The structural landscape of Microprocessor-mediated processing of pri-let-7 miRNAs

Garg, Ankur, Shang, Renfu, Cvetanovic, Todor, Lai, Eric C, Joshua-Tor, Leemor (October 2024) The structural landscape of Microprocessor-mediated processing of pri-let-7 miRNAs. Molecular Cell. S1097-2765(24)00741. ISSN 1097-2765

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Abstract

MicroRNA (miRNA) biogenesis is initiated upon cleavage of a primary miRNA (pri-miRNA) hairpin by the Microprocessor (MP), composed of the Drosha RNase III enzyme and its partner DGCR8. Multiple pri-miRNA sequence motifs affect MP recognition, fidelity, and efficiency. Here, we performed cryoelectron microscopy (cryo-EM) and biochemical studies of several let-7 family pri-miRNAs in complex with human MP. We show that MP has the structural plasticity to accommodate a range of pri-miRNAs. These structures revealed key features of the 5' UG sequence motif, more comprehensively represented as the "flipped U with paired N" (fUN) motif. Our analysis explains how cleavage of class-II pri-let-7 members harboring a bulged nucleotide generates a non-canonical precursor with a 1-nt 3' overhang. Finally, the MP-SRSF3-pri-let-7f1 structure reveals how SRSF3 contributes to MP fidelity by interacting with the CNNC motif and Drosha's Piwi/Argonaute/Zwille (PAZ)-like domain. Overall, this study sheds light on the mechanisms for flexible recognition, accurate cleavage, and regulated processing of different pri-miRNAs by MP.

Item Type: Paper
Subjects: bioinformatics
bioinformatics > genomics and proteomics > genetics & nucleic acid processing > DNA, RNA structure, function, modification
bioinformatics > genomics and proteomics > genetics & nucleic acid processing
bioinformatics > genomics and proteomics
bioinformatics > genomics and proteomics > genetics & nucleic acid processing > DNA, RNA structure, function, modification > RNAi
CSHL Authors:
Communities: CSHL labs > Joshua-Tor lab
SWORD Depositor: CSHL Elements
Depositing User: CSHL Elements
Date: 1 October 2024
Date Deposited: 15 Oct 2024 13:37
Last Modified: 20 Nov 2024 16:09
PMCID: PMC11560618
Related URLs:
URI: https://repository.cshl.edu/id/eprint/41706

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