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: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: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.
Project description:Cellular binary fate decisions require the progeny to silence genes associated with the alternative fate. The major subsets of alpha:beta T cells have been extensively studied as a model system for fate decisions. While the transcription factor RUNX3 is required for the initiation of Cd4 silencing in CD8 T cell progenitors, it is not required to maintain the silencing of Cd4 and other helper T lineage genes. The other runt domain containing protein, RUNX1, silences Cd4 in an earlier T cell progenitor, but this silencing is reversed whereas the gene silencing after RUNX3 expression is not reverse. Therefore, we hypothesized that RUNX3 and not RUNX1 recruits other factors that maintains the silencing of helper T lineage genes in CD8 T cells. To this end, we performed a proteomics screen of RUNX1 and RUNX3 to determine candidate silencing factors.
Project description:Expression data from Tcf1 deficient and Tcf1 wildtype cultured bone marrow lymphoid primed progenitors after four days on Notch ligand expressing stroma (OP9-DL4).
Project description:We collected whole genome testis expression data from hybrid zone mice. We integrated GWAS mapping of testis expression traits and low testis weight to gain insight into the genetic basis of hybrid male sterility.