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PubMed1995

Inhibition of splicing of wild-type and mutated luciferase-adenovirus pre-mRNAs by antisense oligonucleotides.

We report the construction, characterization, and use of luciferase reporters to test the ability of antisense oligonucleotides to inhibit RNA splicing. beta-Globin and adenovirus introns were inserted into a luciferase cDNA, and luciferase expression was analyzed in transiently transfected cells. The adenovirus reporter expressed large amounts of luciferase, but two beta-globin constructs were inactive. RNA analyses determined that the beta-globin pre-mRNAs were not spliced. Mutagenesis of the beta-globin 5' splice site, branchpoint, and 3' splice site sequences to the adenovirus intron sequences promoted maximal splicing and luciferase activity; reciprocal changes in all three elements of the adenovirus intron eliminated luciferase activity. Wild-type and 3' splice site mutated adenovirus reporters were used to determine the ability of phosphorothioate deoxy and 2' methoxy oligonucleotides to inhibit splicing. RNase H activating oligodeoxynucleotides were better inhibitors of wild-type adenovirus expression than were 2' methoxy analogues. However, 2' methoxy oligonucleotides specific for the branchpoint were more effective inhibitors of splicing of adenovirus transcript containing the beta-globin branchpoint and 3' splice site. We suggest that pre-mRNAs with weak splice sites are potential targets for oligonucleotides that inhibit splicing by occupancy rather than cleavage of the transcripts.

Adenoviridae↗
PubMed1975

Bacterial luciferase. Binding of oxidized flavin mononucleotide.

Bacterial luciferase catalyzes a bioluminescent oxidation of reduced flavin mononucleotide; the products include a photon and oxidized FMN. The experiments reported here show that luciferase binds oxidized flavin mononucleotide in a 1:1 molar ratio with an apparent dissociation constant of 1.2 times 10-4 M at 3 degrees in 0.05 M 2,2-bis(hydroxymethyl)-2,2'2"-nitriloethanol (bis-tris), pH 7.0. Analysis of the binding at temperatures between 3 and 30 degrees indicates an enthalpy of binding (delta H a) of minus 10.0 kcal per mol. The absorption spectrum of luciferase-bound FMN shows considerable alteration relative to that of free flavin. There is one major peak at 366 nm, and the 445-nm band is resolved into two distinct peaks at 434 and 458 nm; this spectrum is indicative of binding in a nonpolar environment. The circular dichroism spectrum of FMN bound to luciferase has structure which correlates well with the optical absorption spectrum of the bound flavin. The detail in the spectra of the bound FMN probably reflects the resolution of vibrational structure which is blurred in polar environments. The optical activity shown by the CD spectrum presumably results from binding in an electronically asymmetric fashion. Although FMN free in solution is highly fluorescent, FMN bound to luciferase is nonfluorescent, thus indicating that the emitting species is not an excited state of product FMN located in the same site in which luciferase binds oxidized FMN.

Calorimetry↗
PubMed1994

An upstream region of the enoyl-coenzyme A hydratase/3-hydroxyacyl-coenzyme A dehydrogenase gene directs luciferase expression in liver in response to peroxisome proliferators in transgenic mice.

Peroxisome proliferators, which are structurally diverse nonmutagenic agents, induce hepatocarcinogenesis in rats and mice. Exposure to these xenobiotics leads to a rapid and coordinated transcriptional activation of the genes for the peroxisomal beta-oxidation enzyme system pathway in the liver. We have previously identified a peroxisome proliferator-responsive element in the 5'-flanking region of the rat peroxisomal hydratase/dehydrogenase (PBE) gene, the second enzyme in the beta-oxidation pathway. The peroxisome proliferator-responsive element in the PBE gene was shown to direct the induction of a luciferase reporter gene in vitro. We have now used this 3.2-kilobase 5'-flanking region of the PBE gene fused to the coding region of luciferase to generate transgenic mice. Three independent lines of transgenic mice expressed luciferase in response to ciprofibrate, a peroxisome proliferator. The induction of luciferase is specific to the liver; this agrees with the tissue-specific induction of PBE. Two other hypolipidemic drugs, nafenopin and Wy-14,643, were also capable of inducing luciferase activity in the liver. This study suggests that the PBE upstream element can be used to direct and modulate the expression of cloned genes by changing the levels of peroxisome proliferators. Also, the PBE-luciferase transgenic mouse should be an excellent model system for screening xenobiotics for potential peroxisome proliferator property.

3-Hydroxyacyl CoA Dehydrogenases↗
PubMed1977

Bacterial luciferase subunits are synthesized in equal quantities.

Synthesis of luciferase, an alpha beta dimer, occurs during a relatively short period of time near the end of exponential growth of Beneckea harveyi. The rates of synthesis of the individual alpha and beta chains of luciferase are compared by quantitating the molar ratio of total cellular alpha to that of beta at different growth stages. The addition of exogenous alpha or beta subunit to crude lysates of cells taken prior to and during the luciferase induction produces no increase in luciferase activity. This result, together with previous evidence that there are no antigenically cross-reacting precursors, allows us to conclude that luciferase alpha and beta chains are synthesized pari passu, i.e. in equal proportions, and exist primarily in the alpha beta dimeric form. It is also shown that insoluble sedimentable cellular materials contain no detectable luciferase subunits.

Gram-Negative Anaerobic Bacteria↗
PubMed1993

Folding of bacterial luciferase involves a non-native heterodimeric intermediate in equilibrium with the native enzyme and the unfolded subunits.

Bacterial luciferase is a heterodimeric enzyme that catalyzes the reaction of reduced FMN, O2 and an aliphatic aldehyde to yield the carboxylic acid and an excited flavin that emits blue-green light upon return to ground state. The two subunits of the luciferase from Vibrio harveyi, alpha and beta, have molecular weights of 40,108 and 36.349, respectively; the single active center resides primarily, if not exclusively, on the alpha subunit. We have found that bacterial luciferase can be unfolded in urea-containing 50 mM phosphate buffer, pH 7.0, and refolded by dilution of the urea with final luciferase concentrations of 5-25 micrograms/ml. We have analyzed the urea-induced equilibrium unfolding of bacterial luciferase by monitoring changes in both the far ultraviolet circular dichroism (predominantly secondary structure) and intrinsic fluorescence emission (predominantly tertiary structure) resulting from incubation in various concentrations of urea at 18 degrees C for 18-24 h. Both spectral methods indicated a biphasic unfolding transition; the first phase was protein concentration-independent, whereas the second phase was protein concentration-dependent. Equilibrium unfolding curves showed an increase in fluorescence up to 2 M urea followed by a decrease in intensity and red shift of the emission maximum. The ratio of the fluorescence emission in the presence of 2 M urea relative to that in the absence of urea was greater when fluorescence was excited at 295 nm than at 280 nm. The fluorescence increase in the 0-2 M urea range corresponded to the first phase of the biphasic unfolding process. The urea-induced loss of luciferase enzymatic activity appeared to correspond to the first transition observed with the spectroscopic methods, and likewise to be protein concentration-independent. These observations suggested a three-state unfolding mechanism in which the native heterodimeric enzyme rearranges to an inactive heterodimeric species that is well populated, followed by dissociation and unfolding of the alpha and beta subunits. The data were fit to a three-state mechanism using a nonlinear least squares method. At 18 degrees C in 50 mM phosphate, pH 7.0, the free energy change for the interconversion of the active heterodimer and the inactive heterodimeric species was estimated to be 4.52 +/- 0.30 kcal/mol; the free energy change for the interconversion of the inactive heterodimer and the individual subunits was 19.7 +/- 0.2 kcal/mol.(ABSTRACT TRUNCATED AT 400 WORDS)

Circular Dichroism↗
PubMed2025

Luciferase-Based Reporter Assay for the Assessment of Aurora A-Kinase Activity in Mitotic Cycle.

Luciferase-based reporter assay is an important tool that employs bioluminescence to quickly and precisely investigate the gene of interest's promoter activity by reporter gene expression at the transcriptional level. The promoter of the gene of interest is fused with the reporter gene (a gene that produces luciferase enzymes) and then transfected into the cells. Luciferase is an enzyme that catalyzes a chemical reaction to produce light. The bioluminescence activity of the luciferase gene in the transfected cells is directly proportional to the expression of the gene of interest, which is measured by using a luminometer. In this chapter, we outline the use of a dual-reporter luciferase assay to measure Aurora A kinase activity during the mitotic cycle.

Genes, Reporter↗
PubMedDate not supplied

The effect of detergents on firefly luciferase reactions.

The reaction rate of ATP-limited firefly luciferase-catalysed reactions, is affected by the presence of detergents. Anionic detergents inhibit luciferase activity without causing significant enzyme inactivation during the reaction. Cationic detergents increase reaction rate several-fold with a sharply defined optimum concentration of detergent for the effect. However, cationic detergents inactivate firefly luciferase during the reaction, resulting in a continuously decreasing reaction rate. Under such conditions, peak light intensity must be used as an indication of initial reaction rate. The inactivation rate increases with increasing detergent concentration. Non-ionic and zwitterionic detergents increase reaction rate over a broad range of detergent concentrations. Enzyme stability during the reaction is not affected by non-ionic detergents and only affected by zwitterionic detergents at high detergent concentration. Cyclodextrins, which can increase reaction rates of some chemiluminescent reactions, have little effect on firefly luciferase activity. Assays for ATP using firefly luciferase must be internally standardized by the constant addition technique in which a known amount of ATP is added to the test sample, since external calibration of such assays, by reference to a previously prepared standard curve, can lead to imprecision when detergents are present.

Adenosine Triphosphate↗
PubMedDate not supplied

Bovine serum albumin interacts with bacterial luciferase.

Bovine serum albumin (BSA) affects the amount of light obtained from bacterial luciferase by competing with luciferase for one of the luciferase substrates, the aldehyde. At low aldehyde concentrations BSA behaves as an inhibitor, but at high aldehyde concentrations BSA relieves substrate inhibition. BSA reversibly binds decanal with a Ksi = 3.36 mumol/l, approximately half the affinity of luciferase for decanal (KM = 1.5 mumol/l). BSA also increased the rate of intermediate II dark decay. The data suggest that this involves a direct protein-protein (BSA-luciferase) interaction.

Aldehydes↗
PubMedDate not supplied

Expression and quantification of firefly luciferase under control of Rhizobium meliloti symbiotic promoters.

We have tested the use of firefly luciferase for monitoring regulated symbiotic nitrogen fixation gene expression. Broad-host-range plasmids carrying translational fusions of Rhizobium meliloti nifH, fixA and nifA promoters were constructed. Despite low levels of promoter activity the absence of Escherichia coli endogenous luminescence and the high sensitivity of the bioluminescent assay for firefly luciferase allowed rapid screening for functional luciferase expression. Plasmids containing symbiotic promoter-luc fusions were established in R. meliloti. Luciferase activity was detected and measured in both vegetative and symbiotic cells giving comparable results with those obtained by beta-galactosidase assays. In addition, the luciferase assay was quicker, more sensitive and could be carried out with unrestricted cells. Furthermore, bioluminescence was high enough in alfalfa nodules containing nifH-luc fusion to be observed by a dark-adapted eye and photographed.

Animals↗
PubMedDate not supplied

Imaging of light emission from the expression of luciferases in living cells and organisms: a review.

Luciferases are enzymes that emit light in the presence of oxygen and a substrate (luciferin) and which have been used for real-time, low-light imaging of gene expression in cell cultures, individual cells, whole organisms, and transgenic organisms. Such luciferin-luciferase systems include, among others, the bacterial lux genes of terrestrial Photorhabdus luminescens and marine Vibrio harveyi bacteria, as well as eukaryotic luciferase luc and ruc genes from firefly species (Photinus) and the sea pansy (Renilla reniformis), respectively. In various vectors and in fusion constructs with other gene products such as green fluorescence protein (GFP; from the jellyfish Aequorea), luciferases have served as reporters in a number of promoter search and targeted gene expression experiments over the last two decades. Luciferase imaging has also been used to trace bacterial and viral infection in vivo and to visualize the proliferation of tumour cells in animal models.

Animals↗
PubMed2004

Elemental sulfur: toxicity in vivo and in vitro to bacterial luciferase, in vitro yeast alcohol dehydrogenase, and bovine liver catalase.

The aim of this research was to analyze the effects and the modes of action of elemental sulfur (S(0)) in bioluminescence and respiration of Vibrio fischeri cells and the enzymes crude luciferase, pure catalase, and alcohol dehydrogenase (ADH). Metallic copper removed sulfur and reduced the toxicity of acetone extracts of sediment samples analyzed in the bioluminescence test. The sulfur inhibition of cell bioluminescence was noncompetitive with decanal, the luciferase substrate; reversible, with maximum toxicity after 15 min (EC(50) = 11.8 microg/L); and almost totally recovered after 2 h. In vitro preincubation of crude luciferase extract with sulfur (0.28 ppm) weakly inhibited bioluminescence at 5 min, but at 30 min the inhibition reached 60%. Increasing the concentration of sulfur in the parts per million concentration range in vitro decreased bioluminescence, which was not constant, but depended on exposure time, and no dead-end/total inhibition was observed. The redox state of enzymes in the in vitro system significantly affected inhibition. Hydrogen peroxide restored fully and the reducing agent dithiothreitol, itself toxic, restored only partially luciferase activity in the presence of sulfur. Sulfur (5.5 ppm) slightly inhibited ADH and catalase, and dithiothreitol enhanced sulfur inhibition. High sulfur concentrations (2.2 ppm) inhibited the bioluminescence and enhanced the respiration rate of V. fischeri cells. Elemental sulfur data were interpreted to show that sulfur acted on at least a few V. fischeri cell sites: reversibly modifying luciferase at sites sensitive to/protected by oxidative and reducing agents and by affecting electron transport processes, resulting in enhanced oxygen consumption. Sulfur together with an enzyme reducing agent inhibited the oxidoreductive enzymes ADH and catalase, which have --SH groups, metal ion cofactors, or heme, respectively, in their active centers.

Alcohol Dehydrogenase↗
PubMed1997

Specific immobilization of firefly luciferase through a biotin carboxyl carrier protein domain.

Firefly luciferase (Photinus pyralis) was fused with a histidine tag and a biotin carboxyl carrier protein (BCCP) domain at its amino terminus. Highly purified recombinant luciferase was obtained by a one-step purification protocol, utilizing immobilized metal affinity chromatography. The novel BCCP-luciferase had properties, stability, and activity similar to those of native luciferase. The biotin molecule on the BCCP domain allowed specific immobilization of BCCP-luciferase on avidin-coated surfaces via the biotin-avidin interaction.

Acetyl-CoA Carboxylase↗
PubMed1997

Engineering of functional chimeric protein G-Vargula luciferase.

Luciferase of Vargula hilgendorfli is infinitely stable at room temperature in dried state, and its light-emitting reaction is very simple. These unique characteristics of Vargula luciferase have prompted us to engineer chimeric protein, the other moiety chosen for conjugation being streptococcal protein G. A single domain of protein G which binds to IgG of a wide range of species was fused at the N-terminal region of Vargula luciferase. Unexpectedly, we found that the chimeric protein expressed in mammalian COS-1 cells had no IgG-binding ability, probably due to some sort of interaction between the two moieties or some conformational preferences of the IgG-binding domain of protein G when fused to Vargula luciferase. Here we report how we regained the IgG binding of protein G, by the intervention of three alpha-helices of protein A between protein G and luciferase. To our knowledge, the new chimeric protein provides the first reported model of this kind.

Animals↗
PubMed1999

Specific immobilization of in vivo biotinylated bacterial luciferase and FMN:NAD(P)H oxidoreductase.

Bacterial bioluminescence, catalyzed by FMN:NAD(P)H oxidoreductase and luciferase, has been used as an analytical tool for quantitating the substrates of NAD(P)H-dependent enzymes. The development of inexpensive and sensitive biosensors based on bacterial bioluminescence would benefit from a method to immobilize the oxidoreductase and luciferase with high specific activity. Toward this end, oxidoreductase and luciferase were fused with a segment of biotin carboxy carrier protein and produced in Escherichia coli. The in vivo biotinylated luciferase and oxidoreductase were immobilized on avidin-conjugated agarose beads with little loss of activity. Coimmobilized enzymes had eight times higher bioluminescence activity than the free enzymes at low enzyme concentration and high NADH concentration. In addition, the immobilized enzymes were more stable than the free enzymes. This immobilization method is also useful to control enzyme orientation, which could increase the efficiency of sequentially operating enzymes like the oxidoreductase-luciferase system.

Acetyl-CoA Carboxylase↗
PubMed2000

Luminometric quantitation of photinus pyralis firefly luciferase and Escherichia coli beta-galactosidase in blood-contaminated organ lysates.

Firefly luciferase and Escherichia coli beta-galactosidase chemiluminescent reporter gene assays are rapid and sensitive means of detecting reporter enzyme activities in cell lysates of both eukaryotic and prokaryotic systems. In these assays, expression vectors containing the luciferase or beta-galactosidase genes are transferred to cells in culture or animal tissues in vivo. Crude cell or organ lysates are then prepared and submitted to enzyme assays. The level of enzyme activity is proportional to the efficiency of gene delivery and expression. When used with modified substrates that emit light when cleaved by the appropriate enzyme, luciferase and beta-galactosidase activity can be detected luminometrically. Attempts to apply these assays to cell lysates contaminated with blood, as from any whole organ lysate, have had questionable results thus far because of light absorption by hemoglobin in the ranges of light emission by both of these assays. We have made several adjustments to standard chemiluminescent reporter gene assay protocols to minimize errors in quantitation contributed by hemoglobin. To this end, we have developed a method for quantitating the protein due to blood and due to the organ itself in a blood-contaminated organ lysate. We have also found that the use of a colorimetric protein assay that is unaffected by hemoglobin absorbance is preferred for protein quantitation. In conclusion, luciferase and beta-galactosidase assays can be applied to blood-contaminated organ lysates; however, the luciferase assay proved to be superior due to minimal endogenous activity and lower absorption by hemoglobin of light emitted by the enzyme product.

Animals↗
PubMed2002

Sodium butyrate stimulates the synthesis of firefly luciferase in transfected CHO cells but levels of BiP chaperone are unaffected.

A stably transfected CHO cell line (LUCLEAD) was used where the coding region of native Firefly luciferase was linked to the 3'-UTR of the bovine growth hormone, and the 5'-nucleotides coding for the albumin signal peptide were linked to the N-terminal end of the luciferase coding region. Incubation of cells with 1 or 2 mM sodium butyrate (SB) for 72 h had no effect on cell growth since cultures reached confluency at the same time as control cells. Although cell cultures incubated with SB at a concentration of 4 mM were only about 60% confluent the luciferase content was about 5-fold higher than that in control cells. Cells incubated with either 1 or 2 mM SB showed intermediate levels of luciferase content. The amount of the chaperone BiP in the cells was not affected by incubation with SB. The results indicate that SB can be used to effectively promote synthesis of recombinant luciferase.

Animals↗
PubMed2000

CFTR intron 1 increases luciferase expression driven by CFTR 5'-flanking DNA in a yeast artificial chromosome.

The DNA elements that account for the highly regulated expression of the cystic fibrosis transmembrane conductance regulator gene (CFTR) are poorly understood. The goal of this study was to assess the feasibility of using a yeast artificial chromosome (YAC)-based reporter gene construct to define these elements further. An approximately 350-kb YAC (y5'luc) was constructed by replacing CFTR with a luciferase reporter gene (luc). A second YAC (y5'lucI) was similarly constructed but included a putative positive regulatory element from CFTR intron 1. Stable Chinese hamster ovary (CHO-K1) cell clones were derived using each YAC to assess the role that luc copy number and the presence of intron 1 played in luc expression. The CHO-K1 clonal cell lines demonstrated a wide range of luciferase activity. On average, this activity was significantly higher in clones derived from y5'lucI. After correcting for luc copy number, the presence of intron 1 was still associated with an increase in luciferase activity (P < 0.05), despite the fact that luciferase activity did not correlate with luc copy number in y5'luc-derived clones (r = -0.12). In contrast, the luciferase activity correlated well with luc copy number in the clones derived from y5'luc (r = 0. 75). These data are consistent with a positive role for intron 1 in regulating CFTR expression, but suggest that copy number is not the only factor that determines expression levels, particularly when this element is present. This YAC-based reporter system will provide a unique strategy for further assessment of the cis-acting elements that control CFTR expression.

Animals↗
PubMed1999

Firefly luciferase as a reporter to study gene expression in Streptococcus mutans.

The utility of firefly luciferase as a reporter was tested in Streptococcus mutans. Under control of an endogenous promoter, the luciferase coding sequence was strongly expressed, while a promoterless version was indistinguishable from the background. Luciferase activity was easily extracted and the assay rapid and reproducible. In addition, the half-life of luciferase activity was found to be comparable to those of other frequently used reporters. Thus, firefly luciferase can readily be used as a reporter in S. mutans, a useful alternative to methods requiring radioactive isotopes.

Animals↗