Project description:Aberrant activation of RAS/MAPK signaling is a driver of over one third of all human carcinomas. The homologous transcription factors ETS1 and ETS2 mediate the activation of gene expression programs downstream of RAS/MAPK signaling. ETS1 is important for oncogenesis in many tumor types. However, ETS2 can act as an oncogene in some cellular backgrounds, and as a tumor suppressor in others, and the molecular mechanism responsible for this cell-type specific function remains unknown. Here, we show that ETS1 and ETS2 regulate a cell migration gene expression program in opposite directions, and provide the first comparison of the ETS1 and ETS2 cistromes. This genomic data, and an ETS1 deletion line are used to show that the opposite function of ETS2 is due to binding site competition and a weaker activation function of ETS2 compared to ETS1. This weaker activation was mapped to the ETS2 N-terminus and a specific interaction with the co-repressor BS69 (ZMYND11). Gene expression data from tumor cohorts was then used to show that BS69 expression level in tumors correlates with oncogenic and tumor suppressive roles of ETS2. Therefore, these data indicate a novel and specific mechanism allowing ETS2 to switch between oncogenic and tumor suppressive functions in a cell-type specific manner.
Project description:Aberrant activation of RAS/MAPK signaling is a driver of over one third of all human carcinomas. The homologous transcription factors ETS1 and ETS2 mediate the activation of gene expression programs downstream of RAS/MAPK signaling. ETS1 is important for oncogenesis in many tumor types. However, ETS2 can act as an oncogene in some cellular backgrounds, and as a tumor suppressor in others, and the molecular mechanism responsible for this cell-type specific function remains unknown. Here, we show that ETS1 and ETS2 regulate a cell migration gene expression program in opposite directions, and provide the first comparison of the ETS1 and ETS2 cistromes. This genomic data, and an ETS1 deletion line are used to show that the opposite function of ETS2 is due to binding site competition and a weaker activation function of ETS2 compared to ETS1. This weaker activation was mapped to the ETS2 N-terminus and a specific interaction with the co-repressor BS69 (ZMYND11). Gene expression data from tumor cohorts was then used to show that BS69 expression level in tumors correlates with oncogenic and tumor suppressive roles of ETS2. Therefore, these data indicate a novel and specific mechanism allowing ETS2 to switch between oncogenic and tumor suppressive functions in a cell-type specific manner.
Project description:Angiogenesis is a highly orchestrated process involving complex crosstalk between several endothelial cell (EC) processes including cell cycle, cell survival and migration. Transcription factors ETS1 and ETS2 are required for EC functions necessary for embryonic angiogenesis. However owing to the lethal nature of the double mutant embryo, the specific gene targets of these factors are yet to be identified. In the current study, we try to elucidate the effect of endothelial cell specific deletion of Ets1 and Ets2 on post natal angiogenesis and characterize the downstream regulatory pathways. Deletion of Ets1 and Ets2, restricted to endothelial cells in new born mice (P1-P3), reduced retinal angiogenesis. Similarly, EC infiltration and invasion into matrigel plugs subsided when matrigel admixed with mouse mammary tumor cells was injected into adult mice with inactivated Ets1 and Ets2 specifically in ECs. Expression of key cell cycle and cell survival regulators were diminished in double mutant cells as compared to controls. In addition, both these factors were found to occupy the enhancer regions of the target genes. Deletion of Ets1 and Ets2 in cultured aortic EC resulted in altered cell cycle phases with a G2/M phase arrest and increased sensitivity to apoptosis in vitro. These results demonstrate that deletion of Ets1 and Ets2 in endothelial cells inhibits angiogenesis by altering cell cycle progression and decreasing cell survival.
Project description:Angiogenesis is a highly orchestrated process involving complex crosstalk between several endothelial cell (EC) processes including cell cycle, cell survival and migration. Transcription factors ETS1 and ETS2 are required for EC functions necessary for embryonic angiogenesis. However owing to the lethal nature of the double mutant embryo, the specific gene targets of these factors are yet to be identified. In the current study, we try to elucidate the effect of endothelial cell specific deletion of Ets1 and Ets2 on post natal angiogenesis and characterize the downstream regulatory pathways. Deletion of Ets1 and Ets2, restricted to endothelial cells in new born mice (P1-P3), reduced retinal angiogenesis. Similarly, EC infiltration and invasion into matrigel plugs subsided when matrigel admixed with mouse mammary tumor cells was injected into adult mice with inactivated Ets1 and Ets2 specifically in ECs. Expression of key cell cycle and cell survival regulators were diminished in double mutant cells as compared to controls. In addition, both these factors were found to occupy the enhancer regions of the target genes. Deletion of Ets1 and Ets2 in cultured aortic EC resulted in altered cell cycle phases with a G2/M phase arrest and increased sensitivity to apoptosis in vitro. These results demonstrate that deletion of Ets1 and Ets2 in endothelial cells inhibits angiogenesis by altering cell cycle progression and decreasing cell survival.
Project description:We explored the role of mammalian ETS1/2 and Mesp homologues of cardiogenic transcription factors of Ciona intestinalis, to convert primary human dermal fibroblasts into cardiac progenitors. ETS1/2 and Mesp homologues of cardiogenic transcription factors of Ciona intestinalis, to convert primary human dermal fibroblasts into cardiac progenitors. Here we show murine Ets2 has an obligatory role for directing cardiac progenitors during cardiopoesis in embryonic stem cells. ETS2 converted fibroblasts into KDR/Flk1+ replicative cells but, like the purported cardiac master regulatory gene Mesp1, could not by itself generate cardiac progenitors de novo from fibroblasts. Co-expression of both Ets2 and Mesp1, however, successfully reprogrammed differentiated fibroblasts into cardiac progenitors, as shown by the de novo appearance of core cardiac transcription factors, gap junction proteins, sarcomeric proteins, electrical activity and contractility. ETS2 and Mesp1 sit at the pinnacle of the cardiopoesis regulatory hierarchy and are well suited for treating human heart disease. Co-expression of both Ets2 and Mesp1, reprogrammed differentiated fibroblasts into cardiac progenitors
Project description:We explored the role of mammalian ETS1/2 and Mesp homologues of cardiogenic transcription factors of Ciona intestinalis, to convert primary human dermal fibroblasts into cardiac progenitors. ETS1/2 and Mesp homologues of cardiogenic transcription factors of Ciona intestinalis, to convert primary human dermal fibroblasts into cardiac progenitors. Here we show murine Ets2 has an obligatory role for directing cardiac progenitors during cardiopoesis in embryonic stem cells. ETS2 converted fibroblasts into KDR/Flk1+ replicative cells but, like the purported cardiac master regulatory gene Mesp1, could not by itself generate cardiac progenitors de novo from fibroblasts. Co-expression of both Ets2 and Mesp1, however, successfully reprogrammed differentiated fibroblasts into cardiac progenitors, as shown by the de novo appearance of core cardiac transcription factors, gap junction proteins, sarcomeric proteins, electrical activity and contractility. ETS2 and Mesp1 sit at the pinnacle of the cardiopoesis regulatory hierarchy and are well suited for treating human heart disease. Co-expression of both Ets2 and Mesp1, reprogrammed differentiated fibroblasts into cardiac progenitors All sample were done in triplicates, controls were NHDF and ETS2 only infected cells. NHDF were first infected with Doxycyline redulated (Doxy-) ETS2 lentivirus and supplemented with doxycycline for 1 week, sequentially cells were infected with Doxy-Mesp1 and treated for 1 more week. Cells were then aggegated to form EB and hangdrop for 1 week, at the end of that period cells were plated and samples were taken every 24 hrs
Project description:We performed ChIP-Seq for Ets1 and histone modifications in P5424 thymic cells, without and with Ets1 knockdown via shRNA. Overall, we find that loss of Ets1 results in specific, higher occupancy of H3K4me1-marked nucleosomes at the Ets1 binding site, but not H3K4me3 nucleosomes. We verified the specificity of this mechanism as Ets1-dependent by also computing H3K4me1 and 3 nucleosome occupancy in hypersensitive, Ets1-depleted sites. This effect was also found in primary WT DN+DP Ets1 sites. Overall, this suggests that Ets1 induces chromatin remodeling and that its loss increases H3K4me1 nucleosome occupancy in bound sites, with levels of H3K4me3 comparatively unchanged, thus reducing the activation status of these enhancers Genome-wide analysis via ChIP-Seq for Ets1, H3K4me1 and H3K4me3 in WT, sh-scramble and sh-Ets1 the P5424 thymic cell line