title: The glucocorticoid receptor is tethered to DNA-bound Oct-1 at the mouse gonadotropin-releasing hormone distal negative glucocorticoid response element.
abstract: An element required for glucocorticoid repression of mouse gonadotropin-releasing hormone (GnRH) gene transcription, the distal negative glucocorticoid response element (nGRE), is not bound directly by glucocorticoid receptors (GRs) but is recognized by Oct-1 present in GT1-7 cell nuclear extracts or by Oct-1 purified from HeLa cells. Furthermore, purified full-length GRs interact directly with purified Oct-1 bound to the distal nGRE. Increasing the extent of distal nGRE match to an Oct-1 consensus site not only increases the affinity of Oct-1 binding, but also alters the conformation of DNA-bound Oct-1 and the pattern of protein DNA complexes formed in vitro with GT1-7 cell nuclear extracts. In addition, the interaction of purified GR with DNA-bound Oct-1 is altered when Oct-1 is bound to the consensus Oct-1 site. Mutation of the distal nGRE to a consensus Oct-1 site is also associated with reduced glucocorticoid repression in transfected GT1-7 cells. Furthermore, repression of GnRH gene transcription by 12-O-tetradecanoylphorbol-13-acetate, which utilizes sequences that overlap with the nGRE, is reversed by this distal nGRE mutation leading to activation of GnRH gene transcription. Thus, changes in the assembly of multi-protein complexes at the distal nGRE can influence the regulation of GnRH gene transcription.
authors.affiliation: Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA.
authors.forename: U R
authors.initials: UR
authors.lastname: Chandran
authors.forename: B S
authors.initials: BS
authors.lastname: Warren
authors.forename: C T
authors.initials: CT
authors.lastname: Baumann
authors.forename: G L
authors.initials: GL
authors.lastname: Hager
authors.forename: D B
authors.initials: DB
authors.lastname: DeFranco
mesh_terms: D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D004268:DNA-Binding Proteins / Q000378:metabolism*; D005938:Glucocorticoids / Q000378:metabolism*; D007987:Gonadotropin-Releasing Hormone / Q000378:metabolism*; D006367:HeLa Cells; D051863:Host Cell Factor C1; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D050811:Octamer Transcription Factor-1; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D011965:Receptors, Glucocorticoid / Q000378:metabolism*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014157:Transcription Factors / Q000378:metabolism*
chemical_list: D004268:DNA-Binding Proteins; D005938:Glucocorticoids; C497692:HCFC1 protein, human; C497693:Hcfc1 protein, mouse; D051863:Host Cell Factor C1; D050811:Octamer Transcription Factor-1; C494165:POU2F1 protein, human; C494166:Pou2f1 protein, mouse; D011965:Receptors, Glucocorticoid; D014157:Transcription Factors; D007987:Gonadotropin-Releasing Hormone; D013755:Tetradecanoylphorbol Acetate