N6-Adenosine methylation regulates the translation of insulin mRNA
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ABSTRACT:
PROVIDER: PRJNA856133 | ENA |
REPOSITORIES: ENA
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Project description:Relatively little is known about the first step of insulin synthesis: the translation of the mRNA. Here we show that the translation of D. melanogaster insulin 2 mRNA (dilp2) is controlled by methylation of N6-adenosine (m6A) in the 3’ UTR. Mutations in the m6A writer Mettl3 and methylated residues in the dilp2 3’UTR decreased the levels of dilp2 mRNA associated with the polysomes and the total amount of dilp2 protein produced. This resulted in aberrant energy homeostasis and diabetic-like phenotypes consistent with the specific function of dilp2 in adult metabolism. Conserved m6A signatures were also identified in the 3’ UTRs of vertebrate insulin mRNAs. These data identify m6A as a key regulator of insulin protein synthesis and energy homeostasis in metazoans with important implications for diabetes and metabolic disease.
2023-04-25 | GSE207547 | GEO
Project description:N6-methyladenosine (m6A) is the most prevalent internal modification found in mammalian messenger and non-coding RNAs. The discoveries of functionally significant demethylases that reverse this methylation as well as the recently revealed m6A distributions in mammalian transcriptomes strongly indicate regulatory functions of this modification. Here we report the identification and characterization of the mammalian nuclear RNA N6-adenosine methyltransferase core (RNMTC) complex. Besides METTL3, a methyltransferase which was the only known component of RNMTC in the past, we discovered that a previously uncharacterized methyltransferase, METTL14, exhibits a N6-adenosine methyltransferase activity higher than METTL3. Together with WTAP, the third component that dramatically affects the cellular m6A level, these three proteins form the core complex that orchestrates m6A deposition on mammalian nuclear RNA. Biochemistry assays, imaging experiments, as well as transcriptome-wide analyses of the binding sites and their effects on m6A methylation support methylation function and reveal new insights of RNMTC. PAR-CLIP and m6A-seq in HeLa cells
2013-11-29 | E-GEOD-46705 | biostudies-arrayexpress
Project description:• Among many mRNA modifications, adenine methylation at the N6 position (N6-methyladenosine, m6A) is known to affect mRNA biology extensively. The influence of m6A has yet to be assessed under drought, one of the most impactful abiotic stresses. • We show that Arabidopsis thaliana (L.) Heynh. (Arabidopsis) plants lacking mRNA ADENOSINE METHYLASE (MTA) are drought sensitive. Subsequently, we comprehensively assess the impacts of MTA-dependent m6A changes during drought on mRNA abundance, stability, and translation in Arabidopsis. • During drought, there is a global trend towards hyper-methylation of many protein-coding transcripts that does not occur in mta. We also observe complex regulation of m6A at a transcript-specific level, possibly reflecting compensation by other m6A components. Importantly, a subset of transcripts that are hyper-methylated in an MTA-dependent manner exhibited reduced turnover and translation in mta, compared to wild-type plants, during drought. Additionally, MTA impacts transcript stability and translation independently of m6A. We also correlate drought-associated deposition of m6A with increased translation of modulators of drought response, such as RD29A, COR47, COR413, ALDH2B, ERD7, and ABF4 in WT, which is impaired in mta. • m6A is dynamic during drought and, alongside MTA, promotes tolerance by regulating drought-responsive changes in transcript turnover and translation.
2024-10-07 | GSE243365 | GEO
Project description:Methylation of N6-adenosine (me6A) has been observed in rRNA, tRNA, snoRNA, lncRNA and mRNA (ref.), but not yet miRNA. Interestingly, many mRNAs contain miRNA-binding sites and me6A in their 3'-UTR, although they do not appear to overlap (Mayer). We have investigated whether adenosine methylation affects miRNA levels and whether miRNAs are methylated. Indeed, we have obtained evidence suggesting that miRNA can be methylated and that the steady state level of certain miRNAs is affected by the level of the 6meA demethylase FTO.
2015-07-20 | GSE59767 | GEO
Project description:N6-methyladenosine (m6A) is the most abundant internal messenger (mRNA) modification in mammalian mRNA. This modification is reversible and non-stoichiometric, which potentially adds an additional layer of variety and dynamic control of mRNA metabolism. The m6A-modified mRNA can be selectively recognized by the YTH family “reader” proteins. The preferential binding of m6A-containing mRNA by YTHDF2 is known to reduce the stability of the target transcripts; however, the exact effects of m6A on translation has yet to be elucidated. Here we show that another m6A reader protein, YTHDF1, promotes ribosome loading of its target transcripts. YTHDF1 forms a complex with translation initiation factors to elevate the translation efficiency of its bound mRNA. In a unified mechanism of translation control through m6A, the YTHDF2-mediated decay controls the lifetime of target transcripts; whereas, the YTHDF1-based translation promotion increases the translation efficiency to ensure effective protein production from relatively short-lived transcripts that are marked by m6A. PAR-CLIP and RIP was used to identify YTHDF1 binding sites followed by ribosome profling and RNA seq to assess the consequences of YTHDF1 siRNA knock-down
2015-06-09 | E-GEOD-63591 | biostudies-arrayexpress
Project description:N6-methyladenosine (m6A) is the most prevalent internal modification found in mammalian messenger and non-coding RNAs. The discoveries of functionally significant demethylases that reverse this methylation as well as the recently revealed m6A distributions in mammalian transcriptomes strongly indicate regulatory functions of this modification. Here we report the identification and characterization of the mammalian nuclear RNA N6-adenosine methyltransferase core (RNMTC) complex. Besides METTL3, a methyltransferase which was the only known component of RNMTC in the past, we discovered that a previously uncharacterized methyltransferase, METTL14, exhibits a N6-adenosine methyltransferase activity higher than METTL3. Together with WTAP, the third component that dramatically affects the cellular m6A level, these three proteins form the core complex that orchestrates m6A deposition on mammalian nuclear RNA. Biochemistry assays, imaging experiments, as well as transcriptome-wide analyses of the binding sites and their effects on m6A methylation support methylation function and reveal new insights of RNMTC.
2013-11-29 | GSE46705 | GEO
Project description:Transcription and translation are two main pillars of gene expression. Due to the different timings, spots of action, and mechanisms of regulation, these processes are mainly regarded as distinct and generally uncoupled, despite serving a common purpose. Here, we sought for a possible connection between transcription and translation. Employing an unbiased screen of multiple human promoters, we identified a positive effect of TATA box on translation and a general coupling between mRNA expression and translational efficiency. Using a CRISPR-Cas9-mediated approach, genome-wide analyses, and in vitro experiments, we show that the rate of transcription regulates the efficiency of translation. Furthermore, we demonstrate that m6A modification of mRNAs is co-transcriptional and depends upon the dynamics of the transcribing RNAPII. Suboptimal transcription rates lead to elevated m6A content, which may result in reduced translation. This study uncovers a general and widespread link between transcription and translation that is governed by epigenetic modification of mRNAs.
| S-EPMC5388891 | biostudies-literature
Project description:The integrated stress response (ISR) facilitates cellular adaptation to a variety of stress conditions via phosphorylation of the common target eIF2α. During ISR, the translation of certain stress-related mRNAs is upregulated in spite of global suppression of protein synthesis.The selective translation often relieson alternative mechanisms, such as leaky scanning or reinitiation, but the underlying mechanism remains incompletely understood. Here we report that,in response to amino acid starvation, the reinitiation of ATF4 is not only governed by eIF2α-controlled ternary complex availability, but is also subjected to regulation by mRNA methylation in the form of N6-methyladenosine (m6A). We demonstrate that m6A in the 5' untranslated region (5’ UTR) controls ribosome scanning and subsequent start codonselection. Global profiling of initiating ribosomes reveals widespread alternative translation events influenced by mRNA methylation. Consistently, Fto-transgenic mice manifest enhanced ATF4 expression, highlighting the critical role of 5’ UTR methylation in translational regulation of ISR at cellular and organismal levels.
2017-08-15 | GSE102659 | GEO
Project description:N6-methyladenosine (m6A) modification is the most abundant internal RNA modification in eukaryotes. Recent studies have shown that the dynamic and reversible regulation of m6A modifications in mRNAs or non-coding RNAs plays critical roles in tissue development, stem cell self-renewal and differentiation, control of heat shock response, and circadian clock controlling, as well as in RNA metabolism and processing. METTL14 is a major m6A writer which together with METTL3 forms the core of the methyltransferase complex that catalyzes the conversion of adenosine (A) to m6A. To investigate the effect of METTL14 on m6A modfication, we performed m6A-seq in HepG2 cells with stably expressed shRNAs against METTL14 (shMETTL14) or non-specific control shRNA (shNS).
2018-03-26 | GSE90642 | GEO
Project description:Pancreatic beta-cells are specialized for coupling glucose metabolism to insulin peptide production and secretion. Acute glucose exposure robustly and coordinately increases translation of proinsulin and proteins required for secretion of mature insulin peptide. By contrast, chronically elevated glucose levels that occur during diabetes impair beta-cell insulin secretion and have been shown experimentally to suppress insulin translation. Whether translation of other genes critical for insulin secretion are similarly downregulated by chronic high glucose is unknown. Here, we used high-throughput ribosome profiling and nascent proteomics in MIN6 insulinoma cells to elucidate the genome-wide impact of sustained high glucose on beta-cell mRNA translation. Prior to induction of ER stress or suppression of global translation, sustained high glucose suppressed glucose-stimulated insulin secretion and downregulated translation of not only insulin, but also of mRNAs related to insulin secretory granule formation, exocytosis, and metabolism-coupled insulin secretion. Translation of these mRNAs was also downregulated in primary rat and human islets following ex-vivo incubation with sustained high glucose and in an in vivo model of chronic mild hyperglycemia. Furthermore, translational downregulation decreased cellular abundance of these proteins. Our study uncovered a translational regulatory circuit during beta-cell glucose toxicity that impairs expression of proteins with critical roles in beta-cell function.
2023-12-01 | GSE248349 | GEO