在I-F3型CRISPR-Cas效应器的PAM远部位进行序列结构重组,使RNA引导DNA转换成为可能
Kazuki Ishihara1, Shunsuke Matsumoto1, Christoph Gerle2
1Department of Bioscience and Biotechnology, Graduate School of Bioresource and Bioenvironmental Sciences, Kyushu University, Fukuoka 819-0395, Japan.
Nucleic acids research
|January 7, 2026
概括
与CRISPR相关的转体质 (CAST) 使用RNA引导的DNA结合进行插入. 新的结构揭示了Cas8/5如何识别原空间体相邻动机 (PAM) 并曲DNA,指导转位.
科学领域:
- 分子生物学分子生物学
- 遗传学 是一个遗传学.
- 微生物学 微生物学
背景情况:
- 与CRISPR相关的转体子 (CAST) 是 prokaryotes 中发现的移动遗传元素.
- 通过CRISPR-Cas效应器系统和转换机制,CAST集成到特定的DNA目标中.
- CAST集成的确切机制,特别是目标DNA识别和DNA曲,仍然不清楚.
研究的目的:
- 阐明 I-F3 类型 CAST DNA 目标识别和转换许可的基础结构机制.
- 了解Cas8/5和TniQ在原空间细胞相邻基因 (PAM) 识别和DNA操纵中的作用.
主要方法:
- 来自Vibrio parahaemolyticus的三种电子显微镜 (cryo-EM) 结构的目标DNA结合型I-F3 TniQ-Cascade复合体被确定.
- 结构分析的重点是Cas8/5,TniQ和目标DNA之间的相互作用,包括PAM识别和DNA曲.
主要成果:
- 这些结构揭示了Cas8/5如何识别PAM,识别了在-2位置偏好cytidine的关键残留物.
- 在PAM近位点观察到不匹配耐受性.
- 通过Cas8/5和TniQ的形状变化介导的PAM-遥远部位的DNA曲,被证明可以引导DNA向转位机制方向.
结论:
- 这些发现为管理I-F3 CAST类型转换许可的动态重排提供了原子层面的见解.
- 了解这些机制对于破译移动遗传元素动态至关重要,并对基因组工程应用产生影响.
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