Download MendeleyDICER cleavage fidelity is governed by 5'-end binding pockets.
Ngo, M.K., Le, C.T., Nguyen, T.A.(2026) Nature
- PubMed: 41781616
- DOI: https://doi.org/10.1038/s41586-026-10211-5
- Primary Citation of Related Structures:
21CB, 21CN, 21CQ, 9V42, 9V43 - PubMed Abstract:
RNA interference (RNAi) depends on DICER, an essential enzyme that processes RNA precursors into small regulatory RNAs. DICER cleaves RNA precursors according to the 5'-end counting rule, in which RNA length is measured from the 5'-end 1-3 . Previous work proposed a single 5'-end binding pocket that disfavours guanosine (5'-G), leading to cleavage inaccuracies 4 . Here we show that 5'-G promotes precise cleavage for many substrates. Using massively parallel dicing assays and cryo-electron microscopy, we identify a conserved guanosine-favoured (G-favoured) binding pocket in DICER, distinct from the previously described uridine-favoured (U-favoured) pocket. Together, these pockets influence the alignment between 21-nucleotide and 22-nucleotide cleavage registers, expanding the mechanism of small-RNA biogenesis in metazoan DICERs. We also find that conflicts between 5'-end binding and RNA-motif recognition can trigger RNA conformational adjustments that preserve accurate cleavage-site selection. In addition, conformational adjustments of the double-stranded RNA-binding domain (dsRBD) and PAZ domain help to align substrates with the catalytic centres for precise double-strand cleavage. These results show that the DICER cleavage mechanism integrates dual 5'-end binding pockets, RNA-motif influence and domain motions, advancing our understanding of microRNA biogenesis.
- Division of Life Science, Hong Kong University of Science and Technology, Hong Kong, China.
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