Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.3.1.28 (chloramphenicol acetyltransferase)
 5,100 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

RON (recepteur d'origine nantais) is a receptor tyrosine kinase expressed in murine peritoneal resident macrophages and activated by macrophage-stimulating protein (MSP). The objectives of this investigation were to study the RON expression in exudate macrophages and the mechanisms by which RON inhibits inducible nitric oxide synthase (iNOS) expression induced by LPS and IFN-gamma. We found that mouse peritoneal resident and Con A-elicited macrophages collected on day 3 or day 5 express RON. Acute exudate macrophages collected on day 1 did not express RON. Activation of RON inhibited LPS- and IFN-gamma-induced macrophage nitric oxide production and iNOS mRNA accumulation. Similar inhibition was observed also in Raw264.7 macrophage cell lines transfected with human RON cDNA. In these cells, MSP induced RON phosphorylation concomitant with reduced iNOS mRNA expression and protein synthesis. Further, we show that activated RON inhibited the iNOS gene transcription activity as assessed by chloramphenicol acetyltransferase activity in Raw264.7 cells expressing RON. Wortmannin, a specific inhibitor of phosphatidylinositol-3 (PI-3) kinase, prevented the inhibitory effect of RON on the iNOS gene promoter activity and on the nitric oxide production induced by LPS and IFN-gamma. These effects were confirmed further by introducing a dominant-inhibitory PI-3 kinase p85 subunit in RON-expressing Raw264.7 cells. Taken together, our results suggest that RON is expressed in peritoneal macrophages at later stages of inflammation. Activation of RON by MSP in mature exudate macrophages inhibits LPS- and IFN-gamma-induced iNOS synthesis. PI-3 kinase is an important effector molecule required for RON-mediated inhibition of iNOS expression in macrophages.
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PMID:Activation of the RON receptor tyrosine kinase inhibits inducible nitric oxide synthase (iNOS) expression by murine peritoneal exudate macrophages: phosphatidylinositol-3 kinase is required for RON-mediated inhibition of iNOS expression. 979 31

The nuclear body is a cellular structure that appears to be involved in the pathogenesis of acute promyelocytic leukemia and viral infection. In addition, the nuclear body is a target of autoantibodies in patients with the autoimmune disease primary biliary cirrhosis. Although the precise function of the nuclear body in normal cellular biology is unknown, this structure may have a role in the regulation of gene transcription. In a previous investigation, we identified a leukocyte-specific, gamma interferon (IFN-gamma)-inducible autoantigen designated Sp140. The objectives of the present study were to investigate the cellular location of Sp140 with respect to the nuclear-body components PML and Sp100 and to examine the potential role of Sp140 in the regulation of gene transcription. We used adenovirus-mediated gene transfer to express Sp140 in human cells and observed that the protein colocalized with PML and Sp100 in resting cells and associated with structures containing PML during mitosis. In cells infected with the adenovirus expressing Sp140 and incubated with IFN-gamma, the number of PML-Sp100 nuclear bodies per cell increased but immunoreactive Sp140 was not evenly distributed among the nuclear bodies. Sp140 associated with a subset of IFN-gamma-induced PML-Sp100 nuclear bodies. To examine the potential effect of Sp140 on gene transcription, a plasmid encoding Sp140 fused to the DNA-binding domain of GAL4 was cotransfected into COS cells with a chloramphenicol acetyltransferase (CAT) reporter gene containing five GAL4-binding sites and a simian virus 40 enhancer region. The GAL4-Sp140 fusion protein increased the expression of the reporter gene. In contrast, Sp100 fused to the GAL4 DNA-binding domain inhibited CAT activity in transfected mammalian cells. The results of this study demonstrate that Sp140 associates with a subset of PML-Sp100 nuclear bodies in IFN-gamma-treated cells and that Sp140 may activate gene transcription. Taken together, these observations suggest that the nuclear bodies within a cell may be heterogeneous with respect to both composition and function.
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PMID:Structural and functional heterogeneity of nuclear bodies. 1033 Jan 82

In the present report, the effects of IFN-gamma and transforming growth factor beta1 (TGF-beta1) on major histocompatibility complex class II (MHC-II) gene expression in isolated mouse brain microglial cells, in the MH-S macrophage cell line and in the primary mouse macrophage cultures were examined. IFN-gamma is a potent inducer of MHC-II gene and this induction was further elevated in microglia by TGF-beta1, while TGF-beta1 inhibited IFN-gamma, induction in macrophages. The enhancing effect of TGF-beta1 was also detected in microglia at the protein level. Transient transfection of microglia with 5' deletional mutants of the MHC-II IAalpha promoter linked to the chloramphenicol acetyltransferase reporter gene demonstrated that TGF-beta1 acts at the transcriptional level to enhance the MHC-II expression induced by IFN-gamma.
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PMID:Effect of transforming growth factor-beta1 on microglial MHC-class II expression. 1069 7

In previous studies we demonstrated that the E1A DNA and proteins of group C adenovirus are present in excess in the lungs of patients with chronic obstructive pulmonary disease (COPD). Because adenovirus EIA gene products are known to regulate the expression of many genes by interacting with cellular transcription factors, we postulated that E1A enhances the production of inflammatory mediators and exacerbates the inflammatory process in smokers' lungs. We reported that LPS-induced ICAM-1 expression in A549 cells is upregulated by E1A. In the current study we investigated whether this regulation is mediated through the ICAM-1 promoter. A549 cells and primary human bronchial epithelial (HBE) cells were transiently cotransfected with a plasmid containing the ICAM-1 enhancer-promoter linked to the chloramphenicol acetyltransferase (CAT) reporter gene (pBS-CAT-P) and either a plasmid carrying the adenovirus 5 E1A gene (pE1Aneo) or a control plasmid (pneo). To compare the effect of transient versus stable E1A expression on the activity of this promoter, we also transiently transfected stable E1A-expressing A549 cells with pBS-CAT-P. Transient cotransfection of pE1Aneo and pBS-CAT-P had no effect on basal ICAM-1 promoter activity in A549 or HBE cells. After stimulation of A549 cells with TNF-alpha, IFN-gamma, or LPS, promoter activity was increased by two- to threefold in the presence of adenovirus EIA. In HBE cells, on the other hand, E1A repressed the ICAM-1 promoter after stimulation with IFN-gamma and LPS with little change after TNF-alpha stimulation. In stable E1A transfectants, ICAM-1 promoter activity was 2 to 2.5 times higher than in control transfectants with or without stimulation with TNF-alpha or LPS. These findings suggest that EIA can modulate the activity of the ICAM-1 promoter in lung epithelial cells and this modulation is different in cells of alveolar origin compared to bronchial epithelial cells.
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PMID:Effect of adenovirus E1A on ICAM-1 promoter activity in human alveolar and bronchial epithelial cells. 1094 78

Nitric oxide (NO) has diverse effects on immune responses and hepatic functions. In BNL CL.2 cells, the murine embryonic liver cells, inducible nitric oxide synthase (iNOS) mRNA expression appeared after 3 h of treatment with IFN-gamma and LPS. Interestingly, mRNA and protein expression of iNOS was down-regulated by sodium nitroprusside (SNP) and diethylamine dinitric oxide in a time- and dose-dependent manner, but not by H2O2. TNF-alpha gene expression was also dramatically reduced by SNP, but IL-6 gene expression was inhibited much less. IFN-gamma and LPS-induced chloramphenicol acetyltransferase activity of iNOS promoter constructs was inhibited by SNP. Electrophoretic mobility shift assay showed that SNP inhibited IFN-gamma plus LPS-induced Oct-1 binding activity, and the inhibition was reversed by DTT. Mutation in the Oct-1 site completely abolished iNOS promoter activity. In addition, supershift assay and Southwestern analysis demonstrated that the Oct-1 binding activity was inhibited by SNP. Taken together, these results indicate that NO suppresses IFN-gamma plus LPS-induced iNOS expression, and that Oct-1 is an important element in this process.
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PMID:Octamer binding protein-1 is involved in inhibition of inducible nitric oxide synthase expression by exogenous nitric oxide in murine liver cells. 1113 60

We describe here a specific and sensitive assay for biologically active bovine type-I interferon (IFN) in an Mx/CAT reporter gene assay. The assay is based on Madin-Darby Bovine Kidney cells transfected with a plasmid, containing a human MxA promoter driving a chloramphenicol acetyltransferase (CAT) cDNA. CAT expression was quantified in a commercially available enzyme linked immunosorbant assay. The response to recombinant bovine INF-alpha(1) was dose dependent between 0.25 and 125.0 iu/ml and was shown to be specific for type-I IFN as no significant effect was seen with a number of other cytokines, including IFN-gamma. This Mx/CAT reporter assay also has advantages in terms of simplicity and reliability over conventional cytopathic effect reduction assays used to quantify the IFN activity in bovine samples. The Mx/CAT reporter assay was used successfully to measure trophoblast derived type-1 IFN activity (IFN-tau) in uterine flushings collected from pregnant cows. IFN-tau is the pregnancy recognition signal produced in ruminants by pre-implantation embryos and was shown to increase markedly between the 12th (0.7+/-0.14 iu/ml) and 18th (44085.0+/-14414.2 iu/ml) day of pregnancy. In contrast, IFN-tau activity remained basal (0.5-0.7 iu/ml) in inseminated non-pregnant animals. Duplicate samples analysed using a cytopathic effect reduction assay correlated well (P<0.001; r(2)=0.945) with IFN levels obtained using the Mx/CAT reporter assay, confirming the reporter assay as a reliable substitute for the standard anti-viral IFN assay.
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PMID:Validation of an Mx/CAT reporter gene assay for the quantification of bovine type-I interferon. 1122 80


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