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:Cell fate decisions during hematopoiesis are governed by lineage-specific transcription factors, such as RUNX1, SCL/TAL1, FLI1 and C/EBP family members. In order to gain insight about how these transcription factors regulate the activation of hematopoietic genes during embryonic development, we measured the genome-wide dynamics of transcription factor assembly on their target genes during the RUNX1-dependent transition from hemogenic endothelium to hematopoietic progenitors. Using a RUNX1-/- embryonic stem cell differentiation model expressing an inducible RUNX1 gene, we show that in the absence of RUNX1, SCL/TAL1, FLI1 and C/EBP-beta prime hematopoietic genes and that this early priming is required for correct temporal expression of the myeloid master regulator PU.1 and its downstream targets. After induction, RUNX1 binds to numerous new sites, initiating a local increase of histone acetylation and rapid global alterations in the binding patterns of SCL/TAL1 and FLI1. The acquisition of hematopoietic fate controlled by RUNX1 therefore does not represent the establishment of a new regulatory layer on top of a pre-existing hemogenic endothelium program but instead entails global reorganization of lineage-specific transcription factor assemblies. Microarray expression data obtained from differentiating murine hematopoietic cells, 3 independent biological replicates (measured twice) from iRUNX1 culture -/+DOX induction
Project description:Cell fate decisions during hematopoiesis are governed by lineage-specific transcription factors, such as RUNX1, SCL/TAL1, FLI1 and C/EBP family members. In order to gain insight about how these transcription factors regulate the activation of hematopoietic genes during embryonic development, we measured the genome-wide dynamics of transcription factor assembly on their target genes during the RUNX1-dependent transition from hemogenic endothelium to hematopoietic progenitors. Using a RUNX1-/- embryonic stem cell differentiation model expressing an inducible RUNX1 gene, we show that in the absence of RUNX1, SCL/TAL1, FLI1 and C/EBPM-NM-2 prime hematopoietic genes and that this early priming is required for correct temporal expression of the myeloid master regulator PU.1 and its downstream targets. After induction, RUNX1 binds to numerous new sites, initiating a local increase of histone acetylation and rapid global alterations in the binding patterns of SCL/TAL1 and FLI1. The acquisition of hematopoietic fate controlled by RUNX1 therefore does not represent the establishment of a new regulatory layer on top of a pre-existing hemogenic endothelium program but instead entails global reorganization of lineage-specific transcription factor assemblies. ChIPseq data from transcription factors Runx1, Fli-1, Scl/Tal1 and C/EBPM-NM-2, histone modification H3K9Ac as well as RNA Pol II obtained from differentiating murine hematopoietic cells
Project description:Cell fate decisions during hematopoiesis are governed by lineage-specific transcription factors, such as RUNX1, SCL/TAL1, FLI1 and C/EBP family members. In order to gain insight about how these transcription factors regulate the activation of hematopoietic genes during embryonic development, we measured the genome-wide dynamics of transcription factor assembly on their target genes during the RUNX1-dependent transition from hemogenic endothelium to hematopoietic progenitors. Using a RUNX1-/- embryonic stem cell differentiation model expressing an inducible RUNX1 gene, we show that in the absence of RUNX1, SCL/TAL1, FLI1 and C/EBP-beta prime hematopoietic genes and that this early priming is required for correct temporal expression of the myeloid master regulator PU.1 and its downstream targets. After induction, RUNX1 binds to numerous new sites, initiating a local increase of histone acetylation and rapid global alterations in the binding patterns of SCL/TAL1 and FLI1. The acquisition of hematopoietic fate controlled by RUNX1 therefore does not represent the establishment of a new regulatory layer on top of a pre-existing hemogenic endothelium program but instead entails global reorganization of lineage-specific transcription factor assemblies.
Project description:Cell fate decisions during hematopoiesis are governed by lineage-specific transcription factors, such as RUNX1, SCL/TAL1, FLI1 and C/EBP family members. In order to gain insight about how these transcription factors regulate the activation of hematopoietic genes during embryonic development, we measured the genome-wide dynamics of transcription factor assembly on their target genes during the RUNX1-dependent transition from hemogenic endothelium to hematopoietic progenitors. Using a RUNX1-/- embryonic stem cell differentiation model expressing an inducible RUNX1 gene, we show that in the absence of RUNX1, SCL/TAL1, FLI1 and C/EBPβ prime hematopoietic genes and that this early priming is required for correct temporal expression of the myeloid master regulator PU.1 and its downstream targets. After induction, RUNX1 binds to numerous new sites, initiating a local increase of histone acetylation and rapid global alterations in the binding patterns of SCL/TAL1 and FLI1. The acquisition of hematopoietic fate controlled by RUNX1 therefore does not represent the establishment of a new regulatory layer on top of a pre-existing hemogenic endothelium program but instead entails global reorganization of lineage-specific transcription factor assemblies.
Project description:The t(12;21) chromosomal translocation, targeting the gene encoding the RUNX1 transcription factor, is observed in 25% of pediatric acute lymphoblastic leukemia (ALL) and is an initiating event in the disease. To elucidate the mechanism by which RUNX1 disruption initiates leukemogenesis, we investigated its normal role in murine B-cell development. Gene expression analysis and genome-wide Runx1-occupancy studies support the hypothesis that Runx1 reinforces the transcription factor network in B-cell progenitors governing early B-cell survival and development . ChIP-seq experiments were performed in the proB-cell line BMiFLT3(15-3), stably transduced with the transcription factor Runx1, to identify Runx1-bound sites in early B-cell progenitors.
Project description:The t(12;21) chromosomal translocation, targeting the gene encoding the RUNX1 transcription factor, is observed in 25% of pediatric acute lymphoblastic leukemia (ALL) and is an initiating event in the disease. To elucidate the mechanism by which RUNX1 disruption initiates leukemogenesis, we investigated its normal role in murine B-cell development. Gene expression analysis and genome-wide Runx1-occupancy studies support the hypothesis that Runx1 reinforces the transcription factor network in B-cell progenitors governing early B-cell survival and development . 1) To identify Runx1 target genes in early B-cell progenitors, we used a whole genome microarray for analyzing the gene expression profile in a proB-cell line [BMiFLT3(15-3)] engineered to overexpresses the Runx1 transcription factor fused to the ligand binding domain of the estrogen receptor. The use of an inducible Runx1 fusion protein allowed specific translocation of Runx1 into the nucleus activation of Runx1 target genes. 2) To identify Runx1 target genes in early B-cell progenitors, we used a whole genome microarray for analyzing the gene expression profiles of proB-cells (CD19+/B220med/CD93+) isolated from Runx1+/+Cd79ahCre/+ and Runx1fl/flCd79ahCre/+ mice. Two independent experiments were peformed.