Rad51-dependent aberrant chromosome structures at telomeres and ribosomal DNA activate the spindle assembly checkpoint.
The spindle assembly checkpoint (SAC) monitors defects in kinetochore-microtubule attachment or lack of tension at kinetochores and arrests cells at prometaphase. In fission yeast, the double mutant between pot1Δ and the helicase-dead point mutant of the RecQ helicase Rqh1 gene (rqh1-hd) accumulates Rad51-dependent recombination intermediates at telomeres and enters mitosis with those intermediates. Here, we found that SAC-dependent prometaphase arrest occurred more frequently in pot1Δ rqh1-hd double mutants than in rqh1-hd single mutants. SAC-dependent prometaphase arrest also occurred more frequently in rqh1-hd single mutants after cells were released from DNA replication block compared to the rqh1-hd single mutant in the absence of exogenous insult to the DNA. In both cases, Mad2 foci persisted longer than usual at kinetochores, suggesting a defect in kinetochore-microtubule attachment. In pot1Δ rqh1-hd double mutants and rqh1-hd single mutants released from DNA replication block, SAC-dependent prometaphase arrest was suppressed by the removal of the recombination or replication intermediates. Our results indicate that the accumulation of recombination or replication intermediates induces SAC-dependent prometaphase arrest, possibly by affecting kinetochore-microtubule attachment.
Department of Molecular Biotechnology, Graduate School of Advanced Sciences of Matter, Hiroshima University, Higashi-Hiroshima, Japan.
Akemi
A
Nakano
Kenta
K
Masuda
Taisuke
T
Hiromoto
Katsunori
K
Takahashi
Yoshitake
Y
Matsumoto
Ahmed G K
AG
Habib
Ahmed G G
AG
Darwish
Masashi
M
Yukawa
Eiko
E
Tsuchiya
Masaru
M
Ueno
D000818:Animals; D018797:Cell Cycle Proteins / Q000235:genetics; D020090:Chromosome Segregation / Q000235:genetics; D015825:Chromosomes, Fungal / Q000235:genetics; D004260:DNA Repair / Q000235:genetics; D004275:DNA, Ribosomal / Q000235:genetics*; D018816:Genes, cdc / Q000235:genetics*; D018386:Kinetochores / Q000378:metabolism; D059566:M Phase Cell Cycle Checkpoints / Q000235:genetics; D008938:Mitosis / Q000235:genetics / Q000502:physiology; D009154:Mutation / Q000235:genetics; D051135:Rad51 Recombinase / Q000235:genetics*; D012568:Schizosaccharomyces / Q000235:genetics*; D029702:Schizosaccharomyces pombe Proteins / Q000235:genetics* / Q000378:metabolism; D008941:Spindle Apparatus / Q000235:genetics*; D016615:Telomere / Q000235:genetics*
D018797:Cell Cycle Proteins; D004275:DNA, Ribosomal; D029702:Schizosaccharomyces pombe Proteins; D051135:Rad51 Recombinase