トランスクリプションはリボ核タンパク質組成の協力性を高める
Margaret L Rodgers1, Sarah A Woodson1
1T.C. Jenkins Department of Biophysics, Johns Hopkins University, Baltimore, MD 21218, USA.
Cell
|November 26, 2019
まとめ
リボソームの組み立てはrRNAの転写で始まる. 初期のタンパク質 uS4 のリボソーム前RNAへの結合は一時的ですが,他のリボソームタンパク質と安定し,効率的な共転写アセンブリを可能にします.
科学分野:
- 分子生物学
- 生物化学
- 遺伝学
背景:
- リボソーム合成は,リボソームRNA (rRNA) の転写とリボソームタンパク質との組み立てを含む細胞機能にとって極めて重要です.
- コトランスクリプションアセンブリは,トランスクリプションと同時に行われるが,リボソーム生物生成の重要なプロセスである.
- 転写中の新生rRNAへのリボソームタンパク質結合の正確な順序とダイナミクスは完全に理解されていません.
研究 の 目的:
- 転写中のリボソームタンパク質-RNA複合体の形成のリアルタイムダイナミクスを視覚化および理解する.
- uS4などの初期アセンブリタンパク質の新生前-16S rRNAへの結合運動を調査する.
- 効率的な共転写リボソームの組み立てを促進するメカニズムを解明する.
主な方法:
- 転写とタンパク質の結合を延長RNAで同時に監視できる単一分子プラットフォームの開発.
- 新生rRNAトランスクリプトへのタンパク質結合のリアルタイム観察.
- 初期の組み立て因子の結合安定性に対する他のリボソームタンパク質の影響の分析.
主要な成果:
- 初期のアセンブリタンパク質 uS4 は,新たに合成された前-16S rRNA に一時的に結合し,転写中に非ネイティブ RNA の折りたたみとの課題を示唆する.
- uS4の安定結合は,他のリボソームタンパク質が上流と下流に結合している場合に顕著に強化されます.
- これらの追加のタンパク質は,生産性のある組み立ての中間物質の形成を促進し,早期に安定した複合体の形成を促進します.
結論:
- 同転写リボソーム組成は,厳格な5'から3'のグラデントではなく,連続したタンパク質サンプリングを含むダイナミックなプロセスです.
- 多数のタンパク質による伸びるRNAのダイナミックサンプリングは,不均一なRNAの折り畳みを克服し,組み立てのボトルネックを防ぐのに役立ちます.
- このメカニズムは,転写時間ウィンドウ内のリボソームアセンブリの効率的な開始を保証し,転写結合RNPアセンブリの一般的な特徴である可能性があります.
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