Structural bases of transcriptional regulation by chromatin conformation

2019 Fiscal Year Final Research Report

• Project/Area Number: 19K21175
• Project/Area Number (Other): 18H06041 (2018)
• Research Category: Grant-in-Aid for Research Activity Start-up
• Allocation Type: Multi-year Fund (2019); Single-year Grants (2018)
• Review Section: 0701:Biology at molecular to cellular levels, and related fields
• Research Institution: The University of Tokyo
• Principal Investigator: Nozawa Kayo 東京大学, 定量生命科学研究所, 助教 (10808554)
• Project Period (FY): 2018-08-24 – 2020-03-31
• Keywords: クロマチン / 転写 / RNAポリメラーゼ

Outline of Final Research Achievements

Mediator binds to the promoter through the C-terminal region of RNA polymerase II (Pol II CTD) and presents the CTD to TFIIH kinase to induce transcription. In this study, we constructed a fusion protein of Med-complex and CTD and performed small-angle X-ray scattering analysis to visualize the structural transformation of Mediator that occurred at the initiation of transcription. It was observed that CTD detach from Mediator upon phosphorylation. Furthermore, to test if Mediator stimulates Pol II CTD phosphorylation by TFIIH kinase, Pol II and TFIIH kinase were successfully expressed, purified, and subjected to the kinase assay. It was observed that the recombinantly prepared Mediator protein increased the phosphorylation efficiency by 10-fold.

Free Research Field

構造生物学

Academic Significance and Societal Importance of the Research Achievements

ヒトを構成する約2万種類のタンパク質の情報はDNAに保存され、Pol IIの働きでmRNAに転写されることで初めて、その設計図として機能する。しかし、設計図は必要な時に作られなければ細胞の秩序が壊れ、生命活動を維持することはできない。このPol IIの機能の「オン」、「オフ」を制御しているのが、Medによって誘起されるクロマチンの構造変換やPol II CTDのリン酸化パターンである。本研究で得られた成果をさらに生化学実験にフィードバックすることで、転写が関わる細胞分裂の異常や癌化についても、新たな知見が得られると期待される。