101
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Oguariri RM, Brann TW, Imamichi T. Hydroxyurea and interleukin-6 synergistically reactivate HIV-1 replication in a latently infected promonocytic cell line via SP1/SP3 transcription factors. J Biol Chem 2006; 282:3594-604. [PMID: 17150965 DOI: 10.1074/jbc.m608150200] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The existence of viral latency limits the success of highly active antiretroviral therapy. With the therapeutic intention of reactivating latent virus to induce a cure, in this study we assessed the impact of cell synchronizers on HIV gene activation in latently infected U1 cells and investigated the molecular mechanisms responsible for such effect. Latently infected U1 cells were treated with 10 drugs including hydroxyurea (HU) and HIV-1 replication monitored using a p24 antigen capture assay. We found that HU was able to induce HIV-1 replication by 5-fold. HU has been used in the clinical treatment of HIV-1-infected patients in combination with didanosine; therefore, we investigated the impact of HU on HIV-1 activation in the presence of the proinflammatory cytokines, interleukin 6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha). IL-6 or TNF-alpha alone induced HIV replication by 18- and approximately 500-fold, respectively. Of interest, in the presence of HU, IL-6-mediated HIV-1 activation was enhanced by >90-fold, whereas TNF-alpha-mediated activation was inhibited by >30%. A reporter gene assay showed that HU and IL-6 synergized to activate HIV promoter activity via the Sp1 binding site. Electrophoretic mobility shift and supershift assays revealed increased binding of the Sp1 and Sp3 transcription factors to this region. Western blot analysis showed that HU and IL-6 co-stimulation resulted in increased levels of Sp1 and Sp3 proteins. In contrast, treatment with HU plus TNF-alpha down-regulated the expression of NF-kappaB. These findings suggest that Sp1/Sp3 is involved in controlling the HU/IL-6-induced reactivation of HIV-1 in latently infected cells.
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Affiliation(s)
- Raphael M Oguariri
- Laboratory of Human Retrovirology, Clinical Services Program, Science Applications International Corporation-Frederick Inc., NCI-Frederick, National Institutes of Health, Frederick, Maryland 21702, USA
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102
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Raymond AD, Hasham M, Tsygankov AY, Henderson EE. H. saimiri tyrosine-kinase interacting protein inhibits Tat function: A prototypic strategy for restricting HIV-1-induced cytopathic effects in immune cells. Virology 2006; 352:253-67. [PMID: 16780912 DOI: 10.1016/j.virol.2006.04.016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2005] [Revised: 02/09/2006] [Accepted: 04/11/2006] [Indexed: 10/24/2022]
Abstract
Herpesvirus saimiri (HVS)-transformed human T cells become permissive for X4 and R5 strains of human immunodeficiency virus type 1 (HIV-1), evidence that HVS-encoded proteins associated with T cell transformation enhance HIV-1 replication. Analyzing the contribution of transformation-associated bicistronic HVS open reading frames (ORF) to HIV-1 replication revealed expression of the second ORF saimiri transformation-associated protein type C (StpC) conferred the permissive phenotype to T cells. In contrast, expression of the first HVS ORF tyrosine-kinase interacting protein (Tip) in the absence of StpC enhanced restriction of HIV-1 replication in T cell lines and peripheral blood mononuclear cells. Understanding the mechanism whereby Tip enhanced restriction of HIV-1 replication may uncover unique pathways that could be targeted therapeutically. Here we report that Tip restricts HIV-1 replication in a monocyte-derived cell line and restricts reactivation of replication of HIV-1 in a T cell line harboring provirus. In this report, we begin to unravel the molecular underpinnings of Tip-mediated restriction. Tip mediates both lymphocyte-cell-specific kinase (Lck)-dependent and -independent effects on HIV-1 replication. We also provide evidence that Tip-mediated restriction is in part due to inhibition of Tat transactivation of the HIV-1 long terminal repeat (LTR). Expression of Tip in T cells increased activation of Stat1 and Stat3, as well as activation of protein kinase RNA-dependent (PKR/p68) and interferon-gamma production. Taken together, these results provide evidence that Tip restricts HIV-1 replication and reactivation by inhibiting HIV-1 transcription while inducing an intercellular antiviral state. We propose that genetically engineered vectors driving Tip expression could provide a prototypic strategy for restricting HIV-1 replication and reactivation in diverse cell lineages.
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Affiliation(s)
- Andrea D Raymond
- Department of Microbiology and Immunology, Temple University School of Medicine, 3400 North Broad Street, Philadelphia, PA 19140, USA
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103
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Cassol E, Alfano M, Biswas P, Poli G. Monocyte-derived macrophages and myeloid cell lines as targets of HIV-1 replication and persistence. J Leukoc Biol 2006; 80:1018-30. [PMID: 16946020 DOI: 10.1189/jlb.0306150] [Citation(s) in RCA: 116] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
HIV infection of mononuclear phagocytes (MP), mostly as tissue macrophages, is a dominant feature in the pathogenesis of HIV disease and its progression to AIDS. Although the general mechanism of infection is not dissimilar to that of CD4+ T lymphocytes occurring via interaction of the viral envelope with CD4 and a chemokine receptor (usually CCR5), other features are peculiar to MP infection. Among others, the long-term persistence of productive infection, sustained by the absence of substantial cell death, and the capacity of the virions to bud and accumulate in intracellular multivesicular bodies (MVB), has conferred to MP the role of "Trojan horses" perpetuating the chronic state of infection. Because the investigation of tissue macrophages is often very difficult for both ethical and practical reasons of accessibility, most studies of in vitro infection rely upon monocyte-derived macrophages (MDM), a methodology hampered by inter-patient variability and lack of uniformity of experimental protocols. A number of cell lines, mostly Mono Mac, THP-1, U937, HL-60, and their derivative chronically infected counterparts (such as U1 and OM-10.1 cell lines) have complemented the MDM system of infection providing useful information on the features of HIV replication in MP. This article describes and compares the most salient features of these different cellular models of MP infection by HIV.
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Affiliation(s)
- Edana Cassol
- AIDS Immunopathogenesis Unit, San Raffaele Scientific Institute, Italy
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104
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Sahu GK, Lee K, Ji J, Braciale V, Baron S, Cloyd MW. A novel in vitro system to generate and study latently HIV-infected long-lived normal CD4+ T-lymphocytes. Virology 2006; 355:127-37. [PMID: 16919704 DOI: 10.1016/j.virol.2006.07.020] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2006] [Revised: 03/13/2006] [Accepted: 07/11/2006] [Indexed: 11/30/2022]
Abstract
Studies of mechanisms of HIV-latency and its reactivation in long-lived resting CD4+ T-lymphocytes in patients have been limited due to the very low frequency of these cells ( approximately 1-10 cells per 10(6) CD4+ T-cells). To circumvent this obstacle, an in vitro culture system for post-activation long-term survival of normal CD4+ T-cells in a quiescent (non-cycling) state was developed and used to generate latently infected, long-lived quiescent CD4+ T-cells from HIV-infected, activated normal CD4+ T-lymphocytes. This yielded a frequency of approximately 5x10(4) latently infected cells per 10(6) cells in culture, which is approximately 10(3)- to 10(4)-fold higher than that available from patients. Moreover, 5-10% of long-term surviving non-cycling T-cells were found to make infectious HIV continuously at low levels, showing that HIV production from infected T-cells does not require full cellular activation. This model system should facilitate studies of long-lived, latently infected and persistently HIV-producing quiescent normal CD4+ T-lymphocytes.
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Affiliation(s)
- Gautam K Sahu
- Department of Microbiology and Immunology, The University of Texas Medical Branch, 301 University Blvd, BSB #3.132, Galveston, TX 77555, USA
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105
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Bisgrove D, Lewinski M, Bushman F, Verdin E. Molecular mechanisms of HIV-1 proviral latency. Expert Rev Anti Infect Ther 2006; 3:805-14. [PMID: 16207172 DOI: 10.1586/14787210.3.5.805] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
While great strides have been made in the treatment of HIV infection with highly active antiretroviral therapy, an actual cure remains out of grasp. One confounding factor is the persistence of a small population of infected cells containing transcriptionally silent but reactivatable HIV proviruses. Following cessation of highly active antiretroviral therapy, these latently-infected cells serve as an inoculum for re-establishing an active infection. Recent progress in our understanding of the molecular mechanisms underlying HIV proviral latency will be reviewed. Recent advances in the study of transcriptional regulation and the completion of the Human Genome Project underscore the role of chromatin and the site of viral integration on HIV transcription. Finally, experimental therapies designed to eliminate the latent population will be highlighted.
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Affiliation(s)
- Dwayne Bisgrove
- Gladstone Institute of Virology and Immunology, University of California, San Francisco, CA 94158, USA.
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106
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Klichko V, Archin N, Kaur R, Lehrman G, Margolis D. Hexamethylbisacetamide remodels the human immunodeficiency virus type 1 (HIV-1) promoter and induces Tat-independent HIV-1 expression but blunts cell activation. J Virol 2006; 80:4570-9. [PMID: 16611917 PMCID: PMC1472000 DOI: 10.1128/jvi.80.9.4570-4579.2006] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Hexamethylbisacetamide (HMBA) induces human immunodeficiency virus type 1 (HIV-1) gene expression in latently infected T-cell and monocytoid cell lines. We find that HMBA activation of viral expression is Tat independent but, like Tat, increases the efficiency of elongation of the HIV-1 promoter (long terminal repeat [LTR]) transcripts. Further, exposure to HMBA induces chromatin remodeling at nucleosome 1 (Nuc-1) near the start site of LTR transcription but does so without increasing histone acetylation or altering histone methylation near Nuc-1. Of note, despite enhanced proviral expression, HMBA suppressed HIV infection ex vivo in primary blood mononuclear cell (PBMC) cultures. Treatment with HMBA did not alter expression of the HIV coreceptors, CCR5 and CXCR4, in PBMCs but down-regulated CD4. Finally, HMBA interferes with cell proliferation and activation; it suppressed expression of Ki67 and CD25 and in PBMCs exposed to mitogen. As HMBA has been tested in oncology trials, its unusual properties make it a useful reagent for future studies of HIV promoter regulation and a novel prototype molecule for therapeutics that abort the latent proviral state of chronic HIV infection.
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MESH Headings
- Acetamides/pharmacology
- Biomarkers
- CD4 Antigens/metabolism
- CD4-Positive T-Lymphocytes/drug effects
- CD4-Positive T-Lymphocytes/immunology
- CD4-Positive T-Lymphocytes/metabolism
- Cells, Cultured
- Chromatin Assembly and Disassembly/drug effects
- Endodeoxyribonucleases/metabolism
- Gene Expression Regulation, Viral/drug effects
- Gene Expression Regulation, Viral/genetics
- Gene Products, tat/metabolism
- HIV Long Terminal Repeat/genetics
- HIV-1/drug effects
- HIV-1/genetics
- HIV-1/physiology
- Histones/genetics
- Humans
- Ki-67 Antigen/metabolism
- Promoter Regions, Genetic/genetics
- Receptors, Interleukin-2/metabolism
- Receptors, Virus/metabolism
- Transcription, Genetic/drug effects
- Transcription, Genetic/genetics
- tat Gene Products, Human Immunodeficiency Virus
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Affiliation(s)
- Vladimir Klichko
- North Texas Veterans Health Care Systems, Dallas, Texas 75216, USA
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107
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Rizzi C, Crippa MP, Jeeninga RE, Berkhout B, Blasi F, Poli G, Alfano M. Pertussis toxin B-oligomer suppresses IL-6 induced HIV-1 and chemokine expression in chronically infected U1 cells via inhibition of activator protein 1. THE JOURNAL OF IMMUNOLOGY 2006; 176:999-1006. [PMID: 16393986 DOI: 10.4049/jimmunol.176.2.999] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Pertussis toxin B-oligomer (PTX-B) inhibits HIV replication in T lymphocytes and monocyte-derived macrophages by interfering with multiple steps of the HIV life cycle. PTX-B prevents CCR5-dependent (R5) virus entry in a noncompetitive manner, and it also exerts suppressive effects on both R5- and CXCR4-dependent HIV expression at a less-characterized postentry level. We demonstrate in this study that PTX-B profoundly inhibits HIV expression in chronically infected promonocytic U1 cells stimulated with several cytokines and, particularly, the IL-6-mediated effect, a cytokine that triggers viral production in these cells independently of NF-kappaB activation. From U1 cells we have subcloned a cell line, named U1-CR1, with increased responsiveness to IL-6. In these cells, PTX-B neither down-regulated the IL-6R nor prevented IL-6 induced signaling in terms of STAT3 phosphorylation and DNA binding. In contrast, PTX-B inhibited AP-1 binding to target DNA and modified its composition with a proportional increases in FosB, Fra2, and ATF2. PTX-B inhibited IL-6-induced HIV-1 long-terminal repeat-driven transcription from A, C, E, and F viral subtypes, which contain functional AP-1 binding sites, but failed to inhibit transcription from subtypes B and D LTR devoid of these sites. In addition, PTX-B inhibited the secretion of IL-6-induced, AP-1-dependent genes, including urokinase-type plasminogen activator, CXCL8/IL-8, and CCL2/monocyte chemotactic protein-1. Thus, PTX-B suppression of IL-6 induced expression of HIV and cellular genes in chronically infected promonocytic cells is strongly correlated to inhibition of AP-1.
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Affiliation(s)
- Chiara Rizzi
- AIDS Immunopathogenesis Unit, San Raffaele Scientific Institute, Milan, Italy
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108
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Arlen PA, Brooks DG, Gao LY, Vatakis D, Brown HJ, Zack JA. Rapid expression of human immunodeficiency virus following activation of latently infected cells. J Virol 2006; 80:1599-603. [PMID: 16415036 PMCID: PMC1346949 DOI: 10.1128/jvi.80.3.1599-1603.2006] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The host cell activation state impacts the nature of human immunodeficiency virus infection. Activated cells facilitate productive infections; quiescent cells enable the virus to enter a latent state, the major obstacle to viral clearance. We wanted to understand how these differences affected viral gene expression. In quiescent cells activated prior to infection, viral RNA was seen 12 h postinfection; when cells were stimulated postinfection, viral RNA was not seen until 36 h postinfection. Up-regulation of viral RNA in latently infected cells occurred within 2 h poststimulation. This hierarchy also held true for viral protein production. These results may explain the rapid reemergence of viremia following termination of therapy.
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Affiliation(s)
- Philip A Arlen
- David Geffen School of Medicine, University of California-Los Angeles, 11-934 Factor Building, 650 Charles Young Drive South, Los Angeles, CA 90095, USA
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109
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Munier S, Delcroix-Genête D, Carthagéna L, Gumez A, Hazan U. Characterization of two candidate genes, NCoA3 and IRF8, potentially involved in the control of HIV-1 latency. Retrovirology 2005; 2:73. [PMID: 16305739 PMCID: PMC1310520 DOI: 10.1186/1742-4690-2-73] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2005] [Accepted: 11/23/2005] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND The persistence of latent HIV-1 reservoirs is the principal barrier preventing the eradication of HIV-1 infection in patients by current antiretroviral therapy. It is thus crucial to understand the molecular mechanisms involved in the establishment, maintenance and reactivation of HIV-1 latency. Since chromatin remodeling has been implicated in the transcriptional reactivation of the HIV-1 promoter, we assessed the role of the histone deacetylase inhibitor sodium butyrate (NaB) on two HIV-1 latently infected cell lines (U1 and ACH-2) gene expression. RESULTS Analysis of microarrays data led us to select two candidate genes: NCoA3 (Nuclear Receptor Coactivator 3), a nuclear receptor coactivator and IRF8 (Interferon Regulatory Factor 8), an interferon regulatory factor. NCoA3 gene expression is upregulated following NaB treatment of latently infected cells whereas IRF8 gene expression is strongly downregulated in the promonocytic cell line following NaB treatment. Their differential expressions were confirmed at the transcriptional and translational levels. Moreover, NCoA3 gene expression was also upregulated after treatment of U1 and ACH-2 cells with phorbol myristyl acetate (PMA) but not trichostatin A (TSA) and after treatment with NaB of two others HIV-1 latently infected cell lines (OM10.1 and J1.1). IRF8 gene is only expressed in U1 cells and was also downregulated after treatment with PMA or TSA. Functional analyses confirmed that NCoA3 synergizes with Tat to enhance HIV-1 promoter transcription and that IRF8 represses the IRF1-mediated activation through the HIV-1 promoter Interferon-stimulated response element (ISRE). CONCLUSION These results led us to postulate that NCoA3 could be involved in the transcriptional reactivation of the HIV-1 promoter from latency and that IRF8 may contribute to the maintenance of the latent state in the promonocytic cell line. Implication of these factors in the maintenance or reactivation of the viral latency may provide potential new targets to control HIV-1 replication in latent viral reservoirs.
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Affiliation(s)
- Sandie Munier
- Département des Maladies Infectieuses, Institut Cochin, INSERM U567/CNRS UMR-S 8104/Université Paris 5-René Descartes, 22 rue Méchain, 75014 Paris, France
| | - Delphine Delcroix-Genête
- Département des Maladies Infectieuses, Institut Cochin, INSERM U567/CNRS UMR-S 8104/Université Paris 5-René Descartes, 22 rue Méchain, 75014 Paris, France
| | - Laëtitia Carthagéna
- Département des Maladies Infectieuses, Institut Cochin, INSERM U567/CNRS UMR-S 8104/Université Paris 5-René Descartes, 22 rue Méchain, 75014 Paris, France
| | - Audrey Gumez
- Département des Maladies Infectieuses, Institut Cochin, INSERM U567/CNRS UMR-S 8104/Université Paris 5-René Descartes, 22 rue Méchain, 75014 Paris, France
| | - Uriel Hazan
- Département des Maladies Infectieuses, Institut Cochin, INSERM U567/CNRS UMR-S 8104/Université Paris 5-René Descartes, 22 rue Méchain, 75014 Paris, France
- UFR de Biochimie, Université Paris 7-Denis Diderot, 2 Place Jussieu, 75251 Paris, France
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110
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Abstract
A recent study has provided important clues towards the identity of the host genes that conspire to promote post-integration latency of human immunodeficiency virus (HIV). Various genes controlling transcription, histone deacetylation and proteasome-mediated protein degradation have emerged as potential players. If the desired, but difficult, goal of complete virus eradication in HIV-infected patients is ever to be realized, the latent reservoir of HIV proviruses must be cleared. Understanding the molecular basis for viral latency is the key first step.
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Affiliation(s)
- Samuel A F Williams
- Gladstone Institute of Virology and Immunology, 1650 Owens Street, San Francisco, CA 94158, USA
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111
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Pagans S, Pedal A, North BJ, Kaehlcke K, Marshall BL, Dorr A, Hetzer-Egger C, Henklein P, Frye R, McBurney MW, Hruby H, Jung M, Verdin E, Ott M. SIRT1 regulates HIV transcription via Tat deacetylation. PLoS Biol 2005; 3:e41. [PMID: 15719057 PMCID: PMC546329 DOI: 10.1371/journal.pbio.0030041] [Citation(s) in RCA: 265] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2004] [Accepted: 12/01/2004] [Indexed: 12/11/2022] Open
Abstract
The human immunodeficiency virus (HIV) Tat protein is acetylated by the transcriptional coactivator p300, a necessary step in Tat-mediated transactivation. We report here that Tat is deacetylated by human sirtuin 1 (SIRT1), a nicotinamide adenine dinucleotide-dependent class III protein deacetylase in vitro and in vivo. Tat and SIRT1 coimmunoprecipitate and synergistically activate the HIV promoter. Conversely, knockdown of SIRT1 via small interfering RNAs or treatment with a novel small molecule inhibitor of the SIRT1 deacetylase activity inhibit Tat-mediated transactivation of the HIV long terminal repeat. Tat transactivation is defective in SIRT1-null mouse embryonic fibroblasts and can be rescued by expression of SIRT1. These results support a model in which cycles of Tat acetylation and deacetylation regulate HIV transcription. SIRT1 recycles Tat to its unacetylated form and acts as a transcriptional coactivator during Tat transactivation. Cycles of Tat acetylation and deacetylation, mediated by human sirtuin 1 (SIRT1), regulate HIV transcription suggesting that SIRT1 could be a therapeutic target
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Affiliation(s)
- Sara Pagans
- 1Gladstone Institute of Virology and Immunology, University of CaliforniaSan Francisco, CaliforniaUnited States of America
| | - Angelika Pedal
- 1Gladstone Institute of Virology and Immunology, University of CaliforniaSan Francisco, CaliforniaUnited States of America
| | - Brian J North
- 1Gladstone Institute of Virology and Immunology, University of CaliforniaSan Francisco, CaliforniaUnited States of America
| | - Katrin Kaehlcke
- 1Gladstone Institute of Virology and Immunology, University of CaliforniaSan Francisco, CaliforniaUnited States of America
| | - Brett L Marshall
- 1Gladstone Institute of Virology and Immunology, University of CaliforniaSan Francisco, CaliforniaUnited States of America
| | - Alexander Dorr
- 2Applied Tumorvirology, Deutsches KrebsforschungszentrumHeidelbergGermany
| | | | - Peter Henklein
- 3Institute of Biochemistry, Humboldt UniversityBerlinGermany
| | - Roy Frye
- 4Department of Pathology, University of PittsburghPittsburgh, PennsylvaniaUnited States of America
| | | | - Henning Hruby
- 6Department of Pharmaceutical Sciences, Albert-Ludwigs-UniversityFreiburgGermany
| | - Manfred Jung
- 6Department of Pharmaceutical Sciences, Albert-Ludwigs-UniversityFreiburgGermany
| | - Eric Verdin
- 1Gladstone Institute of Virology and Immunology, University of CaliforniaSan Francisco, CaliforniaUnited States of America
| | - Melanie Ott
- 1Gladstone Institute of Virology and Immunology, University of CaliforniaSan Francisco, CaliforniaUnited States of America
- 2Applied Tumorvirology, Deutsches KrebsforschungszentrumHeidelbergGermany
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112
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Thierry S, Marechal V, Rosenzwajg M, Sabbah M, Redeuilh G, Nicolas JC, Gozlan J. Cell cycle arrest in G2 induces human immunodeficiency virus type 1 transcriptional activation through histone acetylation and recruitment of CBP, NF-kappaB, and c-Jun to the long terminal repeat promoter. J Virol 2004; 78:12198-206. [PMID: 15507606 PMCID: PMC525107 DOI: 10.1128/jvi.78.22.12198-12206.2004] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In human immunodeficiency virus type 1 (HIV-1)-infected cells, a cell cycle arrest in G(2) increases viral expression and may represent a strategy for the virus to optimize its expression. In latently infected cells, balance between viral silencing and reactivation relies on the nucleosomal organization of the integrated long terminal repeat (LTR). It is shown here that nucleosome nuc-1, which is located downstream of the TATA box, is specifically modified when latently infected cells are arrested in G(2) by chemical inducers. Notably, histones H3 and H4 are hyperacetylated, and this modification is associated with an increased LTR-driven transcription. nuc-1 hyperacetylation is also associated with the recruitment of histone acetyltransferase CBP and transcription factors NF-kappaB and c-Jun. NF-kappaB and/or c-Jun binding to the LTR in G(2)-arrested cells appears to be required for CBP recruitment as well as for nuc-1 remodeling and viral reactivation.
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Affiliation(s)
- Sylvain Thierry
- UMR 7079, Université Pierre et Marie Curie, 7 quai Saint-Bernard, 75005 Paris, France
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113
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Demonté D, Quivy V, Colette Y, Van Lint C. Administration of HDAC inhibitors to reactivate HIV-1 expression in latent cellular reservoirs: implications for the development of therapeutic strategies. Biochem Pharmacol 2004; 68:1231-8. [PMID: 15313421 DOI: 10.1016/j.bcp.2004.05.040] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2004] [Accepted: 05/07/2004] [Indexed: 12/11/2022]
Abstract
The discovery of powerful antiviral compounds in the 90's raised the hope that the human immunodeficiency virus type 1 (HIV-1) might be eradicated. However, if these drugs succeed in decreasing and controlling viral replication, complete eradication of the virus is nowadays impossible. The persistence of virus even after long periods of highly active antiretroviral therapy (HAART) mainly results from the presence of cellular reservoirs that contain transcriptionally competent latent viruses capable of producing infectious particles after cellular activation. These latently infected cells are a permanent source for virus reactivation and lead to a rebound of the viral load after interruption of HAART. Activation of HIV gene expression in these cells combined with an effective HAART has been proposed as an adjuvant therapy that could lead to the elimination of the latently infected cells and then to the eradication of the infection. In this context, we have previously demonstrated that deacetylase inhibitors (HDACi) synergize with TNF-induced NF-kappaB to activate the HIV-1 promoter. The physiological relevance of the TNF/HDACi synergism was shown on HIV-1 replication in both acutely and latently HIV-infected cell lines. Based on these results, we propose the administration of deacetylase inhibitor(s) together with continuous HAART as a new potential therapeutic perspective to decrease the pool of latent HIV reservoirs by forcing viral expression.
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Affiliation(s)
- Dominique Demonté
- Laboratoire de Virologie Moléculaire, Service de Chimie Biologique rue des Profs Jeener et Brachet 12, Institut de Biologie et de Médecine Moléculaires, Université Libre de Bruxelles, 6041 Gosselies, Belgium
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114
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Brooks DG, Arlen PA, Gao L, Kitchen CMR, Zack JA. Identification of T cell-signaling pathways that stimulate latent HIV in primary cells. Proc Natl Acad Sci U S A 2003; 100:12955-60. [PMID: 14569007 PMCID: PMC240726 DOI: 10.1073/pnas.2233345100] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2003] [Accepted: 09/02/2003] [Indexed: 11/18/2022] Open
Abstract
Eradication of HIV infection depends on the elimination of a small, but stable population of latently infected T cells. After the discontinuation of therapy, activation of latent virus can rekindle infection. To purge this reservoir, it is necessary to define cellular signaling pathways that lead to activation of latent HIV. We used the SCID-hu (Thy/Liv) mouse model of HIV latency to analyze a broad array of T cell-signaling pathways and show in primary, quiescent cells that viral induction depends on the activation of two primary intracellular signaling pathways, protein kinase C or nuclear factor of activated T cells (NF-AT). In contrast, inhibition or activation of other important T cell stimulatory pathways (such as mitogen-activated protein kinase, calcium flux, or histone deacetylation) do not significantly induce virus expression. We found that the activation of NF-kappaB is critical to viral reactivation; however, all pathways that stimulate NF-kappaBdonot reactivate latent virus. Our studies further show that inhibition of NF-kappaB does not prevent activation of HIV by NF-AT, indicating that these pathways can function independently to activate the HIV LTR. Thus, we define several molecular pathways that trigger HIV reactivation from latency and provide evidence that latent HIV infection is maintained by the functional lack of particular transcription factors in quiescent cells.
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Affiliation(s)
- David G Brooks
- Department of Microbiology, Immunology, and Molecular Genetics, David Geffen School of Medicine, University of California-Los Angeles, 10833 LeConte Avenue, Los Angeles, CA 90095, USA
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115
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Reza SM, Rosetti M, Mathews MB, Pe'ery T. Differential activation of Tat variants in mitogen-stimulated cells: implications for HIV-1 postintegration latency. Virology 2003; 310:141-56. [PMID: 12788638 DOI: 10.1016/s0042-6822(03)00106-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Like other HIV-1 (human immunodeficiency virus type 1) proteins, Tat undergoes rapid mutation and occurs in numerous sequence variants in nature. Virus isolated from patients often has defects in Tat that lower its activity. The levels of P-TEFb, an essential cellular cofactor for Tat, are elevated by T-cell activation. To test the hypothesis that stimulation of P-TEFb levels might compensate for attenuation of Tat activity, we generated Tat constructs with a range of transactivation function. Transactivation by the Tat mutants correlated with their ability to bind to P-TEFb in vitro. Treatment of U937 cells with the phorbol ester PMA (phorbol myristate acetate) induced P-TEFb and stimulated Tat transactivation for alleles with basal transcription activity above a threshold (>5% compared to wild-type). Highly active alleles (>66% of wild-type) were stimulated to a lesser extent than those with activity in the intermediate range. Thus, attenuation of Tat function, in concert with low levels of P-TEFb activity, could serve to keep the virus in a latent state in quiescent cells yet permit viral replication after cell activation.
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Affiliation(s)
- Syed M Reza
- Department of Biochemistry and Molecular Biology, New Jersey Medical School, University of Medicine and Dentistry of New Jersey, Newark, NJ 07103-1709, USA
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116
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Jordan A, Bisgrove D, Verdin E. HIV reproducibly establishes a latent infection after acute infection of T cells in vitro. EMBO J 2003; 22:1868-77. [PMID: 12682019 PMCID: PMC154479 DOI: 10.1093/emboj/cdg188] [Citation(s) in RCA: 712] [Impact Index Per Article: 33.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
The presence of latent reservoirs has prevented the eradication of human immunodeficiency virus (HIV) from infected patients successfully treated with anti-retroviral therapy. The mechanism of postintegration latency is poorly understood, partly because of the lack of an in vitro model. We have used an HIV retroviral vector or a full-length HIV genome expressing green fluorescent protein to infect a T lymphocyte cell line in vitro and highly enrich for latently infected cells. HIV latency occurred reproducibly, albeit with low frequency, during an acute infection. Clonal cell lines derived from latent populations showed no detectable basal expression, but could be transcriptionally activated after treatment with phorbol esters or tumor necrosis factor alpha. Direct sequencing of integration sites demonstrated that latent clones frequently contain HIV integrated in or close to alphoid repeat elements in heterochromatin. This is in contrast to a productive infection where integration in or near heterochromatin is disfavored. These observations demonstrate that HIV can reproducibly establish a latent infection as a consequence of integration in or near heterochromatin.
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Affiliation(s)
- Albert Jordan
- Department of Medicine, University of California, San Francisco, CA 94141, USA
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117
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Lane BR, King SR, Bock PJ, Strieter RM, Coffey MJ, Markovitz DM. The C-X-C chemokine IP-10 stimulates HIV-1 replication. Virology 2003; 307:122-34. [PMID: 12667820 DOI: 10.1016/s0042-6822(02)00045-4] [Citation(s) in RCA: 94] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Chemokines play critical roles in HIV-1 infection, serving both to modulate viral replication and to recruit target cells to sites of infection. Interferon-gamma-inducible protein 10 (IP-10/CXCL10) is a C-X-C chemokine that acts specifically upon activated T cells and macrophages and attracts T cells into the cerebrospinal fluid (CSF) in HIV-associated neurological disease. We now demonstrate that IP-10 stimulates HIV-1 replication in monocyte-derived macrophages and peripheral blood lymphocytes. We further demonstrate that neutralization of endogenous IP-10 or blocking the function of its receptor, CXCR3, reduces HIV-1 replication in these same cells. Therefore, blocking the interaction between IP-10 and CXCR3 represents a possible new target for anti-retroviral therapy.
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Affiliation(s)
- Brian R Lane
- Division of Infectious Diseases, Department of Internal Medicine, University of Michigan Medical Center, 1150 West Medical Center Drive, Ann Arbor, MI 48109-0640, USA
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118
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Peterlin BM, Trono D. Hide, shield and strike back: how HIV-infected cells avoid immune eradication. Nat Rev Immunol 2003; 3:97-107. [PMID: 12563294 DOI: 10.1038/nri998] [Citation(s) in RCA: 103] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Viruses that induce chronic infections can evade immune responses. HIV is a prototype of this class of pathogen. Not only does it mutate rapidly and make its surface components difficult to access by neutralizing antibodies, but it also creates cellular hideouts, establishes proviral latency, removes cell-surface receptors and destroys immune effectors to escape eradication. A better understanding of these strategies might lead to new approaches in the fight against AIDS.
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Affiliation(s)
- B Matija Peterlin
- Department of Medicine, Rosalind Russell Medical Research Center, University of California, San Francisco, California 94143-0703, USA.
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119
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Sonza S, Mutimer HP, O'Brien K, Ellery P, Howard JL, Axelrod JH, Deacon NJ, Crowe SM, Purcell DFJ. Selectively reduced tat mRNA heralds the decline in productive human immunodeficiency virus type 1 infection in monocyte-derived macrophages. J Virol 2002; 76:12611-21. [PMID: 12438587 PMCID: PMC136686 DOI: 10.1128/jvi.76.24.12611-12621.2002] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The transcription and splicing of human immunodeficiency virus type 1 (HIV-1) mRNA in primary blood monocyte-derived macrophages (MDM) and CD4(+) peripheral blood lymphocytes (PBL) were compared to determine whether any differences might account for the slower noncytopathic infection of cells of the macrophage lineage. The expression of regulatory mRNAs during acute infection of MDM was delayed by about 12 h compared to that of PBL. In each cell type, an increase in spliced viral mRNAs slightly preceded virus production from the culture. Following the peak of productive infection, there was a proportional decrease in the expression of all regulatory mRNAs detected in PBL. In MDM, a dramatic additional decrease specifically in the tat mRNA species heralded a reduction in virus production. This decline in tat mRNA was reflected by a concomitant decrease in Tat activity in the cells and occurred with the same kinetics irrespective of the age of the cells when infected. Addition of exogenous Tat protein elicited a burst of virus production from persistently infected MDM, suggesting that the decrease in virus production from the cultures is a consequence of the reduction in tat mRNA levels. Our results show that modulation of HIV-1 mRNAs in macrophages during long-term infection, which is dependent on the period of infection rather than cell differentiation or maturation, results in a selective reduction of Tat protein levels at the commencement of a persistent, less productive phase of infection. Determination of the mechanism of this mRNA modulation may lead to novel targets for control of replication in these important viral reservoirs.
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Affiliation(s)
- Secondo Sonza
- AIDS Pathogenesis Research Unit, Macfarlane Burnet Institute for Medical Research and Public Health, G.P.O. Box 2284, Melbourne, Victoria 3004, Australia.
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120
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Quivy V, Adam E, Collette Y, Demonte D, Chariot A, Vanhulle C, Berkhout B, Castellano R, de Launoit Y, Burny A, Piette J, Bours V, Van Lint C. Synergistic activation of human immunodeficiency virus type 1 promoter activity by NF-kappaB and inhibitors of deacetylases: potential perspectives for the development of therapeutic strategies. J Virol 2002; 76:11091-103. [PMID: 12368351 PMCID: PMC136606 DOI: 10.1128/jvi.76.21.11091-11103.2002] [Citation(s) in RCA: 108] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The transcription factor NF-kappaB plays a central role in the human immunodeficiency virus type 1 (HIV-1) activation pathway. HIV-1 transcription is also regulated by protein acetylation, since treatment with deacetylase inhibitors such as trichostatin A (TSA) or sodium butyrate (NaBut) markedly induces HIV-1 transcriptional activity of the long terminal repeat (LTR) promoter. Here, we demonstrate that TSA (NaBut) synergized with both ectopically expressed p50/p65 and tumor necrosis factor alpha/SF2 (TNF)-induced NF-kappaB to activate the LTR. This was confirmed for LTRs from subtypes A through G of the HIV-1 major group, with a positive correlation between the number of kappaB sites present in the LTRs and the amplitude of the TNF-TSA synergism. Mechanistically, TSA (NaBut) delayed the cytoplasmic recovery of the inhibitory protein IkappaBalpha. This coincided with a prolonged intranuclear presence and DNA binding activity of NF-kappaB. The physiological relevance of the TNF-TSA (NaBut) synergism was shown on HIV-1 replication in both acutely and latently HIV-infected cell lines. Therefore, our results open new therapeutic strategies aimed at decreasing or eliminating the pool of latently HIV-infected reservoirs by forcing viral expression.
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Affiliation(s)
- Vincent Quivy
- Laboratoire de Virologie Moléculaire, Service de Chimie Biologique, Institut de Biologie et de Médecine Moléculaires, Université Libre de Bruxelles, 6041 Gosselies, Belgium
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121
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Kutsch O, Benveniste EN, Shaw GM, Levy DN. Direct and quantitative single-cell analysis of human immunodeficiency virus type 1 reactivation from latency. J Virol 2002; 76:8776-86. [PMID: 12163598 PMCID: PMC136999 DOI: 10.1128/jvi.76.17.8776-8786.2002] [Citation(s) in RCA: 145] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2001] [Accepted: 05/21/2002] [Indexed: 11/20/2022] Open
Abstract
The ability of human immunodeficiency virus type 1 (HIV-1) to establish latent infections in cells has received renewed attention owing to the failure of highly active antiretroviral therapy to eradicate HIV-1 in vivo. Despite much study, the molecular bases of HIV-1 latency and reactivation are incompletely understood. Research on HIV-1 latency would benefit from a model system that is amenable to rapid and efficient analysis and through which compounds capable of regulating HIV-1 reactivation may be conveniently screened. We describe a novel reporter system that has several advantages over existing in vitro systems, which require elaborate, expensive, and time-consuming techniques to measure virus production. Two HIV-1 molecular clones (NL4-3 and 89.6) were engineered to express enhanced green fluorescent protein (EGFP) under the control of the viral long terminal repeat without removing any viral sequences. By using these replication-competent viruses, latently infected T-cell (Jurkat) and monocyte/macrophage (THP-1) lines in which EGFP fluorescence and virus expression are tightly coupled were generated. Following reactivation with agents such as tumor necrosis factor alpha, virus expression and EGFP fluorescence peaked after 4 days and over the next 3 weeks each declined in a synchronized manner, recapitulating the establishment of latency. Using fluorescence microscopy, flow cytometry, or plate-based fluorometry, this system allows immediate, direct, and quantitative real-time analysis of these processes within single cells or in bulk populations of cells. Exploiting the single-cell analysis abilities of this system, we demonstrate that cellular activation and virus reactivation following stimulation with proinflammatory cytokines can be uncoupled.
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Affiliation(s)
- Olaf Kutsch
- Department of Cell Biology, The University of Alabama at Birmingham, Birmingham, Alabama 35294, USA
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122
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Dorr A, Kiermer V, Pedal A, Rackwitz HR, Henklein P, Schubert U, Zhou MM, Verdin E, Ott M. Transcriptional synergy between Tat and PCAF is dependent on the binding of acetylated Tat to the PCAF bromodomain. EMBO J 2002; 21:2715-23. [PMID: 12032084 PMCID: PMC125383 DOI: 10.1093/emboj/21.11.2715] [Citation(s) in RCA: 118] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The human immunodeficiency virus (HIV) Tat protein plays an essential role in promoting efficient transcriptional elongation of viral transcripts. We report that the transcriptional co-activator PCAF and Tat interact and synergize to activate the HIV promoter. The binding of Tat and PCAF in vitro and in vivo is dependent on the acetylated state of Lys50 of Tat and on the PCAF bromodomain. Structural analysis of the acetylated Tat peptide bound to the PCAF bromodomain defined amino acids Y47 and R53 in Tat and V763, Y802, and Y809 in PCAF as critical interaction points between the two proteins. Mutation of each of these residues in either Tat or PCAF inhibited in a cumulative manner the Tat-PCAF interaction in vitro and in vivo, and abrogated the synergistic activation of the HIV promoter by both proteins. These observations demonstrate that acetylation of Tat establishes a novel protein-protein interaction domain at the surface of Tat that is necessary for the transcriptional activation of the HIV promoter.
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Affiliation(s)
| | - Veronique Kiermer
- Deutsches Krebsforschungszentrum (DKFZ), 69120 Heidelberg,
Humboldt University, Institute of Biochemistry, D-10115 Berlin, Germany, Gladstone Institute of Virology and Immunology, University of California, San Francisco, CA 94141, Laboratory of Viral Diseases, National Institutes of Health, Bethesda, MD 20892 and Structural Biology Program, Department of Physiology and Biophysics, Mount Sinai School of Medicine, New York,NY 10029-6574, USA Corresponding author e-mail: A.Dorr and V.Kiermer contributed equally to this work
| | | | | | - Peter Henklein
- Deutsches Krebsforschungszentrum (DKFZ), 69120 Heidelberg,
Humboldt University, Institute of Biochemistry, D-10115 Berlin, Germany, Gladstone Institute of Virology and Immunology, University of California, San Francisco, CA 94141, Laboratory of Viral Diseases, National Institutes of Health, Bethesda, MD 20892 and Structural Biology Program, Department of Physiology and Biophysics, Mount Sinai School of Medicine, New York,NY 10029-6574, USA Corresponding author e-mail: A.Dorr and V.Kiermer contributed equally to this work
| | - Ulrich Schubert
- Deutsches Krebsforschungszentrum (DKFZ), 69120 Heidelberg,
Humboldt University, Institute of Biochemistry, D-10115 Berlin, Germany, Gladstone Institute of Virology and Immunology, University of California, San Francisco, CA 94141, Laboratory of Viral Diseases, National Institutes of Health, Bethesda, MD 20892 and Structural Biology Program, Department of Physiology and Biophysics, Mount Sinai School of Medicine, New York,NY 10029-6574, USA Corresponding author e-mail: A.Dorr and V.Kiermer contributed equally to this work
| | - Ming-Ming Zhou
- Deutsches Krebsforschungszentrum (DKFZ), 69120 Heidelberg,
Humboldt University, Institute of Biochemistry, D-10115 Berlin, Germany, Gladstone Institute of Virology and Immunology, University of California, San Francisco, CA 94141, Laboratory of Viral Diseases, National Institutes of Health, Bethesda, MD 20892 and Structural Biology Program, Department of Physiology and Biophysics, Mount Sinai School of Medicine, New York,NY 10029-6574, USA Corresponding author e-mail: A.Dorr and V.Kiermer contributed equally to this work
| | - Eric Verdin
- Deutsches Krebsforschungszentrum (DKFZ), 69120 Heidelberg,
Humboldt University, Institute of Biochemistry, D-10115 Berlin, Germany, Gladstone Institute of Virology and Immunology, University of California, San Francisco, CA 94141, Laboratory of Viral Diseases, National Institutes of Health, Bethesda, MD 20892 and Structural Biology Program, Department of Physiology and Biophysics, Mount Sinai School of Medicine, New York,NY 10029-6574, USA Corresponding author e-mail: A.Dorr and V.Kiermer contributed equally to this work
| | - Melanie Ott
- Deutsches Krebsforschungszentrum (DKFZ), 69120 Heidelberg,
Humboldt University, Institute of Biochemistry, D-10115 Berlin, Germany, Gladstone Institute of Virology and Immunology, University of California, San Francisco, CA 94141, Laboratory of Viral Diseases, National Institutes of Health, Bethesda, MD 20892 and Structural Biology Program, Department of Physiology and Biophysics, Mount Sinai School of Medicine, New York,NY 10029-6574, USA Corresponding author e-mail: A.Dorr and V.Kiermer contributed equally to this work
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123
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Interleukin-6 and Glucocorticoids Synergistically Induce Human Immunodeficiency Virus Type-1 Expression in Chronically Infected U1 Cells by a Long Terminal Repeat Independent Post-Transcriptional Mechanism. Mol Med 2001. [DOI: 10.1007/bf03401957] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022] Open
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124
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McGrath KM, Hoffman NG, Resch W, Nelson JA, Swanstrom R. Using HIV-1 sequence variability to explore virus biology. Virus Res 2001; 76:137-60. [PMID: 11410314 DOI: 10.1016/s0168-1702(01)00271-4] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Human immunodeficiency virus type 1 (HIV-1) only recently established an epidemic world-wide infection in the human population. The virus persists in the human host through active replication and is able to avoid clearance by the immune system. Active replication is an important component of the rapid evolutionary potential of HIV-1, a potential which manifests itself in the evolution of immune escape variants, drug resistant variants, and variants with the ability to use different cell surface coreceptors in conjunction with CD4. Multiple zoonotic introductions, compartmentalization of virus replication in the body, and genetic bottlenecks associated with sampling during transmission, antiretroviral therapy, and geographic and/or host population isolation further contribute to the range of sequences present in extant viruses. The sum of the history of all of these phenomena is reflected in HIV-1 sequence variability, and most of these phenomena are ongoing today. Here we review the use of HIV-1 sequence variability to explore its underlying biology.
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Affiliation(s)
- K M McGrath
- UNC Center for AIDS Research, University of North Carolina at Chapel Hill, 22-062 Lineberger Cancer Center, CB# 7295, Chapel Hill, NC 27599-7295, USA
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125
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Hung CL, Doniger J, Palini A, Snyder SW, Radonovich MF, Brady JN, Pantazis P, Sadaie MR. 9-Nitrocamptothecin inhibits HIV-1 replication in human peripheral blood lymphocytes: a potential alternative for HIV-infection/AIDS therapy. J Med Virol 2001; 64:238-44. [PMID: 11424110 DOI: 10.1002/jmv.1042] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The ability of the anti-cancer drug, 9-Nitrocamptothecin (9NC), to inhibit replication of HIV-1 in clinically relevant primary lymphocytic cells was studied. Primary peripheral blood lymphocytes (PBLs) from a non-infected donor were freshly infected with HIV-1 and treated with 9NC by using three different treatment schedules. Cells were monitored for cytotoxicity by the XTT metabolic cell proliferation assay and a sensitive flow cytometric assay that was capable of measuring cell cycle changes and apoptosis. 9NC inhibited replication of HIV-1 in PBLs by greater than 95% in a dose-dependent manner as measured by the level of extracellular HIV-1 p24 release. Similar results were observed, whether 9NC was applied in a single, double, or triple dose regimen. Minimal cytotoxicity was observed for both non-infected and infected PBLs, as determined by the XTT assay. Moreover, 9NC induced apoptosis within 24 hours of drug treatment in freshly infected, but not non-infected, PBLs. The data showed that 9NC reduced replication of HIV-1 in primary human lymphocytes; thus, it indicates the potential clinical utility of this drug as an alternative or adjunct therapy for HIV-infection/AIDS.
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Affiliation(s)
- C L Hung
- Advanced Bioscience Laboratories, Inc., Kensington, Maryland, USA
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126
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Affiliation(s)
- B Berkhout
- Department of Human Retrovirology, Academic Medical Center, University of Amsterdam, 1105 AZ Amsterdam, Netherlands
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127
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Jordan A, Defechereux P, Verdin E. The site of HIV-1 integration in the human genome determines basal transcriptional activity and response to Tat transactivation. EMBO J 2001; 20:1726-38. [PMID: 11285236 PMCID: PMC145503 DOI: 10.1093/emboj/20.7.1726] [Citation(s) in RCA: 364] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Because of the heterogeneity of chromatin, the site of integration of human immunodeficiency virus (HIV) in the genome could have dramatic effects on its transcriptional activity. We have used an HIV-1-derived retroviral vector, in which the green fluorescent protein is under the control of the HIV promoter, to generate by infection 34 Jurkat clonal cell lines each containing a single integration of the HIV-1 vector. In the absence of Tat, a 75-fold difference in expression level between the highest and lowest expressing clones was observed. Basal promoter activity was low in 80% of the clones and moderate to high in the remaining 20% of clones. We found that differences in expression levels are due to the integration site and are not controlled by DNA methylation or histone acetylation. Tat activated transcription in each clone, and an inverse correlation was observed between basal transcriptional activity and inducibility by Tat. These observations demonstrate that the chromatin environment influences basal HIV gene expression and that the HIV Tat protein activates transcription independently of the chromatin environment.
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Affiliation(s)
- Albert Jordan
- Gladstone Institute of Virology and Immunology and Department of Medicine, University of California, San Francisco, CA 94141, USA Corresponding author e-mail:
| | - Patricia Defechereux
- Gladstone Institute of Virology and Immunology and Department of Medicine, University of California, San Francisco, CA 94141, USA Corresponding author e-mail:
| | - Eric Verdin
- Gladstone Institute of Virology and Immunology and Department of Medicine, University of California, San Francisco, CA 94141, USA Corresponding author e-mail:
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128
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Alfano M, Vallanti G, Biswas P, Bovolenta C, Vicenzi E, Mantelli B, Pushkarsky T, Rappuoli R, Lazzarin A, Bukrinsky M, Poli G. The binding subunit of pertussis toxin inhibits HIV replication in human macrophages and virus expression in chronically infected promonocytic U1 cells. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2001; 166:1863-70. [PMID: 11160233 DOI: 10.4049/jimmunol.166.3.1863] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
We have recently shown that the binding subunit of pertussis toxin (PTX-B) inhibits the entry and replication of macrophage-tropic (R5) HIV-1 strains in activated primary T lymphocytes. Furthermore, PTX-B suppressed the replication of T cell-tropic (X4) viruses at a postentry level in the same cells. In this study we demonstrate that PTX-B profoundly impairs entry and replication of the HIV-1(ADA) (R5), as well as of HIV pseudotyped with either murine leukemia virus or vesicular stomatitis virus envelopes, in primary monocyte-derived macrophages. In addition, PTX-B strongly inhibited X4 HIV-1 replication in U937 promonocytic cells and virus expression in the U937-derived chronically infected U1 cell line stimulated with cytokines such as TNF-alpha and IL-6. Of interest, TNF-alpha-mediated activation of the cellular transcription factor NF-kappaB was unaffected by PTX-B. Therefore, PTX-B may represent a novel and potent inhibitor of HIV-1 replication to be tested for efficacy in infected individuals. In support of this proposition, a genetically modified mutant of PTX (PT-9K/129G), which is safely administered for prevention of Bordetella pertussis infection, showed an in vitro anti-HIV profile superimposable to that of PTX-B.
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Affiliation(s)
- M Alfano
- AIDS Immunopathogenesis Unit, Department of Biology and Technology, and Laboratory of Clinical Immunology, Division of Infectious Diseases, San Raffaele Scientific Institute, Milan, Italy.
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129
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Butera ST. Therapeutic targeting of human immunodeficiency virus type-1 latency: current clinical realities and future scientific possibilities. Antiviral Res 2000; 48:143-76. [PMID: 11164503 DOI: 10.1016/s0166-3542(00)00133-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Factors affecting HIV-1 latency present formidable obstacles for therapeutic intervention. As these obstacles have become a clinical reality, even with the use of potent anti-retroviral regimens, the need for novel therapeutic strategies specifically targeting HIV-1 latency is evident. However, therapeutic targeting of HIV-1 latency requires an understanding of the mechanisms regulating viral quiescence and activation. These mechanisms have been partially delineated using chronically infected cell models and, clearly, HIV-1 activation from latency involves several key viral and cellular components. Among these distinctive therapeutic targets, cellular factors involved in HIV-1 transcription especially warrant further consideration for rational drug design. Exploring the scientific possibilities of new therapies targeting HIV-1 latency may hold new promise of eventual HIV-1 eradication.
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Affiliation(s)
- S T Butera
- HIV and Retrovirology Branch, Division of AIDS, STD, and TB Laboratory Research, National Center for Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, GA 30333, USA.
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130
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Adams M, Wong C, Wang D, Romeo J. Limitation of Tat-associated transcriptional processivity in HIV-infected PBMC. Virology 1999; 257:397-405. [PMID: 10329550 DOI: 10.1006/viro.1999.9647] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The ability of HIV to match levels of viral mRNA to the activation state of the host cell may play a role in its ability to persist as well as to replicate. This linkage depends on the function of the viral transcriptional regulatory protein, Tat, which increases the efficiency of RNA elongation (transcriptional processivity) in response to cellular activation. To quantify levels of Tat function in vivo, a quantitative competitive RT-PCR assay was developed that reflects levels of TAR leader fragments (nonprocessive transcripts) and viral mRNA (processive transcripts), indicating low or high levels of Tat function, respectively. The abundance of these RNA species was measured in peripheral blood mononuclear cells (PBMC) of 22 HIV-1-positive individuals (CD4(+) T cell counts 63-934/mm3) and in established cell line models of HIV constitutive replication (H9IIIB) and reversible latency (U1 and ACH-2). In PBMC, the level of total viral transcripts ranged over four orders of magnitude; however, nonprocessive transcription predominated: 70% of PBMC samples had a ratio of processive to total transcripts of <0.3 and none of the samples had 100% processivity. The cell line studies revealed that, even in activated H9IIIB cells, nonprocessive transcription dominates and that latently infected cells can have different transcriptional responses to activation. This is the first study that enumerates degrees of transcriptional processivity in the circulating mononuclear cell compartment and the results suggest that limitation of Tat function may be a common phenotype throughout the course of the disease.
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Affiliation(s)
- M Adams
- Center for Biomedical Laboratory Sciences, San Francisco State University, 1600 Holloway Avenue, San Francisco, California 94132, USA
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131
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Gorry PR, Howard JL, Churchill MJ, Anderson JL, Cunningham A, Adrian D, McPhee DA, Purcell DF. Diminished production of human immunodeficiency virus type 1 in astrocytes results from inefficient translation of gag, env, and nef mRNAs despite efficient expression of Tat and Rev. J Virol 1999; 73:352-61. [PMID: 9847339 PMCID: PMC103840 DOI: 10.1128/jvi.73.1.352-361.1999] [Citation(s) in RCA: 87] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Astrocytes infected with human immunodeficiency virus type 1 (HIV-1) produce only minimal quantities of virus. The molecular events that limit acute-phase HIV-1 infection of astrocytes were examined after inducing acute-phase replication by transfection with the pNL4-3 proviral plasmid. The levels of HIV-1 mRNA were similarly high in both astrocytes and HeLa cells, but astrocytes produced approximately 50-fold less supernatant p24 than HeLa cells. We found that diminished HIV-1 production in astrocytes resulted from inefficient translation of gag, env, and nef mRNAs that were efficiently transported to the cytoplasm. Tat- or Rev-dependent reporter constructs showed no defect in Tat or Rev function in astrocytes compared with HeLa cells. HIV-1 mRNAs were correctly spliced, but only Rev and Tat proteins were efficiently translated from their native mRNAs. Pulse-chase labelling and immunoblot experiments revealed no defect in protein processing, but levels of Gag, Env, or Nef protein expressed were dramatically reduced in astrocytes compared to HeLa cells. These results demonstrate that inefficient translation of HIV-1 structural proteins underlies the restricted infection of astrocytes. The efficient expression of functional Tat and Rev by astrocytes may contribute to HIV-1 neuropathogenesis.
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MESH Headings
- 5' Untranslated Regions
- Astrocytes/virology
- Gene Products, env/biosynthesis
- Gene Products, gag/biosynthesis
- Gene Products, nef/biosynthesis
- Gene Products, rev/biosynthesis
- Gene Products, tat/biosynthesis
- HIV Core Protein p24/biosynthesis
- HIV-1/physiology
- Humans
- Protein Biosynthesis
- RNA, Messenger/analysis
- Tumor Cells, Cultured
- nef Gene Products, Human Immunodeficiency Virus
- rev Gene Products, Human Immunodeficiency Virus
- tat Gene Products, Human Immunodeficiency Virus
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132
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Rabbi MF, Finnegan A, Al-Harthi L, Song S, Roebuck KA. Interleukin-10 enhances tumor necrosis factor-alpha activation of HIV-1 transcription in latently infected T cells. JOURNAL OF ACQUIRED IMMUNE DEFICIENCY SYNDROMES AND HUMAN RETROVIROLOGY : OFFICIAL PUBLICATION OF THE INTERNATIONAL RETROVIROLOGY ASSOCIATION 1998; 19:321-31. [PMID: 9833740 DOI: 10.1097/00042560-199812010-00002] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Interleukin-10 (IL-10) is elevated in HIV-1-infected individuals and has been implicated in disease progression. We previously reported that IL-10 cooperates with tumor necrosis factor-alpha (TNF-alpha) to activate HIV-1 expression synergistically in acutely infected monocyte-derived macrophages and the chronically infected U1 promonocytic cell line. To determine whether IL-10 also cooperates with TNF-alpha to activate latent HIV-I expression in lymphocytes, we examined the effects of IL-10 on proviral expression in the chronically infected T-cell line, ACH-2. Although IL-10 inhibited HIV-1 expression acting alone, in combination with suboptimal concentrations of TNF-alpha, IL-10 increased HIV-1 steady-state mRNA expression and p24 core antigen production in ACH-2 cells. Interestingly, IL-10 concentrations that synergistically induced virus also maximally stimulated endogenous TNF-alpha expression, suggesting that cell-derived TNF-alpha may contribute to cytokine synergy. Transfection studies in ACH-2 cells indicated that IL-10 combined with TNF-alpha to activate the HIV-1 long terminal repeat (LTR). IL-10 also cooperated with TNF-alpha to activate HIV-1 LTR in 1G5 cells, a Jurkat T-cell line stably transfected with an LTR-dependent luciferase reporter gene. Pyrrolidine dithiocarbamate, a potent transcriptional inhibitor of the viral LTR, abrogated the cytokine responses in both U1 and ACH-2 cells, suggesting a common TNF-alpha-mediated transcriptional mechanism in these cell types despite their different modes of provirus latency. Taken collectively, these data suggest that IL-10 enhances suboptimal TNF-alpha activation of HIV-1 transcription in chronically infected T-cells at least in part through induction of endogenous TNF-alpha expression.
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Affiliation(s)
- M F Rabbi
- Department of Immunology/Microbiology, Rush Presbyterian St. Luke's Medical School Chicago, Illinois, USA
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133
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Marzio G, Tyagi M, Gutierrez MI, Giacca M. HIV-1 tat transactivator recruits p300 and CREB-binding protein histone acetyltransferases to the viral promoter. Proc Natl Acad Sci U S A 1998; 95:13519-24. [PMID: 9811832 PMCID: PMC24851 DOI: 10.1073/pnas.95.23.13519] [Citation(s) in RCA: 232] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In cells infected with HIV type 1 (HIV-1), the integrated viral promoter is present in a chromatin-bound conformation and is transcriptionally silent in the absence of stimulation. The HIV-1 Tat protein binds to a stem-loop structure at the 5' end of viral mRNA and relieves this inhibition by inducing a remodeling of the nucleosome arrangement downstream of the transcription-initiation site. Here we show that Tat performs this activity by recruiting to the viral long terminal repeat (LTR) the transcriptional coactivator p300 and the closely related CREB-binding protein (CBP), having histone acetyltransferase (HAT) activity. Tat associates with HAT activity in human nuclear extracts and binds to p300 and CBP both in vitro and in vivo. Integrity of the basic domain of Tat is essential for this interaction. By a quantitative chromatin immunoprecipitation assay we show that the delivery of recombinant Tat induces the association of p300 and CBP with the chromosomally integrated LTR promoter. Expression of human p300 in both human and rodent cells increases the levels of Tat transactivation of the integrated LTR. These results reinforce the evidence that p300 and CBP have a pivotal function at both cellular and viral promoters and demonstrate that they also can be recruited by an RNA-targeted activator. Additionally, these findings have important implications for the understanding of the mechanisms of HIV-1 latency and reactivation.
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Affiliation(s)
- G Marzio
- Molecular Medicine Laboratory, International Centre for Genetic Engineering and Biotechnology (ICGEB), Padriciano 99, 34012 Trieste, Italy
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134
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Emiliani S, Fischle W, Ott M, Van Lint C, Amella CA, Verdin E. Mutations in the tat gene are responsible for human immunodeficiency virus type 1 postintegration latency in the U1 cell line. J Virol 1998; 72:1666-70. [PMID: 9445075 PMCID: PMC124653 DOI: 10.1128/jvi.72.2.1666-1670.1998] [Citation(s) in RCA: 158] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Previous reports have demonstrated that the U1 cell line, a model for postintegration latency, is defective at the level of Tat function and can be rescued by exogenously provided Tat protein. Sequence analysis of tat cDNAs from the U1 cell line identified two distinct forms of Tat, in agreement with the fact that this cell line contains two integrated human immunodeficiency (HIV) proviruses. One Tat cDNA lacked an ATG initiation codon, while the other contained an H-to-L mutation at amino acid 13 (H13-->L). Both tat cDNAs were defective in terms of transcriptional activation of long terminal repeat-luciferase reporter gene in transient-transfection experiments. Introduction of the H13-->L mutation in a wild-type tat background caused a severe reduction in transcriptional activation. Introduction of the same mutation in an infectious HIV molecular clone caused a severely defective phenotype which could be rescued when the HIV proviral DNA was transfected in a Jurkat cell line stably expressing the Tat protein (Jurkat-Tat) or in Jurkat cells treated with tumor necrosis factor alpha. Infectious virus stocks generated in Jurkat-Tat cells were used to infect Jurkat cells and exhibited severely impaired growth which could also be rescued by infecting Jurkat-Tat cells. These observations define tat mutations as a mechanism for HIV postintegration latency.
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Affiliation(s)
- S Emiliani
- The Picower Institute for Medical Research, Manhasset, New York 11030, USA
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135
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Abstract
Regulation of transcription is a key feature of the HIV-1 life cycle. In recent years, various sequence elements and transcription factors have been shown to participate in HIV-1 transcription control. New evidence, however, has shown that chromatin organization plays a key role in the establishment of a transcriptionally regulated HIV-1 LTR. The present review discusses recent data obtained on reconstituted and genomic HIV-1 chromatin templates.
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Affiliation(s)
- J Mirkovitch
- Swiss Institute for Experimental Cancer Research (ISREC), Epalinges, Switzerland.
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