Project description:To investigate roles for Tbx20 in endocardium, we ablated Tbx20 utilizing Tie2Cre. Tie2Cre;Tbx20 mutants died at E14, exhibiting defects in multiple aspects of cardiac septation. Although endocardial cells lacking Tbx20 were able to undergo endothelial-to-mesenchymal transition, cushion mesenchymal cells lacking Tbx20 did not disperse normally. Non-cell autonomous roles of endocardial Tbx20 were also revealed, as evidenced by decreased myocardialization of outflow tract and failure of dorsal mesenchymal protrusion formation in mutants. To examine how ablation of Tbx20 in endocardial lineages affected gene expression, we performed global gene expression analysis on purified endocardial lineages. E12.5 hearts were dissociated, and Tie2Cre;RosatdTom lineage traced cells of controls and mutants were isolated by fluorescence activated cell sorting (FACS), after exclusion of blood cells (Ter119+, CD41+ and/or CD45+). Mutant endocardial lineages exhibited decreased expression of genes associated with extracellular matrix and cell migration. E12.5 hearts were dissociated, and Tie2Cre;RosatdTom lineage traced cells of controls and mutants were isolated by fluorescence activated cell sorting (FACS), after exclusion of blood cells (Ter119+, CD41+ and/or CD45+). FACS sorted Tie2Cre lineage from E12.5 hearts: Tie2Cre;Tbx20 +/loxP Control hearts versus Tie2Cre;Tbx20 loxP/- mutant hearts
Project description:To investigate roles for Tbx20 in endocardium, we ablated Tbx20 utilizing Tie2Cre. Tie2Cre;Tbx20 mutants died at E14, exhibiting defects in multiple aspects of cardiac septation. Although endocardial cells lacking Tbx20 were able to undergo endothelial-to-mesenchymal transition, cushion mesenchymal cells lacking Tbx20 did not disperse normally. Non-cell autonomous roles of endocardial Tbx20 were also revealed, as evidenced by decreased myocardialization of outflow tract and failure of dorsal mesenchymal protrusion formation in mutants. To examine how ablation of Tbx20 in endocardial lineages affected gene expression, we performed global gene expression analysis on purified endocardial lineages. E12.5 hearts were dissociated, and Tie2Cre;RosatdTom lineage traced cells of controls and mutants were isolated by fluorescence activated cell sorting (FACS), after exclusion of blood cells (Ter119+, CD41+ and/or CD45+). Mutant endocardial lineages exhibited decreased expression of genes associated with extracellular matrix and cell migration. E12.5 hearts were dissociated, and Tie2Cre;RosatdTom lineage traced cells of controls and mutants were isolated by fluorescence activated cell sorting (FACS), after exclusion of blood cells (Ter119+, CD41+ and/or CD45+).
Project description:In order to identify the targets of GATA4-FOG2 action in mammalian heart development we performed Affymetrix microarray comparisons of gene expression in normal and mutant at embryonic (E) day E12.5 hearts. We compared RNA samples from both Fog2-null and Gata4ki/ki mutant E12.5 hearts to the wild-type control E12.5 hearts. We reasoned that as the phenotypes of the Fog2 knockout and Gata4ki/ki mutation (a V217G mutation that specifically cripples the interaction between GATA4 and FOG proteins) are similar, we should expect to identify a similar set of differentially expressed genes in both experiments. As an additional control, we expected to find the Fog2 gene expression absent in the mutant (null) Fog2 cardiac sample, but not Gata4ki/ki sample.
Project description:In order to identify the targets of GATA4-FOG2 action in mammalian heart development we performed Affymetrix microarray comparisons of gene expression in normal and mutant at embryonic (E) day E12.5 hearts. We compared RNA samples from both Fog2-null and Gata4ki/ki mutant E12.5 hearts to the wild-type control E12.5 hearts. We reasoned that as the phenotypes of the Fog2 knockout and Gata4ki/ki mutation (a V217G mutation that specifically cripples the interaction between GATA4 and FOG proteins) are similar, we should expect to identify a similar set of differentially expressed genes in both experiments. As an additional control, we expected to find the Fog2 gene expression absent in the mutant (null) Fog2 cardiac sample, but not Gata4ki/ki sample. We have analyzed 6 RNA samples total (3 from control hearts, 2 from FOG2 null hearts and 1 from GATA4ki hearts)
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.