고려대학교 생명과학대학 생명과학부/ 대학원 분자생명과학과

Abstract

To achieve global view of miRNA-target interactions in living tissues, a genome-wide method of mapping RNA-protein interactions in vivo (HITS-CLIP) has been applied to Argonaute (Ago), a core protein in RISC (RNA-induced silencing complex) and  generated Ago-miRNA-mRNA ternary maps in mouse brain. Not all Ago mRNA bindings correspond to well-known seed pairing rules, leading to the discovery of a new rule following “pivot pairing” and the mode of target recognition, termed “transitional nucleation”. Further supported by recent structural studies of human Ago-miRNA complex, transitional nucleation model promoted to design a novel modification for small interfering RNAs (siRNAs) to completely eliminate its miRNA-like off-targeting while it conserves near-perfect on-target activity. Specifically, introducing the modification to PCSK9 siRNAs, therapeutically developed for lowering plasma cholesterol, could abolish unanticipated deleterious off-target phenotypes. Ago HITS-CLIP provides a general platform to understand functional miRNA binding sites in vivo, discovering transitional nucleation mode of target recognition and leading to develop a chemical method that harnesses specificity of siRNAs..