Structural Insights Into Rna Cleavage By Piwi Argonaute Zhiqing Li Qikui Xu Jing Zhong Yan Zhang Tianxiang Zhang Xiaoze Ying Xiaoli Lu Xiaoyi Li Li Wan Junchao Xue Jing Huang Ying Zhen Zhao Zhang Jianping Wu Enzhi Shen by Zhiqing Li & Qikui Xu & Jing Zhong & Yan Zhang & Tianxiang Zhang & Xiaoze Ying & Xiaoli Lu & Xiaoyi Li & Li Wan & Junchao Xue & Jing Huang & Ying Zhen & Zhao Zhang & Jianping Wu & En-zhi Shen 101038/S41586024084381 instant download after payment.

Argonaute proteins are categorized into AGO and PIWI clades. Across most animal Check for updatesspecies, AGO-clade proteins are widely expressed in various cell types, and regulate normal gene expression1. By contrast, PIWI-clade proteins predominantly function during gametogenesis to suppress transposons and ensure fertility1,2. Both clades use nucleic acid guides for target recognition by means of base pairing, crucial for initiating target silencing, often through direct cleavage. AGO-clade proteins use a narrow channel to secure a tight guide–target interaction3. By contrast, PIWI proteins feature a wider channel that potentially allows mismatches during pairing, broadening target silencing capability4,5. However, the mechanism of PIWI-mediated target cleavage remains unclear. Here we demonstrate that after target binding, PIWI proteins undergo a conformational change from an ‘open’ state to a ‘locked’ state, facilitating base pairing and enhancing target cleavage efciency. This transition involves narrowing of the binding channel and repositioning of the PIWI-interacting RNA–target duplex towards the MID-PIWI lobe, establishing extensive contacts for duplex stabilization. During this transition, we also identify an intermediate ‘comma-shaped’ conformation, which might recruit GTSF1, a known auxiliary protein that enhances PIWI cleavage activity6. GTSF1 facilitates the transition to the locked state by linking the PIWI domain to the RNA duplex, thereby expediting the conformational change critical for efcient target cleavage. These fndings explain the molecular mechanisms underlying PIWI–PIWI-interacting RNA complex function in target RNA cleavage, providing insights into how dynamic conformational changes from PIWI proteins coordinate cofactors to safeguard gametogenesis.