MRNA juxtacap sequences govern mRNA translation and stability
Ontology highlight
ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE188510 | GEO | 2024/12/04
REPOSITORIES: GEO
Similar Datasets
Project description:mRNA juxtacap sequences govern mRNA translation and stability
| PRJNA779102 | ENA
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:Chemical modifications of RNAs have long been established as key modulators of nonprotein-coding RNA structure and function in cells. There is a growing appreciation that messenger RNA (mRNA) sequences responsible for directing protein synthesis can also be posttranscriptionally modified. The enzymatic incorporation of mRNA modifications has many potential outcomes, including changing mRNA stability, protein recruitment, and translation. We tested how one of the most common modifications present in mRNA coding regions, pseudouridine (Ψ), impacts protein synthesis using a fully reconstituted bacterial translation system and human cells. Our work reveals that replacing a single uridine nucleotide with Ψ in an mRNA codon impedes amino acid addition and EF-Tu GTPase activation. A crystal structure of the Thermus thermophilus 70S ribosome with a tRNAPhe bound to a ΨUU codon in the A site supports these findings. We also find that the presence of Ψ can promote the low-level synthesis of multiple peptide products from a single mRNA sequence in the reconstituted translation system as well as human cells, and increases the rate of near-cognate Val-tRNAVal reacting on a ΨUU codon. The vast majority of Ψ moieties in mRNAs are found in coding regions, and our study suggests that one consequence of the ribosome encountering Ψ can be to modestly alter both translation speed and mRNA decoding.
| S-EPMC6859337 | biostudies-literature
Project description:Mammalian poly A-binding proteins (PABPs) are highly conserved multifunctional RNA-binding proteins primarily involved in the regulation of mRNA translation and stability, of which PABPC1 is considered a central regulator of cytoplasmic mRNA homing and is involved in a wide range of physiological and pathological processes by regulating almost every aspect of RNA metabolism. Alterations in its expression and function disrupt intra-tissue homeostasis and contribute to the development of various tumors. There is increasing evidence that PABPC1 is aberrantly expressed in a variety of tumor tissues and cancers such as lung, gastric, breast, liver, and esophageal cancers, and PABPC1 might be used as a potential biomarker for tumor diagnosis, treatment, and clinical application in the future. In this paper, we review the abnormal expression, functional role, and molecular mechanism of PABPC1 in tumorigenesis and provide directions for further understanding the regulatory role of PABPC1 in tumor cells.
| S-EPMC9753129 | biostudies-literature
Project description:A set of 41 synthetic 5'UTRs with different theoretical translation initiation rates were generated to explore the role of 5'UTRs in the regulation of protein levels in Escherichia coli. The roles of the synthetic 5'UTRs in regulating the expression of different reporter genes were analyzed in vivo. Protein levels varied substantially between the different constructs but for most of the 5'UTRs, protein levels were not correlated with theoretical translation initiation rates. Large variations in mRNA concentrations were measured with the different 5'UTRs even though the same concentration of transcription inducer was used in each case. 5'UTRs were also found to strongly affect mRNA stability, and these changes in mRNA stability often contributed to observed differences in mRNA concentration. Unexpectedly, the effect of the 5'UTRs on mRNA half-lives was found to vary depending on the downstream reporter gene. These results clearly demonstrate that 5'UTRs contribute to gene expression regulation at the level of translation initiation and of mRNA stability, to an extent that depends on the nature of the downstream gene.
| S-EPMC9810816 | biostudies-literature
Project description:N6-methyladenosine (m6A) is the most abundant modified base in eukaryotic mRNA and has been linked to diverse effects on mRNA fate and function. Current m6A mapping approaches rely on immunoprecipitation of m6A-containing RNA fragments to identify regions of transcripts that contain m6A. This approach localizes m6A residues to 100-200 nt-long regions of transcripts. The precise position of m6A in mRNAs cannot be identified on a transcriptome-wide level because there are no chemical methods to distinguish between m6A and adenosine. Here we show that anti-m6A antibodies can induce specific mutational signatures at m6A residues after ultraviolet light-induced antibody-RNA crosslinking and reverse transcription. Similarly, we find these antibodies induce mutational signatures at N6, 2’-O-dimethyladenosine (m6Am), a nucleotide found at the first encoded position of certain mRNAs. Using these mutational signatures, we map m6A and m6Am at single-nucleotide resolution in human and mouse mRNA and identify snoRNAs as a novel class of m6A-containing ncRNAs. UV-crosslinking and immunoprecipitation with m6A-specific antibodies was used to map m6A and m6Am in cellular RNA with single nucleotide resolution.
2015-06-29 | E-GEOD-63753 | biostudies-arrayexpress
Project description:N6-methyladenosine (m6A), a major modification of messenger RNAs (mRNAs), plays critical roles in RNA metabolism and function. In addition to the internal m6A, N6, 2'-O-dimethyladenosine (m6Am) is present at the transcription start nucleotide of capped mRNAs in vertebrates. However, its biogenesis and functional role remain elusive. Using a reverse genetics approach, we identified PCIF1, a factor that interacts with the serine-5-phosphorylated carboxyl-terminal domain of RNA polymerase II, as a cap-specific adenosine methyltransferase (CAPAM) responsible for N6-methylation of m6Am. The crystal structure of CAPAM in complex with substrates revealed the molecular basis of cap-specific m6A formation. A transcriptome-wide analysis revealed that N6-methylation of m6Am promotes the translation of capped mRNAs. Thus, a cap-specific m6A writer promotes translation of mRNAs starting from m6Am.
2018-11-02 | GSE122071 | GEO
Project description:In this study we performed MeRIP-Seq to study N6-methyl adenosine (m6A) and and N6,2′ -O-dimethyladenosine (m6Am) modification of mRNA. We investigated the effect of the microbiota on the transcriptome and epitranscriptomic modifications in murine liver and cecum. We compared m6A/m modification profiles in cecum of conventionally raised (CONV) and germ-free (GF) mice. We additionally included GF mice colonised with the flora of CONV mice for four weeks (ex-GF), for which show that they exhibit similar patterns of the most abundant genera of gut bacteria as CONV mice. We added mice treated with several antibiotics to deplete the gut flora (abx)and vancomycin treated mice in which the genera Akkermansia, Escherichia/Shigella and Lactobacillus were enriched. Furthermore, we included GF mice colonised with the commensal bacterium Akkermansia muciniphila (Am), Lactobacillus plantarum (Lp) and Escherichia coli Nissle (Ec) and analysed their m6A/m modification profiles. In addition, we analysed changes in m6A/m- modified liver RNA for CONV, GF, and Am, Lp and Ec mice.
2020-02-12 | E-MTAB-6560 | biostudies-arrayexpress
Project description:T cell-based cancer immunotherapies have revolutionized cancer treatment, yet durable responses remain elusive. Here, we report that PCIF1, an RNA N6, 2’-O-dimethyladenosine (m6Am) methyltransferase, negatively regulates CD8+ T cell anti-tumor responses. Whole-body or T cell-specific Pcif1 knockout (KO) significantly reduces tumor growth in mice. Single-cell RNA sequencing reveals heightened tumor-infiltrating cytotoxic CD8+ T cells in Pcif1-deficient mice. Mechanistically, proteomic and m6Am-sequencing analyses pinpoint that Pcif1 KO elevates crucial m6Am-modified targets, specifically ferroptosis suppressor genes (Fth1, Slc3a2), and T cell activation gene Cd69, imparting resistance to ferroptosis and enhancing CD8+ T cell activation. Of note, Pcif1-deficient mice with tumors exhibit enhanced responses to anti-PD-1 immunotherapy, and Pcif1 KO CAR T cells demonstrate improved tumor control. Clinically, cancer patients with low PCIF1 expression in T cells exhibit enhanced responses to immunotherapies. These findings suggest that PCIF1 suppresses CD8+ T cell activation and targeting PCIF1 as a promising strategy to boost anti-tumor immunity.
2024-11-14 | GSE254597 | GEO
Project description:Post-transcriptional mRNA regulation shapes gene expression, yet how cis-elements and mRNA translation interface to regulate mRNA stability is poorly understood. We find that the strength of translation initiation, upstream open reading frame (uORF) content, codon optimality, AU-rich elements, microRNA binding sites, and open reading frame (ORF) length function combinatorially to regulate mRNA stability. Machine-learning analysis identifies ORF length as the most important conserved feature regulating mRNA decay. We find that Upf1 binds poorly translated and untranslated ORFs, which are associated with a higher decay rate, including mRNAs with uORFs and those with exposed ORFs after stop codons. Our study emphasizes Upf1's converging role in surveilling mRNAs with exposed ORFs that are poorly translated, such as mRNAs with long ORFs, ORF-like 3' UTRs, and mRNAs containing uORFs. We propose that Upf1 regulation of poorly/untranslated ORFs provides a unifying mechanism of surveillance in regulating mRNA stability and homeostasis in an exon-junction complex (EJC)-independent nonsense-mediated decay (NMD) pathway that we term ORF-mediated decay (OMD).
| S-EPMC11259039 | biostudies-literature