Project description:Pseudouridine is considered as the most abundant modified nucleotides in RNA, playing an indispensable role in various life processes. The identification of pseudouridine sites provides the basis for the study of their function. Here, we proposed a new method for the identification of pseudouridine sites with a higher signal-to-noise ratio, combining CMC-specific labeling of pseudouridine sites and exonuclease-assisted strategy. We called this method exonuclease-assisted identification of pseudouridine sites (EAIPS).
Project description:We applied BIHIND-seq to 15 sites of Hela 18S rRNA to probe Pseudouridine modification at the target sites and checked how pseudouridine level changed after DKC1 knockdown.
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 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:Antisense long non-coding (aslnc)RNAs represent a substantial part of eukaryotic transcriptomes that are, in yeast, controlled by the Xrn1 exonuclease. Nonsense-Mediated Decay (NMD) destabilizes the Xrn1-sensitive aslncRNAs (XUT), but what determines their sensitivity remains unclear. We report that 3’ single-stranded (3’-ss) extension mediates XUTs degradation by NMD, assisted by the Mtr4 and Dbp2 helicases. Single-gene investigation, genome-wide RNA analyses and double-stranded (ds)RNA mapping revealed that 3'-ss extensions discriminate the NMD-targeted XUTs from stable lncRNAs. Ribosome profiling showed that XUT are translated locking them for NMD activity. Interestingly, mutants of the Mtr4 and Dbp2 helicases accumulated XUTs, suggesting that dsRNA unwinding is a critical step for degradation. Indeed, expression of anti-complementary transcripts protects cryptic intergenic lncRNAs from NMD. Our results indicate that aslncRNAs form dsRNA that are only translated and targeted to NMD if dissociated by Mtr4 and Dbp2. We propose that NMD buffers genome expression by discarding pervasive regulatory transcripts.
Project description:Pseudouridine (Ψ) is one of the most abundant modifications in cellular RNA. However, its function remains elusive, mainly due to the lack of highly sensitive and accurate detection methods. To address this challenge, we introduced 2-bromoacrylamide-assisted cyclization sequencing (BACS) for quantitative profiling of Ψ at single-base resolution. Based on novel bromoacrylamide cyclization chemistry, BACS enables a Ψ-to-C transition. Compared to previous methods, BACS allowed the precise identification of Ψ positions, especially in densely modified Ψ regions and consecutive uridine sequences. BACS successfully detected all known Ψ sites in human rRNA and spliceosomal snRNAs and generated the first quantitative Ψ map of human snoRNA and tRNA. Furthermore, BACS simultaneously detected adenosine-to-inosine (A-to-I) editing sites and N1-methyladenosine (m1A). Depletion of three key pseudouridine synthases (PUS) enabled us to elucidate the targets and sequence motifs of TRUB1, PUS7, and PUS1 in HeLa cells. We further applied BACS to Epstein-Barr virus (EBV)-encoded small RNAs (EBERs) and identified a highly abundant Ψ114 site in EBER2. Surprisingly, applying BACS to a panel of RNA viruses demonstrated the absence of Ψ in their viral transcripts or genomes, shedding light on differences in pseudouridylation between virus families. We anticipate BACS to serve as a powerful tool to uncover the biological importance of Ψ in future studies.
Project description:Pseudouridine (ψ) is the most common non-canonical ribonucleoside present on mammalian non-coding RNAs (ncRNAs), where is contributes ~10% of the total uridine level. However, ψ constitutes only ~0.3% of the uridines present on mRNAs and its effect on mRNA function remains unclear. Ψ residues have however been shown to inhibit the detection of exogenous RNA transcripts by host innate immune factors, thus raising the possibility that viruses might have subverted the addition of ψ residues to mRNAs by host pseudouridine synthase (PUS) enzymes as a way to inhibit antiviral responses in infected cells. Here, we describe and validate a novel antibody-based ψ mapping technique called photo-crosslinking assisted ψ sequencing (PA-ψ-seq) and then use it to map ψ residues on not only multiple cellular RNAs but also the mRNAs and genomic RNA encoded by HIV-1. We also describe several 293T-derived cell lines in which human PUS enzymes previously reported to add ψ residues to mRNAs, specifically PUS1, PUS7 and TRUB1/PUS4, were individually inactivated by gene editing. Surprisingly, while this allowed us to assign several sites of ψ addition on cellular mRNAs to each of these three PUS enzymes, the ψ sites present on HIV-1 transcripts remained unaffected. However, loss of PUS1 function did significantly reduce HIV-1 gene expression by a presumably indirect mechanism.
Project description:In an effort to produce a mouse model of Mitochondrial Myopathy with Lactic acidosis and Sideroblastic Anemia (MLASA), we knocked out the gene for Pseudouridine synthase 1 (PUS1), an enzyme that modifies uridine to pseudouridine in many cytoplasmic and mitochondrial tRNAs, as well as other cellular RNAs. The Pus1-/- mice are viable, are born at the expected Mendelian frequency, and are non-dysmorphic. The PUS1 mRNA and certain pseudouridine modifications are absent in cytoplasmic and mitochondrial tRNAs in the Pus1-/- mice. The Pus1-/- mice display reduce exercise capacity at 14 weeks, with alterations in muscle morphology, histology, and physiology. Red gastrocnemius muscle from Pus1-/- mice shows reduced number and size of mitochondria and reduced Cytochrome C oxidase activity. Two-condition, two-color experiment: Mouse wild type PUS1 and homozygous mutant PUS1 kidney tissue samples: 4 biological replicates each.