FTO controls reversible m6Am RNA methylation during snRNA biogenesis
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ABSTRACT:
PROVIDER: PRJNA421745 | ENA |
REPOSITORIES: ENA
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Project description:Small nuclear RNAs (snRNAs) are core spliceosome components and mediate pre-mRNA splicing. Here we show that snRNAs contain a regulated and reversible nucleotide modification causing them to exist as two different methyl isoforms, m 1 and m 2 , reflecting the methylation state of the adenosine adjacent to the snRNA cap. We find that snRNA biogenesis involves the formation of an initial m 1 isoform with a single-methylated adenosine (2′-O-methyladenosine, Am), which is then converted to a dimethylated m 2 isoform (N 6 ,2′-O-dimethyladenosine, m 6 Am). The relative m 1 and m 2 isoform levels are determined by the RNA demethylase FTO, which selectively demethylates the m 2 isoform. We show FTO is inhibited by the oncometabolite d-2-hydroxyglutarate, resulting in increased m 2 -snRNA levels. Furthermore, cells that exhibit high m 2 -snRNA levels show altered patterns of alternative splicing. Together, these data reveal that FTO controls a previously unknown central step of snRNA processing involving reversible methylation, and suggest that epitranscriptomic information in snRNA may influence mRNA splicing.
2019-02-18 | GSE107872 | GEO
Project description:Internal bases in mRNA can be subjected to modifications that influence the fate of mRNA in cells. One of the most prevalent modified bases is found at the 5′ end of mRNA, at the first encoded nucleotide adjacent to the 7-methylguanosine cap. Here we show that this nucleotide, N6,2′-O-dimethyladenosine (m6Am), is a reversible modification that influences cellular mRNA fate. Using a transcriptome-wide map of m6Am we find that m6Am-initiated transcripts are markedly more stable than mRNAs that begin with other nucleotides. We show that the enhanced stability of m6Am-initiated transcripts is due to resistance to the mRNA-decapping enzyme DCP2. Moreover, we find that m6Am is selectively demethylated by fat mass and obesity-associated protein (FTO). FTO preferentially demethylates m6Am rather than N6-methyladenosine (m6A), and reduces the stability of m6Am mRNAs. Together, these findings show that the methylation status of m6Am in the 5′ cap is a dynamic and reversible epitranscriptomic modification that determines mRNA stability.
2016-12-21 | GSE78040 | GEO
Project description:Cancer stem cells (CSCs) are a small but critical cell population for cancer biology since they display inherent resistance to standard therapies and give rise to metastases. Despite accruing evidence establishing a link between deregulation of epitranscriptome-related players and tumorigenic process, the role of messenger RNA (mRNA) modifications dynamic in the regulation of CSC properties remains poorly understood. Here, we show that the cytoplasmic pool of fat mass and obesity-associated protein (FTO) impedes CSC abilities in colorectal cancer through its m6Am (N6,2'-O-dimethyladenosine) demethylase activity. While m6Am is strategically located next to the m7G-mRNA cap, its biological function is not well understood and has not been addressed in cancer. Low FTO expression in patient-derived cell lines elevates m6Am level in mRNA which results in enhanced in vivo tumorigenicity and chemoresistance. Inhibition of the nuclear m6Am methyltransferase, PCIF1/CAPAM, fully reverses this phenotype, stressing the role of m6Am modification in stem-like properties acquisition. FTO-mediated regulation of m6Am marking constitutes a novel, reversible pathway controlling CSC abilities. Altogether, our findings bring to light the first biological function of the m6Am modification and its potential adverse consequences for colorectal cancer management.
2021-01-20 | GSE165115 | GEO
Project description:N6-methylation of 2’-O-methyladenosine (Am) in RNA occurs in eukaryotic cells to generate N6,2’-O-dimethyladenosine (m6Am). Identification of the methyltransferase responsible for m6Am catalysis has accelerated studies on the function of m6Am in RNA processing. While m6Am is generally found in the first transcribed nucleotide of mRNAs, the modification is also found internally within U2 snRNA. However, the writer required for catalyzing internal m6Am formation had remained elusive. By sequencing transcriptome-wide RNA methylation at single-base-resolution, we identified human METTL4 as the writer that directly methylates Am at U2 snRNA position 30 into m6Am. We found that METTL4 localizes to the nucleus and its conserved methyltransferase catalytic site is required for U2 snRNA methylation. By sequencing human cells with overexpressed Mettl4, we determined METTL4’s in vivo target RNA motif specificity. In the absence of Mettl4 in human cells, U2 snRNA lacks m6Am thereby affecting a subset of splicing events that exhibit specific features such as overall 3’ splice-site weakness with certain motif positions more affected than others. This study establishes that METTL4 methylation of U2 snRNA regulates splicing of specific pre-mRNA transcripts.
2020-08-17 | GSE144745 | GEO
Project description:FTO, the first RNA demethylase discovered, mediates the demethylation of N6-methyladenosine (m6A), installed internally on messenger RNA, and N6,2′-O-dimethyladenosine (m6Am), occurring at the +1 position from the 5’ cap. Despite extensive recent research on FTO, its physiological impact on cellular processes has yet to be fully elucidated. Here, we demonstrate that the cellular distribution of FTO is distinct among different cell lines, which critically affects the access of FTO to different RNA substrates. FTO binds multiple RNA substrates, including mRNA, U6 RNA, and tRNA. It mainly targets internal m6A when located in the cell nucleus and preferentially demethylates m6Am when residing in the cytoplasm. The expression levels of transcripts containing internal m6A are associated with the alteration of the FTO more so than transcripts containing m6Am. We also discover that N1-methyladenosine (m1A) in tRNA is a main substrate of FTO, with the FTO-catalyzed demethylation of target tRNAs repressing protein synthesis. Collectively, FTO-mediated RNA demethylation affects both mRNA level and translation through distinct pathways.
2018-09-14 | GSE106395 | GEO
Project description:Proteomics of HEPG2 cells following FTO overexpression and knockdown. Data accompany our paper entitled “Dynamic Regulation of N6,2′-O-dimethyladenosine (m6Am) in Obesity” scheduled for publication in Nature Communications, 2021
2021-10-27 | PXD029268 | Pride
Project description: Not available
| S-EPMC6984009 | biostudies-literature
Project description:N6-Methyladenosine (m6A) and N6,2′-O-dimethyladenosine (m6Am) are abundant mRNA modifications that regulate transcript processing and translation. The role of both, here termed m6A/m, in the stress response in the adult brain in vivo are currently unknown. Here, we investigated the effect of gene deletion of Mettl3, a m6A methyltransferase, and Fto, a m6A and m6Am demethlyase, induced in adulthood in excitatory neurons of the neocortex and hippocampus (Camk2a-Cre Mettl3 or Fto cKO) on the cortical epitranscriptome. PolyA-RNA-fragments from 3-5 replicates per group were processed both as m6A/m-sample (RNA immunoprecipiation RIP with an m6A and m6Am antibody) and RNA-input sample.
2018-07-10 | GSE113793 | GEO
Project description:Reversible methylation of m6Am in the 5′ cap controls mRNA stability
| PRJNA312400 | ENA
Project description:N6-Methyladenosine (m6A) and N6,2′-O-dimethyladenosine (m6Am) are abundant mRNA modifications that regulate transcript processing and translation. The role of both, here termed m6A/m, in the stress response in the adult brain in vivo are currently unknown. Here, we investigated the effect of gene deletion of Mettl3, a m6A methyltransferase, and Fto, a m6A and m6Am demethlyase, induced in adulthood in excitatory neurons of the CA1 and CA3 in the hippocampus (Nex-CreERT2 Mettl3 or Fto cKO) on the transcriptome of CA1 and CA3 as well as the transcriptomic response of the CA1 and CA3 transcriptome to fear conditioning.
2018-07-10 | GSE113796 | GEO