Neurodevelopmental disorder-linked Argonaute mutations permit delayed RISC formation and unusual shortening of miRNAs by 3′→5′ trimming

• 成果类型: Article
• 署名作者: Savidge, Andrew; Zhang, Huaqun; Adhav, Vishal Annasaheb; Kehling, Audrey C.; Sim, Geunyoung; Shen, Zhangfei; Fu, Tian- Min; Nakanishi, Kotaro
• 署名单位: University System of Ohio; Ohio State University; University System of Ohio; Ohio State University; University System of Ohio; Ohio State University; University System of Ohio; Ohio State University; University System of Ohio; Ohio State University; University System of Ohio; Ohio State University; James Cancer Hospital & Solove Research Institute; University System of Ohio; Ohio State University; University of Massachusetts System; UMass Chan Medical School; University of Massachusetts Worcester
• 刊物名称: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• ISSN/ISSBN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.2524644122
• 发表日期: 2025-11-18
• 页码: e2524644122
• 关键词: RNAi; noncoding rnas; neurodevelopmental disorder

摘要

Mutations in Argonaute proteins (AGOs) cause Argonaute syndrome, a neurodevelopmental disorder (NDD), yet the underlying molecular mechanism remains unclear. We determined cryo-electron microscopy (cryo-EM) structures of wild-type (WT) AGO1 and the recurrent, severe causative Delta F180 mutant. AGO1(Delta F180) unexpectedly rearranges the hydrophobic core of the L1 domain to preserve the overall RNA-induced silencing complexes (RISC) architecture and recognize guide RNAs similarly to WT. Functionally, the mutant binds target RNAs like WT but more frequently retains passenger strands, implicating a defect in RISC assembly. Biochemical assays of Delta F180 and L190P mutants revealed normal duplex loading but impaired passenger ejection, exposing guide 3 ' ends to 3 '-> 5 ' exonucleases and generating abnormally short similar to 11-nucleotide RNAs. In cells, AGO1(Delta F180), AGO1(G199S), and corresponding AGO2 mutants likewise produced truncated guides. Together, these findings support a model in which defective passenger ejection underlies the pathology of AGO-associated NDDs by rendering microRNAs bound to AGO syndrome mutants susceptible to aberrant 3 ' trimming.