DEAD-Box Protein Dhh1pは,コドン最適性を監視することによって,mRNAの分解と翻訳をカップル化する
Aditya Radhakrishnan1, Ying-Hsin Chen2, Sophie Martin2
1Program in Molecular Biophysics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Department of Molecular Biology and Genetics, Howard Hughes Medical Institute, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA.
Cell
|September 20, 2016
まとめ
DEAD-boxタンパク質 Dhh1pはリボソームの速度を検知するセンサーとして機能し,特に分解に最適でないコドンを持つmRNAを標的にする. このメカニズムは,トランスレーションの延長率とmRNA崩壊経路を結びつける.
科学分野:
- 分子生物学
- 遺伝学
- 生物化学
背景:
- mRNAの半減期は,コドンに依存するトランスレーションの速度によって大きく影響されます.
- 翻訳的伸縮とmRNAの衰退の間の正確なコミュニケーションメカニズムは,ほとんど不明のままである.
研究 の 目的:
- コドン最適性を感知するDEAD-boxタンパク質 Dhh1pの役割とそのmRNA崩壊への影響を調査する.
- mRNAのリボソーム速度がmRNAの分解経路にどのように影響するか解明する.
主な方法:
- コドン最適度と Dhh1pの存在との関係でmRNAの分解率を分析する.
- Dhh1pとmRNAの関連性を評価する生化学実験を行う.
- Dhh1p過剰発現を用いて,コドン最適度が異なるmRNAのリボソーム蓄積を調査する.
- Dhh1pとリボソームの間の in vivo 物理的相互作用を検証する.
主要な成果:
- 非最適のコドンによる翻訳延伸が遅いmRNAは,Dh1pに依存した方法で特異的に分解されます.
- Dhh1pは,最適でないコドン選択を持つmRNAに優先的に結合する.
- これらのmRNAの分解は,ゆっくり動くリボソームの数に敏感です.
- Dhh1pの過剰発現は,低コードン最適性のmRNAとコードンにリボソームの蓄積を引き起こします.
- DHh1pは体内でリボソームと物理的に相互作用する.
結論:
- Dhh1pはリボソーム速度のセンサーとして機能し,mRNAの運命を翻訳効率と結びつける.
- このメカニズムは,抑制およびその後の衰退のために最適でないコドン利用を持つmRNAをターゲットにします.
- この発見は,トランスレーション制御とmRNAの安定性を結びつける新しい経路を示しています.
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