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:Heterochromatin stability is crucial for progenitor proliferation during early neurogenesis. It relays on the maintenance of local hubs of H3K9me. However, the current understanding of the processes involved in the formation of efficient localized levels of H3K9me remains limited. To address this intriguing question, we used a neural stem cell (NSC) to analyze the function of the H3K9me2 demethylase PHF2, which is crucial for progenitor proliferation. Through mass spectroscopy and genome-wide assays, we uncovered that PHF2 interacts with heterochromatin components and it is enriched at pericentromeric heterochromatin (PcH) boundaries. This binding is essential for maintaining silenced the satellite repeats thereby preventing DNA damage and genome instability. Depletion of PHF2 led to increased transcription of heterochromatic repeats, accompanied by a decrease in H3K9me3 levels and alterations in PcH organization. Further analysis revealed that PHF2's PHD and catalytic domains are crucial for maintaining PcH stability and preventing unscheduled repeat transcription, thereby safeguarding genome integrity. These results highlight the multifaceted nature of PHF2's functions in maintaining heterochromatin stability and regulating gene expression during neural development. Altogether, our study unravels the intricate relationship between heterochromatin stability and progenitor proliferation during mammalian neurogenesis, shedding light on its potential as a therapeutic target for neurodevelopmental disorders
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:Heterochromatin stability is crucial for progenitor proliferation during development. It relays on the maintenance of local hubs of H3K9me. However, the mechanisms underlying the establishment of competent local levels of H3K9me remain poorly understood. To address this intriguing question, we used a neural stem cell (NSC) model to analyze the significance of the H3K9me2 demethylase PHF2, which is crucial for progenitor proliferation. Through mass spectroscopy and genome-wide assays, we uncovered that PHF2 interacts with heterochromatin components and it is enriched at pericentromeric heterochromatin (PcH) boundaries. This binding is essential for maintaining silenced the satellite repeats and to prevent DNA damage and genome instability. To do that, PHF2 balances H3K9me3 levels at these boundaries to ensure high H3K9me3 levels at satellite repeats. Mechanistically, we discover that while its catalytic and PHD domains are indispensable, the intrinsically disordered region within PHF2 is dispensable for stabilizing PcH. Altogether, our study sheds light on the intricate relationship between heterochromatin stability and progenitor proliferation during mammalian neurogenesis.
Project description:Heterochromatin stability is crucial for progenitor proliferation during development. It relays on the maintenance of local hubs of H3K9me. However, the mechanisms underlying the establishment of competent local levels of H3K9me remain poorly understood. To address this intriguing question, we used a neural stem cell (NSC) model to analyze the significance of the H3K9me2 demethylase PHF2, which is crucial for progenitor proliferation. Through mass spectroscopy and genome-wide assays, we uncovered that PHF2 interacts with heterochromatin components and it is enriched at pericentromeric heterochromatin (PcH) boundaries. This binding is essential for maintaining silenced the satellite repeats and to prevent DNA damage and genome instability. To do that, PHF2 balances H3K9me3 levels at these boundaries to ensure high H3K9me3 levels at satellite repeats. Mechanistically, we discover that while its catalytic and PHD domains are indispensable, the intrinsically disordered region within PHF2 is dispensable for stabilizing PcH. Altogether, our study sheds light on the intricate relationship between heterochromatin stability and progenitor proliferation during mammalian neurogenesis.
Project description:Purpose: The aim of this study is (1) to identify the chromatin occupancy of the epigenetic regulator Setdb1 in mouse embryonic fibroblasts (MEF); (2) to profile key epigenetic marks H3K9me2, H3K9me3 and H3K27me3; utilizing wildtype cells with nonsilencing shRNA mediated knockdown and Setdb1 geneTrap heterozygous cells with Setdb1 shRNA mediated knockdown. Methods: Chromatin immunoprecipitation for Setdb1, H3K9me2, H3K9me3 and H3K27me3 was performed essentially as in (Nelson et al. 2006). Briefly, nuclei were isolated from formaldehyde crosslinked MEFs and chromatin was fragmented by sonication. Chromatin immunoprecipitation was performed with corresponding antibodies for Setdb1, H3K9me2, H3K9me3 and H3K27me3. DNA was extracted from the immunoprecipitated fraction following reverse-crosslinking. Isolated DNA was used to generate sequencing libraries with Illumina's TruSeq DNA Sample Preparation Kit according to manufacturer's instruction. Libraries were pooled and sequenced on the Illumina HiSeq 2000 platform for 100 bp single-end reads. Image analysis was performed in real time by the HiSeq Control Software (HCS) v1.4.8 and Real Time Analysis (RTA) v1.12.4.2, running on the instrument computer. Real-time base calling on the HiSeq instrument computer was performed with the RTA software. Illumina CASAVA1.8 pipeline was used to generate the sequence data. Chromatin occupancy of the epigenetic regulator Setdb1, H3K9me2, H3K9me3 and H3K27me3 in mouse embryonic fibroblasts (MEFs) with wildtype MEFs and nonsilencing shRNA mediated knockdown or Setdb1 geneTrap heterozygous MEFs with Setdb1 shRNA mediated knockdown was determined by Setdb1, H3K9me2, H3K9me3 and H3K27me3 ChIP-seq, respectively.