271:DNA, Fungal; D011994:Recombinant Proteins; D029702:Schizosaccharomyces pombe Proteins; C514357:Sfr1 protein, S pombe; C483769:Swi5 protein, S pombe