Search results for "Luciferase"
showing 10 items of 67 documents
Metazoan Circadian Rhythm: Toward an Understanding of a Light-Based Zeitgeber in Sponges
2013
In all eukaryotes, the 24-h periodicity in the environment contributed to the evolution of the molecular circadian clock. We studied some elements of a postulated circadian clock circuit in the lowest metazoans, the siliceous sponges. First, we identified in the demosponge Suberites domuncula the enzyme luciferase that generates photons. Then (most likely), the photons generated by luciferase are transmitted via the biosilica glass skeleton of the sponges and are finally harvested by cryptochrome in the same individual; hence, cryptochrome is acting as a photosensor. This information-transduction system, generation of light (luciferase), photon transmission (through the siliceous spicules),…
Persistent episomal transgene expression in liver following delivery of a scaffold/matrix attachment region containing non-viral vector
2008
An ideal gene therapy vector should enable persistent transgene expression without limitations of safety and reproducibility. Here we report the development of a non-viral episomal plasmid DNA (pDNA) vector that appears to fulfil these criteria. This pDNA vector combines a scaffold/matrix attachment region (S/MAR) with a human liver-specific promoter (alpha1-antitrypsin (AAT)) in such a way that long-term expression is enabled in murine liver following hydrodynamic injection. Long-term expression is demonstrated by monitoring the longitudinal luciferase expression profile for up to 6 months by means of in situ bioluminescent imaging. All relevant control pDNA constructs expressing luciferas…
Elucidating the aryl hydrocarbon receptor antagonism from a chemical-structural perspective.
2020
The aryl hydrocarbon receptor (AhR) plays an important role in several biological processes such as reproduction, immunity and homoeostasis. However, little is known on the chemical-structural and physicochemical features that influence the activity of AhR antagonistic modulators. In the present report, in vitro AhR antagonistic activity evaluations, based on a chemical-activated luciferase gene expression (AhR-CALUX) bioassay, and an extensive literature review were performed with the aim of constructing a structurally diverse database of contaminants and potentially toxic chemicals. Subsequently, QSAR models based on Linear Discriminant Analysis and Logistic Regression, as well as two tox…
Transcription of human neuronal nitric oxide synthase mRNAs derived from different first exons is partly controlled by exon 1-specific promoter seque…
2006
AbstractThe human neuronal nitric oxide synthase (NOS1) gene is subject to extensive splicing. A total of 12 NOS1 mRNA species have been identified. They differ in their 5′ ends and are derived from 12 different first exons (termed exons 1a to 1l). Various cell lines whose NOS1 first exon expression patterns were representative of human brain, skin, and skeletal muscle were identified. These included A673 neuroepithelioma cells, SK-N-MC neuroblastoma cells, HaCaT keratinocyte-like cells, and C2C12 myocyte-like cells. In these cell lines, correlations were found between the exon 1 variants preferentially expressed and the promoter activities of their cognate 5′ flanking sequences. These data…
ADR1 and SNF1 Mediate Different Mechanisms in Transcriptional Regulation of Yeast POT1 Gene
1994
We studied the consequences of adr1 and snf1 mutations on POT1 gene expression in different growth conditions. The results obtained reveal that ADR1 and SNF1 genes affect POT1 transcription in different ways: ADR1 has a minor role in derepression in low concentration of glucose but is essential for activation in stationary phase whereas SNF1 is essential for derepression and activation, although it does not seem to be directly involved in the molecular mechanism of activation in stationary phase.
Analysis of expression of the gene encoding for the nuclear autoantigen La/SS-B using reporter gene constructs.
1998
In earlier studies mRNA isoforms encoding for the nuclear autoantigen La were identified. In an alternative La mRNA form the exon 1 was replaced with the exon 1'. Moreover, exon 1' La mRNAs were found to start at different 5'-regions. In dependence on the 5'-start the exon 1' La mRNAs encoded for up to three open reading frames upstream of the La frame, which starts in the exon 2. The exon 1' was located in the intron about 70 nts downstream of the exon 1. The exon 1' La mRNA was proposed to be the result of a promoter switch in combination with an alternative splicing mechanism. The commonly used technique to study the expression of a eucaryotic gene is to fuse a reportergene immediately d…
Dihydroquercetin (DHQ) induced HO-1 and NQO1 expression against oxidative stress through the Nrf2-dependent antioxidant pathway.
2013
Dihydroquercetin (DHQ) is a well-known antioxidant agent. In the present investigation, we reported for the first time that DHQ stimulates the expression of phase II detoxifying enzymes through the Nrf2-dependent signaling pathway. The IC50 values of DHQ for reduction of 2,2-diphenyl-1-picrylhydrazol (DPPH), reducing power assay, lipid peroxidation assay, and xanthine oxidase inhibition were 5.96, 4.31, 2.03, and 13.24 μM, respectively. DHQ possessed considerable protective activity from oxidative DNA damage. A luciferase reporter assay also demonstrated that DHQ-activated signaling resulted in the increased transcriptional activity of Nrf2 through binding to the ARE (antioxidant response e…
Role of hepatocyte nuclear factor 3γ in the expression of human CYP2C genes
2004
Hepatocyte nuclear factor 3 gamma (HNF-3 gamma) is an important transcription factor for the maintenance of specific liver functions. However, its relevance in the expression of human cytochrome P450 (CYP) genes has not yet been explored. Several HNF3 putative binding sites can be identified in human CYP2C 5'-flanking regions. Gene reporter experiments with proximal promoters revealed that HNF-3 gamma transactivated CYP2C8, CYP2C9, and CYP2C19 (25-, 4-, and 4-fold, respectively), but it did not transactivate CYP2C18. However, overexpression of HNF-3 gamma in hepatoma cells by means of a recombinant adenovirus induced CYP2C9, CYP2C18, and CYP2C19 mRNA (4.5-, 20-, and 50-fold, respectively) b…
Increased AICD generation does not result in increased nuclear translocation or activation of target gene transcription.
2008
A sequence of amyloid precursor protein (APP) cleavages culminates in the sequential release of the APP intracellular domain (AICD) and the amyloid beta peptide (Abeta) and/or p3 fragment. One of the environmental factors favouring the accumulation of AICD appears to be a rise in intracellular pH. Here we further identified the metabolism and subcellular localization of artificially expressed constructs under such conditions. We also co-examined the mechanistic lead up to the AICD accumulation and explored possible significances for its increased expression. We found that most of the AICD generated under pH neutralized conditions is likely cleaved from C83. While the AICD surplus was unable…
Human inducible nitric oxide synthase (iNOS) expression depends on chromosome region maintenance 1 (CRM1)- and eukaryotic translation initiation fact…
2012
Human inducible nitric oxide synthase (iNOS) is regulated on the expressional level mostly by post-transcriptional mechanisms modulating the mRNA stability. Another important step in the control of eukaryotic gene expression is the nucleocytoplasmic mRNA transport. Most cellular mRNAs are exported via the TAP/Nxt complex of proteins. However, some mRNAs are transported by a different mechanism involving the nuclear export receptor CRM1. Treatment of DLD-1 cells with the CRM1 inhibitor leptomycin B (LMB) or anti-CRM1 siRNAs reduced cytokine-induced iNOS expression. We could demonstrate that the iNOS mRNA is exported from the nucleus in a CRM1-dependent manner. Since CRM1 itself does not poss…