结构化的mRNA通过与核糖体平台的结合来调节翻译启动
Stefano Marzi1, Alexander G Myasnikov, Alexander Serganov
1IGBMC (Institute of Genetics and of Molecular and Cellular Biology), Department of Structural Biology and Genomics, Illkirch, F-67404 France.
Cell
|September 25, 2007
概括
传递 RNA (mRNA) 中的调节元素可以通过阻断蛋白质合成来控制基因表达. 低温电子显微镜可视化了mRNA结构如何阻断,然后从核糖体释放以调节翻译.
科学领域:
- 分子生物学分子生物学
- 结构生物学 结构生物学
- 遗传学 是一个遗传学.
背景情况:
- 基因表达在多个层面上受到严格监管.
- 翻译启动是基因表达的一个关键控制点.
- 传递 RNA (mRNA) 的 5' 未翻译区域 (5' UTR) 内的调控元素可以影响翻译启动.
研究的目的:
- 想象5' UTR mRNA元素调节翻译启动的结构机制.
- 了解抑制蛋白如何与mRNA和核糖体相互作用以控制翻译.
- 为了确定对调节性mRNA元素的核糖体上的潜在的通用结合点.
主要方法:
- 使用冷电子显微镜 (cryo-EM) 来捕获核糖体复合体的快照.
- 在停滞 (压抑) 和活跃 (未折叠的mRNA) 状态中可视化了核糖体复合体.
- 进行了比较结构和序列分析.
主要成果:
- 冷EM揭示了折叠的mRNA结构如何与抑制蛋白S15结合,通过阻止开始子进入P位来阻断核糖体.
- 在抑制器释放时,mRNA展开并进入核糖体mRNA通道,允许开始翻译.
- 建议在核糖体上保留一个"30S平台",作为结合调节性5'mRNA元素的通用部位.
结论:
- 调控性5' UTR mRNA结构可以暂时阻断核糖体,提供一种控制基因表达的机制.
- 核糖体拥有一个专门的平台,用于在翻译预启动过程中容纳和调节这些mRNA结构.
- 这种机制突出了对转录后基因调节的保存策略.
相关概念视频
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First, the initiator tRNA must be selected from the pool of elongator tRNAs by eukaryotic initiation factor 2 (eIF2). The initiator tRNA (Met-tRNAi) has conserved sequence elements including modified bases at...
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