scholarly journals A Novel Estrogen Receptor α-Associated Protein Alters Receptor-Deoxyribonucleic Acid Interactions and Represses Receptor-Mediated Transcription

2004 ◽  
Vol 18 (11) ◽  
pp. 2649-2659 ◽  
Author(s):  
Margaret A. Loven ◽  
Roger E. Davis ◽  
Carol D. Curtis ◽  
Nemone Muster ◽  
John R. Yates ◽  
...  
Keyword(s):  
Estrogen Receptor ◽  
Thyroid Hormone Receptor ◽  
Estrogen Receptor Α ◽  
Target Cells ◽  
Estrogen Response Element ◽  
Response Element ◽  
Estrogen Response ◽  
Mcf 7

Abstract Estrogen receptor α (ERα) serves as a ligand-activated transcription factor, turning on transcription of estrogen-responsive genes in target cells. Numerous regulatory proteins interact with the receptor to influence ERα-mediated transactivation. In this study, we have identified pp32, which interacts with the DNA binding domain of ERα when the receptor is free, but not when it is bound to an estrogen response element. Coimmunoprecipitation experiments demonstrate that endogenously expressed pp32 and ERα from MCF-7 breast cancer cells interact. Although pp32 substantially enhances the association of the receptor with estrogen response element-containing DNA, overexpression of pp32 in MCF-7 cells decreases transcription of an estrogen-responsive reporter plasmid. pp32 Represses p300-mediated acetylation of ERα and histones in vitro and inhibits acetylation of ERα in vivo. pp32 Also binds to other nuclear receptors and inhibits thyroid hormone receptor β-mediated transcription. Taken together, our studies provide evidence that pp32 plays a role in regulating transcription of estrogen-responsive genes by modulating acetylation of histones and ERα and also influences transcription of other hormone-responsive genes as well.

scholarly journals Mouse Estrogen Receptor β Forms Estrogen Response Element-Binding Heterodimers with Estrogen Receptor α

1997 ◽  
Vol 11 (10) ◽  
pp. 1486-1496 ◽  
Author(s):  
Katarina Pettersson ◽  
Kaj Grandien ◽  
George G. J. M. Kuiper ◽  
Jan-Åke Gustafsson
Keyword(s):  
Estrogen Receptor ◽  
Estrogen Receptor Α ◽  
Estrogen Receptor Β ◽  
Estrogen Response Element ◽  
Response Element ◽  
Estrogen Response

Regulation of HOXA10 expression by phytoestrogens

2007 ◽  
Vol 292 (2) ◽  
pp. E435-E442 ◽  
Author(s):  
G. Eda Akbas ◽  
Xiaolan Fei ◽  
Hugh S. Taylor
Keyword(s):  
Estrogen Receptor ◽  
Estrogen Receptor Α ◽  
In Utero ◽  
Estrogen Response Element ◽  
Mouse Uterus ◽  
Response Element ◽  
Estrogen Response ◽  
Uterine Anomalies ◽  
Mrna And Protein Expression ◽  
Adult Exposure

HOXA10 is necessary for normal development of the Müllerian duct, and continued adult expression in the uterus is necessary for female fertility. HOXA10 expression is altered by diethylstilbestrol, leading to uterine anomalies. Other endocrine disruptors may potentially lead to reproductive anomalies or dysfunction by altering HOXA10 expression. Here we investigated the effect of isoflavones on HOXA10 expression after in utero or adult exposure in the mouse. Genistein, but not diadzein, regulated HOXA10 mRNA and protein expression in the adult mouse uterus. In contrast, in utero genistein or diadzein exposure had no lasting effect on HOXA10 expression in the exposed offspring. Reporter gene expression driven by the HOXA10 estrogen response element was increased in a dose-responsive manner by genistein, but not daidzein. Neither estrogen receptor-α nor estrogen receptor-β binding to the HOXA10 estrogen response element was affected by genistein or daidzein. In utero exposure to isoflavones is unlikely to result in HOXA10-mediated developmental anomalies. Adult genistein exposure alters uterine HOXA10 expression, a potential mechanism by which this agent affects fertility.

scholarly journals Binding of Estrogen Receptor β to Estrogen Response Element in Situ Is Independent of Estradiol and Impaired by Its Amino Terminus

2005 ◽  
Vol 19 (11) ◽  
pp. 2696-2712 ◽  
Author(s):  
Jing Huang ◽  
Xiaodong Li ◽  
Casey A. Maguire ◽  
Russell Hilf ◽  
Robert A. Bambara ◽  
...  
Keyword(s):  
Estrogen Receptor ◽  
Activation Function ◽  
Amino Terminus ◽  
Estrogen Response Element ◽  
Response Element ◽  
Estrogen Response ◽  
17Β Estradiol ◽  
Additional Explanation

Abstract The functions of 17β-estradiol (E2) are mediated by estrogen receptor (ER) α and β. ERs display similar DNA- and ligand-binding properties in vitro. However, ERβ shows lower transcriptional activity than ERα from the estrogen response element (ERE)-dependent signaling. We predicted that distinct amino termini contribute to differences in transcription efficacies of ERs by affecting in situ ER-ERE interactions. We used chromatin immunoprecipitation and a novel in situ ERE competition assay, which is based on the ability of ER to compete for ERE binding with a designer activator that constitutively induces transcription from an ERE-driven reporter construct. Interference of activator-mediated transcription by unliganded or liganded ERs was taken as an indication of ER-ERE interaction. Results revealed that ERs interacted with ERE similarly in the absence of E2. However, E2 enhanced the ERE binding of ERα but not that of ERβ. The removal of the amino terminus increased the ERβ-ERE interaction independent of E2. The ERβ amino terminus also prevented E2-mediated enhancement of the chimeric ERα-ERE interaction. Thus, the amino terminus of ERβ impairs the binding of ERβ to ERE. The abrogation of ligand-dependent activation function 2 of the amino-terminally truncated ERβ resulted in the manifestation of E2 effect on ERβ-ERE interaction. This implies that E2-mediated enhancement of ERβ-ERE interaction is masked by the activation function 2, whereas the intact amino terminus is a dominant region that decreases the binding of ERβ to ERE. Thus, ERβ-ERE interaction is independent of E2 and is impaired by its amino terminus. These findings provide an additional explanation for differences between ERα and ERβ functions that could differentially affect the physiology and pathophysiology of E2 signaling.

scholarly journals A Functional Serine 118 Phosphorylation Site in Estrogen Receptor-α Is Required for Down-Regulation of Gene Expression by 17β-Estradiol and 4-Hydroxytamoxifen

Endocrinology ◽  
2007 ◽  
Vol 148 (10) ◽  
pp. 4634-4641 ◽  
Author(s):  
Jingwei Cheng ◽  
Chen Zhang ◽  
David J. Shapiro
Keyword(s):  
Estrogen Receptor ◽  
Regulation Of Gene Expression ◽  
Phosphorylation Site ◽  
Estrogen Receptor Α ◽  
Estrogen Response Element ◽  
Down Regulation ◽  
Response Element ◽  
Estrogen Response ◽  
Endogenous Genes ◽  
17Β Estradiol

To evaluate the contribution of ERK1/2 phosphorylation of estrogen receptor (ER)-α to activation and repression of endogenous genes, we produced stably transfected lines of HeLa cells with functional ERK1/2 pathways that express similar levels of wild-type human ERα and ERα mutated to inactivate the well-known MAPK site at serine 118 (ERαS118A). We compared effects of the S118A mutation on 17β-estradiol (E2)-mediated transactivation, which is heavily dependent on activation function (AF) 2 of ERα and on 4-hydroxytamoxifen (OHT)-mediated transactivation, which is heavily dependent on AF1, which includes S118. To examine whether S118 was the key ERK/MAPK phosphorylation site in ERα action, we compared the effects of the S118A mutant and the ERK inhibitor U0126 on expression of endogenous genes. In several estrogen response element-containing genes, the S118A mutation strongly reduced induction by E2, and U0126 did not further reduce expression. Expression of another group of estrogen response element-containing genes was largely unaffected by the S118A mutation. The S118A mutation had variable effects on genes induced by ER tethering or binding near specificity protein-1 and activator protein-1 sites. For five mRNAs whose expression is strongly down-regulated by E2 and partially or completely down-regulated by OHT, the S118A mutation reduced or abolished down-regulation by E2 and nearly abolished down-regulation by OHT. In contrast, for Sma and mothers against decapentaplegic-3-related, which is down-regulated by E2 and not OHT, the S118A mutation had little effect. These data suggest that there may be distinct groups of genes down-regulated by ERα and suggest a novel role for ERK phosphorylation at serine 118 in AF1 in regulating expression of the set of genes down-regulated by OHT.

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