Single-molecule fluorescence measurements reveal the reaction mechanisms of the core-RISC,composed of human Argonaute 2 and a guide RNA |
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Authors: | Myung Hyun Jo Ji-Joon Song Sungchul Hohng |
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Affiliation: | 1.Department of Physics and Astronomy;2.Institute of Applied Physics;3.National Center of Creative Research Initiatives;4.Department of Biophysics and Chemical Biology, Seoul National University, Seoul 08826;5.Department of Biological Sciences, KAIST, Daejeon 34141, Korea |
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Abstract: | In eukaryotes, small RNAs play important roles in both gene regulation and resistance to viral infection. Argonaute proteins have been identified as a key component of the effector complexes of various RNA-silencing pathways, but the mechanistic roles of Argonaute proteins in these pathways are not clearly understood. To address this question, we performed single-molecule fluorescence experiments using an RNA-induced silencing complex (core-RISC) composed of a small RNA and human Argonaute 2. We found that target binding of core-RISC starts at the seed region of the guide RNA. After target binding, four distinct reactions followed: target cleavage, transient binding, stable binding, and Argonaute unloading. Target cleavage required extensive sequence complementarity and accelerated core-RISC dissociation for recycling. In contrast, the stable binding of core-RISC to target RNAs required seed-match only, suggesting a potential explanation for the seed-match rule of microRNA (miRNA) target selection. [BMB Reports 2015; 48(12): 643-644] |
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Keywords: | Argonaute miRNA siRNA Single-molecule FRET |
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