Project description:Analysis of the transcriptional response to treatment with glucocorticoids in human fibroblasts entering oncogene-induced senescence.
Project description:Analysis of the differential binding of EGR1 to chromatin in human fibroblasts entering oncogene-induced senescence, with and without clobetasol.
Project description:In this study we used CRISPR/Cas9 to generate KO clones of the HEK-RAF-ER cell line that lack expression of EGR1, FOS and profiled the transcriptome after inducing RAF/MAPK signaling.
Project description:Human bone marrow stromal cells (BMSCs) are key elements of the hematopoietic environment and they play a central role in bone and bone marrow physiology. However, how key BMSC functions are regulated is largely unknown. We analyzed the role of the immediate early response transcription factor EGR1 as key BMSC regulator and found that EGR1 was highly expressed in prospectively-isolated primary BMSCs, downregulated upon culture, and lower in non-CFU-F-containing CD45neg BM cells. Furthermore, EGR1 expression was lower in proliferative regenerating adult and fetal primary cells compared to adult steady-state BMSCs. Accordingly, EGR1 overexpression markedly decreased BMSC proliferation but considerably improved hematopoietic stroma support function as indicated by an increased production of transplantable CD34+CD90+ hematopoietic stem cells in expansion co-cultures. The improvement of BMSC stroma support function was mediated by increased expression of hematopoietic supporting genes, such as VCAM1 and CCL28. On the other hand, EGR1 knockdown increased ROS-mediated BMSC proliferation, and clearly reduced BMSC hematopoietic stroma support potential. These findings thus show that EGR1 is a key BMSC transcription factor with a dual role in regulating proliferation and hematopoietic stroma support function that is controlling a genetic program to coordinate the specific functions of BMSC in their different biological contexts.
Project description:Previous studies have revealed that UV-stimulation of a variety of cells leads to activation of the EGF receptor, induction of Egr1, growth inhibition and apoptosis. On the other hand both Egr1 and EGF receptor activation are implicated in promoting the progression of prostate cancer. We treated M12 tumorigenic prostate epithelial cells which express little Egr1 with UV irradiation which rapidly activated the EGF receptor and elevated Egr1. Treatment with specific EGFR and ERKI/II inhibitors (PD153035 and UO126, respectively) confirmed that the upregulation of Egr1 was downstream of EGFR and ERKI/II Map kinase pathway. ChIP on chip experiments using Egr1 antibody identified 288 significantly bound promoters upon UV stimulation. Of these target genes, 40% had consensus Egr1 site in their promoters, considerably greater than that expected by chance (p < 0.005). The array binding results were validated by PCR analysis of 25 genes using DNA from conventional IP experiment. Affymetrix gene expression analysis of UV treated and control cells confirmed that a significant number of these bound promoters showed gene expression changes. Addition of siRNA to Egr1 confirmed that the gene expression changes were dependent upon Egr1 expression. Addition of EGF led to similar expression changes for nine tested genes. Proliferation and apoptosis assays confirmed that M12 cells undergo growth arrest and apoptosis following UV irradiation. Moreover, addition of EGF also promoted significant growth inhibition. These results indicate the M12 cells undergo a EGF receptor dependent apoptosis response upon UV-stimulation and that Egr1 mediates the regulation of numerous genes downstream of the EGF receptor that are associated with this response. Keywords: UV treatment analysis duplicated experiment for Affymetrix gene expression analysis and Chip-on-Chip analysis.
Project description:To gain insight into the function of DNA-PKcs within immune cells, we performed a quantitative phosphoproteomic screen in T cells to identify first order phosphorylation targets of DNA-PKcs. Results indicate that DNA-PKcs phosphorylates the transcription factor Egr1 (early growth response protein 1) at S301. Expression of Egr1 is induced early upon T cell activation and dictates T cell response by modulating expression of cytokines and key costimulatory molecules. Mutation of serine 301 to alanine via CRISPR-Cas9 resulted in increased proteasomal degradation of Egr1 and a decrease in Egr1-dependent transcription of IL2 (interleukin-2) in activated T cells. Our findings identify DNA-PKcs as a critical intermediary link between T cell activation and T cell fate and a novel phosphosite involved in regulating Egr1 activity.