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)

Basic fibroblast growth factor (bFGF) has been implicated in the regulation of cell proliferation and cholesterol metabolism. In studies reported herein, we show bFGF increases low density lipoprotein (LDL) binding, uptake, and degradation in arterial smooth muscle cells in a dose-dependent manner. This increase was paralleled by an increase in LDL receptor mRNA steady state levels. To determine if bFGF activated transcription of the LDL receptor gene, we transiently transfected smooth muscle cells with a gene construct consisting of the 5'-upstream promoter region of the DNA from the human LDL receptor gene ligated to a plasmid containing the luciferase gene. We found that bFGF and a protein kinase C (PKC) activator, phorbol 12-myristate 13-acetate, significantly induced luciferase activity driven by the LDL receptor promoter, whereas 25-hydroxycholesterol reduced the luciferase activity in bFGF-stimulated cells. These findings show that bFGF and PKC are inducing LDL receptor gene transcription. We also evaluated potential signal transduction pathways induced by bFGF to establish the mechanism(s) leading to the activation of the LDL receptor gene. Activation of the activity of FGF receptor tyrosine kinase in smooth muscle cells by ligand binding resulted in tyrosine phosphorylation of one of the FGF receptors and a 90-kDa-protein as well as increased tyrosine phosphorylation of phospholipase C-gamma. Parallel observations were made in that increased PKC and protein kinase A activities occurred with bFGF as compared with control cells. Inhibitors of receptor tyrosine kinase and other protein kinases significantly reduced transcription and surface expression of LDL receptor. Finally, several key enzymes that are central to the regulation of LDL-cholesteryl ester metabolism were also studied in bFGF-stimulated cells. An increase in acyl-CoA:cholesterol acyltransferase activity and cholesterol esterification was observed with bFGF stimulation, but there was no effect on the lysosomal or cytoplasmic cholesteryl ester hydrolase activities. Our findings suggest potential signal transduction pathways activated by bFGF which play a role in regulating transcription and surface expression of the LDL receptor.
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PMID:Basic fibroblast growth factor-induced low density lipoprotein receptor transcription and surface expression. Signal transduction pathways mediated by the bFGF receptor tyrosine kinase. 751 Jul 5

Vesicular stomatitis virus (VSV) has a broad host range. It replicates in the cytoplasm and causes rapid cytopathic effects. We show that following VSV infection, a nuclear factor that binds to a select set of interferon-stimulated responsive elements (ISRE) is induced in many cell types. This factor, tentatively called VSV-induced binding protein (VIBP), was estimated to have an approximate molecular mass of 50 kDa and was distinct from known members of the interferon regulatory factor family, that are known to bind to the ISRE. Induction of VIBP required tyrosine kinase activity but did not require cellular transcription. Treatment of cells with cycloheximide, which inhibits translation, only partially inhibited induction of VIBP. However, type I interferons and staurosporine, both of which inhibit VSV transcription, inhibited VIBP induction. Moreover, a double-stranded RNA analog, poly(I)-poly(C) also induced a DNA-binding activity very similar to that of VIBP. These results indicate that a preexisting cellular protein is activated upon VSV infection and that this activation requires primary viral transcripts. The functional activity of VIBP was analyzed in cells stably transfected with a herpesvirus thymidine kinase-luciferase reporter gene that is under control of the ISRE. While activity of the control promoter without ISRE was strongly inhibited following VSV infection (as a result of virus-mediated transcriptional shutdown of the host cell), the inhibition was reversed by the ISRE-containing promoter, albeit partially, which suggests that VSV infection differentially affects transcription of host genes. Although VIBP was induced in all other cells tested, it was not induced in embryonal carcinoma cells after VSV infection, suggesting developmental regulation of VIBP inducibility.
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PMID:Vesicular stomatitis virus infection induces a nuclear DNA-binding factor specific for the interferon-stimulated response element. 753 6

Growth hormone (GH) treatment of cells promotes activation of JAK2, a GH receptor (GHR)-associated tyrosine kinase. We now explore JAK2 regions required for GHR-induced signaling. Wild-type (WT) JAK2 and JAK2 molecules with deletions of the amino terminus (JAK2ATD), carboxyl terminus (JAK2CTD), or kinase-like domain (JAK2PKD) were each transiently coexpressed in COS-7 cells with the rabbit GHR. The following responses were assayed: GH-induced transactivation of a luciferase reporter governed by a c-fos enhancer element; GH-induced shift in the molecular mass of a cotransfected epitope-tagged extracellular signal-regulated kinase molecule; and GH-induced antiphosphotyrosine immunoprecipitability of the transfected JAK2 form. In each assay, WTJAK2 and JAK2PKD allowed GH-induced signaling, whereas JAK2ATD and JAK2CTD did not. Anti-GHR serum coimmunoprecipitated WTJAK2, JAK2PKD, and JAK2CTD, but not JAK2ATD. Finally, a chimera in which the JAK2 kinase domain replaced the GHR cytoplasmic domain signaled GH-induced transactivation. We conclude: 1) kinase-like domain deletion eliminates neither physical nor functional interaction between JAK2 and the GHR; 2) kinase domain deletion eliminates functional but not physical coupling of JAK2 to the GHR; 3) interaction with the GHR appears dependent on the NH2-terminal one-fifth of JAK2; and 4) a GH-responsive signaling unit can include as little as the GHR external and transmembrane domains and the JAK2 kinase domain.
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PMID:Regions of the JAK2 tyrosine kinase required for coupling to the growth hormone receptor. 754 Jan 78

We examined the effect of insulin on nuclear factor kappa B (NF-kappa B) activity in Chinese ovary (CHO) cells overexpressing wild-type (CHO-R cells) or -defective insulin receptors mutated at Tyr1162 and Tyr1163 autophosphorylation sites (CHO-Y2 cells). In CHO-R cells, insulin caused a specific, time-, and concentration-dependent activation of NF-kappa B. The insulin-induced DNA-binding complex was identified as the p50/p65 heterodimer. Insulin activation of NF-kappa B: 1) was related to insulin receptor number and tyrosine kinase activity since it was markedly reduced in parental CHO cells which proved to respond to insulin growth factor-1 and phorbol 12-myristate 13-acetate (PMA) activation, and was dramatically decreased in CHO-Y2 cells; 2) persisted in the presence of cycloheximide and was blocked by pyrrolidine dithiocarbamate, aspirin and sodium salicylate, three compounds interfering with I kappa B degradation and/or NF-kappa B.I kappa B complex dissociation; 3) was independent of both PMA-sensitive and atypical (zeta) protein kinases C; and 4) was dependent on Raf-1 kinase activity since insulin-stimulated NF-kappa B DNA binding activity was inhibited by 8-bromo-cAMP, a Raf-1 kinase inhibitor. Moreover, insulin activation of NF-kappa B-driven luciferase reporter gene expression was blocked in CHO-R cells expressing a Raf-1 dominant negative mutant. This is the first evidence that insulin activates NF-kappa B in mammalian cells through a post-translational mechanism requiring both insulin receptor tyrosine kinase and Raf-1 kinase activities.
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PMID:Insulin activates nuclear factor kappa B in mammalian cells through a Raf-1-mediated pathway. 759 58

The c-fos protooncogene is induced by GH rapidly, but transiently. Induction requires C kinase activation and the serum response element, and recent binding studies have also implicated the sis-inducible element (SIE). However, no systematic study of the promoter elements responsible for transactivation by GH has been undertaken. Here we used Chinese hamster ovary K1 cells transiently cotransfected with rabbit GH receptor and c-fos promoter-luciferase constructs to demonstrate that the major region responsible for GH induction is located between 284-396 base pairs upstream of the transcription start site. Full induction by GH requires all of the known elements located in this region to be intact, including the SIE or signal transducer and activator of transcription binding element. We also report novel negative elements located around -216 upstream of the start site that reduce induction by GH and provide gel shift evidence for factors binding in this region. Cotransfection of Chinese hamster ovary K1 cells with c-fms and c-fos promoter constructs followed by the addition of CSF-1 revealed that these same c-fos elements contribute to transactivation by c-fms. Serum also uses the same elements to induce c-fos expression, except for the SIE. These results indicate that GH receptor and c-fms tyrosine kinase operate through multiple common response elements to regulate c-fos gene expression despite their structural differences.
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PMID:Growth hormone and colony-stimulating factor 1 share multiple response elements in the c-fos promoter. 766 71

Biologically active amidated gastrin is synthesized by carboxyl-terminal alpha-amidation of a glycine-extended progastrin post-translational processing intermediate (G-Gly). Although plasma levels of G-Gly are equivalent to those of gastrin, G-Gly has essentially no acute effect on gastric acid secretion. However, we have observed that inhibition of gastrin amidation leads to increased plasma concentrations of G-Gly and enhanced gastric acid secretion. We hypothesized, therefore, that G-Gly might have a chronic effect to increase H+,K(+)-ATPase expression in gastric parietal cells. In the present studies, we observed that a 2-day preincubation with G-Gly significantly enhanced histamine-stimulated [14C]aminopyrine uptake by isolated canine gastric parietal cells but acutely administered G-Gly had no effect. On Northern blot analysis, both G-Gly and gastrin dose-dependently increased H+,K(+)-ATPase alpha-subunit gene expression with maximal induction (225 +/- 35 and 170 +/- 29% of basal, mean +/- S.E.) achieved at concentrations of 10(-9) M G-Gly and 10(-8) M gastrin, respectively. Using an H+,K(+)-ATPase alpha-subunit gene-luciferase chimeric reporter construct transfected into primary cultured parietal cells, we observed that both G-Gly and gastrin increased luciferase activity in a manner similar to that obtained by Northern blot analysis. L365,260, a specific gastrin/CCKB receptor antagonist, completely reversed the stimulation of luciferase activity induced by gastrin but had no effect on G-Gly-stimulated activity. Gastrin increased [Ca2+]i, although G-Gly did not, however, genistein (a tyrosine kinase inhibitor) significantly reduced induction of luciferase activity by both G-Gly and gastrin. Specific binding of 125I-Leu15-G2-17-Gly to gastric parietal cells was dose-dependently displaced by G2-17-Gly but not by gastrin nor L365,260. Gastrin peptides truncated at the carboxyl- (G1-13) and amino terminus (G5-17-Gly) both induced H+,K(+)-ATPase alpha-subunit gene expression and inhibited 125I-Leu15-G2-17-Gly binding, but were less potent than G2-17-Gly. These data indicate that G-Gly may have a functional role in potentiating gastric acid secretagogue action via enhanced expression of the gene responsible for H+ generation through action at a novel receptor that can be distinguished from the gastrin/CCKB receptor. Thus, both the substrate and product of the terminal progastrin processing reaction appear to have complementary functions in regulation of gastric acid secretion.
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PMID:Glycine-extended progastrin processing intermediates induce H+,K(+)-ATPase alpha-subunit gene expression through a novel receptor. 774 46

PTC-1, the predominant form of PTC oncogene in human papillary thyroid carcinoma, encodes a fusion protein containing the N-terminus of H4 (D10S170) fused 5' to the ret tyrosine kinase domain. Accordingly, the PTC-1 expression is driven by the H4 gene promoter. Our study showed that H4 is expressed in various human tissues, including thyroid. Furthermore, we have localized the transcriptional start sites of H4 to a region 100 to 190 bp upstream of the translation initiation site (ATG) by primer extension assay, and the H4 promoter to a region within 259 bp upstream of the ATG site by luciferase assay. Interestingly, protein sequence analysis indicated a potential coiled-coil domain in the N-terminal region of H4. Indeed, oligomerization was demonstrated by an in vitro assay with recombinant proteins containing this region. As dimerization is considered to be a crucial step for receptor tyrosine kinase activation, we hypothesize that both unscheduled expression of ret tyrosine kinase and constitutive oligomerization of PTC-1 proteins are responsible for PTC-1 transforming activity in thyroid.
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PMID:Characterization of the promoter region and oligomerization domain of H4 (D10S170), a gene frequently rearranged with the ret proto-oncogene. 775 54

To investigate the role of protein phosphorylation in the early phase of EPO-mediated signal transduction, we EPO-stimulated a murine erythroid cell line ELM-I-1 transformed by plasmids comprised of the c-fos enhancer/promoter linked to the luciferase gene. Using this reporter gene system, we previously showed that EPO-induced activation of the c-fos promoter can be detected rapidly and sensitively as an elevation of cellular luciferase activity. In this study, we first examined the role of protein tyrosine phosphorylation. The tyrosine phosphatase inhibitor orthovanadate not only induced luciferase activity by itself but enhanced the action of EPO. On the other hand, the tyrosine kinase inhibitors erbstatin and herbimycin suppressed the effect of EPO. Next, the role of protein kinase C (PKC) in the EPO response was assessed. The PKC activator phorbol myristate acetate (PMA) not only induced luciferase activity by itself but enhanced the action of Epo. On the other hand, the PKC inhibitor 1-(5-isoquinolynyl-sulfonyl)-2-methylpiperazine (H7) suppressed the effect of Epo and PMA, whereas a nonspecific protein kinase inhibitor, N-(2-Guanidinoethyl)-5-Isoquinolinesulfornamine (HA1004) inhibited the action of neither Epo nor PMA. Another known PKC inhibitor staurosporine (STSP) did not inhibit but rather enhanced the effect of Epo. This action of STSP was blocked by H7 but not by HA1004. These results suggest that the EPO-mediated early signal transduction pathway leading to c-fos expression involves protein-tyrosine phosphorylation, is modulated by tyrosine phosphatase activity and is positively regulated by PKC.
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PMID:Role of protein phosphorylation in EPO-mediated early signal transduction: analysis in the EPO-reactive cell line ELM-I-1 transfected with a c-fos-enhancer/promoter-luciferase reporter gene. 800 30

Signal transduction pathways activated by injury play a central role in coordinating the cellular responses that determine whether a cell survives or dies. GADD153 expression increases markedly in response to some types of cellular injury and the product of this gene causes cell cycle arrest. Using induction of GADD153 as a model, we have investigated the activation of the cellular injury response after treatment with taxol and cisplatin (cDDP). Activation of the GADD153 promoter coupled to the luciferase gene and transfected into human ovarian carcinoma 2008 cells correlated well with the increase in endogenous GADD153 mRNA after treatment with taxol but not after treatment with cDDP. Following treatment with cDDP, the increase in endogenous GADD153 mRNA was 10-fold greater than the increase in GADD153 promoter activity. Likewise, at equitoxic levels of exposure (IC80), cDDP produced a 5-fold greater increase in endogenous GADD153 mRNA than taxol. The tyrosine kinase inhibitor tyrophostin B46 had no significant effect on the ability of taxol to activate the GADD153 promoter, but inhibited activation of the GADD153 promoter by cDDP in a concentration-dependent manner. Tyrphostin B46 synergistically enhanced the cytotoxicity of cisplatin; however, the same exposure had no significant effect on the cytotoxicity of taxol. We conclude that (1) taxol and cDDP activate GADD153 promoter activity through different mechanisms; (2) the signal transduction pathway mediating induction by cDDP involves a tyrosine kinase inhibitable by tyrphostin B46; and (3) that inhibition of this signal transduction pathway by tyrphostin synergistically enhances cDDP toxicity.
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PMID:Cisplatin and taxol activate different signal pathways regulating cellular injury-induced expression of GADD153. 855 77

Isolation and characterization of genomic clones encoding human alpha-platelet derived growth factor receptor (HGMW-approved symbol PDGFRA) revealed that the gene spans approximately 65 kb and contains 23 exons. The 5'-untranslated region of the mRNA is encoded by exon 1, and a large intron of 23 kb separates exon 2 encoding the translation initiator codon AUG and the signal sequence. The locations of exon/intron boundaries in the extracellular immunoglobulin-like domains, the transmembrane domain, the two cytoplasmic tyrosine kinase domains, and the kinase insertion domain are very similar to those in c-kit and macrophage colony stimulating factor-1 receptor genes. The transcription start site was mapped to a position 393 bp upstream of the AUG translocation initiator codon by S1 mapping and primer extension analysis. The 5'-flanking region of the gene lacks a typical TATA box but contains a typical CCAAT box and GATA motifs. This region also contains potential sites for AP-1, AP-2, Oct-1, Oct-2, and Sp1. The 5'-flanking region of the gene was fused to the luciferase reporter gene, and transcription units of the gene were determined.
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PMID:Structure, organization, and transcription units of the human alpha-platelet-derived growth factor receptor gene, PDGFRA. 858 21


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