Bub1 prevents chromosome misalignment and precocious anaphase during mouse oocyte meiosis.
In mitosis the checkpoint proteins ensure faithful chromosome segregation by delaying onset of anaphase until all sister chromatids align at the metaphase plate of the bipolar spindle correctly. In the present study we blocked the function of Bub1 during meiosis by microinjecting anti-Bub1 specific antibody into cytoplasm of mouse oocytes, and found that depletion of Bub1 induced evident cyclin B degradation and precocious anaphase onset. Bub1 suppression also overrode the checkpoint-dependent cell cycle arrest provoked by a low dosage of nocodazole. Furthermore, Bub1 depletion induced a significantly higher percentage of oocytes with misaligned chromosomes. In addition, we depicted the localization dynamics of Bub1 in response to spindle damage and its relationship with microtubules and chromosomes, providing further evidence for Bub1's role as a spindle checkpoint protein. Our data suggest that Bub1 is a critical spindle checkpoint protein that regulates accurate chromosome alignment and homolog disjunction in mammalian oocyte meiosis.
Yin
Shen
S
State Key Laboratory of Reproductive Biology, Institute of Zoology, Beijing, China.
Wang
Qiang
Q
Liu
Jing-He
JH
Ai
Jun-Shu
JS
Liang
Cheng-Guang
CG
Hou
Yi
Y
Chen
Da-Yuan
DY
Schatten
Heide
H
Sun
Qing-Yuan
QY
D000705:Anaphase / Q000235:genetics*; D000818:Animals; D000906:Antibodies / Q000494:pharmacology; D002453:Cell Cycle / Q000235:genetics; D020090:Chromosome Segregation / Q000235:genetics*; D002875:Chromosomes / Q000235:genetics / Q000378:metabolism*; D019926:Cyclin B / Q000378:metabolism; D056744:Cyclin B1; D005260:Female; D018816:Genes, cdc / Q000502:physiology; D008540:Meiosis / Q000235:genetics*; D051379:Mice; D009865:Oocytes / Q000166:cytology / Q000378:metabolism*; D009866:Oogenesis / Q000235:genetics; D011494:Protein Kinases / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases; D008941:Spindle Apparatus / Q000235:genetics / Q000378:metabolism
D000906:Antibodies; C534700:Ccnb1 protein, mouse; D019926:Cyclin B; D056744:Cyclin B1; D011494:Protein Kinases; C584281:Bub1 protein, mouse; C090464:Bub1 spindle checkpoint protein; D017346:Protein Serine-Threonine Kinases