Integrated detection of both 5-mC and 5-hmC by high-throughput tag sequencing technology highlights methylation reprogramming of bivalent genes during cellular differentiation
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ABSTRACT: This SuperSeries is composed of the SubSeries listed below. Refer to individual Series
Project description:5-methylcytosine (5-mC) can be oxidized to 5-hydroxymethylcytosine (5-hmC). Genome-wide profiling of 5-hmC thus far indicated 5-hmC may not only be an intermediate form of DNA demethylation but could also constitute an epigenetic mark per se. We describe a cost-effective and selective method to detect both the hydroxymethylation and methylation status of cytosines in more than 1.8 million MspI sites in the human genome. This method involves the selective glucosylation of 5-hmC residues, short-sequence tag generation and high-throughput sequencing. We tested this method by screening H9 human embryonic stem cells and their differentiated embroid body cells, and found that differential hydroxymethylation preferentially occur in bivalent genes during cellular differentiation. Especially, our results support hydroxymethylation can regulate key transcription regulators with bivalent marks through demethylation and affect cellular decision on choosing active or inactive state of these genes upon cellular differentiation. We developed a cost-effective and selective method to detect both the hydroxymethylation and methylation status of cytosines in more than 1.8 million MspI sites in the human genome. In order to validate the results generated by this method, we applied MeDIP-seq and hMeDIP-seq to screen H9 human embryonic stem cells in comparison with the newly developed method.
Project description:5-methylcytosine (5-mC) can be oxidized to 5-hydroxymethylcytosine (5-hmC). Genome-wide profiling of 5-hmC thus far indicated 5-hmC may not only be an intermediate form of DNA demethylation but could also constitute an epigenetic mark per se. We describe a cost-effective and selective method to detect both the hydroxymethylation and methylation status of cytosines in more than 1.8 million MspI sites in the human genome. This method involves the selective glucosylation of 5-hmC residues, short-sequence tag generation and high-throughput sequencing. We tested this method by screening H9 human embryonic stem cells and their differentiated embroid body cells, and found that differential hydroxymethylation preferentially occur in bivalent genes during cellular differentiation. Especially, our results support hydroxymethylation can regulate key transcription regulators with bivalent marks through demethylation and affect cellular decision on choosing active or inactive state of these genes upon cellular differentiation. We developed a cost-effective and selective method to detect both the hydroxymethylation and methylation status of cytosines in more than 1.8 million MspI sites in the human genome. In this method, we took advantage of the differential enzymatic sensitivities of the isoschizomers MspI and HpaII. HpaII cleaves only a completely unmodified site, any modification at either cytosine blocks the cleavage, while MspI recognizes and cleaves both 5-mC and 5-hmC, but not the newly discovered 5-formylcytosine (5-fC) and 5-carboxylcytosine (5-caC). Furthermore, beta-glucosyltransferase (beta-GT) can transfer a glucose to the hydroxyl group of 5-hmC and generate beta-glucosyl-5-hydroxymethylcytosine (5-ghmC) that blocks MspI digestion. Thus, either by combining beta-GT treatment with MspI digestion or simply applying MspI/HpaII digestion, short sequence tags generated can be used for inferring hydroxymethylation or methylation status in around 1.8 million cytosine sites in the human genome. We tested this method by screening H9 human embryonic stem cells and their differentiated embroid body cells.
Project description:5-methylcytosine (5-mC) can be oxidized to 5-hydroxymethylcytosine (5-hmC). Genome-wide profiling of 5-hmC thus far indicated 5-hmC may not only be an intermediate form of DNA demethylation but could also constitute an epigenetic mark per se. We describe a cost-effective and selective method to detect both the hydroxymethylation and methylation status of cytosines in more than 1.8 million MspI sites in the human genome. This method involves the selective glucosylation of 5-hmC residues, short-sequence tag generation and high-throughput sequencing. We tested this method by screening H9 human embryonic stem cells and their differentiated embroid body cells, and found that differential hydroxymethylation preferentially occur in bivalent genes during cellular differentiation. Especially, our results support hydroxymethylation can regulate key transcription regulators with bivalent marks through demethylation and affect cellular decision on choosing active or inactive state of these genes upon cellular differentiation. In order to explore the role of methylation and hyroxymethylation in regulating gene expression upon cellular differentiation to EBs, we examined the gene expression level in H9 human embryonic stem cells and their differentiated embroid body cells by Digital gene expression (DGE), respectively.
Project description:Linker histones are essential components of chromatin but the distributions and functions of many during cellular differentiation is not well understood. Here, we show that H1.5 binds to genic and intergenic regions, forming blocks of enrichment, in differentiated human cells from all three embryonic germ layers but not in embryonic stem cells. In differentiated cells, H1.5, but not H1.3, binds preferentially to genes that encode membrane and membrane-related proteins. Strikingly, 37% of H1.5 target genes belong to gene family clusters, groups of homologous genes that are located in proximity to each other on chromosomes. H1.5 binding is associated with gene repression and is required for SIRT1 binding, H3K9me2 enrichment and chromatin compaction. Depletion of H1.5 results in loss of SIRT1 and H3K9me2, increased chromatin accessibility, deregulation of gene expression and decreased cell growth. Our data reveal for the first time a specific and novel function for linker histone subtype H1.5 in maintenance of condensed chromatin at defined gene families in differentiated human cells. Examine human linker histone H1.5 (HIST1H1B) binding pattern in H1 hESCs and IMR90 fibroblasts
Project description:Tumor suppressor p53 promotes differentiation of human embryonic stem cells (hESCs), but an in-depth understanding of mechanism is lacking. Here, we define p53 functions in hESCs by genome wide profiling of p53 chromatin interactions and intersection with gene expression during early differentiation and in response to DNA damage. During differentiation, p53 targets and regulates a unique collection of genes, many of which encode transcription factors and developmental regulators with chromatin structure poised by OCT4 and NANOG and marked by repressive H3K27me3 in pluripotent hESCs. In contrast, genes associated with cell migration and motility are bound by p53 specifically after DNA damage. Surveillance functions of p53 in regulation of cell death and cell cycle genes are conserved during both DNA damage and differentiation. Our findings expand the registry of p53 -regulated genes in hESCs and define specific functions of p53 in opposing pluripotency, which are highly distinct from stress-induced p53 response in stem cells. Identification of p53 binding sites in hESC under three conditions : Pluripotent, DNA damaged, Differentiating
Project description:The control of cell identity is orchestrated by transcriptional and chromatin regulators in the context of specific chromosome structures. With the recent isolation of human naive embryonic stem cells (ESCs) representative of the ground state of pluripotency, it is possible to deduce this regulatory landscape in one of the earliest stages of human development. Here we generate cohesin ChIA-PET chromatin interaction data in naive and primed human ESCs and use it to reconstruct and compare the 3D regulatory landscapes of these two stages of early human development. The results reveal shared and stage-specific regulatory landscapes of topological domains and their subdomains, which consist of CTCF-CTCF/cohesin loops and enhancer-promoter/cohesin loops. The enhancer-promoter loop data reveal that genes with key roles in pluripotency are nearly always regulated by one or more super-enhancers, and show that these genes tend to occur in insulated neighborhoods. Our results reveal the key features of the 3D regulatory landscape of early human cells that form the foundation for embryonic development. ChIP-seq data from naive and primed human embroynic stem cells.
Project description:Unraveling complex signaling programs animating developmental lineage-decisions is pivotal to differentiate human pluripotent stem cells (hPSC) into pure populations of desired lineages for regenerative medicine. Developmental signals are strikingly temporally dynamic: BMP and Wnt initially specify primitive streak (progenitor to endoderm) yet 24 hours later suppress endoderm and induce mesoderm. At lineage bifurcations we show mutually-exclusive embryonic lineages are segregated through cross-repressive signals: TGFM-NM-2 and BMP/MAPK duel to respectively specify pancreas versus liver from endoderm. Unilateral endodermal differentiation requires blockade of alternative fates at every stage, revealing a universal developmental strategy for efficient differentiation and anterior-posterior patterning of diverse hPSC lines into highly-pure endodermal populations. This culminated in hPSC-derived hepatic progenitors that, for the first time, engraft long-term in genetically-unconditioned mouse livers and secrete human albumin. Finally, thirty transcriptional and chromatin state maps capturing endoderm commitment revealed endodermal enhancers reside in an unanticipated diversity of "pre-enhancer" chromatin states before activation. Endoderm RNA-seq and ChIP-seq data sets
Project description:The epithelial to mesenchymal transition (EMT) has been well recognized for many decades as an essential early step in the progression of primary tumors towards metastases. Widespread epigenetic reprogramming of DNA and histone modifications tightly regulates gene expression and cellular activity during carcinogenesis, and epigenetic therapy has been developed to design efficient strategies for cancer treatment. As the first oral agent approved for the clinical treatment of cancer, sorafenib has significant inhibitory effects on tumor growth and EMT. However, a detailed understanding of the underlying epigenetic mechanism remains elusive. In this manuscript, we performed a ChIP-Seq assay to evaluate the activity of sorafenib on the genome-wide profiling of histone modifications. We demonstrate that sorafenib largely reverses the changes in histone modifications that occur during EMT in A549 alveolar epithelial cells. Sorafenib also significantly reduces the coordinated epigenetic switching of critical EMT-associated genes in accordance with their expression levels. Furthermore, we show that sorafenib potentiates histone acetylation by regulating the expression levels of histone-modifying enzymes. Collectively, these findings provide the first evidence that sorafenib inhibits the EMT process through an epigenetic mechanism, which holds enormous promise for identifying novel epigenetic candidate diagnostic markers and drug targets for the treatment of human malignancies. To further explore the underlying epigenetic mechanisms of EMT regulation by sorafenib, we chose conventional markers of active euchromatin such as H3K9ac and H3K4me3, and contrasted their architecture with the repressive structures associated with H3K27me3 and H3K9me3. The profiling of these four selected histone modifications was performed using ChIP-seq on control, TGF-M-NM-21-treated and sorafenib-treated cells. We further performed pair-wise comparisons among the three treatment conditions to assess the changes in the histone modifications within specific genomic regions during EMT.
Project description:Comparison of H9 human embryonic stem cells, grown in chemically defined and animal-product free conditions, with their differentiated progeny - mesendodermal progenitors arisen as the result of changes made to chemically defined hESC growth conditions. Contributes to a larger work on the use of chemically defined growth conditions to direct hESC differentiation.
Project description:Gene expression microarray analysis of hESCs treated with BMP4 in chemically-defined medium, with and without inhibitors of Activin and FGF signalling (which maintain pluripotency), to investigate the induction of extra-embryonic tissue (trophectoderm) differentiation by BMP signalling.