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Shun MC, Raghavendra NK, Vandegraaff N, Daigle JE, Hughes S, Kellam P, Cherepanov P, Engelman A. LEDGF/p75 functions downstream from preintegration complex formation to effect gene-specific HIV-1 integration. Genes Dev 2007; 21:1767-78. [PMID: 17639082 PMCID: PMC1920171 DOI: 10.1101/gad.1565107] [Citation(s) in RCA: 367] [Impact Index Per Article: 21.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
LEDGF/p75 directly interacts with lentiviral integrase proteins and can modulate their enzymatic activities and chromosomal association. A novel genetic knockout model was established that allowed us for the first time to analyze HIV-1 integration in the absence of LEDGF/p75 protein. Supporting a crucial role for the cofactor in viral replication, HIV-1 vector integration and reporter gene expression were significantly reduced in LEDGF-null cells. Yet, integrase processed the viral cDNA termini normally and maintained its local target DNA sequence preference during integration. Preintegration complexes extracted from knockout cells moreover supported normal levels of DNA strand transfer activity in vitro. In contrast, HIV-1 lost its strong bias toward integrating into transcription units, displaying instead increased affinity for promoter regions and CpG islands. Our results reveal LEDGF/p75 as a critical targeting factor, commandeering lentiviruses from promoter- and/or CpG island-proximal pathways that are favored by other members of Retroviridae. Akin to yeast retrotransposons, disrupting the lentiviral targeting mechanism significantly perturbs overall integration.
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Affiliation(s)
- Ming-Chieh Shun
- Department of Cancer Immunology and AIDS, Dana-Farber Cancer Institute, Division of AIDS, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Nidhanapati K. Raghavendra
- Department of Cancer Immunology and AIDS, Dana-Farber Cancer Institute, Division of AIDS, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Nick Vandegraaff
- Department of Cancer Immunology and AIDS, Dana-Farber Cancer Institute, Division of AIDS, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Janet E. Daigle
- Department of Cancer Immunology and AIDS, Dana-Farber Cancer Institute, Division of AIDS, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Siobhan Hughes
- Division of Medicine, Imperial College London, St. Mary’s Campus, London W2 1PG, United Kingdom
| | - Paul Kellam
- Department of Infection, University College London, London W1T 4JF, United Kingdom
| | - Peter Cherepanov
- Division of Medicine, Imperial College London, St. Mary’s Campus, London W2 1PG, United Kingdom
- E-MAIL ; FAX 44-20-7594-3906
| | - Alan Engelman
- Department of Cancer Immunology and AIDS, Dana-Farber Cancer Institute, Division of AIDS, Harvard Medical School, Boston, Massachusetts 02115, USA
- Corresponding authors.E-MAIL
; FAX (617) 632-3113
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302
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Mousnier A, Kubat N, Massias-Simon A, Ségéral E, Rain JC, Benarous R, Emiliani S, Dargemont C. von Hippel Lindau binding protein 1-mediated degradation of integrase affects HIV-1 gene expression at a postintegration step. Proc Natl Acad Sci U S A 2007; 104:13615-20. [PMID: 17698809 PMCID: PMC1959430 DOI: 10.1073/pnas.0705162104] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
HIV-1 integrase, the viral enzyme responsible for provirus integration into the host genome, can be actively degraded by the ubiquitin-proteasome pathway. Here, we identify von Hippel-Lindau binding protein 1(VBP1), a subunit of the prefoldin chaperone, as an integrase cellular binding protein that bridges interaction between integrase and the cullin2 (Cul2)-based von Hippel-Lindau (VHL) ubiquitin ligase. We demonstrate that VBP1 and Cul2/VHL are required for proper HIV-1 expression at a step between integrase-dependent proviral integration into the host genome and transcription of viral genes. Using both an siRNA approach and Cul2/VHL mutant cells, we show that VBP1 and the Cul2/VHL ligase cooperate in the efficient polyubiquitylation of integrase and its subsequent proteasome-mediated degradation. Results presented here support a role for integrase degradation by the prefoldin-VHL-proteasome pathway in the integration-transcription transition of the viral replication cycle.
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Affiliation(s)
- Aurélie Mousnier
- *Institut Jacques Monod, Centre National de la Recherche Scientifique, Universités Paris 6 et 7, F-75251 Paris, France; and
| | - Nicole Kubat
- Institut Cochin, Université Paris Descartes, Centre National de la Recherche Scientifique, Unite Mixte de Recherche 8104
- Institut National de la Santé et de la Recherche Médicale, U567, and
| | - Aurélie Massias-Simon
- *Institut Jacques Monod, Centre National de la Recherche Scientifique, Universités Paris 6 et 7, F-75251 Paris, France; and
| | - Emmanuel Ségéral
- Institut Cochin, Université Paris Descartes, Centre National de la Recherche Scientifique, Unite Mixte de Recherche 8104
- Institut National de la Santé et de la Recherche Médicale, U567, and
| | | | - Richard Benarous
- Institut Cochin, Université Paris Descartes, Centre National de la Recherche Scientifique, Unite Mixte de Recherche 8104
- Institut National de la Santé et de la Recherche Médicale, U567, and
| | - Stéphane Emiliani
- Institut Cochin, Université Paris Descartes, Centre National de la Recherche Scientifique, Unite Mixte de Recherche 8104
- Institut National de la Santé et de la Recherche Médicale, U567, and
- To whom correspondence may be addressed at:
Département des Maladies Infectieuses, Institut Cochin, 27 Rue du Faubourg Saint Jacques, Batiment Gustave Roussy, F-75014 Paris, France. E-mail:
| | - Catherine Dargemont
- *Institut Jacques Monod, Centre National de la Recherche Scientifique, Universités Paris 6 et 7, F-75251 Paris, France; and
- To whom correspondence may be addressed at:
Institut Jacques Monod, UMR7592 CNRS, Universités Paris 6 et 7, 2 Place Jussieu, Tour 43, F-75251 Paris Cedex 05, France. E-mail:
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303
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Bartholomeeusen K, De Rijck J, Busschots K, Desender L, Gijsbers R, Emiliani S, Benarous R, Debyser Z, Christ F. Differential interaction of HIV-1 integrase and JPO2 with the C terminus of LEDGF/p75. J Mol Biol 2007; 372:407-21. [PMID: 17669426 DOI: 10.1016/j.jmb.2007.06.090] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2007] [Revised: 06/27/2007] [Accepted: 06/29/2007] [Indexed: 11/28/2022]
Abstract
The transcriptional co-activator lens epithelium-derived growth factor (LEDGF) has been shown to protect cells against environmental stress. The protein has been implicated in auto-immunity and cancer, and is present in cells as the p52 or p75 splice variant. Recently, LEDGF/p75, but not p52, was identified as the prominent interaction partner of human immunodeficiency virus type 1 (HIV-1) integrase. This interaction of HIV-1 integrase with the C-terminal integrase-binding domain of LEDGF/p75 is crucial for HIV-1 replication. To gain insight into the cell biology of LEDGF/p75, we were interested in identifying cellular binding partners of its C-terminal domain. By yeast-two-hybrid screening with a CEMC7 cDNA-library, we were able to identify JPO2 as a binding partner of the C-terminal part of LEDGF/p75. The specific interaction between JPO2 and LEDGF/p75 was verified by pull-down, AlphaScreen, and co-immunoprecipitation. Competition assays using recombinant proteins show a mutually exclusive binding of either JPO2 or HIV-1 integrase to LEDGF/p75. However, differing mechanisms of binding were suggested by continuing interaction of JPO2 with some LEDGF/p75 mutants (I365A, D366A, F406A) that are totally defective for interaction with HIV-1 integrase. This finding is of significance for the development of specific inhibitors targeting only the interaction between LEDGF/p75 and HIV-1 integrase, without disturbing interaction with other cellular factors. Over-expression of JPO2 resulted in a modest but reproducible inhibition of HIV-1 replication, consistent with competition between integrase and JPO2 for binding to LEDGF/p75. Furthermore, JPO2 over-expression activated transcription from the HIV-1 LTR.
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304
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Hombrouck A, De Rijck J, Hendrix J, Vandekerckhove L, Voet A, Maeyer MD, Witvrouw M, Engelborghs Y, Christ F, Gijsbers R, Debyser Z. Virus evolution reveals an exclusive role for LEDGF/p75 in chromosomal tethering of HIV. PLoS Pathog 2007; 3:e47. [PMID: 17397262 PMCID: PMC1839165 DOI: 10.1371/journal.ppat.0030047] [Citation(s) in RCA: 99] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2006] [Accepted: 02/14/2007] [Indexed: 01/19/2023] Open
Abstract
Retroviruses by definition insert their viral genome into the host cell chromosome. Although the key player of retroviral integration is viral integrase, a role for cellular cofactors has been proposed. Lentiviral integrases use the cellular protein LEDGF/p75 to tether the preintegration complex to the chromosome, although the existence of alternative host proteins substituting for the function of LEDGF/p75 in integration has been proposed. Truncation mutants of LEDGF/p75 lacking the chromosome attachment site strongly inhibit HIV replication by competition for the interaction with integrase. In an attempt to select HIV strains that can overcome the inhibition, we now have used T-cell lines that stably express a C-terminal fragment of LEDGF/p75. Despite resistance development, the affinity of integrase for LEDGF/p75 is reduced and replication kinetics in human primary T cells is impaired. Detection of the integrase mutations A128T and E170G at key positions in the LEDGF/p75–integrase interface provides in vivo evidence for previously reported crystallographic data. Moreover, the complementary inhibition by LEDGF/p75 knockdown and mutagenesis at the integrase–LEDGF/p75 interface points to the incapability of HIV to circumvent LEDGF/p75 function during proviral integration. Altogether, the data provide a striking example of the power of viral molecular evolution. The results underline the importance of the LEDGF/p75 HIV-1 interplay as target for innovative antiviral therapy. Moreover, the role of LEDGF/p75 in targeting integration will stimulate research on strategies to direct gene therapy vectors into safe landing sites. Viruses have a limited genome and therefore exploit the cellular machinery of infected host cells to complete the replication cycle. Today there is a growing interest to unravel these virus–host interactions. Lentiviral integrases use the cellular protein LEDGF/p75 to tether the preintegration complex to the chromosome, although the existence of alternative host proteins substituting for the function of LEDGF/p75 has been proposed. Here, we used virus evolution to investigate the role and importance of LEDGF/p75 in HIV integration and replication. We selected a virus that is resistant against overexpression of the integrase binding domain of LEDGF/p75. This virus displays a reduced affinity for its own cofactor but still depends on the cofactor for replication. We demonstrate the unique and essential role of LEDGF/p75 in HIV replication and support the LEDGF/p75 HIV-1 interplay as target for innovative antiviral therapy. Moreover, elucidation of the role of LEDGF/p75 in targeting integration will stimulate research on strategies to direct gene therapy vectors into safe landing sites.
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Affiliation(s)
- Anneleen Hombrouck
- The Laboratory for Molecular Virology and Gene Therapy, KULeuven and IRC KULAK, Leuven, Flanders, Belgium
| | - Jan De Rijck
- The Laboratory for Molecular Virology and Gene Therapy, KULeuven and IRC KULAK, Leuven, Flanders, Belgium
| | - Jelle Hendrix
- The Laboratory for Biomolecular Dynamics, KULeuven, Leuven, Flanders, Belgium
| | - Linos Vandekerckhove
- The Laboratory for Molecular Virology and Gene Therapy, KULeuven and IRC KULAK, Leuven, Flanders, Belgium
| | - Arnout Voet
- The Laboratory for Biomolecular Modelling, KULeuven, Leuven, Flanders, Belgium
| | - Marc De Maeyer
- The Laboratory for Biomolecular Modelling, KULeuven, Leuven, Flanders, Belgium
| | - Myriam Witvrouw
- The Laboratory for Molecular Virology and Gene Therapy, KULeuven and IRC KULAK, Leuven, Flanders, Belgium
| | - Yves Engelborghs
- The Laboratory for Biomolecular Dynamics, KULeuven, Leuven, Flanders, Belgium
| | - Frauke Christ
- The Laboratory for Molecular Virology and Gene Therapy, KULeuven and IRC KULAK, Leuven, Flanders, Belgium
| | - Rik Gijsbers
- The Laboratory for Molecular Virology and Gene Therapy, KULeuven and IRC KULAK, Leuven, Flanders, Belgium
| | - Zeger Debyser
- The Laboratory for Molecular Virology and Gene Therapy, KULeuven and IRC KULAK, Leuven, Flanders, Belgium
- * To whom correspondence should be addressed. E-mail:
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305
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Hayouka Z, Rosenbluh J, Levin A, Loya S, Lebendiker M, Veprintsev D, Kotler M, Hizi A, Loyter A, Friedler A. Inhibiting HIV-1 integrase by shifting its oligomerization equilibrium. Proc Natl Acad Sci U S A 2007; 104:8316-21. [PMID: 17488811 PMCID: PMC1895947 DOI: 10.1073/pnas.0700781104] [Citation(s) in RCA: 153] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2007] [Indexed: 11/18/2022] Open
Abstract
Proteins are involved in various equilibria that play a major role in their activity or regulation. The design of molecules that shift such equilibria is of great therapeutic potential. This fact was demonstrated in the cases of allosteric inhibitors, which shift the equilibrium between active and inactive (R and T) states, and chemical chaperones, which shift folding equilibrium of proteins. Here, we expand these concepts and propose the shifting of oligomerization equilibrium of proteins as a general methodology for drug design. We present a strategy for inhibiting proteins by "shiftides": ligands that specifically bind to an inactive oligomeric state of a disease-related protein and modulate its activity by shifting the oligomerization equilibrium of the protein toward it. We demonstrate the feasibility of our approach for the inhibition of the HIV-1 integrase (IN) protein by using peptides derived from its cellular-binding protein, LEDGF/p75, which specifically inhibit IN activity by a noncompetitive mechanism. The peptides inhibit the DNA-binding of IN by shifting the IN oligomerization equilibrium from the active dimer toward the inactive tetramer, which is unable to catalyze the first integration step of 3' end processing. The LEDGF/p75-derived peptides inhibit the enzymatic activity of IN in vitro and consequently block HIV-1 replication in cells because of the lack of integration. These peptides are promising anti-HIV lead compounds that modulate oligomerization of IN via a previously uncharacterized mechanism, which bears advantages over the conventional interface dimerization inhibitors.
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Affiliation(s)
| | | | - Aviad Levin
- Department of Biological Chemistry
- Department of Pathology, Hebrew University–Hadassah Medical School, Jerusalem 91120, Israel
| | - Shoshana Loya
- Department of Cell and Developmental Biology, The Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel; and
| | - Mario Lebendiker
- Protein Purification Unit, Hebrew University of Jerusalem, Givat Ram, Jerusalem 91904, Israel
| | - Dmitry Veprintsev
- Centre for Protein Engineering, Medical Research Council Centre, Hills Road, Cambridge CB2 2QH, United Kingdom
| | - Moshe Kotler
- Department of Pathology, Hebrew University–Hadassah Medical School, Jerusalem 91120, Israel
| | - Amnon Hizi
- Department of Cell and Developmental Biology, The Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel; and
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306
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Lataillade M, Chiarella J, Kozal MJ. Natural Polymorphism of the HIV-1 Integrase Gene and Mutations associated with Integrase Inhibitor Resistance. Antivir Ther 2007. [DOI: 10.1177/135965350701200411] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Background Two inhibitors of the HIV-1 integrase enzyme (INIs) are in late stage clinical development. To date, approximately 42 mutations within the HIV-1 integrase (IN) gene have been associated with INI drug resistance. Naturally occurring IN gene polymorphisms may have important implications for INI development. In this study, we evaluated clinical HIV-1 strains from INI-naive patients to determine the prevalence of IN gene polymorphisms, and the frequency of naturally occurring amino acid (aa) substitutions at positions associated with INI resistance and at sites crucial for LEDGF/p75 binding and HIV-1 integration. Methods The IN gene from 67 INI-naive, HIV-1 clade B-infected patients were sequenced using standard population-based DNA sequencing methods. In addition, 176 unique full-length HIV-1 clade B IN gene sequences from INI-naive patients obtained from the HIV Los Alamos database were analysed. Results Analysis of 243 IN genes from HIV-1 clade B, INI-naive clinical strains revealed that 64% of the aa positions were polymorphic. Of the 42 aa substitutions currently associated with INI resistance, 21 occurred as natural polymorphisms: V72I, L74I, T97A, T112I, A128T, E138K, Q148H, V151I, S153Y/A, M154I, N155H, K156N, E157Q, G163R, V165I, V201I, I203M, T206S, S230N and R263K. IN aa positions crucial to LEDGF/P75 binding and HIV-1 integration were well conserved. Conclusion Major INI mutations within the catalytic domain and extended active sites associated with high level resistance to the compounds in late stage development, especially strand transfer inhibitors (STIs), were infrequent in our study, which may help explain the excellent virological responses demonstrated in clinical trials.
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Affiliation(s)
| | | | - Michael J Kozal
- Yale University School of Medicine, New Haven, CT, USA
- VA Connecticut Healthcare System, New Haven, CT, USA
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307
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Berthoux L, Sebastian S, Muesing MA, Luban J. The role of lysine 186 in HIV-1 integrase multimerization. Virology 2007; 364:227-36. [PMID: 17397894 PMCID: PMC2149894 DOI: 10.1016/j.virol.2007.02.029] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2007] [Revised: 01/30/2007] [Accepted: 02/13/2007] [Indexed: 11/21/2022]
Abstract
HIV-1 integrase (IN) catalyzes biochemical reactions required for viral cDNA insertion into host cell chromosomal DNA, an essential step in the HIV-1 replication cycle. In one of these reactions, the two ends of the linear viral cDNA are believed to be simultaneously ligated to chromosomal DNA by a tetrameric form of IN. The structure of the full-length IN tetramer is not known but a model consisting of the N-terminal domain and the catalytic core revealed basic residues 186 to 188 at the interface between the two IN dimers. We found that alteration of these residues, in particular changing IN lysine residue 186 to glutamate (K186Q), impairs IN oligomerization in the yeast two-hybrid system and decreases oligomeric forms of IN within virions. When expressed independently of other viral proteins in human cells, IN-K186Q did not concentrate in the nucleus as did wild-type IN. Co-expression of wild-type IN restored the multimerization defects of IN-K186Q, in both the two-hybrid system and in virions, and also rescued the nuclear targeting defects. Virions bearing IN-K186Q were not infectious in a single cycle of replication but when mixed virions containing two different IN mutants were produced, IN-K186Q was capable of complementing the catalytically inactive mutant IN-D116A. Our biochemical and functional data support the crystallographic model in which IN residue K186 lies at the interface between IN dimers and suggest that tetramerization is important, not only for concerted integration, but also for IN nuclear targeting.
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Affiliation(s)
| | | | - Mark A. Muesing
- Aaron Diamond AIDS Research Center, The Rockefeller University, New York
| | - Jeremy Luban
- Department of Microbiology, Columbia University, New York
- Department of Medicine, Columbia University, New York
- Institute for Research in Biomedicine, Bellinzona, Switzerland
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308
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Savarino A. In-Silico docking of HIV-1 integrase inhibitors reveals a novel drug type acting on an enzyme/DNA reaction intermediate. Retrovirology 2007; 4:21. [PMID: 17374162 PMCID: PMC1847836 DOI: 10.1186/1742-4690-4-21] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2007] [Accepted: 03/20/2007] [Indexed: 02/06/2023] Open
Abstract
Background HIV-1 integrase (IN) is an emerging drug target, as IN strand transfer inhibitors (INSTIs) are proving potent antiretroviral agents in clinical trials. One credible theory sees INSTIs as docking at the cellular (acceptor) DNA-binding site after IN forms a transitional complex with viral (donor) DNA. However, mapping of the DNA and INSTI binding sites within the IN catalytic core domain (CCD) has been uncertain. Methods Structural superimpositions were conducted using the SWISS PDB and Cn3D free software. Docking simulations of INSTIs were run by a widely validated genetic algorithm (GOLD). Results Structural superimpositions suggested that a two-metal model for HIV-1 IN CCD in complex with small molecule, 1-(5-chloroindol-3-yl)-3-(tetrazoyl)-1,3-propandione-ene (5CITEP) could be used as a surrogate for an IN/viral DNA complex, because it allowed replication of contacts documented biochemically in viral DNA/IN complexes or displayed by a crystal structure of the IN-related enzyme Tn5 transposase in complex with transposable DNA. Docking simulations showed that the fitness of different compounds for the catalytic cavity of the IN/5CITEP complex significantly (P < 0.01) correlated with their 50% inhibitory concentrations (IC50s) in strand transfer assays in vitro. The amino acids involved in inhibitor binding matched those involved in drug resistance. Both metal binding and occupation of the putative viral DNA binding site by 5CITEP appeared to be important for optimal drug/ligand interactions. The docking site of INSTIs appeared to overlap with a putative acceptor DNA binding region adjacent to but distinct from the putative donor DNA binding site, and homologous to the nucleic acid binding site of RNAse H. Of note, some INSTIs such as 4,5-dihydroxypyrimidine carboxamides/N-Alkyl-5-hydroxypyrimidinone carboxamides, a highly promising drug class including raltegravir/MK-0518 (now in clinical trials), displayed interactions with IN reminiscent of those displayed by fungal molecules from Fusarium sp., shown in the 1990s to inhibit HIV-1 integration. Conclusion The 3D model presented here supports the idea that INSTIs dock at the putative acceptor DNA-binding site in a IN/viral DNA complex. This mechanism of enzyme inhibition, likely to be exploited by some natural products, might disclose future strategies for inhibition of nucleic acid-manipulating enzymes.
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Affiliation(s)
- Andrea Savarino
- Department of Infectious, Parasitic and Immune-mediated Diseases, Istituto Superiore di Sanità, Rome, Italy.
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309
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Yu F, Jones GS, Hung M, Wagner AH, MacArthur HL, Liu X, Leavitt S, McDermott MJ, Tsiang M. HIV-1 integrase preassembled on donor DNA is refractory to activity stimulation by LEDGF/p75. Biochemistry 2007; 46:2899-908. [PMID: 17298035 DOI: 10.1021/bi602387u] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
LEDGF/p75 is known to enhance the integrase strand transfer activity in vitro, but the underlying mechanism is unclear. Using an integrase assay with a chemiluminescent readout adapted to a 96-well plate format, the effect of LEDGF/p75 on both the 3'-processing and strand transfer steps was analyzed. Integrase inhibitors of the strand transfer reaction remained active in the presence of LEDGF/p75, but displayed 3- to 7-fold higher IC50 values. Our analyses indicate that, in the presence of 150 nM LEDGF/p75, active integrase/donor DNA complexes were increased by 5.3-fold during the 3'-processing step. In addition, these integrase/donor DNA complexes showed a 4.5-fold greater affinity for the target DNA during the subsequent strand transfer step. We also observed a 3.7-fold increase in the rate constant of catalysis of the strand transfer step when 150 nM LEDGF/p75 was present during the 3'-processing step. In contrast, when LEDGF/p75 was added at the beginning of the strand transfer step, no increase in either the concentration of active integrase/donor DNA complex or its rate constant of strand transfer catalysis was observed. This observation suggested that the integrase/donor DNA formed in the absence of LEDGF/p75 became refractory to the stimulatory effect of LEDGF/p75. Instead, this LEDGF/p75 added at the start of the strand transfer step was able to promote the formation of a new cohort of active integrase/donor DNA complexes which became functional with a delay of 45 min after LEDGF/p75 addition. We propose a model whereby LEDGF/p75 can only bind integrase before the latter binds donor DNA whereas donor DNA can engage either free or LEDGF/p75-bound integrase.
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Affiliation(s)
- Fang Yu
- Gilead Sciences, 333 Lakeside Drive, Foster City, California 94404, USA
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310
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Avila-Ríos S, Reyes-Terán G, Espinosa E. Cornering HIV: taking advantage of interactions between selective pressures. Med Hypotheses 2007; 69:422-31. [PMID: 17280799 DOI: 10.1016/j.mehy.2006.12.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2006] [Accepted: 12/03/2006] [Indexed: 10/23/2022]
Abstract
Adaptive immune responses, cellular restrictive factors and antiretroviral drugs, target multiple regions in the Human Immunodeficiency Virus (HIV) proteome, imposing diverse pressures to viral adaptation. However, the virus is remarkably able to escape from these pressures as mutations are selected. In many cases these mutants have diminished viral fitness. We propose that the concerted action of strategically placed agents and pressures in a host can limit HIV variation capacity while inhibiting its replication. These mechanisms would corner HIV by selecting conflicting adaptive mutations, each having a disadvantage in face of another selective pressure. This would keep the virus unable to efficiently escape the suppressive effects of selective pressures. Cornering between antiretroviral drugs and cytotoxic T lymphocytes may explain recent observations, and can be predicted and used in viral control strategies. This idea can be extended to numerous other identified sites in the viral genome that confer selective pressures. We describe these other sites and how they could be induced to interact in prophylactic or therapeutic cornering strategies, as well as their experimental verifications. Cornering would control HIV infection better than current strategies, focused on few, albeit important, sites in the HIV genome.
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Affiliation(s)
- S Avila-Ríos
- Center for Infectious Diseases Research, National Institute of Respiratory Diseases, Calzada de Tlalpan 4502, CP 14080 Mexico City, Mexico
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311
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Pandey KK, Sinha S, Grandgenett DP. Transcriptional coactivator LEDGF/p75 modulates human immunodeficiency virus type 1 integrase-mediated concerted integration. J Virol 2007; 81:3969-79. [PMID: 17267486 PMCID: PMC1866116 DOI: 10.1128/jvi.02322-06] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Human transcriptional coactivator p75/lens epithelium-derived growth factor (LEDGF) binds human immunodeficiency virus type 1 (HIV-1) integrase (IN). We studied the effects of LEDGF on the assembly and activity of HIV-1 synaptic complexes, which, upon association with a target, mediate concerted integration of viral DNA substrates in vitro. We found that while augmenting single-ended viral DNA integration into target DNA, the host factor was able to either stimulate or abrogate concerted integration in a concentration-dependent manner. LEDGF modestly stimulated (two- to threefold) concerted integration at low molar ratios to IN (<1). The modest stimulation was independent of solution conditions and several different viral DNA substrates. In solution, concerted integration was inhibited if the molar ratios of LEDGF to IN were >1, apparently due to the disruption of IN-IN interactions essential for the formation of active synaptic complexes prior to their association with a circular target. The isolated IN binding domain of LEDGF was sufficient to stimulate and inhibit concerted integration, as observed with full-length protein, albeit at lower efficiencies. Our data show that LEDGF differentially affects IN-DNA complexes mediating single-ended viral DNA integration and synaptic complexes mediating concerted integration. Synaptic complexes associated with target, termed strand transfer complexes, are resistant to disruption by high concentrations of LEDGF. The results suggest that LEDGF may influence HIV-1 integration in vivo.
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Affiliation(s)
- Krishan K Pandey
- Institute for Molecular Virology, 3681 Park Avenue, Saint Louis University Health Sciences Center, St. Louis, MO 63110, USA.
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312
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Cherepanov P. LEDGF/p75 interacts with divergent lentiviral integrases and modulates their enzymatic activity in vitro. Nucleic Acids Res 2006; 35:113-24. [PMID: 17158150 PMCID: PMC1802576 DOI: 10.1093/nar/gkl885] [Citation(s) in RCA: 146] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Transcriptional co-activator LEDGF/p75 is the major cellular interactor of HIV-1 integrase (IN), critical to efficient viral replication. In this work, a series of INs from the Betaretrovirus, Gammaretrovirus, Deltaretrovirus, Spumavirus and Lentivirus retroviral genera were tested for interaction with the host factor. None of the non-lentiviral INs possessed detectable affinity for LEDGF in either pull-down or yeast two-hybrid assays. In contrast, all lentiviral INs examined, including those from bovine immunodeficiency virus (BIV), maedi-visna virus (MVV) and equine infectious anemia virus (EIAV) readily interacted with LEDGF. Mutation of Asp-366 to Asn in LEDGF ablated the interaction, suggesting a common mechanism of the host factor recognition by the INs. LEDGF potently stimulated strand transfer activity of divergent lentiviral INs in vitro. Unprecedentedly, in the presence of the host factor, EIAV IN almost exclusively catalyzed concerted integration, whereas HIV-1 IN promoted predominantly half-site integration, and BIV IN was equally active in both types of strand transfer. Concerted BIV and EIAV integration resulted in 5 bp duplications of the target DNA sequences. These results confirm that the interaction with LEDGF is conserved within and limited to Lentivirus and strongly argue that the host factor is intimately involved in the catalysis of lentiviral DNA integration.
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Affiliation(s)
- Peter Cherepanov
- Section of Infectious Diseases, Division of Medicine, Imperial College London, St Mary's Campus, Norfolk Place, W2 1PG, London, UK.
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313
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Busschots K, Voet A, De Maeyer M, Rain JC, Emiliani S, Benarous R, Desender L, Debyser Z, Christ F. Identification of the LEDGF/p75 binding site in HIV-1 integrase. J Mol Biol 2006; 365:1480-92. [PMID: 17137594 DOI: 10.1016/j.jmb.2006.10.094] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2006] [Revised: 10/27/2006] [Accepted: 10/30/2006] [Indexed: 10/23/2022]
Abstract
Lens epithelium-derived growth factor (LEDGF)/p75 is an important cellular co-factor for human immunodeficiency virus (HIV) replication. We originally identified LEDGF/p75 as a binding partner of integrase (IN) in human cells. The interaction has been mapped to the integrase-binding domain (IBD) of LEDGF/p75 located in the C-terminal part. We have subsequently shown that IN carrying the Q168A mutation remains enzymatically active but is impaired for interaction with LEDGF/p75. To map the integrase/LEDGF interface in more detail, we have now identified and characterized two regions within the enzyme involved in the interaction with LEDGF/p75. The first region centers around residues W131 and W132 while the second extends from I161 up to E170. For the different IN mutants the interaction with LEDGF/p75 and the enzymatic activities were determined. IN(W131A), IN(I161A), IN(R166A), IN(Q168A) and IN(E170A) are impaired for interaction with LEDGF/p75, but retain 3' processing and strand transfer activities. Due to impaired integration, an HIV-1 strain containing the W131A mutation in IN displays reduced replication capacity, whereas virus carrying IN(Q168A) is replication defective. Comparison of the wild-type IN-LEDGF/p75 co-crystal structure with that of the modelled structure of the IN(Q168A) and IN(W131A) mutant integrases corroborated our experimental data.
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Affiliation(s)
- Katrien Busschots
- Laboratory for Molecular Virology and Gene Therapy, Molecular Medicine, Katholieke Universiteit Leuven, Flanders, Belgium
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314
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Abstract
HIV-1 integrase, which catalyzes the joining of viral DNA to the host cell DNA, has attracted considerable attention as a target for the design and screening of novel anti-HIV drugs as it is essential for virus replication and the establishment of persistent infection. Progress in the identification of different classes of compounds that block integrase activity has been summarized recently in several excellent reviews. Here, we present a brief overview of integrase inhibition, highlighting some of the unusual properties of this protein and important considerations in searching for potential new inhibitors and their evaluation.
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Affiliation(s)
- Joseph Ramcharan
- Locus Pharmaceuticals Inc., 4 Valley Square, 512 East Township Line Road, Blue Bell, PA 19422, USA
| | - Anna Marie Skalka
- Fox Chase Cancer Center, Institute for Cancer Research, Philadelphia, PA 19111, USA
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315
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Sutherland HG, Newton K, Brownstein DG, Holmes MC, Kress C, Semple CA, Bickmore WA. Disruption of Ledgf/Psip1 results in perinatal mortality and homeotic skeletal transformations. Mol Cell Biol 2006; 26:7201-10. [PMID: 16980622 PMCID: PMC1592893 DOI: 10.1128/mcb.00459-06] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
PC4- and SF2-interacting protein 1 (Psip1)-also known as lens epithelium-derived growth factor (Ledgf)-is a chromatin-associated protein that has been implicated in transcriptional regulation, mRNA splicing, and cell survival in vitro, but its biological function in vivo is unknown. We identified an embryonic stem cell clone with disrupted Psip1 in a gene trap screen. The resulting Psip1-betageo fusion protein retains chromatin-binding activity and the PWWP and AT hook domains of the wild-type protein but is missing the highly conserved C terminus. The majority of mice homozygous for the disrupted Psip1 gene died perinatally, but some survived to adulthood and displayed a range of phenotypic abnormalities, including low fertility, an absence of epididymal fat pads, and a tendency to develop blepharitis. However, contrary to expectations, the lens epithelium was normal. The mutant mice also exhibited motor and/or behavioral defects such as hind limb clenching, reduced grip strength, and reduced locomotor activity. Finally, both Psip1(-/-) neonates and surviving adults had craniofacial and skeletal abnormalities. They had brachycephaly, small rib cages, and homeotic skeletal transformations with incomplete penetrance. The latter phenotypes suggest a role for Psip1 in the control of Hox expression and may also explain why PSIP1 (LEDGF) is found as a fusion partner with NUP98 in myeloid leukemias.
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MESH Headings
- Adaptor Proteins, Signal Transducing/deficiency
- Adaptor Proteins, Signal Transducing/genetics
- Adaptor Proteins, Signal Transducing/metabolism
- Animals
- Animals, Outbred Strains
- Behavior, Animal
- Bone and Bones/abnormalities
- Cells, Cultured
- Chromatin/metabolism
- Conserved Sequence
- Embryo, Mammalian/cytology
- Embryo, Mammalian/pathology
- Eye/cytology
- Eye/pathology
- Female
- Gene Expression Regulation, Developmental
- Gene Targeting
- Homeodomain Proteins/genetics
- Homozygote
- Humans
- Mice
- Mice, Mutant Strains
- Motor Skills Disorders/pathology
- Phenotype
- Protein Structure, Tertiary
- Survival Analysis
- Transcription Factors/deficiency
- Transcription Factors/genetics
- Transcription Factors/metabolism
- Up-Regulation/genetics
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316
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Masuda T. [Host factors that regulate the intercellular dynamics of HIV-1 genome during the early phase of infection]. Uirusu 2006; 56:41-50. [PMID: 17038811 DOI: 10.2222/jsv.56.41] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
An interplay or battle between virus and its host has been observed within a single cell. Upon an infection with retroviruses including human immunodeficiency virus type 1 (HIV-1), the viral genome is subjected to several processes that include uncoating, reverse transcription of the viral genomic RNA into a cDNA copy, transport of this cDNA into the nucleus, and integration of the cDNA into the host chromosome. Antiretroviral restriction factors such as TRIM5 alpha and APOBEC3G have been recently identified. In addition, nuclear membrane protect host chromosomal DNA against incoming viral genome. For successful retroviral infection, viral genome must overcome these cellular barriers to establish proviral state, in which viral cDNA was stably integrated into host chromosomal DNA. In this review, I would summarize the host factors that regulate the intercellular dynamics of HIV-1 genome during the early phase of infection, especially focusing on factors interacting with HIV-1 integrase and the preintegration complex.
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Affiliation(s)
- Takao Masuda
- Department of Immunotherapeutics, Graduate School of Medicine and Dentistry, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan.
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317
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Puglia J, Wang T, Smith-Snyder C, Cote M, Scher M, Pelletier JN, John S, Jonsson CB, Roth MJ. Revealing domain structure through linker-scanning analysis of the murine leukemia virus (MuLV) RNase H and MuLV and human immunodeficiency virus type 1 integrase proteins. J Virol 2006; 80:9497-510. [PMID: 16973554 PMCID: PMC1617218 DOI: 10.1128/jvi.00856-06] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2006] [Accepted: 07/07/2006] [Indexed: 11/20/2022] Open
Abstract
Linker-scanning libraries were generated within the 3' terminus of the Moloney murine leukemia virus (M-MuLV) pol gene encoding the connection-RNase H domains of reverse transcriptase (RT) as well as the structurally related M-MuLV and human immunodeficiency virus type 1 (HIV-1) integrase (IN) proteins. Mutations within the M-MuLV proviral vectors were Tn7 based and resulted in 15-bp insertions. Mutations within an HIV-1 IN bacterial expression vector were based on Tn5 and resulted in 57-bp insertions. The effects of the insertions were examined in vivo (M-MuLV) and in vitro (HIV-1). A total of 178 individual M-MuLV constructs were analyzed; 40 in-frame insertions within RT connection-RNase H, 108 in-frame insertions within IN, 13 insertions encoding stop codons within RNase H, and 17 insertions encoding stop codons within IN. For HIV-1 IN, 56 mutants were analyzed. In both M-MuLV and HIV-1 IN, regions are identified which functionally tolerate multiple-linker insertions. For MuLV, these correspond to the RT-IN proteolytic junction, the junction between the IN core and C terminus, and the C terminus of IN. For HIV-1 IN, in addition to the junction between the IN core and C terminus and the C terminus of IN, insertions between the N terminus and core domains maintained integration and disintegration activity. Of the 40 in-frame insertions within the M-MuLV RT connection-RNase H domains, only the three C-terminal insertions mapping to the RT-IN proteolytic junction were viable. These results correlate with deletion studies mapping the domain and subdomain boundaries of RT and IN. Importantly, these genetic footprints provide a means to identify nonessential regions within RT and IN for targeted gene therapy applications.
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Affiliation(s)
- Jennifer Puglia
- Department of Biochemistry, Robert Wood Johnson Medical School, University of Medicine and Dentistry of New Jersey, 675 Hoes Lane, Piscataway, NJ 08854, USA
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318
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De Rijck J, Vandekerckhove L, Gijsbers R, Hombrouck A, Hendrix J, Vercammen J, Engelborghs Y, Christ F, Debyser Z. Overexpression of the lens epithelium-derived growth factor/p75 integrase binding domain inhibits human immunodeficiency virus replication. J Virol 2006; 80:11498-509. [PMID: 16987986 PMCID: PMC1642583 DOI: 10.1128/jvi.00801-06] [Citation(s) in RCA: 134] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We initially identified lens epithelium-derived growth factor/p75 (LEDGF/p75) as a binding partner of human immunodeficiency virus type 1 (HIV-1) integrase. To investigate the role of LEDGF/p75 in HIV replication and its potential as a new antiviral target, we stably overexpressed two different fragments containing the integrase binding domain (IBD) of LEDGF/p75 fused to enhanced green fluorescent protein (eGFP). HIV-1 replication was severely inhibited by overexpression of the eGFP-IBD fusion proteins, while no inhibition was observed in cell lines overexpressing the interaction-deficient D366A mutant. Quantitative PCR pinpointed the block to the integration step, whereas nuclear import was not affected. Competition of the IBD fusion proteins with endogenous LEDGF/p75 for binding to integrase led to a potent defect in HIV-1 replication in both HeLaP4- and MT-4-derived cell lines. A previously described diketo acid-resistant HIV-1 strain remained fully susceptible to inhibition, suggesting that this strategy will also work in patients who harbor strains resistant to the current experimental integrase inhibitors. These data support LEDGF/p75 as an important cofactor for HIV replication and provide proof of concept for the LEDGF/p75-integrase interaction as a novel target for treating HIV-1 infection.
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Affiliation(s)
- Jan De Rijck
- Molecular Medicine, KU Leuven and IRC KULAK, Kapucijnenvoer 33 VCTB+5, B-3000 Leuven, Belgium
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319
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Rahman S, Lu R, Vandegraaff N, Cherepanov P, Engelman A. Structure-based mutagenesis of the integrase-LEDGF/p75 interface uncouples a strict correlation between in vitro protein binding and HIV-1 fitness. Virology 2006; 357:79-90. [PMID: 16959283 DOI: 10.1016/j.virol.2006.08.011] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2006] [Revised: 07/18/2006] [Accepted: 08/03/2006] [Indexed: 11/20/2022]
Abstract
LEDGF/p75 binding-defective IN mutant viruses were previously characterized as replication-defective, yet RNAi did not reveal an essential role for the host factor in HIV-1 replication. Correlative analyses of protein binding and viral fitness were expanded here by targeting 12 residues at the IN-LEDGF/p75 binding interface. Whereas many of the resultant viruses were defective, the majority of the INs displayed wild-type in vitro integration activities. Though an overall trend of parallel loss of LEDGF/p75 binding and HIV-1 infectivity was observed, a strict correlation was not. His-tagged IN(A128Q), derived from a phenotypically wild-type virus, failed to pull-down LEDGF/p75, but IN(A128Q) was effectively recovered in a reciprocal GST pull-down assay. Under these conditions, IN(H171A), also derived from a phenotypically wild-type virus, interacted less efficiently than a previously described interaction-defective mutant, IN(Q168A). Thus, the relative affinity of the in vitro IN-LEDGF/p75 interaction is not a universal predictor of IN mutant viral fitness.
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Affiliation(s)
- Shaila Rahman
- Department of Cancer Immunology and AIDS, Dana-Farber Cancer Institute, Boston, MA 02115, USA
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320
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Marchand C, Johnson AA, Semenova E, Pommier Y. Mechanisms and inhibition of HIV integration. DRUG DISCOVERY TODAY. DISEASE MECHANISMS 2006; 3:253-260. [PMID: 20431697 PMCID: PMC2860614 DOI: 10.1016/j.ddmec.2006.05.004] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
HIV integrase is required for viral replication and a rationale target for antiretroviral therapies. Integrase inhibitors are potentially complementary to current treatments. This review focuses on the mechanisms of HIV integration. The roles of viral and cellular co-factors during pre-integration complex (PIC) formation and integration are reviewed. The biochemical mechanisms of integration, integrase structures and approaches to inhibit integration are described.
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Affiliation(s)
- Christophe Marchand
- Laboratory of Molecular Pharmacology, Bldg. 37, Rm. 5068, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892-4255
| | - Allison A Johnson
- Laboratory of Molecular Pharmacology, Bldg. 37, Rm. 5068, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892-4255
| | - Elena Semenova
- Laboratory of Molecular Pharmacology, Bldg. 37, Rm. 5068, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892-4255
| | - Yves Pommier
- Laboratory of Molecular Pharmacology, Bldg. 37, Rm. 5068, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892-4255
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321
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Al-Mawsawi LQ, Fikkert V, Dayam R, Witvrouw M, Burke TR, Borchers CH, Neamati N. Discovery of a small-molecule HIV-1 integrase inhibitor-binding site. Proc Natl Acad Sci U S A 2006; 103:10080-5. [PMID: 16785440 PMCID: PMC1502509 DOI: 10.1073/pnas.0511254103] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Herein, we report the identification of a unique HIV-1 integrase (IN) inhibitor-binding site using photoaffinity labeling and mass spectrometric analysis. We chemically incorporated a photo-activatable benzophenone moiety into a series of coumarin-containing IN inhibitors. A representative of this series was covalently photo-crosslinked with the IN core domain and subjected to HPLC purification. Fractions were subsequently analyzed by using MALDI-MS and electrospray ionization (ESI)-MS to identify photo-crosslinked products. In this fashion, a single binding site for an inhibitor located within the tryptic peptide (128)AACWWAGIK(136) was identified. Site-directed mutagenesis followed by in vitro inhibition assays resulted in the identification of two specific amino acid residues, C130 and W132, in which substitutions resulted in a marked resistance to the IN inhibitors. Docking studies suggested a specific disruption in functional oligomeric IN complex formation. The combined approach of photo-affinity labeling/MS analysis with site-directed mutagenesis/molecular modeling is a powerful approach for elucidating inhibitor-binding sites of proteins at the atomic level. This approach is especially important for the study of proteins that are not amenable to traditional x-ray crystallography and NMR techniques. This type of structural information can help illuminate processes of inhibitor resistance and thereby facilitate the design of more potent second-generation inhibitors.
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Affiliation(s)
- Laith Q. Al-Mawsawi
- *Department of Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, CA 90089
| | - Valery Fikkert
- *Department of Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, CA 90089
| | - Raveendra Dayam
- *Department of Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, CA 90089
| | - Myriam Witvrouw
- Division of Molecular Medicine, Katholieke Universiteit Leuven and Interdisciplinary Research Center, Katholieke Universiteit Leuven–Campus Kortrijk, Kapucijnenvoer 33, B-3000 Leuven, Flanders, Belgium
| | - Terrence R. Burke
- Laboratory of Medicinal Chemistry, Center for Cancer Research, National Institutes of Health, Frederick, MD 21702; and
| | - Christoph H. Borchers
- Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, NC 27599
- To whom correspondence may be addressed. E-mail:
or
| | - Nouri Neamati
- *Department of Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, CA 90089
- To whom correspondence may be addressed. E-mail:
or
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322
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Guiot E, Carayon K, Delelis O, Simon F, Tauc P, Zubin E, Gottikh M, Mouscadet JF, Brochon JC, Deprez E. Relationship between the oligomeric status of HIV-1 integrase on DNA and enzymatic activity. J Biol Chem 2006; 281:22707-19. [PMID: 16774912 DOI: 10.1074/jbc.m602198200] [Citation(s) in RCA: 127] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The 3'-processing of the extremities of viral DNA is the first of two reactions catalyzed by HIV-1 integrase (IN). High order IN multimers (tetramers) are required for complete integration, but it remains unclear which oligomer is responsible for the 3'-processing reaction. Moreover, IN tends to aggregate, and it is unknown whether the polymerization or aggregation of this enzyme on DNA is detrimental or beneficial for activity. We have developed a fluorescence assay based on anisotropy for monitoring release of the terminal dinucleotide product in real-time. Because the initial anisotropy value obtained after DNA binding and before catalysis depends on the fractional saturation of DNA sites and the size of IN.DNA complexes, this approach can be used to study the relationship between activity and binding/multimerization parameters in the same assay. By increasing the IN:DNA ratio, we found that the anisotropy increased but the 3'-processing activity displayed a characteristic bell-shaped behavior. The anisotropy values obtained in the first phase were predictive of subsequent activity and accounted for the number of complexes. Interestingly, activity peaked and then decreased in the second phase, whereas anisotropy continued to increase. Time-resolved fluorescence anisotropy studies showed that the most competent form for catalysis corresponds to a dimer bound to one viral DNA end, whereas higher order complexes such as aggregates predominate during the second phase when activity drops off. We conclude that a single IN dimer at each extremity of viral DNA molecules is required for 3'-processing, with a dimer of dimers responsible for the subsequent full integration.
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Affiliation(s)
- Elvire Guiot
- Laboratoire de Biotechnologie et Pharmacologie Genetique Appliquee, CNRS, UMR8113, Ecole Normale Supérieure de Cachan, 61 av du Président Wilson, 94235 Cachan, France
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323
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Maertens GN, Cherepanov P, Engelman A. Transcriptional co-activator p75 binds and tethers the Myc-interacting protein JPO2 to chromatin. J Cell Sci 2006; 119:2563-71. [PMID: 16735438 DOI: 10.1242/jcs.02995] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Transcriptional co-activator p75 is implicated in human cancer, autoimmunity and replication of human immunodeficiency virus type 1 (HIV-1) as a dominant integrase-interacting protein. Although characterized as chromatin associated, the normal biological role(s) of p75 remains fairly unclear. To gain insight into p75 function, we have characterized its cellular binding partners and report that JPO2, a recently identified Myc-binding protein, associates with p75 in vitro and in vivo. The pseudo HEAT repeat analogous topology (PHAT) domain of p75, which mediates its interaction with integrase, also mediates the interaction with JPO2, and recombinant integrase protein competes with JPO2 protein for binding to p75 in vitro. JPO2 binds p75 through a 61-residue (amino acids 58-119) region that is distinct from its Myc-interacting domain. In cells, JPO2 and p75 co-localize throughout the cell cycle, and both proteins concentrate on condensed chromosomes during mitosis. Strikingly, the association of JPO2 with chromatin strictly depends upon p75, similar to that of ectopically expressed integrase. Also similar to its effect on integrase, p75 stabilizes intracellular steady-state levels of JPO2 protein. Our results suggest a role for p75 in the Myc regulatory network, and indicate that p75 is a general adaptor protein tethering divergent factors to chromatin through its versatile integrase-binding domain.
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Affiliation(s)
- Goedele N Maertens
- Department of Cancer Immunology and AIDS, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02115, USA
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324
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Jacque JM, Stevenson M. The inner-nuclear-envelope protein emerin regulates HIV-1 infectivity. Nature 2006; 441:641-5. [PMID: 16680152 DOI: 10.1038/nature04682] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2006] [Accepted: 02/28/2006] [Indexed: 01/13/2023]
Abstract
Primate lentiviruses such as human immunodeficiency type 1 (HIV-1) have the capacity to infect non-dividing cells such as tissue macrophages. In the process, viral complementary DNA traverses the nuclear envelope to integrate within chromatin. Given the intimate association between chromatin and the nuclear envelope, we examined whether HIV-1 appropriates nuclear envelope components during infection. Here we show that emerin, an integral inner-nuclear-envelope protein, is necessary for HIV-1 infection. Infection of primary macrophages lacking emerin was abortive in that viral cDNA localized to the nucleus but integration into chromatin was inefficient, and conversion of viral cDNA to non-functional episomal cDNA increased. HIV-1 cDNA associated with emerin in vivo, and the interaction of viral cDNA with chromatin was dependent on emerin. Barrier-to-autointegration factor (BAF), the LEM (LAP, emerin, MAN) binding partner of emerin, was required for the association of viral cDNA with emerin and for the ability of emerin to support virus infection. Therefore emerin, which bridges the interface between the inner nuclear envelope and chromatin, may be necessary for chromatin engagement by viral cDNA before integration.
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Affiliation(s)
- Jean-Marc Jacque
- Program in Molecular Medicine, University of Massachusetts Medical School, 373 Plantation Street, Suite 319, Worcester, Massachusetts 01605, USA
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325
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Barr SD, Ciuffi A, Leipzig J, Shinn P, Ecker JR, Bushman FD. HIV integration site selection: targeting in macrophages and the effects of different routes of viral entry. Mol Ther 2006; 14:218-25. [PMID: 16647883 DOI: 10.1016/j.ymthe.2006.03.012] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2006] [Revised: 02/14/2006] [Accepted: 03/05/2006] [Indexed: 11/23/2022] Open
Abstract
We have studied the selection of HIV DNA integration sites in primary macrophages to investigate two questions. First, mature macrophages do not divide, allowing us to investigate whether HIV integration targeting differs between dividing cells and nondividing cells. We sequenced and analyzed 754 unique integration sites and found that integration in macrophages is favored in active transcription units (TUs), as was observed previously for other cell types. However, HIV integration in genes was slightly less favored in macrophages than in dividing PBMC or T cell lines. Second, we compared integration targeting by HIV-vector particles bearing either of two different envelope proteins (HIV R5 Env or VSV-G) to determine whether the mechanism of entry influenced subsequent integration targeting. Integration sites generated by HIV R5- or VSV-G-bearing particles showed no significant differences in their distributions in the human genome. Analysis of additional published integration site sequences also indicated that the route of entry did not affect integration site selection for other viral envelopes as well.
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Affiliation(s)
- Stephen D Barr
- Department of Microbiology, University of Pennsylvania School of Medicine, 3610 Hamilton Walk, Philadelphia, 19104-6076, USA
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326
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Turlure F, Maertens G, Rahman S, Cherepanov P, Engelman A. A tripartite DNA-binding element, comprised of the nuclear localization signal and two AT-hook motifs, mediates the association of LEDGF/p75 with chromatin in vivo. Nucleic Acids Res 2006; 34:1653-65. [PMID: 16549878 PMCID: PMC1405818 DOI: 10.1093/nar/gkl052] [Citation(s) in RCA: 143] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Lens epithelium-derived growth factor p75 (LEDGF/p75) is a DNA-binding, transcriptional co-activator that participates in HIV-1 integration site targeting. Using complementary approaches, we determined the mechanisms of LEDGF/p75 DNA-binding in vitro and chromatin-association in living cells. The binding of highly-purified, recombinant protein was assayed by surface plasmon resonance (SPR) and electrophoretic mobility gel shift. Neither assay revealed evidence for sequence-specific DNA-binding. Residues 146-197 spanning the nuclear localization signal (NLS) and two AT-hook motifs mediated non-specific DNA-binding, and DNA-binding deficient mutants retained the ability to efficiently stimulate HIV-1 integrase activity in vitro. Chromatin-association was assessed by visualizing the localization of EGFP fusion proteins in interphase and mitotic cells. Although a conserved N-terminal PWWP domain was not required for binding to condensed mitotic chromosomes, its deletion subtly affected the nucleoplasmic distribution of the protein during interphase. A dual AT-hook mutant associated normally with chromatin, yet when the mutations were combined with NLS changes or deletion of the PWWP domain, chromatin-binding function was lost. As the PWWP domain did not readily bind free DNA in vitro, our results indicate that chromatin-association is primarily affected through DNA-binding, with the PWWP domain likely contributing a protein interaction to the overall affinity of LEDGF/p75 for human chromatin.
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Affiliation(s)
| | - Goedele Maertens
- Department of Pathology, Harvard Medical SchoolBoston, MA 02115, USA
| | | | - Peter Cherepanov
- Department of Pathology, Harvard Medical SchoolBoston, MA 02115, USA
| | - Alan Engelman
- Department of Pathology, Harvard Medical SchoolBoston, MA 02115, USA
- To whom correspondence should be addressed. Tel: +1 617 632 4361; Fax: +1 617 632 3113;
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Van Maele B, Busschots K, Vandekerckhove L, Christ F, Debyser Z. Cellular co-factors of HIV-1 integration. Trends Biochem Sci 2006; 31:98-105. [PMID: 16403635 DOI: 10.1016/j.tibs.2005.12.002] [Citation(s) in RCA: 146] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2005] [Revised: 11/23/2005] [Accepted: 12/19/2005] [Indexed: 11/15/2022]
Abstract
To achieve productive infection, the reverse transcribed cDNA of human immunodeficiency virus type 1 (HIV-1) is inserted in the host cell genome. The main protein responsible for this reaction is the viral integrase. However, studies indicate that the virus is assisted by cellular proteins, or co-factors, to achieve integration into the infected cell. The barrier-to-autointegration factor (BAF) might prevent autointegration. Its ability to bridge DNA and the finding that the nuclear lamina-associated polypeptide-2alpha interacts with BAF suggest a role in nuclear structure organization. Integrase interactor 1 was found to directly interact with HIV-1 integrase and to activate its DNA-joining activity, and the high mobility group chromosomal protein A1 might approximate both long terminal repeat (LTR) ends and facilitate integrase binding by unwinding the LTR termini. Furthermore, the lens-epithelium-derived growth factor (LEDGF; also known as p75) seems to tether HIV-1 integrase to the chromosomes. Although a direct role in integration has only been demonstrated for LEDGF/p75, to date, each validated cellular co-factor for HIV-1 integration could constitute a promising new target for antiviral therapy.
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Affiliation(s)
- Bénédicte Van Maele
- Molecular Virology and Gene Therapy, Molecular Medicine, KULAK and K.U. Leuven, Kapucijnenvoer 33 3000 Leuven, Flanders, Belgium
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Bradley CM, Craigie R. Seeing is believing: structure of the catalytic domain of HIV-1 integrase in complex with human LEDGF/p75. Proc Natl Acad Sci U S A 2005; 102:17543-4. [PMID: 16314581 PMCID: PMC1308931 DOI: 10.1073/pnas.0509078102] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Christina Marchetti Bradley
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, 5 Center Drive, Bethesda, MD 20892, USA
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