Project description:Regulation of genes that initiate and amplify inflammatory programs of gene expression is achieved by signal-dependent exchange of co-regulator complexes that function to read, write and erase specific histone modifications linked to transcriptional activation or repression. Here, we provide evidence for an unexpected role of trimethylated histone H4 lysine 20 (H4K20me3) as a repression checkpoint that restricts expression of toll like receptor 4 (TLR4) target genes in macrophages. H4K20me3 is deposited at the promoters of a subset of these genes by the SMYD5 histone methyltransferase through its association with NCoR co-repressor complexes. Signal-dependent erasure of H4K20me3 is required for effective gene activation and is achieved by NF-KB-dependent delivery of the histone demethylase PHF2. Liver X receptors antagonize TLR4-dependent gene activation by maintaining NCoR/SMYD5-mediated repression. These findings reveal a histone H4K20 tri-methylation/de-methylation strategy that integrates positive and negative signaling inputs that control immunity and homeostasis. mRNA profiling from thioglycollate-elicited mouse macrophages treated with siRNA for Control, Smyd5 and Phf2 for 48 hours followed by 4 hours of LPS treatment.
Project description:Histone H3 lysine 9 methylation (H3K9me) is essential for cellular homeostasis; however, its contribution to development is not well established. Here, we demonstrate that the H3K9me2 demethylase PHF2 is essential for neural progenitor proliferation in vitro and for early neurogenesis in the chicken spinal cord. Using genome-wide analyses and biochemical assays we show that PHF2 controls the expression of critical cell cycle progression genes, particularly those related to DNA replication, by keeping low levels of H3K9me3 at promoters. Accordingly, PHF2 depletion induces R-loop accumulation that leads to extensive DNA damage and cell cycle arrest. These data reveal a role of PHF2 as a guarantor of genome stability that allows proper expansion of neural progenitors during development.
Project description:Histone H3 lysine 9 methylation (H3K9me) is essential for cellular homeostasis; however, its contribution to development is not well established. Here, we demonstrate that the H3K9me2 demethylase PHF2 is essential for neural progenitor proliferation in vitro and for early neurogenesis in the chicken spinal cord. Using genome-wide analyses and biochemical assays we show that PHF2 controls the expression of critical cell cycle progression genes, particularly those related to DNA replication, by keeping low levels of H3K9me3 at promoters. Accordingly, PHF2 depletion induces R-loop accumulation that leads to extensive DNA damage and cell cycle arrest. These data reveal a role of PHF2 as a guarantor of genome stability that allows proper expansion of neural progenitors during development.
Project description:SOX9 is a transcriptional activator required for chondrogenesis, and SOX5 and SOX6 are closely related DNA-binding proteins that critically enhance its function. We used RNA-seq to charatierize a rat chondrosarcoma (RCS) cells as a faithful model for proliferating/early prehypertrophic growth plate chondrocytes and ChIP-seq to gain novel insights into the full spectrum of the target genes and modes of action of this chondrogenic trio. ChIP-seq for SOX9, SOX6 and histone modifications were carried out using RCS cells
Project description:We find that treating mesenchymal NAMEC8 cells with cholera toxin (CTx) to elevate intracellular cAMP levels and activate PKA induces a mesenchymal-to-epithelial transition whereby the cells assume an epithelial state (N8-CTx). NAMEC8 cells undergo epigenetic reprogramming triggered by active PHF2, a histone demethylase, which demethylates H3K9me2 and H3K9me3 regions of epithelial genes silencing in the mesenchymal state
Project description:We find that treating mesenchymal NAMEC8 cells with cholera toxin (CTx) to elevate intracellular cAMP levels and activate PKA induces a mesenchymal-to-epithelial transition whereby the cells assume an epithelial state (N8-CTx). NAMEC8 cells undergo epigenetic reprogramming triggered by active PHF2, a histone demethylase, which demethylates H3K9me2 and H3K9me3 regions of epithelial genes silencing in the mesenchymal state
Project description:Sox9 is an SRY-related transcription factor required for expression of cartilaginous matrix genes in the developing skeletal system and heart valve structures. In contrast to positively regulating formation of cartilaginous matrix, Sox9 has also been shown to negatively regulate matrix mineralization associated with bone formation. While the transcriptional activation of Sox9 target genes during chondrogenesis has been well studied, the mechanisms by which Sox9 represses osteogenic processs are not so clear. To address this, we performed a genome-wide Sox9 ChIP-on-chip approach using neonatal mouse lim tissue. Chromatin immunoprecipitation was performed with pooled Sox9 antibodies and normal rabbit IgG as control using neonatal mouse limb tissue. Samples include Sox9 IP and IgG IP.
Project description:Heart valve formation initiates when endothelial cells of the heart transform into mesenchyme and populate the cardiac cushions. The transcription factor, SOX9, is highly expressed in the cardiac cushion mesenchyme, and is essential for heart valve development. Loss of Sox9 in mouse cardiac cushion mesenchyme alters cell proliferation, embryonic survival, and disrupts valve formation. Despite this important role, little is known regarding how SOX9 regulates heart valve formation or its transcriptional targets. Therefore, we mapped putative SOX9 binding sites by ChIP-Seq in embryonic day (E) 12.5 heart valves, a stage at which the valve mesenchyme is actively proliferating and initiating differentiation. Embryonic heart valves have been shown to express a high number of genes that are associated with chondrogenesis, including several extracellular matrix proteins and transcription factors that regulate chondrogenesis. Consequently, we compared regions of putative SOX9 DNA-binding between E12.5 heart valves and E12.5 limb buds. We identified context-dependent and contextâindependent SOX9 interacting regions throughout the genome. Analysis of context-independent SOX9 binding suggests an extensive role for SOX9 across tissues in regulating proliferation-associated genes including key components of the AP-1 complex. Integrative analysis of tissue-specific SOX9 interacting regions and gene expression profiles on Sox9-deficient heart valves demonstrated that SOX9 controls the expression of several transcription factors with previously identified roles in heart valve development, including Twist1, Sox4, Mecom/Evi1 and Pitx2. Together, our data identifies SOX9 coordinated transcriptional hierarchies that control cell proliferation and differentiation during valve formation. Examination of SOX9 binding sites in E12.5 atrioventricular canal (AVC) and E12.5 embryonic limb and mRNA expression profiling in E12.5 WT and Sox9 mutant AVCs, in duplicate.
Project description:To define the repertoire of Sox9-dependent genes that contribute to the regulation of chondrogenesis, we generated Sox9-3'enhanced green fluorescent protein (EGFP) knock-in mice (Sox9-3'EGFP) and Sox9-EGFP/EGFP null chimeras. EGFP-positive cells of Sox9-3'EGFP knock-in and Sox9-EGFP/EGFP null chimeric embryos harvested from limb buds at embryonic day 12.5 were sorted using a FACSAria flow cytometer (Becton-Dickinson). Total RNA of sorted cells was extracted using the RNeasy Mini Kit (QIAGEN) and amplified according to the instructions provided by Affymetrix. Microarray analysis using the Affymetrix Mouse Genome 430 2.0 Array was performed according to the manufacturer's instructions.