Project description:Characterisation of genome-wide chromatin accessibility (tn5-digested, nucleosome depleted) from thymic Treg and thymic Tconv and to obtain the gene regulatory networks defining thymic Tregs in humans.
Project description:Chromatin accessibility was profiled by ATAC-seq in normal and glioblastoma-derived neural stem (GNS) cells, in self-renewing conditions and in response to differentiation stimulus with bone morphogenic protein (BMP).
Project description:A single hematopoietic stem cell can give rise to all blood cells with remarkable fidelity. Here, we define the chromatin accessibility and transcriptional landscape controlling this process in thirteen primary cell types that traverse the hematopoietic hierarchy. Exploiting the finding that enhancer landscapes better reflect cell identity than mRNA levels, we enable "enhancer cytometry" for accurate enumeration of pure cell types from complex populations. We further reveal the lineage ontogeny of genetic elements linked to diverse human diseases. In acute myeloid leukemia, chromatin accessibility reveals distinctive regulatory evolution in pre-leukemic HSCs (pHSCs), leukemia stem cells, and leukemic blasts. These leukemic cells demonstrate unique lineage infidelity, confirmed by single cell regulomes. We further show that pHSCs have a competitive advantage that is conferred by reduced chromatin accessibility at HOXA9 targets and is associated with adverse patient outcomes. Thus, regulome dynamics can provide diverse insights into human hematopoietic development and disease. ATAC-seq profiles of hematopoietic and leukemic cell types, across 13 normal hematopoietic cell types and 3 acute myeloid leukemia cell types. The complete data set contains a total of 132 samples.
Project description:In mammals, extensive chromatin reorganization is essential for reprogramming terminally committed gametes to a totipotent state during preimplantation development. However, the global chromatin landscape and its dynamics in this period remain unexplored. Here we report a genome-wide map of accessible chromatin in mouse preimplantation embryos using an improved assay for transposase-accessible chromatin with high throughput sequencing (ATAC-seq) approach with CRISPR/Cas9-assisted mitochondrial DNA depletion. We show that despite extensive parental asymmetry in DNA methylomes, the chromatin accessibility between the parental genomes is globally comparable after major zygotic genome activation (ZGA). Accessible chromatin in early embryos is widely shaped by transposable elements and overlaps extensively with putative cis-regulatory sequences. Unexpectedly, accessible chromatin is also found near the transcription end sites of active genes. By integrating the maps of cis-regulatory elements and single-cell transcriptomes, we construct the regulatory network of early development, which helps to identify the key modulators for lineage specification. Finally, we find that the activities of cis-regulatory elements and their associated open chromatin diminished before major ZGA. Surprisingly, we observed many loci showing non-canonical, large open chromatin domains over the entire transcribed units in minor ZGA, supporting the presence of an unusually permissive chromatin state. Together, these data reveal a unique spatiotemporal chromatin configuration that accompanies early mammalian development. Mouse preimplantation embryos were obtained from crosses of C57BL/6N and DBA/2N. ATAC-seq was performed in these embryos at various stages in preimplantation development.
Project description:Leukemia initiating cells (LICs) of acute myeloid leukemia (AML) may arise from self-renewing hematopoietic stem cells (HSCs) and from committed progenitors. However, it remains unclear how leukemia-associated oncogenes instruct LIC formation from cells of different origins and if differentiation along the normal hematopoietic hierarchy is involved. Here, using murine models with the driver mutations MLL-AF9 or MOZ-TIF2, we found that regardless of the transformed cell types, myelomonocytic differentiation to the granulocyte macrophage progenitor (GMP) stage is critical for LIC generation. Blocking myeloid differentiation through disrupting the lineage-restricted transcription factor C/EBPa eliminates GMPs, blocks normal granulopoiesis, and prevents AML development. In contrast, restoring myeloid differentiation through inflammatory cytokines “rescues” AML transformation. Our findings identify myeloid differentiation as a critical step in LIC formation and AML development, thus guiding new therapeutic approaches. Examination of chromatin accessibility in Cebpa knock-out and control conditions.
Project description:This is plate-based chromatin accessibility data set from 3 human foetal livers and bone marrow (18-21 PCW). It includes 4,001 cells before QC and 3,611 cells after QC.
Project description:Contrasting chromatin accessibility between activated and quiescent hepatic stellate cells to identify key gene networks for the activation process.
Project description:PIWI-interacting RNAs (piRNAs) mediate transposable element (TE) silencing at the transcriptional or post-transcriptional level in animal gonads. In the Drosophila ovary, Piwiâ??piRNA complexes (Piwiâ??piRISCs) repress TE transcription by modifying the chromatin state, such as H3K9me3 marks. Here, we demonstrate that Piwi physically interacts with linker histone H1. Depletion of Piwi decreases H1 density on target loci, leading to TE derepression. Loss of H1 results in gain of chromatin accessibility at target loci without affecting H3K9me3 and heterochromatin protein 1a (HP1a) density at the same loci. Piwi-mediated TE silencing also requires HP1a by regulating chromatin accessibility through its association with target loci. Thus, Piwiâ??piRISCs require both H1 and HP1a to repress TEs, and the silencing is correlated with the state of chromatin formation rather than H3K9me3 marks. These findings suggest that Piwiâ??piRISCs regulate the interaction of chromatin components with target loci to maintain silencing of the TE state through the modulation of chromatin accessibility. RNA levels, H1 and H3K9me3 occupancy, chromatin accessibility, and Piwi-associated small RNA levels in ovarian somatic cells (OSC) depleted of piRNA pathway components and H1.
Project description:Identification of open chromatin profiles at ESC, d1EpiLC and d2EpiLC. The accessible chromatin landscape of naive ESCs (Rex1GFPd2 mouse embryonic stem cell line; parental line; E14Tg2a) and their transition to EpiLCs over a two day period was determined using ATAC-seq.