101
|
Nourbakhsh M, Kalble S, Dorrie A, Hauser H, Resch K, Kracht M. The NF-kappa b repressing factor is involved in basal repression and interleukin (IL)-1-induced activation of IL-8 transcription by binding to a conserved NF-kappa b-flanking sequence element. J Biol Chem 2001; 276:4501-8. [PMID: 11071890 DOI: 10.1074/jbc.m007532200] [Citation(s) in RCA: 100] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Interleukin (IL)-8, a prototypic chemokine, is rapidly induced by the pro-inflammatory cytokine IL-1 but is barely detectable in noninduced cells. Although there is clear evidence that the transcription factor NF-kappaB plays a central role in inducible IL-8 transcription, very little is known about the cis-elements and trans-acting factors involved in silencing of the IL-8 promoter. By sequence comparison with the interferon-beta promoter, we found a negative regulatory element (NRE) in the IL-8 promoter overlapping partially with the NF-kappaB response element. Here we show that an NF-kappaB-repressing factor (NRF) binds to the IL-8 promoter NF-kappaB-NRE. Reduction of cellular NRF by expressing NRF antisense RNA results in spontaneous IL-8 gene expression. In contrast, IL-1-induced IL-8 secretion is strongly impaired by expressing NRF antisense RNA. Mutation of the NRE site results in loss of NRF binding and increased basal IL-8 transcription. On the other hand IL-1-induced IL-8 transcription is decreased by mutating the NRE. These data provide evidence for a dual role of the NRF in IL-8 transcription. Although in the absence of stimulation it is involved in transcriptional silencing, in IL-1-induced cells it is required for full induction of the IL-8 promoter.
Collapse
Affiliation(s)
- M Nourbakhsh
- Department of Gene Regulation and Differentiation, GBF-National Research Institute for Biotechnology, Mascheroder Weg 1, D-38124 Braunschweig, Germany
| | | | | | | | | | | |
Collapse
|
102
|
Dalbiès-Tran R, Stigger-Rosser E, Dotson T, Sample CE. Amino acids of Epstein-Barr virus nuclear antigen 3A essential for repression of Jkappa-mediated transcription and their evolutionary conservation. J Virol 2001; 75:90-9. [PMID: 11119577 PMCID: PMC113901 DOI: 10.1128/jvi.75.1.90-99.2001] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Epstein-Barr virus (EBV) nuclear antigen 3A (EBNA-3A) is essential for virus-mediated immortalization of B lymphocytes in vitro and is believed to regulate transcription of cellular and/or viral genes. One known mechanism of regulation is through its interaction with the cellular transcription factor Jkappa. This interaction downregulates transcription mediated by EBNA-2 and Jkappa. To identify the amino acids that play a role in this interaction, we have generated mutant EBNA-3A proteins. A mutant EBNA-3A protein in which alanine residues were substituted for amino acids 199, 200, and 202 no longer downregulated transcription. Surprisingly, this mutant protein remained able to coimmunoprecipitate with Jkappa. Using a reporter gene assay based on the recruitment of Jkappa by various regions spanning EBNA-3A, we have shown that this mutation abolished binding of Jkappa to the N-proximal region (amino acids 125 to 222) and that no other region of EBNA-3A alone was sufficient to mediate an association with Jkappa. To determine the biological significance of the interaction of EBNA-3A with Jkappa, we have studied its conservation in the simian lymphocryptovirus herpesvirus papio (HVP) by cloning HVP-3A, the homolog of EBNA-3A encoded by this virus. This 903-amino-acid protein exhibited 37% identity with its EBV counterpart, mainly within the amino-terminal half. HVP-3A also interacted with Jkappa through a region located between amino acids 127 and 223 and also repressed transcription mediated through EBNA-2 and Jkappa. The evolutionary conservation of this function, in proteins that have otherwise significantly diverged, argues strongly for an important biological role in virus-mediated immortalization of B lymphocytes.
Collapse
Affiliation(s)
- R Dalbiès-Tran
- Program in Viral Oncogenesis and Tumor Immunology, Department of Virology and Molecular Biology, St. Jude Children's Research Hospital, Memphis, Tennessee 38105, USA
| | | | | | | |
Collapse
|
103
|
Vandermeeren M, Janssens S, Wouters H, Borghmans I, Borgers M, Beyaert R, Geysen J. Dimethylfumarate is an inhibitor of cytokine-induced nuclear translocation of NF-kappa B1, but not RelA in normal human dermal fibroblast cells. J Invest Dermatol 2001; 116:124-30. [PMID: 11168807 DOI: 10.1046/j.1523-1747.2001.00211.x] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
We previously demonstrated that the oral antipsoriatic dimethylfumarate is an inhibitor of cytokine-induced adhesion molecule expression in endothelial HUVEC cells. We now report the inhibitory effect of dimethylfumarate on tumor-necrosis-factor-alpha- or interleukin-1 alpha-induced intercellular adhesion molecule 1 expression in normal human dermal fibroblasts. Western blots of normal human dermal fibroblast cytoplasmic extracts showed that dimethylfumarate has minor effects on the I kappa B alpha, beta and epsilon proteins: their cytokine-induced degradation and resynthesis is only slowed down, an effect most prominently observed for I kappa B beta. No inhibitory effect of dimethylfumarate was observed on cytokine-induced RelA/p65 or c-Rel accumulation in nuclear extracts of cytokine-treated normal human dermal fibroblast cells. In contrast, cytokine-induced nuclear factor kappa B1/p50 nuclear accumulation was specifically inhibited by dimethylfumarate. This inhibitory effect on nuclear factor kappa B1 nuclear localization in normal human dermal fibroblasts proved sufficient to inhibit nuclear factor kappa B1-RelA binding to nuclear factor kappa B consensus oligonucleotides in DNA binding assays. Likewise, cytokine-induced activation of a pNF kappa B::luciferase reporter construct in transiently transfected normal human dermal fibroblasts was inhibited by dimethylfumarate. The observations support a mechanistic model for the oral antipsoriatic dimethylfumarate in which lowering of nuclear factor kappa B1 leads to changes in the nuclear factor kappa B1-RelA nuclear balance and inhibition of cytokine-induced adhesion molecule expression in normal human dermal fibroblasts.
Collapse
|
104
|
Vanden Berghe W, Vermeulen L, De Wilde G, De Bosscher K, Boone E, Haegeman G. Signal transduction by tumor necrosis factor and gene regulation of the inflammatory cytokine interleukin-6. Biochem Pharmacol 2000; 60:1185-95. [PMID: 11007957 DOI: 10.1016/s0006-2952(00)00412-3] [Citation(s) in RCA: 229] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Interleukin (IL)-6 is a multifunctional cytokine that can be induced by a plethora of chemical or physiological compounds, including the inflammatory cytokines tumor necrosis factor (TNF) and IL-1. The molecule TNF has a trimeric configuration and thus binds to membrane-bound, cellular receptors to initiate cell death mechanisms and signaling pathways leading to gene induction. Previously, we showed that induced clustering of the intracellular domains of the p55 TNF receptor, or of their respective 'death domains' only, is sufficient to activate the nuclear factor kappa B (NF-kappa B) and several mitogen-activated protein kinase (MAPK) pathways. NF-kappa B is the exclusive transcription factor for induction of the IL-6 gene in response to TNF and functions as the final trigger to activate a multiprotein complex, a so-called 'enhanceosome', at the level of the IL-6 promoter. Furthermore, the enhanceosome displays histone acetylation activity, which turned out to be essential for IL-6 gene activation via NF-kappa B. However, activation of NF-kappa B alone is not sufficient for IL-6 gene induction in response to TNF, as inhibition of the coactivated extracellular signal-regulated kinase and p38 MAPK pathways blocks TNF-mediated gene expression. Nevertheless, the transactivating NF-kappa B subunit p65 is not a direct target of MAPK phosphorylation. Thus, we postulated that other components of the enhanceosome complex are sensitive to MAPK cascades and found that MAPK activity is unequivocally linked to the histone acetylation capacity of the enhanceosome to stimulate gene expression in response to TNF. In contrast, glucocorticoid repression of TNF-driven IL-6 gene expression does not depend on abrogation of histone acetyltransferase activity, but originates from interference of the liganded glucocorticoid receptor with the contacts between NF-kappa B p65 and the promoter configuration around the TATA box.
Collapse
Affiliation(s)
- W Vanden Berghe
- Department of Molecular Biology, Flanders Interuniversity Institute for Biotechnology, 9000 Ghent, Belgium
| | | | | | | | | | | |
Collapse
|
105
|
Wu CJ, Yang XF, McLaughlin S, Neuberg D, Canning C, Stein B, Alyea EP, Soiffer RJ, Dranoff G, Ritz J. Detection of a potent humoral response associated with immune-induced remission of chronic myelogenous leukemia. J Clin Invest 2000; 106:705-14. [PMID: 10974024 PMCID: PMC381287 DOI: 10.1172/jci10196] [Citation(s) in RCA: 104] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
The effectiveness of donor-lymphocyte infusion (DLI) for treatment of relapsed chronic myelogenous leukemia (CML) after allogeneic bone marrow transplantation is a clear demonstration of the graft-versus-leukemia (GVL) effect. T cells are critical mediators of GVL, but the antigenic targets of this response are unknown. To determine whether patients who respond to DLI also develop B-cell immunity to CML-associated antigens, we analyzed sera from three patients with relapsed CML who achieved a complete molecular remission after infusion of donor T cells. Sera from these individuals recognized 13 distinct gene products represented in a CML-derived cDNA library. Two proteins, Jkappa-recombination signal-binding protein (RBP-Jkappa) and related adhesion focal tyrosine kinase (RAFTK), were recognized by sera from three of 19 DLI responders. None of these antigens were recognized by sera from healthy donors or patients with chronic graft-versus-host disease. Four gene products were recognized by sera from CML patients treated with hydroxyurea and nine were detected by sera from CML patients who responded to IFN-alpha. Antibody titers specific for RAFTK, but not for RBP-Jkappa, were found to be temporally associated with the response to DLI. These results demonstrate that patients who respond to DLI generate potent antibody responses to CML-associated antigens, suggesting the development of coordinated T- and B-cell immunity. The characterization of B cell-defined antigens may help identify clinically relevant targets of the GVL response in vivo.
Collapse
MESH Headings
- Antibodies, Neoplasm/blood
- B-Lymphocytes/immunology
- DNA-Binding Proteins/immunology
- Focal Adhesion Kinase 2
- Gene Library
- Graft vs Leukemia Effect
- Humans
- Immunoglobulin J Recombination Signal Sequence-Binding Protein
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/genetics
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/immunology
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/therapy
- Lymphocyte Transfusion
- Molecular Sequence Data
- Nuclear Proteins
- Protein-Tyrosine Kinases/immunology
- Remission Induction
- Sequence Analysis, DNA
- T-Lymphocytes/immunology
Collapse
Affiliation(s)
- C J Wu
- Center for Hematologic Oncology, and. Department of Biostatistical Science, Dana-Farber Cancer Institute, and. Department of Medicine, and Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | | | | | | | | | | | | | | | | | | |
Collapse
|
106
|
Legrand-Poels S, Schoonbroodt S, Piette J. Regulation of interleukin-6 gene expression by pro-inflammatory cytokines in a colon cancer cell line. Biochem J 2000; 349 Pt 3:765-73. [PMID: 10903137 PMCID: PMC1221203 DOI: 10.1042/bj3490765] [Citation(s) in RCA: 69] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The two carcinoma cell lines HeLa and HTM-29 show different behaviour in terms of interleukin-6 (IL-6) production. Analyses of secreted IL-6 by ELISA and of IL-6 mRNA by reverse transcription-PCR revealed that, whereas HeLa cells produced high levels of IL-6 in response to tumour necrosis factor-alpha (TNF-alpha) and IL-1beta, the HTM-29 cell line failed to produce both IL-6 protein and mRNA. Nevertheless, the transcription factors nuclear factor-kappaB (NF-kappaB) and NF-IL6, the main factors involved in IL-6 gene transcriptional activation by cytokines, were activated in both cell lines after treatment with TNF-alpha or IL-1beta. In order to verify that the lack of IL-6 expression in HTM-29 cells was not due to an endogenous IL-6 gene deficiency or to IL-6 mRNA instability, we carried out transient transfection assays with an IL-6 promoter-reporter construct. Strong activation of the IL-6 promoter by cytokines could be observed in HeLa cells, whereas no induction could be detected in cytokine-treated HTM-29 cells. These cytokines induced a very strong stimulation of NF-kappaB-mediated transcription in HeLa cells transfected with a kappaB luceriferase reporter construct, whereas no induction could be detected in cytokine-stimulated HTM-29 cells. Thus IL-6 promoter repression in HTM-29 cells probably results from a failure of cytokine-activated NF-kappaB to exert its transactivating activities. Western blotting experiments demonstrated that the lack of NF-kappaB-mediated transcription was not due to increased expression of IkappaB (inhibitor of NF-kappaB) proteins in HTM-29 cells. Co-transfection experiments with the kappaB Luc reporter construct and the CBP [CREB (cAMP response element binding protein) binding protein] expression vector showed that the impairment in NF-kappaB-dependent transcription did not result from a deficiency in the co-activator CBP. Interestingly, both NF-kappaB-mediated transcription and IL-6 promoter activation could be restored in HTM-29 cells by transfection with RelA. Furthermore, CBP could have a significant synergistic effect on exogenous RelA-mediated transcription. Since sequencing of the endogenous relA gene did not reveal any mutation, it is likely that repression of NF-kappaB-mediated transcription results from negative cross-talk between NF-kappaB and another nuclear factor specifically expressed or regulated by TNF-alpha in HTM-29 cells.
Collapse
Affiliation(s)
- S Legrand-Poels
- Laboratory of Virology & Immunology, Institute of Pathology B23, University of Liège, B-4000 Liège, Belgium
| | | | | |
Collapse
|
107
|
Lee SH, Wang X, DeJong J. Functional interactions between an atypical NF-kappaB site from the rat CYP2B1 promoter and the transcriptional repressor RBP-Jkappa/CBF1. Nucleic Acids Res 2000; 28:2091-8. [PMID: 10773077 PMCID: PMC105370 DOI: 10.1093/nar/28.10.2091] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The phenobarbital-inducible rat cytochrome P450 (CYP) 2B1 and 2B2 proteins are encoded by homologous genes whose promoters contain a mammalian-apparent long terminal repeat retrotransposon (MaLR). An NF-kappaB-like site within the MaLR forms multiple protein-DNA complexes with rat liver and HeLa cell nuclear extracts. Using antibody supershift assays, we have identified these complexes as NF-kappaB and RPB-Jkappa/CBF1. Competition assays using a series of single site mutant oligonucleotides reveal that the recognition sites for these two factors overlap. We also show that the CYP2B1/2 NF-kappaB element, but not the Igkappa NF-kappaB element, can repress transcription in vitro when positioned upstream of the heterologous adenovirus major late core promoter. In addition, RBP-Jkappa over-expressed in COS-7 cells repressed expression in vivo from an SV40-luciferase reporter construct that contained the CYP2B1/2 NF-kappaB element. Finally, we observe similar levels of NF-kappaB and RBP-Jkappa binding activities in nuclear extracts prepared from control and phenobarbital-induced rat livers. The results suggest that RBP-Jkappa/CBF1 binds an atypical NF-kappaB site in the CYP2B1/2 promoters and may help to maintain a low level of expression in the absence of inducer.
Collapse
Affiliation(s)
- S H Lee
- Department of Molecular and Cell Biology, The University of Texas at Dallas, 2601 North Floyd Road, Richardson, TX 75080, USA
| | | | | |
Collapse
|
108
|
De Bosscher K, Vanden Berghe W, Vermeulen L, Plaisance S, Boone E, Haegeman G. Glucocorticoids repress NF-kappaB-driven genes by disturbing the interaction of p65 with the basal transcription machinery, irrespective of coactivator levels in the cell. Proc Natl Acad Sci U S A 2000; 97:3919-24. [PMID: 10760263 PMCID: PMC18117 DOI: 10.1073/pnas.97.8.3919] [Citation(s) in RCA: 232] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Glucocorticoids (GCs) are used to combat inflammatory diseases. Their beneficial effect relies mainly on the inhibition of NF-kappaB- and/or AP-1-driven proinflammatory gene expression. Previously, we have shown that GCs repress tumor necrosis factor-induced IL-6 gene expression by an NF-kappaB-dependent nuclear mechanism without changing the DNA-binding capacity of NF-kappaB or the expression levels of the cytoplasmic inhibitor of NF-kappaB (IkappaB-alpha). In the present work, we investigate the effect of GC repression on different natural and/or recombinant NF-kappaB-driven reporter gene constructs in the presence of increasing amounts of various coactivator molecules, such as CREB-binding protein (CBP), p300, and SRC-1. We found that GCs maintain their repressive capacities, irrespective of the amount of cofactor present in the cell. Similar results were obtained for the reciprocal transrepression of a GC receptor (GR) element-driven reporter gene by p65. We demonstrate that neither the expression levels of p65 and CBP nor their physical association are affected by activated GR. Using Gal4 chimeras, we show that repression by GCs is specific for p65-mediated transactivation, ruling out competition for limiting nuclear factors as the major underlying mechanism of gene repression. In addition, the transactivation potential of a point-mutated Gal4-p65 variant with a decreased CBP interaction capability is still repressed by GR. Finally, we present evidence that the specificity of GC repression on p65-driven gene expression is codetermined by the TATA box context.
Collapse
Affiliation(s)
- K De Bosscher
- Department of Molecular Biology, Flanders Interuniversity Institute for Biotechnology and University of Gent, K. L. Ledeganckstraat 35, 9000 Gent, Belgium
| | | | | | | | | | | |
Collapse
|
109
|
Wery-Zennaro S, Zugaza JL, Letourneur M, Bertoglio J, Pierre J. IL-4 regulation of IL-6 production involves Rac/Cdc42- and p38 MAPK-dependent pathways in keratinocytes. Oncogene 2000; 19:1596-604. [PMID: 10734320 DOI: 10.1038/sj.onc.1203458] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The stress-activated pathways leading to activation of p38 MAP kinase (p38 MAPK) and c-jun N-terminal kinases (JNK) have been shown to be activated by pro-inflammatory cytokines, physical and chemical stresses as well as a variety of hematopoietic growth factors. One exception is interleukin (IL)-4, which does not activate this pathway in hematopoietic cell. We report here that in A431, a keratinocytic cell line, IL-4 activates Rac and Cdc42 and their downstream effector p21-activated kinase (PAK). Rac and Cdc42 appear to regulate a protein kinase cascade initiated at the level of PAK and leading to activation of p38 MAPK, since IL-4 stimulates tyrosine phosphorylation of p38 MAPK and increases its catalytic activity. As A431 cells are able to produce IL-6 in response to IL-4 stimulation, we assessed the involvement of p38 MAPK in IL-6 gene expression. A pyrimidazole compound, SB203580, a specific inhibitor of p38 MAPK, inhibits production and gene expression of IL-6. SB203580 reduced significantly the stability of IL-6 mRNA. Here we provide evidence that p38 MAPK is activated in response to IL-4 and is involved in IL-6 synthesis by stabilizing IL-6 mRNA.
Collapse
Affiliation(s)
- S Wery-Zennaro
- INSERM U461, Faculté de Pharmacie, 5, rue J B Clément, 92296 Chätenay-Malabry, Cedex, France
| | | | | | | | | |
Collapse
|
110
|
Krauer KG, Buck M, Sculley T. Characterization of the transcriptional repressor RBP in Epstein-Barr virus-transformed B cells. J Gen Virol 1999; 80 ( Pt 12):3217-3226. [PMID: 10567654 DOI: 10.1099/0022-1317-80-12-3217] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
RBP, a transcriptional repressor, is intricately involved in Epstein-Barr virus (EBV) transformation of human B cells. The EBV nuclear proteins EBNA-2, -3, -4 and -6 all utilize RBP to regulate the transcription of both cellular and viral genes. This study investigates the isoforms of the RBP protein in Burkitt's lymphoma (BL) cells and in EBV-transformed lymphoblastoid cell lines (LCLs). Two-dimensional gel electrophoresis showed the presence of two different cellular isoforms of RBP; the molecular masses and isoelectric points of these two isoforms corresponded to RBP-Jkappa and RBP-2N. Fractionation studies and green fluorescent protein (GFP)-tagged expression studies demonstrated that both RBP isoforms were located predominantly in the cell nucleus. Interestingly, GFP-tagged RBP-Jkappa showed diffuse, uniform nuclear staining, whereas GFP-tagged RBP-2N showed a discrete nuclear pattern, demonstrating differences between the two isoforms. Within the nuclear fraction of EBV-negative BL cells, RBP existed both in a free form and bound to chromatin, whereas in LCLs the intranuclear RBP was predominantly chromatin-bound. Expression of the EBV latent proteins was found to lead to the sequestering of RBP from the cytoplasm into the cell nucleus and to an increase in the chromatin-bound forms of RBP.
Collapse
Affiliation(s)
- Kenia G Krauer
- Queensland Institute of Medical Research and University of Queensland Joint Oncology Program, 300 Herston Road, Herston 4029, Brisbane, Australia1
| | - Marion Buck
- Queensland Institute of Medical Research and University of Queensland Joint Oncology Program, 300 Herston Road, Herston 4029, Brisbane, Australia1
| | - Tom Sculley
- Queensland Institute of Medical Research and University of Queensland Joint Oncology Program, 300 Herston Road, Herston 4029, Brisbane, Australia1
| |
Collapse
|
111
|
Armenante F, Merola M, Furia A, Tovey M, Palmieri M. Interleukin-6 repression is associated with a distinctive chromatin structure of the gene. Nucleic Acids Res 1999; 27:4483-90. [PMID: 10536159 PMCID: PMC148733 DOI: 10.1093/nar/27.22.4483] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Expression of the interleukin-6 (IL-6) gene is usually tightly controlled and may be induced in specific tissues only after treatment with appropriate stimuli. The molecular mechanisms responsible for IL-6 gene repression in specific tissues or cell lines remain poorly defined. In order to address this question we have studied two human breast carcinoma cell lines, MDA-MB-231, in which the IL-6 gene is expressed, and MCF-7, in which it is not. The promoter region of the IL-6 gene was analysed in both cell lines with reference to two different parameters: (i) DNase I hypersensitivity; (ii) the in vivo pattern of DNA-protein interactions. We show herein that the mechanism responsible for silencing IL-6 gene expression in MCF-7 cells most probably involves a modification of chromatin structure, as suggested by a decreased sensitivity of the IL-6 promoter to DNase I relative to the IL-6-expressing cell line MDA-MB-231. Moreover, we show that a 'closed' nucleosomal structure in MCF-7 cells does not inhibit the binding of nuclear proteins to IL-6 gene regulatory sequences in vivo. We suggest, therefore, that, in non-expressing cells, local chromatin remodelling at the proximal promoter is inhibited by negative regulators, as suggested by two specific hallmarks of nuclear factor binding that are not observed in expressing cells: an additional in vivo footprint spanning positions -135/-119 and an additional DNase I hypersensitive site far upstream, around position -1400. Furthermore, a specific factor binding in vitro to the -140/-116 region of the IL-6 promoter is found in MCF-7 cells.
Collapse
Affiliation(s)
- F Armenante
- Dipartimento di Scienze Neurologiche e della Visione, Sezione di Chimica Biologica, Facolta' di Medicina e Chirurgia, Universita' di Verona, Strada le Grazie 8, 37134 Verona, Italy
| | | | | | | | | |
Collapse
|
112
|
Vanden Berghe W, De Bosscher K, Boone E, Plaisance S, Haegeman G. The nuclear factor-kappaB engages CBP/p300 and histone acetyltransferase activity for transcriptional activation of the interleukin-6 gene promoter. J Biol Chem 1999; 274:32091-8. [PMID: 10542243 DOI: 10.1074/jbc.274.45.32091] [Citation(s) in RCA: 273] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Expression of the pleiotropic cytokine interleukin (IL)-6 can be stimulated by the proinflammatory cytokine tumor necrosis factor (TNF) and the microbial alkaloid staurosporine (STS). In this report, the transcriptional mechanisms were thoroughly investigated. Whereas transcription factors binding to the activator protein-1-, cAMP-responsive element-, and CAAT enhancer-binding protein-responsive sequences are necessary for gene activation by STS, nuclear factor (NF)-kappaB alone is responsible and sufficient for inducibility by TNF, which reveals distinct signaling pathways for both compounds. At the cofactor level, cAMP-responsive element-binding protein-binding protein (CBP) or p300 potentiate basal and induced IL-6 promoter activation via multiple protein-protein interactions with all transcription factors bound to the promoter DNA. However, the strongest promoter activation relies on the p65 NF-kappaB subunit, which specifically engages CBP/p300 for maximal transcriptional stimulation by its histone acetyltransferase activity. Moreover, treatment of chromatin-integrated promoter constructions with the histone deacetylase inhibitor trichostatin A exclusively potentiates TNF-dependent (i.e. NF-kappaB-mediated) gene activation, while basal or STS-stimulated IL-6 promoter activity remains completely unchanged. Similar observations were recorded with other natural NF-kappaB-driven promoters, namely IL-8 and endothelial leukocyte adhesion molecule (ELAM). We conclude that, within an "enhanceosome-like" structure, NF-kappaB is the central mediator of TNF-induced IL-6 gene expression, involving CBP/p300 and requiring histone acetyltransferase activity.
Collapse
Affiliation(s)
- W Vanden Berghe
- Department of Molecular Biology, University of Gent and Flanders Interuniversity Institute for Biotechnology, B-9000 Gent, Belgium
| | | | | | | | | |
Collapse
|
113
|
Alen P, Claessens F, Verhoeven G, Rombauts W, Peeters B. The androgen receptor amino-terminal domain plays a key role in p160 coactivator-stimulated gene transcription. Mol Cell Biol 1999; 19:6085-97. [PMID: 10454556 PMCID: PMC84524 DOI: 10.1128/mcb.19.9.6085] [Citation(s) in RCA: 209] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/1999] [Accepted: 05/11/1999] [Indexed: 01/08/2023] Open
Abstract
Steroid receptors are conditional transcription factors that, upon binding to their response elements, regulate the expression of target genes via direct protein interactions with transcriptional coactivators. We have analyzed the functional interactions between the androgen receptor (AR) and 160-kDa nuclear receptor coactivators. Upon overexpression in mammalian cells, these coactivators enhance the transcriptional activity of both the amino-terminal domain (NTD) and the ligand-binding domain (LBD) of the AR. The coactivator activity for the LBD is strictly ligand-controlled and depends on the nature of the DNA-binding domain to which it is fused. We demonstrate that the NTD physically interacts with coactivators and with the LBD and that this interaction, like the functional interaction between the LBD and p160 coactivators, relies on the activation function 2 (AF2) core domain. The mutation of a highly conserved lysine residue in the predicted helix 3 of the LBD (K720A), however, blunts the functional interaction with coactivators but not with the NTD. Moreover, this mutation does not affect the transcriptional activity of the full-size AR. A mutation in the NTD of activation function AF1a (I182A/L183A), which dramatically impairs the activity of the AR, has no effect on the intrinsic transcriptional activity of the NTD but interferes with the cooperation between the NTD and the LBD. Finally, p160 proteins in which the three LXXLL motifs are mutated retain most of their coactivator activity for the full-size AR, although they are no longer functional for the isolated LBD. Together, these data suggest that in the native AR the efficient recruitment of coactivators requires a functional association of the NTD with the LBD and that the binding of coactivators occurs primarily through the NTD.
Collapse
Affiliation(s)
- P Alen
- Division of Biochemistry, Faculty of Medicine, University of Leuven, B-3000 Leuven, Belgium
| | | | | | | | | |
Collapse
|
114
|
Palmieri M, Sasso MP, Monese R, Merola M, Faggioli L, Tovey M, Furia A. Interaction of the nuclear protein CBF1 with the kappaB site of the IL-6 gene promoter. Nucleic Acids Res 1999; 27:2785-91. [PMID: 10373597 PMCID: PMC148489 DOI: 10.1093/nar/27.13.2785] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The nuclear protein CBF1 has been shown to function as an intermediate to target transcription factors,such as the activated Notch receptor,to specific DNA sites. In this paper,we show that CBF1 from cell lines of different origin is able to bind to the[kappa]B site of the IL-6 promoter. By transfection analyses performed in HeLa cells,we demonstrate that overexpressed CBF1 acts as a negative regulator of IL-6 gene transcription and is unable to elicit Notch-dependent activation of this gene. Analyses of protein-DNA interactions indicate that the topology of the complex formed by CBF1 and the target DNA is subtly affected by sequencessurrounding the recognition site. Furthermore,we show that CBF1 induces DNA bending. This finding suggests that CBF1 may influence IL-6 gene transcription by determining a specific conformation of the promoter region.
Collapse
Affiliation(s)
- M Palmieri
- Dipartimento di Scienze Neurologiche e della Visione, Sezione Biochimica Facoltá di Medicina e Chirurgia, Universita di Verona, Italy
| | | | | | | | | | | | | |
Collapse
|
115
|
Lin RJ, Kao HY, Ordentlich P, Evans RM. The transcriptional basis of steroid physiology. COLD SPRING HARBOR SYMPOSIA ON QUANTITATIVE BIOLOGY 1999; 63:577-85. [PMID: 10384323 DOI: 10.1101/sqb.1998.63.577] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Affiliation(s)
- R J Lin
- Howard Hughes Medical Institute, Salk Institute for Biological Studies, La Jolla, California 92037, USA
| | | | | | | |
Collapse
|
116
|
Heyninck K, De Valck D, Vanden Berghe W, Van Criekinge W, Contreras R, Fiers W, Haegeman G, Beyaert R. The zinc finger protein A20 inhibits TNF-induced NF-kappaB-dependent gene expression by interfering with an RIP- or TRAF2-mediated transactivation signal and directly binds to a novel NF-kappaB-inhibiting protein ABIN. J Cell Biol 1999; 145:1471-82. [PMID: 10385526 PMCID: PMC2133159 DOI: 10.1083/jcb.145.7.1471] [Citation(s) in RCA: 251] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/1998] [Revised: 03/29/1999] [Indexed: 01/28/2023] Open
Abstract
The zinc finger protein A20 is a tumor necrosis factor (TNF)- and interleukin 1 (IL-1)-inducible protein that negatively regulates nuclear factor-kappa B (NF-kappaB)-dependent gene expression. However, the molecular mechanism by which A20 exerts this effect is still unclear. We show that A20 does not inhibit TNF- induced nuclear translocation and DNA binding of NF-kappaB, although it completely prevents the TNF- induced activation of an NF-kappaB-dependent reporter gene, as well as TNF-induced IL-6 and granulocyte macrophage-colony stimulating factor gene expression. Moreover, NF-kappaB activation induced by overexpression of the TNF receptor-associated proteins TNF receptor-associated death domain protein (TRADD), receptor interacting protein (RIP), and TNF recep- tor-associated factor 2 (TRAF2) was also inhibited by expression of A20, whereas NF-kappaB activation induced by overexpression of NF-kappaB-inducing kinase (NIK) or the human T cell leukemia virus type 1 (HTLV-1) Tax was unaffected. These results demonstrate that A20 inhibits NF-kappaB-dependent gene expression by interfering with a novel TNF-induced and RIP- or TRAF2-mediated pathway that is different from the NIK-IkappaB kinase pathway and that is specifically involved in the transactivation of NF-kappaB. Via yeast two-hybrid screening, we found that A20 binds to a novel protein, ABIN, which mimics the NF-kappaB inhibiting effects of A20 upon overexpression, suggesting that the effect of A20 is mediated by its interaction with this NF-kappaB inhibiting protein, ABIN.
Collapse
Affiliation(s)
- K Heyninck
- Department of Molecular Biology, Flanders Interuniversity Institute for Biotechnology, University of Ghent, B-9000 Ghent, Belgium
| | | | | | | | | | | | | | | |
Collapse
|
117
|
George CL, Fantuzzi G, Bursten S, Leer L, Abraham E. Effects of lisofylline on hyperoxia-induced lung injury. THE AMERICAN JOURNAL OF PHYSIOLOGY 1999; 276:L776-85. [PMID: 10330034 DOI: 10.1152/ajplung.1999.276.5.l776] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Lisofylline [1-(5R-hydroxyhexyl)-3,7-dimethylxanthine] decreases lipid peroxidation in vitro and in vivo suppresses proinflammatory cytokine expression in models of lung injury due to sepsis, blood loss, and oxidative damage. In the present experiments, we used a murine hyperoxia model to examine the effects of lisofylline on the activation of nuclear transcriptional regulatory factors [nuclear factor-kappaB and cAMP response element binding protein (CREB)], the expression of proinflammatory cytokines in the lungs, and the circulating levels of oxidized free fatty acids as well as on hyperoxia-induced lung injury and mortality. Treatment with lisofylline inhibited hyperoxia-associated increases in tumor necrosis factor-alpha, interleukin-1beta, and interleukin-6 in the lungs as well as decreased the levels of hyperoxia-induced serum-oxidized free fatty acids. Although hyperoxic exposure produced activation of both nuclear factor-kappaB and CREB in lung cell populations, only CREB activation was reduced in the mice treated with lisofylline. Lisofylline diminished hyperoxia-associated increases in lung wet-to-dry weight ratios and improved survival in animals exposed to hyperoxia. These results suggest that lisofylline ameliorates hyperoxia-induced lung injury and mortality through inhibiting CREB activation, membrane oxidation, and proinflammatory cytokine expression in the lungs.
Collapse
Affiliation(s)
- C L George
- Department of Pediatric Critical Care, University of Colorado Health Sciences Center, Denver, Colorado 80262, USA
| | | | | | | | | |
Collapse
|
118
|
|
119
|
|
120
|
Hsieh JJ, Zhou S, Chen L, Young DB, Hayward SD. CIR, a corepressor linking the DNA binding factor CBF1 to the histone deacetylase complex. Proc Natl Acad Sci U S A 1999; 96:23-8. [PMID: 9874765 PMCID: PMC15086 DOI: 10.1073/pnas.96.1.23] [Citation(s) in RCA: 244] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/1998] [Indexed: 11/18/2022] Open
Abstract
CBF1 is a member of the CSL family of DNA binding factors, which mediate either transcriptional repression or transcriptional activation. CSL proteins play a central role in Notch signaling and in Epstein-Barr virus-induced immortalization. Notch is a transmembrane protein involved in cell-fate decisions, and the cytoplasmic domain of Notch (NotchIC) targets CBF1. The Epstein-Barr virus-immortalizing protein EBNA2 activates both cellular and viral gene expression by targeting CBF1 and mimicking NotchIC. We have examined the mechanism of CBF1-mediated repression and show that CBF1 binds to a unique corepressor, CBF1 interacting corepressor (CIR). A CIR homolog is encoded by Caenorhabditis elegans, indicating that CIR is evolutionarily conserved. Two CBF1 mutants that were unable to bind CIR did not function as repressors, suggesting that targeting of CIR to CBF1 is an important component of repression. When expressed as a Gal4 fusion protein, CIR repressed reporter gene expression. CIR binds to histone deacetylase and to SAP30 and serves as a linker between CBF1 and the histone deacetylase complex.
Collapse
Affiliation(s)
- J J Hsieh
- Molecular Virology Laboratories, Department of Pharmacology and Molecular Sciences and Department of Oncology, Johns Hopkins School of Medicine, 725 North Wolfe Street, Baltimore, MD 21205, USA
| | | | | | | | | |
Collapse
|
121
|
Krauer KG, Belzer DK, Liaskou D, Buck M, Cross S, Honjo T, Sculley T. Regulation of interleukin-1beta transcription by Epstein-Barr virus involves a number of latent proteins via their interaction with RBP. Virology 1998; 252:418-30. [PMID: 9878621 DOI: 10.1006/viro.1998.9441] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Epstein-Barr virus (EBV) infects B cells, resulting in the outgrowth of immortalised lymphoblastoid cell lines (LCLs). Here, we demonstrate through the use of intracellular staining that interleukin-1beta (IL-1beta) is expressed in LCLs and investigate the influence of the individual latent proteins on the expression of IL-1beta. Using RT-PCR, IL-1beta was shown to be up-regulated in EBV-transformed LCLs as well as in group III Burkitt's lymphoma (BL) cell lines, compared with group I BL cell lines. The up-regulation of IL-1beta message could be mediated by the latent membrane protein-1, EBV nuclear proteins 2, 3, 4, and 6 genes. Electrophoretic mobility shift assays (EMSAs) demonstrated that the -300 region of the IL-1beta promoter, which contains a nuclear factor-kappaB (NF-kappaB) binding site, contained a functional RBP binding site. Binding of RBP to this site could be inhibited by addition of EBV nuclear proteins 3 and 6, suggesting that these proteins displace RBP from its recognition sequence, removing transcriptional repression and allowing gene transcription to occur. In group I BL cells, containing low levels of NF-kappaB, only RBP binding was observed in EMSAs, whereas NF-kappaB binding could be demonstrated in EBV-transformed B cell lines containing high levels of activated NF-kappaB. In addition, the expression of latent membrane protein-1 led to activation of NF-kappaB that was capable of binding the IL-1beta promoter. The study demonstrates that EBV can up-regulate IL-1beta expression, possibly by using RBP, NF-kappaB, or both.
Collapse
Affiliation(s)
- K G Krauer
- The Joint Oncology Program, Queensland Institute of Medical Research, University of Queensland, 300 Herston Road, Herston, Brisbane, 4029, Australia
| | | | | | | | | | | | | |
Collapse
|
122
|
Udalova IA, Knight JC, Vidal V, Nedospasov SA, Kwiatkowski D. Complex NF-kappaB interactions at the distal tumor necrosis factor promoter region in human monocytes. J Biol Chem 1998; 273:21178-86. [PMID: 9694874 DOI: 10.1074/jbc.273.33.21178] [Citation(s) in RCA: 106] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We describe a dense cluster of DNA-protein interactions located 600 nucleotides upstream of the transcriptional start site of the human tumor necrosis factor (TNF) gene. This area was identified as being of potential importance for lipopolysaccharide-inducible TNF expression in the human monocyte cell line Mono Mac 6, based on reporter gene analysis of point mutations at a number of nuclear factor kappaB (NF-kappaB)-like motifs within the human TNF promoter region. The area contains two NF-kappaB sites, which are here shown by DNase I and methylation interference footprinting to flank a novel binding site. UV cross-linking studies reveal that the novel site can also bind NF-kappaB as well as an unknown protein(s) of approximately 40 kDa. We show that these three adjacent kappaB-binding sites differ markedly in their relative affinities for p50/p50, p65/p65, and p65/p50, yet this 39-nucleotide segment of DNA appears capable of binding up to three NF-kappaB heterodimers simultaneously. Reporter gene studies indicate that each element of the cluster contributes to lipopolysaccharide-induced transcriptional activation in Mono Mac 6 cells. These findings suggest that NF-kappaB acts in a complex manner to activate TNF transcription in human monocytes.
Collapse
Affiliation(s)
- I A Udalova
- Oxford University Department of Paediatrics, Institute of Molecular Medicine, John Radcliffe Hospital, Oxford OX3 9DS, United Kingdom.
| | | | | | | | | |
Collapse
|
123
|
Kao HY, Ordentlich P, Koyano-Nakagawa N, Tang Z, Downes M, Kintner CR, Evans RM, Kadesch T. A histone deacetylase corepressor complex regulates the Notch signal transduction pathway. Genes Dev 1998; 12:2269-77. [PMID: 9694793 PMCID: PMC317043 DOI: 10.1101/gad.12.15.2269] [Citation(s) in RCA: 453] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/1998] [Accepted: 06/17/1998] [Indexed: 11/25/2022]
Abstract
The Delta-Notch signal transduction pathway has widespread roles in animal development in which it appears to control cell fate. CBF1/RBP-Jkappa, the mammalian homolog of Drosophila Suppressor of Hairless [Su(H)], switches from a transcriptional repressor to an activator upon Notch activation. The mechanism whereby Notch regulates this switch is not clear. In this report we show that prior to induction CBF1/RBP-Jkappa interacts with a corepressor complex containing SMRT (silencing mediator of retinoid and thyroid hormone receptors) and the histone deacetylase HDAC-1. This complex binds via the CBF1 repression domain, and mutants defective in repression fail to interact with the complex. Activation by Notch disrupts the formation of the repressor complex, thus establishing a molecular basis for the Notch switch. Finally, ESR-1, a Xenopus gene activated by Notch and X-Su(H), is induced in animal caps treated with TSA, an inhibitor of HDAC-1. The functional role for the SMRT/HDAC-1 complex in CBF1/RBP-Jkappa regulation reveals a novel genetic switch in which extracellular ligands control the status of critical nuclear cofactor complexes.
Collapse
Affiliation(s)
- H Y Kao
- Howard Hughes Medical Institute, The Salk Institute for Biological Studies, La Jolla, California 92037 USA
| | | | | | | | | | | | | | | |
Collapse
|
124
|
Olave I, Reinberg D, Vales LD. The mammalian transcriptional repressor RBP (CBF1) targets TFIID and TFIIA to prevent activated transcription. Genes Dev 1998; 12:1621-37. [PMID: 9620850 PMCID: PMC316873 DOI: 10.1101/gad.12.11.1621] [Citation(s) in RCA: 71] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
RBP is a cellular protein that functions as a transcriptional repressor in mammalian cells. RBP has elicited great interest lately because of its established roles in regulating gene expression, in Drosophila and mouse development, and as a component of the Notch signal transduction pathway. This report focuses on the mechanism by which RBP represses transcription and thereby regulates expression of a relatively simple, but natural, promoter. The results show that, irrespective of the close proximity between RBP and other transcription factors bound to the promoter, RBP does not occlude binding by these other transcription factors. Instead, RBP interacts with two transcriptional coactivators: dTAFII110, a subunit of TFIID, and TFIIA to repress transcription. The domain of dTAFII110 targeted by RBP is the same domain that interacts with TFIIA, but is disparate from the domain that interacts with Sp1. Repression can be thwarted when stable transcription preinitiation complexes are formed before RBP addition, suggesting that RBP interaction with TFIIA and TFIID perturbs optimal interactions between these coactivators. Consistent with this, interaction between RBP and TFIIA precludes interaction with dTAFII110. This is the first report of a repressor specifically targeting these two coactivators to subvert activated transcription.
Collapse
Affiliation(s)
- I Olave
- Department of Biochemistry, University of Medicine and Dentistry of New Jersey, Robert Wood Johnson Medical School, Piscataway, New Jersey 08854 USA
| | | | | |
Collapse
|
125
|
Oswald F, Liptay S, Adler G, Schmid RM. NF-kappaB2 is a putative target gene of activated Notch-1 via RBP-Jkappa. Mol Cell Biol 1998; 18:2077-88. [PMID: 9528780 PMCID: PMC121438 DOI: 10.1128/mcb.18.4.2077] [Citation(s) in RCA: 211] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
NF-kappaB2 (p100/p52), a member of the NF-kappaB/Rel family of transcription factors, is involved in the regulation of a variety of genes important for immune function. Previously, we have shown that the NF-kappaB2 gene is regulated in a positive and a negative manner. Two kappaB elements within the NF-kappaB2 promoter mediate tumor necrosis factor alpha-inducible transactivation. In addition, we have shown that there exists a transcriptional repression in the absence of NF-kappaB. To identify a DNA binding activity responsible for this transcriptional repression, we have partially purified a nuclear complex, named Rep-kappaB. Here we further analyze this putative repressive binding activity. Detailed examination of Rep-kappaB-DNA interaction revealed the sequence requirements for binding to be almost identical to those of recombination signal binding protein Jkappa (RBP-Jkappa), the mammalian homolog of the protein encoded by Drosophila suppressor of hairless [Su(H)]. In addition, in electromobility shift assays, Rep-kappaB binding activity is recognized by an antibody directed against RBP-Jkappa. By performing transient-transfection assays, we show that human RBP-Jkappa represses basal as well as RelA (p65)-stimulated NF-kappaB2 promoter activity. Studies in Drosophila melanogaster have shown that Su(H) is implicated in the Notch signaling pathway regulating cell fate decisions. In transient-transfection assays we show that truncated Notch-1 strongly induces NF-kappaB2 promoter activity. In summary, our data clearly demonstrate that Rep-kappaB is closely related or identical to RBP-Jkappa. RBP-Jkappa is a strong transcriptional repressor of NF-kappaB2. Moreover, this repression can be overcome by activated Notch-1, suggesting that NF-kappaB2 is a novel putative Notch target gene.
Collapse
Affiliation(s)
- F Oswald
- Department of Internal Medicine, University of Ulm, Germany
| | | | | | | |
Collapse
|
126
|
Miyazawa K, Mori A, Yamamoto K, Okudaira H. Transcriptional roles of CCAAT/enhancer binding protein-beta, nuclear factor-kappaB, and C-promoter binding factor 1 in interleukin (IL)-1beta-induced IL-6 synthesis by human rheumatoid fibroblast-like synoviocytes. J Biol Chem 1998; 273:7620-7. [PMID: 9516466 DOI: 10.1074/jbc.273.13.7620] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
The involvement of interleukin (IL)-6 in the pathogenesis of rheumatoid arthritis (RA) has been recently demonstrated. IL-1beta stimulated rheumatoid fibroblast-like synoviocytes (FLSs) to produce IL-6 in a concentration- and time-dependent manner. In the present study we investigated how the IL-6 promoter is transcriptionally regulated in rheumatoid FLSs in response to a physiologically relevant mediator of inflammation, IL-1beta. Deletion analysis showed that the IL-6 promoter is regulated by two positive elements (located at -159 to -142 base pairs (bp) and -77 to -59 bp). Electrophoretic mobility shift assays revealed that CCAAT/enhancer binding protein-beta (C/EBPbeta) binding to nucleotides -159 to -142 bp was constitutively present. The probe corresponding to nucleotides -77 to -59 bp gave three positive bands. The two slower migrating bands were induced by IL-1beta and comprised an nuclear factor (NF)-kappaB p50/p65 heterodimer and a p65/p65 homodimer. The faster migrating band was constitutively expressed and identified as Epstein-Barr virus C-promoter binding factor 1, CBF1. Site-specific mutagenesis analysis demonstrated that the NF-kappaB and CBF1 binding elements regulated inducible activity of the IL-6 promoter in response to IL-1beta stimulation, whereas the C/EBPbeta binding element mainly regulated basal activity. We also provide the first evidence that CBF1 functions as a positive regulator of human IL-6 gene transcription.
Collapse
Affiliation(s)
- K Miyazawa
- Department of Medicine and Physical Therapy, Faculty of Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | | | | | | |
Collapse
|
127
|
Vanden Berghe W, Plaisance S, Boone E, De Bosscher K, Schmitz ML, Fiers W, Haegeman G. p38 and extracellular signal-regulated kinase mitogen-activated protein kinase pathways are required for nuclear factor-kappaB p65 transactivation mediated by tumor necrosis factor. J Biol Chem 1998; 273:3285-90. [PMID: 9452444 DOI: 10.1074/jbc.273.6.3285] [Citation(s) in RCA: 584] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Interleukin-6 (IL-6) is a pleiotropic cytokine, which is involved in inflammatory and immune responses, acute phase reactions, and hematopoiesis. In the mouse fibrosarcoma cell line L929, the nuclear factor (NF)-kappaB plays a crucial role in IL-6 gene expression mediated by tumor necrosis factor (TNF). The levels of the activated factor do not, however, correlate with the variations of IL-6 gene transcription; therefore, other factors and/or regulatory mechanisms presumably modulate the levels of IL-6 mRNA production. Upon analysis of various deletion and point-mutated variants of the human IL-6 gene promoter coupled to a reporter gene, we screened for possible cooperating transcription factors. Even the smallest deletion variant, containing almost exclusively a NF-kappaB-responsive sequence preceding the IL-6 minimal promoter, as well as a recombinant construction containing multiple kappaB-motifs, could still be stimulated with TNF. We observed that the p38 mitogen-activated protein kinase (MAPK) inhibitor SB203580 was able to repress TNF-stimulated expression of the IL-6 gene, as well as of a kappaB-dependent reporter gene construct, without affecting the levels of NF-kappaB binding to DNA. Furthermore, we clearly show that, using a nuclear Gal4 "one-hybrid" system, the MAPK inhibitors SB203580 and PD0980589 have a direct repressive effect on the transactivation potential of the p65 kappaB subunit. Therefore, we conclude that, in addition to cytoplasmic activation and DNA binding of NF-kappaB, the p38 and extracellular signal-regulated kinase MAPK pathways act as necessary cooperative mechanisms to regulate TNF-induced IL-6 gene expression by modulating the transactivation machinery.
Collapse
Affiliation(s)
- W Vanden Berghe
- Laboratory of Molecular Biology, Flanders Interuniversity Institute for Biotechnology and University of Gent, B-9000 Gent, Belgium
| | | | | | | | | | | | | |
Collapse
|
128
|
De Bosscher K, Schmitz ML, Vanden Berghe W, Plaisance S, Fiers W, Haegeman G. Glucocorticoid-mediated repression of nuclear factor-kappaB-dependent transcription involves direct interference with transactivation. Proc Natl Acad Sci U S A 1997; 94:13504-9. [PMID: 9391055 PMCID: PMC28335 DOI: 10.1073/pnas.94.25.13504] [Citation(s) in RCA: 296] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Glucocorticoids exert multiple anti-inflammatory activities, one of which is the inhibition of transcription dependent on the nuclear factor (NF)-kappaB. It has been suggested that the effect of dexamethasone (DEX), a glucocorticoid analog, is attributed to an increased production of the inhibitory IkappaB molecule, which in turn would bind and remove activated, DNA-bound NF-kappaB complexes in the cell nucleus. Upon investigating DEX-mediated repression of interleukin-6 expression induced by tumor necrosis factor, DEX treatment was found to act directly on NF-kappaB-dependent transcription, without changing the expression level of IkappaB. Neither the mRNA of IkappaB nor the protein was significantly elevated by a combined treatment with tumor necrosis factor and DEX of murine endothelial or fibroblast cells. The DNA-binding activity of induced NF-kappaB also remained unchanged after stimulation of cells with DEX. Evidence for a direct nuclear mechanism of action was obtained by analysis of cell lines stably expressing a fusion protein between the DNA-binding domain of the yeast Gal4 protein and the transactivating p65 subunit of NF-kappaB. Expression of a Gal4-dependent luciferase reporter gene activated by this nuclear fusion protein was also strongly repressed after addition of DEX. Because the DNA-binding activity of the Gal4 fusion protein was not affected by DEX, it can be concluded that the reduction of gene activation was caused by interference of the activated glucocorticoid receptor with the transactivation potential of the NF-kappaB p65 subunit.
Collapse
Affiliation(s)
- K De Bosscher
- Laboratory of Molecular Biology, Flanders Interuniversity Institute for Biotechnology and University of Ghent, K. L. Ledeganckstraat 35, B-9000 Ghent, Belgium
| | | | | | | | | | | |
Collapse
|
129
|
Vandevoorde V, Haegeman G, Fiers W. Induced expression of trimerized intracellular domains of the human tumor necrosis factor (TNF) p55 receptor elicits TNF effects. J Biophys Biochem Cytol 1997; 137:1627-38. [PMID: 9199176 PMCID: PMC2137820 DOI: 10.1083/jcb.137.7.1627] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
The various biological activities of tumor necrosis factor (TNF) are mediated by two receptors, one of 55 kD (TNF-R55) and one of 75 kD (TNF-R75). Although the phenotypic and molecular responses elicited by TNF in different cell types are fairly well characterized, the signaling pathways leading to them are so far only partly understood. To further unravel these processes, we focused on TNF-R55, which is responsible for mediating most of the known TNF effects. Since several studies have demonstrated the importance of receptor clustering and consequently of close association of the intracellular domains for signaling, we addressed the question of whether clustering of the intracellular domains of TNF-R55 (TNF-R55i) needs to occur in structural association with the inner side of the cell membrane, where many signaling mediators are known to reside. Therefore, we investigated whether induced intracellular clustering of only TNF-R55i would be sufficient to initiate and generate a full TNF response, without the need for a full-length receptor molecule or a transmembrane region. Our results provide clear evidence that inducible forced trimerization of either TNF-R55i or only the death domain elicits an efficient TNF response, comprising activation of the nuclear factor kappaB, induction of interleukin-6, and cell killing.
Collapse
Affiliation(s)
- V Vandevoorde
- Laboratory of Molecular Biology, Flanders Interuniversity Institute for Biotechnology and University of Ghent, B-9000 Ghent, Belgium
| | | | | |
Collapse
|