通过V型CRISPR转位子系统选择和重塑目标部位
Irma Querques1, Michael Schmitz1, Seraina Oberli1
1Department of Biochemistry, University of Zurich, Zurich, Switzerland.
Nature
|November 11, 2021
概括
研究人员揭示了由CRISPR相关的转位子引导DNA转位的机制. 结构和生化研究表明Cas12k如何引导DNA插入,使新的基因编辑工具成为可能.
科学领域:
- 分子生物学
- 遗传学
- 生物化学
背景情况:
- CRISPR-Cas系统提供了对移动基因元素的适应性免疫力.
- 类似Tn7的转子利用CRISPR系统 (I-F,I-B,V-K类型) 来进行RNA引导的DNA插入.
- 通过V-K型CRISPR关联的转位子对RNA导向的DNA转位的分子机制尚不清楚.
研究的目的:
- 通过V-K型CRISPR相关的转位子阐明RNA导向的DNA转位的分子机制.
- 通过Cas12k指导RNA复合体确定目标DNA识别的结构基础.
- 了解TnsC,TnsB和TniQ在转化过程中的作用.
主要方法:
- 低温电子显微镜 (cryo-EM) 用于确定Cas12k导向RNA向DNA复合体和DNA结合的TnsC丝的结构.
- 在体内转换测试以验证结构发现.
- 生物化学实验调查蛋白质相互作用和酶活动.
主要成果:
- 低温EM结构揭示了复杂的导向RNA架构和Cas12k对RNA导向DNA识别的关键相互作用.
- 这种TnsC丝组是依赖ATP的,并诱导DNA双重重组.
- 在ATP水解时,TniQ限制了TnsC的聚合,而TnsB则触发了TnsC丝的分解,从而促进了转子体的插入.
结论:
- 通过Cas12k的RNA导向标选择启动了TnsC聚合和DNA重塑.
- 这一过程为TnsB创造了一个平台,以催化特定站点的转子插入.
- 这些发现为开发CRISPR相关的转位子作为可编程的基因插入工具提供了见解.
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