7SWF

Cryo-EM structure of Arabidopsis Ago10-guide-target RNA complex in a central duplex conformation

Summary for 7SWF

• Entry DOI: 10.2210/pdb7swf/pdb
• EMDB information: 25446 25472
• Descriptor: Protein argonaute 10, RNA (5'-R(P*UP*GP*GP*AP*GP*UP*GP*UP*GP*AP*CP*AP*AP*UP*GP*GP*U)-3'), RNA (5'-R(P*CP*CP*AP*UP*UP*GP*UP*CP*AP*CP*AP*CP*UP*CP*CP*AP*A)-3'), ... (4 entities in total)
• Functional Keywords: mirna, sirna, rna silencing, argonaute, plant, gene regulation
• Biological source: Arabidopsis thaliana (thale cress); More
• Total number of polymer chains: 3
• Total formula weight: 123430.38

Authors

Xiao, Y.,MacRae, I.J. (deposition date: 2021-11-19, release date: 2022-08-03, Last modification date: 2025-05-21)

Primary citation

Xiao, Y.,MacRae, I.J.
The molecular mechanism of microRNA duplex selectivity of Arabidopsis ARGONAUTE10.
Nucleic Acids Res., 50:10041-10052, 2022

PubMed Abstract: Small RNAs (sRNAs), including microRNAs (miRNAs) and small interfering RNAs (siRNAs), are essential gene regulators for plant and animal development. The loading of sRNA duplexes into the proper ARGONAUTE (AGO) protein is a key step to forming a functional silencing complex. In Arabidopsis thaliana, the specific loading of miR166/165 into AGO10 (AtAGO10) is critical for the maintenance of the shoot apical meristem, the source of all shoot organs, but the mechanism by which AtAGO10 distinguishes miR166/165 from other cellular miRNAs is not known. Here, we show purified AtAGO10 alone lacks loading selectivity towards miR166/165 duplexes. However, phosphate and HSP chaperone systems reshape the selectivity of AtAGO10 to its physiological substrates. A loop in the AtAGO10 central cleft is essential for recognizing specific mismatches opposite the guide strand 3' region in miR166/165 duplexes. Replacing this loop with the equivalent loop from Homo sapiens AGO2 (HsAGO2) changes AtAGO10 miRNA loading behavior such that 3' region mismatches are ignored and mismatches opposite the guide 5' end instead drive loading, as in HsAGO2. Thus, this study uncovers the molecular mechanism underlying the miR166/165 selectivity of AtAGO10, essential for plant development, and provides new insights into how miRNA duplex structures are recognized for sRNA sorting.

PubMed: 35801914
DOI: 10.1093/nar/gkac571

Experimental method

ELECTRON MICROSCOPY (3.79 Å)