ABSTRACT: Dynamic analysis of gene expression and genome wide transcription factor binding during lineage-specification of multipotent progenitors [ER]
Project description:Dynamic analysis of gene expression and genome wide transcription factor binding during lineage-specification of multipotent progenitors
Project description:Dynamic analysis of gene expression and genome wide transcription factor binding during lineage-specification of multipotent progenitors [TC]
Project description:Dynamic analysis of gene expression and genome wide transcription factor binding during lineage-specification of multipotent progenitors [HP]
Project description:Dynamic analysis of gene expression and genome wide transcription factor binding during lineage-specification of multipotent progenitors [PC]
Project description:Dynamic analysis of gene expression and genome wide transcription factor binding during lineage-specification of multipotent progenitors [ChIP-seq].
Project description:Tcf1 is necessary for optimal T lineage development. Tcf1 deficient progenitors fail to initiate the T lineage program in vitro and development is severely defective in vivo. We used microarrays to assess the overal global gene expression differences from Tcf1 wildtype and deficient lymphoid biased progenitors cultures on Notch-ligand expressing stroma to determine if Tcf1 deficient progenitors are able to intiate the T lineage specification program. Abstract of manuscript: The thymus imposes the T cell fate on incoming multipotent progenitors, but the molecular mechanisms are poorly understood. We show that transcription factor Tcf1 initiates T-lineage-specific gene expression. Tcf1 is downstream of Notch1 signaling and expressed in early T-cell progenitors. Progenitors deficient for Tcf1 are unable to initiate normal T-lineage specification. Conversely, ectopic expression of Tcf1 in hematopoietic progenitors is sufficient to induce expression of T-lineage specific genes in vitro. Thus, our study identifies Tcf1 as critically involved in the establishment T cell identity. Tcf1 wildtype and deficient bone marrow lymphoid primed progenitors (LMPPs, Lineage marker- Sca+kit+Flt3high) were harvested in triplicate and seeded onto OP9-DL4 expressing stroma for 4 days upon which highly pure lineage negative and Thy1+CD25+ T cells were cell sorted for expression analysis. The lineage negative populations represent three seperate mice from each genotype and the Thy1+CD25+T lineage population represents two replicates from the Tcf1 wildtype group. No Thy1+CD25+ T lineage cells develop from Tcf1 deficient progentiors.
Project description:Tcf1 is necessary for optimal T lineage development. Tcf1 deficient progenitors fail to initiate the T lineage program in vitro and development is severely defective in vivo. We used microarrays to assess the overal global gene expression differences from Tcf1 wildtype and deficient lymphoid biased progenitors cultures on Notch-ligand expressing stroma to determine if Tcf1 deficient progenitors are able to intiate the T lineage specification program. Abstract of manuscript: The thymus imposes the T cell fate on incoming multipotent progenitors, but the molecular mechanisms are poorly understood. We show that transcription factor Tcf1 initiates T-lineage-specific gene expression. Tcf1 is downstream of Notch1 signaling and expressed in early T-cell progenitors. Progenitors deficient for Tcf1 are unable to initiate normal T-lineage specification. Conversely, ectopic expression of Tcf1 in hematopoietic progenitors is sufficient to induce expression of T-lineage specific genes in vitro. Thus, our study identifies Tcf1 as critically involved in the establishment T cell identity.
Project description:B-lymphocyte development is dependent on the interplay between the chromatin landscape and lineage specific transcription factors. It has been suggested that B-lineage commitment is associated with major changes in the nuclear chromatin environment proposing a critical role for lineage specific transcription factors in the formation of the epigenetic landscape. In this report we have used chromosome conformation capture in combination with ATAC-seq analysis to enable highly efficient annotation of both proximal and distal transcriptional control elements to genes activated in B-lineage specification. A large majority of these genes were annotated to at least one regulatory element with an accessible chromatin configuration in multipotent progenitors. Furthermore, the majority of binding sites for the key regulators of B-lineage specification, EBF1 and PAX5, occurred in already accessible regions. EBF1 did, however, cause a dynamic change in ATAC-accessibility and was critical for an increase in distal promoter-enhancer interactions as well as high deposition of chromatin modulating co-factors associated with the establishment of the B-lineage program. Our data unravel an unappreciated level of epigenetic priming at regulatory elements annotated to lineage restricted genes and provide insight into the mechanisms by which lineage specific transcription factors act via already accessible elements in lineage specification.
Project description:We used microarrays to perform a global gene expression analysis in Tcf1-expressing Thy1+CD25+ T lineage cells that develop on OP9 stroma in the absence of Notch1 signals. We compare this to the starting population, LMPP progenitors, and to control expressing T lineage cells that developed on OP9 stroma expressing Notch ligand DL4. The overall goal of this study was to determine if Tcf1 initiates T lineage specification in lymphoid progenitors. We found that Tcf1 was sufficient to upregulate many T lineage genes as compared to control expressing progenitors on OP9-DL4. Abstract of manuscript: The thymus imposes the T cell fate on incoming multipotent progenitors, but the molecular mechanisms are poorly understood. We show that transcription factor Tcf1 initiates T-lineage-specific gene expression. Tcf1 is downstream of Notch1 signaling and expressed in early T-cell progenitors. Progenitors deficient for Tcf1 are unable to initiate normal T-lineage specification. Conversely, ectopic expression of Tcf1 in hematopoietic progenitors is sufficient to induce expression of T-lineage specific genes in vitro. Thus, our study identifies Tcf1 as critically involved in the establishment T cell identity. Wiltype LMPPs were isolated by a FACSAria cell sorter and retrovirally transduced with a Tcf1-containing (Tcf1-VEX) or control vector (VEX) retrovirus. Tcf1-expressing cells and control-vector expressing cells were then seeded on OP9 stroma or OP9 stroma expressing Notch ligand DL4, respectively. On day 10, Thy1+CD25+ T lineage cells were sorted from Tcf1-expressing cells on OP9 stroma and compared to sorted LMPPs and Thy1+CD25+ T lineage cells that developed from control-vector expressing cells on OP9-DL4.
Project description:Dynamic gene expression programs determine multipotent cell states and fate choices during development. Multipotent progenitors for cardiomyocytes and branchiomeric head muscles populate the pharyngeal mesoderm of vertebrate embryos, but the mechanisms underlying cardiopharyngeal multipotency and heart vs. head muscle fate choices remain elusive. The tunicate Ciona emerged as a simple chordate model to study cardiopharyngeal development with unprecedented spatio-temporal resolution. We analyzed the transcriptome of single cardiopharyngeal lineage cells isolated at successive time points encompassing the transitions from multipotent progenitors to distinct first and second heart, and pharyngeal muscle precursors. We reconstructed the three cardiopharyngeal developmental trajectories, and characterized gene expression dynamics and regulatory states underlying each fate choice. Experimental perturbations and bulk transcriptome analyses revealed that ongoing FGF/MAPK signaling maintains cardiopharyngeal multipotency and promotes the pharyngeal muscle fate, whereas signal termination permits the deployment of a full pan-cardiac program and heart fate specification. We identified the Dach1/2 homolog as a novel evolutionarily conserved second-heart-field-specific factor and demonstrate, through lineage tracing and CRISPR/Cas9 perturbations, that it operates downstream of Tbx1/10 to actively suppress the first heart lineage program. This data indicates that the regulatory state of multipotent cardiopharyngeal progenitors determines the first vs. second heart lineage choice, and that Tbx1/10 acts as a bona fide regulator of cardiopharyngeal multi potency. We performed bulk RNAseq to profile the FACS purified Ciona Robusta Truck Ventral Cells (TVCs) with FGF-MAPK perturbation conditions to address the question- What is the role of FGF signaling pathway during early cardiopharyngeal specification. we performed bulk RNA sequencing of FACS-purified cardiopharyngeal lineage cells isolated from embryos and larvae expressing either a dominant negative form the fibroblast growth factor receptor (dnFGFR), or a constitutively active form of M-Ras (caM-Ras), the sole Ras homolog in Ciona, under the control of TVC-specific enhancers.