Masliah, Gregoire, Maris, Christophe, Koenig, Sebastian L.B., Yulikov, Maxim, Aeschimann, Florian, Malinowska, Anna L., Mabille, Julie, Weiler, Jan, Holla, Andrea, Hunziker, Juerg, Meisner Kober, Nicole-Claudia, Schuler, Benjamin, Jeschke, Gunnar and Allain, Frederic H.-T. (2018) Structural basis of siRNA recognition by TRBP double-stranded RNA binding domains. The EMBO Journal, 37. ISSN 0261-41891460-20750261-41891460-2075

Abstract

The accurate cleavage of pre-micro(mi)RNAs by Dicer and mi/siRNA guide strand selection are important steps in forming the RNA-induced silencing complex (RISC). The role of Dicer binding partner TRBP in these processes remains poorly understood. Here, we solved the solution structure of the two N-terminal dsRNA binding domains (dsRBDs) of TRBP in complex with a functionally asymmetric siRNA using NMR, EPR, and single-molecule spectroscopy. We find that siRNA recognition by the dsRBDs is not sequence-specific but rather depends on the RNA shape. The two dsRBDs can swap their binding sites, giving rise to two equally populated, pseudo-symmetrical complexes, showing that TRBP is not a primary sensor of siRNA asymmetry. Using our structure to model a Dicer-TRBP-siRNA ternary complex, we show that TRBP's dsRBDs and Dicer's RNase III domains bind a canonical 19 base pair siRNA on opposite sides, supporting a mechanism whereby TRBP influences Dicer-mediated cleavage accuracy by binding the dsRNA region of the pre-miRNA during Dicer cleavage.

Item Type:	Article
Date Deposited:	09 Mar 2018 00:45
Last Modified:	09 Mar 2018 00:45
URI:	https://oak.novartis.com/id/eprint/33231