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Luciferase Induction (luciferase + induction)

Distribution by Scientific Domains
Medical Sciences60%
Life Sciences40%

Selected Abstracts

The chemopreventive compound curcumin is an efficient inhibitor of Epstein-Barr virus BZLF1 transcription in Raji DR-LUC cells,

MOLECULAR CARCINOGENESIS, Issue 3 2002
Manfred Hergenhahn
Abstract To characterize the effects of inhibitors of Epstein-Barr virus (EBV) reactivation, we established Raji DR-LUC cells as a new test system. These cells contain the firefly luciferase (LUC) gene under the control of an immediate-early gene promoter (duplicated right region [DR]) of EBV on a self-replicating episome. Luciferase induction thus serves as an intrinsic marker indicative for EBV reactivation from latency. The tumor promoter 12- O -tetradecanoylphorbol-13-acetate (TPA) induced the viral key activator BamH fragment Z left frame 1 (BZLF1) protein ("ZEBRA") in this system, as demonstrated by induction of the BZLF1 protein-responsive DR promoter upstream of the luciferase gene. Conversely, both BZLF1 protein and luciferase induction were inhibited effectively by the chemopreventive agent curcumin. Semiquantitative reverse transcriptase (RT)-polymerase chain reaction (PCR) further demonstrated that the EBV inducers TPA, sodium butyrate, and transforming growth factor-, (TGF-,) increased levels of the mRNA of BZLF1 mRNA at 12, 24, and 48 h after treatment in these cells. TPA treatment also induced luciferase mRNA with similar kinetics. Curcumin was found to be highly effective in decreasing TPA-, butyrate-, and TGF-,-induced levels of BZLF1 mRNA, and of TPA-induced luciferase mRNA, indicating that three major pathways of EBV are inhibited by curcumin. Electrophoretic mobility shift assays (EMSA) showed that activator protein 1 (AP-1) binding to a cognate AP-1 sequence was detected at 6 h and could be blocked by curcumin. Protein binding to the complete BZLF1 promoter ZIII site (ZIIIA+ZIIIB) demonstrated several specific complexes that gave weak signals at 6 h and 12 h but strong signals at 24 h, all of which were reduced after application of curcumin. Autostimulation of BZLF1 mRNA induction through binding to the ZIII site at 24 h was confirmed by antibody-induced supershift analysis. The present results confirm our previous finding that curcumin is an effective agent for inhibition of EBV reactivation in Raji DR-CAT cells (carrying DR-dependent chloramphenicol acetyltransferase), and they show for the first time that curcumin inhibits EBV reactivation mainly through inhibition of BZLF1 gene transcription. © 2002 Wiley-Liss, Inc. [source]

Estrogenic endpoints in fish early life-stage tests: Luciferase and vitellogenin induction in estrogen-responsive transgenic zebrafish

ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 1 2006
Rinus Bogers
Abstract This study incorporated specific endpoints for estrogenic activity in the early life-stage (ELS) test, as described in Guideline 210 of the Organization for Economic Cooperation and Development and traditionally used for toxicity screening of chemicals. A transgenic zebrafish model expressing an estrogen receptor,mediated luciferase reporter gene was exposed to ethi-nylestradiol (EE2), and luciferase activity as well as vitellogenin (VTG) was measured. Concentrations of EE2 were tested at 1, 3, or 10 ng/L for 30 d from fertilization or during only the last 4 d with dimethylsulfoxide (DMSO) as presolvent (0.01%). Exposure to EE2 induced no toxic effects. Mean body weights were significantly higher in groups exposed for 30 d in the presence of DMSO, but condition factors were not affected. Significant luciferase and VTG induction occurred following 30-d exposure (3 and 10 ng EE2/L), while only VTG levels were affected in the 4-d exposure (10 ng EE2/L). This study demonstrated the usefulness of incorporating estrogenic endpoints in the OECD ELS test, fitting the requirements for screening estrogenic activity of chemicals. Quantitative measurement of both VTG and luciferase activity proved to be rapid and sensitive. Additional value of using transgenic zebrafish lies in combining VTG measurement with the more mechanistic approach of luciferase induction in one experiment. [source]

Prostaglandin E2 inhibits BMP signaling and delays chondrocyte maturation

JOURNAL OF ORTHOPAEDIC RESEARCH, Issue 6 2009
Christine A. Clark
Abstract While cyclooxygenases are important in endochondral bone formation during fracture healing, mechanisms involved in prostaglandin E2 (PGE2) regulation of chondrocyte maturation are incompletely understood. The present study was undertaken to determine if PGE2 effects on chondrocyte differentiation are related to modulation of the bone morphogenetic protein (BMP) signaling pathway. In primary murine sternal chondrocytes, PGE2 differentially regulated genes involved in differentiation. PGE2 induced type II collagen and MMP-13, had minimal effects on alkaline phosphatase, and inhibited the expression of the maturational marker, type X collagen. In BMP-2,treated cultures, PGE2 blocked the induction of type X collagen. All four EP receptors were expressed in chondrocytes and tended to be inhibited by BMP-2 treatment. RCJ3.1C5.18 chondrocytes transfected with the protein kinase A (PKA) responsive reporter, CRE-luciferase, showed luciferase induction following exposure to PGE2, consistent with activation of PKA signaling and the presence of the EP2 and EP4 receptors. Both PGE2 and the PKA agonist, dibutyryl cAMP, blocked the induction of the BMP-responsive reporter, 12XSBE, by BMP-2 in RCJ3.1C5.18 chondrocytes. In contrast, PGE2 increased the ability of TGF-, to activate the TGF-,-responsive reporter, 4XSBE. Finally, PGE2 down-regulated BMP-mediated phosphorylation of Smads 1, 5, and 8 in RCJ3.1C5.18 cells and in primary murine sternal chondrocytes. Altogether, the findings show that PGE2 regulates chondrocyte maturation in part by targeting BMP/Smad signaling and suggest an important role for PGE2 in endochondral bone formation. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 27: 785,792, 2009 [source]

The chemopreventive compound curcumin is an efficient inhibitor of Epstein-Barr virus BZLF1 transcription in Raji DR-LUC cells,

MOLECULAR CARCINOGENESIS, Issue 3 2002
Manfred Hergenhahn
Abstract To characterize the effects of inhibitors of Epstein-Barr virus (EBV) reactivation, we established Raji DR-LUC cells as a new test system. These cells contain the firefly luciferase (LUC) gene under the control of an immediate-early gene promoter (duplicated right region [DR]) of EBV on a self-replicating episome. Luciferase induction thus serves as an intrinsic marker indicative for EBV reactivation from latency. The tumor promoter 12- O -tetradecanoylphorbol-13-acetate (TPA) induced the viral key activator BamH fragment Z left frame 1 (BZLF1) protein ("ZEBRA") in this system, as demonstrated by induction of the BZLF1 protein-responsive DR promoter upstream of the luciferase gene. Conversely, both BZLF1 protein and luciferase induction were inhibited effectively by the chemopreventive agent curcumin. Semiquantitative reverse transcriptase (RT)-polymerase chain reaction (PCR) further demonstrated that the EBV inducers TPA, sodium butyrate, and transforming growth factor-, (TGF-,) increased levels of the mRNA of BZLF1 mRNA at 12, 24, and 48 h after treatment in these cells. TPA treatment also induced luciferase mRNA with similar kinetics. Curcumin was found to be highly effective in decreasing TPA-, butyrate-, and TGF-,-induced levels of BZLF1 mRNA, and of TPA-induced luciferase mRNA, indicating that three major pathways of EBV are inhibited by curcumin. Electrophoretic mobility shift assays (EMSA) showed that activator protein 1 (AP-1) binding to a cognate AP-1 sequence was detected at 6 h and could be blocked by curcumin. Protein binding to the complete BZLF1 promoter ZIII site (ZIIIA+ZIIIB) demonstrated several specific complexes that gave weak signals at 6 h and 12 h but strong signals at 24 h, all of which were reduced after application of curcumin. Autostimulation of BZLF1 mRNA induction through binding to the ZIII site at 24 h was confirmed by antibody-induced supershift analysis. The present results confirm our previous finding that curcumin is an effective agent for inhibition of EBV reactivation in Raji DR-CAT cells (carrying DR-dependent chloramphenicol acetyltransferase), and they show for the first time that curcumin inhibits EBV reactivation mainly through inhibition of BZLF1 gene transcription. © 2002 Wiley-Liss, Inc. [source]

,2 adrenergic receptor 5, haplotypes influence promoter activity

BRITISH JOURNAL OF PHARMACOLOGY, Issue 8 2002
Sharon E Johnatty
Transcriptional control of the human ,2 adrenergic receptor gene (ADRB2) predominantly resides within a 549 base pair region immediately 5, to the start of translation. Within this region, four naturally occurring polymorphisms, ,468 C,G, ,367 T,C, ,47 T,C, and ,20 T,C, have been identified. To determine the individual site and haplotype effects of these polymorphisms, we generated 16 luciferase-based mutant constructs which were transiently transfected into HEK293 cells, and measured ADRB2 promoter-driven luciferase activity. Two of the 16 mutant constructs, GCCT (,468G, ,367C, ,47C, ,20T) and CTCT, showed a highly significant 3 fold decrease in luciferase induction relative to the reference CTTT. These haplotype effects could not be accounted for by the separate and additive effects of each site. These findings indicate that promoter polymorphisms interact to significantly alter ,2 adrenergic receptor expression, and should be examined further for their association with disease-related phenotypes. British Journal of Pharmacology (2002) 137, 1213,1216. doi:10.1038/sj.bjp.0704935 [source]