Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:1.14.14.3 (luciferase)
 38,195 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Experimental investigation of glioma biology and therapy requires a representative model and a convenient technique for regulating gene expression. We have established an in vivo model in which genetically modified rat C6 glioma cells (C6TL cells) are transplanted into nude mice brain, followed by specific transcriptional control of a transgene. Histologically, the tumors exhibit an astrocytic phenotype and closely resemble human malignant gliomas including diffuse brain invasion. Due to a stably integrated lacZ gene, individual tumor cells can be unequivocally identified in tissue sections by histochemistry for beta-galactosidase. Since C6TL cells carry the tet transactivator (tTA) gene, any additional gene under control of a tetracycline/tTA-responsive promoter can be transcriptionally regulated by the concentration of tetracycline. C6TL cells stably transfected with a tetracycline/tTA-responsive luciferase reporter gene showed 23-fold regulation of luciferase activity in vitro. After intracerebral transplantation a regulation of 4.5- to 8.3-fold was obtained, dependent on the concentration and the type of tetracycline in the drinking water. This model should be useful for studying the functional role of candidate genes in tumor biology as well as for experimental gene therapy studies.
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PMID:In vivo glioma model enabling regulated gene expression. 1086 92

Although the mechanism of action has not yet been defined, epidemiological studies have demonstrated an association between elevated arsenic levels in drinking water and the incidence of urinary bladder transitional cell carcinomas. In the current studies, we demonstrate that mice exposed to 0.01% sodium arsenite in drinking water develop hyperplasia of the bladder urothelium within 4 weeks of exposure. This was accompanied by the accumulation of inorganic trivalent arsenic, and to a lesser extent dimethylarsinic acid, in bladder tissue, as well as a persistent increase in DNA binding of the activating protein (AP)-1 transcription factor. AP-1 transactivation by arsenic also occurred in bladders of transgenic mice containing an AP-1 luciferase reporter. Consistent with these in vivo observations, arsenite increased cell proliferation and AP-1 DNA binding in a human bladder epithelial cell line. Gene expression studies using RNase protection assays, reverse transcription-PCR, and cDNA microarrays indicated that arsenite alters the expression of a number of genes associated with cell growth, such as c-fos, c-jun, and EGR-1, as well as cell arrest, such as GADD153 and GADD45. The proliferation-enhancing effect of arsenic on uroepithelial cells likely contributes to its ability to cause cancer.
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PMID:Arsenic mediates cell proliferation and gene expression in the bladder epithelium: association with activating protein-1 transactivation. 1091 55

Enhancement of transgene expression is an important issue in human gene therapy. Here we describe a novel system for enhancing transgene expression by cointroduction of plasmid DNA with FR901228, a water-soluble histone deacetylase inhibitor. When a luciferase expression vector was cointroduced into cells with FR901228, luciferase gene expression was enhanced 50-fold in the mouse melanoma cell line B16-F1 and 5200-fold in NIH3T3 cells in comparison to cells without the drug. Luciferase gene expression enhancement was dependent on both drug dose and treatment time. Acetylated histones increased in accordance with drug dose, and the activation of gene expression occurred at the transcriptional level. The stimulation of luciferase gene expression by FR901228 was also observed in a B16-F1 clone stably expressing luciferase. Cointroduction of the luciferase plasmid with FR901228 into a B16-F1 tumor mass activated luciferase gene expression 3- to 4-fold. Thus, activation of transgene expression by FR901228 may serve as a new tool for gene therapy.
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PMID:Amplification of transgene expression in vitro and in vivo using a novel inhibitor of histone deacetylase. 1093 82

The plant hormone abscisic acid (ABA) mediates many vital processes in plant growth and development, including seed dormancy, cell division, water use efficiency, and adaptation to drought, salinity, chilling, pathogen attack, and UV light. Our understanding of ABA signal transduction is fragmentary and would benefit from specific and facile probes of the process. Protoplasts from rice (Oryza sativa L. cv IR54) embryonic suspension cultures cotransformed with effector plasmids encoding the maize (Zea mays) VIVIPAROUS1 cDNA and/or the Arabidopsis dominant negative mutant (abi1-1) ABA-insensitive cDNA demonstrated genetic interactions of VIVIPAROUS1 and abi1-1 in transactivation of the ABA-inducible HVA1 promoter from barley (Hordeum vulgare), suggesting the mechanisms of these effectors are conserved among monocots and dicots. Trivalent ions have been shown to act as an effector of gene expression in plants and animals, although the mechanism of action is unknown. We show in two complementary transient ABA-inducible gene expression assays (beta-glucuronidase and luciferase enzymatic activities and quantitative flow cytometry of green fluorescent protein) that trivalent ions specifically interact with an ABI1-dependent ABA-signaling pathway leading to gene expression. Trivalent ions mimic ABA effects on gene expression and may be a useful tool to study ABA signaling.
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PMID:Trivalent ions activate abscisic acid-inducible promoters through an ABI1-dependent pathway in rice protoplasts. 1093 71

The effects of a number of quinones on the bioluminescence characteristics of a three-component enzymatic system containing alcohol dehydrogenase, bacterial luciferase, and NADH-FMN oxidoreductase were studied to find the most sensitive kinetic parameters of the system intended to be used in biological testing. Both direct and back reactions catalyzed by alcohol dehydrogenase were studied in the presence and in the absence of quinones. The kinetic parameters of the bioluminescent system were found to depend on the redox potentials and concentrations of quinones. The quinone-induced effects were shown to be associated with changes in the NAD+/NADH ratio in the chain of NADH-dependent enzymes. The three-enzyme system based on alcohol dehydrogenase is suggested as a bioluminescence test for ecological monitoring of waste water.
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PMID:[Effect of quinones on enzymatic bioluminescence of NADH-dependent systems]. 1099 99

In the kidney, water reabsorption is mainly regulated by the binding of arginine vasopressin to vasopressin type 2 (V2) receptors. These receptors are expressed selectively in principal cells of the collecting ducts. To identify molecular mechanisms responsible for the cell-specific expression of the V2 receptor, we have analyzed the proximal promoter of the corresponding gene. We report the identification of a 33-bp enhancer [collecting duct tissue-specific element 1 (CSE1)] that induced high levels of expression of the luciferase reporter gene in three collecting duct cell lines, but not in other renal cell lines. In gel shift assays, CSE1 bound a DNA-binding protein expressed selectively in collecting duct cell lines, and a 7-bp mutation, which abolished the activity of CSE1 in transient transfection experiments, also abolished the binding of this protein. Furthermore, decoy experiments performed using CSE1 showed that this sequence was involved not only in the expression of a construct containing 4.2 kb of the V2 receptor proximal promoter, but also in the expression of the endogenous V2 receptor gene. CSE1 appears to act mostly by counteracting the inhibitory effects of a strong ubiquitous repressor element that we called CIE1. Collectively, these results identify the first functional collecting duct-specific cis-acting element.
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PMID:Identification of a short cis-acting element in the human vasopressin type 2 receptor gene which confers high-level expression of a reporter gene specifically in collecting duct cells. 1104 82

Using the golden mutant zebrafish having a decrease in interfering pigmentation, we are developing transgenic lines in which DNA motifs that respond to selected environmental pollutants are capable of activating a reporter gene that can be easily assayed. We have begun with three response elements that recognize three important classes of foreign chemicals. Aromatic hydrocarbon response elements (AHREs) respond to numerous polycyclic hydrocarbons and halogenated coplanar molecules such as 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD; dioxin) and polychlorinated biphenyls. Electrophile response elements (EPREs) respond to quinones and numerous other potent electrophilic oxidants. Metal response elements (MREs) respond to heavy metal cations such as mercury, copper, nickel, cadmium, and zinc. Soon, we will include estrogen response elements (EREs) to detect the effects of environmental endocrine disruptors, and retinoic acid response elements (RARE, RXRE) to detect the effects of retinoids in the environment. Each of these substances is known to be bioconcentrated in fish to varying degrees; for example, 10(-17) M TCDD in a body of water becomes concentrated to approximately 10(-12) M TCDD in a fish, where it would act upon the AHRE motif and turn on the luciferase (LUC) reporter gene. The living fish as a sentinel will not only be assayed intact in the luminometer, but--upon several days or weeks of depuration--would be usable again. To date, we have established that zebrafish transcription factors are able to recognize both mammalian and trout AHRE, EPRE, and MRE sequences in a dose-dependent and chemical-class-specific manner, and that expression of both the LUC and jellyfish green fluorescent protein (GFP) reporter genes is easily detected in zebrafish cell cultures and in the intact live zebrafish. Variations in sensitivity of this model system can be achieved by increasing the copy number of response elements and perhaps by altering the sequence of each core consensus response element and flanking regions. This transgenic technology should allow for a simple, exquisitely sensitive, and inexpensive assay for monitoring aquatic pollution. We have already initiated studies using sentinel zebrafish to monitor a public drinking water source.
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PMID:Transgenic zebrafish as sentinels for aquatic pollution. 1108 5

We cloned the Slc14a2 gene and determined the genomic organization of the rat urea transporter UT-A. Slc14a2, the gene encoding the rat UT-A transporter, extends for more that 300 kb. The four known rat mRNA isoforms: UT-A1, UT-A2, UT-A3, and UT-A4 are transcribed from 24 exons. The Slc14a2 genomic map also accounts for 3'-untranslated sequences expressed alternatively in UT-A1, UT-A2, and UT-A3. We previously identified a TATA-less, tonicity-responsive promoter controlling the transcription of UT-A1, UT-A3, and UT-A4 from a single initiation site in the 5'-flanking region of the gene. Here, we describe a second, internal promoter in intron 12, which controls the transcription of UT-A2 starting from exon 13. This region contains a TATA motif upstream from the UT-A2 transcription start site, and shows consensus sequences for the cAMP response element (CRE) and for the tonicity enhancer (TonE) motif. Stimulation by cAMP induces UT-A2 mRNA expression in mIMCD3 cells, and luciferase activity in mIMCD3 cells transfected with those pGL3 constructs including the CRE sequences. Although long-term exposure to hypertonicity induces UT-A2 expression in mIMCD3 cells, hypertonicity does not induce significantly the activity of the promoter in intron 12. In summary, we describe the genomic structure of the rat UT-A urea transporter, encoded by the Slc14a2 gene. Our findings suggest that two promoters regulate transcription of the four UT-A isoforms, and that stimulation of transcription by vasopressin, mediated by cAMP and CRE sequences, and controlled by an intronic promoter, may contribute to the increase in UT-A2 expression during water deprivation.
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PMID:Cloning of the rat Slc14a2 gene and genomic organization of the UT-A urea transporter. 1126 55

A set of bioluminescent tests was developed to monitor water quality in natural and laboratory ecosystems. It consisted of four bioluminescent systems: luminous bacteria, coupled enzyme system NADH:FMN-oxidoreductase-luciferase and triplet enzyme systems with alcohol dehydrogenase and trypsin. The set of biotests was applied for a small forest pond (Siberia, Russia), laboratory microecosystems polluted with benzoquinone and a batch culture of blue-green algae. Thereby effects of natural water compared to those of models of heavy pollution and "bloom" of blue-greens on the bioluminescent tests were revealed. The set of biotests was not affected by a natural seasonal variability of water quality in the unpolluted pond, but responded to the heavy pollution and the "bloom" of blue-greens. The set of biotests could be recommended as the alarm test to control the acute toxicity of natural water bodies.
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PMID:The use of bioluminescent biotests for study of natural and laboratory aquatic ecosystems. 1127 13

12-O-Tetradecanoylphorbol-13-acetate (TPA) is widely used as a tumor promoter with organotropy in skin and esophagus. TPA-induced, organ-specific tumor promotion is not correlated with the distribution of its receptor, protein kinase C (PKC). Using five administration methods (painting, drinking, gavage feeding, i.p. injection, and i.v. injection), we analyzed TPA-stimulated activator protein-1 (AP-1) activity in various organs (liver, kidney, brain, lung, spleen, heart, stomach, colon, esophagus, and skin) from transgenic mice expressing the AP-1 luciferase reporter gene. Topical application of TPA by painting the skin on the back of mice raised AP-1 activity 122.6-fold, and the highest peak of AP-1 activity was at 12 h after administration of TPA. Drinking water containing TPA caused a 25.8-fold induction of AP-1 activity in the skin, whereas gavage feeding with TPA caused a 34.2-fold induction of AP-1 in the skin. Intraperitoneal or i.v. injection of TPA induced a 49.56-fold or 20.4-fold increase in AP-1 activity in the skin, respectively. The highest peaks of AP-1 activity in the skin were at 12 h after drinking, feeding, or injection of TPA. More interesting, in the esophagus, i.p. injection of TPA raised AP-1 activity 13.9-fold, drinking TPA raised AP-1 activity 8.4-fold, and painting with TPA caused a 2.4-fold induction of AP-1 activity. In the colon, i.p. injection of TPA raised AP-1 activity 3.9-fold, drinking TPA induced a 1.2-fold increase in AP-1 activity, but painting with TPA had no effect. AP-1 activity in other organs was not detectable after administration of TPA by painting, drinking, or injection. Phosphorylation of extracellular signal-regulated kinases in the skin increased at 12 h after painting, drinking, or i.p. injection of TPA. In addition, phosphorylation of p38 kinase was raised slightly after TPA administration, but phosphorylation of c-Jun NH(2)-terminal kinases was not detected at any time point after TPA administration. Similar changes in MAP kinases were also seen in the esophagus after TPA administration. These results indicate that the skin is the most sensitive organ to TPA induction of AP-1 activity. The data suggest that the organ-specific, tumor-promoting effect of TPA may be through AP-1 activation and phosphorylation of ERKs and p38 kinase.
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PMID:Organ-specific activation of activator protein-1 in transgenic mice by 12-o-tetradecanoylphorbol-13-acetate with different administration methods. 1135 30


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