Intertwined pathways for Argonaute-mediated microRNA biogenesis in Drosophila

Although Dicer is essential for general microRNA (miRNA) biogenesis, vertebrate mir-451 is Dicer independent. Instead, its short pre-miRNA hairpin is ‘sliced’ by Ago2, then 3′-resected into mature miRNAs. Here, we show that Drosophila cells and animals generate functional small RNAs from mir-451-typ...

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Main Authors:	Yang, Jr-Shiuan, Smibert, Peter, Westholm, Jakub O., Jee, David, Maurin, Thomas, Lai, Eric C.
Format:	Online
Language:	English
Published:	Oxford University Press 2014
Online Access:	https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3919586/

id	pubmed-3919586
recordtype	oai_dc
spelling	pubmed-39195862014-02-10 Intertwined pathways for Argonaute-mediated microRNA biogenesis in Drosophila Yang, Jr-Shiuan Smibert, Peter Westholm, Jakub O. Jee, David Maurin, Thomas Lai, Eric C. RNA Although Dicer is essential for general microRNA (miRNA) biogenesis, vertebrate mir-451 is Dicer independent. Instead, its short pre-miRNA hairpin is ‘sliced’ by Ago2, then 3′-resected into mature miRNAs. Here, we show that Drosophila cells and animals generate functional small RNAs from mir-451-type precursors. However, their bulk maturation arrests as Ago-cleaved pre-miRNAs, which mostly associate with the RNAi effector AGO2. Routing of pre-mir-451 hairpins to the miRNA effector AGO1 was inhibited by Dicer-1 and its partner Loqs. Loss of these miRNA factors promoted association of pre-mir-451 with AGO1, which sliced them and permitted maturation into ∼23–26 nt products. The difference was due to the 3′ modification of single-stranded species in AGO2 by Hen1 methyltransferase, whose depletion permitted 3′ trimming of Ago-cleaved pre-miRNAs in AGO2. Surprisingly, Nibbler, a 3′–5′ exoribonuclease that trims ‘long’ mature miRNAs in AGO1, antagonized miR-451 processing. We used an in vitro reconstitution assay to identify a soluble, EDTA-sensitive activity that resects sliced pre-miRNAs in AGO1 complexes. Finally, we use deep sequencing to show that depletion of dicer-1 increases the diversity of small RNAs in AGO1, including some candidate mir-451-like loci. Altogether, we document unexpected aspects of miRNA biogenesis and Ago sorting, and provide insights into maturation of Argonaute-cleaved miRNA substrates. Oxford University Press 2014-02 2013-11-12 /pmc/articles/PMC3919586/ /pubmed/24220090 http://dx.doi.org/10.1093/nar/gkt1038 Text en © The Author(s) 2013. Published by Oxford University Press. http://creativecommons.org/licenses/by/3.0/ This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited.
repository_type	Open Access Journal
institution_category	Foreign Institution
institution	US National Center for Biotechnology Information
building	NCBI PubMed
collection	Online Access
language	English
format	Online
author	Yang, Jr-Shiuan Smibert, Peter Westholm, Jakub O. Jee, David Maurin, Thomas Lai, Eric C.
spellingShingle	Yang, Jr-Shiuan Smibert, Peter Westholm, Jakub O. Jee, David Maurin, Thomas Lai, Eric C. Intertwined pathways for Argonaute-mediated microRNA biogenesis in Drosophila
author_facet	Yang, Jr-Shiuan Smibert, Peter Westholm, Jakub O. Jee, David Maurin, Thomas Lai, Eric C.
author_sort	Yang, Jr-Shiuan
title	Intertwined pathways for Argonaute-mediated microRNA biogenesis in Drosophila
title_short	Intertwined pathways for Argonaute-mediated microRNA biogenesis in Drosophila
title_full	Intertwined pathways for Argonaute-mediated microRNA biogenesis in Drosophila
title_fullStr	Intertwined pathways for Argonaute-mediated microRNA biogenesis in Drosophila
title_full_unstemmed	Intertwined pathways for Argonaute-mediated microRNA biogenesis in Drosophila
title_sort	intertwined pathways for argonaute-mediated microrna biogenesis in drosophila
description	Although Dicer is essential for general microRNA (miRNA) biogenesis, vertebrate mir-451 is Dicer independent. Instead, its short pre-miRNA hairpin is ‘sliced’ by Ago2, then 3′-resected into mature miRNAs. Here, we show that Drosophila cells and animals generate functional small RNAs from mir-451-type precursors. However, their bulk maturation arrests as Ago-cleaved pre-miRNAs, which mostly associate with the RNAi effector AGO2. Routing of pre-mir-451 hairpins to the miRNA effector AGO1 was inhibited by Dicer-1 and its partner Loqs. Loss of these miRNA factors promoted association of pre-mir-451 with AGO1, which sliced them and permitted maturation into ∼23–26 nt products. The difference was due to the 3′ modification of single-stranded species in AGO2 by Hen1 methyltransferase, whose depletion permitted 3′ trimming of Ago-cleaved pre-miRNAs in AGO2. Surprisingly, Nibbler, a 3′–5′ exoribonuclease that trims ‘long’ mature miRNAs in AGO1, antagonized miR-451 processing. We used an in vitro reconstitution assay to identify a soluble, EDTA-sensitive activity that resects sliced pre-miRNAs in AGO1 complexes. Finally, we use deep sequencing to show that depletion of dicer-1 increases the diversity of small RNAs in AGO1, including some candidate mir-451-like loci. Altogether, we document unexpected aspects of miRNA biogenesis and Ago sorting, and provide insights into maturation of Argonaute-cleaved miRNA substrates.
publisher	Oxford University Press
publishDate	2014
url	https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3919586/
_version_	1612056774225952768

Intertwined pathways for Argonaute-mediated microRNA biogenesis in Drosophila

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