ABSTRACT: Regulation of Megakaryocytic differentiation in Cell Line Models by Dynamic Combinatorial Interactions of RUNX1 with Its Cooperating Partners
Project description:Regulation of Megakaryocytic differentiation in Cell Line Models by Dynamic Combinatorial Interactions of RUNX1 with Its Cooperating Partners
Project description:Regulation of Megakaryocytic differentiation in Cell Line Models by Dynamic Combinatorial Interactions of RUNX1 with Its Cooperating Partners Examination of RUNX1 binding in K562 cells, before and following TPA induction and CMK cells. Examination of GATA1 and FOS binding and H3K4me1 and H3K27me3 modification levels following TPA induction in K562 cells.
Project description:This SuperSeries is composed of the following subset Series: GSE24777: Regulation of Megakaryocytic differentiation in Cell Line Models by Dynamic Combinatorial Interactions of RUNX1 with Its Cooperating Partners GSE24778: Expresssion data in K562 cells, before and after TPA induction and including a RUNX1 knockout construct or a control structure Refer to individual Series
Project description:Combinatorial transcription factor (TF) interactions control cellular phenotypes and therefore underpin stem cell formation, maintenance and differentiation. Here we report the genome-wide binding patterns and combinatorial interactions for 10 key regulators of blood stem/progenitor cells (Scl/Tal1, Lyl1, Lmo2, Gata2, Runx1, Meis1, Pu.1, Erg, Fli-1, Gfi1b) thus providing the most comprehensive TF dataset for any adult stem/progenitor cell type to date. Genome-wide computational analysis of complex binding patterns followed by functional validation revealed the following: First, a previously unrecognized combinatorial interaction between a heptad of TFs (Scl, Lyl1, Lmo2, Gata2, Runx1, Erg, Fli-1). Second, we implicate direct protein-protein interactions between four key regulators (Runx1, Gata2, Scl, Erg) in stabilising complex binding to DNA. Third, Runx1+/-::Gata2+/- compound heterozygous mice are not viable with severe haematopoietic defects at midgestation. Taken together, this study demonstrates the power of genome-wide analysis in generating novel functional insights into the transcriptional control of stem and progenitor cells. 10 Samples (9 Transcription Factors and 1 Histone Modification) and 1 Control (IgG). All from the same cell line, a haematopoietic progenitor cell line (HPC-7).
Project description:A high incidence of acute megakaryoblastic leukemia (AMKL) in Down syndrome patients implies that chromosome 21 genes have a pivotal role in AMKL development, but the functional contribution of individual genes remains elusive. Here, we report that SON, a chromosome 21-encoded DNA- and RNA-binding protein, inhibits megakaryocytic differentiation by suppressing RUNX1 and the megakaryocytic gene expression program. As megakaryocytic progenitors differentiate, SON expression is drastically reduced, with mature megakaryocytes having the lowest levels. In contrast, AMKL cells express an aberrantly high level of SON, and knockdown of SON induced the onset of megakaryocytic differentiation in AMKL cell lines. Genome-wide transcriptome analyses revealed that SON knockdown turns on the expression of pro-megakaryocytic genes while reducing erythroid gene expression. Mechanistically, SON represses RUNX1 expression by directly binding to the proximal promoter and two enhancer regions, the known +23 kb enhancer and the novel +139 kb enhancer, at the RUNX1 locus to suppress H3K4 methylation. In addition, SON represses the expression of the AP-1 complex subunits JUN, JUNB and FOSB which are required for late megakaryocytic gene expression. Our findings define SON as a negative regulator of RUNX1 and megakaryocytic differentiation, implicating SON overexpression in impaired differentiation during AMKL development.
Project description:Combinatorial transcription factor (TF) interactions control cellular phenotypes and therefore underpin stem cell formation, maintenance and differentiation. Here we report the genome-wide binding patterns and combinatorial interactions for 10 key regulators of blood stem/progenitor cells (Scl/Tal1, Lyl1, Lmo2, Gata2, Runx1, Meis1, Pu.1, Erg, Fli-1, Gfi1b) thus providing the most comprehensive TF dataset for any adult stem/progenitor cell type to date. Genome-wide computational analysis of complex binding patterns followed by functional validation revealed the following: First, a previously unrecognized combinatorial interaction between a heptad of TFs (Scl, Lyl1, Lmo2, Gata2, Runx1, Erg, Fli-1). Second, we implicate direct protein-protein interactions between four key regulators (Runx1, Gata2, Scl, Erg) in stabilising complex binding to DNA. Third, Runx1+/-::Gata2+/- compound heterozygous mice are not viable with severe haematopoietic defects at midgestation. Taken together, this study demonstrates the power of genome-wide analysis in generating novel functional insights into the transcriptional control of stem and progenitor cells.
Project description:Familial platelet disorder with predisposition to acute myeloid leukemia (FPD/AML) is an autosomal dominant disease of the hematopoietic system, which is caused by heterozygous mutations in RUNX1. FPD/AML patients have a bleeding disorder characterized by thrombocytopenia with reduced platelet numbers and functions, and a tendency to develop AML. Currently no suitable animal models exist for FPD/AML as Runx1+/- mice and zebrafish do not develop bleeding disorders or leukemia. Here we derived induced pluripotent stem cells (iPSCs) from two patients in a family with FPD/AML, and found that the FPD iPSCs display defects in megakaryocytic differentiation in vitro. We corrected the RUNX1 mutation in one FPD iPSC line through gene targeting, which led to normalization of megakaryopoiesis of the iPSCs in culture. Our results demonstrate successful in vitro modeling of FPD with patient-specific iPSCs and confirm that RUNX1 mutations are responsible for megakaryopoietic defects in FPD patients.
Project description:Familial platelet disorder with predisposition to acute myeloid leukemia (FPD/AML) is an autosomal dominant disease of the hematopoietic system, which is caused by heterozygous mutations in RUNX1. FPD/AML patients have a bleeding disorder characterized by thrombocytopenia with reduced platelet numbers and functions, and a tendency to develop AML. Currently no suitable animal models exist for FPD/AML as Runx1+/- mice and zebrafish do not develop bleeding disorders or leukemia. Here we derived induced pluripotent stem cells (iPSCs) from two patients in a family with FPD/AML, and found that the FPD iPSCs display defects in megakaryocytic differentiation in vitro. We corrected the RUNX1 mutation in one FPD iPSC line through gene targeting, which led to normalization of megakaryopoiesis of the iPSCs in culture. Our results demonstrate successful in vitro modeling of FPD with patient-specific iPSCs and confirm that RUNX1 mutations are responsible for megakaryopoietic defects in FPD patients. Here, we derived iPSCs from two FPD/AML patients and demonstrated that these iPSCs have a megakaryopoietic defect in culture. Importantly we were able to rescue the megakaryopoietic defect by correcting the RUNX1 mutation with a gene targeting strategy enhanced by zinc finger nucleases (ZFNs). Three independent samples were obtained for each time point.
Project description:The transcription factor RUNX1 is a critical regulator of developmental hematopoiesis and is frequently disrupted in leukemia. Runx1 is a large, complex gene that is expressed from two alternative promoters under the spatiotemporal control of multiple hematopoietic enhancers. To dissect the dynamic regulation of Runx1 in hematopoietic development, we analyzed its three-dimensional chromatin conformation in mouse embryonic stem cell (ESC) differentiation cultures. Runx1 resides in a 1.1 Mb topologically associating domain (TAD) demarcated by convergent CTCF motifs. As ESCs differentiate to mesoderm, chromatin accessibility, Runx1 enhancer-promoter (E-P) interactions, and CTCF-CTCF interactions increased in the TAD, along with initiation of Runx1 expression from the P2 promoter. Differentiation to hematopoietic progenitor cells was associated with the formation of tissue-specific sub-TADs over Runx1, a shift in E-P interactions, P1 promoter demethylation, and robust expression from both Runx1 promoters. Deletions of promoter-proximal CTCF sites at the sub-TAD boundaries had no obvious effects on E-P interactions but led to partial loss of domain structure, mildly affected gene expression, and delayed hematopoietic development. Together, our analyses of gene regulation at a large multi-promoter developmental gene revealed that dynamic sub-TAD chromatin boundaries play a role in establishing TAD structure and coordinated gene expression.