Project description:Chromatin accessibility was assayed in wildtype or Dppa2 knockout ESC after 26 days of release of the trigger imposed by epigenetic editing. Samples were collected in two clonal knockout and wildtype lines after sorting at FACS of cells which maintained a repressive Esg1-tdTomato (TOMneg) reporter expression after 26 days of DOX washout (release of the trigger).
Project description:FACS purified cells from differentiation day 14-15 cells from 3 BAC transgenic mESC lines: Hes::GFP (early), Nurr1::GFP (mid), and Pitx3::YFP (late) DA neuron development reporter lines
Project description:FACS purified cells from differentiation day 14-15 cells from 3 BAC transgenic mESC lines: Hes::GFP (early), Nurr1::GFP (mid), and Pitx3::YFP (late) DA neuron development reporter lines All three lines were differentiated towards the midbrain dopamine phenotype, and FACS purification was performed at D14-15, and then subject to global transcriptome analysis
Project description:Early mammalian development entails widespread epigenome remodeling, including DNA methylation erasure and reacquisition, which facilitates developmental competence. To uncover the mechanisms that orchestrate global and focal DNA methylation (DNAme) dynamics, we coupled a single-cell ratiometric DNAme reporter with unbiased CRISPR screening. We identify key genes and regulatory pathways that drive developmental DNA hypomethylation, and characterise roles for Cop1 and Dusp6. We also identify Dppa2 and Dppa4 as essential safeguards of focal epigenetic states during (re)programming phases. In their absence, developmental genes and evolutionary young LINE1 elements lose H3K4me3 and gain ectopic de novo DNA methylation. Consequently, lineage-associated genes (and LINE1) acquire a repressive epigenetic memory in pluripotent cells, which renders them incompetent for activation during future lineage-specification. Dppa2/4 thereby sculpt a permissive epigenome for development by targeting H3K4me3 to counteract de novo methylation during (re)programming; a function that has been co-opted by evolutionary young LINE1 to evade epigenetic decommissioning.
Project description:Profiling of H3K4me1 genome wide occupancy in mESC WT, LSD1 KO, and rescued with WT LSD1 (RO) and with mutant LSD1 (AK) to explore the effects of LSD1 on histone methylation.
Project description:This SuperSeries is composed of the following subset Series: GSE31581: ECAT15-2/Dppa2 deficient ESCs GSE31582: ECAT15-2/Dppa2 transgenic rescue into ECAT15-2/Dppa2 deficient ESCs GSE31583: Lung of ECAT15-2/Dppa2 deficient embryo at E18.5 Refer to individual Series
Project description:Epigenetic priming factors establish a permissive epigenetic landscape which is not required until a later developmental or physiological time point, temporally uncoupling the presence of these factors with their phenotypic effects. One classic example of epigenetic priming is in the context of bivalent chromatin, found in pluripotent stem cells and early embryos at key developmental gene promoters marked by both activating-associated H3K4me3 and repressive-associated H3K27me3 histone modifications. It is currently unknown how these bivalent domains are targeted, or precisely how they impact on lineage commitment. Here we show that the small heterodimerising non-enzymatic DNA binding proteins Developmental Pluripotency Associated 2 (Dppa2) and 4 (Dppa4) act as epigenetic priming factors to establish bivalency at a subset of developmental genes. Dppa2/4 localise to the +1 nucleosome position of bivalent genes and while they are not required for pluripotency in embryonic stem cells (ESCs), double knockout cells fail to exit pluripotency and to differentiate efficiently, with delays in upregulating bivalently marked lineage genes. Proteomics reveal that Dppa2/4 interact on chromatin with members of the COMPASS and Polycomb complexes important for H3K4me3 and H3K27me3 deposition, respectively. Epigenetic profiling reveals a striking loss of H3K4me3, H3K27me3, and their associated enzymatic machinery at a significant subset of bivalent promoters in Dppa2/4 mutants, in addition to loss of H2A.Z and chromatin accessibility. In wild-type ESCs, these “Dppa2/4-dependent” bivalent promoters are characterised by low H3K4me3 enrichment and breadth, near-absent expression levels and initiating but not elongating RNA polymerase. Notably, Dppa2/4-dependent promoters are less evolutionarily conserved suggesting that they lack additional safeguard measures to maintain bivalency at these genes in the absence of Dppa2/4. Concomitantly with the loss of bivalency, Dppa2/4-dependent bivalent promoters gain DNA methylation and consequently are no longer able to be effectively activated upon ESC differentiation, leading to defects in cell fate acquisition. Our findings reveal a targeting principle for bivalency to developmental gene promoters poising them for future lineage specific gene activation.