Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Distinguishing active versus passive DNA demethylation using Illumina MethylationEPIC BeadChip microarrays

ABSTRACT: The 5-carbon position on cytosine nucleotides preceding guanines in genomic DNA (CpG) are common targets for DNA methylation (5mC). Genomic locations enriched for 5mC contribute to the regulation of chromatin structure and gene expression. While largely stable, massive waves of DNA demethylation are observed in key developmental windows in mammals. Additionally, DNA methylation is therapeutically targeted in cancer via DNA methyltransferase inhibition, in part to reverse abnormal silencing of tumor suppressor genes. DNA methylation removal can occur through both active and passive mechanisms. Ten-eleven translocation enzymes (TETs) oxidize 5mC in a stepwise manner to 5-hydroxymethylcytosine (5hmC), 5-formylcytosine (5fC), and 5-carboxylcytosine (5caC). These oxidized cytosine forms have reported function in gene regulation and also serve as intermediates in an active 5mC removal process that involves the base excision repair pathway. 5mC can also be removed passively through sequential cell divisions in the absence of DNA methylation maintenance. Distinguishing active versus passive 5mC removal on a genome-wide scale remains a challenge. In this chapter, we describe approaches that couple TET-assisted bisulfite (TAB) and oxidative bisulfite (OxBS) conversion to the Illumina MethylationEPIC BeadChIP (EPIC array) and show how these technologies can be used to distinguish active versus passive DNA demethylation. We also describe integrative bioinformatics pipelines to facilitate this analysis.

ORGANISM(S): Homo sapiens

PROVIDER: GSE145113 | GEO | 2021/01/31

REPOSITORIES: GEO

ACCESS DATA

Json Xml

Dataset's files

Source:

			Action	DRS
		Other

Items per page:

1 - 1 of 1

Similar Datasets

Active DNA Demethylation by DNMT3A and DNMT3B - Mechanistic Aspect and In Vivo Evidence

Project description:The DNA methylation program is at the bottom layer of the epigenetic regulatory cascade of vertebrate development. While the methylation at C-5 position of the cytosine (C) residues on the vertebrate genomes is achieved through the catalytic activities of the DNA methyltransferases (DNMTs), the conversion of the methylated cytosine (5mC) could be accomplished by the combined actions of the TET enzyme and DNA repair. Interestingly, it has been found recently that the mouse and human DNMTs also possess active DNA demethylation activity in vitro in a Ca2+- and redox condition-dependent manner. We report here the study of tracking down the fate of the methyl group removed from 5mC on DNA during in vitro demethylation reaction by mouse de novo DNMTs, i.e. DNMT3A and DNMT3B. Remarkably, the methyl group becomes covalently linked to the catalytic cysteines utilized by the two de novo DNMTs in their DNA methylation reactions. Thus, the forward and reverse reactions of DNA methylations by the DNMTs may utilize the same cysteine residue(s) as the active site despite of their distinctive pathways. Secondly, we demonstrate that active DNA demethylation of a heavily methylated GFP reporter plasmid by ectopically expressed DNMT3A or DNMT3B occurs in vivo in transfected human HEK 293 cells in culture. Furthermore, the extent of DNA demethylation by the DNMTs in this cell-based system is affected by Ca2+ homeostasis as well as by mutation of their putative active cysteines. These findings substantiate the roles of the vertebrate DNMTs as double-edged swords in DNA methylation-demethylation in vitro as well as in a cellular context.

2022-02-24 | PXD003401 | Pride

Comparative DNA methylation profiling of human monocyte-derived macrophages and dendritic cells

Project description:In mammals, the dynamics of DNA methylation, in particular the regulated, active removal of cytosine methylation has remained a mystery, partly due to the lack of appropriate model systems to study DNA demethylation. Previous work largely focused on proliferating cell types that had been mitotically arrested using pharmacological inhibitors to distinguish between active and passive mechanisms of DNA demethylation. Here, we characterised this epigenetic phenomenon in a natural setting of post-mitotic cells: the differentiation of human peripheral blood monocytes into macrophages or dendritic cells which proceeds without cell division. We identified many novel examples of active DNA demethylation using a global, comparative CpG methylation profiling approach and characterised accompanying transcriptional and epigenetic events at these sites during monocytic differentiation. Keywords: MCIp-on-Chip; comparative genomic hybridization

2010-06-07 | GSE19395 | GEO

Active Demethylation of Both Maternal and Paternal Genomes in Mouse Zygotes

Project description:The epigenomes of mammalian sperm and oocytes, characterized by gamete-specific 5-methylcytosine (5mC) patterns, are reprogrammed in early embryogenesis to establish full developmental potential. It is broadly accepted that the paternal genome is actively demethylated in the zygote while the maternal genome undergoes passive demethylation thanks to DNA replication over the subsequent cleavage divisions. Here we reveal that both maternal and paternal genomes undergo widespread active and passive demethylation in the pronuclear zygote before the first mitotic division. Whereas the passive demethylation requires DNA replication, the active demethylation relies on enzymatic oxidation of 5mC, as deletion of the DNA dioxygenase, Tet3, but not the inhibition of replication, blocks the active demethylation. At actively demethylated loci, 5mCs appear to be processed to unmodified cytosines in a manner independent of the DNA glycosylase TDG. These observations suggest the occurrence of genuine active demethylation in both parental genomes following fertilization. An extra supportive Tet3 knock-out female pronuclear sample related to experiment Series GSE56650.

2016-09-01 | E-GEOD-60777 | biostudies-arrayexpress

Base-resolution maps of 5-formylcytosine and 5-carboxylcytosine reveal genome-wide DNA demethylation dynamics

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

Active Demethylation of Both Maternal and Paternal Genomes in Mouse Zygotes

2016-09-01 | GSE60777 | GEO

Single-base resolution analysis of active DNA demethylation using methylase-assisted bisulfite sequencing

Project description:Active DNA demethylation in mammals involves TET-mediated iterative oxidation of 5-methylcytosine (5mC)/5-hydroxymethylcytosine (5hmC) and subsequent excision repair of highly oxidized cytosine bases 5-formylcytosine (5fC)/5-carboxylcytosine (5caC) by Thymine DNA glycosylase (TDG). However, quantitative and high-resolution analysis of active DNA demethylation activity remains challenging. Here we describe M.SssI methylase-assisted bisulfite sequencing (MAB-seq), a method that directly maps 5fC/5caC at single-base resolution. Genome-wide MAB-seq allows systematic identification of 5fC/5caC in Tdg-depleted embryonic stem cells, thereby generating a base-resolution map of active DNA demethylome. A comparison of 5fC/5caC and 5hmC distribution maps indicates that catalytic processivity of TET enzymes correlates with local chromatin accessibility. MAB-seq also reveals strong strand asymmetry of active demethylation within palindromic CpGs. Integrating MAB-seq with other base-resolution mapping methods enables quantitative measurement of cytosine modification states at key transitioning steps of active demethylation pathway, and reveals a regulatory role of 5fC/5caC excision repair in active DNA demethylation cascade. Analysis of 5fC/5caC excision repair-dependent active DNA demethylome by MAB-seq in mouse embryonic stem cells.

2014-11-02 | E-GEOD-62631 | biostudies-arrayexpress

Active and passive mechanisms of 5mC and 5hmC removal in human T lymphocytes

Project description:In mammals, the 5’-methylcytosine (5mC) modification in the genomic DNA contributes to the dynamic control of gene expression. 5mC erasure is required for the activation of developmental programs and occurs either by passive dilution through DNA replication, or by enzymatic oxidation of the methyl mark to 5-hydroxymethylcytosine (5hmC), followed by passive dilution or further oxidation and active removal. For most biological systems, the relative contribution of active and passive processes of 5mC and 5hmC erasure to the regulation of cell physiology remains poorly defined. Using primary human T lymphocytes as a model of activation-driven cell proliferation and differentiation, we found that DNA demethylation-dependent processes were central in the efficient acquisition of cytokine gene expression by T lymphocytes. As for the underlying mechanism, T cells appeared to rely primarily on the conversion of 5mC into 5hmC, followed by passive, replication-dependent dilution of the 5hmC mark, although active 5hmC removal also occurred during the early stages of activation of naïve, but not memory T lymphocytes. Our data are consistent with a model in which 5hmC is required in quiescent naive T lymphocytes for the establishment and maintenance of regulatory regions poised for rapid response to physiological stimuli. However, cell cycle progression is the primary mechanism to relieve epigenetic constraints in memory T cells.

2019-05-01 | GSE113884 | GEO

5mC Oxidation by Tet2 Modulates Enhancer Activity and Timing of Transcriptome Reprogramming during Differentiation

Project description:In mammals, cytosine methylation (5mC) is widely distributed throughout the genome but is notably depleted from active promoters and enhancers. While the role of DNA methylation in promoter silencing has been well documented, the function of this epigenetic mark at enhancers remains unclear. Recent experiments have demonstrated that enhancers are enriched for 5-hydroxymethylcytosine (5hmC), an oxidization product of the Tet family of 5mC dioxygenases and an intermediate of DNA demethylation. These results support the involvement of Tet proteins in the regulation of dynamic DNA methylation at enhancers. By mapping DNA methylation and hydroxymethylation at base resolution, we find that deletion of Tet2 causes extensive loss of 5hmC at enhancers, accompanied by enhancer hypermethylation, reduction of enhancer activity, and delayed gene induction in the early steps of differentiation. Our results reveal that DNA demethylation modulates enhancer activity, and its disruption influences the timing of transcriptome reprogramming during cellular differentiation. We performed traditional bisulfite sequencing, TAB-Seq, RNA-Seq, and ChIP-Seq for 6 histone modifications in two biological replicates of wild-type, Tet1-/-, and Tet2-/- mouse ES cells. We also performed RNA-Seq analysis during a timecourse of differentiation to neural progenitor cells.

2014-09-25 | E-GEOD-48519 | biostudies-arrayexpress

Nanopore sequencing and data analysis for base-resolution genome-wide 5-methylcytosine profiling

Project description:Whole-genome bisulfite sequencing (WGBS) is currently the gold standard for DNA methylation (5-methylcytosine, 5mC) profiling, however the destructive nature of sodium bisulfite results in DNA fragmentation and subsequent biases in sequencing data. Such issues have led to the development of bisulfite-free methods for 5mC detection. Nanopore sequencing is a long read non-destructive approach that directly analyzes DNA and RNA fragments in real time. Recently, computational tools have been developed that enable base-resolution detection of 5mC from Oxford Nanopore sequencing data. In this chapter we provide a detailed protocol for preparation, sequencing, read assembly and analysis of genome-wide 5mC using Nanopore sequencing technologies.

2021-12-03 | GSE179673 | GEO

Single base resolution analysis of 5-formyl and 5-carboxyl cytosine reveals the actual promoter DNA methylation dynamics in embryonic stem cells [RRBS]

Project description:DNA methylation is catalysed by DNA methyltransferases (DNMTs) and is necessary for a correct embryonic development. On the other hand, the DNA demethylation is mediated by the Ten Eleven Translocation (Tet) proteins through oxidation of 5-methyl cytosine (5mC) to 5-hydroxyl (5hmC), 5-formyl (5fC) and 5-carboxyl (5caC) cytosine, and by the Thymine-DNA glycosylase (TDG) that excises the 5fC and 5caC. In embryonic stem cells (ESCs), gene promoters are maintained in an hypomethylated state, but the dynamics of this phenomenon still remains unknown. Here we present a genome-wide approach, named methylation-assisted bisulfite sequencing (MAB-Seq) that enables single-base resolution mapping of 5fC and 5caC and measuring of their relative abundance. Application of this method to mouse ESCs exposed the presence of 5fcaC residues on the hypomethylated promoters of the expressed genes, revealing an active DNA demethylation mechanism since the loss of TDG leads to an increase of 5fC/5caC. We also show that TDG is actually bound on these regions and that co-localizes and interacts with Tet1. We moreover demonstrate, by reduced representation of bisulfite sequencing (RRBS), that active promoters are actually demethylated by a Tet-dependent mechanism and that Dnmt1 and Dnmt3a are responsible of this DNA methylation. Our work shows the whole-genome map of 5fC and 5caC at single base resolution in ESCs, it demonstrates in detail the DNA methylation dynamics occurring on expressed gene promoters and identifies the key players of this mechanism. Furthermore, we provide a new tool (MAB-Seq) that can be broadly used in all biological contexts for epigenetics study involving identification and quantification of 5fC and 5caC at single base resolution. Methylation-assisted bisulfite sequencing (MAB-Seq) of E14 embryonic stem cells (ESCs), Biotag ChIP-Seq of Tdg and Reduced representation Bisulfite Sequencing (RRBS) in E14 ESCs.

2015-02-10 | E-GEOD-55659 | biostudies-arrayexpress

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data