Mus musculus
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA1064253 | ENA |
REPOSITORIES: ENA
Similar Datasets
Project description:Chromatin structure variations upon Tet inactivation
| PRJNA1066536 | ENA
Project description:Inborn defects in DNA repairare associated with complex developmental disorders whose causal mechanisms are poorly understood. Using an in vivo biotinylation tagging approach in mice, we show that the nucleotide excision repair (NER) structure-specific endonuclease ERCC1-XPF complex interacts with the insulator binding protein CTCF, the cohesin subunits SMC1A and SMC3 and with MBD2; the factors co-localize with ATRX at the promoters and control regions (ICRs) of imprinted genes during postnatal hepatic development. Loss of Ercc1or exposure to mitomycin C triggers the localization of CTCF to heterochromatin, the dissociation of the CTCF-cohesin complex and ATRXfrom promoters and ICRs,altered histone marks and the aberrant developmental expression of imprinted genes without altering DNA methylation. We propose that ERCC1-XPF cooperates with CTCF and the cohesinto facilitatet he developmental silencing of imprinted genes and that persistent DNA damage triggers chromatin changes that affect gene expression programs associated with NER disorders.
2017-04-04 | PXD005897 | Pride
Project description:Mammalian chromosomes are folded into intricate hierarchies of interaction domains, within which topologically associating domains (TADs) and CTCF-associated loops partition the physical interactions between regulatory sequences. Current understanding of chromosome folding largely relies on chromosome conformation capture (3C)-based experiments, where chromosomal interactions are detected as ligation products after crosslinking of chromatin. To measure chromosome structure in vivo, quantitatively and without relying on crosslinking and ligation, we have implemented a modified version of damID named damC. DamC combines DNA-methylation based detection of chromosomal interactions with next-generation sequencing and a biophysical model of methylation kinetics. DamC performed in mouse embryonic stem cells provides the first in vivo validation of the existence of TADs and CTCF loops and confirms 3C-based measurements of the scaling of contact probabilities. Combining damC with transposon-mediated genomic engineering shows that new loops can be formed between ectopically introduced and endogenous CTCF sites, which alters the partitioning of physical interactions within TADs. This orthogonal approach to 3C provides the first crosslinking- and ligation-free validation of the existence of key structural features of mammalian chromosomes and provides novel insights into how chromosome structure within TADs can be manipulated.
2019-06-03 | PXD013507 | Pride
Project description:<p>Metabolic lesions with pleiotropic effects on epigenetic regulation and other cellular processes are widely implicated in cancer, yet their oncogenic mechanisms remain poorly understood. Succinate dehydrogenase (SDH) deficiency causes a subset of gastrointestinal stromal tumors (GISTs) with DNA hyper-methylation. Here we associate this hyper-methylation with changes in chromosome topology that activate oncogenic programs. To investigate epigenetic alterations in this disease, we systematically mapped DNA methylation, CTCF insulators, enhancers and chromosome topology in KIT-mutant, PDGFRA-mutant and SDH-deficient GISTs. Although these respective subtypes share similar enhancer landscapes, we identified hundreds of putative insulators where DNA methylation replaced CTCF binding in SDH-deficient GISTs. We focused on disrupted insulators that partitions super-enhancers from FGF3, FGF4 and the KIT oncogene. Recurrent loss of this insulator alters locus topology in SDH-deficient GISTs, allowing aberrant physical interaction between enhancers and oncogenes. CRISPR-mediated excision of the corresponding CTCF motif in an SDH-intact model disrupted the boundary and up-regulated FGFs and KIT expression. Our findings reveal how a metabolic lesion destabilizes chromatin structure to facilitate the initiation and selection of epigenetic alterations that drive oncogenic programs in the absence of canonical mutations.</p>
| phs001906 | dbGaP
Project description:High order chromatin structure and DNA methylation are implicated in multiple development processes and diseases. Despite the recent developments of methods studying high order chromatin interactions, how DNA methylation is associated with high order chromatin structure is not clear. Currently, it is believed that the insulator protein CTCF binding is blocked by DNA methylation, occurring in its core binding site. Thus the disruption of CTCF binding will result in the ectopic assessment of enhancer in the isolated neighborhood. However, not all CTCF bears CpG sites in its core binding site and no integrated analysis has been applied to discover the relationship between DNA methylation and high order chromatin structure utilizing the DNA methylome data. Here we found the lowly methylated DNA methylation canyon are interacting with each other specifically in CD34+ CD38- hematopoietic stem and progenitor cells (HSPC) but not its differentiated progenitors. The DNA methylation canyon interactions are enriched for H3K27me3 mark and represent a different category of interactions other than looped domain mediated by CTCF extrusion mechanism. We also found these canyons are contributing to the active HOX gene expression acting as scaffolds for gene expression rather enhancers. Disruption of canyon interaction with CTCF deletion and whole canyon deletion result in a great compromise of self-renewal ability of HSPC and the decrease of expression of active HOXA/B gene.
2017-11-24 | GSE107024 | GEO
Project description:Mammalian genomes are subjected to epigenetic modifications, including cytosine methylation by DNA methyltransferases (Dnmt) and further oxidation by Ten-eleven-translocation (Tet) family of dioxygenases. Cytosine methylation plays key roles in multiple processes such as genomic imprinting and X-chromosome inactivation. However, the functional significance of cytosine methylation and the further oxidation has remained undetermined in mouse embryogenesis. Here we show that global inactivation of all three Tet genes in mice led to consistent defects in gastrulation. The defects include reduced specification of the axial mesoderm and paraxial mesoderm, mimicking phenotypes in embryos with gain-of-function Nodal signaling, a cardinal cue for gastrulation. Introduction of a single mutant allele of Nodal in the Tet mutant background partially restored patterning, suggesting that hyperactive Nodal signaling is a leading cause for the gastrulation failure of Tet mutants. Increased Nodal signaling is likely due to diminished expression of the Lefty1 and Lefty2 genes, inhibitors of Nodal signaling. Moreover, reduction in the Lefty gene expression can be ascribed to elevated DNA methylation as both Lefty-Nodal signaling and normal morphogenesis are largely restored in Tet-deficient embryos when the Dnmt3a and Dnmt3b genes are disrupted. Additionally, specific inactivation of Tet by point mutations abolishing the dioxygenase activity causes similar molecular and gastrulation abnormalities. Taken together, our results show that Tet-mediated DNA oxidation modulates the Lefty-Nodal signaling by promoting demethylation of the shared target genes with Dnmt3a and Dnmt3b. These findings reveal a fundamental epigenetic mechanism featuring dynamic DNA methylation and demethylation and their role in the regulation of key signaling in body plan formation during early embryogenesis. Examine RNA expression and DNA methylation differences between Tet-null and wild type samples of mouse epiblast in E6.5.
2016-10-27 | E-GEOD-76261 | biostudies-arrayexpress
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:The vertebrate body plan and organs are shaped during a highly conserved embryonic phase called the phylotypic stage, however the mechanisms that guide the epigenome through this transition and their evolutionary conservation remain elusive. Here we report widespread DNA demethylation of thousands of enhancers during the phylotypic period in zebrafish, Xenopus and mouse. These dynamic enhancers are linked to essential developmental genes that display coordinated transcriptional and epigenomic changes in the diverse vertebrates during embryogenesis. Phylotypic stage-specific binding of Tet proteins to (hydroxy)methylated DNA, and enrichment of hydroxymethylcytosine on these enhancers, implicated active DNA demethylation in this process. Furthermore, loss of function of Tet1/2/3 in zebrafish caused reduced chromatin accessibility and increased methylation levels specifically on these enhancers, indicative of DNA methylation being an upstream regulator of phylotypic enhancer function. Overall, our study reveals a novel regulatory module associated with the most conserved phase of vertebrate embryogenesis and uncovers an ancient developmental role for the Tet dioxygenases.
2016-01-27 | PXD001164 | Pride
Project description:Regulation of gene expression underlies the establishment and maintenance of cell identity. Chromatin structure and gene activity are linked. Recently CTCF anchored loops have been described as major features of chromatin organisation. However, the dynamics and role for these structures in differentiation is unknown. We used Tethered Chromatin Conformation Capture (TCC) to assess for the dynamics of CTCF-anchor loop formation upon differentiation of mouse embryonic stem cells (ESC) and neural stem cells (NSC).
2018-11-08 | E-MTAB-4870 | biostudies-arrayexpress
Project description:DNA methylation in the promoters of plant genes sometimes leads to transcriptional repression, and the wholesale removal of DNA methylation as seen in methyltransferase mutants results in drastic changes in gene expression and severe developmental defects. However, many cases of naturally-occurring DNA methylation variations have been reported, whereby the altered expression of differentially methylated genes is responsible for agronomically important traits. The ability to manipulate plant methylomes to generate populations of epigenetically distinct individuals could provide invaluable resources for breeding and research purposes. Here we describe “epimutagenesis”, a novel method to rapidly generate variation of DNA methylation through random demethylation of the Arabidopsis thaliana genome. This method involves the expression of a human Ten-eleven translocation (TET) enzyme, and results in widespread hypomethylation that can be inherited to subsequent generations, mimicking mutants in the maintenance DNA methyltransferase met1. Application of TET-mediated epimutagenesis to agriculturally significant plants may result in differential expression of alleles normally silenced by DNA methylation, uncovering previously hidden phenotypic variations.
2018-03-02 | GSE93024 | GEO