结合来自小鼠丸的帕奇丁piRNAs的MIWI内啡核酶的结构
Nicole Raad1, Carmen Fernandez-Rodriguez1, Radha Raman Pandey1
1Department of Molecular Biology, Science III, University of Geneva, 30 Quai Ernest-Ansermet, Geneva 1211, Switzerland.
Cell reports
|January 13, 2026
概括
与PIWI相互作用的RNAs (piRNAs) 指导PIWI蛋白质使转子子对生育进行沉默. MIWI-piRNA复杂结构揭示了piRNAs如何结合以及PIWI酶如何为作用做准备.
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:
- 与PIWI相互作用的RNAs (piRNAs) 对于通过沉默可转移元素来维持基因组稳定性至关重要.
- 它们的功能是指导PIWI内核酶到互补的标转录,主要是转位子RNA.
- 功能失调的piRNA通路与动物的不孕症和基因组不稳定性有关.
研究的目的:
- 从小鼠丸中确定MIWI-pachytene piRNA复合物的高分辨率结构.
- 阐明piRNA结合和PIWI蛋白激活的分子机制.
- 了解PIWI复合体如何区分导向RNA和向RNA,并适应不匹配.
主要方法:
- 使用冷电子显微镜 (cryo-EM) 来确定MIWI-pachytene piRNA复合物的结构.
- 在孤立的复合体上进行了生化和结构分析.
主要成果:
- 该结构揭示了持有piRNA的特定相互作用,包括识别第一个尿素.
- 导向RNA为最初的六个核酸采用了A形形态,从而促进了目标配对.
- PIWI通道比昆虫同类更宽,允许piRNA与目标不匹配.
- PIWI内核酶域处于不活跃状态,需要重新定位以进行催化.
- 在PIWI域中的一个保存的口袋表明GTSF1的结合部位,可能会激活酶.
结论:
- MIWI-piRNA复杂结构为piRNA加载和识别机制提供了洞察力.
- 结构特征解释了piRNA介导沉默中对不匹配的耐受性.
- 这些发现表明PIWI酶激活的机制涉及构造变化和与GTSF1.1.等辅助因子的相互作用.
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