mRNA adenosine methylase (MTA) deposits m 6 A on pri-miRNAs to modulate miRNA biogenesis in Arabidopsis thaliana

Significance Recently N 6 -methyladenosine (m 6 A) methylation has emerged as a biological process with significant impact on cellular functions. However, almost all the research regarding m 6 A methylation has been based on mRNAs. In our research, we focus on how m 6 A methylation affects microRNA (miRNA) biogenesis in Arabidopsis . In brief, we show that m 6 A methylation is necessary to maintain proper levels of mature miRNAs as well as their precursors. m 6 A mark affects pri-miRNA secondary structures and affects the recruitment of the Microprocessor to pri-miRNAs. We also demonstrate the interactions of MTA (m 6 A writer) with other proteins involved in miRNA biogenesis, namely RNA Polymerase II and TOUGH. Our study provides evidence of the role played by m 6 A in plant miRNA biogenesis.