Project description:FGF4 has key role in self-renewal and differentiation of Embryonic stem cell, and Fgf4 is activated by direct binding of ESW-OCT-4 through its enhancer
Project description:Protein kinase signalling is a major mechanism by which embryonic stem cell pluripotency and differentiation is controlled. However, the pathways and components that regulate embryonic stem cell identity have not been systematically defined. Here, we employ FGF4 signalling as a model system to investigate phosphoproteome dynamics in differentiating mouse embryonic stem cells. We report identification and quantitation of more than 10,000 phosphopeptides, of which hundreds of phosphophoylation sites are regulated more than 2-fold by acute FGF4 stimulation. We hypothesise that phosphorylation sites in this dataset are relevant for regulating the transition of mouse embryonic stem cells from pluripotency towards lineage specific differentiation.
Project description:POU5F1 (more commonly known as Oct-4/3) is one of the stem cell markers and affects direction of differentiation in embryonic stem cells. To investigate whether cells of mesenchymal origin acquire embryonic phenotype, we generated a human cell line of mesodermal origin with overexpression of the chimeric POU5F1 gene with physiological co-activator EWS, which is driven by the potent EWS promoter by translocation. The cell line termed Pooh (POU5F1/Oct-4/3 overexpressing human) cells expressed embryonic stem cell genes such as Nanog and also non-translocated POU5F1, lost mesenchymal phenotypes, and exhibited embryonal stem cell-like alveolar structure when implanted into the subcutaneous tissue of immunodeficient mice. Hierarchical analysis by microchip analysis and cell surface analysis revealed that Pooh cells are subcategorized into the group of human embryonic stem cells and embryonal carcinoma cells. These results imply that cells of mesenchymal origin can partially be traced back to cells to embryonic phenotype by the POU5F1 gene in collaboration with the potent cis-regulatory element and the fused co-activator. Experiment Overall Design: Pooh cells was generated from primary or first passage cells of pelvic tumor (Yamaguchi et al., Genes Chromosomes Cancer. 2005 Jun;43(2):217-22), and cultured in tissue culture dishes (100 mm, Becton Dickinson) in the G031101 medium (Med Shirotori, Tokyo). All cultures were maintained at 37°C in a humidified atmosphere containing 95% air and 5% CO2.
Project description:A small number of transcription factors, including Oct-3/4 and Sox2, constitute the transcriptional network that maintains pluripotency in embryonic stem (ES) cells. Previous reports suggested that some of these factors form a complex that binds the Oct-Sox element, a composite sequence consisting of closely juxtaposed Oct-3/4-binding and Sox2-binding sites. However, little is known regarding the components of the complex. In this study, we show that Sall4, a member of the Spalt-like family of proteins, directly interacts with Sox2 and Oct-3/4. Sall4 in combination with Sox2 or Oct-3/4 simultaneously occupies the Oct-Sox elements in mouse ES cells. Sall4 knockdown led to differentiation of ES cells. Overexpression of Sall4 in ES cells increased reporter activities in a luciferase assay when the Pou5f1- or Nanog-derived Oct-Sox element was included in the reporter. Microarray analyses revealed that Sall4 and Sox2 bound to the same genes in ES cells significantly more frequently than expected from random coincidence. These factors appeared to bind the promoter regions of a subset of the Sall4- and Sox2-double-positive genes in precisely similar distribution patterns along the promoter regions, suggesting that Sall4 and Sox2 associate with such Sall4/Sox2-overlapping genes as a complex. Importantly, gene ontology analyses indicated that the Sall4/Sox2-overlapping gene set is enriched for genes involved in maintaining pluripotency. Sall4/Sox2/Oct-3/4-triple-positive genes identified by referring to a previous study identifying Oct-3/4-bound genes in ES cells were further enriched for pluripotency genes than Sall4/Sox2-double-positive genes. These results demonstrate that Sall4 contributes to the transcriptional network operating in pluripotent cells, together with Oct-3/4 and Sox2.
Project description:A small number of transcription factors, including Oct-3/4 and Sox2, constitute the transcriptional network that maintains pluripotency in embryonic stem (ES) cells. Previous reports suggested that some of these factors form a complex that binds the Oct-Sox element, a composite sequence consisting of closely juxtaposed Oct-3/4-binding and Sox2-binding sites. However, little is known regarding the components of the complex. In this study, we show that Sall4, a member of the Spalt-like family of proteins, directly interacts with Sox2 and Oct-3/4. Sall4 in combination with Sox2 or Oct-3/4 simultaneously occupies the Oct-Sox elements in mouse ES cells. Sall4 knockdown led to differentiation of ES cells. Overexpression of Sall4 in ES cells increased reporter activities in a luciferase assay when the Pou5f1- or Nanog-derived Oct-Sox element was included in the reporter. Microarray analyses revealed that Sall4 and Sox2 bound to the same genes in ES cells significantly more frequently than expected from random coincidence. These factors appeared to bind the promoter regions of a subset of the Sall4- and Sox2-double-positive genes in precisely similar distribution patterns along the promoter regions, suggesting that Sall4 and Sox2 associate with such Sall4/Sox2-overlapping genes as a complex. Importantly, gene ontology analyses indicated that the Sall4/Sox2-overlapping gene set is enriched for genes involved in maintaining pluripotency. Sall4/Sox2/Oct-3/4-triple-positive genes identified by referring to a previous study identifying Oct-3/4-bound genes in ES cells were further enriched for pluripotency genes than Sall4/Sox2-double-positive genes. These results demonstrate that Sall4 contributes to the transcriptional network operating in pluripotent cells, together with Oct-3/4 and Sox2. ChIP-on-chip experiments using anti-Sall4 or anti-Sox2 antibody were performed.
Project description:Ewing sarcoma (EWS) is a malignant pediatric bone cancer. Most Ewing sarcomas are driven by EWS-FLI1 oncogenic transcription factor that plays roles in transcriptional regulation, DNA damage response, cell cycle checkpoint control, and alternative splicing. USP1, a deubiquitylase which regulates DNA damage and replication stress responses, is overexpressed at both the mRNA and protein levels in EWS cell lines compared to human mesenchymal stem cells, the EWS cell of origin. The functional significance of high USP1 expression in Ewing sarcoma is not known. Here, we identify USP1 as a transcriptional target of EWS-FLI1 and a key regulator of EWS cell survival. We show that EWS-FLI1 knockdown decreases USP1 mRNA and protein levels. ChIP and ChIP-seq analyses show EWS-FLI1 occupancy on the USP1 promoter. Importantly, USP1 knockdown or inhibition arrests EWS cell growth and induces cell death by apoptosis. We observe destabilization of Survivin (also known as BIRC5 or IAP4) and activation of caspases-3 and -7 following USP1 knockdown or inhibition in the absence of external DNA damage stimuli. Notably, EWS cells display hypersensitivity to combinatorial treatment of doxorubicin or etoposide, EWS standard of care drugs, and USP1 inhibitor compared to single agents alone. Together, our study demonstrates that USP1 is regulated by EWS-FLI1, the USP1-Survivin axis promotes EWS cell survival, and USP1 inhibition sensitizes EWS cells to standard of care chemotherapy.
Project description:POU5F1 (more commonly known as Oct-4/3) is one of the stem cell markers and affects direction of differentiation in embryonic stem cells. To investigate whether cells of mesenchymal origin acquire embryonic phenotype, we generated a human cell line of mesodermal origin with overexpression of the chimeric POU5F1 gene with physiological co-activator EWS, which is driven by the potent EWS promoter by translocation. The cell line termed Pooh (POU5F1/Oct-4/3 overexpressing human) cells expressed embryonic stem cell genes such as Nanog and also non-translocated POU5F1, lost mesenchymal phenotypes, and exhibited embryonal stem cell-like alveolar structure when implanted into the subcutaneous tissue of immunodeficient mice. Hierarchical analysis by microchip analysis and cell surface analysis revealed that Pooh cells are subcategorized into the group of human embryonic stem cells and embryonal carcinoma cells. These results imply that cells of mesenchymal origin can partially be traced back to cells to embryonic phenotype by the POU5F1 gene in collaboration with the potent cis-regulatory element and the fused co-activator. Keywords: Involvement of chimeric POU5F1 (Oct-4/3) with physiological co-activator EWS in mesenchymal-embryonic transition of human cells