C型肝炎ウイルスのような内部リボソームのエントリーサイトは,eIF3を移動させ,40Sサブユニットにアクセスします
Yaser Hashem1, Amedee des Georges, Vidya Dhote
11] Howard Hughes Medical Institute (HHMI), Department of Biochemistry and Molecular Biophysics, Columbia University, New York City, New York 10032, USA [2] Department of Biochemistry and Molecular Biophysics, Columbia University, New York City, New York 10032, USA.
Nature
|November 5, 2013
まとめ
C型肝炎ウイルス (HCV) と古典豚熱ウイルス (CSFV) は,内部リボソームエントリーサイト (IRES) をトランスレーションに使用します. この研究では,eIF3とCSFV IRESの相互作用が40Sサブユニットとの結合を防止し,ウイルスのmRNA翻訳を好むことを明らかにしました.
科学分野:
- 分子生物学は分子生物学である.
- ウイルス学 ウイルス学 ウイルス学
- 構造生物学 構造生物学とは
背景:
- C型肝炎ウイルス (HCV) と古典的豚熱ウイルス (CSFV) は,内部リボソームエントリーサイト (IRES) を利用して,キャップ独立の翻訳を開始します.
- これらのIRESは,エウカリオット発起因子 (eIF) のサブセットを必要とし,40Sリボソームサブユニットと相互作用して発起複合体を形成します.
- トランスレーション開始におけるeIF3とHCV型IRESの相互作用の具体的な役割は,ほとんど不明のままでした.
研究 の 目的:
- 翻訳開始時にeIF3がHCV型IRESと相互作用する機能を明らかにする.
- CSFV IRESに結合するeIF3の構造的基礎と,リボソーム複合体の形成に与える影響を調査する.
主な方法:
- 低温電子顕微鏡 (cryo-EM) を使用して,eIF3とCSFV IRESを含む40Sリボソーム複合体の構造を決定しました.
- 複合体内のIRESとeIF3のリボソーム位置と相互作用の分析.
主要な成果:
- CSFV IRESは,HCV IRESと同様に40Sサブユニットと結合します.
- eIF3は,40Sサブユニット上のカノニカル結合部位から異動し,IRES領域IIIの頂点領域と直接相互作用する.
- この相互作用は,eIF3が40Sサブユニットと関連付けられることを防止し,結合サイトの競争を回避します.
結論:
- HCV型IRESとeIF3の間の特定の相互作用は,翻訳開始を規制する上で重要な役割を果たしています.
- eIF3の異位は,40Sサブユニット結合の競争を緩和し,43S初期化前の複合体の形成を減少させます.
- このメカニズムは,細胞のmRNAよりもウイルスのmRNAの翻訳を好む.
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