Molecular basis for asymmetry sensing of siRNAs by the Drosophila Loqs-PD/Dcr-2 complex in RNA interference
| Autor: | Ralf Stehle, Michael Sattler, Oliver F. Lange, Christoph Kreutz, Arie Geerlof, Klaus Förstemann, Christoph Hartlmüller, Thomas Kern, Romy Böttcher, Stefan Kunzelmann, Stephanie Fesser, Michael Andreas Juen, Jan-Niklas Tants, Christoph H. Wunderlich |
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| Rok vydání: | 2017 |
| Předmět: |
Ribonuclease III
0301 basic medicine Small interfering RNA Base pair RNA-induced silencing complex Biology 03 medical and health sciences Protein Domains Structural Biology RNA interference microRNA Genetics Animals Drosophila Proteins RNA Small Interfering Cells Cultured RNA Double-Stranded Schneider 2 cells RNA-Binding Proteins RNA Molecular biology Cell biology 030104 developmental biology Argonaute Proteins Thermodynamics Drosophila RNA Interference RNA Helicases Protein Binding Binding domain |
| Zdroj: | Nucleic Acids Res. 45, 12536-12550 (2017) Nucleic Acids Research |
| ISSN: | 1362-4962 0305-1048 |
| DOI: | 10.1093/nar/gkx886 |
| Popis: | RNA interference defends against RNA viruses and retro-elements within an organism's genome. It is triggered by duplex siRNAs, of which one strand is selected to confer sequence-specificity to the RNA induced silencing complex (RISC). In Drosophila, Dicer-2 (Dcr-2) and the double-stranded RNA binding domain (dsRBD) protein R2D2 form the RISC loading complex (RLC) and select one strand of exogenous siRNAs according to the relative thermodynamic stability of base-pairing at either end. Through genome editing we demonstrate that Loqs-PD, the Drosophila homolog of human TAR RNA binding protein (TRBP) and a paralog of R2D2, forms an alternative RLC with Dcr-2 that is required for strand choice of endogenous siRNAs in S2 cells. Two canonical dsRBDs in Loqs-PD bind to siRNAs with enhanced affinity compared to miRNA/miRNA* duplexes. Structural analysis, NMR and biophysical experiments indicate that the Loqs-PD dsRBDs can slide along the RNA duplex to the ends of the siRNA. A moderate but notable binding preference for the thermodynamically more stable siRNA end by Loqs-PD alone is greatly amplified in complex with Dcr-2 to initiate strand discrimination by asymmetry sensing in the RLC. |
| Databáze: | OpenAIRE |
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