scholarly journals Estradiol Reduces Nonclassical Transcription at Cyclic Adenosine 3′,5′-Monophosphate Response Elements in Glioma Cells Expressing Estrogen Receptor Alpha

Endocrinology ◽  
2006 ◽  
Vol 147 (4) ◽  
pp. 1796-1804 ◽  
Author(s):  
Andrew J. Mhyre ◽  
Robert A. Shapiro ◽  
Daniel M. Dorsa
Keyword(s):  
Gene Expression ◽  
Estrogen Receptor ◽  
Reporter Gene ◽  
Glioma Cells ◽  
Luciferase Reporter ◽  
Estradiol Treatment ◽  
Camp Response Element ◽  
Response Element ◽  
Functional Changes ◽  
Rapid Signaling

Estradiol can protect the brain from a variety of insults by activating membrane-initiated signaling pathways, and thereby modulate gene expression and lead to functional changes in neurons. These direct neuronal effects of the hormone have been well documented; however, it is less understood what effects estradiol may have on nonneuronal cells of the central nervous system. There is evidence that estradiol levels can induce the release of glial-derived growth factors and other cytokines, suggesting that estradiol may both directly and indirectly protect neurons. To determine whether 17β-estradiol (E2) can activate rapid signaling and modulate nonclassical transcription in astrocytes, we stably transfected the C6 rat glioblastoma cell line with human estrogen receptor (ER) α (C6ERα) or rat ERβ (C6ERβ). Introduction of a cAMP response element-luciferase reporter gene into C6, C6ERα, and C6ERβ cells leads to the observation that E2 treatment reduced isoproterenol-stimulated luciferase activity by 35% in C6ERα but had no effect on reporter gene expression in C6ERβ or untransfected C6 cells. A similar effect was seen with a membrane-impermeable estrogen (E2-BSA), suggesting the modulation of nonclassical transcription by estradiol treatment is mediated by the activation of a membrane-initiated signaling pathway. Furthermore, pretreatment with wortmannin (phosphatidylinsositol 3-kinase) or U73122 (phospholipase C) attenuated the E2-induced reduction in nonclassical transcription. We conclude that E2 treatment reduces cAMP response element-mediated transcription in glioma cells expressing ERα and that this reduction is dependent on the activation of membrane-initiated signaling. These findings suggest a novel model of estrogen rapid signaling in astrocytes that leads to modulation of nonclassical transcription.

scholarly journals Identification of a cAMP response element within the glucose- 6-phosphatase hydrolytic subunit gene promoter which is involved in the transcriptional regulation by cAMP and glucocorticoids in H4IIE hepatoma cells

1999 ◽  
Vol 338 (2) ◽  
pp. 457-463 ◽  
Author(s):  
Dieter SCHMOLL ◽  
Christina WASNER ◽  
Carolyn J. HINDS ◽  
Bernard B. ALLAN ◽  
Reinhard WALTHER ◽  
...  
Keyword(s):  
Reporter Gene ◽  
Consensus Sequence ◽  
Gene Promoter ◽  
Hepatoma Cells ◽  
Luciferase Reporter ◽  
Regulation Of Transcription ◽  
Dibutyryl Camp ◽  
Luciferase Reporter Gene ◽  
Camp Response Element ◽  
Response Element

The expression of a luciferase reporter gene under the control of the human glucose 6-phosphatase gene promoter was stimulated by both dexamethasone and dibutyryl cAMP in H4IIE hepatoma cells. A cis-active element located between nucleotides -161 and -152 in the glucose 6-phosphatase gene promoter was identified and found to be necessary for both basal reporter-gene expression and induction of expression by both dibutyryl cAMP and dexamethasone. Nucleotides -161 to -152 were functionally replaced by the consensus sequence for a cAMP response element. An antibody against the cAMP response element-binding protein caused a supershift in gel-electrophoretic-mobility-shift assays using an oligonucleotide probe representing the glucose 6-phosphatase gene promoter from nucleotides -161 to -152. These results strongly indicate that in H4IIE cells the glucose 6-phosphatase gene-promoter sequence from -161 to -152 is a cAMP response element which is important for the regulation of transcription of the glucose 6-phosphatase gene by both cAMP and glucocorticoids.

scholarly journals The Rho effector, PKN, regulates ANF gene transcription in cardiomyocytes through a serum response element

2000 ◽  
Vol 278 (6) ◽  
pp. H1769-H1774 ◽  
Author(s):  
Michael R. Morissette ◽  
Valerie P. Sah ◽  
Christopher C. Glembotski ◽  
Joan Heller Brown
Keyword(s):  
Gene Expression ◽  
Reporter Gene ◽  
Dominant Negative ◽  
Neonatal Rat ◽  
Common Element ◽  
Luciferase Reporter ◽  
Serum Response Element ◽  
Transcriptional Responses ◽  
Response Element ◽  
Serum Response

The low-molecular-weight GTP-binding protein RhoA mediates hypertrophic growth and atrial natriuretic factor (ANF) gene expression in neonatal rat ventricular myocytes. Neither the effector nor the promoter elements through which Rho exerts its regulatory effects on ANF gene expression have been elucidated. When constitutively activated forms of Rho kinase and two protein kinase C-related kinases, PKN (PRK1) and PRK2, were compared, only PKN generated a robust stimulation of a luciferase reporter gene driven by a 638-bp fragment on the ANF promoter. This ANF promoter fragment contains a proximal serum response element (SRE) and an Sp-1-like element required for the transcriptional response to phenylephrine (PE). This response was inhibited by dominant negative Rho. The ability of dominant negative Rho to inhibit the response to PE and the ability of PKN to stimulate ANF reporter gene expression were both lost when the SRE was mutated. Mutation of the Sp-1-like element also attenuated the response to PKN. A minimal promoter driven by ANF SRE sequences was sufficient to confer Rho- and PKN-mediated gene expression. Interestingly, PKN preferentially stimulated the ANF versus the c- fos SRE reporter gene. Thus PKN and Rho are able to regulate transcriptional activation of the ANF SRE by a common element that could implicate PKN as a downstream effector of Rho in transcriptional responses associated with hypertrophy.

scholarly journals Estrogen receptor regulates insulin-like growth factor-I receptor gene expression in breast tumor cells: involvement of transcription factor Sp1

2006 ◽  
Vol 191 (3) ◽  
pp. 605-612 ◽  
Author(s):  
Sharon Maor ◽  
Doris Mayer ◽  
Ronit I Yarden ◽  
Adrian V Lee ◽  
Rive Sarfstein ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Gene Expression ◽  
Estrogen Receptor ◽  
Transcription Factor ◽  
Receptor Gene ◽  
Luciferase Reporter ◽  
Cancer Etiology ◽  
Estradiol Treatment ◽  
Igf I ◽  
Mcf 7

The insulin-like growth factors, IGF-I and IGF-II are a familyof mitogenic polypeptides with important roles in growth and differentiation. The biological actions of the IGFs are mediated by the IGF-I receptor (IGF-IR), a cell-surface tyrosine kinase, whose activation by serum IGF-I seems to be a key step in breast cancer initiation. Evidence accumulated indicates that estrogens stimulate the expression and activity of IGF axis components. The aim of our study was to examine the transcriptional mechanisms involved in regulation of IGF-IR gene expression by the estrogen receptor (ER). For this purpose, transient transfections using an IGF-IR promoter-luciferase reporter plasmid were performed in breast cancer-c derived ER-positive MCF-7 cells and isogenic ER-negative C4 cells. To examine the potential involvement of zinc-finger nuclear proteins in the transactivating effect of estrogens, chromatin immunoprecipitation (ChIP) experiments were performed using an Sp1 antibody, along with the Sp1-family-binding inhibitor Mithramycin A. The results obtained indicate that basal IGF-IR promoter activity was 5.8-fold higher in MCF-7 than in C4 cells. Estradiol treatment significantly activated the IGF-IR promoter in MCF-7, but not in C4 cells. Furthermore, the estrogen responsive region in the IGF-IR promoter was mapped to a GC-rich sequence located between nucleotides −40 and −188 in the 5′ flanking region. ChIP experiments revealed that at least part of the estrogen effect on IGF-IR expression was mediated through activation of the Sp1 transcription factor. In summary, our studies demonstrate that IGF-IR gene transcription in breast cancer cells is controlled by interactions between ERα and Sp1. Dysregulated expression of the IGF-IR gene may have pathologic consequences with relevance in breast cancer etiology.

Abstract 117: MicroRNA-138 regulates S100A1 in Endothelial Cells

2013 ◽  
Vol 113 (suppl_1) ◽  
Author(s):  
Anagha Sen ◽  
Shumei Ren ◽  
Jianxin Sun ◽  
Patrick Most ◽  
Karsten Peppel
Keyword(s):  
Gene Expression ◽  
Endothelial Cells ◽  
Reporter Gene ◽  
Recombinant Adenovirus ◽  
Limb Ischemia ◽  
Bioinformatic Analysis ◽  
Reporter Gene Expression ◽  
Luciferase Reporter ◽  
C2c12 Myotubes ◽  
Luciferase Reporter Construct

Rationale: The EF-hand Ca2+ sensor S100A1 is essential for proper endothelial nitric oxide (NO) synthase (eNOS) activation. S100A1 levels are greatly reduced in endothelial cells (ECs) subjected to hypoxia, rendering them dysfunctional. Objective: To determine if the 3’UTR mediates the rapid hypoxia-induced downregulation of S100A1 in ECs. Methods and Results: ECs transfected with a S100A1 - 3’ untranslated region (UTR) luciferase reporter construct displayed significantly reduced gene expression when subjected to gas or chemical hypoxia. Bioinformatic analysis suggested that microRNA -138 (miR-138) could target the 3’UTR of S100A1. Hypoxia greatly increased miR-138 levels in ECs, but not in skeletal muscle C2C12 myotubes. Consistent with this finding, patients with critical limb ischemia (CLI) or mice subjected to femoral artery resection (FAR) displayed increased miR-138 levels. Transfection of a miR-138 mimic into ECs reduced S100A1 - 3 ‘UTR reporter gene expression, while transfection of an anti miR-138 (antagomir) prevented the hypoxia-induced downregulation of the reporter gene. The increased levels of miR-138 are dependent on Hif1-α activation as treatment with siRNA against Hif1-α prevented S100A1 reporter gene downregulation after hypoxia. Conversely, specific activation of Hif1-α by a selective prolyl-hydroxylase inhibitor (IOX2) reduced reporter gene expression. Finally, ECs transfected with miR-138 mimic displayed reduced tube formation when plated onto Matrigel matrix and expressed less NO when stimulated with VEGF. These effects were reversed by gene transfer of S100A1 using recombinant adenovirus. Conclusions: Our study shows that miR-138 is an essential mediator of EC dysfunction via its ability to target the 3’UTR of S100A1 in a hypoxia-induced manner. MiR-138 might thus be an attractive target for the treatment of pathologies that are linked to endothelial dysfunction.

Potency of isothiocyanates to induce luciferase reporter gene expression via the electrophile-responsive element from murine glutathione S-transferase Ya

2009 ◽  
Vol 23 (4) ◽  
pp. 617-621 ◽  
Author(s):  
Martijn Vermeulen ◽  
Anne-Marie M.J.F. Boerboom ◽  
Barry M.G. Blankvoort ◽  
Jac M.M.J.G. Aarts ◽  
Ivonne M.C.M. Rietjens ◽  
...  
Keyword(s):  
Gene Expression ◽  
Reporter Gene ◽  
Reporter Gene Expression ◽  
Luciferase Reporter ◽  
Glutathione S Transferase ◽  
Luciferase Reporter Gene ◽  
Responsive Element
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