scholarly journals Calcium Dynamics and Resting Transcriptional Activity Regulates Prolactin Gene Expression

Endocrinology ◽  
2002 ◽  
Vol 143 (9) ◽  
pp. 3548-3554 ◽  
Author(s):  
Carlos Villalobos ◽  
Lucía Núñez ◽  
William J. Faught ◽  
David C. Leaumont ◽  
Fredric R. Boockfor ◽  
...  
Keyword(s):  
Gene Expression ◽  
Promoter Activity ◽  
Gene Promoter ◽  
Luciferase Reporter ◽  
Pituitary Cells ◽  
Luciferase Reporter Gene ◽  
Transcriptional Responses ◽  
Prolactin Gene ◽  
Before And After ◽  
Single Living

Abstract Research on the regulation of hormone gene expression by calcium signaling is hampered by the difficulty of monitoring both parameters within the same individual, living cells. Here we achieved concurrent, dynamic measurements of both intracellular Ca2+ concentration ([Ca2+]i) and prolactin (PRL) gene promoter activity in single, living pituitary cells. Cells were transfected with the luciferase reporter gene under control of the PRL promoter and subjected to bioluminescence and fluorescence imaging before and after presentation of TSH-releasing hormone (TRH), a prototypic regulator of PRL secretion and gene expression that induces a transient Ca2+ release, followed by sustained Ca2+ influx. We found that cells displaying specific photonic emissions (i.e. mammotropes) showed heterogeneous calcium and transcriptional responses to TRH. Transcriptionally responsive cells always exhibited a TRH-induced [Ca2+]i increase. In addition, transcriptional responses were related to the rate of Ca2+ entry but not Ca2+ release. Finally, cells lacking transcriptional responses (but showing [Ca2+]i rises) exhibited larger levels of resting PRL promoter activity than transcriptionally responsive cells. Thus, our results suggest that the sustained entry of Ca2+ induced by TRH (but not the Ca2+ release) regulates transcriptional responsiveness. Superimposed on this regulation, the previous, resting PRL promoter activity also controls transcriptional responses.

scholarly journals Differential regulation of the TRH gene promoter by triiodothyronine and dexamethasone in pancreatic islets

2001 ◽  
Vol 170 (1) ◽  
pp. 91-98 ◽  
Author(s):  
P Fragner ◽  
SL Lee ◽  
S Aratan de Leon
Keyword(s):  
Gene Expression ◽  
Pancreatic Islets ◽  
Promoter Activity ◽  
Gene Promoter ◽  
Luciferase Reporter ◽  
Flanking Sequence ◽  
Luciferase Reporter Gene ◽  
Neoplastic Cells

TRH was initially found in the hypothalamus and regulates TSH secretion. TRH is also produced by insulin-containing beta-cells. Endogenous TRH positively regulates glucagon secretion and attenuates pancreatic exocrine secretion. We have previously shown that triiodothyronine (T(3)) down-regulates pre-pro-TRH gene expression in vivo and in vitro. The present study was designed to determine the initial impact of T(3) on rat TRH gene promoter and to compare this effect with that of dexamethasone (Dex). Primary islet cells and neoplastic cells (HIT T-15 and RIN m5F) were transiently transfected with fragments of the 5'-flanking sequence of TRH fused to the luciferase reporter gene. The persistence of high TRH concentrations in fetal islets in culture, probably due to transactivating factors, allowed us to explore how T(3) and Dex regulate the TRH promoter activity in transfected cells and whether the hormone effect is dependent on the cell type considered. TRH gene promoter activity is inhibited by T(3) in primary but not neoplastic cells and stimulated by Dex in both primary and neoplastic cells of islets. These findings validate previous in vivo and in vitro studies and indicate the transcriptional impact of these hormones on TRH gene expression in the pancreatic islets.

scholarly journals Real-time imaging of gene promoter activity using an adenoviral reporter construct demonstrates transcriptional dynamics in normal anterior pituitary cells

2003 ◽  
Vol 178 (1) ◽  
pp. 61-69 ◽  
Author(s):  
JA Stirland ◽  
ZC Seymour ◽  
S Windeatt ◽  
AJ Norris ◽  
P Stanley ◽  
...  
Keyword(s):  
Gene Expression ◽  
Real Time ◽  
Cell Lines ◽  
Promoter Activity ◽  
Expression Patterns ◽  
Gene Promoter ◽  
Luciferase Reporter ◽  
Pituitary Cells ◽  
Clonal Cell ◽  
Clonal Cell Lines

Although analysis of luciferase activity using luminescence imaging has provided new insights into the dynamic regulation of gene expression in living tIssues, studies in vitro have relied on stably transfected clonal cell lines, limiting the choice of cell type and species, or DNA microinjection, which is arduous and highly selective. We report here the first use of a recombinant adenovirus in which the firefly luciferase reporter gene was regulated by the prolactin gene promoter, to study temporal dynamics of promoter activity. This vector was used to infect the pituitary GH3 cell line, and also primary cultures of Syrian hamster pituitary cells. We show that adenovirally transduced cells retained normal regulation of the promoter-reporter transgene by appropriate signals. Furthermore, microscopic imaging studies indicated that both clonal and primary pituitary cells were transduced efficiently, giving readily detectable luminescence signals in real-time over long periods. Finally, analysis of single-cell expression patterns indicated that prolactin promoter activity was highly dynamic with pulses in gene expression, revealing that the transcriptional instability seen in clonal cells is a feature of normal pituitary cells. Adenoviral vectors offer a valuable tool for studies of gene regulation where conventional transgenesis and clonal cell lines are not available.

scholarly journals Pulses of Prolactin Promoter Activity Depend on a Noncanonical E-Box that Can Bind the Circadian Proteins CLOCK and BMAL1

Endocrinology ◽  
2005 ◽  
Vol 146 (6) ◽  
pp. 2782-2790 ◽  
Author(s):  
Gilles M. Leclerc ◽  
Fredric R. Boockfor
Keyword(s):  
Promoter Activity ◽  
Clock Genes ◽  
Single Cells ◽  
Luciferase Reporter ◽  
Luciferase Reporter Gene ◽  
Prolactin Gene ◽  
E Box ◽  
E Boxes ◽  
Single Living

Abstract Recent findings from our laboratory and those of others demonstrated that prolactin gene expression (PRL-GE) oscillates in single living mammotropes, but little information is available on the molecular processes that contribute to this phenomenon. To elucidate the source of this activity, we generated a series of constructs containing decreasing lengths of the PRL promoter fused to a luciferase reporter gene. These constructs were injected into single cells and assayed for photonic activity. We found pulse activity with all plasmids tested, even with the smallest promoter fragment of 331 bp. Sequence analysis of this fragment identified two potential E-boxes (elements known to bind CLOCK and BMAL1 circadian proteins). Furthermore, RT-PCR of PRL cells (pituitary, MMQ, and GH3) revealed expression of clock and bmal1 as well as five other clock genes (per1, per2, cry1, cry2, and tim), suggesting that the circadian system may function in PRL cells. Next, we mutated the core sequences of both E-boxes within the 2.5-kb PRL promoter and found that only mutation of the E-box133 completely abolished PRL-GE pulses. EMSAs revealed that CLOCK and BMAL1 were able to bind to the E-box133 site in vitro. Our results demonstrate that PRL-GE pulses are dependent on a specific E-box binding site in the PRL promoter. Moreover, the indication that CLOCK/BMAL1 can bind to this site suggests that these circadian proteins, either alone or in conjunction with other factors, may regulate intermittent PRL promoter activity in mammotropes, perhaps by acting as a temporal switch for the on/off expression of PRL.

Phospholipase A 2 Metabolites Mediate Endothelin Stimulation of the Human Brain Natriuretic Peptide Promoter

Hypertension ◽  
2000 ◽  
Vol 36 (suppl_1) ◽  
pp. 721-721
Author(s):  
Quan He
Keyword(s):  
Gene Expression ◽  
Brain Natriuretic Peptide ◽  
Natriuretic Peptide ◽  
Promoter Activity ◽  
Luciferase Activity ◽  
Phospholipase A ◽  
Luciferase Reporter ◽  
Luciferase Reporter Gene ◽  
P450 Monooxygenase ◽  
Stimulation Of

P155 Brain natriuretic peptide (BNP) gene expression accompanies cardiac hypertrophy and heart failure. The vasoconstrictor endothelin-1 (ET)may be involved in the development of these diseases. ET has also been shown to activate phospholipase A 2 (PLA 2 ). Thus we studied whether ET and PLA 2 metabolites regulate BNP gene expression. The hBNP promoter (-1818 to + 100) coupled to a luciferase reporter gene was transferred into neonatal ventricular myocytes (NVM),and luciferase activity was measured as an index of promoter activity. ET (10 -7 M)induced BNP mRNA in NVM as assessed by Northern blot. It also stimulated the hBNP promoter 4-fold vs control, an effect completely inhibited by actinomycin D. To test the involvement of different PLA 2 isoforms, transfected cells were treated with the Ca ++ -independent PLA 2 (iPLA 2 )inhibitor bromoenol lactone (BEL), the cytosolic PLA 2 inhibitor methyl arachidonyl fluorophosphonate, or the secretory PLA 2 inhibitor ONO-RS-082 prior to stimulation with ET. Only the iPLA 2 inhibitor BEL prevented ET-stimulated hBNP promoter activity. The PLA 2 metabolite lysophosphatidic acid (LPA) also activated the hBNP promoter (2.2-fold; n = 3), but lysophosphatidylcholine did not. To test whether arachidonic acid metabolites are involved in ET’s effect, cells were pretreated with either a lipoxygenase (LO), cyclooxygenase, or p450 monooxygenase inhibitor. Only the LO inhibitor baicalein prevented ET stimulation of the hBNP promoter. Finally, we studied the involvement of cis elements in ET-stimulated hBNP promoter activity. Deletion of BNP promoter sequences from -1818 to -408 and from -408 to -40 reduced ET’s effect by 54% and 78%, respectively. Moreover, ET-stimulated luciferase activity was reduced by 53% when the GATA element (at position -85 relative to the start site of transcription) was mutated. These data suggest that: 1) ET activates the hBNP promoter through a transcriptional mechanism; 2) LPA, perhaps generated by a BEL-sensitive iPLA 2 , is involved in ET’s effect; 3) a LO pathway may also mediate ET signaling; and 4) ET regulation of the hBNP promoter targets both distal and proximal cis elements, including GATA.

scholarly journals MKL-1 regulates the stem cell marker. CD44 in breast cancer cells

2019 ◽  
Vol 78 ◽  
pp. 01002
Author(s):  
Zhou-Tong Dai ◽  
Ao Yao ◽  
Yuan Xiang ◽  
Jia Peng Li ◽  
Wei Guo ◽  
...  
Keyword(s):  
Gene Expression ◽  
Malignant Tumors ◽  
Regulation Of Gene Expression ◽  
Gene Promoter ◽  
Expression Regulation ◽  
Stem Cell Marker ◽  
Luciferase Reporter ◽  
Regulation Mechanism ◽  
Luciferase Reporter Gene ◽  
Factors Affecting

CD44, cluster of differentiation 44 is a typical marker of stem cells. At present, it has been found that CD44 is prevalent in various human malignant tumors, but its expression regulation mechanism is still not clear. The initiation of gene expression, the modification of RNA levels, and the regulation of protein levels are the main factors affecting the expression level of genes, and the most critical one is the regulation of gene expression by signaling pathways. Up to now, there has been no report on the role of MKL-1 in the cloning of the cd44 promoter. Therefore, this study intends to clone the cd44 gene promoter, construct its luciferase reporter gene vector, transfect the MKL-1 overexpression vector, and analyze how it affects transcriptional activity, in order to further study the expression regulation of cd44. The mechanism provides a powerful tool in the future.

scholarly journals Human Prolactin Gene Promoter Regulation by Estrogen: Convergence with Tumor Necrosis Factor-α Signaling

Endocrinology ◽  
2007 ◽  
Vol 149 (2) ◽  
pp. 687-694 ◽  
Author(s):  
A. D. Adamson ◽  
S. Friedrichsen ◽  
S. Semprini ◽  
C. V. Harper ◽  
J. J. Mullins ◽  
...  
Keyword(s):  
Gene Promoter ◽  
Gh3 Cells ◽  
Luciferase Reporter ◽  
Luciferase Reporter Gene ◽  
Estrogen Response ◽  
Synergistic Activation ◽  
Prolactin Gene ◽  
Human Prolactin ◽  
Factor Α

Estrogens have been implicated in the regulation of prolactin gene expression in man, although previous studies have not defined the molecular mechanism whereby estradiol activates the human prolactin gene promoter (hPrl). We found that estradiol induced a reproducible 1.8-fold activation of the hPrl gene promoter, using pituitary GH3 cells stably transfected with a 5000-bp hPrl promoter fragment linked to luciferase reporter gene. This activation was blocked by treatment with estrogen receptor (ER) antagonists 4-hydroxytamoxifen and ICI-182,780. Promoter deletion and mutagenesis experiments identified a functional estrogen response element (ERE) sequence 1189 bp upstream of the transcription start site that was responsible for estrogen-mediated promoter activation. This site differed from the consensus ERE sequence by two base pairs, one in each half-site. This ERE was identified to be functional through binding ERα in EMSAs. Chromatin immunoprecipitation assays confirmed ERα binding to this sequence in vivo in the absence of ligand, with increased recruitment when cells were cultured in the presence of estradiol. When cells were treated with both estradiol and TNFα, we observed synergistic activation of the hPrl promoter, which was mediated by the −1189-bp ERE. Mutagenesis of this ERE abolished the promoter-activating effect not only of estradiol but also of TNFα. These data suggest a novel, promoter-specific signaling interaction between estrogen and TNFα signaling, which is likely to be important for prolactin regulation in vivo.

Inhibition of inducible TNF-α expression by oxaspirodion, a novel spiro-compound from the ascomycete Chaetomium subspirale

2004 ◽  
Vol 385 (9) ◽  
pp. 829-834 ◽  
Author(s):  
Jan Rether ◽  
Gerhard Erkel ◽  
Timm Anke ◽  
Olov Sterner
Keyword(s):  
Gene Expression ◽  
T Cells ◽  
Transcription Factor ◽  
Mode Of Action ◽  
Promoter Activity ◽  
Spiro Compound ◽  
Luciferase Reporter ◽  
Luciferase Reporter Gene ◽  
Jurkat T Cells ◽  
Tnf Α

Abstract In a search for compounds inhibiting the inducible TNF-αa promoter activity in T cells, a new spiro-compound, designated oxaspirodion, was isolated from fermentations of the ascomycete Chaetomium subspirale. Oxaspirodion inhibited TNF-α promoter-driven luciferase reporter gene expression with an IC50 value of 2.5 µg/ml (10 µM) in TPA/ionomycin-stimulated Jurkat T cells. Studies on the mode of action of the compound revealed that the inhibition of the TNF-α promoter activity is caused by an inhibition of the phosphorylation of the ERK1/2 kinases. In addition, oxaspirodion inhibited the activation of the transcription factor NF-κB, which is involved in the inducible expression of many proinflammatory genes.

scholarly journals Fibroblast Growth Factors Regulate Prolactin Transcription via an Atypical Rac-Dependent Signaling Pathway

2003 ◽  
Vol 17 (10) ◽  
pp. 1921-1930 ◽  
Author(s):  
Twila A. Jackson ◽  
David M. Koterwas ◽  
Melissa A. Morgan ◽  
Andrew P. Bradford
Keyword(s):  
Gene Expression ◽  
Growth Factors ◽  
Signaling Pathway ◽  
Promoter Activity ◽  
Fibroblast Growth Factors ◽  
Dominant Negative ◽  
Pituitary Cells ◽  
Dependent Manner ◽  
Fibroblast Growth ◽  
Prl Gene

Abstract Fibroblast growth factors (FGFs) play a critical role in pituitary development and in pituitary tumor formation and progression. We have previously characterized FGF signal transduction and regulation of the tissue-specific rat prolactin (rPRL) promoter in GH4 pituitary cells. FGF induction of rPRL transcription is independent of Ras, but mediated by a protein kinase C-δ (PKCδ)-dependent activation of MAPK (ERK). Here we demonstrate a functional role for the Rho family monomeric G protein, Rac1, in FGF regulation of PRL gene expression via an atypical signaling pathway. Expression of dominant negative Rac, but not RhoA or Cdc42, selectively inhibited FGF-induced rPRL promoter activity. Moreover, expression of dominant negative Rac also attenuated FGF-2 and FGF-4 stimulation of MAPK (ERK). However, in contrast to other Rac-dependent signaling pathways, FGF activation of rPRL promoter activity was independent of the c-Jun N-terminal kinase (JNK) and phosphoinositide 3-kinase/Akt cascades. FGFs failed to activate JNK1 or JNK2, and expression of dominant negative JNK or Akt constructs did not block FGF-induced PRL transcription. Consistent with the role of PKCδ in FGF regulation of PRL gene expression, activation of the rPRL promoter was blocked by an inhibitor of phospholipase Cγ (PLCγ) activity. FGF treatment also induced rapid tyrosine phosphorylation of PLCγ in a Rac-dependent manner. These results suggest that FGF-2 and FGF-4 activate PRL gene expression via a novel Rac1, PLCγ, PKCδ, and ERK cascade, independent of phosphoinositol-3-kinase and JNK.

scholarly journals Sequence of the 5′-flanking region and promoter activity of the human mucin gene MUC5B in different phenotypes of colon cancer cells

2000 ◽  
Vol 348 (3) ◽  
pp. 675-686 ◽  
Author(s):  
Isabelle VAN SEUNINGEN ◽  
Michaël PERRAIS ◽  
Pascal PIGNY ◽  
Nicole PORCHET ◽  
Jean-Pierre AUBERT
Keyword(s):  
Gene Expression ◽  
Transcription Start Site ◽  
Promoter Activity ◽  
Luciferase Reporter ◽  
Nuclear Factor ◽  
Start Site ◽  
Transcription Start ◽  
Mucin Gene ◽  
Intron 1 ◽  
Flanking Region

Control of gene expression in intestinal cells is poorly understood. Molecular mechanisms that regulate transcription of cellular genes are the foundation for understanding developmental and differentiation events. Mucin gene expression has been shown to be altered in many intestinal diseases and especially cancers of the gastrointestinal tract. Towards understanding the transcriptional regulation of a member of the 11p15.5 human mucin gene cluster, we have characterized 3.55 kb of the 5ʹ-flanking region of the human mucin gene MUC5B, including the promoter, the first two exons and the first intron. We report here the promoter activity of successively 5ʹ-truncated sections of 956 bases of this region by fusing it to the coding region of a luciferase reporter gene. The transcription start site was determined by primer-extension analysis. The region upstream of the transcription start site is characterized by the presence of a TATA box at bases -32/-26, DNA-binding elements for transcription factors c-Myc, N-Myc, Sp1 and nuclear factor ĸB as well as putative activator protein (AP)-1-, cAMP-response-element-binding protein (CREB)-, hepatocyte nuclear factor (HNF)-1-, HNF-3-, TGT3-, gut-enriched Krüppel factor (GKLF)-, thyroid transcription factor (TTF)-1- and glucocorticoid receptor element (GRE)-binding sites. Intron 1 of MUC5B was also characterized, it is 2511 nucleotides long and contains a DNA segment of 259 bp in which are clustered eight tandemly repeated GA boxes and a CACCC box that bind Sp1. AP-2α and GATA-1 nuclear factors were also shown to bind to their respective cognate elements in intron 1. In transfection studies the MUC5B promoter showed a cell-specific activity as it is very active in mucus-secreting LS174T cells, whereas it is inactive in Caco-2 enterocytes and HT-29 STD (standard) undifferentiated cells. Within the promoter, maximal transcription activity was found in a segment covering the first 223 bp upstream of the transcription start site. Finally, in co-transfection experiments a transactivating effect of Sp1 on to MUC5B promoter was seen in LS174T and Caco-2 cells.

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