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細菌における転写-翻訳結合と衝突の構造的基礎

Michael William Webster^1,2,3,4, Maria Takacs^1,2,3,4, Chengjin Zhu^1,2,3,4

¹Department of Integrated Structural Biology, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), 67404 Illkirch, France.

Science (New York, N.Y.)

|August 22, 2020

まとめ

プロカリオットメッセンジャーRNA (mRNA) は転写時に翻訳され,エクスプレソームを形成する. Cryo-EM構造は,転写因子NusGがリボソームとRNAポリメラーゼ (RNAP) を結合し,遺伝子発現を調整する方法を示しています.

科学分野:

分子生物学
構造生物学
微生物学

背景:

プロカリオットメッセンジャーRNA (mRNA) は同時に転写と翻訳をします.
この過程で,リボソームの翻訳とRNAポリメラーゼ (RNAP) の複合体であるエクスプレソームが形成されます.
エクスプレソームの組み立てのメカニズムと遺伝子発現への影響はほとんど不明である.

研究の目的:

エクスプレソームアセンブリの構造的基礎を解明する.
プロカリオットにおける転写と翻訳の連携を理解する.
エクスプレソーム複合体の異なる状態を特徴づける.

主な方法:

高解像度構造を決定するために,冷凍電子顕微鏡 (cryo-EM) が使用されました.
解き放たれた,結合された,衝突した状態を捕捉した.
分析はリボソームとRNAPの相互作用に重点を置いた.

主要な成果:

転写因子NusGはリボソームとRNAPの相互作用を安定させ,ブリッジを形成する.
mRNAの長さは,リボソームとRNAPチャネルが並ぶ"衝突した"状態につながります.
衝突した状態では,NusGによるリンクが切断されています.

結論:

エクスプレソーム形成に関する構造的な洞察は,転写と翻訳のカップリングのメカニズムを明らかにします.
NusGは結合したトランスクリプション・トランスレーション機構の安定化に重要な役割を果たします.
これらの発見は,プロカリオットの遺伝子発現の調節を理解するための枠組みを提供する.

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