N1-methylpseudouridine found within COVID-19 mRNA vaccines produces faithful protein products
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ABSTRACT:
ORGANISM(S): synthetic construct
PROVIDER: GSE186464 | GEO | 2021/10/25
REPOSITORIES: GEO
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Project description:The COVID mRNA vaccines utilize the modified nucleobase N1-methylpseudouridine, in place of canonical uridine, to improve immunogenicity and protein yield. However, relatively few studies have investigated the effect of modified nucleobases on the fidelity of protein translation. Given the interest in the COVID mRNA vaccines, we sought to investigate how N1-methylpseudouridine (and the related modification pseudouridine) is read by ribosomes.
2022-08-18 | PXD029291 | Pride
Project description:Synthetic mRNA technology is a promising avenue for treating and preventing disease. Key to the technology is the incorporation of modified nucleotides such as N1-methylpseudouridine (m1Ψ) to decrease immunogenicity of the RNA. However, relatively few studies have addressed the effects of modified nucleotides on the decoding process. Here, we investigate the effect of m1Ψ and the related modification pseudouridine (Ψ) on translation. In a reconstituted system, we find that m1Ψ does not significantly alter decoding accuracy. More importantly, we do not detect an increase in miscoded peptides when mRNA containing m1Ψ is translated in cell culture, compared with unmodified mRNA. We also find that m1Ψ does not stabilize mismatched RNA-duplex formation and only marginally promotes errors during reverse transcription. Overall, our results suggest that m1Ψ does not significantly impact translational fidelity, a welcome sign for future RNA therapeutics.
| S-EPMC9376333 | biostudies-literature
Project description:N1-methylpseudouridine found within COVID-19 mRNA vaccines produces faithful protein products
| PRJNA773947 | ENA
Project description:Chemical modifications on mRNA are increasingly recognized as a critical regulatory layer of the flow of genetic information, but quantitative tools to monitor RNA modifications in a whole-transcriptome and site-specific manner are lacking. Here we describe a versatile directed evolution platform that rapidly selects for reverse transcriptases that install mutations during reverse transcription at sites of a given type of RNA modification, allowing for site-specific identification of the modification. To develop and validate the platform, we evolved the HIV-1 reverse transcriptase against N1-methyladenosine (m1A). Iterative rounds of selection yielded reverse transcriptases with both robust read-through and high mutation rates at m1A sites. We apply the evolved reverse transcriptase to identify thousands of statistically confident m1A sites in human mRNA, some of which can be detected in antibody-free RNA-seq libraries. Together, this work develops and validates the reverse transcriptase evolution platform and provides new tools, analysis methods, and datasets to study m1A biology.
2019-09-24 | GSE123365 | GEO
Project description:Thermostable reverse transcriptases are workhorse enzymes underlying nearly all modern techniques for RNA structure mapping and for transcriptome-wide discovery of RNA chemical modifications. Despite their wide use, these enzymes’ behaviors at chemical modified nucleotides remain poorly understood. Wellington-Oguri et al. recently reported an apparent loss of chemical modification within putatively unstructured polyadenosine stretches modified by dimethyl sulfate or 2’ hydroxyl acylation, as probed by reverse transcription. Here, re-analysis of these and other publicly available data, capillary electrophoresis experiments on chemically modified RNAs, and nuclear magnetic resonance spectroscopy on A 12 and variants show that this effect is unlikely to arise from an unusual structure of polyadenosine. Instead, tests of different reverse transcriptases on chemically modified RNAs and molecules synthesized with single 1-methyladenosines implicate a previously uncharacterized reverse transcriptase behavior: near-quantitative bypass through chemical modifications within polyadenosine stretches. All tested natural and engineered reverse transcriptases (MMLV; SuperScript II, III, and IV; TGIRT-III; and MarathonRT) exhibit this anomalous bypass behavior. Accurate DMS-guided structure modeling of the polyadenylated HIV-1 3´ untranslated region RNA requires taking into account this anomaly. Our results suggest that poly(rA-dT) hybrid duplexes can trigger unexpectedly effective reverse transcriptase bypass and that chemical modifications in poly(A) mRNA tails may be generally undercounted.
2020-04-22 | GSE149061 | GEO
Project description:The abundant RNA modification pseudouridine (Ψ) has been mapped transcriptome-wide by chemically modifying pseudouridines with carbodiimide and detecting the resulting reverse transcription stops in high-throughput sequencing. However, these methods have limited sensitivity and specificity, in part due to the use of reverse transcription stops. We sought to use mutations rather than just stops in sequencing data to identify pseudouridine sites. Here, we identify reverse transcription conditions that allow read-through of carbodiimide-modified pseudouridine (CMC-Ψ), and we show that pseudouridines in carbodiimide-treated human ribosomal RNA have context-dependent mutation and stop rates in high-throughput sequencing libraries prepared under these conditions. Furthermore, accounting for the context-dependence of mutation and stop rates can enhance the detection of pseudouridine sites. Similar approaches could contribute to the sequencing-based detection of many RNA modifications.
2018-05-07 | GSE110247 | GEO
Project description:Chemical probing has the power to provide insight into RNA conformation in vivo and in vitro, but interpreting the results depends on methods to detect the chemically modified nucleotides. Traditionally, the presence of modified bases was inferred from their ability to halt reverse transcriptase during primer extension and the locations of termination sites observed by electrophoresis or sequencing. More recently, modification-induced mutations have been used as a readout for chemical probing data. Given variable propensity for mismatch incorporation and read-through with different reverse transcriptases, we examined how termination and mutation events compare to each other in the same chemical probing experiments. We found that mutations and terminations induced by dimethyl sulfate probing are both specific for methylated bases, but these two measures have surprisingly little correlation and represent largely non-overlapping indicators of chemical modification data. We also show that specific biases for modified bases depend partly on local sequence context, and that different reverse transcriptases show different biases toward reading a modification as a stop or a mutation. These results support approaches that incorporate analysis of both termination and mutation events into RNA probing experiments.
2017-09-26 | GSE97609 | GEO
Project description:23S ribosomal RNA (rRNA) of Escherichia coli 50S large ribosome subunit contains 26 post-transcriptionally modified nucleosides. Here, we determine the extent of modifications in the 35S and 45S large subunit intermediates, accumulating in cells expressing the helicase inactive DbpA protein, R331A, and the native 50S large subunit. The modifications we characterized are nine pseudouridines, 3-methylpseudouridine, 2-methyladenine, and 5-hydroxycytosine. These modifications were detected using 1-cyclohexyl-(2-morpholinoethyl)carbodiimide metho-p-toluene sulfonate (CMCT) treatment followed by alkaline treatment. In addition, KMnO4 treatment of 23S rRNA was employed to detect 5-hydroxycytosine modification. CMCT and KMnO4 treatment produce chemical changes in modified nucleotides that cause reverse transcriptase misincorporations and deletions, which were detected employing next generation sequencing. Our results show that seven uridines to pseudouridine isomerizations and the 2-methyladenosine modification are present both in the 35S and 45S to similar extents as in the 50S. Hence, the enzymes that perform these modifications, namely RluF, RluB, RlmN, RluA, RluC, and RluA, have already acted in the intermediates. While two uridines to pseudouridines isomerizations, the 3-methylpseudouridine, and 5-hydroxycytosine modifications are significantly less present in the 35S and 45S as compared to the 50S. Therefore, the enzymes that perform these modifications, RluD, RlmH, and RlhA, are in the process of modifying the 35S, and 45S or these enzymes act during the later stages of ribosome assembly. Our study employs a novel high throughput and single nucleotide resolution technique for detection of 2-methyladenine and two novel high throughput and single nucleotide resolution technique for detection of 5-hydroxycytosine.
2022-09-15 | GSE196821 | GEO
Project description:Pseudouridine is the most abundant modification occurring on RNA, yet with the exception of a few well-studied RNA molecules little is known about the modified positions and their function(s). Here, we develop M-NM-(-seq, a method for transcriptome-wide quantitative mapping of pseudouridine. We validate M-NM-(-seq with synthetic spike-ins and de novo identification of the vast majority of previously reported pseudouridylated positions. M-NM-(-seq permits discovery of hundreds of novel pseudouridine modifications in human and yeast mRNAs and snoRNAs. Knockdown and knockout of pseudouridine synthases uncovers the cognate PUSs mediating pseudouridine catalysis at these individual novel sites and their target sequence features. In both human and yeast pseudouridine formation on mRNA depends on both site-specific PUSs M-bM-^@M-^S often guided by a specific sequence motif - and snoRNA-guided PUSs. Importantly, upon heat shock in yeast, Pus7-mediated pseudouridylation is induced at >200 sites in diverse mRNAs. Pus7 deletion in yeast leads to decreased recovery from heat shock and decreased RNA levels at otherwise pseudouridylated messages, suggesting a role for pseudouridine in enhancing transcript stability. Pseudouridine stoichiometries in rRNA are highly conserved from yeast to mammals, but are reduced in cells derived from dyskeratosis congenita patients, where the pseudouridine synthase DKC1 is mutated, compared to age matched controls. Our results establish pseudouridine as a ubiquitous and dynamic modification in mRNA, and provide a sensitive, quantitative and transcriptome-wide methodology to address its underlying mechanisms and function. Examination of m6A methylation in human Hek293 and A549 cell lines, in human embryonic stem cells (ESCs) undergoing differentiation to neural progenitor cells (NPCs), in OKMS inducible fibroblasts reprogrammed into iPSC, and upon knockdown of factors using siRNAs or shRNAs.
2014-09-11 | E-GEOD-60047 | biostudies-arrayexpress