Control of chromosome functions by axis-loop structure (chromosome 3D) during meiosis

2019 Fiscal Year Final Research Report

• Project Area: Chromosome Orchestration System
• Project/Area Number: 15H05973
• Research Category: Grant-in-Aid for Scientific Research on Innovative Areas (Research in a proposed research area)
• Allocation Type: Single-year Grants
• Review Section: Biological Sciences
• Research Institution: Osaka University
• Principal Investigator: Shinohara Akira 大阪大学, 蛋白質研究所, 教授 (00252578)
• Co-Investigator(Kenkyū-buntansha): 篠原 美紀 近畿大学, 農学部, 教授 (80335687) ; 吉田 佳世 大阪市立大学, 大学院医学研究科, 准教授 (30311921)
• Project Period (FY): 2015-06-29 – 2020-03-31
• Keywords: 染色体 / 減数分裂 / 染色体OS / 配偶子 / コヒーシン / 異数体

Outline of Final Research Achievements

Sister chromatid cohesion (SCC) is essential for proper chromosome segregation in mitosis and meiosis. During meiosis, a meiosis-specific cohesin promotes not only the segregation of chromosomes at both meiosis I and II but also chromosome dynamics in prophase I. In budding yeast meiosis, it is known that the removal of cohesin from chromosome arms by the cleavage of Rec8, a meiosis-specific α-kleisin subunit, triggers the segregation of homologous chromosomes during meiosis I. We found that large amounts of Rec8, thus meiosis-specific cohesion, is removed from chromosomes, particularly from chromosome arms in the late prophase I of the yeast. This removal of Rec8 is cleavage-independent. This meiosis-specific prophase pathway requires the phosphorylation of cohesin components, Rec8 and Rad61/Wpl1(Wapl) by PLK and DDK kinases. We will discuss the biological significance for the removal of cohesin from chromosome arms in late prophase I.

Free Research Field

分子生物学

Academic Significance and Societal Importance of the Research Achievements

染色体の部位特異的な構造変換が機能的な分化を生み出すという新しい概念を提唱し、核機能の理解と言った基礎生物学の進展に貢献した。減数分裂期の染色体分配の欠損は染色体の数の異常を持つ異数体形成、つまり、ダウン症などの遺伝病や不妊、流産の原因になることが知られている。特に、今回の発見により卵子の老化による流産にはコヒーシンの欠損が関わるという考えを支持し、今後、診断や治療などの発展に大きく貢献すると考えられる。