Project description:We have generated open-chromatin profiles for liver, muscle, and hypothalamus of indicine cattle through ATAC-seq. Using robust methods for motif discovery, motif enrichment and transcription factor binding sites, we identified potential master regulators of the epigenomic profile in these three tissues, namely HNF1, MEF2 and NFYA factors, respectively. Integration with transcriptomic data allowed us to predict their target genes showing a significant recovery of confirmed targets across species.
Project description:BackgroundSpatiotemporal changes in the chromatin accessibility landscape are essential to cell differentiation, development, health, and disease. The quest of identifying regulatory elements in open chromatin regions across different tissues and developmental stages is led by large international collaborative efforts mostly focusing on model organisms, such as ENCODE. Recently, the Functional Annotation of Animal Genomes (FAANG) has been established to unravel the regulatory elements in non-model organisms, including cattle. Now, we can transition from prediction to validation by experimentally identifying the regulatory elements in tropical indicine cattle. The identification of regulatory elements, their annotation and comparison with the taurine counterpart, holds high promise to link regulatory regions to adaptability traits and improve animal productivity and welfare.ResultsWe generate open chromatin profiles for liver, muscle, and hypothalamus of indicine cattle through ATAC-seq. Using robust methods for motif discovery, motif enrichment and transcription factor binding sites, we identify potential master regulators of the epigenomic profile in these three tissues, namely HNF4, MEF2, and SOX factors, respectively. Integration with transcriptomic data allows us to confirm some of their target genes. Finally, by comparing our results with Bos taurus data we identify potential indicine-specific open chromatin regions and overlaps with indicine selective sweeps.ConclusionsOur findings provide insights into the identification and analysis of regulatory elements in non-model organisms, the evolution of regulatory elements within two cattle subspecies as well as having an immediate impact on the animal genetics community in particular for a relevant productive species such as tropical cattle.
Project description:This study is performed in the frame of a bigger study dedicated to the integrated analysis of the single-cell transcriptome and chromatin accessibility datasets of peripheral blood mononuclear cells (PBMCs) with a large-scale GWAS of 45 complex traits in Chinese Holstein cattle. In dairy cattle, lipopolysaccharide (LPS) is a crucial mediator of chronic inflammation to modulate immune responses. PBMCs include primary T and B cells, natural killer (NK) cells, monocytes (Mono), and dendritic cells (DC). It still remains unknown how LPS stimulated PBMCs at the single-cell level in dairy cattle. Therefore, the single-cell transcriptome and chromatin accessibility datasets in this study enable the further understanding and application of the cell types and functions of PBMCs and their responses to LPS stimulation in vitro in other studies.
Project description:Current catalogs of regulatory sequences in the human genome are still incomplete and lack cell type resolution. To profile the activity of human gene regulatory elements in diverse cell types and tissues in the human body, we applied single cell chromatin accessibility assays to 25 distinct human tissue types from multiple donors. The resulting chromatin maps comprising ~500,000 nuclei revealed the status of open chromatin for over 750,000 candidate cis-regulatory elements (cCREs) in 54 distinct cell types. We further delineated cell type-specific and tissue-context dependent gene regulatory programs, and developmental stage specificity by comparing with a recent human fetal chromatin accessibility atlas. We finally used these chromatin maps to interpret the noncoding variants associated with complex human traits and diseases. This rich resource provides a foundation for the analysis of gene regulatory programs in human cell types across tissues and organ systems.
Project description:Loss-of-function mutations in genes coding for subunits of the large, multifarious BRG1/BRM associated factor (BAF) chromatin remodeling complexes are frequently causative for cancer or developmental diseases1-5. Cells lacking the most frequently mutated subunits like the ATPase SMARCA4 typically exhibit drastic chromatin accessibility changes, especially of important regulatory regions6-12. However, so far it remains unknown how these changes are established over time, and whether they are causative for intra-complex synthetic lethalities abrogating the formation (SMARCC1-SMARCC2)8,13,14 or activity (SMARCA4-SMARCA2)15-17 of BAF complexes. Here, we utilize the dTAG system18 to induce acute degradation of BAF subunits in wild-type and BAF mutant backgrounds and analyze the resulting chromatin accessibility changes with high kinetic resolution. We observe that chromatin alterations are established faster than the duration of one cell cycle and that maintaining genome accessibility requires constant ATP-dependent remodeling. Completely abolishing BAF complex function by acute degradation of a synthetic lethal subunit in a paralog-deficient background results in a near-complete loss of chromatin accessibility at BAF-controlled sites, especially at super-enhancers, providing a mechanism for intra-complex synthetic lethalities.
Project description:We present FFPE-ATAC, a new ATAC-seq tool for chromatin accessibility profiling that decodes the chromatin accessibility from mouse FFPE tissue and clinical archived FFPE tissues. The FFPE-ATAC generates the high-quality chromatin accessibility profiles from clinical FFPE tissue sections with 5-20 µm thickness, and reveals the disease-associated regulatory elements in different types of FFPE archived tissue. FFPE-ATAC enables to decode the chromatin states regulating the gene regulation in the cancer and understand the epigenetic regulation in the translational studies.
Project description:Chromatin organization is a highly orchestrated process that influences gene expression, in part by modulating access of regulatory factors to DNA and nucleosomes. We found that the chromatin accessibility regulator HMGN1, a target of recurrent DNA copy gains in leukemia, controls myeloid differentiation. HMGN1 amplification was associated with increased accessibility, expression, and histone H3K27 acetylation of loci important for hematopoietic stem cell (HSC) function and AML, such as HoxA cluster genes. In vivo, HMGN1 overexpression was linked to decreased quiescence and increased HSC activity in bone marrow transplantation. HMGN1 overexpression also cooperated with the AML-ETO9a fusion oncoprotein to impair myeloid differentiation and enhance leukemia stem cell (LSC) activity. Inhibition of histone acetyltransferases CBP/p300 relieved the HMGN1-associated differentiation block. These data nominate factors that modulate chromatin accessibility as regulators of HSCs and LSCs and suggest that targeting HMGN1 or its downstream effects on histone acetylation could be therapeutically active in AML.
Project description:<p>Non-coding regions comprise most of the human genome and harbor a significant fraction of risk alleles for neuropsychiatric diseases, yet their functions remain poorly defined. We created a high-resolution map of non-coding elements involved in human cortical neurogenesis by contrasting chromatin accessibility and gene expression in the germinal zone and cortical plate of the developing cerebral cortex. To obtain a high resolution depiction of chromatin structure and gene expression in developing human fetal cortex, we dissected the post-conception week (PCW) 15-17 human neocortex into two major anatomical divisions to distinguish between proliferating neural progenitors and post mitotic neurons: (1) GZ: the neural progenitor-enriched region encompassing the ventricular zone (VZ), subventricular zone (SVZ), and intermediate zone (IZ) and (2) CP: the neuron-enriched region containing the subplate (SP), cortical plate (CP), and marginal zone (MZ). Tissues were obtained from three independent donors and three to four technical replicates from each tissue were processed for ATAC-seq to define the landscape of accessible chromatin and RNA-seq for genome-wide gene expression profiling.</p>
Project description:The transcription factor CTCF appears indispensable in defining topologically associated domain boundaries and maintaining chromatin loop structures within these domains, supported by numerous functional studies. However, acute depletion of CTCF globally reduces chromatin interactions but does not significantly alter transcription. Here we systematically integrated multi-omics data including ATAC-seq, RNA-seq, WGBS, Hi-C, Cut&Run, CRISPR-Cas9 survival dropout screening, time-solved deep proteomic and phosphoproteomic analyses in cells carrying auxin-induced degron at endogenous CTCF locus. Acute CTCF protein degradation markedly rewired genome-wide chromatin accessibility. Increased accessible chromatin regions were largely located adjacent to CTCF-binding sites at promoter regions and insulator sites and were associated with enhanced transcription of nearby genes. In addition, we used CTCF-associated multi-omics data to establish a combinatorial data analysis pipeline to discover CTCF co-regulatory partners in regulating downstream gene expression. We successfully identified 40 candidates, including multiple established partners (i.e., MYC) supported by all layers of evidence. Interestingly, many CTCF co-regulators (e.g., YY1, ZBTB7A) that have evident alterations of respective downstream gene expression do not show changes at their expression levels across the multi-omics measurements upon acute CTCF loss, highlighting the strength of our system to discover hidden co-regulatory partners associated with CTCF-mediated transcription. This study highlights CTCF loss rewires genome-wide chromatin accessibility, which plays a critical role in transcriptional regulation