Project description:DNA methylation changes dynamically during development and is essential for embryogenesis in mammals. However, how DNA methylation affects developmental gene expression and cell differentiation remains elusive. During embryogenesis, many key transcription factors are used repeatedly, triggering different outcomes depending on the cell type and developmental stage. Here, we report that DNA methylation modulates transcription-factor output in the context of cell differentiation. Using a drug-inducible Gata4 system and a mouse embryonic stem (ES) cell model of mesoderm differentiation, we examined the cellular response to Gata4 in ES and mesoderm cells. The activation of Gata4 in ES cells is known to drive their differentiation to endoderm. We show that the differentiation of wild-type ES cells into mesoderm blocks their Gata4-induced endoderm differentiation, while mesoderm cells derived from ES cells that are deficient in the DNA methyltransferases Dnmt3a and Dnmt3b can retain their response to Gata4, allowing lineage conversion from mesoderm cells to endoderm in part. Transcriptome analysis of the cells' response to Gata4 over time revealed groups of endoderm and mesoderm developmental genes whose expression was induced by Gata4 only when DNA methylation was lost, suggesting that DNA methylation restricts the ability of these genes to respond to Gata4, rather than controlling their transcription per se. Our data indicate that epigenetic regulation by DNA methylation functions as a heritable safeguard to prevent transcription factors from activating inappropriate downstream genes, thereby contributing to the restriction of the differentiation potential of somatic cells. To understand how mouse cells differentially respond to Gata4 in cell type- and DNA methylation-dependent manners and to examine what genes are differentially regulated, we analyzed temporal change of gene expression profile in response to Gata4 in ES or Flk1(+) mesoderm cells in WT and Dnmt3a-/-Dnmt3b-/- (DKO) background, in total 108 samples.
Project description:DNA methylation changes dynamically during development and is essential for embryogenesis in mammals. However, how DNA methylation affects developmental gene expression and cell differentiation remains elusive. During embryogenesis, many key transcription factors are used repeatedly, triggering different outcomes depending on the cell type and developmental stage. Here, we report that DNA methylation modulates transcription-factor output in the context of cell differentiation. Using a drug-inducible Gata4 system and a mouse embryonic stem (ES) cell model of mesoderm differentiation, we examined the cellular response to Gata4 in ES and mesoderm cells. The activation of Gata4 in ES cells is known to drive their differentiation to endoderm. We show that the differentiation of wild-type ES cells into mesoderm blocks their Gata4-induced endoderm differentiation, while mesoderm cells derived from ES cells that are deficient in the DNA methyltransferases Dnmt3a and Dnmt3b can retain their response to Gata4, allowing lineage conversion from mesoderm cells to endoderm in part. Transcriptome analysis of the cells' response to Gata4 over time revealed groups of endoderm and mesoderm developmental genes whose expression was induced by Gata4 only when DNA methylation was lost, suggesting that DNA methylation restricts the ability of these genes to respond to Gata4, rather than controlling their transcription per se. Our data indicate that epigenetic regulation by DNA methylation functions as a heritable safeguard to prevent transcription factors from activating inappropriate downstream genes, thereby contributing to the restriction of the differentiation potential of somatic cells.
Project description:Pluripotent stem cells provide a powerful system to dissect the underlying molecular dynamics that regulate cell fate changes during mammalian development. Here we report the integrative analysis of genome wide binding data for 38 transcription factors with extensive epigenome and transcriptional data across the differentiation of human embryonic stem cells to the three germ layers. We describe core regulatory dynamics and show the lineage specific behavior of selected factors. In addition to the orchestrated remodeling of the chromatin landscape, we find that the binding of several transcription factors is strongly associated with specific loss of DNA methylation in one germ layer and in many cases a reciprocal gain in the other layers. Taken together, our work shows context-dependent rewiring of transcription factor binding, downstream signaling effectors, and the epigenome during human embryonic stem cell differentiation. 200 ChIP-seq experiments profiling 38 transcription factors (TFs) and several chromatin marks in 5 cell types--male human ES cell line HUES64 and directed differentiation of HUES64 towards mesendoderm (dMS, 12 hours), endoderm (dEN, 120 hours), mesoderm (dME, 120 hours), and ectoderm (dEC, 120 hours). In addition, three ES cell lines were derived with shRNA mediated knockdown of GATA4 and differention toward endoderm (dEN_shGATA4) and mesoderm (dME_shGATA4). These cell lines were used for MNChIP-seq of GATA4, SMAD1, and H3K27Ac and for 4 RRBS experiments in GATA4 knockdown and control cell lines.
Project description:The integration of cell metabolism with signalling pathways, transcription factor networks and epigenetic mediators is critical in coordinating molecular and cellular events during embryogenesis. Induced pluripotent stem cells (IPSCs) are an established model for embryogenesis, germ layer specification and cell lineage differentiation, advancing the study of human embryonic development and the translation of innovations in drug discovery, disease modelling and cell-based therapies. The metabolic regulation of IPSC pluripotency is mediated by balancing glycolysis and oxidative phosphorylation, but there is a paucity of data regarding the influence of individual metabolite changes during cell lineage differentiation. We used <sup>1</sup>H NMR metabolite fingerprinting and footprinting to monitor metabolite levels as IPSCs are directed in a three-stage protocol through primitive streak/mesendoderm, mesoderm and chondrogenic populations. Metabolite changes were associated with central metabolism, with aerobic glycolysis predominant in IPSC, elevated oxidative phosphorylation during differentiation and fatty acid oxidation and ketone body use in chondrogenic cells. Metabolites were also implicated in the epigenetic regulation of pluripotency, cell signalling and biosynthetic pathways. Our results show that <sup>1</sup>H NMR metabolomics is an effective tool for monitoring metabolite changes during the differentiation of pluripotent cells with implications on optimising media and environmental parameters for the study of embryogenesis and translational applications.
Project description:Cellular differentiation involves widespread epigenetic reprogramming, including modulation of DNA methylation patterns. We have investigated DNA genome-wide methylation dynamics in embryonic stem cells, primary myoblasts, terminal differentiated myotubes and mature myofibers. About 1.000 differentially methylated regions (DMRs) have been indentified during muscle-lineage determination and terminal differentiation. As a whole, muscle lineage commitment was characterized by a major gain of DNA methylation, while muscle differentiation was accompanied by loss of DNA methylation in CpG-poor regions. Notably, hypomethylated regions in muscle cells were neighboured by enhancer-type chromatin, suggesting the involvement of DNA methylation in the regulation of cell-type specific enhancers. Indeed, one of the hypomethylations detected in muscle cells affected the super-enhancer of the master transcription factor Myf5. Super-enhancers have been defined as large clusters of transcriptional enhancers driving cell-identity and gene expression, but how these lineage-specific super-enhancers are specifically activated or repressed in different tissues is not well understood. We demonstrated that the binding of the transcription factor USF1 to Myf5 locus occurs upon DNA demethylation of the super-enhancer region in myogenic committed cells. Taken all together, we have characterized the unique DNA methylation signatures of muscle-committed cells and highlighted the importance of DNA methylation mediated regulation of cell identity super-enhancers. We have investigated DNA genome-wide methylation dynamics in embryonic stem cells, primary myoblasts, terminal differentiated myotubes and mature myofibers by AIMS-seq techniques and coupled to microarray expression data by SurePrint G3 Mouse 8x60K from Agilent Technologies. Samples were in triplicates, except for ESCs (quadruplicates).
Project description:The second heart field (SHF) comprises a population of mesodermal progenitor cells that are added to the nascent linear heart to give rise to the majority of the right ventricle, interventricular septum, and outflow tract of mammals and birds. The zinc finger transcription factor GATA4 functions as an integral member of the cardiac transcription factor network in the SHF and its derivatives. In addition to its role in cardiac differentiation, GATA4 is also required for cardiomyocyte replication, although the transcriptional targets of GATA4 required for proliferation have not been previously identified. In the present study, we disrupted Gata4 function exclusively in the SHF and its derivatives. Gata4 SHF knockout mice die by embryonic day 13.5 and exhibit hypoplasia of the right ventricular myocardium and interventricular septum and display profound ventricular septal defects. Loss of Gata4 function in the SHF results in decreased myocyte proliferation in the right ventricle, and we identify numerous cell cycle genes that are dependent on Gata4 by microarray analysis. We show that Gata4 is required for Cyclin D2 expression in the right ventricle and that the Cyclin D2 promoter is bound and activated by GATA4 via three consensus GATA binding sites. These findings establish Cyclin D2 as a direct transcriptional target of GATA4 and support a model in which GATA4 controls cardiomyocyte proliferation by coordinately regulating numerous cell cycle genes. Experiment Overall Design: Onewat ANOVA with post-hoc was done with 3 genotypes with replicates. Three genetypes are Gata4flox/+; Nkx2-5+/+ (control, n=3), Gata4flox/+; Nkx2-5Cre/+ (Gata4; Nkx2-5 double heterozygous, Experiment Overall Design: 170 n=3), and Gata4flox/flox; Nkx2-5Cre/+ (Gata4 CKONkx, n=5).
Project description:ZNF462 haploinsufficiency is linked to Weiss-Kruszka Syndrome, a genetic disorder characterized by neurodevelopmental defects including Autism. Though conserved in vertebrates and essential for embryonic development the molecular functions of ZNF462 remain unclear. We identified its murine homolog ZFP462 in a screen for mediators of epigenetic gene silencing. Here, we show that ZFP462 safeguards neural lineage specification of mouse embryonic stem cells (ESCs) by targeting the H3K9-specific histone methyltransferase complex G9A/GLP to silence mesoendodermal genes. ZFP462 binds to transposable elements (TEs) that are potential enhancers harboring ESC-specific transcription factor (TF) binding sites. Recruiting G9A/GLP, ZFP462 seeds heterochromatin, restricting TF binding. Loss of ZFP462 in ESCs results in increased chromatin accessibility at target sites and ectopic expression of mesoendodermal genes. Taken together, ZFP462 confers lineage- and locus-specificity to the broadly expressed epigenetic regulator G9A/GLP. Our results suggest that aberrant activation of lineage non-specific genes in the neuronal lineage underlies ZNF462-associated neurodevelopmental pathology.
Project description:Specification of the mesodermal lineages requires a complex set of morphogenetic events orchestrated by interconnected signaling pathways and gene regulatory networks. The transcription factor Sox7 has critical functions in differentiation of multiple mesodermal lineages, including cardiac, endothelial, and hematopoietic. Using a doxycycline-inducible mouse embryonic stem cell (mESC) line, we have previously shown that expression of Sox7 in cardiovascular progenitor cells promotes expansion of endothelial progenitor cells. Here, we show that the ability of Sox7 to promote endothelial cell fate occurs at the expense of the cardiac lineage. Using ChIP-Seq coupled with ATAC-Seq we identify downstream target genes of Sox7 in cardiovascular progenitor cells and, by integrating these data with transcriptomic analyses, we define Sox7-dependent gene programs specific to cardiac and endothelial progenitor cells. Further, we demonstrate a protein-protein interaction between SOX7 and GATA4 and provide evidence that Sox7 interferes with the transcriptional activity of Gata4 on cardiac genes. In addition, we show Sox7 modulates WNT and BMP signaling during cardiovascular differentiation. Our data represent the first genome-wide analysis of Sox7 function and reveal a critical role for Sox7 in regulating signaling pathways that affect cardiovascular progenitor cell differentiation.
Project description:During embryogenesis, many key transcription factors are used repeatedly, achieving different outcomes depending on cell type and developmental stage. The epigenetic modification of the genome functions as a memory of a cell’s developmental history, and it has been proposed that such modification shapes the cellular response to transcription factors. To investigate the role of DNA methylation in the response to transcription factor Gata4, we have tried to identify GATA4-binding associated genes of WT-type and Dnmt3a-/-Dnmt3b-/-(DKO) in Flk1-based mesoderm progenitor by Gata4 ChIP-analysis.