RRC ID 20921
Author Nanbu T, Takahashi K, Murray JM, Hirata N, Ukimori S, Kanke M, Masukata H, Yukawa M, Tsuchiya E, Ueno M.
Title Fission yeast RecQ helicase Rqh1 is required for the maintenance of circular chromosomes.
Journal Mol. Cell. Biol.
Abstract Protection of telomeres protein 1 (Pot1) binds to single-stranded telomere overhangs and protects chromosome ends. RecQ helicases regulate homologous recombination at multiple stages, including resection, strand displacement, and resolution. Fission yeast pot1 and RecQ helicase rqh1 double mutants are synthetically lethal, but the mechanism is not fully understood. Here, we show that the synthetic lethality of pot1Δ rqh1Δ double mutants is due to inappropriate homologous recombination, as it is suppressed by the deletion of rad51(+). The expression of Rad51 in the pot1Δ rqh1Δ rad51Δ triple mutant, which has circular chromosomes, is lethal. Reduction of the expression of Rqh1 in a pot1 disruptant with circular chromosomes caused chromosome missegregation, and this defect was partially suppressed by the deletion of rad51(+). Taken together, our results suggest that Rqh1 is required for the maintenance of circular chromosomes when homologous recombination is active. Crossovers between circular monomeric chromosomes generate dimers that cannot segregate properly in Escherichia coli. We propose that Rqh1 inhibits crossovers between circular monomeric chromosomes to suppress the generation of circular dimers.
Volume 33(6)
Pages 1175-87
Published 2013-3
DOI 10.1128/MCB.01713-12
PII MCB.01713-12
PMID 23297345
PMC PMC3592020
MeSH Cell Death / genetics Chromosomes, Fungal / genetics* Chromosomes, Fungal / metabolism DNA Helicases / genetics* DNA Helicases / metabolism DNA Topoisomerases, Type I / genetics DNA Topoisomerases, Type I / metabolism Escherichia coli / genetics Escherichia coli / metabolism Homologous Recombination / genetics* Mutation Rad51 Recombinase / genetics Rad51 Recombinase / metabolism Schizosaccharomyces / enzymology* Schizosaccharomyces / genetics* Schizosaccharomyces / metabolism Schizosaccharomyces pombe Proteins / genetics* Schizosaccharomyces pombe Proteins / metabolism Telomere / genetics Telomere / metabolism Telomere-Binding Proteins / genetics Telomere-Binding Proteins / metabolism
IF 3.735
Times Cited 4
Yeast FY18537