Project description:Purpose: we aimed to gain a genome-wide view of the dynamics in DNA methylation inheritance and define the factors associated with methylation fidelity. Methods: Using mouse embryonic stem cell (ES-E14TG2a) in both undifferentiated and differentiated states as a model system, we exploited the hairpin bisulfite sequencing approach to generate methylation data for DNA double strands simultaneously at single-base resolution. We generated the genome-wide hairpin bisulfite sequencing data to capture the methylation pattern variation during the stem cell transition from self-renewal to commitment, and integrated with various M-bM-^@M-^\omicsM-bM-^@M-^] data to scrutinize the relationships among DNA methylation inheritance, gene expression, histone modification, transcriptional factor binding and distribution of 5-hydroxylmethylation cytosine. Results and conclusion: Our results indicated that DNA methylation fidelity increases globally during early mouse embryonic stem cell differentiation. Methylation fidelity is remarkably high in promoter regions of actively expressed genes and positively correlated with active histone modification marks and binding of transcriptional factors. Strikingly, methylation fidelity follows a bimodal distribution for the intermediately methylated CpG dyads. In addition, the methylation difference in between two DNA strands rather than different DNA molecules is a major source of the intermediate DNA methylation. Lastly, while 5-hmC and 5-mC tend to coexist, no significant increase in the pairing with unmethylated cytosine was observed. For mouse embryonic stem cell of undifferentiated and spontaneous differentiated states, we determined DNA double strands methylation pattern by hairpin bisulfite sequencing approach and determined gene expression profiles using RNA-seq.
Project description:Purpose: we aimed to gain a genome-wide view of the dynamics in DNA methylation inheritance and define the factors associated with methylation fidelity. Methods: Using mouse embryonic stem cell (ES-E14TG2a) in both undifferentiated and differentiated states as a model system, we exploited the hairpin bisulfite sequencing approach to generate methylation data for DNA double strands simultaneously at single-base resolution. We generated the genome-wide hairpin bisulfite sequencing data to capture the methylation pattern variation during the stem cell transition from self-renewal to commitment, and integrated with various “omics” data to scrutinize the relationships among DNA methylation inheritance, gene expression, histone modification, transcriptional factor binding and distribution of 5-hydroxylmethylation cytosine. Results and conclusion: Our results indicated that DNA methylation fidelity increases globally during early mouse embryonic stem cell differentiation. Methylation fidelity is remarkably high in promoter regions of actively expressed genes and positively correlated with active histone modification marks and binding of transcriptional factors. Strikingly, methylation fidelity follows a bimodal distribution for the intermediately methylated CpG dyads. In addition, the methylation difference in between two DNA strands rather than different DNA molecules is a major source of the intermediate DNA methylation. Lastly, while 5-hmC and 5-mC tend to coexist, no significant increase in the pairing with unmethylated cytosine was observed.
Project description:Cell cycle progression is linked to transcriptome dynamics and variations in the response of pluripotent cells to differentiation cues, through mostly unknown determinants. Here, we characterized the cell cycle–associated transcriptome and proteome of mouse embryonic stem cells (mESCs) in naïve ground state. We found that the thymine DNA glycosylase (TDG) is a cell cycle–regulated co-factor of the tumour suppressor p53. Further, TDG and p53 co-bind ESC-specific cis-regulatory elements and thereby control transcription of p53-dependent genes during self-renewal. We determined that the dynamic expression of TDG is required to promote the cell cycle–associated transcriptional heterogeneity. Moreover, we demonstrated that transient depletion of TDG influences cell fate decisions during the early differentiation of mESCs. Our findings reveal an unanticipated role of TDG in promoting molecular heterogeneity during the cell cycle, and highlight the central role of protein dynamics for the temporal control of cell fate during development.
Project description:The Nucleosome Remodeling and Deacetylase (NuRD) complex plays an important role in gene expression regulation, stem cell self-renewal, and lineage commitment. Yet little is known about the dynamics of NuRD during cellular differentiation. Here, we study these dynamics using genome-wide profiling and quantitative interaction proteomics in mouse embryonic stem cells (ESCs) and neural progenitor cells (NPCs). The genomic targets of NuRD are highly dynamic during differentiation, with most binding occurring at cell-type specific promoters and enhancers. We identify ZFP296 as a novel, ESC-specific NuRD interactor that also interacts with the SIN3A complex. ChIP-sequencing in Zfp296 knockout (KO) ESCs reveals decreased NuRD binding both genome-wide and at ZFP296 binding sites, although this has little effect on the transcriptome. Nevertheless, Zfp296 KO ESCs exhibit delayed induction of lineage-specific markers upon differentiation to embryoid bodies. In summary, we identify an ESC-specific NuRD interacting protein which regulates genome-wide NuRD binding and cellular differentiation.
Project description:During in vitro differentiation, pluripotent stem cells undergo extensive remodeling of their gene expression profiles. While studied extensively at the transcriptome level, much less is known about protein dynamics, which might differ significantly from their mRNA counterparts. Here, we present deep proteome-wide measurements of protein levels during the differentiation of embryonic stem cells.
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:Chickarmane2006 - Stem cell switch reversible
Kinetic modeling approach of the transcriptional dynamics of the embryonic stem cell switch.
This model is described in the article:
Transcriptional dynamics of the embryonic stem cell switch.
Chickarmane V, Troein C, Nuber UA, Sauro HM, Peterson C
PLoS Computational Biology. 2006; 2(9):e123
Abstract:
Recent ChIP experiments of human and mouse embryonic stem cells have elucidated the architecture of the transcriptional regulatory circuitry responsible for cell determination, which involves the transcription factors OCT4, SOX2, and NANOG. In addition to regulating each other through feedback loops, these genes also regulate downstream target genes involved in the maintenance and differentiation of embryonic stem cells. A search for the OCT4-SOX2-NANOG network motif in other species reveals that it is unique to mammals. With a kinetic modeling approach, we ascribe function to the observed OCT4-SOX2-NANOG network by making plausible assumptions about the interactions between the transcription factors at the gene promoter binding sites and RNA polymerase (RNAP), at each of the three genes as well as at the target genes. We identify a bistable switch in the network, which arises due to several positive feedback loops, and is switched on/off by input environmental signals. The switch stabilizes the expression levels of the three genes, and through their regulatory roles on the downstream target genes, leads to a binary decision: when OCT4, SOX2, and NANOG are expressed and the switch is on, the self-renewal genes are on and the differentiation genes are off. The opposite holds when the switch is off. The model is extremely robust to parameter changes. In addition to providing a self-consistent picture of the transcriptional circuit, the model generates several predictions. Increasing the binding strength of NANOG to OCT4 and SOX2, or increasing its basal transcriptional rate, leads to an irreversible bistable switch: the switch remains on even when the activating signal is removed. Hence, the stem cell can be manipulated to be self-renewing without the requirement of input signals. We also suggest tests that could discriminate between a variety of feedforward regulation architectures of the target genes by OCT4, SOX2, and NANOG.
This model is hosted on BioModels Database
and identified by: MODEL7957907314
.
To cite BioModels Database, please use: BioModels Database: An enhanced, curated and annotated resource for published quantitative kinetic models
.
To the extent possible under law, all copyright and related or neighbouring rights to this encoded model have been dedicated to the public domain worldwide. Please refer to CC0 Public Domain Dedication
for more information.
Project description:Chickarmane2006 - Stem cell switch irreversible
Kinetic modeling approach of the transcriptional dynamics of the embryonic stem cell switch.
This model is described in the article:
Transcriptional dynamics of the embryonic stem cell switch.
Chickarmane V, Troein C, Nuber UA, Sauro HM, Peterson C
PLoS Computational Biology. 2006; 2(9):e123
Abstract:
Recent ChIP experiments of human and mouse embryonic stem cells have elucidated the architecture of the transcriptional regulatory circuitry responsible for cell determination, which involves the transcription factors OCT4, SOX2, and NANOG. In addition to regulating each other through feedback loops, these genes also regulate downstream target genes involved in the maintenance and differentiation of embryonic stem cells. A search for the OCT4-SOX2-NANOG network motif in other species reveals that it is unique to mammals. With a kinetic modeling approach, we ascribe function to the observed OCT4-SOX2-NANOG network by making plausible assumptions about the interactions between the transcription factors at the gene promoter binding sites and RNA polymerase (RNAP), at each of the three genes as well as at the target genes. We identify a bistable switch in the network, which arises due to several positive feedback loops, and is switched on/off by input environmental signals. The switch stabilizes the expression levels of the three genes, and through their regulatory roles on the downstream target genes, leads to a binary decision: when OCT4, SOX2, and NANOG are expressed and the switch is on, the self-renewal genes are on and the differentiation genes are off. The opposite holds when the switch is off. The model is extremely robust to parameter changes. In addition to providing a self-consistent picture of the transcriptional circuit, the model generates several predictions. Increasing the binding strength of NANOG to OCT4 and SOX2, or increasing its basal transcriptional rate, leads to an irreversible bistable switch: the switch remains on even when the activating signal is removed. Hence, the stem cell can be manipulated to be self-renewing without the requirement of input signals. We also suggest tests that could discriminate between a variety of feedforward regulation architectures of the target genes by OCT4, SOX2, and NANOG.
This model is hosted on BioModels Database
and identified by: MODEL7957942740
.
To cite BioModels Database, please use: BioModels Database: An enhanced, curated and annotated resource for published quantitative kinetic models
.
To the extent possible under law, all copyright and related or neighbouring rights to this encoded model have been dedicated to the public domain worldwide. Please refer to CC0 Public Domain Dedication
for more information.
Project description:Cytosine methylation is an epigenetic mark usually associated with gene repression. Despite a requirement for de novo DNA methylation for differentiation of embryonic stem cells, its role in somatic stem cells is unknown. Using conditional ablation, we show that loss of either, or both, Dnmt3a or Dnmt3b, progressively impedes hematopoietic stem cell (HSC) differentiation during serial in vivo passage. Concomitantly, HSC self-renewal is immensely augmented in absence of either Dnmt3, particularly Dnmt3a. Dnmt3-KO HSCs show upregulation of HSC multipotency genes and downregulation of early differentiation factors, and the differentiated progeny of Dnmt3-KO HSCs exhibit hypomethylation and incomplete repression of HSC-specific genes. HSCs lacking Dnmt3a manifest hyper-methylation of CpG islands and hypo-methylation of genes which are highly correlated with human hematologic malignancies. These data establish that aberrant DNA methylation has direct pathologic consequences for somatic stem cell development, leading to inefficient differentiation and maintenance of a self-renewal program. Reduced representation bisulfite sequencing (MspI,~40-220bp size fraction) of secondarily-transplanted wild-type and Dnmt3a conditional knockout hematopoietic stem cells. We used microarrays to detail the global expression of genes in secondarily-transplanted control-HSCs and Dnmt3a-KO-HSCs.
Project description:While the core subunits of Polycomb group (PcG) complexes are well characterized, little is known about the dynamics of these protein complexes during cellular differentiation. We used quantitative interaction proteomics to study PcG proteins in mouse embryonic stem cells (mESCs) and neural progenitor cells (NPCs). We found the stoichiometry of PRC1 and PRC2 to be highly dynamic during neural differentiation.