The transcriptome-wide mapping of 2-methylthio-N6-isopentenyladenosine at single-base resolution by ReACT-seq
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ABSTRACT:
ORGANISM(S): Escherichia coli K-12
PROVIDER: GSE221930 | GEO | 2023/03/15
REPOSITORIES: GEO
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Project description:The transcriptome-wide mapping of 2-methylthio-N6-isopentenyladenosine at single-base resolution by ReACT-seq
| PRJNA916873 | ENA
Project description:While DNA N6-methyl-deoxyadenosine (6mA) is abundant in bacteria and protists, its presence and function in mammalian genomes have been less clear. We present Direct-Read 6mA sequencing (DR-6mA-seq), an antibody-independent method to measure 6mA at base-resolution with high sensitivity. DR-6mA-seq employs a unique mutation-based strategy to reveal 6mA sites as misincorporation signatures without any chemical or enzymatic modulation of 6mA. We validated DR-6mA-seq through successful mapping of the well-characterized G(6mA)TC motif in the E. coli DNA and identified 6mA sites in the mammalian mitochondrial DNA. As expected, when applying DR-6mA-seq to mammalian systems, we found that genomic DNA (gDNA) 6mA abundance is in general low in most mammalian tissues and cells; however, we did observe distinct gDNA 6mA sites in mouse testis and glioblastoma cells. DR-6mA-seq provides an enabling tool to detect 6mA at single-base resolution with high sensitivity for a comprehensive understanding of DNA 6mA in eukaryotes.
2023-12-28 | GSE213876 | GEO
Project description:5-methylcytosine (5mC), the predominant epigenetic modification on DNA, plays critical roles in mammalian development and is dysregulated in various human pathologies. In mammals, the TET family of dioxygenases can oxidize 5-methylcytosine (5mC) to 5-hydroxymethylcytosine (5hmC), 5-formylcytosine (5fC), and 5-carboxylcytosine (5caC) in a stepwise manner. 5fC and 5caC are selectively recognized and excised by mammalian thymine DNA glycosylase (TDG), and restored to normal cytosine through base excision repair (BER). Once 5mC/5hmC is converted to 5fC and/or 5caC, the modified cytosine is committed to demethylation through BER. Thus 5fC and 5caC most likely mark active demethylation in the mammalian genome. Here we introduce a genome-wide approach to obtain single-base resolution maps of 5fC and 5caC, respectively. We show that, in mouse embryonic stem cells (mESCs), 5fC and 5caC are preferentially generated at highly hypomethylated regions and more active enhancers. Moreover, 5caC-marked regions are characterized by the lowest methylation and highest enhancer activity among all modification sites associated with 5hmC, 5fC and 5caC, and are enriched adjacent to pluripotency transcription factor (TF)-binding motifs. These observations, together with the surprising lack of overlap between 5fC and 5caC sites, highlight a gradient of Tet-mediated 5mC oxidation activity at regulatory elements in tuning epigenetic dynamics11. DNA immunoprecipitation coupled chemical-modification assisted bisulfite sequencing (DIP-CAB-Seq) for Tdg fl/fl and Tdg-/- mESCs
2015-01-20 | E-GEOD-56429 | biostudies-arrayexpress
Project description:5-hydroxymethyluracil (5hmU) is a thymine base modification found in genomes of a diverse range of organisms. To explore the functional importance of 5hmU, we developed a method for the genome-wide mapping of 5hmU-modified loci based on a chemical tagging strategy for the hydroxymethyl group. We applied the method to generate genome-wide maps of 5hmU in parasitic protozoan Leishmania, where 5hmU forms enzymatically via hydroxylation of thymine. In the genus, another thymine modification 5-(β-glucopyranosyl) hydroxymethyluracil (base J) plays key roles during transcription. To elucidate relationships between 5hmU and base J, we also mapped base J loci by introducing a chemical tagging strategy for the glucopyranoside residue. Results: Observed 5hmU peaks were highly consistent among technical replicates, confirming the robustness of the method. 5hmU were particularly enriched in strand switch regions, telomeric regions and intergenic regions. Over 90% of 5hmU-enriched loci overlapped with base J-enriched loci, which occurred mostly within strand switch regions. We also identified loci comprising 5hmU but not base J. These 5hmU-specific loci were enriched with motifs consisting of a stretch of thymine bases and associated with higher RNA levels. Conclusions: By chemically detecting 5hmU we provide the first genome-wide map of 5hmU, which will help addressing the emerging interest in the role of 5hmU. The presence of 5hmU-specific loci may suggest that 5hmU has unique roles.
2016-12-15 | GSE83384 | GEO
Project description:Active DNA demethylation in mammals involves TET-mediated oxidation of 5-methylcytosine (5mC) to 5-hydroxymethylcytosine (5hmC), 5-formylcytosine (5fC) and 5-carboxycytosine (5caC). However, genome-wide detection of 5fC at single-base resolution remains challenging. Here we present a bisulfite-free method for the whole-genome analysis of 5fC, based on a selective chemical labeling of 5fC and subsequent C-to-T transition during PCR. Base-resolution 5fC maps reveal limited overlap with 5hmC, with 5fC-marked regions more active than 5hmC-marked ones. Utilization of cyclization-enabled C-to-T transition of 5fC (hence “fC-CET”) to obtain genome-wide map of 5fC at single-base resolution WT and TdgKO mES cell lines. Two non-enriched input DNAs (Input: preAI), two AI labeled samples (Input: AI), two pull-down output samples.
2015-09-07 | E-GEOD-66144 | biostudies-arrayexpress
Project description:We introduce m6A Selective Allyl Chemical labeling and Sequencing (m6A-SAC-Seq), a novel method for transcriptome-wide quantitative mapping of m6A at single-nucleotide resolution. The m6A-SAC-Seq employs a dimethyltransferase to selectively label m6A followed by introducing mutations with reverse transcriptase during sequencing. We identified the widespread distributions of m6A and quantitated their fractions in the transcriptome of HeLa, HEK293, HepG2, and human CD34+ hematopoietic stem/progenitor cells (HSPCs).
2022-01-20 | GSE162356 | GEO
Project description:Active DNA demethylation in mammals involves TET-mediated oxidation of 5-methylcytosine (5mC) to 5-hydroxymethylcytosine (5hmC), 5-formylcytosine (5fC) and 5-carboxycytosine (5caC). However, genome-wide detection of 5fC at single-base resolution remains challenging. Here we present a bisulfite-free method for the whole-genome analysis of 5fC, based on a selective chemical labeling of 5fC and subsequent C-to-T transition during PCR. Base-resolution 5fC maps reveal limited overlap with 5hmC, with 5fC-marked regions more active than 5hmC-marked ones.
2015-09-07 | GSE66144 | GEO
Project description:2’-O-methylation (Nm) is a prevalent post-transcriptional RNA modification present in many cellular RNAs and plays a critical role in modulating both the physical properties and regulation of eukaryotic RNAs. Studies of Nm modifications in RNA have long been hampered by a lack of effective mapping methods. Previously reported approaches can work well for detecting Nm modifications on abundant RNAs, but face challenges when applied to low-abundant RNAs, such as mRNA, lack stoichiometric information, and are challenged by issues of RNA sample degradation due to chemical treatment. Here, we present Nm-Mut-seq, a mutation signature-based Nm mapping method, which uses a custom reverse transcriptase (RT) that installs mutations at Am, Cm, and Gm-modified sites (Um is undetectable by this method). Our work provides a much-needed approach to detect Nm at base resolution in low abundant RNAs and to estimate the stoichiometry of each modified site transcriptome-wide.
2023-06-01 | GSE174518 | GEO
Project description:We introduce m6A Selective Allyl Chemical labeling and Sequencing (m6A-SAC-Seq), a novel method for transcriptome-wide quantitative mapping of m6A at single-nucleotide resolution. The m6A-SAC-Seq employs a dimethyltransferase to selectively label m6A followed by introducing mutations with reverse transcriptase during sequencing. We identified the widespread distributions of m6A and quantitated their fractions in the transcriptome of HeLa, HEK293, HepG2, and human CD34+ hematopoietic stem/progenitor cells (HSPCs).
2022-01-20 | GSE162340 | GEO
Project description:Various methyltransferases and demethylases catalyse methylation and demethylation of N6-methyladenosine (m6A) and N6,2'-O-dimethyladenosine (m6Am) but precise methylomes uniquely mediated by each methyltransferase/demethylase are still lacking. Here, we develop m6A-Crosslinking-Exonuclease-sequencing (m6ACE-seq) to map transcriptome-wide m6A and m6Am at quantitative single-base-resolution. This allows for the generation of a comprehensive atlas of distinct methylomes uniquely mediated by every individual known methyltransferase or demethylase. Our atlas reveals METTL16 to indirectly impact manifold methylation targets beyond its consensus target motif and highlights the importance of precision in mapping PCIF1-dependent m6Am. Rather than reverse RNA methylation, we find that both ALKBH5 and FTO instead maintain their regulated sites in an unmethylated steady-state. In FTO's absence, anomalous m6Am disrupts snRNA interaction with nuclear export machinery, potentially causing aberrant pre-mRNA splicing events.
| S-EPMC6904561 | biostudies-literature