通过dCas12f-σE-RNAP复合体进行RNA引导转录的结构基础
Renjian Xiao1, Florian T Hoffmann2,3, Dan Xie1
1Department of Biological Sciences, Purdue University, West Lafayette, IN, USA.
Nature
|March 4, 2026
概括
这项研究揭示了CRISPR-Cas系统 (dCas12f-σE) 如何激活细菌基因转录. 由RNA引导的DNA结合招募RNA聚合酶,通过与传统促进体识别不同的新机制启动转录.
科学领域:
- 分子生物学分子生物学
- 微生物学 微生物学
- 生物化学 生化学
背景情况:
- RNA导向蛋白调节生物系统中的基因表达.
- 与CRISPR相关的蛋白质和TnpB是已知的细菌转录调节剂.
- 通过核酶死Cas12f (dCas12f) 和西格玛因子 (σE) 激活转录的机制以前是未知的.
研究的目的:
- 阐明由dCas12f-σE系统介导的RNA引导转录启动的分子机制.
- 确定dCas12f-σE与RNA聚合酶 (RNAP) 和DNA的相互作用的结构基础.
主要方法:
- 使用冷电子显微镜 (cryo-EM) 来确定高分辨率结构.
- 捕获了dCas12f-σE-RNAP全酶复合物的多个结构和组成状态.
- 结构分析的重点是RNA引导的DNA结合及其对转录启动的影响.
主要成果:
- 这项研究揭示了一种新的RNA引导转录启动模式.
- 通过dCas12f进行RNA引导的DNA结合有助于 σE-RNAP的招募.
- 转录启动发生在R循环的下游,CRISPR-Cas准取代了-35元素识别和改变了-10元素稳定.
结论:
- 这项工作为RNA引导转录的意想不到机制提供了高分辨率的结构洞察力.
- 这些发现扩大了对细菌基因调节和CRISPR-Cas功能的理解.
- 这项研究为开发可编程的转录控制系统开辟了新的可能性.
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