Septin2 is modified by SUMOylation and required for chromosome congression in mouse oocytes.
In mitosis, centrosomes nucleate microtubules that capture the sister kinetochores of each chromosome to facilitate chromosome congression. In contrast, during meiosis chromosome congression on the acentrosomal spindle is driven primarily by movement of chromosomes along laterally associated microtubule bundles. Previous studies have indicated that septin2 is required for chromosome congression and cytokinesis in mitosis, we therefore asked whether perturbation of septin2 would impair chromosome congression and cytokinesis in meiosis. We have investigated its expression, localization and function during mouse oocyte meiotic maturation. Septin2 was modified by SUMO-1 and its levels remained constant from GVBD to metaphase II stages. Septin2 was localized along the entire spindle at metaphase and at the midbody in cytokinesis. Disruption of septins function with an inhibitor and siRNA caused failure of the metaphase I /anaphase I transition and chromosome misalignment but inhibition of septins after the metaphase I stage did not affect cytokinesis. BubR1, a core component of the spindle checkpoint, was labeled on misaligned chromosomes and on chromosomes aligned at the metaphase plate in inhibitor-treated oocytes that were arrested in prometaphase I/metaphase I, suggesting activation of the spindle assembly checkpoint. Taken together, our results demonstrate that septin2 plays an important role in chromosome congression and meiotic cell cycle progression but not cytokinesis in mouse oocytes.
Zhu
Jin-Liang
JL
State Key Laboratory of Reproductive Biology, Chinese Academy of Sciences, Beijing, China.
Lin
Sheng-Li
SL
Li
Mo
M
Ouyang
Ying-Chun
YC
Hou
Yi
Y
Schatten
Heide
H
Sun
Qing-Yuan
QY
D000818:Animals; D020090:Chromosome Segregation / Q000187:drug effects; D002875:Chromosomes / Q000502:physiology*; D048749:Cytokinesis; D005260:Female; D008540:Meiosis; D008677:Metaphase; D051379:Mice; D015739:Nocodazole / Q000494:pharmacology; D009865:Oocytes / Q000187:drug effects / Q000378:metabolism*; D017239:Paclitaxel / Q000494:pharmacology; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000378:metabolism; D025842:SUMO-1 Protein / Q000378:metabolism*; D058112:Septins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D008941:Spindle Apparatus / Q000502:physiology; D058207:Sumoylation
D034741:RNA, Small Interfering; D025842:SUMO-1 Protein; D058112:Septins; D017239:Paclitaxel; D015739:Nocodazole