Project description:Pseudouridine (Ψ) is the most abundant RNA modification, yet little is known about its content, dynamics and function in mRNA and ncRNA. Here, we perform quantitative MS analysis and develop CAP-seq for transcriptome-wide Ψ profiling. The unexpected high Ψ content (Ψ/U ratio: ~ 0.2% to 0.6%) indicates that pseudouridylation in mammalian mRNA is much more prevalent and comprehensive than previously believed. In concordance, CAP-seq identified 2,084 Ψ sites within 1,929 human transcripts. We prove four previously unknown Ψ sites in rRNA and EEF1A1 mRNA. Genetic and biochemical analysis uncover PUS1 as a major human mRNA Ψ synthase. In response to stimuli, Ψ level and sites are dynamically modulated in stimulus-specific manners. Comparisons between human and mouse pseudouridylation reveal conserved and unique sites across tissue and species. We observe stop codon pseudouridylation and readthrough events simultaneously for HSPB1 mRNA, indicating a role in nonsense suppression. Together, these approaches allow in-depth analysis of transcriptome-wide pseudouridylation events and our comprehensive study provides a resource for functional studies of Ψ-mediated epigenetic regulation. Here we report a transcriptome-wide profiling method that utilizes a chemically synthesized N3-CMC, which pre-enriches the Ψ-containing RNAs and blocks the reverse transcription.Mapping the Ψ sites in human transcriptome was performed using HEK293T and PUS1 dependent Ψ sites were identified by comparing PUS1 knock out cells with wildtype cells. Stress inducible or suppressed Ψ sites were identified by comparing stress treated cells with untreated cells. And mouse brain and liver were used to map Ψ sites in mouse transcriptome.
Project description:Pseudouridine (Ψ) is the most abundant RNA modification, yet little is known about its content, dynamics and function in mRNA and ncRNA. Here, we perform quantitative MS analysis and develop CAP-seq for transcriptome-wide Ψ profiling. The unexpected high Ψ content (Ψ/U ratio: ~ 0.2% to 0.6%) indicates that pseudouridylation in mammalian mRNA is much more prevalent and comprehensive than previously believed. In concordance, CAP-seq identified 2,084 Ψ sites within 1,929 human transcripts. We prove four previously unknown Ψ sites in rRNA and EEF1A1 mRNA. Genetic and biochemical analysis uncover PUS1 as a major human mRNA Ψ synthase. In response to stimuli, Ψ level and sites are dynamically modulated in stimulus-specific manners. Comparisons between human and mouse pseudouridylation reveal conserved and unique sites across tissue and species. We observe stop codon pseudouridylation and readthrough events simultaneously for HSPB1 mRNA, indicating a role in nonsense suppression. Together, these approaches allow in-depth analysis of transcriptome-wide pseudouridylation events and our comprehensive study provides a resource for functional studies of Ψ-mediated epigenetic regulation.
Project description:In cells lacking the histone methyltransferase Set2, initiation of RNA polymerase II transcription occurs inappropriately within the protein-coding regions of genes, rather than being restricted to the proximal promoter. Here, we mapped the transcripts produced in an S. cerevisiae strain lacking Set2, and applied rigorous statistical methods to identify sites of cryptic transcription at high resolution.
Project description:Genome wide mapping of RNA polymearase III binding sites in Saccharomyces cerevisiae under normal growth and nutrient starved condition using ChIP-seq. Chromatin Immuno-precipitation (ChIP) was performed for FLAG tagged version of pol III subunit RPC128 after crosslinking the log-phase cells with formaldehyde. MOCK and IP DNA was sequenced and coverage of pol III was calculated at each base of the genome.
Project description:The majority of Saccharomyces cerevisiae snoRNA promoters contain an aRCCCTaa sequence motif located at the upstream border of a TATA-containing nucleosome-free region. Genome-wide ChIP-seq analysis showed that these motifs are bound in vivo by Tbf1, a telomere-binding protein known to recognize mammalian-like T2AG3 repeats at sub-telomeric regions. Tbf1 has over 100 additional promoter targets, including the TBF1 gene itself. Tbf1 is required for full snoRNA expression, yet it does not influence nucleosome positioning at snoRNA promoters. Analysis of Tbf1-binding sites in Saccharomyces cerevisiae by ChIP-seq of a Myc-tagged strain and a control untagged strain. 1 sample per strain, 1 lane per sample.
Project description:Genome wide mapping of RNA polymearase III binding sites in Saccharomyces cerevisiae under normal growth and nutrient starved condition using ChIP-seq. Chromatin Immuno-precipitation (ChIP) was performed for FLAG tagged version of pol III subunit RPC128 after crosslinking the log-phase cells with formaldehyde. MOCK and IP DNA was sequenced and coverage of pol III was calculated at each base of the genome. RPC128-FLAG ChIP-seq single end seqquencing on Illumina GAII. 2 replicates of IP samples and 1 MOCK sample. Done in under normal growth and nutrient deprivation (4 hours).
Project description:Pseudouridine (Ψ) is an abundant post-transcriptional RNA modification in ncRNA and mRNA. However, transcriptome-wide measurement of individual Ψ sites remains unaddressed. Here, we develop “PRAISE”, via selective chemical labeling of Ψ by bisulfite to induce nucleotide deletion signature during reverse transcription, to realize quantitative assessment of the Ψ landscape in the human transcriptome. Unlike traditional RNA/DNA bisulfite treatment, our approach is based on quaternary base mapping and identifies 2,209 confident Ψ sites in HEK293T cells. By perturbing pseudouridine synthases, we obtained differential mRNA targets of PUS1, PUS7, TRUB1 and DKC1. In addition, we identified known and novel Ψ sites in mitochondrial mRNA, which are catalyzed by a mitochondria-localized isoform of PUS1. Collectively, we provide a reliable, sensitive and convenient method to quantify transcriptome-wide Ψ; we envision this approach would facilitate emerging efforts to elucidate the function and mechanism of mRNA pseudouridylation.
Project description:MNase-seq Experiments from Calorie Restricted and Non-Restricted Yeast from WT, ISW2DEL and ISW2K215R strains We used MNase-seq to study genome-wide nucleosome positions under Calorie Restricted and Non-restricted Saccharomyces cerevisiae
Project description:In this study, we characterize the protein uptake and degradation pathways of S. cerevisiae to better understand its impact on protein secretion titers. We do find that S. cerevisiae can consume significant (g/L) quantities of whole proteins. Characterizing the systems with metabolomics and transcriptomics, we identify metabolic and regulatory markers that are consistent with uptake of whole proteins by endocytosis, followed by intracellular degradation and catabolism of substituent amino acids. Uptake and degradation of recombinant protein products may be common in S. cerevisiae protein secretion systems, and the current data should help formulate strategies to mitigate product loss.
Project description:The polyploid S. cerevisiae karyotypes were analyzed by array-CGH to identify the deletion or duplication of gene or chromosome during the strain construction and after experimental evolution.