Monitoring the molecular dynamics in the assembly of ncRNA machinery

2018 Fiscal Year Final Research Report

• Project Area: Neo-taxonomy of noncoding RNAs
• Project/Area Number: 26113007
• 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: The University of Tokyo
• Principal Investigator: Tomari Yukihide 東京大学, 定量生命科学研究所, 教授 (90447368)
• Co-Investigator(Kenkyū-buntansha): 多田隈 尚史 大阪大学, 蛋白質研究所, 助教 (10339707)
• Research Collaborator: SASAKI Hiroshi ; YAO Chunyan ; TSUBOYAMA Kotaro ; MASUBUCHI Takeya
• Project Period (FY): 2014-07-10 – 2019-03-31
• Keywords: 一分子イメージング / RNA干渉 / Argonaute / RISC

Outline of Final Research Achievements

Using the effector complex of RNA interference, called "RISC," as a model system, we developed new techniques that can monitor the molecular dynamics of ncRNA machinery in a real-time and quantitative manner at the single-molecule level. We used these techniques to study the dynamic structural changes of Argonaute proteins, the core of RISC. We found that the structure of Argonaute, which is closed in the empty state, is first opened by helper factors. After incorporating the small RNAs, Argonaute takes a fixed, semi-open structure. Moreover, our data provided molecular insights into how RISC can recognize and cleave their targets so quickly and accurately. In conclusion, single-molecule imaging allowed us to uncover these detailed molecular mechanisms, which were not readily approachable by conventional biochemistry.

Free Research Field

RNA生物学

Academic Significance and Societal Importance of the Research Achievements

RNA干渉は、任意の遺伝子の発現を簡便にシャットダウンできるため、基礎生物学だけではなく、医薬への応用も進められているが、その分子レベルでの詳細なメカニズムはまだ完全に理解されているとは言えない。本研究によって、RISC形成や標的切断における律速段階を高い精度で同定し、それを突破するような配列デザインや化学修飾を行うことができれば、より高い効率で作用する小分子RNAの合理的設計が可能になることが期待される。