Spindle checkpoint activation at meiosis I advances anaphase II onset via meiosis-specific APC/C regulation.
During mitosis, the spindle assembly checkpoint (SAC) inhibits the Cdc20-activated anaphase-promoting complex/cyclosome (APC/C(Cdc20)), which promotes protein degradation, and delays anaphase onset to ensure accurate chromosome segregation. However, the SAC function in meiotic anaphase regulation is poorly understood. Here, we examined the SAC function in fission yeast meiosis. As in mitosis, a SAC factor, Mad2, delayed anaphase onset via Slp1 (fission yeast Cdc20) when chromosomes attach to the spindle improperly. However, when the SAC delayed anaphase I, the interval between meiosis I and II shortened. Furthermore, anaphase onset was advanced and the SAC effect was reduced at meiosis II. The advancement of anaphase onset depended on a meiosis-specific, Cdc20-related factor, Fzr1/Mfr1, which contributed to anaphase cyclin decline and anaphase onset and was inefficiently inhibited by the SAC. Our findings show that impacts of SAC activation are not confined to a single division at meiosis due to meiosis-specific APC/C regulation, which has probably been evolved for execution of two meiotic divisions.
Yamamoto
Ayumu
A
Department of Chemistry, Shizuoka University, Suruga-ku, Shizuoka 422-8529, Japan. sayamam@ipc.shizuoka.ac.jp
Kitamura
Kenji
K
Hihara
Daisuke
D
Hirose
Yukinobu
Y
Katsuyama
Satoshi
S
Hiraoka
Yasushi
Y
D000705:Anaphase / Q000235:genetics*; D064173:Anaphase-Promoting Complex-Cyclosome; D064199:Cdc20 Proteins; D064200:Cdh1 Proteins; D018797:Cell Cycle Proteins / Q000235:genetics; D020090:Chromosome Segregation / Q000235:genetics; D015966:Gene Expression Regulation, Fungal / Q000235:genetics; D018816:Genes, cdc / Q000502:physiology*; D064246:Mad2 Proteins; D008540:Meiosis / Q000235:genetics*; D009687:Nuclear Proteins / Q000235:genetics; D012568:Schizosaccharomyces / Q000235:genetics* / Q000378:metabolism; D029702:Schizosaccharomyces pombe Proteins / Q000235:genetics; D008941:Spindle Apparatus / Q000235:genetics* / Q000378:metabolism; D043743:Ubiquitin-Protein Ligase Complexes / Q000235:genetics*
D064199:Cdc20 Proteins; D064200:Cdh1 Proteins; D018797:Cell Cycle Proteins; D064246:Mad2 Proteins; D009687:Nuclear Proteins; D029702:Schizosaccharomyces pombe Proteins; C577696:mad2 protein, S pombe; C577587:mfr1 protein, S pombe; C577504:slp1 protein, S pombe; D043743:Ubiquitin-Protein Ligase Complexes; D064173:Anaphase-Promoting Complex-Cyclosome