Analysis of the mechanism underlying G1/S checkpoint threshold by CDK-Cyclin

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K16050
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 43010:Molecular biology-related
• Research Institution: National Institute for Basic Biology
• Principal Investigator: Goto Yuhei 基礎生物学研究所, 定量生物学研究部門, 助教 (50814620)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: 定量イメージング / CDK / サイクリン / 分裂酵母 / 光遺伝学 / PhyB / Cry2 / FRET

Outline of Final Research Achievements

Eukaryotic cells sense the environmental and their own situation to decide whether or not to proliferate. Cell cycle checkpoints are used to arrest the cell cycle according to the situations. However, it remains elusive how these checkpoints convert continuous (analog) external stimuli into binary (digital) information.
In this study, we aimed to elucidate the quantitative threshold mechanism by observing the dynamics of CDK, a master regulator of the cell cycle, at the single-cell level. We succeeded in developing a novel CDK activity sensor that can measure CDK activity in living cells. We also succeeded in artificially manipulation of the cell cycle checkpoint by directly perturbing CDKs through optogenetics.
Throughout this study, it is suggested that the fission yeast cell cycle integrates various inputs into CDK activity and that the final CDK activity, rather than the expression level of a particular factor, is responsible for the substantial threshold determination.

Free Research Field

細胞生物学

Academic Significance and Societal Importance of the Research Achievements

これまで細胞周期の研究の多くは、生化学によるスナップショット、かつ細胞集団の平均的な挙動しか観測してこなかった。また、細胞周期は個々の細胞で独立しているために、薬剤などを用いて細胞周期を同調する必要があった。本研究で開発したCDK活性センサーを用いると、1細胞でのCDKの活性を経時的に、薬剤による同調無しに追うことが可能となり、細胞周期の中でのCDK活性動態を高時間分解能で追うことが可能となる。また、細胞周期への摂動も光遺伝学を用いることにより、顕微鏡観察下で任意のタイミングで操作することが可能となった。これらの技術をさらに応用し生体内での細胞周期制御が可能となることが期待される。