人类 Argonaute 2 在靶 RNA 上具有多种反应途径。

Human Argonaute 2 Has Diverse Reaction Pathways on Target RNAs.

机构信息

Department of Physics and Astronomy, Seoul National University, Seoul 151-747, Republic of Korea; Institute of Applied Physics, Seoul National University, Seoul 151-747, Republic of Korea; National Center of Creative Research Initiatives, Seoul National University, Seoul 151-747, Republic of Korea.

Department of Biological Sciences, KI for the BioCentury, KAIST, Daejeon 305-338, Republic of Korea.

出版信息

Mol Cell. 2015 Jul 2;59(1):117-24. doi: 10.1016/j.molcel.2015.04.027.

DOI:10.1016/j.molcel.2015.04.027

PMID:26140367

Abstract

Argonaute is a key enzyme of various RNA silencing pathways. We use single-molecule fluorescence measurements to characterize the reaction mechanisms of the core-RISC (RNA-induced silencing complex) composed of human Argonaute 2 and a small RNA. We found that target binding of core-RISC starts at the seed region, resulting in four distinct reaction pathways: target cleavage, transient binding, stable binding, and Argonaute unloading. The target cleavage requires extensive sequence complementarity and dramatically accelerates core-RISC recycling. The stable binding of core-RISC is efficiently established with the seed match only, providing a potential explanation for the seed-match rule of miRNA (microRNA) target selection. Target cleavage on perfect-match targets sensitively depends on RNA sequences, providing an insight into designing more efficient siRNAs (small interfering RNAs).

摘要

Argonaute 是各种 RNA 沉默途径的关键酶。我们使用单分子荧光测量来表征由人 Argonaute 2 和小 RNA 组成的核心-RISC（RNA 诱导沉默复合物）的反应机制。我们发现，核心-RISC 的靶标结合始于种子区域，导致四个不同的反应途径：靶标切割、瞬时结合、稳定结合和 Argonaute 卸载。靶标切割需要广泛的序列互补性，并极大地加速了核心-RISC 的循环利用。核心-RISC 的稳定结合仅通过种子匹配即可有效地建立，这为 miRNA（microRNA）靶标选择的种子匹配规则提供了一个潜在的解释。完美匹配靶标的靶标切割对 RNA 序列敏感，这为设计更有效的 siRNA（小干扰 RNA）提供了一个思路。