In vitro interaction of uterine estrogen receptor with the estrogen response element present in the 3′-flanking region of the murine c-fos protooncogene

Author(s):  
Salman M. Hyder ◽  
George M. Stancel
2005 ◽  
Vol 19 (11) ◽  
pp. 2696-2712 ◽  
Author(s):  
Jing Huang ◽  
Xiaodong Li ◽  
Casey A. Maguire ◽  
Russell Hilf ◽  
Robert A. Bambara ◽  
...  

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.


2004 ◽  
Vol 18 (11) ◽  
pp. 2649-2659 ◽  
Author(s):  
Margaret A. Loven ◽  
Roger E. Davis ◽  
Carol D. Curtis ◽  
Nemone Muster ◽  
John R. Yates ◽  
...  

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.


1997 ◽  
Vol 11 (10) ◽  
pp. 1486-1496 ◽  
Author(s):  
Katarina Pettersson ◽  
Kaj Grandien ◽  
George G. J. M. Kuiper ◽  
Jan-Åke Gustafsson

Physiology ◽  
2016 ◽  
Vol 31 (4) ◽  
pp. 258-269 ◽  
Author(s):  
Jennifer Blakemore ◽  
Fredrick Naftolin

Aromatase (estrogen synthetase; EC 1.14.14.1) catalyzes the demethylation of androgens' carbon 19, producing phenolic 18-carbon estrogens. Aromatase is most widely known for its roles in reproduction and reproductive system diseases, and as a target for inhibitor therapy in estrogen-sensitive diseases including cancer, endometriosis, and leiomyoma (141, 143). However, all tissues contain estrogen receptor-expressing cells, the majority of genes have a complete or partial estrogen response element that regulates their expression (61), and there are plentiful nonreceptor effects of estrogens (79); therefore, the effect of aromatase through the provision of estrogen is almost universal in terms of health and disease. This review will provide a brief but comprehensive overview of the enzyme, its role in steroidogenesis, the problems that arise with its functional mutations and mishaps, the roles in human physiology of aromatase and its product estrogens, its current clinical roles, and the effects of aromatase inhibitors. While much of the story is that of the consequences of the formation of its product estrogens, we also will address alternative enzymatic roles of aromatase as a demethylase or nonenzymatic actions of this versatile molecule. Although this short review is meant to be thorough, it is by no means exhaustive; rather, it is meant to reflect the cutting-edge, exciting properties and possibilities of this ancient enzyme and its products.


1998 ◽  
Vol 12 (5) ◽  
pp. 664-674 ◽  
Author(s):  
Lorene E. Romine ◽  
Jennifer R. Wood ◽  
LuAnne A. Lamia ◽  
Paul Prendergast ◽  
Dean P. Edwards ◽  
...  

Abstract We have examined the ability of the high-mobility group protein 1 (HMG1) to alter binding of the estrogen receptor DNA-binding domain (DBD) to the estrogen response element (ERE). HMG1 dramatically enhanced binding of purified, bacterially expressed DBD to the consensus vitellogenin A2 ERE in a dose-dependent manner. The ability of HMG1 to stabilize the DBD-ERE complex resulted in part from a decrease in the dissociation rate of the DBD from the ERE. Antibody supershift experiments demonstrated that HMG1 was also capable of forming a ternary complex with the ERE-bound DBD in the presence of HMG1-specific antibody. HMG1 did not substantially affect DBD-ERE contacts as assessed by methylation interference assays, nor did it alter the ability of the DBD to induce distortion in ERE-containing DNA fragments. Because HMG1 dramatically enhanced estrogen receptor DBD binding to the ERE, and the DBD is the most highly conserved region among the nuclear receptor superfamily members, HMG1 may function to enhance binding of other nuclear receptors to their respective response elements and act in concert with coactivator proteins to regulate expression of hormone-responsive genes.


2007 ◽  
Vol 292 (2) ◽  
pp. E435-E442 ◽  
Author(s):  
G. Eda Akbas ◽  
Xiaolan Fei ◽  
Hugh S. Taylor

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.


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