Project description:Pseudouridine (Ψ) is an ubiquitous RNA modification, present in the tRNAs and rRNAs of species across all domains of life. Conserved pseudouridine synthases modify the mRNAs of diverse eukaryotes, but the modification has yet to be identified in bacterial mRNAs. Here, we report the discovery of pseudouridines in mRNA from E. coli. By testing the mRNA modification capacity of all 11 known pseudouridine synthases, we identify RluA as the predominant mRNA-modifying enzyme, modifying the majority of high-confidence sites.
Project description:Pseudouridine (Ψ) is an ubiquitous RNA modification, present in the tRNAs and rRNAs of species across all domains of life. Conserved pseudouridine synthases modify the mRNAs of diverse eukaryotes, but the modification has yet to be identified in bacterial mRNAs. Here, we report the discovery of pseudouridines in mRNA from E. coli. By testing the mRNA modification capacity of all 11 known pseudouridine synthases, we identify RluA as the predominant mRNA-modifying enzyme, modifying the majority of high-confidence sites.
Project description:Functional characterization of pseudouridine (Ψ) in mammalian messenger RNA (mRNA) has been hampered by the lack of a quantitative method that maps pseudouridine in the whole transcriptome. We report bisulfite-induced deletion sequencing (BID-seq) that utilizes a bisulfite-mediated reaction to stoichiometrically convert pseudouridine into deletion upon reverse transcription. BID-seq enabled detection of abundant pseudouridine sites with stoichiometry information in several human cell lines and 12 different mouse tissues using 10-20 ng input RNA. We uncovered consensus sequences for pseudouridine in mammalian mRNA and assigned different ‘writer’ proteins to individual pseudouridine deposition. Our results reveal a transcript stabilization role of Ψ sites installed by TRUB1 in human cancer cells. We also detected presence of Ψ within stop codons of mammalian mRNA, and confirmed the role of Ψ in promoting stop codon read-through in vivo. This new method for sensitive and comprehensive detection of Ψ sets the stage for future investigations of the roles of Ψ in diverse biological processes.
Project description:Pseudouridine is an isomer of uridine and is the most common RNA modification in both procaryotes and eucaryotes. It is found in ribosomal, transfer, and other structural RNA as well as in some mRNA and non-coding RNA. We have found abundant pseudouridine in small RNA and their precursors in Arabidopsis.
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.
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.
Project description:Pseudouridine is an isomer of uridine and is the most common RNA modification in both procaryotes and eucaryotes. It is found in ribosomal, transfer, and other structural RNA as well as in some mRNA and non-coding RNA. We have found abundant pseudouridine in small RNA and their precursors in Arabidopsis.
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 Ψ-seq, a method for transcriptome-wide quantitative mapping of pseudouridine. We validate Ψ-seq with synthetic spike-ins and de novo identification of the vast majority of previously reported pseudouridylated positions. Ψ-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 – 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.
Project description:Given the interest in the COVID mRNA vaccines, we sought to investigate how the RNA modification N1-methylpseudouridine (and its related modification, pseudouridine) is read by ribosomes and reverse transcriptases. By looking at reverse transcriptase data, we can gain information on how the modification affects duplex stability, which may have important consequences for the tRNA-mRNA interactions found in the ribosome.