Roles of CDK1 phosphorylation of condensin I in mitotic chromosome assembly

2019 Fiscal Year Final Research Report

• Project/Area Number: 17K15070
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Molecular biology
• Research Institution: Institute of Physical and Chemical Research
• Principal Investigator: Tane Shoji 国立研究開発法人理化学研究所, 開拓研究本部, 特別研究員 (40770516)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Keywords: コンデンシン / 染色体形成 / CDK1 / リン酸化制御 / タンパク質修飾

Outline of Final Research Achievements

It remained unknown which subunits of condensin I (and which sites of them) are phosphorylated and how phosphorylation of those individual sites regulates condensin I’ s functions. To address these questions, we expressed and purified a mutant holo-complex harboring alanine mutations in 20 the potential CDK1 phosphorylation sites (20A mutant), and examined their ability to assemble chromosomes by adding them back into a Xenopus egg extract depleted of endogenous condensin complexes. We found that the 20A mutant was still able to produce fibrous structures although their morphology was poorer than that supported by the wild type complex. Our data suggest that phosphorylation of additional CDK1 sites is required for complete assembly of mitotic chromosomes.

Free Research Field

染色体構築

Academic Significance and Societal Importance of the Research Achievements

CDK1依存的なコンデンシン I の活性調節については培養細胞や酵母を使った遺伝学的な解析においても報告されている。しかしこうした変異体を用いた in vivo での遺伝学的な解析では、染色体分離異常を介した細胞死が引き起こされるため 、染色体の形態変化 の詳細を解析することが難しい。本研究で用いる組換えコンデンシン複合体とカエル卵抽出液とを組み合わせた方法は細胞死の問題を回避でき、かつ経時的に染色体構築のしくみについての知見を得ることができる。