快速40Sスキャニングと,真核細胞の翻訳初期におけるmRNA構造による制御

Jinfan Wang¹, Byung-Sik Shin², Carlos Alvarado¹

¹Department of Structural Biology, Stanford University School of Medicine, Stanford, CA, USA.

Cell

|November 5, 2022

まとめ

ユカリオット 43S 初期複合体は mRNA 5 をスキャンする.

科学分野:

分子生物学
生物化学
遺伝学

背景:

ユカリオット43S前始動複合体 (PIC) がメッセンジャーRNA (mRNA) 5' 未翻訳領域 (UTR) をスキャンして正しい開始コドンを特定するメカニズムは完全に理解されていません.
この過程を理解することは,トランスレーションレベルでの遺伝子発現の調節を解読するのに極めて重要です.

研究の目的:

酵母 43S PICの結合,スキャン,および 60S リボソームサブユニットの mRNAへの結合のダイナミクスをリアルタイムで直接観察し,特徴づけること.
トランスレーション開始時のスタートコドン選択を調節する開始因子とRNA構造の役割を解明する.

主な方法:

単一分子光スペクトロスコピーは,個々の酵母43S PICのmRNAの行動を追跡するために使用されました.
スキャニングダイナミクスに対するATP水解とRNA二次構造の影響を調査した.

主要な成果:

43S PICとmRNAの結合は,eIF4Aのような開始因子によって媒介される,遅い,ATPに依存するプロセスである.
一旦結合すると,43Sのスキャニングは迅速 (約100ヌクレオチド/秒) で,リボソーム後負荷ヘリケーゼ活動から大きく独立して方向的に進行する.
RNAの二次構造は,特にスタートコドンの近くのヘアピンで,スキャニングリボソームが後方に移動し,再スキャニングが必要になります.

結論:

直接観察は,5' UTR構造と上流のスタートコドンが翻訳開始をどのように制御するかのメカニズム的枠組みを提供します.
この研究では,スキャニングリボソーム,mRNA特性,および初期因子の間の動的相互作用が,正確なスタートコドン認識を確保することを明らかにしています.

キーワード:

5′ UTR について RNAヘリコース RNA二次構造ダイナミクスユカリオットリボソーム近親性のスタートコドンスキャニング単分子光スペクトル翻訳開始翻訳規制

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