转录增加了核蛋白组合的合作性
Margaret L Rodgers1, Sarah A Woodson1
1T.C. Jenkins Department of Biophysics, Johns Hopkins University, Baltimore, MD 21218, USA.
Cell
|November 26, 2019
概括
在rRNA转录过程中开始组建核糖体. 早期蛋白S4与前核糖体RNA的结合是暂时的,但与其他核糖体蛋白稳定,使得有效的共转录组合.
科学领域:
- 分子生物学
- 生物化学
- 遗传学
背景情况:
- 核糖体合成对细胞功能至关重要,涉及核糖体RNA (rRNA) 的转录及其与核糖体蛋白质的组合.
- 协同转录组合,即与转录同时发生组合,是核糖体生物发生的一个关键过程.
- 在转录过程中与新生的rRNA结合的精确顺序和动态尚未完全理解.
研究的目的:
- 在转录过程中可视化和理解核糖体蛋白-RNA复合体的实时动态.
- 研究早期组装蛋白的结合动力学,如S4,到新生前-16S rRNA.
- 阐明促进高效共转录核糖体组合的机制.
主要方法:
- 开发一个单分子平台,同时监测转录和蛋白质与延长RNA的关联.
- 对新生rRNA转录的蛋白质结合事件的实时观察.
- 分析其他核糖体蛋白对早期组合因子结合稳定性的影响.
主要成果:
- 早期组装蛋白 uS4 对新合成的 pre-16S rRNA 呈现短暂的结合,这表明在转录过程中与非原生 RNA 折叠存在挑战.
- 在存在其他结合上游和下游的核糖体蛋白质时,US4的稳定结合显著增强.
- 这些额外的蛋白质促进生产性组装中间体的形成,促进早期的稳定复合体的形成.
结论:
- 协同转录的核糖体组合是一个动态的过程,涉及序列蛋白质采样而不是严格的5'到3'梯度.
- 通过多种蛋白质对延长RNA进行动态采样,有助于克服异质RNA折叠,防止组装瓶.
- 这种机制确保在转录时间窗口内有效启动核糖体组合,并且可能是转录合RNP组合的一般特征.
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