Function of Directly Repeated Half-sites as Response Elements for Steroid Hormone Receptors

Aumais, Jonathan P.; Lee, Han S.; DeGannes, Chris; Horsford, Jonathan; White, John H.

doi:10.1074/jbc.271.21.12568

Cited by 76 publications

(56 citation statements)

References 67 publications

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“…Half-site orientation is also known to affect receptor binding as well as transcriptional activation (5). Although GR can bind to directly repeated half-sites with low affinity (68), structural studies revealed that GR preferentially binds to palindromic DNA sequences as a dimer in a "head-to-head" conformation (12). Consistent with these reports, both MR and GR demonstrated a stronger affinity for HRE2 in comparison to HRE1.…”

Section: Discussionsupporting

confidence: 74%

Aldosterone Modulates Steroid Receptor Binding to the Endothelin-1 Gene (edn1)

Stow

Gumz

Lynch

et al. 2009

Journal of Biological Chemistry

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Aldosterone and endothelin-1 (ET-1) act on collecting duct cells of the kidney and are important regulators of renal sodium transport and cardiovascular physiology. We recently identified the ET-1 gene (edn1) as a novel aldosterone-induced transcript. However, aldosterone action on edn1 has not been characterized at the present time. In this report, we show that aldosterone stimulated edn1 mRNA in acutely isolated rat inner medullary collecting duct cells ex vivo and ET-1 peptide in rat inner medulla in vivo. Aldosterone induction of edn1 mRNA occurred in cortical, outer medullary, and inner medullary collecting duct cells in vitro. Inspection of the edn1 promoter revealed two putative hormone response elements. Levels of heterogeneous nuclear RNA synthesis demonstrated that edn1 mRNA stimulation occurred at the level of transcription. RNA knockdowns corroborated pharmacological studies and demonstrated both mineralocorticoid receptor and glucocorticoid receptor participated in this response. Aldosterone resulted in dose-dependent nuclear translocation and binding of mineralocorticoid receptor and glucocorticoid receptor to the edn1 hormone response elements. Hormone receptors mediated the association of chromatin remodeling complexes, histone modification, and RNA polymerase II at the edn1 promoter. Direct interaction between aldosterone and ET-1 has important implications for renal and cardiovascular function.The steroid hormone aldosterone is critical for sodium homeostasis and blood pressure control. Aldosterone works by modulating the fine regulation of sodium reabsorption in the distal nephron and collecting duct of the kidney. Classic aldosterone action is mediated through the mineralocorticoid receptor (MR), 3 a member of the nuclear receptor family of proteins that function as ligand-dependent transcription factors (1). MR acts on cells of the distal nephron and collecting duct to stimulate transcription of genes involved in transepithelial sodium transport, including the epithelial sodium channel ␣ subunit (scnn1a, ␣ENaC), the sodium, potassium-ATPase ␣1 subunit (atp1a1), and the serum-and glucocorticoid-regulated kinase-1 (sgk1) (2). The increase in expression of genes involved in sodium transport results in net sodium reabsorption followed by in increase in extracellular fluid volume and a consequent increase in blood pressure. Indeed, MR antagonists such as spironolactone and eplerenone are used clinically as diuretic and anti-hypertensive agents (3). The mechanism of MR action is consistent with a classic steroid receptor mechanism (4). Prior to activation MR resides in the cytosol. Ligand binding induces a conformational change that releases chaperone proteins and reveals a nuclear localization signal. Nuclear MR binds directly to DNA at hormone response elements (HREs) in target genes to modulate their transcription. A typical HRE for MR consists of two receptor binding half-sites with the consensus sequence 5Ј-TGTTCT-3Ј, arranged as an inverted palindrome (1, 5). These HREs facilitate binding of...

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Section: Discussionsupporting

confidence: 74%

Aldosterone Modulates Steroid Receptor Binding to the Endothelin-1 Gene (edn1)

Stow

Gumz

Lynch

et al. 2009

Journal of Biological Chemistry

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“…The H19 promoter is devoid of canonical estrogen responsive elements, but exhibits several consensual or degenerated half-sites. Some studies have shown that the estrogen receptor can bind various direct or inverted repeats of the ERE half-sites (Kato et al, 1995;Aumais et al, 1996), so ERa could act on H19 promoter by a direct manner too.…”

Section: Discussionmentioning

confidence: 99%

Steroid hormones modulate H19 gene expression in both mammary gland and uterus

et al. 1999

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H19 is an imprinted and developmentally regulated gene whose product remains apparently untranslated. In a previous study on breast adenocarcinomas, we reported that overexpression of the H19 gene was signi®cantly correlated with the presence of steroid receptors, suggesting the putative role of hormones in H19 transcription. To determine the mode of steroid action, we have detected levels of H19 RNA synthesis during mammary gland development by in situ hybridization (ISH): two peaks of H19 transcription occur during puberty and pregnancy. Furthermore, we demonstrated by ISH that in the uterus H19 RNA synthesis is high during estrus and metestrus phases. To test steroid control of H19 transcription, ovariectomized and adrenalectomized mice were supplemented, 1 week after surgery, with 17-b-estradiol (E2, 20 mg/kg/day), progesterone (P, 1 mg/kg/day) or corticosterone (B, 0.3 mg/ kg/day) for 2 weeks. According to ISH data, E2 and to a lesser extent B stimulated H19 transcription in the uterus, whereas P inhibited it. To con®rm the in vivo results, in vitro experiments were performed using cultures of MCF-7 cells (a hormone-sensitive mammary cell line). E2 stimulated the endogenous H19 gene of this cell line and tamoxifen inhibited this e ect. Furthermore, we performed transient cotransfections in MCF-7, in HBL-100 (another hormone-sensitive mammary cell line) and in BT-20 (a hormone-insensitive mammary cell line) with various constructs of ERa (WT or mutated) and PR-A, in presence or absence of steroid hormones. We demonstrated that ERa up-regulated the H19 promoter in MCF-7 and in HBL-100, whereas PR-A did not have any e ect per se. Moreover, in MCF-7, PR-A antagonized clearly the ERa-mediated promoter enhancement, but in HBL-100 this counteracting e ect on the ERa up-regulation was not found. Interestingly, the same experiments performed in BT-20 cell line provided very similar results as those obtained in MCF-7 cells, with a clear down-regulation mediated by PR-A on the H19 promoter. All these in vitro data are in agreement with in vivo results. In addition, data obtained with ERa mutants indicate that H19 promoter activation is both ligand-dependent and ligand-independent. We have thus demonstrated that H19 gene expression is controlled by steroid hormones; furthermore, this gene is highly expressed in hormone-sensitive organs when the hormonal stimulation is accompanied with a morphological repair.

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“…The consensus nonpalindromic dimeric GRE1 and GRE2 substrates were from the MMTV and the tyrosine aminotransferase (TAT) promoters, respectively. The center of oligonucleotides GRE3-TOP and GRE3-BOT contained a palindromic GRE sequence reported to bind GR with high affinity (12). Oligonucleotides GRE4-TOP and GRE4-BOT contained a palindromic GRE designed at the end of the sequence identical to that used in a reported GR-DNA binding gel-shift study (17).…”

Section: Materials and Plasmid Preparation-allmentioning

confidence: 99%

“…In general, studies indicate that hormones are not required for stable GR binding to DNA in vitro (11)(12)(13)(14)(15)(16). Specifically, complexes of agonist triamcinolone acetonide and antagonist RU486 bound to GR have a comparable affinity for glucocorticoid response elements from different promoters (14 -16).…”

mentioning

confidence: 99%

Allosteric Effects of Dexamethasone and RU486 on Glucocorticoid Receptor-DNA Interactions

Pandit

Geissler

Harris

et al. 2002

Journal of Biological Chemistry

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The glucocorticoid receptor (GR) is a DNA-binding protein that can regulate the transcription of a large number of genes in a ligand-dependent fashion. Although much progress has been made on the mechanism of transcriptional regulation by GR, a potential allosteric effect of GR-binding ligands on specific GR-DNA interactions is controversial. In this study, gel-shift methods are used to measure the effects of a classical agonist dexamethasone and a prototypical antagonist RU486 on the in vitro interactions of GR with DNA substrates, which contain glucocorticoid response elements (GREs) from promoters of GR-regulated genes. These studies show that cell extracts containing human GR bind specifically and with high affinity to GREs in the absence of ligand. An agonist dexamethasone and antagonist RU486 do not affect the affinity of GR for DNA but subtly alter the electrophoretic mobility of the GR-DNA complex. Importantly, the dissociation rate of GR from DNA increases as a function of the concentration of GRE-containing DNA. At a fixed DNA concentration, dexamethasone-bound GR dissociates from DNA significantly faster than does ligand-free GR or RU486-bound GR. These results are consistent with a model for transcriptional activation in which a dynamic complex is formed between agonist-bound GR and DNA. The glucocorticoid receptor (GR)1 is a member of the steroid hormone receptor family of transcription factors that regulates a large number of genes in a hormone-or ligand-dependent manner. GR is predominantly cytosolic and requires association with heat shock proteins for ligand binding, a feature that has complicated in vitro structural studies of GR (1-6). The molecular mechanism by which hormones and small molecule ligands regulate GR-mediated gene expression is not clearly understood. A favored model is that hormone binding induces dissociation of heat shock proteins from the ligand-bound GR complex, which then translocates to the nucleus for sequencespecific DNA binding to GREs (7-10). However, the underlying mechanism for the expression of agonist versus antagonist activity for the steroid-bound GR-DNA complex is not clear.Attempts to study the allosteric effects of hormones on GR-DNA interactions in vitro have led to contradictory observations. In general, studies indicate that hormones are not required for stable GR binding to DNA in vitro (11-16). Specifically, complexes of agonist triamcinolone acetonide and antagonist RU486 bound to GR have a comparable affinity for glucocorticoid response elements from different promoters (14 -16). In contrast to these studies done on asymmetric GR binding sites, gel-shift experiments reported with GR and an artificial palindromic GRE suggest that ligands directly affect GR-DNA binding (17). The agonist dexamethasone enhances GR-DNA binding severalfold, whereas antagonists including RU486 have no effect on GR-DNA binding. However, this observation is contested by a report that also implements gelshift methods with a palindromic GRE substrate but uses in vitro transcribed...

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Function of Directly Repeated Half-sites as Response Elements for Steroid Hormone Receptors

Cited by 76 publications

References 67 publications

Aldosterone Modulates Steroid Receptor Binding to the Endothelin-1 Gene (edn1)

Aldosterone Modulates Steroid Receptor Binding to the Endothelin-1 Gene (edn1)

Steroid hormones modulate H19 gene expression in both mammary gland and uterus

Allosteric Effects of Dexamethasone and RU486 on Glucocorticoid Receptor-DNA Interactions

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