title: c-Myb and members of the c-Ets family of transcription factors act as molecular switches to mediate opposite steroid regulation of the human glucocorticoid receptor 1A promoter.
abstract: Steroid auto-regulation of the human glucocorticoid receptor (hGR) 1A promoter in lymphoblast cells resides largely in two DNA elements (footprints 11 and 12). We show here that c-Myb and c-Ets family members (Ets-1/2, PU.1, and Spi-B) control hGR 1A promoter regulation in T- and B-lymphoblast cells. Two T-lymphoblast lines, CEM-C7 and Jurkat, contain high levels of c-Myb and low levels of PU.1, whereas the opposite is true in IM-9 B-lymphoblasts. In Jurkat cells, overexpression of c-Ets-1, c-Ets-2, or PU.1 effectively represses dexamethasone-mediated up-regulation of an hGR 1A promoter-luciferase reporter gene, as do dominant negative c-Myb (c-Myb DNA-binding domain) or Ets proteins (Ets-2 DNA-binding domain). Overexpression of c-Myb in IM-9 cells confers hormone-dependent up-regulation to the hGR 1A promoter reporter gene. Chromatin immunoprecipitation assays show that hormone treatment causes the recruitment of hGR and c-Myb to the hGR 1A promoter in CEM-C7 cells, whereas hGR and PU.1 are recruited to this promoter in IM-9 cells. These observations suggest that the specific transcription factor that binds to footprint 12, when hGR binds to the adjacent footprint 11, determines the direction of hGR 1A promoter auto-regulation. This leads to a "molecular switch" model for auto-regulation of the hGR 1A promoter.
authors.affiliation: Department of Biochemistry and Molecular Biology and Stanley S. Scott Cancer Center, Louisiana State University Health Sciences Center, New Orleans, Louisiana 70112, USA.
authors.forename: Chuan-dong
authors.initials: CD
authors.lastname: Geng
authors.forename: Wayne V
authors.initials: WV
authors.lastname: Vedeckis
mesh_terms: D017209:Apoptosis; D001402:B-Lymphocytes / Q000378:metabolism*; D015153:Blotting, Western; D002460:Cell Line; D019070:Cell Lineage; D047369:Chromatin Immunoprecipitation; D004268:DNA-Binding Proteins / Q000096:biosynthesis*; D018274:Electroporation; D005091:Exons; D005786:Gene Expression Regulation; D005799:Genes, Dominant; D006801:Humans; D019169:Jurkat Cells; D007938:Leukemia / Q000378:metabolism; D008156:Luciferases / Q000378:metabolism; D008214:Lymphocytes / Q000378:metabolism; D008954:Models, Biological; D016133:Polymerase Chain Reaction; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D050784:Proto-Oncogene Protein c-ets-1 / Q000096:biosynthesis*; D050787:Proto-Oncogene Protein c-ets-2 / Q000096:biosynthesis*; D011518:Proto-Oncogene Proteins / Q000096:biosynthesis* / Q000378:metabolism; D050783:Proto-Oncogene Proteins c-ets / Q000378:metabolism / Q000502:physiology*; D020598:Proto-Oncogene Proteins c-myb / Q000378:metabolism / Q000502:physiology*; D011965:Receptors, Glucocorticoid / Q000235:genetics*; D013256:Steroids / Q000378:metabolism*; D013601:T-Lymphocytes / Q000166:cytology / Q000378:metabolism*; D015534:Trans-Activators / Q000096:biosynthesis* / Q000378:metabolism; D014157:Transcription Factors / Q000096:biosynthesis*; D014162:Transfection; D015854:Up-Regulation; D000099232:Proto-Oncogene Protein Spi-1
chemical_list: D004268:DNA-Binding Proteins; D008156:Luciferases; D050784:Proto-Oncogene Protein c-ets-1; D050787:Proto-Oncogene Protein c-ets-2; D011518:Proto-Oncogene Proteins; D050783:Proto-Oncogene Proteins c-ets; D020598:Proto-Oncogene Proteins c-myb; D011965:Receptors, Glucocorticoid; D013256:Steroids; D015534:Trans-Activators; D014157:Transcription Factors; D000099232:Proto-Oncogene Protein Spi-1; C494041:ETS1 protein, human; C076877:SPIB protein, human