title: N6-methyladenosine marks primary microRNAs for processing.
abstract: The first step in the biogenesis of microRNAs is the processing of primary microRNAs (pri-miRNAs) by the microprocessor complex, composed of the RNA-binding protein DGCR8 and the type III RNase DROSHA. This initial event requires recognition of the junction between the stem and the flanking single-stranded RNA of the pri-miRNA hairpin by DGCR8 followed by recruitment of DROSHA, which cleaves the RNA duplex to yield the pre-miRNA product. While the mechanisms underlying pri-miRNA processing have been determined, the mechanism by which DGCR8 recognizes and binds pri-miRNAs, as opposed to other secondary structures present in transcripts, is not understood. Here we find in mammalian cells that methyltransferase-like 3 (METTL3) methylates pri-miRNAs, marking them for recognition and processing by DGCR8. Consistent with this, METTL3 depletion reduced the binding of DGCR8 to pri-miRNAs and resulted in the global reduction of mature miRNAs and concomitant accumulation of unprocessed pri-miRNAs. In vitro processing reactions confirmed the sufficiency of the N(6)-methyladenosine (m(6)A) mark in promoting pri-miRNA processing. Finally, gain-of-function experiments revealed that METTL3 is sufficient to enhance miRNA maturation in a global and non-cell-type-specific manner. Our findings reveal that the m(6)A mark acts as a key post-transcriptional modification that promotes the initiation of miRNA biogenesis.
authors: Laboratory of Systems Cancer Biology, Rockefeller University, 1230 York Avenue, New York, New York 10065, USA.
authors: Claudio R
authors: CR
authors: Alarcón
authors: Laboratory of Systems Cancer Biology, Rockefeller University, 1230 York Avenue, New York, New York 10065, USA.
authors: Hyeseung
authors: H
authors: Lee
authors: Laboratory of Systems Cancer Biology, Rockefeller University, 1230 York Avenue, New York, New York 10065, USA.
authors: Hani
authors: H
authors: Goodarzi
authors: Laboratory of Systems Cancer Biology, Rockefeller University, 1230 York Avenue, New York, New York 10065, USA.
authors: Nils
authors: N
authors: Halberg
authors: Laboratory of Systems Cancer Biology, Rockefeller University, 1230 York Avenue, New York, New York 10065, USA.
authors: Sohail F
authors: SF
authors: Tavazoie
mesh_terms: D000241:Adenosine / Q000031:analogs & derivatives* / Q000378:metabolism; D001483:Base Sequence; D002460:Cell Line; D005786:Gene Expression Regulation; D006801:Humans; D008745:Methylation; D008780:Methyltransferases / Q000172:deficiency / Q000378:metabolism; D035683:MicroRNAs / Q000737:chemistry* / Q000378:metabolism*; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D012323:RNA Processing, Post-Transcriptional; D016601:RNA-Binding Proteins / Q000378:metabolism; D013379:Substrate Specificity
chemical_list: C474043:DGCR8 protein, human; D035683:MicroRNAs; D016601:RNA-Binding Proteins; C010223:N-methyladenosine; D008780:Methyltransferases; C468275:METTL3 protein, human; D000241:Adenosine