scholarly journals Creation of Estrogen Resistance in Vivo by Transgenic Overexpression of the Heterogeneous Nuclear Ribonucleoprotein-Related Estrogen Response Element Binding Protein

Endocrinology ◽  
2005 ◽  
Vol 146 (10) ◽  
pp. 4266-4273 ◽  
Author(s):  
Hong Chen ◽  
William Stuart ◽  
Bing Hu ◽  
Lisa Nguyen ◽  
Ganghua Huang ◽  
...  
Keyword(s):  
Transgenic Mice ◽  
Binding Protein ◽  
Primate Species ◽  
Target Cells ◽  
Estrogen Response Element ◽  
Response Element ◽  
Heterogeneous Nuclear Ribonucleoprotein ◽  
Estrogen Response ◽  
Nuclear Ribonucleoprotein

Estrogen unresponsiveness among primate species can result from overexpression of a heterogeneous nuclear ribonucleoprotein (hnRNP) that competes with estrogen receptor (ER) for binding to the estrogen-response element (ERE). This hnRNP has been coined the “ERE-binding protein” (ERE-BP). The ERE-BP is a member of the hnRNP C-like subfamily of hnRNPs, traditionally considered to be single-strand RNA binding proteins designed for the stabilization and handling of pre-mRNA. To verify in vivo the dominant-negative actions of the ERE-BP to inhibit ER-ERE-directed transactivation and to avoid the potential for lethality from global overexpression of an hnRNP, we generated transgenic mice that overexpressed ERE-BP in breast tissue under the control of a whey acidic protein gene promoter. Graded overexpression of ERE-BP in transgenic mice was established. Founders were viable and fertile. Female transgenics in all lines gave birth to pups, but their ability to nurse was dependent on the level of ERE-BP expression in breast; high-ERE-BP expressors were unable to lactate. A gradient of impaired breast pheno(histo)type, from near normal to failed ductal development and lactational capacity, correlated with the relative level of transgene expression. ERE-BP, expressed either endogenously as a transgene or after transfection, colocalized with ERα in the nucleus of target cells. This work confirms that tissue-targeted overexpression of the ERE-BP can effectively block estrogen-ERα-ERE-directed action in vivo.

scholarly journals Estradiol and Tamoxifen Mediate Rescue of the Dominant-Negative Effects of Estrogen Response Element-Binding Protein in Vivo and in Vitro

Endocrinology ◽  
2008 ◽  
Vol 150 (5) ◽  
pp. 2429-2435 ◽  
Author(s):  
Hong Chen ◽  
Thomas L. Clemens ◽  
Martin Hewison ◽  
John S. Adams
Keyword(s):  
Estrogen Receptor ◽  
Transgenic Mice ◽  
Binding Protein ◽  
Fold Increase ◽  
Estrogen Response Element ◽  
Wild Type ◽  
Branch Number ◽  
Response Element ◽  
Estrogen Response

Biological responses to estrogens are dependent on the integrated actions of proteins, including the estrogen receptor (ER)-α, that regulate the transcription of estrogen response element (ERE)-containing target genes. We have identified a naturally occurring ERE antagonist, termed an ERE-binding protein (BP). To verify that ERE-BP can induce estradiol (E2) resistance in vivo, we generated transgenic mice that overexpress this protein in breast tissue. Female transgenic mice with high levels of ERE-BP were unable to lactate, and we hypothesized that this effect was dependent on the relative levels of ERE-BP and ERα ligand. To test this hypothesis, wild-type and ERE-BP-expressing female mice were implanted with capsules containing E2, the selective estrogen receptor modulator tamoxifen, or placebo. Histological analysis of nonlactating mammary glands showed a 4.5-fold increase in gland branch number and 3.7-fold increase in ducts in ERE-BP mice treated with E2 (7.5 mg, 21 d) compared with placebo-treated ERE-BP mice. Wild-type mice showed a 5.3-fold increase in branches and 1.4-fold increase in ducts under the same conditions. Similar results were obtained with tissue from lactating mice, in which tamoxifen also increased mammary gland branch number. Studies using ERE-BP-expressing MCF-7 breast cells showed that high doses of E2 (1000 nm) restored normal ERα-chromatin interaction in these cells, whereas tamoxifen was able to achieve this effect at a dose of 10 nm. These data highlight the importance of ERE-BP as an attenuator of normal ERα signaling in vivo and further suggest that ERE-BP is a novel target for modulation by selective estrogen receptor modulators.

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 Multiple single-stranded cis elements are associated with activated chromatin of the human c-myc gene in vivo.

1996 ◽  
Vol 16 (6) ◽  
pp. 2656-2669 ◽  
Author(s):  
G A Michelotti ◽  
E F Michelotti ◽  
A Pullner ◽  
R C Duncan ◽  
D Eick ◽  
...  
Keyword(s):  
Binding Protein ◽  
Single Strand ◽  
Upstream Sequence ◽  
Cis Elements ◽  
Sequence Element ◽  
S1 Nuclease ◽  
Heterogeneous Nuclear Ribonucleoprotein ◽  
Myc Gene ◽  
Nuclear Ribonucleoprotein

Transcription activation and repression of eukaryotic genes are associated with conformational and topological changes of the DNA and chromatin, altering the spectrum of proteins associated with an active gene. Segments of the human c-myc gene possessing non-B structure in vivo located with enzymatic and chemical probes. Sites hypertensive to cleavage with single-strand-specific S1 nuclease or the single-strand-selective agent potassium permanganate included the major promoters P1 and P2 as well as the far upstream sequence element (FUSE) and CT elements, which bind, respectively, the single-strand-specific factors FUSE-binding protein and heterogeneous nuclear ribonucleoprotein K in vitro. Active and inactive c-myc genes yielded different patterns of S1 nuclease and permanganate sensitivity, indicating alternative chromatin configurations of active and silent genes. The melting of specific cis elements of active c-myc genes in vivo suggested that transcriptionally associated torsional strain might assist strand separation and facilitate factor binding. Therefore, the interaction of FUSE-binding protein and heterogeneous nuclear ribonucleoprotein K with supercoiled DNA was studied. Remarkably, both proteins recognize their respective elements torsionally strained but not as liner duplexes. Single-strand- or supercoil-dependent gene regulatory proteins may directly link alterations in DNA conformation and topology with changes in gene expression.

scholarly journals Heterogeneous Nuclear Ribonucleoprotein (hnRNP) E1 Binds to hnRNP A2 and Inhibits Translation of A2 Response Element mRNAs

2006 ◽  
Vol 17 (8) ◽  
pp. 3521-3533 ◽  
Author(s):  
Linda D. Kosturko ◽  
Michael J. Maggipinto ◽  
George Korza ◽  
Joo Won Lee ◽  
John H. Carson ◽  
...  
Keyword(s):  
Rna Binding ◽  
Binding Protein ◽  
Rna Binding Protein ◽  
In Vitro Translation ◽  
Dependent Manner ◽  
Response Element ◽  
Heterogeneous Nuclear Ribonucleoprotein ◽  
Nuclear Ribonucleoprotein ◽  
Hnrnp E1

Heterogeneous nuclear ribonucleoprotein (hnRNP) A2 is a trans-acting RNA-binding protein that mediates trafficking of RNAs containing the cis-acting A2 response element (A2RE). Previous work has shown that A2RE RNAs are transported to myelin in oligodendrocytes and to dendrites in neurons. hnRNP E1 is an RNA-binding protein that regulates translation of specific mRNAs. Here, we show by yeast two-hybrid analysis, in vivo and in vitro coimmunoprecipitation, in vitro cross-linking, and fluorescence correlation spectroscopy that hnRNP E1 binds to hnRNP A2 and is recruited to A2RE RNA in an hnRNP A2-dependent manner. hnRNP E1 is colocalized with hnRNP A2 and A2RE mRNA in granules in dendrites of oligodendrocytes. Overexpression of hnRNP E1 or microinjection of exogenous hnRNP E1 in neural cells inhibits translation of A2RE mRNA, but not of non-A2RE RNA. Excess hnRNP E1 added to an in vitro translation system reduces translation efficiency of A2RE mRNA, but not of nonA2RE RNA, in an hnRNP A2-dependent manner. These results are consistent with a model where hnRNP E1 recruited to A2RE RNA granules by binding to hnRNP A2 inhibits translation of A2RE RNA during granule transport.

scholarly journals Heterogeneous nuclear ribonucleoprotein D0B is a sequence-specificDNA-binding protein

1999 ◽  
Vol 338 (2) ◽  
pp. 417-425 ◽  
Author(s):  
Mate TOLNAY ◽  
Lyudmila A. VERESHCHAGINA ◽  
George C. TSOKOS
Keyword(s):  
Dna Sequences ◽  
Rna Binding ◽  
Binding Protein ◽  
Double Helix ◽  
Physiological Role ◽  
Single Stranded Dna ◽  
Heterogeneous Nuclear Ribonucleoprotein ◽  
Double Stranded Dna ◽  
Nuclear Ribonucleoprotein

Complement receptor 2 (CR2) is important in the regulation of the B lymphocyte response; the regulation of its expression is therefore of central importance. We recently reported that a 42 kDa heterogeneous nuclear ribonucleoprotein (hnRNP) is involved in the transcriptional regulation of the human CR2 gene [Tolnay, Lambris and Tsokos (1997) J. Immunol. 159, 5492–5501]. We cloned the cDNA encoding this protein and found it to be identical with hnRNP D0B, a sequence-specific RNA-binding protein. By using a set of mutated oligonucleotides, we demonstrated that the recombinant hnRNP D0B displays sequence specificity for double-stranded oligonucleotide defined by the CR2 promoter. We conducted electrophoretic mobility-shift assays to estimate the apparent Kd of hnRNP D0B for the double-stranded DNA motif and found it to be 59 nM. Interestingly, hnRNP D0B displayed affinities of 28 and 18 nM for the sense and anti-sense strands of the CR2 promoter-defined oligonucleotide respectively. The significantly greater binding affinity of hnRNP D0B for single-stranded DNA than for double-stranded DNA suggests that the protein might melt the double helix. The intranuclear concentration of sequence-specific protein was estimated to be 250–400 nM, indicating that the protein binds to the CR2 promoter in vivo. Co-precipitation of a complex formed in vivo between hnRNP D0B and the TATA-binding protein demonstrates that hnRNP D0B interacts with the basal transcription apparatus. Our results suggest a new physiological role for hnRNP D0B that involves binding to double- and single-stranded DNA sequences in a specific manner and functioning as a transcription factor.

scholarly journals A new regulator of osteoclastogenesis: Estrogen response element-binding protein in bone

2011 ◽  
Vol 26 (10) ◽  
pp. 2537-2547 ◽  
Author(s):  
Hong Chen ◽  
Linda C Gilbert ◽  
X Lu ◽  
Zhaofan Liu ◽  
Shaojin You ◽  
...  
Keyword(s):  
Binding Protein ◽  
Estrogen Response Element ◽  
Response Element ◽  
Estrogen Response ◽  
Element Binding Protein

scholarly journals Prenylflavonoid Icariin Induces Estrogen Response Element–Independent Estrogenic Responses in a Tissue-Selective Manner

2019 ◽  
Vol 4 (2) ◽  
Author(s):  
Liping Zhou ◽  
Christina Chui-Wa Poon ◽  
Ka-Ying Wong ◽  
Sisi Cao ◽  
Wenxuan Yu ◽  
...  
Keyword(s):  
Bone Structure ◽  
Estrogen Response Element ◽  
Mineral Density ◽  
Response Element ◽  
Estrogenic Effects ◽  
Estrogen Response ◽  
Ovx Rats ◽  
Long Term Treatment

Abstract Icariin, a flavonoid phytoestrogen derived from Herba epimedii, has been reported to exert estrogenic effects in bone and activate phosphorylation of estrogen receptor (ER) α in osteoblastic cells. However, it is unclear whether icariin selectively exerts estrogenic activities in bone without inducing undesirable effects in other estrogen-sensitive tissues. The present study aimed to investigate the tissue-selective estrogenic activities of icariin in estrogen-sensitive tissues in vivo and in vitro. Long-term treatment with icariin effectively prevented bone of ovariectomized (OVX) rats from estrogen deficiency–induced osteoporotic changes in bone structure, bone mineral density, and trabecular properties. Moreover, icariin regulated the transcriptional events of estrogen-responsive genes related to bone remodeling and prevented dopaminergic neurons against OVX-induced changes by rescuing expression of estrogen-regulated tyrosine hydroxylase and dopamine transporter in the striatum. Unlike estrogen, icariin did not induce estrogenic effects in the uterus and breast in mature OVX rats or immature CD-1 mice. In vitro studies demonstrated that icariin exerted estrogen-like activities and regulated the expression of estrogen-responsive genes but did not induce estrogen response element–dependent luciferase activities in ER-positive cells. Our results support the hypothesis that icariin, through its distinct mechanism of actions in activating ER, selectively exerts estrogenic activities in different tissues and cell types.

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