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Maes M, Plaimas K, Suratanee A, Noto C, Kanchanatawan B. First Episode Psychosis and Schizophrenia Are Systemic Neuro-Immune Disorders Triggered by a Biotic Stimulus in Individuals with Reduced Immune Regulation and Neuroprotection. Cells 2021; 10:cells10112929. [PMID: 34831151 PMCID: PMC8616258 DOI: 10.3390/cells10112929] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2021] [Revised: 10/20/2021] [Accepted: 10/24/2021] [Indexed: 12/30/2022] Open
Abstract
There is evidence that schizophrenia is characterized by activation of the immune-inflammatory response (IRS) and compensatory immune-regulatory systems (CIRS) and lowered neuroprotection. Studies performed on antipsychotic-naïve first episode psychosis (AN-FEP) and schizophrenia (FES) patients are important as they may disclose the pathogenesis of FES. However, the protein–protein interaction (PPI) network of FEP/FES is not established. The aim of the current study was to delineate a) the characteristics of the PPI network of AN-FEP and its transition to FES; and b) the biological functions, pathways, and molecular patterns, which are over-represented in FEP/FES. Toward this end, we used PPI network, enrichment, and annotation analyses. FEP and FEP/FES are strongly associated with a response to a bacterium, alterations in Toll-Like Receptor-4 and nuclear factor-κB signaling, and the Janus kinases/signal transducer and activator of the transcription proteins pathway. Specific molecular complexes of the peripheral immune response are associated with microglial activation, neuroinflammation, and gliogenesis. FEP/FES is accompanied by lowered protection against inflammation, in part attributable to dysfunctional miRNA maturation, deficits in neurotrophin and Wnt/catenin signaling, and adherens junction organization. Multiple interactions between reduced brain derived neurotrophic factor, E-cadherin, and β-catenin and disrupted schizophrenia-1 (DISC1) expression increase the vulnerability to the neurotoxic effects of immune molecules, including cytokines and complement factors. In summary: FEP and FES are systemic neuro-immune disorders that are probably triggered by a bacterial stimulus which induces neuro-immune toxicity cascades that are overexpressed in people with reduced anti-inflammatory and miRNA protections, cell–cell junction organization, and neurotrophin and Wnt/catenin signaling.
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Affiliation(s)
- Michael Maes
- Department of Psychiatry, Faculty of Medicine, Chulalongkorn University, Bangkok 10330, Thailand;
- Department of Psychiatry, Medical University of Plovdiv, 4000 Plovdiv, Bulgaria
- IMPACT Strategic Research Center, Deakin University, Geelong 3220, Australia
- Correspondence:
| | - Kitiporn Plaimas
- Advanced Virtual and Intelligent Computing (AVIC) Center, Department of Mathematics and Computer Science, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand;
| | - Apichat Suratanee
- Department of Mathematics, Faculty of Applied Science, King Mongkut’s University of Technology North Bangkok, Bangkok 10800, Thailand;
| | - Cristiano Noto
- GAPi (Early Psychosis Group), Universidade Federal de São Paulo (UNIFESP), São Paulo 04021-001, Brazil;
- Schizophrenia Program (PROESQ), Department of Psychiatry, Universidade Federal de São Paulo (UNIFESP), São Paulo 04021-001, Brazil
| | - Buranee Kanchanatawan
- Department of Psychiatry, Faculty of Medicine, Chulalongkorn University, Bangkok 10330, Thailand;
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Shukla A, Ramirez NGP, D’Orso I. HIV-1 Proviral Transcription and Latency in the New Era. Viruses 2020; 12:v12050555. [PMID: 32443452 PMCID: PMC7291205 DOI: 10.3390/v12050555] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Revised: 05/06/2020] [Accepted: 05/12/2020] [Indexed: 12/11/2022] Open
Abstract
Three decades of extensive work in the HIV field have revealed key viral and host cell factors controlling proviral transcription. Various models of transcriptional regulation have emerged based on the collective information from in vitro assays and work in both immortalized and primary cell-based models. Here, we provide a recount of the past and current literature, highlight key regulatory aspects, and further describe potential limitations of previous studies. We particularly delve into critical steps of HIV gene expression including the role of the integration site, nucleosome positioning and epigenomics, and the transition from initiation to pausing and pause release. We also discuss open questions in the field concerning the generality of previous regulatory models to the control of HIV transcription in patients under suppressive therapy, including the role of the heterogeneous integration landscape, clonal expansion, and bottlenecks to eradicate viral persistence. Finally, we propose that building upon previous discoveries and improved or yet-to-be discovered technologies will unravel molecular mechanisms of latency establishment and reactivation in a “new era”.
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Riedlinger T, Haas J, Busch J, van de Sluis B, Kracht M, Schmitz ML. The Direct and Indirect Roles of NF-κB in Cancer: Lessons from Oncogenic Fusion Proteins and Knock-in Mice. Biomedicines 2018; 6:biomedicines6010036. [PMID: 29562713 PMCID: PMC5874693 DOI: 10.3390/biomedicines6010036] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Revised: 03/16/2018] [Accepted: 03/17/2018] [Indexed: 12/24/2022] Open
Abstract
NF-κB signaling pathways play an important role in the regulation of cellular immune and stress responses. Aberrant NF-κB activity has been implicated in almost all the steps of cancer development and many of the direct and indirect contributions of this transcription factor system for oncogenesis were revealed in the recent years. The indirect contributions affect almost all hallmarks and enabling characteristics of cancer, but NF-κB can either promote or antagonize these tumor-supportive functions, thus prohibiting global NF-κB inhibition. The direct effects are due to mutations of members of the NF-κB system itself. These mutations typically occur in upstream components that lead to the activation of NF-κB together with further oncogenesis-promoting signaling pathways. In contrast, mutations of the downstream components, such as the DNA-binding subunits, contribute to oncogenic transformation by affecting NF-κB-driven transcriptional output programs. Here, we discuss the features of recently identified oncogenic RelA fusion proteins and the characterization of pathways that are regulating the transcriptional activity of NF-κB by regulatory phosphorylations. As NF-κB’s central role in human physiology prohibits its global inhibition, these auxiliary or cell type-specific NF-κB regulating pathways are potential therapeutic targets.
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Affiliation(s)
- Tabea Riedlinger
- Institute of Biochemistry, Justus-Liebig-University, D-35392 Giessen, Germany.
| | - Jana Haas
- Institute of Biochemistry, Justus-Liebig-University, D-35392 Giessen, Germany.
| | - Julia Busch
- Institute of Biochemistry, Justus-Liebig-University, D-35392 Giessen, Germany.
| | - Bart van de Sluis
- Department of Pediatrics, Molecular Genetics Section, University of Groningen, University Medical Center Groningen, Antonius Deusinglaan 1, 9713 AV, Groningen, The Netherlands.
| | - Michael Kracht
- Rudolf-Buchheim-Institute of Pharmacology, Justus-Liebig-University, D-35392 Giessen, Germany.
| | - M Lienhard Schmitz
- Institute of Biochemistry, Justus-Liebig-University, D-35392 Giessen, Germany.
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4
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Ne E, Palstra RJ, Mahmoudi T. Transcription: Insights From the HIV-1 Promoter. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2018; 335:191-243. [DOI: 10.1016/bs.ircmb.2017.07.011] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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5
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Giles KM, Brown RAM, Ganda C, Podgorny MJ, Candy PA, Wintle LC, Richardson KL, Kalinowski FC, Stuart LM, Epis MR, Haass NK, Herlyn M, Leedman PJ. microRNA-7-5p inhibits melanoma cell proliferation and metastasis by suppressing RelA/NF-κB. Oncotarget 2017; 7:31663-80. [PMID: 27203220 PMCID: PMC5077967 DOI: 10.18632/oncotarget.9421] [Citation(s) in RCA: 62] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Accepted: 05/09/2016] [Indexed: 12/11/2022] Open
Abstract
microRNA-7-5p (miR-7-5p) is a tumor suppressor in multiple cancer types and inhibits growth and invasion by suppressing expression and activity of the epidermal growth factor receptor (EGFR) signaling pathway. While melanoma is not typically EGFR-driven, expression of miR-7-5p is reduced in metastatic tumors compared to primary melanoma. Here, we investigated the biological and clinical significance of miR-7-5p in melanoma. We found that augmenting miR-7-5p expression in vitro markedly reduced tumor cell viability, colony formation and induced cell cycle arrest. Furthermore, ectopic expression of miR-7-5p reduced migration and invasion of melanoma cells in vitro and reduced metastasis in vivo. We used cDNA microarray analysis to identify a subset of putative miR-7-5p target genes associated with melanoma and metastasis. Of these, we confirmed nuclear factor kappa B (NF-κB) subunit RelA, as a novel direct target of miR-7-5p in melanoma cells, such that miR-7-5p suppresses NF-κB activity to decrease expression of canonical NF-κB target genes, including IL-1β, IL-6 and IL-8. Importantly, the effects of miR-7-5p on melanoma cell growth, cell cycle, migration and invasion were recapitulated by RelA knockdown. Finally, analysis of gene array datasets from multiple melanoma patient cohorts revealed an association between elevated RelA expression and poor survival, further emphasizing the clinical significance of RelA and its downstream signaling effectors. Taken together, our data show that miR-7-5p is a potent inhibitor of melanoma growth and metastasis, in part through its inactivation of RelA/NF-κB signaling. Furthermore, miR-7-5p replacement therapy could have a role in the treatment of this disease.
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Affiliation(s)
- Keith M Giles
- Laboratory for Cancer Medicine, Harry Perkins Institute of Medical Research and University of Western Australia Centre for Medical Research, Nedlands, WA, Australia.,Ronald O. Perelman Department of Dermatology, New York University School of Medicine, New York, NY, United States of America
| | - Rikki A M Brown
- Laboratory for Cancer Medicine, Harry Perkins Institute of Medical Research and University of Western Australia Centre for Medical Research, Nedlands, WA, Australia
| | - Clarissa Ganda
- Laboratory for Cancer Medicine, Harry Perkins Institute of Medical Research and University of Western Australia Centre for Medical Research, Nedlands, WA, Australia
| | - Melissa J Podgorny
- Laboratory for Cancer Medicine, Harry Perkins Institute of Medical Research and University of Western Australia Centre for Medical Research, Nedlands, WA, Australia
| | - Patrick A Candy
- Laboratory for Cancer Medicine, Harry Perkins Institute of Medical Research and University of Western Australia Centre for Medical Research, Nedlands, WA, Australia
| | - Larissa C Wintle
- Laboratory for Cancer Medicine, Harry Perkins Institute of Medical Research and University of Western Australia Centre for Medical Research, Nedlands, WA, Australia
| | - Kirsty L Richardson
- Laboratory for Cancer Medicine, Harry Perkins Institute of Medical Research and University of Western Australia Centre for Medical Research, Nedlands, WA, Australia
| | - Felicity C Kalinowski
- Laboratory for Cancer Medicine, Harry Perkins Institute of Medical Research and University of Western Australia Centre for Medical Research, Nedlands, WA, Australia
| | - Lisa M Stuart
- Laboratory for Cancer Medicine, Harry Perkins Institute of Medical Research and University of Western Australia Centre for Medical Research, Nedlands, WA, Australia
| | - Michael R Epis
- Laboratory for Cancer Medicine, Harry Perkins Institute of Medical Research and University of Western Australia Centre for Medical Research, Nedlands, WA, Australia
| | - Nikolas K Haass
- The University of Queensland Diamantina Institute, Translational Research Institute, Brisbane, Queensland, Australia
| | - Meenhard Herlyn
- Molecular and Cellular Oncogenesis Program, The Wistar Institute, Philadelphia, PA, United States of America
| | - Peter J Leedman
- Laboratory for Cancer Medicine, Harry Perkins Institute of Medical Research and University of Western Australia Centre for Medical Research, Nedlands, WA, Australia.,School of Medicine and Pharmacology, The University of Western Australia, Nedlands, WA, Australia
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Kim JY, Jung HH, Ahn S, Bae S, Lee SK, Kim SW, Lee JE, Nam SJ, Ahn JS, Im YH, Park YH. The relationship between nuclear factor (NF)-κB family gene expression and prognosis in triple-negative breast cancer (TNBC) patients receiving adjuvant doxorubicin treatment. Sci Rep 2016; 6:31804. [PMID: 27545642 PMCID: PMC4992884 DOI: 10.1038/srep31804] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Accepted: 07/26/2016] [Indexed: 12/21/2022] Open
Abstract
We investigated gene expression profiles of the NF-κB pathway in patients with triple-negative breast cancer (TNBC) receiving adjuvant chemotherapy to determine the prognostic value of NF-κB pathway genes according to chemotherapeutic regimen. We used the nCounter expression assay to measure expression of 11 genes (NFKB1, NFKB2, RELA, RELB, REL, TP53, FOXC1, TBP, SP1, STAT3 and IRF1 genes) belonging to the NF-κB pathway using mRNA extracted from paraffin-embedded tumor tissues from 203 patients diagnosed with TNBC. Of the 203 patients, 116 were treated with a chemotherapeutic regimen containing doxorubicin. As revealed by the expression profiles of the 11 genes, increased expression of SP1 was associated with poor prognosis in TNBC patients treated with adjuvant doxorubicin chemotherapy (5-year distant recurrence-free survival [5Y DRFS], low vs. high expression [cut-off: median]: 92.3% vs. 71.6%, P = 0.001). In a multivariate Cox regression model, SP1 expression was a useful marker for predicting long-term prognosis in TNBC patients receiving doxorubicin treatment, and we thus suggest that SP1 expression could serve as a prognostic marker in these patients.
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Affiliation(s)
- Ji-Yeon Kim
- Division of Hematology-Oncology, Department of Medicine, Samsung Medical Center, Sungkyunkwan University Seoul 06351, Korea
| | - Hae Hyun Jung
- Department of Health Sciences and Technology, SAIHST, Sungkyunkwan University, Seoul 06351, Korea
| | - Soomin Ahn
- Innovative Cancer Medicine Institute, Samsung Medical Center, Sungkyunkwan University Seoul 06351, Korea
| | - SooYoun Bae
- Department of Surgery, Samsung Medical Center, Seoul 06351, Korea
| | - Se Kyung Lee
- Department of Surgery, Samsung Medical Center, Seoul 06351, Korea
| | - Seok Won Kim
- Department of Surgery, Samsung Medical Center, Seoul 06351, Korea
| | - Jeong Eon Lee
- Department of Surgery, Samsung Medical Center, Seoul 06351, Korea
| | - Seok Jin Nam
- Department of Surgery, Samsung Medical Center, Seoul 06351, Korea
| | - Jin Seok Ahn
- Division of Hematology-Oncology, Department of Medicine, Samsung Medical Center, Sungkyunkwan University Seoul 06351, Korea
| | - Young-Hyuck Im
- Division of Hematology-Oncology, Department of Medicine, Samsung Medical Center, Sungkyunkwan University Seoul 06351, Korea
- Biomedical Research Institute, Samsung Medical Center, Sungkyunkwan University, Seoul 06351, Korea
| | - Yeon Hee Park
- Division of Hematology-Oncology, Department of Medicine, Samsung Medical Center, Sungkyunkwan University Seoul 06351, Korea
- Department of Health Sciences and Technology, SAIHST, Sungkyunkwan University, Seoul 06351, Korea
- Biomedical Research Institute, Samsung Medical Center, Sungkyunkwan University, Seoul 06351, Korea
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Preferential binding of hot spot mutant p53 proteins to supercoiled DNA in vitro and in cells. PLoS One 2013; 8:e59567. [PMID: 23555710 PMCID: PMC3608670 DOI: 10.1371/journal.pone.0059567] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2012] [Accepted: 02/19/2013] [Indexed: 11/21/2022] Open
Abstract
Hot spot mutant p53 (mutp53) proteins exert oncogenic gain-of-function activities. Binding of mutp53 to DNA is assumed to be involved in mutp53-mediated repression or activation of several mutp53 target genes. To investigate the importance of DNA topology on mutp53-DNA recognition in vitro and in cells, we analyzed the interaction of seven hot spot mutp53 proteins with topologically different DNA substrates (supercoiled, linear and relaxed) containing and/or lacking mutp53 binding sites (mutp53BS) using a variety of electrophoresis and immunoprecipitation based techniques. All seven hot spot mutp53 proteins (R175H, G245S, R248W, R249S, R273C, R273H and R282W) were found to have retained the ability of wild-type p53 to preferentially bind circular DNA at native negative superhelix density, while linear or relaxed circular DNA was a poor substrate. The preference of mutp53 proteins for supercoiled DNA (supercoil-selective binding) was further substantiated by competition experiments with linear DNA or relaxed DNA in vitro and ex vivo. Using chromatin immunoprecipitation, the preferential binding of mutp53 to a sc mutp53BS was detected also in cells. Furthermore, we have shown by luciferase reporter assay that the DNA topology influences p53 regulation of BAX and MSP/MST1 promoters. Possible modes of mutp53 binding to topologically constrained DNA substrates and their biological consequences are discussed.
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8
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Gilmore TD, Gerondakis S. The c-Rel Transcription Factor in Development and Disease. Genes Cancer 2012; 2:695-711. [PMID: 22207895 DOI: 10.1177/1947601911421925] [Citation(s) in RCA: 100] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2011] [Accepted: 08/08/2011] [Indexed: 12/21/2022] Open
Abstract
c-Rel is a member of the nuclear factor κB (NF-κB) transcription factor family. Unlike other NF-κB proteins that are expressed in a variety of cell types, high levels of c-Rel expression are found primarily in B and T cells, with many c-Rel target genes involved in lymphoid cell growth and survival. In addition to c-Rel playing a major role in mammalian B and T cell function, the human c-rel gene (REL) is a susceptibility locus for certain autoimmune diseases such as arthritis, psoriasis, and celiac disease. The REL locus is also frequently altered (amplified, mutated, rearranged), and expression of REL is increased in a variety of B and T cell malignancies and, to a lesser extent, in other cancer types. Thus, agents that modulate REL activity may have therapeutic benefits for certain human cancers and chronic inflammatory diseases.
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Lee EK, Chae JH, Kang MS. Nuclear factor-κB2 represses Sp1-mediated transcription at the CD99 promoter. Mol Cells 2011; 32:555-60. [PMID: 22083306 PMCID: PMC3887681 DOI: 10.1007/s10059-011-0177-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2011] [Revised: 10/12/2011] [Accepted: 10/13/2011] [Indexed: 10/15/2022] Open
Abstract
Downregulation of the CD99 antigen on the surface of Hodgkin's lymphoma (HL) cells via EBV LMP1-mediated NF-κB suppression of Sp1 transcriptional activity is known to be associated with the appearance of pathogenic Reed-Sternberg cells. Here, we show that in addition, EBV LMP1 heterologous NF-κB activators such as CD30 and CD40 repress the CD99 promoter, which contains multiple Sp1-binding sites but no NF-κB binding sites. In addition, NF-κB-inducing kinase (NIK) repressed the CD99 promoter while NIK kinase mutants and JNK inhibitory protein failed to do so. Of the NF-κB subunits, NF-κB2 (p52) alone or in combination with other Rel subunits consistently inhibited the CD99, while NF-κB1 (p50) showed a marginal repressive effect. Furthermore, while transfection of LMP1 repressed the CD99 promoter in wild-type or NF-κB1 deficient MEFs, the same repression was not observed in NF-κB2 (p52)-deficient MEFs, indicating that NF-κB2 (p52) is required for LMP1-mediated repression of the CD99 promoter. Consistently, basal activity of the CD99 promoter was significantly higher in IKKα(-/-) and IKKβ(-/-) MEFs, but not in IKKΓ(-/-) MEFs compared to the wild-type control MEFs. Sp1-binding sites were directly used in the repression, because a synthetic Sp1 reporter with 10 Sp1-binding sites from the CD99 promoter was repressed by LMP1 or p52 transfection. These data indicate that LMP1-mediated NF-κB2 exhibits the major inhibitory role in the transcription at the CD99 promoter.
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Affiliation(s)
- Eun Kyung Lee
- Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 135-710, Korea
- These authors contributed equally to this study
| | - Ji Hye Chae
- Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 135-710, Korea
- These authors contributed equally to this study
| | - Myung-Soo Kang
- Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 135-710, Korea
- Channing Laboratory, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, USA
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Ristola M, Arpiainen S, Saleem MA, Mathieson PW, Welsh GI, Lehtonen S, Holthöfer H. Regulation of Neph3 gene in podocytes--key roles of transcription factors NF-kappaB and Sp1. BMC Mol Biol 2009; 10:83. [PMID: 19703278 PMCID: PMC2736951 DOI: 10.1186/1471-2199-10-83] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2008] [Accepted: 08/24/2009] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Neph3 (filtrin) is expressed in the glomerular podocytes where it localizes at the specialized cell adhesion structures of the foot processes called slit diaphragms which form the outermost layer of the glomerular filtration barrier. Neph3 protein shows homology and structural similarity to Neph1, Neph2 and nephrin, which all are crucial for maintaining the normal glomerular ultrafiltration function. The exact function of Neph3 in the kidney is not known but we have previously shown that the level of Neph3 mRNA is decreased in proteinuric diseases. This suggests that Neph3 may play a role in the pathogenesis of kidney damage, and emphasizes the need to analyze the regulatory mechanisms of Neph3 gene. In this study we investigated the transcriptional regulation of Neph3 gene by identifying transcription factors that control Neph3 expression. RESULTS We cloned and characterized approximately 5 kb fragment upstream of the Neph3 gene. Neph3 proximal promoter near the transcription start site was found to be devoid of TATA and CAAT boxes, but to contain a highly GC-rich area. Using promoter reporter gene constructs, we localized the main activating regulatory region of Neph3 gene in its proximal promoter region from -105 to -57. Within this region, putative transcription factor binding sites for NF-kappaB and Sp1 were found by computational analysis. Mutational screening indicated that NF-kappaB and Sp1 response elements are essential for the basal transcriptional activity of the Neph3 promoter. Co-transfection studies further showed that NF-kappaB and Sp1 regulate Neph3 promoter activity. In addition, overexpression of NF-kappaB increased endogenous Neph3 gene expression. Chromatin immunoprecipitation assay using cultured human podocytes demonstrated that both NF-kappaB and Sp1 interact with the Neph3 promoter. CONCLUSION Our results show that NF-kappaB and Sp1 are key regulators of Neph3 expression at the basal level in podocytes, therefore providing new insight into the molecular mechanisms that contribute to the expression of Neph3 gene.
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Affiliation(s)
- Mervi Ristola
- Department of Bacteriology and Immunology, Haartman Institute, P,O, Box 21, 00014 University of Helsinki, Finland.
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Hewetson A, Chilton BS. Progesterone-dependent deoxyribonucleic acid looping between RUSH/SMARCA3 and Egr-1 mediates repression by c-Rel. Mol Endocrinol 2008; 22:813-22. [PMID: 18174357 DOI: 10.1210/me.2007-0432] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Steroids regulate alternative splicing of RUSH/SMARCA3. The full-length, progesterone-dependent alpha-isoform and the 3'-truncated, estrogen-dependent beta-isoform have identical DNA-binding domains, nuclear localization signals, and RING fingers. Transcription of RUSH/SMARCA3 is mediated by a bipartite progesterone receptor half-site/overlapping Y-box combination (-38/-26), where progesterone activation is attenuated by nuclear factor Y binding. Regulation also involves two GC-rich sequences in the proximal promoter (-162/+90) and a RUSH/SMARCA3 site (-616/-611) in the 5'-untranslated region. Isoform-specific binding to the RUSH/SMARCA3 site is dictated by the hormonal milieu, as is the availability of factors that bind to the distal GC-rich site (-131/-126), a composite binding site for Egr-1/specific protein-1/3/Myc-associated zinc finger protein/myeloid zinc finger-1/c-Rel, and the proximal GC-rich site (-62/-53), which binds only Sp1/3. TransSignal TF-TF interaction arrays, supershift assays, and chromatin immunoprecipitation analyses confirmed strong physical interactions between RUSH/Egr-1 and RUSH/c-Rel that were visualized with fluorescent microscopy. Higher-order, long-range interactions between RUSH and Egr-1/c-Rel derivative of the anisotropic flexibility of the intervening DNA sequence were shown by Chromosome Conformation Capture assay. Glutathione S-transferase pull-downs confirmed that the RING finger is the protein-binding domain, suggesting that the RUSH isoforms have equivalent potential for protein interactions. Transient transfection assays showed that the cooperative interaction between RUSH and Egr-1 mediates repression by c-Rel. Thus, progesterone-induced transcription is fine-tuned by isoform-specific autoregulation, in which newly synthesized RUSH-1alpha binds DNA and interacts physically with liganded Egr-1 in the proximal promoter via a DNA-looping mechanism to mediate repression by c-Rel. In the absence of progesterone induction, RUSH-1beta replaces RUSH-1alpha binding, Egr-1 and c-Rel are unavailable as molecular ties, and DNA looping is disfavored.
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Affiliation(s)
- Aveline Hewetson
- Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, Texas 79430, USA
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Hrdlicková R, Nehyba J, Liss AS, Bose HR. Mechanism of telomerase activation by v-Rel and its contribution to transformation. J Virol 2007; 80:281-95. [PMID: 16352553 PMCID: PMC1317554 DOI: 10.1128/jvi.80.1.281-295.2006] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Telomerase is activated during the transformation of lymphoid cells and fibroblasts by v-Rel, the oncogenic member of the Rel/NF-kappaB family of transcription factors. v-Rel-transformed cell lines have longer telomeres than untransformed chicken lymphoid cells and have high levels of telomerase activity. v-Rel-mediated activation of telomerase is achieved by multiple mechanisms. The expression of the gene encoding the catalytic subunit of telomerase (TERT) was directly upregulated by v-Rel. Moreover, the expression of v-Rel altered the ratio of alternatively spliced and full-length TERT transcripts in favor of the full-length forms. The activation of telomerase by v-Rel in lymphocytes was also accompanied by inactivation of nuclear inhibitors. The inhibition of telomerase activity in v-Rel-transformed cell lines led to apoptosis within 24 h. The expression of v-Rel in a macrophage cell line resulted in elevated levels of reactive oxygen species (ROS), increased telomerase activity, and increased sensitivity to telomerase inhibitors. In contrast, the ectopic expression of TERT decreased the extent of apoptosis induced by ROS. The activation of telomerase by v-Rel may, therefore, partially protect the transformed cells from apoptosis induced by ROS.
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Affiliation(s)
- Radmila Hrdlicková
- Section of Molecular Genetics and Microbiology, The University of Texas at Austin, Austin, TX 78712-1095, USA
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13
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Wieland GD, Nehmann N, Müller D, Eibel H, Siebenlist U, Sühnel J, Zipfel PF, Skerka C. Early growth response proteins EGR-4 and EGR-3 interact with immune inflammatory mediators NF-κB p50 and p65. J Cell Sci 2005; 118:3203-12. [PMID: 16014385 DOI: 10.1242/jcs.02445] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Here, we characterize the basis for the T-cell-specific activity of the human zinc-finger protein early growth response factor 4 (EGR-4). A yeast two-hybrid screen showed interaction of EGR-4 with NF-κB p50. Using recombinant proteins, stable physical complex formation was confirmed for EGR-4 and EGR-3 with p50 and with p65 using glutathione-S-transferase pull-down assays and surface-plasmon-resonance and peptide-spot analyses. In vivo interaction of EGR-4 and EGR-3 with NF-κB p65 was demonstrated by immunoprecipitation experiments and fluorescence-resonance-energy transfer (FRET) analysis showing interaction in the nucleus of transfected Jurkat T cells. In transfection assays, EGR-p50 complexes were transcriptionally inactive and EGR-p65 complexes strongly activated transcription of the promoters of the human genes encoding the cytokines interleukin 2, tissue necrosis factor α and ICAM-1. The EGR-p65 complexes increased reporter-gene activity about 100-fold and thus exceeded the transcriptional activities of the p65 homodimer and the p65/p50 heterodimers. The major interaction domain for p65 was localized within the third zinc finger of EGR-4 using deletion mutants for pull-down assays and peptide-spot assays. By computer modeling, this interaction domain was localized to an α-helical region and shown to have the central amino acids surface exposed and thus accessible for interaction. In summary, in T cells, the two zinc-finger proteins EGR-4 and EGR-3 interact with the specific nuclear mediator NF-κB and control transcription of genes encoding inflammatory cytokines.
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Affiliation(s)
- Gerhard D Wieland
- Department of Infection Biology, Leibniz-Institute for Natural Products, Research and Infection Biology, Hans-Knoell-Institute, Butenbergstrasse 11a, 07745 Jena, Germany
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14
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Kalaitzidis D, Ok J, Sulak L, Starczynowski DT, Gilmore TD. Characterization of a human REL-estrogen receptor fusion protein with a reverse conditional transforming activity in chicken spleen cells. Oncogene 2004; 23:7580-7. [PMID: 15326488 DOI: 10.1038/sj.onc.1207912] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Overexpression of the human REL transcription factor can malignantly transform chicken spleen cells in vitro. In this report, we have created and characterized a cDNA encoding a chimeric protein (RELDelta424-490-ER) in which sequences of a highly transforming REL mutant (RELDelta424-490) are fused to the ligand-binding domain of the human estrogen receptor (ER). Surprisingly, RELDelta424-490-ER is constitutively nuclear in A293 cells, and RELDelta424-490-ER activates transcription in the absence, but not in the presence, of estrogen in kappaB-site reporter gene assays. Furthermore, RELDelta424-490-ER transforms chicken spleen cells in the absence of estrogen, but the addition of estrogen blocks the ability of RELDelta424-490-ER-transformed cells to form colonies in soft agar, even though estrogen induces increased nuclear translocation of RELDelta424-490-ER in these cells. ERalpha can also inhibit REL-dependent transactivation in trans in an estrogen-dependent manner, and ERalpha can interact with REL in vitro. Thus, the RELDelta424-490-ER fusion protein shows an unusual, reverse hormone regulation, in that its most prominent biological activities (transformation and transactivation) are inhibited by estrogen, probably due to an estrogen-induced interaction between the ER sequences and sequences in the Rel homology domain. Nevertheless, these results indicate that the continual activity of REL is required to sustain the transformed state of chicken spleen cells in culture, suggesting that direct and specific inhibitors of REL may have therapeutic efficacy in certain human lymphoid cancers.
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15
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Safe S, Kim K. Nuclear receptor-mediated transactivation through interaction with Sp proteins. PROGRESS IN NUCLEIC ACID RESEARCH AND MOLECULAR BIOLOGY 2004; 77:1-36. [PMID: 15196889 DOI: 10.1016/s0079-6603(04)77001-4] [Citation(s) in RCA: 112] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Stephen Safe
- Department of Veterinary Physiology and Pharmacology, Texas A&M University, College Station, TX 77843-4466, USA
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16
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Milanini-Mongiat J, Pouysségur J, Pagès G. Identification of two Sp1 phosphorylation sites for p42/p44 mitogen-activated protein kinases: their implication in vascular endothelial growth factor gene transcription. J Biol Chem 2002; 277:20631-9. [PMID: 11904305 DOI: 10.1074/jbc.m201753200] [Citation(s) in RCA: 244] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Sp1 regulates activation of many genes implicated in tumor growth and cell cycle progression. We have previously demonstrated its implication in the up-regulation of vascular endothelial growth factor (VEGF) gene transcription following growth factor stimulation of quiescent cells, a situation where p42/p44 mitogen-activate protein kinase (MAPK) activity is dramatically increased. Here we show that p42/p44 MAPK directly phosphorylates Sp1 on threonines 453 and 739 both in vitro and in vivo. Mutation of these sites to alanines decreases by half the MAPK-dependent transcriptional activity of Sp1, in the context of the VEGF promoter, in SL2 Drosophila cells devoid of the endogenous Sp1 protein. Moreover, inducible overexpression of the (T453A,T739A) Sp1 double mutant compromises MAPK-driven VEGF mRNA transcription in fibroblasts. These results highlight Sp1 as a key molecular link between elevated activation of the Ras >> p42/p44MAPK signaling pathway and increased VEGF expression, two major steps deregulated in tumor cells.
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Affiliation(s)
- Julie Milanini-Mongiat
- Institute of Signalling, Developmental Biology and Cancer Research, Centre Antoine Lacassagne, 33 avenue de Valombrose, 06189 Nice cedex 2, France
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17
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Safe S. Transcriptional activation of genes by 17 beta-estradiol through estrogen receptor-Sp1 interactions. VITAMINS AND HORMONES 2001; 62:231-52. [PMID: 11345900 DOI: 10.1016/s0083-6729(01)62006-5] [Citation(s) in RCA: 306] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Estrogen receptor-alpha (ER alpha) is a ligand-activated transcription factor and a member of the nuclear receptor superfamily. The classic mechanism of ER alpha action is associated with estrogen-induced formation of a nuclear ER alpha homodimer, binding to 5'-regulatory estrogen response elements (EREs) in target gene promoters, interaction with other nuclear proteins, and general transcription factors to activate gene expression. ER alpha also interacts with Sp1 protein to transactivate genes through binding Sp1(N)xERE or Sp1(N)xERE half-site (1/2) motifs where both ER alpha and Sp1 bind DNA elements. Activation through Sp1(N)xERE1/2 requires interactions of both proteins with their cognate DNA elements as well as additional nuclear factors to form a functional ER alpha/Sp1-DNA complex. Recent studies also show that ER alpha and Sp1 physically interact and ER alpha preferentially binds to the C-terminal DNA-binding domain of Sp1 protein. Moreover, ER alpha/Sp1 can activate transcription from a consensus GC-rich Sp1 binding site in transient transfection studies in MCF-7 human breast cancer cells, and this response is also observed with ER alpha variants that do not contain the DNA-binding domain. Several genes that are induced by estrogens in MCF-7 cells are activated through one or more GC-rich sites in their regulatory regions and these include the cathepsin D, E2F1, bcl-2, c-fos, adenosine deaminase, insulinlike growth factor binding protein 4, and retinoic acid receptor alpha 1 genes. ER alpha/Sp1 and ER beta/Sp1 action is dependent on ligand structure and cell context and ER beta/Sp1 is primarily associated with decreased ligand-dependent gene expression. ER alpha/Sp1, like ER alpha/AP1, represents a pathway for hormone activation of genes in which the receptor does not bind DNA, and results of ongoing studies suggest that ER alpha/Sp1 plays an important role in transcriptional activation of multiple growth regulatory genes in breast cancer cells.
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Affiliation(s)
- S Safe
- Department of Veterinary Physiology and Pharmacology, Texas A&M University, College Station, Texas 77843-4466, USA
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18
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Gunther M, Laithier M, Brison O. A set of proteins interacting with transcription factor Sp1 identified in a two-hybrid screening. Mol Cell Biochem 2000; 210:131-42. [PMID: 10976766 DOI: 10.1023/a:1007177623283] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The two-hybrid system was used to isolate cDNA clones encoding polypeptides that interact with the N-terminal region (activation domains A, B and C) of the Sp1 transcription factor. Among the 65 collected clones, 43 contained cDNA fragments with open reading frames. They corresponded to 13 genes encoding proteins of known function and to 15 genes, the proteins of which have no known function. Six overlapping cDNA clones corresponded to the Hsc70 protein. Host cell factor (HCF-1) and the KIAA0461 gene (encoding a putative Zn-finger protein of unknown function) were both identified through the isolation of three overlapping cDNA clones. Two cDNA fragments encoding the same region of the SREBP-2 transcription factor were independently selected and two overlapping cDNA clones corresponded to the splicing factor SF3A120. Two different cDNA clones encoded the N- and C-terminal region of the Oct-1 transcription factor. Transcription factors Elf-1 and TIEG, as well as HSph2, the putative human homologue of a murine polyhomeotic gene, were each represented by a single clone. Noticeably, for the four identified transcription factors, the DNA-binding domain was excluded from the selected polypeptides. In vitro binding of the selected polypeptides to the Sp1 protein was demonstrated for the four transcription factors and for the SF3A120, Hsc70, HCF-1, HSph2 and pKIAA0461(245) proteins. Four other cDNA clones encoding polypeptides of unknown function were tested in the in vitro binding assay. All four polypeptides were found to interact with Sp1 in this assay.
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Affiliation(s)
- M Gunther
- Laboratoire de Génétique Oncologique, UMR 1599 CNRS, Institut Gustave Roussy, France
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19
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Epinat JC, Kazandjian D, Harkness DD, Petros S, Dave J, White DW, Gilmore TD. Mutant envelope residues confer a transactivation function onto N-terminal sequences of the v-Rel oncoprotein. Oncogene 2000; 19:599-607. [PMID: 10698504 DOI: 10.1038/sj.onc.1203376] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The retroviral oncoprotein v-Rel is a member of the Rel/ NF-kappaB family of transcription factors. v-Rel has multiple changes as compared to the proto-oncoprotein c-Rel, and these changes render v-Rel highly oncogenic in avian lymphoid cells. Previous results have shown that three mutant residues in the eleven helper virus-derived Envelope (Env) amino acids (aa) at the N-terminus of v-Rel are required for its full oncogenicity. In this report, we show that these mutant Env aa also enable sequences in the N-terminal half of v-Rel to activate transcription in yeast and chicken cells, under conditions where the analogous sequences from c-Rel either do not or only weakly activate transcription. Removal of the Env aa from v-Rel or site-directed mutations that revert the three mutant residues to the residues present in the Rev-A helper virus Env protein abolish this transactivation ability of v-Rel. Addition of mutant Env aa onto c-Rel is not sufficient to fully restore the transactivation function; other sequences in the N-terminal half of v-Rel are needed for full transactivating ability. A C terminally-truncated form of NF-kappaB p100 (p85), produced in HUT-78 human leukemic cells, also activates transcription in yeast, under conditions where the normal p52 and p100 proteins do not. Furthermore, transcriptional activation by p85 in yeast is likely to occur through N-terminal sequences. Taken together, these results are consistent with a model in which transactivation by N-terminal Rel Homology (RH) domain sequences in oncogenic Rel family proteins is influenced by sequences outside the RH domain.
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Affiliation(s)
- J C Epinat
- Department of Biology, Boston University, Massachusetts 02215-2406, USA
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20
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Lee RJ, Albanese C, Fu M, D'Amico M, Lin B, Watanabe G, Haines GK, Siegel PM, Hung MC, Yarden Y, Horowitz JM, Muller WJ, Pestell RG. Cyclin D1 is required for transformation by activated Neu and is induced through an E2F-dependent signaling pathway. Mol Cell Biol 2000; 20:672-83. [PMID: 10611246 PMCID: PMC85165 DOI: 10.1128/mcb.20.2.672-683.2000] [Citation(s) in RCA: 267] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The neu (c-erbB-2) proto-oncogene encodes a tyrosine kinase receptor that is overexpressed in 20 to 30% of human breast tumors. Herein, cyclin D1 protein levels were increased in mammary tumors induced by overexpression of wild-type Neu or activating mutants of Neu in transgenic mice and in MCF7 cells overexpressing transforming Neu. Analyses of 12 Neu mutants in MCF7 cells indicated important roles for specific C-terminal autophosphorylation sites and the extracellular domain in cyclin D1 promoter activation. Induction of cyclin D1 by NeuT involved Ras, Rac, Rho, extracellular signal-regulated kinase, c-Jun N-terminal kinase, and p38, but not phosphatidylinositol 3-kinase. NeuT induction of the cyclin D1 promoter required the E2F and Sp1 DNA binding sites and was inhibited by dominant negative E2F-1 or DP-1. Neu-induced transformation was inhibited by a cyclin D1 antisense or dominant negative E2F-1 construct in Rat-1 cells. Growth of NeuT-transformed mammary adenocarcinoma cells in nude mice was blocked by the cyclin D1 antisense construct. These results demonstrate that E2F-1 mediates a Neu-signaling cascade to cyclin D1 and identify cyclin D1 as a critical downstream target of neu-induced transformation.
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MESH Headings
- Animals
- Binding Sites
- Carrier Proteins
- Cell Cycle Proteins
- Cell Transformation, Neoplastic/pathology
- Cyclin D1/antagonists & inhibitors
- Cyclin D1/genetics
- Cyclin D1/metabolism
- DNA-Binding Proteins/metabolism
- E2F Transcription Factors
- E2F1 Transcription Factor
- Humans
- JNK Mitogen-Activated Protein Kinases
- MAP Kinase Signaling System
- Mammary Glands, Animal/metabolism
- Mammary Glands, Animal/pathology
- Mice
- Mice, Nude
- Mice, Transgenic
- Mitogen-Activated Protein Kinases/antagonists & inhibitors
- Mitogen-Activated Protein Kinases/metabolism
- Monomeric GTP-Binding Proteins/genetics
- Monomeric GTP-Binding Proteins/metabolism
- Mutation/genetics
- Promoter Regions, Genetic/genetics
- Proto-Oncogene Mas
- RNA, Antisense/genetics
- RNA, Antisense/physiology
- Receptor, ErbB-2/antagonists & inhibitors
- Receptor, ErbB-2/genetics
- Receptor, ErbB-2/metabolism
- Retinoblastoma-Binding Protein 1
- Sp1 Transcription Factor/metabolism
- Sp3 Transcription Factor
- Transcription Factor DP1
- Transcription Factors/metabolism
- Transcriptional Activation
- Tumor Cells, Cultured
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Affiliation(s)
- R J Lee
- Department of Developmental Biology, The Albert Einstein Cancer Center, Albert Einstein College of Medicine, Bronx, New York 10461, USA
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21
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Abstract
The avian Rev-T retrovirus encodes the v-Rel oncoprotein, which is a member of the Rel/NF-kappaB transcription factor family. v-Rel induces a rapidly fatal lymphoma/leukemia in young birds, and v-Rel can transform and immortalize a variety of avian cell types in vitro. Although Rel/NF-kappaB transcription factors have been associated with oncogenesis in mammals, v-Rel is the only member of this family that is frankly oncogenic in animal model systems. The potent oncogenicity of v-Rel is the consequence of a number of mutations that have altered its activity and regulation: for example, certain mutations decrease its ability to be regulated by IkappaBalpha, change its DNA-binding site specificity, and endow it with new transactivation properties. The study of v-Rel will continue to increase our knowledge of how cellular Rel proteins contribute to oncogenesis by affecting cell growth, altering cell-cycle regulation, and blocking apoptosis. This review will discuss biological and molecular activities of v-Rel, with particular attention to how these activities relate to structure - function aspects of the Rel/NF-kappaB transcription factors.
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Affiliation(s)
- T D Gilmore
- Biology Department, Boston University, 5 Cummington Street, Boston, Massachusetts, MA 02215-2406, USA
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22
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Rippe RA, Schrum LW, Stefanovic B, Solís-Herruzo JA, Brenner DA. NF-kappaB inhibits expression of the alpha1(I) collagen gene. DNA Cell Biol 1999; 18:751-61. [PMID: 10541434 DOI: 10.1089/104454999314890] [Citation(s) in RCA: 115] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Fibrosis results from an increase in the synthesis and deposition of type I collagen. Fibrosis is frequently associated with inflammation, which is accompanied by increased levels of tumor necrosis factor-alpha (TNFalpha) and activation of the transcription factor NF-kappaB. However, several agents known to activate NF-kappaB, such as phorbol 12-myristate 13-acetate (PMA) and TNFalpha, result in decreased expression of type I collagen. Therefore, we directly examined the effects of NF-kappaB on alpha1(I) collagen gene expression in two collagen-producing cells, NIH 3T3 fibroblasts and hepatic stellate cells (HSCs). Transient transfections of NIH 3T3 cells or HSCs using NF-kappaB p50, p65, and c-Rel expression plasmids with collagen reporter gene plasmids demonstrated a strong inhibitory effect on transcription of the collagen gene promoter. Dose-response curves showed that p65 was a stronger inhibitor of collagen gene expression than was NF-kappaB p50 or c-Rel (maximum inhibition 90%). Transient transfections with reporter gene plasmids containing one or two Spl binding sites demonstrated similar inhibitory effects of NF-kappaB p65 on the activity of these reporter genes, suggesting that the inhibitory effects of NF-kappaB p65 are mediated through the critical Spl binding sites in the alpha1(I) collagen gene promoter. Cotransfection experiments using either a super-repressor I[ke]B or Spl partially blocked the inhibitory effects of p65 on collagen reporter gene activity. Coimmunoprecipitation experiments demonstrated that NF-kappaB and Spl do interact in vivo. Nuclear run-on assays showed that NF-kappaB p65 inhibited transcription of the endogenous alpha1(I) collagen gene. Together, these results demonstrate that NF-kappaB decreases transcription of the alpha1(I) collagen gene.
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Affiliation(s)
- R A Rippe
- Department of Medicine, The University of North Carolina, Chapel Hill 27955-7038, USA.
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23
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Pena P, Reutens AT, Albanese C, D'Amico M, Watanabe G, Donner A, Shu IW, Williams T, Pestell RG. Activator protein-2 mediates transcriptional activation of the CYP11A1 gene by interaction with Sp1 rather than binding to DNA. Mol Endocrinol 1999; 13:1402-16. [PMID: 10446912 DOI: 10.1210/mend.13.8.0335] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The ovine P45 side chain cleavage (CYP11A1) enzyme gene, which catalyzes the initial enzymatic step in steroid hormone biosynthesis is transcriptionally regulated in cultured steroidogenic human trophoblastic JEG-3 cells. The ovine CYP11A1 promoter contains two GC-rich footprinted regions referred to as ovine footprints 5 (OF5) and OF3, which are well conserved among the CYP11A1 promoters of different species. These GC-rich sequences resemble activator protein-2 (AP-2)/Sp1 binding sites and were previously implicated in basal and cAMP-regulated activity of the bovine and ovine CYP11A1 promoters. In the current studies, AP-2 induced the ovine CYP11A1 promoter 4.5-fold in JEG-3 cells with full induction requiring the previously defined cAMP-responsive elements. Point mutation of OF3 abolished induction by AP-2, and OF3 was sufficient for induction by AP-2 when linked to a heterologous promoter. AP-2 induction of the CYP11A1 promoter required the basic region (N165-N278) and the carboxy terminus of AP-2 (N413-N437). In the course of investigating the mechanisms by which OF5 and OF3 regulated CYP11A1 transcription, we found that OF5 and OF3 bound Sp1 and Sp3 in JEG-3 cells. AP-2 did not bind OF5 or OF3 directly but rather formed a multiprotein complex with Sp1 in JEG-3 cells. AP-2 associated directly with Sp1 in vitro requiring the AP-2 basic region and the Sp1 carboxy terminus. AP-2 induced Sp1/Sp3 activity independently of AP-2 binding to DNA using a GAL4 paradigm. The Sp1 and Sp3 transactivation domains were linked to the DNA-binding domain of GAL4, and their activity was assessed using a luciferase reporter gene containing only the GAL4 DNA-binding sites linked to the minimal TATA site. AP-2 induced Sp1/ Sp3-GAL4 activity 3- to 4-fold, requiring both the amino and extreme carboxy terminus of AP-2. We conclude that AP-2 can bind to and stimulate Sp1 activity and induces the ovine CYP11A1 promoter through conserved Sp1/Sp3-binding sites in JEG-3 cells. The induction of Sp1 activity by AP-2 may contribute to the induction of other genes that bind Sp1.
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Affiliation(s)
- P Pena
- The Albert Einstein Cancer Center, Department of Medicine, Albert Einstein College of Medicine, Bronx, New York 10461, USA
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24
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Rekhtman N, Radparvar F, Evans T, Skoultchi AI. Direct interaction of hematopoietic transcription factors PU.1 and GATA-1: functional antagonism in erythroid cells. Genes Dev 1999; 13:1398-411. [PMID: 10364157 PMCID: PMC316770 DOI: 10.1101/gad.13.11.1398] [Citation(s) in RCA: 387] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/1999] [Accepted: 04/19/1999] [Indexed: 11/24/2022]
Abstract
Malignant transformation usually inhibits terminal cell differentiation but the precise mechanisms involved are not understood. PU.1 is a hematopoietic-specific Ets family transcription factor that is required for development of some lymphoid and myeloid lineages. PU.1 can also act as an oncoprotein as activation of its expression in erythroid precursors by proviral insertion or transgenesis causes erythroleukemias in mice. Restoration of terminal differentiation in the mouse erythroleukemia (MEL) cells requires a decline in the level of PU.1, indicating that PU.1 can block erythroid differentiation. Here we investigate the mechanism by which PU.1 interferes with erythroid differentiation. We find that PU.1 interacts directly with GATA-1, a zinc finger transcription factor required for erythroid differentiation. Interaction between PU.1 and GATA-1 requires intact DNA-binding domains in both proteins. PU.1 represses GATA-1-mediated transcriptional activation. Both the DNA binding and transactivation domains of PU.1 are required for repression and both domains are also needed to block terminal differentiation in MEL cells. We also show that ectopic expression of PU.1 in Xenopus embryos is sufficient to block erythropoiesis during normal development. Furthermore, introduction of exogenous GATA-1 in both MEL cells and Xenopus embryos and explants relieves the block to erythroid differentiation imposed by PU.1. Our results indicate that the stoichiometry of directly interacting but opposing transcription factors may be a crucial determinant governing processes of normal differentiation and malignant transformation.
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Affiliation(s)
- N Rekhtman
- Department of Cell Biology, Albert Einstein College of Medicine, Bronx, New York 10461, USA
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25
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Chun RF, Semmes OJ, Neuveut C, Jeang KT. Modulation of Sp1 phosphorylation by human immunodeficiency virus type 1 Tat. J Virol 1998; 72:2615-29. [PMID: 9525578 PMCID: PMC109697 DOI: 10.1128/jvi.72.4.2615-2629.1998] [Citation(s) in RCA: 127] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
We previously reported (K. T. Jeang, R. Chun, N. H. Lin, A. Gatignol, C. G. Glabe, and H. Fan, J. Virol. 67: 6224-6233, 1993) that human immunodeficiency virus type 1 (HIV-1) Tat and Sp1 form a protein-protein complex. Here, we have characterized the physical interaction and a functional consequence of Tat-Sp1 contact. Using in vitro protein chromatography, we mapped the region in Tat that contacts Sp1 to amino acids 30 to 55. We found that in cell-free reactions, Tat augmented double-stranded DNA-dependent protein kinase (DNA-PK)-mediated Sp1 phosphorylation in a contact-dependent manner. Tat mutants that do not bind Sp1 failed to influence phosphorylation of the latter. In complementary experiments, we also found that Tat forms protein-protein contacts with DNA-PK. We confirmed that in HeLa and Jurkat cells, Tat expression indeed increased the intracellular amount of phosphorylated Sp1 in a manner consistent with the results of cell-free assays. Furthermore, using two phosphatase inhibitors and a kinase inhibitor, we demonstrated a modulation of reporter gene expression as a consequence of changes in Sp1 phosphorylation. Taken together, these findings suggest that activity at the HIV-1 promoter is influenced by phosphorylation of Sp1 which is affected by Tat and DNA-PK.
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Affiliation(s)
- R F Chun
- Molecular Virology Section, Laboratory of Molecular Microbiology, National Institutes of Allergy and Infectious Diseases, Bethesda, Maryland 20892-0460, USA
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26
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Sieweke MH, Tekotte H, Jarosch U, Graf T. Cooperative interaction of ets-1 with USF-1 required for HIV-1 enhancer activity in T cells. EMBO J 1998; 17:1728-39. [PMID: 9501094 PMCID: PMC1170520 DOI: 10.1093/emboj/17.6.1728] [Citation(s) in RCA: 107] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The distal enhancer region of the human immunodeficiency virus 1 (HIV-1) long terminal repeat (LTR) is known to be essential for HIV replication and to contain immediately adjacent E-box and Ets binding sites. Based on a yeast one-hybrid screen we have identified the E-box binding protein USF-1 as a direct interaction partner of Ets-1 and found that the complex acts on this enhancer element. The binding surfaces of USF-1 and Ets-1 map to their DNA-binding domains and although these domains are highly conserved, the interaction is very selective within the respective protein family. USF-1 and Ets-1 synergize in specific DNA binding as well as in the transactivation of reporter constructs containing the enhancer element, and mutations of the individual binding sites dramatically reduce reporter activity in T cells. In addition, a dominant negative Ets-1 mutant inhibits both USF-1-mediated transactivation and the activity of the HIV-1 LTR in T cells. The inhibition is independent of Ets DNA-binding sites but requires the Ets binding surface on USF-1, highlighting the importance of the direct protein-protein interaction. Together these results indicate that the interaction between Ets-1 and USF-1 is required for full transcriptional activity of the HIV-1 LTR in T cells.
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Affiliation(s)
- M H Sieweke
- EMBL, Meyerhofstrasse 1, 69117 Heidelberg, Germany
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27
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Hirano F, Tanaka H, Hirano Y, Hiramoto M, Handa H, Makino I, Scheidereit C. Functional interference of Sp1 and NF-kappaB through the same DNA binding site. Mol Cell Biol 1998; 18:1266-74. [PMID: 9488441 PMCID: PMC108839 DOI: 10.1128/mcb.18.3.1266] [Citation(s) in RCA: 132] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Gene activation by NF-kappaB/Rel transcription factors is modulated by synergistic or antagonistic interactions with other promoter-bound transcription factors. For example, Sp1 sites are often found in NF-kappaB-regulated genes, and Sp1 can activate certain promoters in synergism with NF-kappaB through nonoverlapping binding sites. Here we report that Sp1 acts directly through a subset of NF-kappaB binding sites. The DNA binding affinity of Sp1 to these NF-kappaB sites, as determined by their relative dissociation constants and their relative efficiencies as competitor DNAs or as binding site probes, is in the order of that for a consensus GC box Sp1 site. In contrast, NF-kappaB does not bind to a GC box Sp1 site. Sp1 can activate transcription through immunoglobulin kappa-chain enhancer or P-selectin promoter NF-kappaB sites. p50 homodimers replace Sp1 from the P-selectin promoter by binding site competition and thereby either inhibit basal Sp1-driven expression or, in concert with Bcl-3, stimulate expression. The interaction of Sp1 with NF-kappaB sites thus provides a means to keep an elevated basal expression of NF-kappaB-dependent genes in the absence of activated nuclear NF-kappaB/Rel.
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Affiliation(s)
- F Hirano
- Max Delbrück Center for Molecular Medicine MDC, Berlin, Germany
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28
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Chen YQ, Ghosh S, Ghosh G. A novel DNA recognition mode by the NF-kappa B p65 homodimer. NATURE STRUCTURAL BIOLOGY 1998; 5:67-73. [PMID: 9437432 DOI: 10.1038/nsb0198-67] [Citation(s) in RCA: 196] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The crystal structure of the NF-kappa B p65 (RelA) homodimer in complex with a DNA target has been determined to 2.4 A resolution. The two p65 subunits are not symmetrically disposed on the DNA target. The homodimer should optimally bind to a pseudo-palindromic nine base pair target with each subunit recognizing a 5'GGAA-3' half site separated by a central A-T base pair. However, one of the subunits (subunit B) encounters a half site of 5'-GAAA-3'. The single base-pair change from G-C to A-T results in highly unfavorable interactions between this half site and the base contacting protein residues in subunit B, which leads to an 18 degrees rotation of the N-terminal terminal domain from its normal conformation. Remarkably, subunit B retains all the interactions with the sugar phosphate backbone of the DNA target. This mode of interaction allows the NF-kappa B p65 homodimer to recognize DNA targets containing only one cognate half site. Differences in the sequence of the other half site provide variations in conformation and affinity of the complex.
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Affiliation(s)
- Y Q Chen
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla 92093-0359, USA
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Nourbakhsh M, Hauser H. The transcriptional silencer protein NRF: a repressor of NF-kappa B enhancers. Immunobiology 1997; 198:65-72. [PMID: 9442378 DOI: 10.1016/s0171-2985(97)80027-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
NF-kappa B/rel proteins are present in most cell types. In concert with other transcriptional factors they regulate a variety of genes which contribute to a wide spectrum of physiological activities like inflammation and apoptosis. An excellent example of this combinatorial regulation takes place in the IFN-beta promoter. In this promoter the fundamental regulatory elements are assembled within less than 100 base pairs including a NF-kappa B/rel enhancer and a negative regulatory element, called NRE. NRE is a member of a new class of transcriptional repressor sequences with a silencing capacity targeted to the NF-kappa B/rel enhancer. NRF is a novel transcriptional factor that binds to NRE. NRF belongs to a major class of transcriptional repressors that interact with specific promoter elements and repress transcription by separable repression domains. Such molecules have been termed active repressors, because they act by inhibitory protein-protein interaction and not simply by steric hindrance.
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Affiliation(s)
- M Nourbakhsh
- Department of Gene Regulation and Differentiation, GBF-Gesellschaft für Biotechnologische Forschung mbH, Braunschweig, Germany
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Nerve growth factor induces transcription of the p21 WAF1/CIP1 and cyclin D1 genes in PC12 cells by activating the Sp1 transcription factor. J Neurosci 1997. [PMID: 9236224 DOI: 10.1523/jneurosci.17-16-06122.1997] [Citation(s) in RCA: 123] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The PC12 pheochromocytoma cell line responds to nerve growth factor (NGF) by gradually exiting from the cell cycle and differentiating to a sympathetic neuronal phenotype. We have shown previously () that NGF induces the expression of the p21 WAF1/CIP1/Sdi1 (p21) cyclin-dependent kinase (Cdk) inhibitor protein and the G1 phase cyclin, cyclin D1. In this report, we show that induction is at the level of transcription and that the DNA elements in both promoters that are required for NGF-specific induction are clusters of binding sites for the Sp1 transcription factor. NGF also induced a synthetic promoter with repeated Sp1 sites linked to a core promoter, and a plasmid regulated by a chimeric transactivator in which the Gal4 DNA binding domain is fused to the Sp1 transactivation domain, indicating that this transactivation domain is regulated by NGF. Epidermal growth factor, which is a weak mitogen for PC12, failed to induce any of these promoter constructs. We consider a model in which the PC12 cell cycle is arrested as p21 accumulates and attains inhibitory levels relative to Cdk/cyclin complexes. Sustained activation of p21 expression is proposed to be a distinguishing feature of the activity of NGF that contributes to PC12 growth arrest during differentiation
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32
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Yan GZ, Ziff EB. Nerve growth factor induces transcription of the p21 WAF1/CIP1 and cyclin D1 genes in PC12 cells by activating the Sp1 transcription factor. J Neurosci 1997; 17:6122-32. [PMID: 9236224 PMCID: PMC6568361] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
The PC12 pheochromocytoma cell line responds to nerve growth factor (NGF) by gradually exiting from the cell cycle and differentiating to a sympathetic neuronal phenotype. We have shown previously () that NGF induces the expression of the p21 WAF1/CIP1/Sdi1 (p21) cyclin-dependent kinase (Cdk) inhibitor protein and the G1 phase cyclin, cyclin D1. In this report, we show that induction is at the level of transcription and that the DNA elements in both promoters that are required for NGF-specific induction are clusters of binding sites for the Sp1 transcription factor. NGF also induced a synthetic promoter with repeated Sp1 sites linked to a core promoter, and a plasmid regulated by a chimeric transactivator in which the Gal4 DNA binding domain is fused to the Sp1 transactivation domain, indicating that this transactivation domain is regulated by NGF. Epidermal growth factor, which is a weak mitogen for PC12, failed to induce any of these promoter constructs. We consider a model in which the PC12 cell cycle is arrested as p21 accumulates and attains inhibitory levels relative to Cdk/cyclin complexes. Sustained activation of p21 expression is proposed to be a distinguishing feature of the activity of NGF that contributes to PC12 growth arrest during differentiation
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Affiliation(s)
- G Z Yan
- Howard Hughes Medical Institute, Department of Biochemistry, Kaplan Cancer Center, New York University Medical Center, New York, New York 10016, USA
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Yurochko AD, Mayo MW, Poma EE, Baldwin AS, Huang ES. Induction of the transcription factor Sp1 during human cytomegalovirus infection mediates upregulation of the p65 and p105/p50 NF-kappaB promoters. J Virol 1997; 71:4638-48. [PMID: 9151857 PMCID: PMC191685 DOI: 10.1128/jvi.71.6.4638-4648.1997] [Citation(s) in RCA: 122] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
During human cytomegalovirus (HCMV) infection, the promoters for the classical NF-kappaB subunits (p65 and p105/p50) are transactivated. Previously, we demonstrated that the viral immediate-early (IE) proteins (IE1-72, IE2-55, and IE2-86) were involved in this upregulation. These viral factors alone, however, could not account for the entirety of the increased levels of transcription. Because one of the hallmarks of HCMV infection is the induction of cellular transcription factors, we hypothesized that one or more of these induced factors was also critical to the regulation of NF-kappaB during infection. Sp1 was one such factor that might be involved because p65 promoter activity was upregulated by Sp1 and both of the NF-kappaB subunit promoters are GC rich and contain Sp1 binding sites. Therefore, to detail the role that Sp1 plays in the regulation of NF-kappaB during infection, we initially examined Sp1 levels for changes during infection. HCMV infection resulted in increased Sp1 mRNA expression, protein levels, and DNA binding activity. Because both promoters were transactivated by Sp1, we reasoned that the upregulation of Sp1 played a role in p65 and p105/p50 promoter activity during infection. To address the specific role of Sp1 in p65 and p105/p50 promoter transactivation by HCMV, we mutated both promoters. These results demonstrated that the Sp1-specific DNA binding sites were involved in the virus-mediated transactivation. Last, to further dissect the role of HCMV in the Sp1-mediated induction of NF-kappaB, we examined the role that the viral IE genes played in Sp1 regulation. The IE gene products (IE1-72, IE2-55, and IE2-86) cooperated with Sp1 to increase promoter transactivation and physically interacted with Sp1. In addition, the IE2-86 product increased Sp1 DNA binding by possibly freeing up inactive Sp1. These data supported our hypothesis that Sp1 was involved in the upregulation of NF-kappaB during HCMV infection through the Sp1 binding sites in the p65 and p105/p50 promoters and additionally demonstrated a potential viral mechanism that might be responsible for the upregulation of Sp1 activity.
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Affiliation(s)
- A D Yurochko
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, 27599-7295, USA.
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Yang X, Herrmann CH, Rice AP. The human immunodeficiency virus Tat proteins specifically associate with TAK in vivo and require the carboxyl-terminal domain of RNA polymerase II for function. J Virol 1996; 70:4576-84. [PMID: 8676484 PMCID: PMC190394 DOI: 10.1128/jvi.70.7.4576-4584.1996] [Citation(s) in RCA: 118] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Human immunodeficiency virus types 1 and 2 encode closely related proteins, Tat-1 and Tat-2, that stimulate viral transcription. Previously, we showed that the activation domains of these proteins specifically interact in vitro with a cellular protein kinase named TAK. In vitro, TAK phosphorylates the Tat-2 but not the Tat-1 protein, a 42-kDa polypeptide of unknown identity, and the carboxyl-terminal domain (CTD) of RNA polymerase II (RNAP II). We now show that the 42-kDa substrate of TAK cochromatographs with TAK activity, suggesting that this 42-kDa polypeptide is a subunit of TAK. We also show that the Tat proteins specifically associate with TAK in vivo, since wild-type Tat-1 and Tat-2 proteins expressed in mammalian cells, but not mutant Tat proteins containing a nonfunctional activation domain, can be coimmunoprecipitated with TAK. We also mapped the in vivo phosphorylation sites of Tat-2 to the carboxyl terminus of the protein, but analysis of proteins with mutations at these sites suggests that phosphorylation is not essential for Tat-2 transactivation function. We further investigated whether the CTD of RNAP II is required for Tat function in vivo. Using plasmid constructs that express an alpha-amanitin-resistant RNAP II subunit with a truncated or full-length CTD, we found that an intact CTD is required for Tat function. These observations strengthen the proposal that the mechanism of action of Tat involves the recruitment or activation of TAK, resulting in activated transcription through phosphorylation of the CTD.
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Affiliation(s)
- X Yang
- Division of Molecular Virology, Baylor College of Medicine, Houston, Texas 77030, USA
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Viswanathan M, Yu M, Mendoza L, Yunis JJ. Cloning and transcription factor-binding sites of the human c-rel proto-oncogene promoter. Gene 1996; 170:271-6. [PMID: 8666258 DOI: 10.1016/0378-1119(95)00773-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
We report here the cloning, sequencing, functional analysis and DNase I footprinting of the human c-rel promoter region. The results revealed an 824-bp BsaAI-StuI minimal promoter region with a large number of NF-kappa B, Ap2 and Sp1-binding sites, some of them variants of known consensus sequences. This is the first promoter in the Rel/NF-kappa B/I kappa B family to be subjected to a detailed footprinting analysis for the binding of transcription activator proteins. Our finding of 14 Ap2-binding sites may indicate why the human c-rel promoter, unlike the chicken c-rel promoter, has a strong function and is highly responsive to phorbol esters. The presence of five NF-kappa B and six Sp1-binding sites in turn adds to growing evidence that, in mammals, the promoter of the Rel/NF-kappa B/I kappa B family may utilize multiple NF-kappa B- and Sp1-binding sites for their interactive regulation. Furthermore, there are putative binding sites for the PU.1 and Oct 1/2 transcription activator proteins, also present in the mouse c-rel promoter, which may help explain the preferential transcription of the c-rel gene in B- and T-lymphoid cells.
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Affiliation(s)
- M Viswanathan
- Department of Pathology, Thomas Jefferson University, Philadelphia, PA 19107-6799, USA
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White DW, Pitoc GA, Gilmore TD. Interaction of the v-Rel oncoprotein with NF-kappaB and IkappaB proteins: heterodimers of a transformation-defective v-Rel mutant and NF-2 are functional in vitro and in vivo. Mol Cell Biol 1996; 16:1169-78. [PMID: 8622661 PMCID: PMC231099 DOI: 10.1128/mcb.16.3.1169] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
The v-Rel oncoprotein of the avian Rev-T retrovirus is a member of the Rel/NF-kappa B family of transcription factors. The mechanism by which v-Rel malignantly transforms chicken spleen cells is not precisely known. To gain a better understanding of functions needed for transformation by v-Rel, we have now characterized the activities of mutant v-Rel proteins that are defective for specific protein-protein interactions. Mutant v-delta NLS, which has a deletion of the primary v-Rel nuclear localizing sequence, does not interact efficiently with I kappa B-alpha but still transforms chicken spleen cells approximately as well as wild-type v-Rel, indicating that interaction with I kappa B-alpha is not essential for the v-Rel transforming function. A second v-Rel mutant, v-SPW, has been shown to be defective for the formation of homodimers, DNA binding, and transformation. However, we now find that v-SPW can form functional DNA-binding heterodimers in vitro and in vivo with the cellular protein NF-kappa B p-52. Most strikingly, coexpression of v-SPW and p52 from a retroviral vector can induce the malignant transformation of chicken spleen cells, whereas expression of either protein alone cannot. Our results are most consistent with a model wherein Rel homodimers or heterodimers must bind DNA and alter gene expression in order to transform lymphoid cells.
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Affiliation(s)
- D W White
- Department of Biology, Boston Univeristy, Massachusetts 02215, USA
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Herrmann CH, Gold MO, Rice AP. Viral transactivators specifically target distinct cellular protein kinases that phosphorylate the RNA polymerase II C-terminal domain. Nucleic Acids Res 1996; 24:501-8. [PMID: 8602364 PMCID: PMC145661 DOI: 10.1093/nar/24.3.501] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Phosphorylation of the carboxyl-terminal domain (CTD) of the largest subunit of RNA polymerase II has been implicated as an important step in transcriptional regulation. Previously, we reported that a cellular CTD kinase, TAK, is targeted by the human immunodeficiency virus transactivator Tat. In the present study, we analyzed several other transactivators for the ability to interact with CTD kinases in vitro. The adenovirus E1A and herpes simplex virus VP16 proteins, but not other transactivators tested, were found to associate with a cellular kinase activity that hyperphosphorylates the CTD. The interaction is dependent upon a functional activation domain of E1A or VP16, suggesting that the interaction with a CTD kinase is relevant for the transactivation function of these proteins. The CTD kinase activities that interact with E1A and VP16 are related to each other but distinct from TAK. The Tat-, E1A- and VP16-associated CTD kinase activities detected in our assay also appear unrelated to MO15, the catalytic component of the CTD kinase activity of the general transcription factor TFIIH. Thus, this study has identified a novel interaction between viral transactivators and a cellular CTD kinase and suggests that at least two CTD kinases may mediate responses to viral transactivators.
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Affiliation(s)
- C H Herrmann
- Division of Molecular Virology, Baylor College of Medicine, Houston, TX 77030, USA
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Pazin MJ, Sheridan PL, Cannon K, Cao Z, Keck JG, Kadonaga JT, Jones KA. NF-kappa B-mediated chromatin reconfiguration and transcriptional activation of the HIV-1 enhancer in vitro. Genes Dev 1996; 10:37-49. [PMID: 8557193 DOI: 10.1101/gad.10.1.37] [Citation(s) in RCA: 158] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
NF-kappa B is a potent inducible transcription factor that regulates many genes in activated T cells. In this report we examined the ability of different subunits of NF-kappa B to enhance HIV-1 transcription in vitro with chromatin templates. We find that the p65 subunit of NF-kappa B is a strong transcriptional activator of nucleosome-assembled HIV-1 DNA, whereas p50 does not activate transcription, and that p65 activates transcription synergistically with Sp1 and distal HIV-1 enhancer-binding factors (LEF-1, Ets-1, and TFE-3). These effects were observed with chromatin, but not with nonchromatin templates. Furthermore, binding of either p50 or p65 with Sp1 induces rearrangement of the chromatin to a structure that resembles the one reported previously for integrated HIV-1 proviral DNA in vivo. These results suggest that p50 and Sp1 contribute to the establishment of the nucleosomal arrangement of the uninduced provirus in resting T cells, and that p65 activates transcription by recruitment of the RNA polymerase II transcriptional machinery to the chromatin-repressed basal promoter.
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Affiliation(s)
- M J Pazin
- Department of Biology, University of California, San Diego (UCSD), La Jolla 92093-0347, USA
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Ofir R, Novick I, Krup M, Cleveland JL, Ihle JN, Weinstein Y. Structural and functional analysis of the promoter of the murine V gamma 1.1 T cell receptor gene. Eur J Immunol 1995; 25:3070-8. [PMID: 7489745 DOI: 10.1002/eji.1830251113] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The expression of the germ-line gene V gamma 1.1-C gamma 4 of the T cell receptor (TcR) gamma chain depends on interleukin (IL)-3 induction in hematopoietic cells, while in T cells, the rearranged gene is expressed constitutively. To understand the mechanism that controls TcR gamma gene expression, we cloned and characterized the structure and function of the V gamma 1.1-C gamma 4 TcR promoter. IL-3-dependent cell lines and T cell lines utilized the same transcriptional start sites. In chloramphenicol acetyltransferase (CAT) assays, the minimal 70-bp promoter confers strong transcriptional activity which is 50-60% of the Moloney long terminal repeat promoter activity. The 500-bp promoter region linked to the CAT gene exhibits IL-3 dependency similar to the endogenous TcR gamma gene. The immediate 3' and 5' flanking sequences inhibit the promoter activity two- to fourfold. The promoter lacks an obvious TATA box or CAAT box sequences, but contains a GC box in the untranslated region 3' to the promoter. The GC box is the core sequence of the element which binds Sp1-like proteins. Cloning of this Sp1 binding element in front of the thymidine kinase (TK) promoter and mutations generated in this site demonstrate its function as a silencer. Ultraviolet cross-linking analysis with the Sp1 binding site from the TcR gamma promoter revealed binding of a 90-100-kDa protein in a T cell line (EL-4) and 40-50 and 90-100-kDa proteins in FDC-P1 cells. The possible function of the Sp1-like protein in silencing the minimal promoter activity is discussed.
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Affiliation(s)
- R Ofir
- Department of Microbiology and Immunology, Ben Gurion University of the Negev, Beer Sheva, Israel
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McDonald PP, Cassatella MA, Bald A, Maggi E, Romagnani S, Gruss HJ, Pizzolo G. CD30 ligation induces nuclear factor-kappa B activation in human T cell lines. Eur J Immunol 1995; 25:2870-6. [PMID: 7589085 DOI: 10.1002/eji.1830251024] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
CD30 is a recently described member of the tumor necrosis factor/nerve growth factor receptor superfamily. In this report, we show that following incubation of L540 cells (Hodgkin's disease-derived, T cell-like, CD30+ cells) with the agonistic anti-CD30 monoclonal antibodies (mAb) M44 and M67, two nuclear factor (NF)-kappa B DNA binding activities were induced in nuclear extracts, as determined in gel retardation assays. The effect of the mAb towards NF-kappa B activation was rapid, as it occurred within 20 min, and was sustained for up to 6 h. By comparison, an isotype-matched antibody had no effect on NF-kappa B activation. Moreover, in human T helper (Th) clones functionally characterized as being of the type 0, type 1 and type 2 (28%, < 1% und 93% CD30+, respectively), the extent of CD30-mediated NF-kappa B activation correlated with the proportion of CD30+ cells. In all cell lines investigated, the NF-kappa B complexes induced following CD30 engagement were shown to contain p50 NF-kappa B1, p65 RelA, and possibly other transcription factors. Collectively, our results demonstrate that nuclear translocation and activation of NF-kappa B rank among the short-term cellular responses elicited following CD30 ligation.
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Affiliation(s)
- P P McDonald
- Department of General Pathology, University of Verona, Italy
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Schatzle JD, Kralova J, Bose HR. Avian I kappa B alpha is transcriptionally induced by c-Rel and v-Rel with different kinetics. J Virol 1995; 69:5383-90. [PMID: 7636983 PMCID: PMC189381 DOI: 10.1128/jvi.69.9.5383-5390.1995] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The Rel/NF-kappa B family of transcription factors participates in the regulation of genes involved in defense responses, inflammation, healing and regeneration processes, and embryogenesis. The control of the transcriptional activation potential of the Rel/NF-kappa B proteins is mediated, in part, by their association with inhibitory proteins of the I kappa B family. This association results in the cytoplasmic retention of these factors until the cell receives a proper stimulatory signal. The I kappa B alpha gene is a target for regulation by the Rel/NF-kappa B proteins and is in fact upregulated in response to Rel/NF-kappa B activation. A naturally occurring oncogenic variant of the Rel/NF-kappa B family, v-rel, transforms avian lymphocytes, bone marrow cells, monocytes, and fibroblasts. Avian I kappa B alpha expression is upregulated in cells transformed by v-Rel. Avian I kappa B alpha is also upregulated in fibroblasts overexpressing c-Rel and oncogenic variants of c-Rel. c-Rel, a carboxy-terminally truncated variant of c-Rel, and v-Rel are all able to directly transactivate the expression of the avian I kappa B alpha gene. However, c-Rel was the most potent activator of this gene, and the induction of I kappa B alpha expression showed faster kinetics in cells overexpressing c-Rel than in those overexpressing v-Rel. The regulation of I kappa B alpha induction by the Rel proteins was shown to be dependent on a 362-bp region of the I kappa B alpha promoter that contains two potential NF-kappa B binding sites and one AP-1-like binding site. Results of electrophoretic mobility shift assays using these NF-kappa B binding sites indicate that major changes in the profile of DNA binding complexes in fibroblasts overexpressing v-Rel correlated temporally with the kinetic changes in v-Rel's ability to activate the expression of the I kappa B alpha gene.
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Affiliation(s)
- J D Schatzle
- Department of Microbiology, University of Texas at Austin 78712-1095, USA
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