mRNA adenosine methylase (MTA) deposits m6A on pri-miRNAs to modulate miRNA biogenesis in Arabidopsis thaliana

Bhat, Susheel Sagar; Bielewicz, Dawid; Gulanicz, Tomasz; Bodi, Zsuzsanna; Yu, Xiang; Anderson, Stephen J.; Szewc, Lukasz; Bajczyk, Mateusz; Dolata, Jakub; Grzelak, Natalia; Smolinski, Dariusz J.; Gregory, Brian D.; Fray, Rupert G.; Jarmolowski, Artur; Szweykowska-Kulinska, Zofia

Abstract

Copyright © 2020 the Author(s). Published by PNAS. In Arabidopsis thaliana, the METTL3 homolog, mRNA adenosine methylase (MTA) introduces N6-methyladenosine (m6A) into various coding and noncoding RNAs of the plant transcriptome. Here, we show that an MTA-deficient mutant (mta) has decreased levels of microRNAs (miRNAs) but accumulates primary miRNA transcripts (pri-miRNAs). Moreover, pri-miRNAs are methylated by MTA, and RNA structure probing analysis reveals a decrease in secondary structure within stem-loop regions of these transcripts in mta mutant plants. We demonstrate interaction between MTA and both RNA Polymerase II and TOUGH (TGH), a plant protein needed for early steps of miRNA biogenesis. Both MTA and TGH are necessary for efficient colocalization of the Microprocessor components Dicer-like 1 (DCL1) and Hyponastic Leaves 1 (HYL1) with RNA Polymerase II. We propose that secondary structure of miRNA precursors induced by their MTA-dependent m6A methylation status, together with direct interactions between MTA and TGH, influence the recruitment of Microprocessor to plant pri-miRNAs. Therefore, the lack of MTA in mta mutant plants disturbs pri-miRNA processing and leads to the decrease in miRNA accumulation. Furthermore, our findings reveal that reduced miR393b levels likely contributes to the impaired auxin response phenotypes of mta mutant plants.

Citation

Bhat, S. S., Bielewicz, D., Gulanicz, T., Bodi, Z., Yu, X., Anderson, S. J., …Szweykowska-Kulinska, Z. (2020). mRNA adenosine methylase (MTA) deposits m6A on pri-miRNAs to modulate miRNA biogenesis in Arabidopsis thaliana. Proceedings of the National Academy of Sciences, 117(35), 21785-21795. https://doi.org/10.1073/pnas.2003733117

• Journal Article Type: Article
• Acceptance Date: Jul 27, 2020
• Online Publication Date: Aug 17, 2020
• Publication Date: Sep 1, 2020
• Deposit Date: Aug 24, 2020
• Publicly Available Date: Sep 14, 2020
• Journal: Proceedings of the National Academy of Sciences of the United States of America
• Print ISSN: 0027-8424
• Electronic ISSN: 1091-6490
• Publisher: National Academy of Sciences
• Peer Reviewed: Peer Reviewed
• Volume: 117
• Issue: 35
• Pages: 21785-21795
• DOI: https://doi.org/10.1073/pnas.2003733117
• Keywords: Multidisciplinary
• Public URL: https://nottingham-repository.worktribe.com/output/4847008
• Publisher URL: https://www.pnas.org/content/117/35/21785