The catalytic activity of microRNA Argonautes plays a modest role in microRNA star strand destabilization in C. elegans

Kotagama, Kasuen, Grimme, Acadia L, Braviner, Leah, Yang, Bing, Sakhawala, Rima M, Yu, Guoyun, Benner, Lars Kristian, Joshua-Tor, Leemor, McJunkin, Katherine (January 2024) The catalytic activity of microRNA Argonautes plays a modest role in microRNA star strand destabilization in C. elegans. bioRxiv. (Submitted)

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Abstract

Many Argonaute proteins can cleave RNA (“slicing”) as part of the microRNA-induced silencing complex (miRISC), even though miRNA-mediated target repression is generally independent of target cleavage. Here we use genome editing in C. elegans to examine the role of miRNA-guided slicing in organismal development. In contrast to previous work, slicing-inactivating mutations did not interfere with normal development when introduced by CRISPR. We find that unwinding and decay of miRNA star strands is weakly defective in the absence of slicing, with the largest effect observed in embryos. Argonaute-Like Gene 2 (ALG-2) is more dependent on slicing for unwinding than ALG-1. The miRNAs that displayed the greatest (albeit minor) dependence on slicing for unwinding tend to form stable duplexes with their star strand, and in some cases, lowering duplex stability alleviates dependence on slicing. Gene expression changes were consistent with negligible to moderate loss of function for miRNA guides whose star strand was upregulated, suggesting a reduced proportion of mature miRISC in slicing mutants. While a few miRNA guide strands are reduced in the mutant background, the basis of this is unclear since changes were not dependent on EBAX-1, a factor in the Target-Directed miRNA Degradation (TDMD) pathway. Overall, this work defines a role for miRNA Argonaute slicing in star strand decay; future work should examine whether this role could have contributed to the selection pressure to conserve catalytic activity of miRNA Argonautes across the metazoan phylogeny.

Item Type:	Paper
Subjects:	bioinformatics organism description > animal > C elegans 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 organism description > animal bioinformatics > genomics and proteomics > genetics & nucleic acid processing > DNA, RNA structure, function, modification > miRNA bioinformatics > genomics and proteomics > genetics & nucleic acid processing > DNA, RNA structure, function, modification > miRNA
CSHL Authors:	Joshua-Tor, Leemor Braviner, Leah
Communities:	CSHL labs > Joshua-Tor lab School of Biological Sciences > Publications
SWORD Depositor:	CSHL Elements
Depositing User:	CSHL Elements
Date:	9 January 2024
Date Deposited:	25 Jan 2024 14:02
Last Modified:	29 Feb 2024 16:54
Related URLs:	Publisher
URI:	https://repository.cshl.edu/id/eprint/41421

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