人間 miRISC の組立と機能における段階的移行
Jessica Sheu-Gruttadauria1, Ian J MacRae1
1Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA.
Cell
|March 27, 2018
まとめ
マイクロプロセッサ複合体 (miRISC) は,タンパク質の相互作用によって相分離滴を形成する. この凝縮は標的メッセンジャーRNA (mRNA) のデデニレーションを加速し,遺伝子の静止のための新しいメカニズムを明らかにします.
科学分野:
- 分子生物学
- 生物化学
- RNA 生物学
背景:
- マイクロプロセッサ複合体 (miRISC) は,マイクロRNA (miRNA) による遺伝子調節に不可欠である.
- miRISCの物理的な構造と組み立ては,ほとんど定義されていない.
- miRISCの物理的性質を理解することは,その規制メカニズムの解読に鍵となる.
研究 の 目的:
- 人間のmiRISCの物理的性質と組み立てを調査する
- miRISC形成におけるタンパク質相互作用の役割を明らかにする.
- miRISCの凝縮がRNA処理に及ぼす機能的影響を決定する.
主な方法:
- コア miRISCタンパク質Argonaute2 (Ago2) とTNRC6Bを用いた試験
- miRISCのドロップレット形成を観察するための生細胞イメージング.
- デデニレーション因子の募集と標的RNAの結合の生化学的分析
主要な成果:
- 人間のmiRISCのコアコンポーネントであるAgo2とTNRC6Bは,in vitroおよび細胞で液体-液体相分離を受けます.
- 段階分離は,TNRC6BのGW豊富なドメインとAgo2のPIWIドメインの間の多価相互作用によって引き起こされる.
- miRISC滴はデデニレーション因子を誘導し,標的mRNAのデデニレーションを加速する.
結論:
- タンパク質による相分離はヒトの miRISC の基本的な特性です.
- miRISCの凝縮は,効率的な標的mRNAデデニレーションと遺伝子サイレンスを促進します.
- このメカニズムは,miRISCが様々なmRNA基板をどのように処理するかについての洞察を提供します.
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