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)

Resting human peripheral blood T cells synthesize proteins at very low rates and contain very low levels of eukaryotic initiation factor (eIF) 2 alpha mRNA. During mitogenic activation, the level of eIF-2 alpha mRNA increases at least 50-fold, an effect thought to be due primarily to intranuclear stabilization of the primary transcript (Cohen, R. B., Boal, T. R., and Safer, B. (1990) EMBO J. 9, 3831-3837). Analysis of sequences within the first intron revealed a region with homology to the "initiator" (Inr) sequence first described by Smale and Baltimore (Smale, S. T., and Baltimore, D. (1989) Cell 57, 103-113). This Inr element is positioned 450 bases downstream of the eIF-2 alpha promoter and is oriented to generate an overlapping antisense transcript. Deletion or mutation of the Inr element results in a reproducible 5-8-fold increase in the activity of an eIF-2 alpha promoter-driven CAT reporter gene and a corresponding 2.5-fold decrease in activity of an antisense driven luciferase reporter gene in vivo in 293 cells. In vitro transcription analysis also reveals antisense transcripts which depend on an intact Inr element and whose 5' ends map to sequences surrounding the Inr consensus sequence. A potential role for double-stranded RNA generated by these overlapping divergent transcription units in the regulation of eIF-2 alpha gene expression in T cells is suggested.
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PMID:Role of sequences within the first intron in the regulation of expression of eukaryotic initiation factor 2 alpha. 137 7

Transient transfection is a widely used tool for the identification of cis-acting regulatory elements. These elements are detected by their effect on the expression of a reporter gene, which is quantified by measuring the reporter gene product in the form of mRNA, protein (hGH), or enzymes (CAT, luciferase). Measurements of mRNA levels have several advantages over enzyme or protein assays. However, mRNA quantification by RNase protection or S1 mapping has considerably lower signal-to-background ratio than protein assays and is therefore less sensitive. In this paper we report the development of a system that takes advantage of the polymerase chain reaction (PCR) to quantify rabbit beta-globin reporter gene expression. Cells are co-transfected with constructs whose activity is to be tested and a reference plasmid with a small deletion in the second exon of the beta-globin gene. We show that the ratio of the two amplified cDNA signals is a highly reliable measure of test gene expression. The sensitivity of this assay is at least 1000-fold higher than RNase protection.
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PMID:A PCR-based assay for reporter gene expression. 147 39

Studies of gene regulation are greatly facilitated by the ability to transfect DNA into cultured cells. We examined a variety of transfection techniques to optimize transient expression of the human glycoprotein hormone alpha-gene in primary pituitary cells and subsequently investigated the regulation of alpha-promoter transcription. Expression vectors driven by either the rous sarcoma virus-chloramphenicol acetyl transferase (RSVCAT) or the human alpha-gene (alpha CAT) promoters were transfected into cultures of dispersed female rat pituitary cells using calcium phosphate (CaPO4), diethylaminoethyl-dextran, lipofection, and electroporation procedures. CAT activity was optimal using the CaPO4 technique, resulting in 511 +/- 49% and 57 +/- 5% conversion/100 micrograms protein/4 h for RSVCAT and alpha CAT, respectively. Immunohistochemical analyses of alpha CAT expression using anti-CAT monoclonal antibodies demonstrated that the alpha-gene promoter is expressed in pituitary cells, predominantly if not exclusively, in gonadotropes and thyrotropes. Hormonal regulation of alpha-promoter activity was assessed using both the CAT and the luciferase (LUC) reporter systems. alpha-Promoter activity was significantly (P less than 0.001) stimulated by 8-bromo-cAMP (217% increase), GnRH (75% increase), GnRH agonist analog (141% increase), and TRH (75% increase). The expression of control plasmids (RSVLUC, TKLUC, pOLUC) was not affected by treatment with these agents. We conclude that CaPO4-mediated transfection allows analyses of transient gene expression in primary pituitary cells. The alpha-promoter directs expression specifically in pituitary cells, predominantly gonadotropes and thyrotropes. alpha-Gene transcription is stimulated by GnRH, TRH, and 8-bromo-cAMP.
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PMID:Regulation of transfected glycoprotein hormone alpha-gene expression in primary pituitary cell cultures. 255 99

A picornavirus hybrid genome was constructed in which the internal ribosomal entry site (IRES) of encephalomyocarditis virus was inserted between the 5' non-translated region and the open reading frame of poliovirus (PV), type 1 (Mahoney). Upon transfection into HeLa cells, the hybrid RNA replicated and yielded a derivative of PV (W1-PNENPO). The PV IRES could be removed from pPNENPO, which resulted in a hybrid picornavirus (W1-P108ENPO) in which the translation of the PV open reading frame normally promoted by the type 1 IRES of PV was promoted by the type 2 IRES of encephalomyocarditis virus. This result indicates that these elements are not likely to contain cis-acting elements necessary for PV replication or encapsidation. A foreign gene (bacterial chloramphenicol acetyltransferase, CAT) was inserted into pPNENPO cDNA between the PV and encephalomyocarditis virus IRES elements. The dicistronic RNA replicated in HeLa cells and yielded a derivative of PV (W1-DICAT) with a genome 17% longer than that of wild-type PV. CAT assays and immunoblot analyses showed that the viral RNA efficiently expressed the foreign gene in cell culture. The CAT activity diminished somewhat with each passage of the dicistronic virus, an observation which suggested that the inserted gene had a deleterious effect on viral replication. However, even after five virus passages, a significant quantity of the foreign gene was still expressed. Insertion of the open reading frame of luciferase (67 kDa) resulted in an RNA species that replicated and expressed luciferase for up to 20 hr after transfection. However, this elongated RNA was not encapsidated.
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PMID:Polioviruses containing picornavirus type 1 and/or type 2 internal ribosomal entry site elements: genetic hybrids and the expression of a foreign gene. 750 72

One of the principal aims of our research is to determine the mechanisms which direct renin gene expression to different sites. We recently demonstrated that human renin (hRen) 5'-flanking DNA sequences -148 +/- 11 can drive the transient expression of a linked luciferase reporter gene transfected into pituitary GC cells. This activity was found to be dependent on the binding of Pit-1 to a site approximately 70 bp upstream from the transcription start site. Pit-1 is a pituitary-specific transcription factor which is involved in directing the cell-specific expression of growth hormone (GH) and prolactin (PRL) gene expression to somatotrope and lactotrope cells of the anterior pituitary. Thus, Pit-1 may be play a role in directing the expression of renin to primate lactotrope cells. Renin promoter-driven luciferase or CAT hybrid genes were found to be expressed following transfection into primary, or early passage cell cultures of placental chorionic membranes, and the renin-secreting renal tumor cell line As4.1. As with GC cells, deletion or mutagenesis of the Pit-1 site reduced activity several-fold in both placental and renal cells. These results suggest that members of the POU family of transcription factors, or some other closely related group such as the Hox proteins, participate in directing renin gene expression to placental and juxtaglomerular cells.
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PMID:A Pit-1 binding site in the human renin gene promoter stimulates activity in pituitary, placental and juxtaglomerular cells. 769 93

Replication-competent retroviral vectors (pFOV-1 to -3 and -7) were constructed on the basis of an infectious human foamy virus molecular clone which has deletions in the U3 region of the long terminal repeat and in the 3' region of the genome, previously identified to be nonessential for virus replication in vitro. The CAT and luciferase indicator genes were expressed as C-terminal fusion proteins to 215 amino acids of the viral Bet protein in the pFOV-1 vector. Introduction of the foot-and-mouth disease 2A protease sequence between the truncated bet coding sequence and the cloning site for the insertion of foreign genes in the pFOV-7 vector resulted in self-cleaving of the recombinant fusion protein. Alternatively, an internal ribosomal binding site was introduced, allowing expression of authentic foreign protein (pFOV-2 and -3 vectors). DNA fragments derived from the mouse hepatitis virus surface gene up to the length of 1.3 kb were inserted into pFOV-1. The vector constructs gave rise to viruses which were fully infectious in diploid human fibroblasts and recombinant viruses stably expressed high levels of foreign protein indicating that the pFOV vectors may be useful tools to study the effects of proteins of interest at least in tissue culture cells.
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PMID:Replicating foamy virus-based vectors directing high level expression of foreign genes. 779 69

A rare germ-line polymorphism in codon 47 of the p53 gene replaces the wild-type proline (CCG) with a serine (TCG). Restriction analysis of 101 human samples revealed the frequency of the rare allele to be 0% (n = 69) in Caucasians and 4.7% (3/64, n = 32) among African-Americans. To investigate the consequence of this amino acid substitution, a cDNA construct (p53 mut47ser) containing the mutation was introduced into a lung adenocarcinoma cell line (Calu-6) that does not express p53. A growth suppression similar to that obtained after introduction of a wild-type p53 cDNA construct was observed, in contrast to the result obtained by introduction of p53 mut143ala. Furthermore, expression of neither p53 mut47ser nor wild-type p53 was tolerated by growing cells. In transient expression assays, both mut47ser and wild-type p53 activated the expression of a reporter gene linked to a p53 binding sequence (PG13-CAT) and inhibited the expression of the luciferase gene under the control of the Rous sarcoma virus promoter (RSVluc). In the same assay, mut143ala did not activate the expression of PG13-CAT and produced only a slight inhibitory effect on RSVluc. These findings indicate that the p53 variant with a serine at codon 47 should be considered as a rare germ-line polymorphism that does not alter the growth-suppression activity of p53.
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PMID:Functional studies of a germ-line polymorphism at codon 47 within the p53 gene. 835 80

The discoidin proteins of Dictyostelium discoideum are highly expressed during development. The Disc I gamma promoter allows the regulation of heterologous protein expression by experimental conditions. We report conditions under which the promoter activity is efficiently repressed during growth in the wildtype strain AX2. In addition we show that a mutant which overexpresses the discoidins also overexpresses the reporter genes beta-galactosidase, luciferase and CAT 10- to 100-fold when these are placed under the control of a Disc I gamma promoter. This system may be generally useful for the overexpression of genes in Dictyostelium, both for functional studies in vivo and for the production of heterologous proteins for purification.
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PMID:Use of a transactive regulatory mutant of Dictyostelium discoideum in a eucaryotic expression system. 846 30

Signal-dependent activation of the transcription factor NF-kappaB is dominantly regulated by degradation of IkappaB-alpha protein. However, the signaling pathways that lead to the degradation are not clear. Here we report that mitogen-activated protein kinase/extracellular signal-regulated kinase kinase (MEK) kinase, an activator of stress-activated protein kinases/jun kinase-1 (SAPKs/JNK1), is involved in such signaling pathways. The transient overexpression of MEK kinase in NIH3T3 fibroblasts activates kappaB-CAT reporter expression in a synergistic manner with TNFalpha stimulation. In contrast, overexpression of kinase-negative MEK kinase suppresses TNFalpha-induced reporter expression. The overexpression of MEK kinase suppresses the inhibitory activity of co-transfected IkappaB-alpha on the kappaB-CAT or human immunodeficiency virus-long terminal repeat-luciferase reporter expression and causes the simultaneous disappearance of the overexpressed IkappaB-alpha. The disappearance of exogenous IkappaB-alpha by the overexpression of MEK kinase is prevented by calpain inhibitor-I, an inhibitor of IkappaB-alpha degradation. These results suggest that MEK kinase is a signal mediator involved in TNFalpha-induced NF-kappaB activation and that the activation of NF-kappaB by MEK kinase is regulated through the degradation of IkappaB-alpha.
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PMID:MEK kinase is involved in tumor necrosis factor alpha-induced NF-kappaB activation and degradation of IkappaB-alpha. 866 53

An androgen receptor (AR) gene mutation identified in the androgen-dependent human prostate cancer xenograft, CWR22, changed codon 874 in the ligand-binding domain (exon H) from CAT for histidine to TAT for tyrosine and abolished a restriction site for the endonuclease SfaNI. SfaNI digestion of AR exon H DNA from normal but not from prostate cancer tissue indicated H874Y is a somatic mutation that occurred before the initial tumor transplant. CWR22, an epithelial cell tumor, expresses a 9.6-kb AR mRNA similar in size to the AR mRNA in human benign prostatic hyperplasia. AR protein is present in cell nuclei by immunostaining as in other androgen-responsive tissues. Transcriptional activity of recombinant H874Y transiently expressed in CV1 cells in the presence of testosterone or dihydrotestosterone was similar to that of wild type AR. With dihydrotestosterone at a near physiological concentration (0.01 nM), H874Y and wild type AR induced 2-fold greater luciferase activity than did the LNCaP mutant AR T877A. The adrenal androgen, dehydroepiandrosterone (10 and 100 nM) with H874Y stimulated a 3- to 8-fold greater response than with wild type AR and at 100 nM the response was similar with the LNCaP mutant. H874Y, like the LNCaP cell mutant, was more responsive to estradiol and progesterone than was wild type AR. The antiandrogen hydroxyflutamide (10 nM) had greater agonist activity (4- to 7-fold) with both mutant ARs than with wild type AR. AR mutations that alter ligand specificity may influence tumor progression subsequent to androgen withdrawal by making the AR more responsive to adrenal androgens or antiandrogens.
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PMID:Dehydroepiandrosterone activates mutant androgen receptors expressed in the androgen-dependent human prostate cancer xenograft CWR22 and LNCaP cells. 909 97


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