Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: UNIPROT:P51532 (transcriptional activator)
6,546 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Acquired immunodeficiency syndrome (AIDS) results from infection with a human immunodeficiency virus (HIV). The long terminal repeat (LTR) region of HIV proviral DNA contains binding sites for nuclear factor kappa B (NF-kappa B), and this transcriptional activator appears to regulate HIV activation. Recent findings suggest an involvement of reactive oxygen species (ROS) in signal transduction pathways leading to NF-kappa B activation. The present study was based on reports that antioxidants which eliminate ROS should block the activation of NF-kappa B and subsequently HIV transcription, and thus antioxidants can be used as therapeutic agents for AIDS. Incubation of Jurkat T cells (1 x 10(6) cells/ml) with a natural thiol antioxidant, alpha-lipoic acid, prior to the stimulation of cells was found to inhibit NF-kappa B activation induced by tumor necrosis factor-alpha (25 ng/ml) or by phorbol 12-myristate 13-acetate (50 ng/ml). The inhibitory action of alpha-lipoic acid was found to be very potent as only 4 mM was needed for a complete inhibition, whereas 20 mM was required for N-acetylcysteine. These results indicate that alpha-lipoic acid may be effective in AIDS therapeutics.
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PMID:Alpha-lipoic acid is a potent inhibitor of NF-kappa B activation in human T cells. 148 76

Expression of the Type I IFN (i.e., IFN-alpha s and IFN-beta) genes is efficiently induced by viruses at the transcriptional level. This induction is mediated by at least two types of positive regulatory elements located in the human IFN-beta gene promoter: (1) the repeated elements which bind both the transcriptional activator IRF-1 and the repressor IRF-2 (IRF-elements; IRF-Es), and (2) the kappa B element (kappa B-E), which binds NF kappa B and is located between the IRF-Es and the TATA box. In this study we demonstrate that a promoter containing synthetic IRF-E, which displays high affinity for the IRFs can be efficiently activated by Newcastle disease virus (NDV). In contrast, such activation was either very weak or nil when cells were treated by IFN-beta or tumor necrosis factor-alpha (TNF-alpha), despite the fact they both efficiently induce de novo synthesis of the short-lived IRF-1 in L929 cells. In fact, efficient activation of the IRF-E apparently requires an event in addition to de novo IRF-1 induction, which can be elicited by NDV even in the presence of protein synthesis inhibitor, cycloheximide. Moreover, efficient activation of the IRF-E by NDV is specifically inhibited by the protein kinase inhibitor, Staurosporin. Hence our results suggest the importance of IRF-1 synthesis and post-translational modification event(s), possibly phosphorylation for the efficient activation of IRF-Es, which are otherwise under negative regulation by IRF-2.
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PMID:Activation of IFN-beta element by IRF-1 requires a posttranslational event in addition to IRF-1 synthesis. 188 66

Transcription of the vascular cell adhesion molecule-1 (VCAM-1) gene in endothelial cells is induced by the inflammatory cytokines interleukin-1 beta, tumor necrosis factor-alpha, and lipopolysaccharide. Previous studies demonstrated that the cytokine-response region in the VCAM1 promoter contains binding sites for the transcription factors nuclear factor-kappa B (NF-kappa B) and interferon regulatory factor-1. Using a saturation mutagenesis approach, we report that the cytokine-inducible enhancer consists of these previously characterized elements and a novel region located 3' of the NF-kappa B sites. Electrophoretic mobility shift assays and DNase I footprint studies with endothelial nuclear extracts and recombinant protein revealed that the transcriptional activator Sp1 interacts with this novel element in a specific manner. Transient transfection assays using vascular endothelial cells revealed that site-directed mutations in the Sp1 binding element decreased tumor necrosis factor-alpha-induced activity of the VCAM1 promoter. The cytokine-induced enhancer of the VCAM1 gene requires constitutively bound Sp1 and induced heterodimeric NF-kappa B for maximal promoter activity.
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PMID:Sp1 is a component of the cytokine-inducible enhancer in the promoter of vascular cell adhesion molecule-1. 749 19

Apoptosis is an important regulatory process during normal development and maturation. We find that the proliferation-arresting and differentiation-inducing compound sodium n-butyrate (NaB) triggers a marked host chromatin degradation. This apoptotic process is independent of, but commensurate with, a rapid increase in viral mRNA synthesis and subsequent release of HIV-1 virus in transformed human cell lines harboring tat- (HLM1) or tat+ (U1, ACH-2) dormant HIV-1 proviruses. This compound stimulates a reversible accumulation of the characteristic viral mRNAs at a much faster rate than two other DNA degradation inducers such as tumor necrosis factor-alpha and phorbol 12-myristate 13-acetate. The transcriptional activator butyrate analogue, alpha-amino-n-butyrate, failed to cause similar phenotypic changes. These results suggest that common regulatory signals may be involved in activation of apoptosis genes and latent provirus by NaB.
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PMID:Induction of developmentally programmed cell death and activation of HIV by sodium butyrate. 800 66

The yeast-based two hybrid system has been used to determine whether oligomerization of the intracellular domain of the 55-kDa type 1 tumor necrosis factor (TNF) receptor may occur during TNF action. This assay depends upon reconstitution of the function of the GAL4 transcriptional activator through interaction of a protein fused to the GAL4 DNA binding domain with a protein fused to the transcriptional activation domain of GAL4. Fusion of the type 1 TNF receptor intracellular domain with the DNA binding domain and the transactivation domain of GAL4 led to activation of the lacZ indicator gene, demonstrating interaction of the receptor intracellular domain with itself. A HeLa cell cDNA library was searched for proteins that interact with the intracellular domain of the type 1 TNF receptor. A protein corresponding to amino acids 329-426 in the type 1 TNF receptor intracellular domain was identified by this screen. The aggregation domain was further defined by testing the ability of deletion mutants of the type 1 TNF receptor intracellular region to interact with the complete intracellular domain. These experiments map the aggregation domain to a sequence of amino acids previously shown to be responsible for mediating TNF-induced cytotoxicity. These results suggest that aggregation of type 1 TNF receptor intracellular domains may be important in TNF signal transduction.
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PMID:Aggregation of the intracellular domain of the type 1 tumor necrosis factor receptor defined by the two-hybrid system. 807 96

Inflammatory cytokines may participate in the destruction of pancreatic islets during the pathogenesis of insulin-dependent diabetes mellitus, and the cytokine interleukin-1 (IL-1) strongly inhibits insulin secretion from rat pancreatic islets by a process which involves induction of expression of the inducible isoform of nitric oxide synthase and the overproduction of nitric oxide. The signaling events between IL-1 receptor occupancy and induction of nitric oxide synthase in rat islets involve activation of the transcriptional activator NFkappa B. Because sphingomyelin hydrolysis has been implicated as a signaling process both in NFkappa B activation and in IL-1 action in some cells, we have examined the potential involvement of sphingomyelin hydrolysis in the induction of islet nitric oxide overproduction by IL-1. Rat islet sphingomyelin pools were radiolabeled with [3H]choline, and sphingomyelin was then isolated by normal phase HPLC. Electrospray ionization-mass spectrometric analysis revealed islet sphingomyelin consists of at least 4 distinct molecular species, and the most abundant of them contained sphingosine as the long chain base and a residue of palmitic acid as the fatty acid substituent. Molecular species containing residues of stearic acid and arachidic acid were also observed. Neither interleukin-1 nor tumor necrosis factor-alpha was found to induce hydrolysis of islet sphingomyelin species, and neither an exogenous, cell-permeant ceramide species (N-acetyl-D-sphingosine) nor exogenous sphingomyelinase mimicked or potentiated the effect of IL-1 to increase rat islet nitric oxide generation, as reflected by nitrite production. Similar findings were obtained with RINm5F insulinoma cells and with mouse pancreatic islets. These findings provide the first information on the molecular species of sphingomyelin in pancreatic islets and suggest that sphingomyelin hydrolysis is not involved in the signaling pathway whereby IL-1 induces the overproduction of nitric oxide by pancreatic islets.
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PMID:Characterization of the sphingomyelin content of isolated pancreatic islets. Evaluation of the role of sphingomyelin hydrolysis in the action of interleukin-1 to induce islet overproduction of nitric oxide. 860 64

A novel cDNA, TR2L, isolated from murine NIH 3T3 fibroblasts, was found to modulate tumor necrosis factor (TNF)-mediated apoptosis in murine L929 fibrosarcoma cells. The full-length cDNA (853 bp) encodes a predicted coding region of 56 amino acids (6.3 kD), with 53.6% identity to the C-terminus of rat transcriptional activator FE65. When expressed stably in L929 cells, TR2L protein inhibited TNF cytotoxic response. In contrast, TR2L enhanced anti-Fas antibodies/actinomycin D (ActD)-mediated L929 apoptosis. Alteration of TR2L function occurred by tagging this protein with a 6xHis fragment to the N-terminus (designated 6xH-TR2L). L929 cells which stably expressed 6xH-TR2L acquired a significantly enhanced TNF apoptotic response and increased genomic DNA fragmentation compared to control cells. Enhanced cell death also occurred in these 6xH-TR2L-expressing cells under serum starvation conditions. In contrast, the anti-Fas/ActD-mediated apoptosis was blocked by the 6xH-TR2L protein. Functional role of TR2L protein in regulation of cancer cell susceptibility to TNF-and Fas ligand-mediated apoptosis is suggested.
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PMID:Regulation of tumor necrosis factor-and Fas-mediated apoptotic cell death by a novel cDNA TR2L. 885 35

Interferon (IFN)-gamma increases the sensitivity of tumor cell lines, many of which are p53 mutants, to tumor necrosis factor-alpha-mediated and anti-Fas antibody-mediated cell death. To better understand the mechanism of IFN-gamma action in modulating the cell death response independently of p53 function, we analyzed the death of the human colon adenocarcinoma cell line, HT-29, following treatment with IFN-gamma and various cytotoxic agents. Here we show that IFN-gamma modulates cell death by sensitizing the cells to killing by numerous pro-apoptotic stimuli but not pro-necrotic stimuli. Furthermore, we show that select genes from several important apoptosis-related gene families are induced by IFN-gamma, including the apoptosis-signaling receptors CD95 (Fas/APO-1) and TNFR 1 and interleukin-1beta-converting enzyme (Ice) family members Ice, CPP32 (Yama, apopain), ICErel-II (TX, Ich-2), Mch-3 (ICE-LAP3, CMH-1), Mch-4, and Mch-5 (MACH, FLICE). Of the bcl-2 family members, IFN-gamma directly induced bak but notably not bax, which is activated by p53. The IFN-responsive transcriptional activator interferon regulatory factor-1 was also strongly induced and translocated into the nucleus following IFN-gamma treatment. We propose that IFN-gamma modulates a p53-independent apoptotic pathway by both directly and indirectly inducing select apoptosis-related genes.
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PMID:Interferon-gamma modulates a p53-independent apoptotic pathway and apoptosis-related gene expression. 919 41

Mechanical forces and biochemical stimuli may interact to regulate cellular responses. In this study, we tested the hypothesis that very small mechanical strains interact with growth factors in the regulation of matrix metalloproteinase (MMP)-1. Human vascular smooth muscle cells (VSMCs) were cultured on a precoated silicone membrane in a device that imposes a highly uniform biaxial strain. VSMCs cultured on fibronectin were treated with cyclic 1-Hz strains of 0, 1, or 4%, and MMPs were assayed by Western analysis or gelatin zymography. Small strains did not induce MMP-1 in VSMCs, but strain was a potent inhibitor of platelet-derived growth factor (PDGF)- or tumor necrosis factor-alpha-induced synthesis of MMP-1. In contrast, MMP-2 and TIMP-2 levels were not changed by PDGF and/or mechanical strain. VSMCs strained on the 120-kDa chymotryptic fragment of fibronectin or RGD peptides suppressed PDGF-induced expression of MMP-1, indicating that this effect is not mediated by the heparin-binding domain or connecting segment-1 of fibronectin. Northern analysis of ets-1, a transcriptional activator of MMP-1 expression, showed that strain down-regulated ets-1 expression, whereas c-fos expression was augmented. Thus, small deformations can selectively suppress MMP-1 synthesis by VSMCs, demonstrating the exquisite sensitivity of the cell to mechanical stimuli.
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PMID:Small mechanical strains selectively suppress matrix metalloproteinase-1 expression by human vascular smooth muscle cells. 949 91

The X gene product of the human hepatitis B virus (HBx) is a transcriptional activator of various viral and cellular genes. We recently have determined that the production of tumor necrosis factor-alpha (TNF-alpha) by HBV-infected hepatocytes is transcriptionally up-regulated by HBx, involving nuclear factor of activated T cells (NF-AT)-dependent activation of the TNF-alpha gene promoter. Here we show that HBx activates NF-AT by a cyclosporin A-sensitive mechanism involving dephosphorylation and nuclear translocation of the transcription factor. Luciferase gene expression assays demonstrated that HBx transactivates transcription through NF-AT-binding sites and activates a Gal4-NF-AT chimeric protein. DNA-protein interaction assays revealed that HBx induces the formation of NF-AT-containing DNA-binding complexes. Immunofluorescence analysis demonstrated that HBx induces the nuclear translocation of NF-AT, which can be blocked by the immunosuppressive drug cyclosporin A. Furthermore, immunoblot analysis showed that the HBx-induced activation and translocation of NF-AT are associated with its dephosphorylation. Thus, HBx may play a relevant role in the intrahepatic inflammatory processes by inducing locally the expression of cytokines that are regulated by NF-AT.
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PMID:The hepatitis B virus X protein activates nuclear factor of activated T cells (NF-AT) by a cyclosporin A-sensitive pathway. 984 11


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