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PROVIDER: PRJNA824446 | ENA |
REPOSITORIES: ENA
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Project description:Active DNA demethylation controls transgenerational epigenetic stability
| PRJNA700573 | ENA
Project description:Active DNA demethylation is an important epigenetic phenomenon in many eukaryotes. In Arabidopsis thaliana, ROS1, a 5-methylcytosine DNA glycosylase, is responsible for active DNA demethylation via a base excision repair process. Here, we found that Bromodomain and ATPase domain-containing protein 1 (BRAT1) associates with BRP1 (BRAT1 Partner 1) and forms a tight BRAT1–BRP1 complex required for DNA demethylation. To identify hypermethylated loci at the whole-genome level in brat1, brp1, and ros1, we performed whole-genome bisulfite sequencing. Compare the DNA methylation profiles of 10-day old seedlings materials of mutants (brat1, brp1, and ros1) to wild type by whole-genome bisulfite sequencing.
2015-04-14 | E-GEOD-67798 | biostudies-arrayexpress
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
Project description:Genome-wide DNA demethylation is a unique feature of mammalian development and naïve pluripotent stem cells. So far, it was unclear how mammals specifically achieve global DNA hypomethylation, given the high conservation of the DNA (de-)methylation machinery among vertebrates. We found that DNA demethylation requires TET activity but mostly occurs at sites where TET proteins are not bound suggesting a rather indirect mechanism. Among the few specific genes bound and activated by TET proteins was the naïve pluripotency and germline marker Dppa3 (Pgc7, Stella), which undergoes TDG dependent demethylation. The requirement of TET proteins for genome-wide DNA demethylation could be bypassed by ectopic expression of Dppa3. We show that DPPA3 binds and displaces UHRF1 from chromatin and thereby prevents the recruitment and activation of the maintenance DNA methyltransferase DNMT1. We demonstrate that DPPA3 alone can drive global DNA demethylation when transferred to amphibians (Xenopus) and fish (medaka), both species that naturally do not have a Dppa3 gene and exhibit no post-fertilization DNA demethylation. Our results show that TET proteins are responsible for active and - indirectly also for - passive DNA demethylation; while TET proteins initiate local and gene-specific demethylation in vertebrates, the recent emergence of DPPA3 introduced a unique means of genome-wide passive demethylation in mammals and contributed to the evolution of epigenetic regulation during early mammalian development.
2020-10-12 | PXD019794 | Pride
Project description:DNA methylation is an important epigenetic modification involved in many biological processes, and active DNA demethylation plays critical roles in regulating expression of genes and anti-silencing of transgenes. In this study, we isolated mutations in one arabidopsis gene, ROS5, which causes the silencing of transgenic 35S-NPTII because of DNA hypermethylation, but no effect on transgenic RD29A-LUC. ROS5 encodes an atypical small heat shock protein. ROS5 can physically interact with IDM1 and is required for preventing DNA hypermethylation of some endogenous genes that are also regualated by IDM1 and ROS1. We propose that ROS5 may regulate active DNA demethylation by interacting with IDM1, thereby creating a friendly chromatin environment that facilitates the binding of ROS1 to erase DNA methylation.
2014-08-28 | E-MTAB-4323 | biostudies-arrayexpress
Project description:Epigenetic reprogramming including demethylation of DNA occurs in mammalian primordial germ cells (PGCs) and in early embryos, and is important for the erasure of imprints and epimutations, and the return to pluripotency. The extent of this reprogramming and its molecular mechanisms are poorly understood. We previously showed that the cytidine deaminases Aid and Apobec1 can deaminate 5-methylcytosine in vitro and in E coli, and in the mouse are expressed in tissues in which demethylation occurs. Here we profiled DNA methylation throughout the genome by unbiased bisulfite Next Generation Sequencing (BS-Seq) in wildtype and Aid deficient PGCs at E13.5. Wildtype PGCs revealed dramatic genome-wide erasure of methylation to a level below that of methylation deficient (Np95-/-) ES cells, with female PGCs being less methylated than male ones. By contrast, Aid deficient PGCs were up to three times more methylated than wildtype ones; this substantial difference occurred throughout the genome, with introns, intergenic regions and transposons being relatively more methylated than exons. Relative hypermethylation in Aid deficient PGCs was confirmed by analysis of individual loci in the genome. Our results reveal that erasure of DNA methylation in the germ line is a global process, hence limiting the potential for transgenerational epigenetic inheritance. Aid deficiency interferes with genome-wide erasure of DNA methylation patterns, suggesting that Aid has a critical function in epigenetic reprogramming and potentially in restricting the inheritance of epimutations in mammals. Comparison of methylation in wild-type and Aid deficient mouse tissues
2010-01-26 | E-GEOD-19960 | biostudies-arrayexpress
Project description:The 5-methylcytosine DNA glycosylase/lyase REPRESSOR OF SILENCING 1 (ROS1)-mediated active DNA demethylation is critical for shaping the genomic DNA methylation landscape in Arabidopsis. Whether and how the stability of ROS1 may be regulated by post-translational modifications is unknown. Using a methylation-sensitive PCR (CHOP-PCR)-based forward genetic screen for Arabidopsis DNA hypermethylation mutants, we identified the SUMO E3 ligase SIZ1 as a critical regulator of active DNA demethylation. Dysfunction of SIZ1 leads to hyper-methylation at approximately one thousand genomic regions. SIZ1 physically interacts with ROS1 and mediates the SUMOylation of ROS1. The SUMOylation of ROS1 is reduced in siz1 mutant plants. Compared to that in wild type plants, the protein level of ROS1 is significantly decreased, even though there is an increased level of ROS1 transcripts in siz1 mutant plants. Our results suggest that SIZ1 positively regulates active DNA demethylation by promoting the stability of ROS1 protein through SUMOylation.
2020-06-14 | GSE152425 | GEO
Project description:It has become clear that DNA repair factors function not only in the maintenance of genomic integrity but also in active DNA demethylation and epigenetic gene regulation. This dual role raises the question if phenotypic abnormalities resulting from deficiency of DNA repair factors are due to DNA damage or impaired DNA demethylation. Here we investigate the bifunctional DNA glycosylases/lyases NEIL1 and NEIL2, which act in repair of oxidative lesions and in epigenetic demethylation.
2019-09-16 | GSE130082 | GEO
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
Project description:Foxp3+ regulatory T cells (Treg cells) are essential for immune system homeostasis and suppression of excessive immune responses. Both TGF-β signaling and epigenetic modifications are important in the regulation of Foxp3 induction, but whether TGF-β signaling participates in the epigenetic regulation of Foxp3 has not been fully clarified. Here, we show that Uhrf1, which is induced by TCR stimulation and regulated by TGF-β signaling, controls Foxp3 methylation and iTreg cell differentiation. T cell-specific ablation of Uhrf1 led to Treg-biased differentiation in naïve T cells, with DNA hypomethylation upon TCR stimulation, and these Foxp3+ T cells had suppressive function. Uhrf1 maintained Foxp3 DNA methylation by recruiting Dnmt1 during cell division upon TCR stimulation. TGF-β treatment led to passive demethylation of the Foxp3 promoter to initiate its expression. Mechanistically, Uhrf1 was phosphorylated upon TGF-β stimulation and largely sequestered in the cytoplasm. Phosphorylated Uhrf1 underwent proteasomal degradation through inhibition of Usp7-mediated deubiquitination. Collectively, our study reveals a novel epigenetic mechanism of TGF-β-mediated iTreg cell differentiation regulated by Uhrf1 and reveals the differential role of active and passive demethylation in Foxp3 induction and stability.
2019-09-08 | GSE128480 | GEO