Unique roles of kinetochores in oocytes

2018 Fiscal Year Final Research Report

• Project/Area Number: 16H06161
• Research Category: Grant-in-Aid for Young Scientists (A)
• Allocation Type: Single-year Grants
• Research Field: Molecular biology
• Research Institution: Institute of Physical and Chemical Research
• Principal Investigator: Kitajima Tomoya 国立研究開発法人理化学研究所, 生命機能科学研究センター, チームリーダー (00376641)
• Project Period (FY): 2016-04-01 – 2019-03-31
• Keywords: 卵母細胞 / 動原体 / 染色体分配

Outline of Final Research Achievements

This study investigated oocyte-specific roles for kinetochores in meiosis I of oocytes. In animals, unlike somatic cells and spermatocytes, oocytes lack centrosomes. To reveal how the acentrosomal spindle forms during meiosis in oocytes, we investigated the process using mouse oocytes as a model. First, we showed that meiosis I underwent a relatively long process of spindle bipolarization, whereas meiosis II rapidly formed a bipolar spindle. Second, we showed that meiosis I required functional kinetochores for spindle bipolarization, whereas meiosis II did not. Third, we showed that meiosis II cytoplasm enabled meiosis I chromosomes to form a bipolar spindle independently of functional kinetochores. Forth, we identified kinetochore-enriched microtubule regulators, which were exploited to simulation approaches. These results indicate that an oocyte-specific function of kinetochores enables meiosis I-specific mode of acentrosomal spindle bipolarization.

Free Research Field

細胞生物学

Academic Significance and Societal Importance of the Research Achievements

マウス卵母細胞において動原体が果たす役割の一つは、非中心体性の紡錘体を両極化させることであることが分かった。ヒト卵母細胞では紡錘体の両極化の失敗が卵子の染色体数異常の原因となることが知られている。今後さらに動原体が紡錘体を両極化させる分子機構を明らかにすることで、流産などの主要な原因の一つである卵子の染色体数異常の理解につながる可能性がある。