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Engelman AN, Kvaratskhelia M. Multimodal Functionalities of HIV-1 Integrase. Viruses 2022; 14:926. [PMID: 35632668 PMCID: PMC9144474 DOI: 10.3390/v14050926] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Revised: 04/20/2022] [Accepted: 04/26/2022] [Indexed: 01/11/2023] Open
Abstract
Integrase is the retroviral protein responsible for integrating reverse transcripts into cellular genomes. Co-packaged with viral RNA and reverse transcriptase into capsid-encased viral cores, human immunodeficiency virus 1 (HIV-1) integrase has long been implicated in reverse transcription and virion maturation. However, the underlying mechanisms of integrase in these non-catalytic-related viral replication steps have remained elusive. Recent results have shown that integrase binds genomic RNA in virions, and that mutational or pharmacological disruption of integrase-RNA binding yields eccentric virion particles with ribonucleoprotein complexes situated outside of the capsid shell. Such viruses are defective for reverse transcription due to preferential loss of integrase and viral RNA from infected target cells. Parallel research has revealed defective integrase-RNA binding and eccentric particle formation as common features of class II integrase mutant viruses, a phenotypic grouping of viruses that display defects at steps beyond integration. In light of these new findings, we propose three new subclasses of class II mutant viruses (a, b, and c), all of which are defective for integrase-RNA binding and particle morphogenesis, but differ based on distinct underlying mechanisms exhibited by the associated integrase mutant proteins. We also assess how these findings inform the role of integrase in HIV-1 particle maturation.
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Affiliation(s)
- Alan N. Engelman
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, MA 02215, USA
- Department of Medicine, Harvard Medical School, Boston, MA 02115, USA
| | - Mamuka Kvaratskhelia
- Division of Infectious Diseases, Anschutz Medical Campus, University of Colorado School of Medicine, Aurora, CO 80045, USA
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2
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Kishimoto N, Yamamoto K, Abe T, Yasuoka N, Takamune N, Misumi S. Glucose-dependent aerobic glycolysis contributes to recruiting viral components into HIV-1 particles to maintain infectivity. Biochem Biophys Res Commun 2021; 549:187-193. [PMID: 33676187 DOI: 10.1016/j.bbrc.2021.02.071] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Accepted: 02/17/2021] [Indexed: 12/11/2022]
Abstract
The cellular environment affects optimal viral replication because viruses cannot replicate without their host cells. In particular, metabolic resources such as carbohydrates, lipids, and ATP are crucial for viral replication, which is sensitive to cellular metabolism. Intriguingly, recent studies have demonstrated that human immunodeficiency virus type 1 (HIV-1) infection induces a metabolic shift from oxidative phosphorylation to aerobic glycolysis in CD4+ T cells to produce the virus efficiently. However, the importance of aerobic glycolysis in maintaining the quality of viral components and viral infectivity has not yet been fully investigated. Here, we show that aerobic glycolysis is necessary not only to override the inhibitory effect of virion-incorporated glycolytic enzymes, but also to maintain the enzymatic activity of reverse transcriptase and the adequate packaging of envelope proteins into HIV-1 particles. To investigate the effect of metabolic remodeling on the phenotypic properties of HIV-1 produced by infected cells, we replaced glucose with galactose in the culture medium because the cells grown in galactose-containing medium are forced to carry out oxidative metabolism instead of aerobic glycolysis. We found that the packaging levels of glyceraldehyde 3-phosphate dehydrogenase, alpha-enolase and pyruvate kinase muscle type 2, which decrease HIV-1 infectivity by packaging into viral particles, are increased in progeny viruses produced by the cells grown in galactose-containing medium. Furthermore, we found that the entry and reverse transcription efficiency of the progeny viruses were reduced, which was caused by a decrease in the enzymatic activity of reverse transcriptase in the viral particles and a decrease in the packaging levels of envelope proteins and reverse transcriptase. These results indicate that the aerobic glycolysis environment in HIV-1-infected cells may contribute to the quality control of viruses.
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Affiliation(s)
- Naoki Kishimoto
- Department of Environmental and Molecular Health Sciences, Faculty of Medical and Pharmaceutical Sciences, Kumamoto University, Kumamoto, 862-0973, Japan
| | - Kengo Yamamoto
- Department of Environmental and Molecular Health Sciences, Faculty of Medical and Pharmaceutical Sciences, Kumamoto University, Kumamoto, 862-0973, Japan
| | - Towa Abe
- Department of Environmental and Molecular Health Sciences, Faculty of Medical and Pharmaceutical Sciences, Kumamoto University, Kumamoto, 862-0973, Japan
| | - Norito Yasuoka
- Department of Environmental and Molecular Health Sciences, Faculty of Medical and Pharmaceutical Sciences, Kumamoto University, Kumamoto, 862-0973, Japan
| | - Nobutoki Takamune
- Kumamoto Innovative Development Organization, Kumamoto University, Kumamoto, 860-8555, Japan
| | - Shogo Misumi
- Department of Environmental and Molecular Health Sciences, Faculty of Medical and Pharmaceutical Sciences, Kumamoto University, Kumamoto, 862-0973, Japan.
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3
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Chang CC, Hsia KC. More than a zip code: global modulation of cellular function by nuclear localization signals. FEBS J 2020; 288:5569-5585. [PMID: 33296547 DOI: 10.1111/febs.15659] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2020] [Revised: 12/03/2020] [Accepted: 12/07/2020] [Indexed: 12/27/2022]
Abstract
Extensive structural and functional studies have been carried out in the field of nucleocytoplasmic transport. Nuclear transport factors, such as Importin-α/-β, recognize nuclear localization signals (NLSs) on cargo, and together with the small GTPase Ran, facilitate their nuclear localization. However, it is now emerging that binding of nuclear transport factors to NLSs not only mediates nuclear transport but also contributes to a variety of cellular functions in eukaryotes. Here, we describe recent advances that reveal how NLSs facilitate diverse cellular functions beyond nuclear transport activity. We review separately NLS-mediated regulatory mechanisms at different levels of biological organization, including (a) assembly of higher-order structures; (b) cellular organelle dynamics; and (c) modulation of cellular stress responses and viral infections. Finally, we provide mechanistic insights into how NLSs can regulate such a broad range of functions via their structural and biochemical properties.
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Affiliation(s)
- Chih-Chia Chang
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan
| | - Kuo-Chiang Hsia
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan.,Institute of Biochemistry and Molecular Biology, College of Life Sciences, National Yang-Ming University, Taipei, Taiwan
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4
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Kishimoto N, Yamamoto K, Iga N, Kirihara C, Abe T, Takamune N, Misumi S. Alpha-enolase in viral target cells suppresses the human immunodeficiency virus type 1 integration. Retrovirology 2020; 17:31. [PMID: 32917235 PMCID: PMC7488571 DOI: 10.1186/s12977-020-00539-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Accepted: 09/04/2020] [Indexed: 12/30/2022] Open
Abstract
Background A protein exhibiting more than one biochemical function is termed a moonlighting protein. Glycolytic enzymes are typical moonlighting proteins, and these enzymes control the infection of various viruses. Previously, we reported that glyceraldehyde 3-phosphate dehydrogenase (GAPDH) and alpha-enolase (ENO1) are incorporated into human immunodeficiency virus type 1 (HIV-1) particles from viral producer cells and suppress viral reverse transcription independently each other. However, it remains unclear whether these proteins expressed in viral target cells affect the early phase of HIV-1 replication. Results Here we show that the GAPDH expression level in viral target cells does not affect the early phase of HIV-1 replication, but ENO1 has a capacity to suppress viral integration in viral target cells. In contrast to GAPDH, suppression of ENO1 expression by RNA interference in the target cells increased viral infectivity, but had no effect on the expression levels of the HIV-1 receptors CD4, CCR5 and CXCR4 and on the level of HIV-1 entry. Quantitative analysis of HIV-1 reverse transcription products showed that the number of copies of the late products (R/gag) and two-long-terminal-repeat circular forms of viral cDNAs did not change but that of the integrated (Alu-gag) form increased. In contrast, overexpression of ENO1 in viral target cells decreased viral infectivity owing to the low viral integration efficiency. Results of subcellular fractionation experiments suggest that the HIV integration at the nucleus was negatively regulated by ENO1 localized in the nucleus. In addition, the overexpression of ENO1 in both viral producer cells and target cells most markedly suppressed the viral replication. Conclusions These results indicate that ENO1 in the viral target cells prevents HIV-1 integration. Importantly, ENO1, but not GAPDH, has the bifunctional inhibitory activity against HIV-1 replication. The results provide and new insights into the function of ENO1 as a moonlighting protein in HIV-1 infection.
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Affiliation(s)
- Naoki Kishimoto
- Department of Environmental and Molecular Health Sciences, Faculty of Medical and Pharmaceutical Sciences, Kumamoto University, Kumamoto, 862-0973, Japan
| | - Kengo Yamamoto
- Department of Environmental and Molecular Health Sciences, Faculty of Medical and Pharmaceutical Sciences, Kumamoto University, Kumamoto, 862-0973, Japan
| | - Nozomi Iga
- Department of Environmental and Molecular Health Sciences, Faculty of Medical and Pharmaceutical Sciences, Kumamoto University, Kumamoto, 862-0973, Japan
| | - Chie Kirihara
- Department of Environmental and Molecular Health Sciences, Faculty of Medical and Pharmaceutical Sciences, Kumamoto University, Kumamoto, 862-0973, Japan
| | - Towa Abe
- Department of Environmental and Molecular Health Sciences, Faculty of Medical and Pharmaceutical Sciences, Kumamoto University, Kumamoto, 862-0973, Japan
| | - Nobutoki Takamune
- Kumamoto Innovative Development Organization, Kumamoto University, Kumamoto, 860-8555, Japan
| | - Shogo Misumi
- Department of Environmental and Molecular Health Sciences, Faculty of Medical and Pharmaceutical Sciences, Kumamoto University, Kumamoto, 862-0973, Japan.
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5
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Singh SP, Raja S, Mahalingam S. Viral protein X unlocks the nuclear pore complex through a human Nup153-dependent pathway to promote nuclear translocation of the lentiviral genome. Mol Biol Cell 2020; 31:304-317. [PMID: 31913756 PMCID: PMC7183765 DOI: 10.1091/mbc.e19-08-0438] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Simian immunodeficiency virus (SIV) and human immunodeficiency virus 2 (HIV-2) display unique ability to infect nondividing target cells. Viral protein X (Vpx) of HIV-2/SIV is known to be involved in the nuclear import of viral genome in nondividing cells, but the mechanism remains poorly understood. In the present investigation for the first time we provide evidence that Vpx of SIVsmPBj1.9 physically interacts with human nucleoporin 153 (Nup153), which is known to provide a docking site for protein-cargo complexes at the nuclear pore complex (NPC). Results from superresolution-structured illumination microscopy studies reveal that Vpx interaction with NPC-associated Nup153 is critical for its efficient nuclear translocation. Virion-associated MAPK/ERK-2-mediated phosphorylation of Vpx plays a critical role in its interaction with human Nup153 and this interaction was found to be evolutionarily conserved in various SIV isolates and HIV-2. Interestingly, MAPK/ERK-2 packaging defective SIV failed to promote the efficient nuclear import of viral genome and suggests that MAPK/ERK-2-mediated Vpx phosphorylation is important for its interaction with Nup153, which is critical for lentiviruses to establish infection in nondividing target cells. Together, our data elucidate the mechanism by which Vpx orchestrates the challenging task of nuclear translocation of HIV-2/SIV genome in nondividing target cells.
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Affiliation(s)
- Satya Prakash Singh
- Laboratory of Molecular Cell Biology, Indian Institute of Technology-Madras, Chennai 600 036, India
| | - Sebastian Raja
- Laboratory of Molecular Cell Biology, Indian Institute of Technology-Madras, Chennai 600 036, India
| | - Sundarasamy Mahalingam
- Laboratory of Molecular Cell Biology, Indian Institute of Technology-Madras, Chennai 600 036, India.,National Cancer Tissue Biobank, Bhupat and Jyoti Mehta School of Biosciences, Department of Biotechnology, Indian Institute of Technology-Madras, Chennai 600 036, India
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El Khoury L, El Hage K, Piquemal JP, Fermandjian S, Maroun RG, Gresh N, Hobaika Z. Spectrometric and computational studies of the binding of HIV-1 integrase inhibitors to viral DNA extremities. PEERJ PHYSICAL CHEMISTRY 2019. [DOI: 10.7717/peerj-pchem.6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Three integrase strand transfer inhibitors are in intensive clinical use, raltegravir (RAL), elvitegravir (EVG) and dolutegravir (DTG). The onset of integrase resistance mutations limits their therapeutic efficiency. As put forth earlier, the drug affinity for the intasome could be improved by targeting preferentially the retroviral nucleobases, which are little, if at all, mutation-prone. We report experimental results of anisotropy fluorescence titrations of viral DNA by these three drugs. These show the DTG > EVG > RAL ranking of their inhibitory activities of the intasome to correspond to that of their free energies of binding, ∆Gs, to retroviral DNA, and that such a ranking is only governed by the binding enthalpies, ∆H, the entropy undergoing marginal variations. We sought whether this ranking might be reproduced through quantum chemistry (QC) Density Functional Theory calculations of intermolecular interaction energies between simplified models consisting of sole halobenzene ring and the highly conserved retroviral nucleobases G4 and C16. These calculations showed that binding of EVG has a small preference over DTG, while RAL ranked third. This indicates that additional interactions of the diketoacid parts of the drugs with DNA could be necessary to further enable preferential binding of DTG. The corresponding ∆Etotvalues computed with a polarizable molecular mechanics/dynamics procedure, Sum of Interactions Between Fragments Ab initio computed (SIBFA), showed good correlations with this ∆E(QC) ranking. These validations are an important step toward the use of polarizable molecular dynamics simulations on DTG or EVG derivatives in their complexes with the complete intasome, an application now motivated and enabled by the advent of currently developed and improved massively parallel software.
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Affiliation(s)
- Léa El Khoury
- Laboratoire de Chimie Théorique, UMR7616 CNRS, Sorbonne Université, Paris, France
- UR EGP, Centre d’Analyses et de Recherche, Faculté des Sciences, Université Saint-Joseph de Beyrouth, Beirut, Lebanon
- Present address: Department of Pharmaceutical Sciences, University of California, Irvine, Irvine, CA, USA
| | - Krystel El Hage
- Chemistry and Biology Nucleo(s)tides and Immunology for Therapy (CBNIT), UMR 8601 CNRS, UFR Biomedicale, Paris, France
- Present address: Laboratoire Structure-Activité des Biomolécules Normales et Pathologiques, INSERM U829, Université Evry-Val d’Essonne, Evry, France
| | - Jean-Philip Piquemal
- UR EGP, Centre d’Analyses et de Recherche, Faculté des Sciences, Université Saint-Joseph de Beyrouth, Beirut, Lebanon
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX, USA
- Institut Universitaire de France, Paris, France
| | - Serge Fermandjian
- Chemistry and Biology Nucleo(s)tides and Immunology for Therapy (CBNIT), UMR 8601 CNRS, UFR Biomedicale, Paris, France
| | - Richard G. Maroun
- UR EGP, Centre d’Analyses et de Recherche, Faculté des Sciences, Université Saint-Joseph de Beyrouth, Beirut, Lebanon
| | - Nohad Gresh
- Laboratoire de Chimie Théorique, UMR7616 CNRS, Sorbonne Université, Paris, France
| | - Zeina Hobaika
- UR EGP, Centre d’Analyses et de Recherche, Faculté des Sciences, Université Saint-Joseph de Beyrouth, Beirut, Lebanon
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7
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Larguet F, Caté C, Barbeau B, Rassart E, Edouard E. Histone deacetylase 1 interacts with HIV-1 Integrase and modulates viral replication. Virol J 2019; 16:138. [PMID: 31744547 PMCID: PMC6862858 DOI: 10.1186/s12985-019-1249-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Accepted: 11/05/2019] [Indexed: 01/09/2023] Open
Abstract
Background HIV-1 hijacks the cellular machinery for its own replication through protein-protein interactions between viral and host cell factors. One strategy against HIV-1 infection is thus to target these key protein complexes. As the integration of reverse transcribed viral cDNA into a host cell chromosome is an essential step in the HIV-1 life cycle, catalyzed by the viral integrase and other important host factors, we aimed at identifying new integrase binding partners through a novel approach. Methods A LTR-derived biotinylated DNA fragment complexed with the integrase on magnetic beads was incubated with extracts from integrase-expressing 293 T cells. Liquid chromatography-mass spectrometry/mass spectrometry and co-immunoprecipitation/pull-down experiments were used for the identification of binding partners. Transfections of histone deacetylase 1 (HDAC1) expression vectors and/or specific siRNA were conducted in HeLa-CD4 and 293 T cells followed by infection with fully infectious NL4–3 and luciferase-expressing pseudotyped viruses or by proviral DNA transfection. Fully infectious and pseudotyped viruses produced from HDAC1-silenced 293 T cells were tested for their infectivity toward HeLa-CD4 cells, T cell lines and primary CD4+ T cells. Late RT species and integrated viral DNA were quantified by qPCR and infectivity was measured by luciferase activity and p24 ELISA assay. Results were analyzed by the Student’s t-test. Results Using our integrase-LTR bait approach, we successfully identified new potential integrase-binding partners, including HDAC1. We further confirmed that HDAC1 interacted with the HIV-1 integrase in co-immunoprecipitation and pull-down experiments. HDAC1 knockdown in infected HeLa cells was shown to interfere with an early preintegration step of the HIV-1 replication cycle, which possibly involves reverse transcription. We also observed that, while HDAC1 overexpression inhibited HIV-1 expression after integration, HDAC1 knockdown had no effect on this step. In virus producer cells, HDAC1 knockdown had a limited impact on virus infectivity in either cell lines or primary CD4+ T cells. Conclusions Our results show that HDAC1 interacts with the HIV-1 integrase and affects virus replication before and after integration. Overall, HDAC1 appears to facilitate HIV-1 replication with a major effect on a preintegration step, which likely occurs at the reverse transcription step.
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Affiliation(s)
- Fadila Larguet
- Département des sciences biologiques, and Centre de recherche BioMed, Université du Québec à Montréal, Montréal, QC, Canada
| | - Clément Caté
- Département des sciences biologiques, and Centre de recherche BioMed, Université du Québec à Montréal, Montréal, QC, Canada
| | - Benoit Barbeau
- Département des sciences biologiques, and Centre de recherche BioMed, Université du Québec à Montréal, Montréal, QC, Canada
| | - Eric Rassart
- Département des sciences biologiques, and Centre de recherche BioMed, Université du Québec à Montréal, Montréal, QC, Canada.
| | - Elsy Edouard
- Département des sciences biologiques, and Centre de recherche BioMed, Université du Québec à Montréal, Montréal, QC, Canada.
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8
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Dochi T, Akita A, Kishimoto N, Takamune N, Misumi S. Trametinib suppresses HIV-1 replication by interfering with the disassembly of human immunodeficiency virus type 1 capsid core. Biochem Biophys Res Commun 2017; 495:1846-1850. [PMID: 29197575 DOI: 10.1016/j.bbrc.2017.11.177] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Accepted: 11/28/2017] [Indexed: 11/15/2022]
Abstract
Our previous study showed that the phosphorylation of a highly conserved serine residue, Ser16 in the human immunodeficiency virus type 1 (HIV-1) capsid (CA) protein is promoted by virion-incorporated extracellular signal-regulated kinase 2 (ERK2) and required for proper peptidyl-prolyl isomerase (Pin1)-mediated uncoating. Interestingly, western blot analysis demonstrated that phosphorylated/activated mitogen-activated protein kinase kinase 1/2 (MEK1/2), the upstream activator of ERK2, as well as ERK2 are incorporated into virions. Here, we show that the MEK1/2 selective allosteric inhibitor Trametinib reduces HIV-1 infectivity via the decrease in virion-incorporated ERK2 phosphorylation. The treatment of chronic HIV-1-infected T-cell line, CEM/LAV-1 cells with Trametinib results in a decrease in ERK2 phosphorylation in the virions. The viruses have relatively low infectivity and impaired reverse transcription. Cell-based fate-of-capsid uncoating assay showed that the reduction in infectivity was caused by a functional impairment of the uncoating process. Furthermore, the viruses from Trametinib-treated CEM/LAV-1 cells also showed decreased reverse transcription efficiency and attenuated multiple rounds of replication in human peripheral blood mononuclear cells (PBMCs). Taken together, these findings suggest that Trametinib suppresses HIV-1 replication by abrogating the proper disassembly of CA core.
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Affiliation(s)
- Takeo Dochi
- Department of Environmental and Molecular Health Sciences, Faculty of Medical and Pharmaceutical Sciences, Kumamoto University, Kumamoto 862-0973, Japan
| | - Ayano Akita
- Department of Environmental and Molecular Health Sciences, Faculty of Medical and Pharmaceutical Sciences, Kumamoto University, Kumamoto 862-0973, Japan
| | - Naoki Kishimoto
- Department of Environmental and Molecular Health Sciences, Faculty of Medical and Pharmaceutical Sciences, Kumamoto University, Kumamoto 862-0973, Japan
| | - Nobutoki Takamune
- Innovative Collaboration Organization, Kumamoto University, Kumamoto 860-8555, Japan
| | - Shogo Misumi
- Department of Environmental and Molecular Health Sciences, Faculty of Medical and Pharmaceutical Sciences, Kumamoto University, Kumamoto 862-0973, Japan.
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9
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Critical Contribution of Tyr15 in the HIV-1 Integrase (IN) in Facilitating IN Assembly and Nonenzymatic Function through the IN Precursor Form with Reverse Transcriptase. J Virol 2016; 91:JVI.02003-16. [PMID: 27795445 DOI: 10.1128/jvi.02003-16] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Accepted: 10/07/2016] [Indexed: 12/28/2022] Open
Abstract
Nonenzymatic roles for HIV-1 integrase (IN) at steps prior to the enzymatic integration step have been reported. To obtain structural and functional insights into the nonenzymatic roles of IN, we performed genetic analyses of HIV-1 IN, focusing on a highly conserved Tyr15 in the N-terminal domain (NTD), which has previously been shown to regulate an equilibrium state between two NTD dimer conformations. Replacement of Tyr15 with alanine, histidine, or tryptophan prevented HIV-1 infection and caused severe impairment of reverse transcription without apparent defects in reverse transcriptase (RT) or in capsid disassembly kinetics after entry into cells. Cross-link analyses of recombinant IN proteins demonstrated that lethal mutations of Tyr15 severely impaired IN structure for assembly. Notably, replacement of Tyr15 with phenylalanine was tolerated for all IN functions, demonstrating that a benzene ring of the aromatic side chain is a key moiety for IN assembly and functions. Additional mutagenic analyses based on previously proposed tetramer models for IN assembly suggested a key role of Tyr15 in facilitating the hydrophobic interaction among IN subunits, together with other proximal residues within the subunit interface. A rescue experiment with a mutated HIV-1 with RT and IN deleted (ΔRT ΔIN) and IN and RT supplied in trans revealed that the nonenzymatic IN function might be exerted through the IN precursor conjugated with RT (RT-IN). Importantly, the lethal mutations of Tyr15 significantly reduced the RT-IN function and assembly. Taken together, Tyr15 seems to play a key role in facilitating the proper assembly of IN and RT on viral RNA through the RT-IN precursor form. IMPORTANCE Inhibitors of the IN enzymatic strand transfer function (INSTI) have been applied in combination antiretroviral therapies to treat HIV-1-infected patients. Recently, allosteric IN inhibitors (ALLINIs) that interact with HIV-1 IN residues, the locations of which are distinct from the catalytic sites targeted by INSTI, have been discovered. Importantly, ALLINIs affect the nonenzymatic role(s) of HIV-1 IN, providing a rationale for the development of next-generation IN inhibitors with a mechanism that is distinct from that of INSTI. Here, we demonstrate that Tyr15 in the HIV-1 IN NTD plays a critical role during IN assembly by facilitating the hydrophobic interaction of the NTD with the other domains of IN. Importantly, we found that the functional assembly of IN through its fusion form with RT is critical for IN to exert its nonenzymatic function. Our results provide a novel mechanistic insight into the nonenzymatic function of HIV-1 IN and its prevention.
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10
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Abstract
The integration of a DNA copy of the viral RNA genome into host chromatin is the defining step of retroviral replication. This enzymatic process is catalyzed by the virus-encoded integrase protein, which is conserved among retroviruses and LTR-retrotransposons. Retroviral integration proceeds via two integrase activities: 3'-processing of the viral DNA ends, followed by the strand transfer of the processed ends into host cell chromosomal DNA. Herein we review the molecular mechanism of retroviral DNA integration, with an emphasis on reaction chemistries and architectures of the nucleoprotein complexes involved. We additionally discuss the latest advances on anti-integrase drug development for the treatment of AIDS and the utility of integrating retroviral vectors in gene therapy applications.
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Affiliation(s)
- Paul Lesbats
- Clare Hall Laboratories, The Francis Crick Institute , Blanche Lane, South Mimms, EN6 3LD, U.K
| | - Alan N Engelman
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute and Department of Medicine, Harvard Medical School , 450 Brookline Avenue, Boston, Massachusetts 02215 United States
| | - Peter Cherepanov
- Clare Hall Laboratories, The Francis Crick Institute , Blanche Lane, South Mimms, EN6 3LD, U.K.,Imperial College London , St-Mary's Campus, Norfolk Place, London, W2 1PG, U.K
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11
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Fate of HIV-1 cDNA intermediates during reverse transcription is dictated by transcription initiation site of virus genomic RNA. Sci Rep 2015; 5:17680. [PMID: 26631448 PMCID: PMC4668388 DOI: 10.1038/srep17680] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2015] [Accepted: 11/04/2015] [Indexed: 02/07/2023] Open
Abstract
Retroviral reverse transcription is accomplished by sequential strand-transfers of partial cDNA intermediates copied from viral genomic RNA. Here, we revealed an unprecedented role of 5′-end guanosine (G) of HIV-1 genomic RNA for reverse transcription. Based on current consensus for HIV-1 transcription initiation site, HIV-1 transcripts possess a single G at 5′-ends (G1-form). However, we found that HIV-1 transcripts with additional Gs at 5′-ends (G2- and G3-forms) were abundantly expressed in infected cells by using alternative transcription initiation sites. The G2- and G3-forms were also detected in the virus particle, although the G1-form predominated. To address biological impact of the 5′-G number, we generated HIV clone DNA to express the G1-form exclusively by deleting the alternative initiation sites. Virus produced from the clone showed significantly higher strand-transfer of minus strong-stop cDNA (-sscDNA). The in vitro assay using synthetic HIV-1 RNAs revealed that the abortive forms of -sscDNA were abundantly generated from the G3-form RNA, but dramatically reduced from the G1-form. Moreover, the strand-transfer of -sscDNA from the G1-form was prominently stimulated by HIV-1 nucleocapsid. Taken together, our results demonstrated that the 5′-G number that corresponds to HIV-1 transcription initiation site was critical for successful strand-transfer of -sscDNA during reverse transcription.
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12
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Ogawa M, Takemoto Y, Sumi S, Inoue D, Kishimoto N, Takamune N, Shoji S, Suzu S, Misumi S. ATP generation in a host cell in early-phase infection is increased by upregulation of cytochrome c oxidase activity via the p2 peptide from human immunodeficiency virus type 1 Gag. Retrovirology 2015; 12:97. [PMID: 26577226 PMCID: PMC4650201 DOI: 10.1186/s12977-015-0224-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2015] [Accepted: 11/02/2015] [Indexed: 11/26/2022] Open
Abstract
Background Human immunodeficiency virus type 1 (HIV-1) must take advantage of its own proteins with two or more functions to successfully replicate. Although many attempts have been made to determine the function of viral proteins encoded in the HIV-1 genome, the role of the p2 peptide, a spacer between the capsid and the nucleocapsid in HIV-1 Gag in early-phase HIV infection still remains unclarified. Results In this study, we show that the p2 peptide enhances HIV-1 acute infection by increasing intracellular ATP production via the activation of mitochondrial cytochrome c oxidase (MT-CO) involved in the respiratory chain. We found that cell-permeable p2-peptide-treated cells were more effectively infected by HIV-1 than control cells. To characterize the effect of the p2 peptide on HIV-1 replication in MAGIC-5 cells, various HIV-1 cDNA products were measured by quantitative real-time PCR. The levels of the late (R/gag), 2-LTR circular (2-LTR), and integrated (Alu) forms of viral cDNAs increased in the presence of the p2 peptide. Interestingly, yeast two-hybrid analysis revealed a novel interaction between the p2 peptide and the mitochondrial intermembrane space domain (N214–F235) of MT-CO subunit I (MT-CO1). Mutational analysis indicated that Gln6 in the p2 peptide is important for the interaction with MT-CO1. The p2 peptide activated MT-CO1 in vitro in a concentration-dependent manner, and fluorescence-microscopy analysis demonstrated that the p2 peptide had a significant effect on mitochondrial targeting. Furthermore, the analysis of HIV-1 lacking a functional p2 peptide demonstrated the inhibition of intracellular ATP production in MT-4 cells and monocyte-derived macrophages (MDMs) and a decrease in reverse transcription efficiency following infection of MT-4 cells and MDMs. Conclusions These findings provide evidence that the p2 peptide is a viral positive allosteric modulator of MT-CO and the increased intracellular ATP production after HIV infection in a p2-peptide-dependent manner is essential for efficient reverse transcription in early-phase HIV-1 infection.
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Affiliation(s)
- Minako Ogawa
- Department of Environmental and Molecular Health Sciences, Faculty of Medical and Pharmaceutical Sciences, Kumamoto University, Kumamoto, 862-0973, Japan.
| | - Yuki Takemoto
- Department of Environmental and Molecular Health Sciences, Faculty of Medical and Pharmaceutical Sciences, Kumamoto University, Kumamoto, 862-0973, Japan.
| | - Shintaro Sumi
- Department of Environmental and Molecular Health Sciences, Faculty of Medical and Pharmaceutical Sciences, Kumamoto University, Kumamoto, 862-0973, Japan.
| | - Daisuke Inoue
- Department of Environmental and Molecular Health Sciences, Faculty of Medical and Pharmaceutical Sciences, Kumamoto University, Kumamoto, 862-0973, Japan.
| | - Naoki Kishimoto
- Department of Environmental and Molecular Health Sciences, Faculty of Medical and Pharmaceutical Sciences, Kumamoto University, Kumamoto, 862-0973, Japan.
| | - Nobutoki Takamune
- Innovative Collaboration Organization, Kumamoto University, Kumamoto, 860-8555, Japan.
| | - Shozo Shoji
- Department of Environmental and Molecular Health Sciences, Faculty of Medical and Pharmaceutical Sciences, Kumamoto University, Kumamoto, 862-0973, Japan.
| | - Shinya Suzu
- Center for AIDS Research, Kumamoto University, Kumamoto, 860-0811, Japan.
| | - Shogo Misumi
- Department of Environmental and Molecular Health Sciences, Faculty of Medical and Pharmaceutical Sciences, Kumamoto University, Kumamoto, 862-0973, Japan.
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Interaction between Reverse Transcriptase and Integrase Is Required for Reverse Transcription during HIV-1 Replication. J Virol 2015; 89:12058-69. [PMID: 26401032 DOI: 10.1128/jvi.01471-15] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Accepted: 09/10/2015] [Indexed: 12/24/2022] Open
Abstract
UNLABELLED Human immunodeficiency virus type 1 (HIV-1) replication requires reverse transcription of its RNA genome into a double-stranded cDNA copy, which is then integrated into the host cell chromosome. The essential steps of reverse transcription and integration are catalyzed by the viral enzymes reverse transcriptase (RT) and integrase (IN), respectively. In vitro, HIV-1 RT can bind with IN, and the C-terminal domain (CTD) of IN is necessary and sufficient for this binding. To better define the RT-IN interaction, we performed nuclear magnetic resonance (NMR) spectroscopy experiments to map a binding surface on the IN CTD in the presence of RT prebound to a duplex DNA construct that mimics the primer-binding site in the HIV-1 genome. To determine the biological significance of the RT-IN interaction during viral replication, we used the NMR chemical shift mapping information as a guide to introduce single amino acid substitutions of nine different residues on the putative RT-binding surface in the IN CTD. We found that six viral clones bearing such IN substitutions (R231E, W243E, G247E, A248E, V250E, and I251E) were noninfectious. Further analyses of the replication-defective IN mutants indicated that the block in replication took place specifically during early reverse transcription. The recombinant INs purified from these mutants, though retaining enzymatic activities, had diminished ability to bind RT in a cosedimentation assay. The results indicate that the RT-IN interaction is functionally relevant during the reverse transcription step of the HIV-1 life cycle. IMPORTANCE To establish a productive infection, human immunodeficiency virus type 1 (HIV-1) needs to reverse transcribe its RNA genome to create a double-stranded DNA copy and then integrate this viral DNA genome into the chromosome of the host cell. These two essential steps are catalyzed by the HIV-1 enzymes reverse transcriptase (RT) and integrase (IN), respectively. We have shown previously that IN physically interacts with RT, but the importance of this interaction during HIV-1 replication has not been fully characterized. In this study, we have established the biological significance of the HIV-1 RT-IN interaction during the viral life cycle by demonstrating that altering the RT-binding surface on IN disrupts both reverse transcription and viral replication. These findings contribute to our understanding of the RT-IN binding mechanism, as well as indicate that the RT-IN interaction can be exploited as a new antiviral drug target.
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Levin A, Hayouka Z, Friedler A, Loyter A. Nucleocytoplasmic shuttling of HIV-1 integrase is controlled by the viral Rev protein. Nucleus 2014. [DOI: 10.4161/nucl.11300] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
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15
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Dochi T, Nakano T, Inoue M, Takamune N, Shoji S, Sano K, Misumi S. Phosphorylation of human immunodeficiency virus type 1 capsid protein at serine 16, required for peptidyl-prolyl isomerase-dependent uncoating, is mediated by virion-incorporated extracellular signal-regulated kinase 2. J Gen Virol 2014; 95:1156-1166. [PMID: 24509437 DOI: 10.1099/vir.0.060053-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
We reported previously that Pin1 facilitates human immunodeficiency virus type 1 (HIV-1) uncoating by interacting with the capsid core through the phosphorylated Ser(16)-Pro(17) motif. However, the specific kinase responsible for Ser(16) phosphorylation has remained unknown. Here, we showed that virion-associated extracellular signal-regulated kinase 2 (ERK2) phosphorylates Ser(16). The characterization of immature virions produced by exposing chronically HIV-1LAV-1-infected CEM/LAV-1 cells to 10 µM saquinavir indicated that Ser(16) is phosphorylated after the initiation of Pr55(Gag) processing. Furthermore, a mass spectrometry-based in vitro kinase assay demonstrated that ERK2 specifically phosphorylated the Ser(16) residue in the Ser(16)-Pro(17) motif-containing substrate. The treatment of CEM/LAV-1 cells with the ERK2 inhibitor sc-222229 decreased the Ser(16) phosphorylation level inside virions, and virus partially defective in Ser(16) phosphorylation showed impaired reverse transcription and attenuated replication owing to attenuated Pin1-dependent uncoating. Furthermore, the suppression of ERK2 expression by RNA interference in CEM/LAV-1 cells resulted in suppressed ERK2 packaging inside virions and decreased the Ser(16) phosphorylation level inside virions. Interestingly, the ERK2-packaging-defective virus showed impaired reverse transcription and attenuated HIV-1 replication. Taken together, these findings provide insights into the as-yet-obscure processes in Pin1-dependent HIV-1 uncoating.
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Affiliation(s)
- Takeo Dochi
- Department of Pharmaceutical Biochemistry, Faculty of Medical and Pharmaceutical Sciences, Kumamoto University, Kumamoto 862-0973, Japan
| | - Takashi Nakano
- Department of Microbiology and Infection Control, Osaka Medical College, Osaka 569-8686, Japan
| | - Mutsumi Inoue
- Department of Pharmaceutical Biochemistry, Faculty of Medical and Pharmaceutical Sciences, Kumamoto University, Kumamoto 862-0973, Japan
| | - Nobutoki Takamune
- Department of Pharmaceutical Biochemistry, Faculty of Medical and Pharmaceutical Sciences, Kumamoto University, Kumamoto 862-0973, Japan
| | - Shozo Shoji
- Department of Pharmaceutical Biochemistry, Faculty of Medical and Pharmaceutical Sciences, Kumamoto University, Kumamoto 862-0973, Japan
| | - Kouichi Sano
- Department of Microbiology and Infection Control, Osaka Medical College, Osaka 569-8686, Japan
| | - Shogo Misumi
- Department of Pharmaceutical Biochemistry, Faculty of Medical and Pharmaceutical Sciences, Kumamoto University, Kumamoto 862-0973, Japan
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Natural single-nucleotide polymorphisms in the 3' region of the HIV-1 pol gene modulate viral replication ability. J Virol 2014; 88:4145-60. [PMID: 24478432 DOI: 10.1128/jvi.01859-13] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
UNLABELLED We previously showed that prototype macaque-tropic human immunodeficiency virus type 1 (HIV-1) acquired nonsynonymous growth-enhancing mutations within a narrow genomic region during the adaptation process in macaque cells. These adaptive mutations were clustered in the 3' region of the pol gene, encoding a small portion of the C-terminal domain of integrase (IN). Mutations in HIV-1 IN have been reported to have pleiotropic effects on both the early and late phases in viral replication. cis-acting functions in the IN-coding sequence for viral gene expression have also been reported. We here demonstrated that the adaptive mutations promoted viral growth by increasing virion production with no positive effects on the early replication phase. Synonymous codon alterations in one of the adaptive mutations influenced virion production levels, which suggested nucleotide-dependent regulation. Indeed, when the single-nucleotide natural polymorphisms observed in the 3' regions of 196 HIV-1/simian immunodeficiency virus (SIVcpz) pol genes (nucleotides [nt] 4895 to 4929 for HIV-1 NL4-3) were introduced into macaque- and human-tropic HIV-1 clones, more than half exhibited altered replication potentials. Moreover, single-nucleotide mutations caused parallel increases or decreases in the expression levels of viral late proteins and viral replication potentials. We also showed that the overall expression profiles of viral mRNAs were markedly changed by single-nucleotide mutations. These results demonstrate that the 3' region of the HIV-1 pol gene (nt 4895 to 4929) can alter viral replication potential by modulating the expression pattern of viral mRNAs in a nucleotide-dependent manner. IMPORTANCE Viruses have the plasticity to adapt themselves under various constraints. HIV-1 can mutate and evolve in growth-restrictive cells by acquiring adaptive changes in its genome. We have previously identified some growth-enhancing mutations in a narrow region of the IN-coding sequence, in which a number of cis-acting elements are located. We now focus on the virological significance of this pol gene region and the mechanistic basis underlying its effects on viral replication. We have found several naturally occurring synonymous mutations within this region that alter viral replication potentials. The effects caused by these natural single-nucleotide polymorphisms are linked to the definite expression patterns of viral mRNAs. We show here that the nucleotide sequence of the pol gene (nucleotides 4895 to 4929 for HIV-1 NL4-3) plays an important role in HIV-1 replication by modulating viral gene expression.
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Desimmie BA, Schrijvers R, Demeulemeester J, Borrenberghs D, Weydert C, Thys W, Vets S, Van Remoortel B, Hofkens J, De Rijck J, Hendrix J, Bannert N, Gijsbers R, Christ F, Debyser Z. LEDGINs inhibit late stage HIV-1 replication by modulating integrase multimerization in the virions. Retrovirology 2013; 10:57. [PMID: 23721378 PMCID: PMC3671127 DOI: 10.1186/1742-4690-10-57] [Citation(s) in RCA: 117] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2013] [Accepted: 05/07/2013] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND LEDGINs are novel allosteric HIV integrase (IN) inhibitors that target the lens epithelium-derived growth factor (LEDGF)/p75 binding pocket of IN. They block HIV-1 integration by abrogating the interaction between LEDGF/p75 and IN as well as by allosterically inhibiting the catalytic activity of IN. RESULTS Here we demonstrate that LEDGINs reduce the replication capacity of HIV particles produced in their presence. We systematically studied the molecular basis of this late effect of LEDGINs and demonstrate that HIV virions produced in their presence display a severe replication defect. Both the late effect and the previously described, early effect on integration contribute to LEDGIN antiviral activity as shown by time-of-addition, qPCR and infectivity assays. The late effect phenotype requires binding of LEDGINs to integrase without influencing proteolytic cleavage or production of viral particles. LEDGINs augment IN multimerization during virion assembly or in the released viral particles and severely hamper the infectivity of progeny virions. About 70% of the particles produced in LEDGIN-treated cells do not form a core or display aberrant empty cores with a mislocalized electron-dense ribonucleoprotein. The LEDGIN-treated virus displays defective reverse transcription and nuclear import steps in the target cells. The LEDGIN effect is possibly exerted at the level of the Pol precursor polyprotein. CONCLUSION Our results suggest that LEDGINs modulate IN multimerization in progeny virions and impair the formation of regular cores during the maturation step, resulting in a decreased infectivity of the viral particles in the target cells. LEDGINs thus profile as unique antivirals with combined early (integration) and late (IN assembly) effects on the HIV replication cycle.
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Affiliation(s)
- Belete Ayele Desimmie
- Department of Pharmaceutical and Pharmacological Sciences, Laboratory for Molecular Virology and Gene Therapy, KU Leuven, Kapucijnenvoer 33, Leuven, Flanders, 3000, Belgium
| | - Rik Schrijvers
- Department of Pharmaceutical and Pharmacological Sciences, Laboratory for Molecular Virology and Gene Therapy, KU Leuven, Kapucijnenvoer 33, Leuven, Flanders, 3000, Belgium
| | - Jonas Demeulemeester
- Department of Pharmaceutical and Pharmacological Sciences, Laboratory for Molecular Virology and Gene Therapy, KU Leuven, Kapucijnenvoer 33, Leuven, Flanders, 3000, Belgium
| | - Doortje Borrenberghs
- Laboratory for Photochemistry and Spectroscopy, KU Leuven, Celestijnenlaan 200F, Heverlee, Flanders, 3001, Belgium
| | - Caroline Weydert
- Department of Pharmaceutical and Pharmacological Sciences, Laboratory for Molecular Virology and Gene Therapy, KU Leuven, Kapucijnenvoer 33, Leuven, Flanders, 3000, Belgium
| | - Wannes Thys
- Department of Pharmaceutical and Pharmacological Sciences, Laboratory for Molecular Virology and Gene Therapy, KU Leuven, Kapucijnenvoer 33, Leuven, Flanders, 3000, Belgium
| | - Sofie Vets
- Department of Pharmaceutical and Pharmacological Sciences, Laboratory for Molecular Virology and Gene Therapy, KU Leuven, Kapucijnenvoer 33, Leuven, Flanders, 3000, Belgium
| | - Barbara Van Remoortel
- Department of Pharmaceutical and Pharmacological Sciences, Laboratory for Molecular Virology and Gene Therapy, KU Leuven, Kapucijnenvoer 33, Leuven, Flanders, 3000, Belgium
| | - Johan Hofkens
- Laboratory for Photochemistry and Spectroscopy, KU Leuven, Celestijnenlaan 200F, Heverlee, Flanders, 3001, Belgium
| | - Jan De Rijck
- Department of Pharmaceutical and Pharmacological Sciences, Laboratory for Molecular Virology and Gene Therapy, KU Leuven, Kapucijnenvoer 33, Leuven, Flanders, 3000, Belgium
| | - Jelle Hendrix
- Laboratory for Photochemistry and Spectroscopy, KU Leuven, Celestijnenlaan 200F, Heverlee, Flanders, 3001, Belgium
| | - Norbert Bannert
- Robert Koch Institute, Centre for HIV and Retrovirology, Nordufer 20, Berlin, 13353, Germany
| | - Rik Gijsbers
- Department of Pharmaceutical and Pharmacological Sciences, Laboratory for Molecular Virology and Gene Therapy, KU Leuven, Kapucijnenvoer 33, Leuven, Flanders, 3000, Belgium
| | - Frauke Christ
- Department of Pharmaceutical and Pharmacological Sciences, Laboratory for Molecular Virology and Gene Therapy, KU Leuven, Kapucijnenvoer 33, Leuven, Flanders, 3000, Belgium
| | - Zeger Debyser
- Department of Pharmaceutical and Pharmacological Sciences, Laboratory for Molecular Virology and Gene Therapy, KU Leuven, Kapucijnenvoer 33, Leuven, Flanders, 3000, Belgium
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18
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Comprehensive in vitro analysis of simian retrovirus type 4 susceptibility to antiretroviral agents. J Virol 2013; 87:4322-9. [PMID: 23365453 DOI: 10.1128/jvi.03208-12] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Simian retrovirus type 4 (SRV-4), a simian type D retrovirus, naturally infects cynomolgus monkeys, usually without apparent symptoms. However, some infected monkeys presented with an immunosuppressive syndrome resembling that induced by simian immunodeficiency virus infection. Antiretrovirals with inhibitory activity against SRV-4 are considered to be promising agents to combat SRV-4 infection. However, although some antiretrovirals have been reported to have inhibitory activity against SRV-1 and SRV-2, inhibitors with anti-SRV-4 activity have not yet been studied. In this study, we identified antiretroviral agents with anti-SRV-4 activity from a panel of anti-human immunodeficiency virus (HIV) drugs using a robust in vitro luciferase reporter assay. Among these, two HIV reverse transcriptase inhibitors, zidovudine (AZT) and tenofovir disoproxil fumarate (TDF), potently inhibited SRV-4 infection within a submicromolar to nanomolar range, which was similar to or higher than the activities against HIV-1, Moloney murine leukemia virus, and feline immunodeficiency virus. In contrast, nonnucleoside reverse transcriptase inhibitors and protease inhibitors did not exhibit any activities against SRV-4. Although both AZT and TDF effectively inhibited cell-free SRV-4 transmission, they exhibited only partial inhibitory activities against cell-to-cell transmission. Importantly, one HIV integrase strand transfer inhibitor, raltegravir (RAL), potently inhibited single-round infection as well as cell-free and cell-to-cell SRV-4 transmission. These findings indicate that viral expansion routes impact the inhibitory activity of antiretrovirals against SRV-4, while only RAL is effective in suppressing both the initial SRV-4 infection and subsequent SRV-4 replication.
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Kishimoto N, Onitsuka A, Kido K, Takamune N, Shoji S, Misumi S. Glyceraldehyde 3-phosphate dehydrogenase negatively regulates human immunodeficiency virus type 1 infection. Retrovirology 2012; 9:107. [PMID: 23237566 PMCID: PMC3531276 DOI: 10.1186/1742-4690-9-107] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2012] [Accepted: 11/25/2012] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Host proteins are incorporated inside human immunodeficiency virus type 1 (HIV-1) virions during assembly and can either positively or negatively regulate HIV-1 infection. Although the identification efficiency of host proteins is improved by mass spectrometry, how those host proteins affect HIV-1 replication has not yet been fully clarified. RESULTS In this study, we show that virion-associated glyceraldehyde 3-phosphate dehydrogenase (GAPDH) does not allosterically inactivate HIV-1 reverse transcriptase (RT) but decreases the efficiency of reverse transcription reactions by decreasing the packaging efficiency of lysyl-tRNA synthetase (LysRS) and tRNA(Lys3) into HIV-1 virions. Two-dimensional (2D) gel electrophoresis demonstrated that some isozymes of GAPDH with different isoelectric points were expressed in HIV-1-producing CEM/LAV-1 cells, and a proportion of GAPDH was selectively incorporated into the virions. Suppression of GAPDH expression by RNA interference in CEM/LAV-1 cells resulted in decreased GAPDH packaging inside the virions, and the GAPDH-packaging-defective virus maintained at least control levels of viral production but increased the infectivity. Quantitative analysis of reverse transcription products indicated that the levels of early cDNA products of the GAPDH-packaging-defective virus were higher than those of the control virus owing to the higher packaging efficiencies of LysRS and tRNA(Lys3) into the virions rather than the GAPDH-dependent negative allosteric modulation for RT. Furthermore, immunoprecipitation assay using an anti-GAPDH antibody showed that GAPDH directly interacted with Pr55(gag) and p160(gag)-pol and the overexpression of LysRS in HIV-1-producing cells resulted in a decrease in the efficiency of GAPDH packaging in HIV particles. In contrast, the viruses produced from cells expressing a high level of GAPDH showed decreased infectivity in TZM-bl cells and reverse transcription efficiency in TZM-bl cells and peripheral blood mononuclear cells (PBMCs). CONCLUSIONS These findings indicate that GAPDH negatively regulates HIV-1 infection and provide insights into a novel function of GAPDH in the HIV-1 life cycle and a new host defense mechanism against HIV-1 infection.
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Affiliation(s)
- Naoki Kishimoto
- Department of Pharmaceutical Biochemistry, Faculty of Medical and Pharmaceutical Sciences, Kumamoto University, Kumamoto 862-0973, Japan
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Li Z, Wu S, Wang J, Li W, Lin Y, Ji C, Xue J, Chen J. Evaluation of the interactions of HIV-1 integrase with small ubiquitin-like modifiers and their conjugation enzyme Ubc9. Int J Mol Med 2012; 30:1053-60. [PMID: 22895527 DOI: 10.3892/ijmm.2012.1088] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2012] [Accepted: 05/18/2012] [Indexed: 11/06/2022] Open
Abstract
Human immunodeficiency virus type 1 (HIV-1) integrase mediates the integration of reverse-transcribed viral cDNA into the genome of the host for the stable maintenance of the viral genome and the persistence of HIV-1 infection. In this study, the relationships between HIV-1 integrase (HIV-1 IN) and three SUMO conjugation pathway proteins, as well as the effects of these associations, were investigated. The overexpression of SUMO1/SUMO2 and Ubc9 changed the intracellular localization of HIV-1 IN from a diffuse distribution to a punctate localization. SUMO1, SUMO2 and Ubc9 were shown to interact with HIV-1 IN. The SUMOylation of HIV-1 IN was verified. In addition, SUMO1, SUMO2 and Ubc9 were shown to influence the integration of both lentivirus and HIV-1. The overexpression of Ubc9 inhibited viral genome integration, and the upregulation of SUMO1 or SUMO2 enhanced the inhibitory effect of Ubc9. Knockdown of the endogenous levels of SUMO1, SUMO2 and Ubc9 increased the level of viral integration, while reverse transcription and the nuclear import of preintegration complex (PIC) were not affected. Our findings suggest that SUMO conjugation pathway proteins may act as cellular restriction factors and be detrimental to HIV-1 infection. These findings merit further investigation because of their potentially significant implications for the cellular antiviral response to HIV-1 infection.
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Affiliation(s)
- Zhihui Li
- State Key Laboratory of Genetic Engineering, Institute of Genetics, School of Life Sciences, Fudan University, Shanghai 200433, PR China
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21
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Levin A, Hayouka Z, Friedler A, Loyter A. Transportin 3 and importin α are required for effective nuclear import of HIV-1 integrase in virus-infected cells. Nucleus 2012; 1:422-31. [PMID: 21326825 DOI: 10.4161/nucl.1.5.12903] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2010] [Revised: 07/02/2010] [Accepted: 07/07/2010] [Indexed: 01/25/2023] Open
Abstract
Unlike other retroviruses, human immunodeficiency virus type-1 (HIV-1) can infect terminally differentiated cells, due to the ability of its pre-integration complex (PIC) to translocate via the host nuclear pore complex (NPC). The PIC Nuclear import has been suggested to be mediated by the viral integrase protein (IN), via either the importin α or transportin 3 (TNPO3/transportin-SR2) pathways.We show that in virus-infected cells, IN interacts with both importin α and TNPO3, simultaneously or separately, suggesting a multiple use of nuclear import pathways. Disruption of either the IN-importin α or IN-TNPO3 complexes in virus-infected cells by specific cell-permeable-peptides resulted in inhibition of IN and viral cDNA nuclear import. Here we show that peptides which disrupt either one of these complexes block virus infection, indicating involvement of both pathways in efficient viral replication. Formation of IN-importin α and IN-TNPO3 complexes has also been observed in IN-transfected cultured cells. Using specific peptides, we demonstrate that in transfected cells but not in virus infected cells the importin α pathway overrides that of TNPO3. The IN-importin α and IN-TNPO3 complexes were not observed in virus-infected Rev-expressing cells, indicating the Rev protein's ability to disrupt both complexes.Our work suggests that IN nuclear import requires the involvement of both importin α and TNPO3. The ability to inhibit nuclear import of the IN-DNA complex and consequently, virus infection by peptides that interrupt IN's interaction with either importin α or TNPO3 indicates that for efficient infection, nuclear import of IN should be mediated by both nuclear-import receptors.
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Affiliation(s)
- Aviad Levin
- Department of Biological Chemistry, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Safra Campus, Givat Ram, Jerusalem 91904, Israel
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Jayappa KD, Ao Z, Yao X. The HIV-1 passage from cytoplasm to nucleus: the process involving a complex exchange between the components of HIV-1 and cellular machinery to access nucleus and successful integration. INTERNATIONAL JOURNAL OF BIOCHEMISTRY AND MOLECULAR BIOLOGY 2012; 3:70-85. [PMID: 22509482 PMCID: PMC3325773] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 01/09/2012] [Accepted: 02/22/2012] [Indexed: 05/31/2023]
Abstract
The human immunodeficiency virus 1 (HIV-1) synthesizes its genomic DNA in cytoplasm as soon as it enters the cell. The newly synthesized DNA remains associated with viral/cellular proteins as a high molecular weight pre-integration complex (PIC), which precludes passive diffusion across intact nuclear membrane. However, HIV-1 successfully overcomes nuclear membrane barrier by actively delivering its DNA into nucleus with the help of host nuclear import machinery. Such ability allows HIV-1 to productively infect non-dividing cells as well as dividing cells at interphase. Further, HIV-1 nuclear import is also found important for the proper integration of viral DNA. Thus, nuclear import plays a crucial role in establishment of infection and disease progression. While several viral components, including matrix, viral protein R, integrase, capsid, and central DNA flap are implicated in HIV-1 nuclear import, their molecular mechanism remains poorly understood. In this review, we will elaborate the role of individual viral factors and some of current insights on their molecular mechanism(s) associated with HIV-1 nuclear import. In addition, we will discuss the importance of nuclear import for subsequent step of viral DNA integration. Hereby we aim to further our understanding on molecular mechanism of HIV-1 nuclear import and its potential usefulness for anti-HIV-1 strategies.
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Affiliation(s)
- Kallesh Danappa Jayappa
- Laboratory of Molecular Human Retrovirology, Department of Medical Microbiology, Faculty of Medicine, University of Manitoba Winnipeg, MB, Canada
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Ao Z, Jayappa KD, Wang B, Zheng Y, Wang X, Peng J, Yao X. Contribution of host nucleoporin 62 in HIV-1 integrase chromatin association and viral DNA integration. J Biol Chem 2012; 287:10544-10555. [PMID: 22308026 DOI: 10.1074/jbc.m111.317057] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
HIV-1 integration is promoted by viral integrase (IN) and its cellular cofactors. The lens epithelium-derived growth factor (LEDGF/p75), an IN interacting cellular cofactor, has been shown to play an important role in HIV-1 chromatin targeting and integration. However, whether other cellular cofactors are also involved in viral replication steps is still elusive. Here, we show that nucleoporin 62 (Nup62) is a chromatin-bound protein and can specifically interact with HIV-1 IN in both soluble nuclear extract and chromatin-bound fractions. The knockdown of Nup62 by shRNA reduced the association of IN with host chromatin and significantly impaired viral integration and replication in HIV-1-susceptible cells. Furthermore, the expression of the IN-binding region of Nup62 in CD4(+) T cells significantly inhibited HIV-1 infection. Taken together, these results indicate that the cellular Nup62 is specifically recruited by HIV-1 IN and contribute to an efficient viral DNA integration.
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Affiliation(s)
- Zhujun Ao
- Laboratory of Molecular Human Retrovirology, Department of Medical Microbiology, Faculty of Medicine, University of Manitoba, Winnipeg, Manitoba R3E 0J9, Canada
| | - Kallesh Danappa Jayappa
- Laboratory of Molecular Human Retrovirology, Department of Medical Microbiology, Faculty of Medicine, University of Manitoba, Winnipeg, Manitoba R3E 0J9, Canada
| | - Binchen Wang
- Laboratory of Molecular Human Retrovirology, Department of Medical Microbiology, Faculty of Medicine, University of Manitoba, Winnipeg, Manitoba R3E 0J9, Canada
| | - Yingfeng Zheng
- Laboratory of Molecular Human Retrovirology, Department of Medical Microbiology, Faculty of Medicine, University of Manitoba, Winnipeg, Manitoba R3E 0J9, Canada
| | - Xiaoxia Wang
- Laboratory of Molecular Human Retrovirology, Department of Medical Microbiology, Faculty of Medicine, University of Manitoba, Winnipeg, Manitoba R3E 0J9, Canada
| | - Jinyu Peng
- Laboratory of Molecular Human Retrovirology, Department of Medical Microbiology, Faculty of Medicine, University of Manitoba, Winnipeg, Manitoba R3E 0J9, Canada
| | - Xiaojian Yao
- Laboratory of Molecular Human Retrovirology, Department of Medical Microbiology, Faculty of Medicine, University of Manitoba, Winnipeg, Manitoba R3E 0J9, Canada.
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Correlation of recombinant integrase activity and functional preintegration complex formation during acute infection by replication-defective integrase mutant human immunodeficiency virus. J Virol 2012; 86:3861-79. [PMID: 22278243 DOI: 10.1128/jvi.06386-11] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Previous studies characterized two types of replication-defective human immunodeficiency virus type 1 (HIV-1) integrase mutants: class I, which are specifically blocked at the integration step, and class II, which harbor additional virion production and/or reverse transcription defects. Class I mutant enzymes supported little if any metal ion-dependent 3'-processing and DNA strand transfer activities in vitro, whereas class II enzymes displayed partial or full catalytic function in studies with simplified assay designs, suggesting that defective interaction(s) with heterologous integrase binding proteins might underlie the class II mutant viral phenotype. To address this hypothesis, class I and II mutant enzymes were interrogated under expanded sets of in vitro conditions. The majority failed to catalyze the concerted integration of two viral DNA ends into target DNA, highlighting defective integrase function as the root cause of most class II in addition to all class I mutant virus infection defects. One mutant protein, K264E, in contrast, could support the wild-type level of concerted integration activity. After accounting for its inherent reverse transcription defect, HIV-1(K264E) moreover formed preintegration complexes that supported the efficient integration of endogenous viral DNA in vitro and normal levels and sequences of 2-long terminal repeat-containing circle junctions during acute infection. K264E integrase furthermore efficiently interacted in vitro with two heterologous binding partners, LEDGF/p75 and reverse transcriptase. Our results underscore the physiological relevance of concerted integration assays for tests of integrase mutant function and suggest that the K264E mutation disrupts an interaction with an intranuclear integrase binding partner that is important for HIV-1 integration.
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Masuda T. Non-Enzymatic Functions of Retroviral Integrase: The Next Target for Novel Anti-HIV Drug Development. Front Microbiol 2011; 2:210. [PMID: 22016749 PMCID: PMC3192317 DOI: 10.3389/fmicb.2011.00210] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2011] [Accepted: 09/26/2011] [Indexed: 01/01/2023] Open
Abstract
Integrase (IN) is a retroviral enzyme that catalyzes the insertion of viral DNA (vDNA) into host chromosomal DNA, which is necessary for efficient viral replication. The crystal structure of prototype foamy virus IN bound to cognate vDNA ends, a complex referred to as the intasome, has recently been resolved. Structure analysis of the intasome revealed a tetramer structure of IN that was required for its catalytic function, and also showed the inhibitory mechanism of the IN inhibitor. Genetic analysis of IN has revealed additional non-enzymatic roles during viral replication cycles at several steps other than integration. However, the higher order structure of IN that is required for its non-enzymatic functions remains to be delineated. This is the next major challenge in the field of IN structural biology hoping to be a platform for the development of novel IN inhibitors to treat human immunodeficiency virus type 1 infectious disease.
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Affiliation(s)
- Takao Masuda
- Department of Immunotherapeutics, Tokyo Medical and Dental University Tokyo, Japan
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26
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[Viral and host factors affecting efficient revere transcription of HIV-1 genome]. Uirusu 2011; 61:73-80. [PMID: 21972558 DOI: 10.2222/jsv.61.73] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
Reverse transcription of retroviral RNA into double stranded DNA is a characteristic feature of rertoviruses including human immunodeficiency virus type I (HIV-1). There has been accumulating evidence for the involvement of retroviral integrase (IN) in the reverse transcription of viral RNA. Here, we summarized recent our studies demonstrating direct functional roles of IN and its binding partner of host factor, Gemin2 in the reverse transcription. We established new in vitro cell-free assay to mimic natural reverse transcription and found that HIV-1 IN and host factor, Gemin2 synergistically stimulate reverse transcriptase (RT) activity. Analysis of intracellular stability and multimer formation of IN suggest that that high-ordered structures, especially tetramer formation of IN is critical for the function. In addition, Gemin2 might have a role to keep the higher-order structure of IN. Thus, we provide new aspects of reverse transcription of HIV-1 through IN and host factors in addition to RT.
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Zamborlini A, Coiffic A, Beauclair G, Delelis O, Paris J, Koh Y, Magne F, Giron ML, Tobaly-Tapiero J, Deprez E, Emiliani S, Engelman A, de Thé H, Saïb A. Impairment of human immunodeficiency virus type-1 integrase SUMOylation correlates with an early replication defect. J Biol Chem 2011; 286:21013-22. [PMID: 21454548 PMCID: PMC3121452 DOI: 10.1074/jbc.m110.189274] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2010] [Revised: 02/23/2011] [Indexed: 11/06/2022] Open
Abstract
HIV-1 integrase (IN) orchestrates the integration of the reverse transcribed viral cDNA into the host cell genome and participates also in other steps of HIV-1 replication. Cellular and viral factors assist IN in performing its multiple functions, and post-translational modifications contribute to modulate its activities. Here, we show that HIV-1 IN is modified by SUMO proteins and that phylogenetically conserved SUMOylation consensus motifs represent major SUMO acceptor sites. Viruses harboring SUMOylation site IN mutants displayed a replication defect that was mapped during the early stages of infection, before integration but after reverse transcription. Because SUMOylation-defective IN mutants retained WT catalytic activity, we hypothesize that SUMOylation might regulate the affinity of IN for co-factors, contributing to efficient HIV-1 replication.
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Affiliation(s)
- Alessia Zamborlini
- From the CNRS UMR7212, INSERM U944, Institut Universitaire d'Hématologie-Université Paris7 Diderot, 75475 Paris, France
- the Conservatoire des Arts et Métiers, Paris, France
| | - Audrey Coiffic
- From the CNRS UMR7212, INSERM U944, Institut Universitaire d'Hématologie-Université Paris7 Diderot, 75475 Paris, France
| | - Guillaume Beauclair
- From the CNRS UMR7212, INSERM U944, Institut Universitaire d'Hématologie-Université Paris7 Diderot, 75475 Paris, France
| | - Olivier Delelis
- Laboratoire de Biotechnologies et Pharmacologie Génétique Appliquée, CNRS UMR8113, Ecole Normale Supérieure, 94235 Cachan, France
| | - Joris Paris
- From the CNRS UMR7212, INSERM U944, Institut Universitaire d'Hématologie-Université Paris7 Diderot, 75475 Paris, France
| | - Yashuiro Koh
- the Department of Cancer Immunology and AIDS, Dana-Farber Cancer Institute, Boston, Massachusetts 02215
| | - Fabian Magne
- From the CNRS UMR7212, INSERM U944, Institut Universitaire d'Hématologie-Université Paris7 Diderot, 75475 Paris, France
- the Conservatoire des Arts et Métiers, Paris, France
| | - Marie-Lou Giron
- From the CNRS UMR7212, INSERM U944, Institut Universitaire d'Hématologie-Université Paris7 Diderot, 75475 Paris, France
| | - Joelle Tobaly-Tapiero
- From the CNRS UMR7212, INSERM U944, Institut Universitaire d'Hématologie-Université Paris7 Diderot, 75475 Paris, France
| | - Eric Deprez
- Laboratoire de Biotechnologies et Pharmacologie Génétique Appliquée, CNRS UMR8113, Ecole Normale Supérieure, 94235 Cachan, France
| | - Stephane Emiliani
- INSERM U1016, CNRS UMR8104, Université Paris Descartes, Institut Cochin, 75014 Paris, France, and
| | - Alan Engelman
- the Department of Cancer Immunology and AIDS, Dana-Farber Cancer Institute, Boston, Massachusetts 02215
| | - Hugues de Thé
- From the CNRS UMR7212, INSERM U944, Institut Universitaire d'Hématologie-Université Paris7 Diderot, 75475 Paris, France
| | - Ali Saïb
- From the CNRS UMR7212, INSERM U944, Institut Universitaire d'Hématologie-Université Paris7 Diderot, 75475 Paris, France
- the Conservatoire des Arts et Métiers, Paris, France
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The 156KELK159 tetrapeptide of HIV-1 integrase is critical for lentiviral gene integration. Mol Biol Rep 2011; 39:343-9. [PMID: 21556766 DOI: 10.1007/s11033-011-0744-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2009] [Accepted: 04/27/2011] [Indexed: 10/18/2022]
Abstract
HIV-1 integrase (HIV-1 IN), a key element of HIV-1-derived lentiviral vectors, is crucial for the stable maintenance of the vector gene by inserting them into host genome. HIV-1 IN has been found to have functions other than integration, such as involving in virion morphology, viral DNA synthesis and viral DNA nuclear import. In our study, the yeast two-hybrid assay identified a tetrapeptide 156KELK159 in HIV-1 IN that was crucial for HIV-1 IN and Daxx interaction. To investigate the functions of the tetrapeptide 156KELK159 of the HIV-1 IN, both the wild type HIV-1 IN and a mutant without 156KELK159 were used to package the EGFP reporter gene contained lentivirus. p24 based titer assay revealed that deleting the tetrapeptide did not affect virus packaging. The result was verified by quantitative real time PCR with viral specific primers. But the 156KELK159 was crucial for lentiviral gene integration. Deleting the tetrapeptide made the percentage of cells expressing the reporter gene significantly decreased and did not affect the level of DNA entered into the cells or nucleus. Real time reverse transcription PCR and FACS were used to detect the lentiviral report gene expression in infection maintaining cells and revealed 156KELK159 did not affect lentiviral vector gene expression. Our results may shed light on the regulatory mechanism of gene integration of lentivirus.
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Cohen S, Au S, Panté N. How viruses access the nucleus. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2010; 1813:1634-45. [PMID: 21167871 DOI: 10.1016/j.bbamcr.2010.12.009] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2010] [Revised: 11/24/2010] [Accepted: 12/08/2010] [Indexed: 10/25/2022]
Abstract
Many viruses depend on nuclear proteins for replication. Therefore, their viral genome must enter the nucleus of the host cell. In this review we briefly summarize the principles of nucleocytoplasmic transport, and then describe the diverse strategies used by viruses to deliver their genomes into the host nucleus. Some of the emerging mechanisms include: (1) nuclear entry during mitosis, when the nuclear envelope is disassembled, (2) viral genome release in the cytoplasm followed by entry of the genome through the nuclear pore complex (NPC), (3) capsid docking at the cytoplasmic side of the NPC, followed by genome release, (4) nuclear entry of intact capsids through the NPC, followed by genome release, and (5) nuclear entry via virus-induced disruption of the nuclear envelope. Which mechanism a particular virus uses depends on the size and structure of the virus, as well as the cellular cues used by the virus to trigger capsid disassembly and genome release. This article is part of a Special Issue entitled: Regulation of Signaling and Cellular Fate through Modulation of Nuclear Protein Import.
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Affiliation(s)
- Sarah Cohen
- Department of Zoology, University of British Columbia, 6270 University Boulevard, Vancouver, British Columbia, Canada
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Hayashi T, Nishitsuji H, Takamori A, Hasegawa A, Masuda T, Kannagi M. DNA-dependent activator of IFN-regulatory factors enhances the transcription of HIV-1 through NF-κB. Microbes Infect 2010; 12:937-47. [DOI: 10.1016/j.micinf.2010.06.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2010] [Revised: 06/10/2010] [Accepted: 06/11/2010] [Indexed: 12/21/2022]
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Ahmed N, Hayashi T, Hasegawa A, Furukawa H, Okamura N, Chida T, Masuda T, Kannagi M. Suppression of human immunodeficiency virus type 1 replication in macrophages by commensal bacteria preferentially stimulating Toll-like receptor 4. J Gen Virol 2010; 91:2804-13. [PMID: 20719993 DOI: 10.1099/vir.0.022442-0] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Protection from primary human immunodeficiency virus type 1 (HIV-1) infection has not yet been accomplished by vaccines inducing HIV-1-specific acquired immunity. Nevertheless, it has been reported that a small subgroup of women remain resistant to HIV-1 infection under natural conditions. If similar conditions can be induced in uninfected individuals, it will contribute the first line of protection against HIV-1 infection, and also improve the effects of anti-HIV-1 vaccines. We reasoned that innate immunity may be involved in the resistance to HIV-1 infection, and investigated the effects of various Toll-like receptor (TLR) ligands and commensal bacteria on HIV-1 replication in macrophages, one of the initial targets of HIV-1 infection and also the main mediators of innate immunity. We established the HIV-1 reporter monocytic cell line, THP-1/NL4-3luc, which could be differentiated into macrophage-like cells in vitro. In these cells, stimulation of TLR3 and TLR4 by their ligands suppressed HIV-1 expression partly through type I interferon (IFN). Among the commensal bacteria tested, Escherichia coli, Veillonella parvula and Neisseria mucosa suppressed HIV-1 expression, whereas Lactobacillus acidophilus, Prevotella melaninogenica, P. bivia and Mycobacterium smegmatis enhanced it. The bacteria with suppressive effects preferentially stimulated TLR4, whereas the ones with enhancing effects stimulated TLR2. Neutralizing antibodies against TLR4 and IFN-α/β receptor abrogated bacterially mediated HIV-1 suppression. Suppressive effects of E. coli, V. parvula and N. mucosa on HIV-1 replication were reproducible in primary monocyte-derived macrophages following acute HIV-1 infection. These findings suggest that certain commensal bacteria preferentially stimulating TLR4 potentially produce local environments resistant to HIV-1 infection.
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Affiliation(s)
- Nursarat Ahmed
- Department of Immunotherapeutics, Graduate School, Tokyo Medical and Dental University, Tokyo, Japan
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Misumi S, Inoue M, Dochi T, Kishimoto N, Hasegawa N, Takamune N, Shoji S. Uncoating of human immunodeficiency virus type 1 requires prolyl isomerase Pin1. J Biol Chem 2010; 285:25185-95. [PMID: 20529865 PMCID: PMC2919081 DOI: 10.1074/jbc.m110.114256] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The process by which the human immunodeficiency virus type 1 (HIV-1) conical core dissociates is called uncoating, but not much is known about this process. Here, we show that the uncoating process requires the interaction of the capsid (CA) protein with the peptidyl-prolyl isomerase Pin1 that specifically recognizes the phosphorylated serine/threonine residue followed by proline. We found that the HIV-1 core is composed of some isoforms of the CA protein with different isoelectric points, and one isoform is preferentially phosphorylated in the Ser16-Pro17 motif. The mutant virus S16A/P17A shows a severely attenuated HIV-1 replication and an impaired reverse transcription. The S16A/P17A change increased the amount of particulate CA cores in the cytosol of target cells and correlated with the restriction of HIV-1 infection. Glutathione S-transferase pulldown assays demonstrated a direct interaction between Pin1 and the HIV-1 core via the Ser16-Pro17 motif. Suppression of Pin1 expression by RNA interference in a target cell results in an attenuated HIV-1 replication and increases the amount of particulate CA cores in the cytosol of target cells. Furthermore, heat-inactivated, inhibitor-treated, or W34A/K63A Pin1 causes an attenuated in vitro uncoating of the HIV-1 core. The Pin1-dependent uncoating is inhibited by antisera raised against a CA peptide phosphorylated at Ser16 or treatment of the HIV-1 core with alkaline phosphatase. These findings provide insights into this obscure uncoating process in the HIV-1 life cycle and a new cellular target for HIV-1 drug development.
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Affiliation(s)
- Shogo Misumi
- Department of Pharmaceutical Biochemistry, Faculty of Medical and Pharmaceutical Sciences, Kumamoto University, Kumamoto 862-0973, Japan.
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Levin A, Hayouka Z, Friedler A, Loyter A. Nucleocytoplasmic shuttling of HIV-1 integrase is controlled by the viral Rev protein. Nucleus 2010; 1:190-201. [PMID: 21326951 PMCID: PMC3030695 DOI: 10.4161/nucl.1.2.11300] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2009] [Revised: 01/13/2010] [Accepted: 01/14/2010] [Indexed: 01/21/2023] Open
Abstract
In the current study we show that the Rev protein of Human Immunodeficiency Virus type 1 (HIV-1) inhibits nuclear import and mediates nuclear export of the HIV-1 integrase (IN) protein, which catalyzes integration of the viral cDNA. Interaction between IN and Rev in virus infected cells, resulting in the formation of a Rev-IN complex, has been previously described by us. Here we show that nuclear import of the IN, is inhibited by early expressed Rev. No nuclear import of IN was observed when Rev-overexpressing cells were infected by wild-type HIV-1. Similarly, no translocation of IN into nuclei was observed in the presence of Rev-derived peptides. On the other hand, massive nuclear import was observed following infection by a ΔRev virus or in the presence of peptides that promote dissociation of the Rev-IN complex. Our results show that IN is only transiently present within the nuclei of infected cells. Treatment of infected cells with leptomycin B caused nuclear retention of the Rev-IN complex. Removal of the leptomycin from these treated cells resulted in nuclear export of both Rev and IN. On the other hand, disruption of the nuclear located Rev-IN complex resulted in export of only the Rev protein indicating Rev-mediated nuclear export of IN. Our results suggest the involvement of Rev in regulating the integration process by limiting the number of integration events per cell despite the presence of numerous copies of viral cDNA.
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Affiliation(s)
- Aviad Levin
- Department of Biological Chemistry; The Alexander Silberman Institute of Life Sciences
| | - Zvi Hayouka
- Institute of Chemistry; The Hebrew University of Jerusalem; Jerusalem, Israel
| | - Assaf Friedler
- Institute of Chemistry; The Hebrew University of Jerusalem; Jerusalem, Israel
| | - Abraham Loyter
- Department of Biological Chemistry; The Alexander Silberman Institute of Life Sciences
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Nishitsuji H, Hayashi T, Takahashi T, Miyano M, Kannagi M, Masuda T. Augmentation of reverse transcription by integrase through an interaction with host factor, SIP1/Gemin2 Is critical for HIV-1 infection. PLoS One 2009; 4:e7825. [PMID: 19915660 PMCID: PMC2771899 DOI: 10.1371/journal.pone.0007825] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2009] [Accepted: 10/16/2009] [Indexed: 11/23/2022] Open
Abstract
There has been accumulating evidence for the involvement of retroviral integrase (IN) in the reverse transcription of viral RNA. We previously identified a host factor, survival motor neuron-interacting protein 1 (SIP1/Gemin2) that binds to human immunodeficiency virus type 1 (HIV-1) IN and supports HIV-1 infection apparently at reverse transcription step. Here, we demonstrated that HIV-1 IN together with SIP1 augments reverse transcriptase (RT) activity by enhancing the assembly of RT on viral RNA in vitro. Synthetic peptides corresponding to the binding motifs within IN that inhibited the IN-SIP1 interaction abrogated reverse transcription in vitro and in vivo. Furthermore, knockdown of SIP1 reduced intracellular stability and multimer formation of IN through proteasome-mediated degradation machinery. Taken together, SIP1 appears to stabilize functional multimer forms of IN, thereby promoting the assembly of IN and RT on viral RNA to allow efficient reverse transcription, which is a prerequisite for efficient HIV-1 infection.
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Affiliation(s)
- Hironori Nishitsuji
- Department of Immunotherapeutics, Graduate School of Medicine and Dentistry, Tokyo Medical and Dental University, Tokyo, Japan
| | - Takaya Hayashi
- Department of Immunotherapeutics, Graduate School of Medicine and Dentistry, Tokyo Medical and Dental University, Tokyo, Japan
| | - Takuya Takahashi
- Department of Immunotherapeutics, Graduate School of Medicine and Dentistry, Tokyo Medical and Dental University, Tokyo, Japan
| | - Masashi Miyano
- Department of Immunotherapeutics, Graduate School of Medicine and Dentistry, Tokyo Medical and Dental University, Tokyo, Japan
| | - Mari Kannagi
- Department of Immunotherapeutics, Graduate School of Medicine and Dentistry, Tokyo Medical and Dental University, Tokyo, Japan
| | - Takao Masuda
- Department of Immunotherapeutics, Graduate School of Medicine and Dentistry, Tokyo Medical and Dental University, Tokyo, Japan
- * E-mail:
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Abstract
HIV-1 possesses an exquisite ability to infect cells independently from their cycling status by undergoing an active phase of nuclear import through the nuclear pore. This property has been ascribed to the presence of karyophilic elements present in viral nucleoprotein complexes, such as the matrix protein (MA); Vpr; the integrase (IN); and a cis-acting structure present in the newly synthesized DNA, the DNA flap. However, their role in nuclear import remains controversial at best. In the present study, we carried out a comprehensive analysis of the role of these elements in nuclear import in a comparison between several primary cell types, including stimulated lymphocytes, macrophages, and dendritic cells. We show that despite the fact that none of these elements is absolutely required for nuclear import, disruption of the central polypurine tract-central termination sequence (cPPT-CTS) clearly affects the kinetics of viral DNA entry into the nucleus. This effect is independent of the cell cycle status of the target cells and is observed in cycling as well as in nondividing primary cells, suggesting that nuclear import of viral DNA may occur similarly under both conditions. Nonetheless, this study indicates that other components are utilized along with the cPPT-CTS for an efficient entry of viral DNA into the nucleus.
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Integrase interacts with nucleoporin NUP153 to mediate the nuclear import of human immunodeficiency virus type 1. J Virol 2009; 83:6522-33. [PMID: 19369352 DOI: 10.1128/jvi.02061-08] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The ability to traverse an intact nuclear envelope and productively infect nondividing cells is a salient feature of human immunodeficiency virus type 1 (HIV-1) and other lentiviruses, but the viral factors and mechanism of nuclear entry have not been defined. HIV-1 integrase (IN) is implicated to play a role in the nuclear import of the virus, but the cellular pathway for IN trafficking and the role of IN in mediating the nuclear import of viral particles are unknown. Using a semipermeabilized cell assay, we observed that the nuclear import of IN was not the result of passive diffusion but occurred independently of cytosolic factors, metabolic energy, and the classical receptor-mediated, Ran-dependent import pathways. To determine if IN enters the nucleus by interacting with the nucleopore complex (NPC), we found that IN bound directly with the FxFG-rich C-terminal domain of nucleoporin 153 (NUP153C). When added in excess to the import assay, NUP153C inhibited the nuclear import of IN. Known binding partners of NUP153C competed with IN for binding with NUP153 and also inhibited the nuclear import of IN. In cultured cells, overexpression of NUP153C reduced the infectivity of an HIV-derived vector by interfering with the nuclear translocation of the viral cDNA. These results support a functional role for the IN-NUP153 interaction in HIV-1 replication and suggest that HIV-1 subviral particles gain access to the nucleus by interacting directly with the NPC via the binding of particle-associated IN to NUP153C.
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Xu Z, Zheng Y, Ao Z, Clement M, Mouland AJ, Kalpana GV, Belhumeur P, Cohen EA, Yao X. Contribution of the C-terminal region within the catalytic core domain of HIV-1 integrase to yeast lethality, chromatin binding and viral replication. Retrovirology 2008; 5:102. [PMID: 19014595 PMCID: PMC2615443 DOI: 10.1186/1742-4690-5-102] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2008] [Accepted: 11/14/2008] [Indexed: 11/29/2022] Open
Abstract
Background HIV-1 integrase (IN) is a key viral enzymatic molecule required for the integration of the viral cDNA into the genome. Additionally, HIV-1 IN has been shown to play important roles in several other steps during the viral life cycle, including reverse transcription, nuclear import and chromatin targeting. Interestingly, previous studies have demonstrated that the expression of HIV-1 IN induces the lethal phenotype in some strains of Saccharomyces cerevisiae. In this study, we performed mutagenic analyses of the C-terminal region of the catalytic core domain of HIV-1 IN in order to delineate the critical amino acid(s) and/or motif(s) required for the induction of the lethal phenotype in the yeast strain HP16, and to further elucidate the molecular mechanism which causes this phenotype. Results Our study identified three HIV-1 IN mutants, V165A, A179P and KR186,7AA, located in the C-terminal region of the catalytic core domain of IN that do not induce the lethal phenotype in yeast. Chromatin binding assays in yeast and mammalian cells demonstrated that these IN mutants were impaired for the ability to bind chromatin. Additionally, we determined that while these IN mutants failed to interact with LEDGF/p75, they retained the ability to bind Integrase interactor 1. Furthermore, we observed that VSV-G-pseudotyped HIV-1 containing these IN mutants was unable to replicate in the C8166 T cell line and this defect was partially rescued by complementation with the catalytically inactive D64E IN mutant. Conclusion Overall, this study demonstrates that three mutations located in the C-terminal region of the catalytic core domain of HIV-1 IN inhibit the IN-induced lethal phenotype in yeast by inhibiting the binding of IN to the host chromatin. These results demonstrate that the C-terminal region of the catalytic core domain of HIV-1 IN is important for binding to host chromatin and is crucial for both viral replication and the promotion of the IN-induced lethal phenotype in yeast.
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Affiliation(s)
- Zaikun Xu
- Laboratory of Molecular Human Retrovirology, Department of Medical Microbiology, University of Manitoba, 508-730 William Avenue, Winnipeg, R3E 0W3, Canada.
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HIV‐1 Integrase Inhibitors: Update and Perspectives. HIV-1: MOLECULAR BIOLOGY AND PATHOGENESIS 2008; 56:199-228. [DOI: 10.1016/s1054-3589(07)56007-2] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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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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De Rijck J, Vandekerckhove L, Christ F, Debyser Z. Lentiviral nuclear import: a complex interplay between virus and host. Bioessays 2007; 29:441-51. [PMID: 17450594 DOI: 10.1002/bies.20561] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Although the capacity to infect non-dividing cells is a hallmark of lentiviruses, nuclear import is still barely understood. More than 100 research papers have been dedicated to this topic during the last 15 years, yet, more questions have been raised than answers. The signal-facilitating translocation of the viral preintegration complex (PIC) through the nuclear pore complex (NPC) remains unknown. It is clear, however, that nuclear import is the result of a complex interplay between viral and cellular components. In this review, we discuss the current knowledge on nuclear import. We focus on the controversies and pitfalls and discuss the interplay between virus and host.
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Affiliation(s)
- Jan De Rijck
- Laboratory for Molecular Virology and Gene Therapy, KULeuven and IRC KULAK, Leuven, Belgium
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42
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Sakuragi JI, Sakuragi S, Shioda T. Minimal region sufficient for genome dimerization in the human immunodeficiency virus type 1 virion and its potential roles in the early stages of viral replication. J Virol 2007; 81:7985-92. [PMID: 17507464 PMCID: PMC1951301 DOI: 10.1128/jvi.00429-07] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
It has been suggested that the dimer initiation site/dimer linkage sequence (DIS/DLS) region of the human immunodeficiency virus type 1 (HIV-1) RNA genome plays an important role at various stages of the viral life cycle. Recently we found that the duplication of the DIS/DLS region on viral RNA caused the production of partially monomeric RNAs in virions, indicating that this region indeed mediates RNA-RNA interaction. In this report, we followed up on this finding to identify the necessary and sufficient region for RNA dimerization in the virion of HIV-1. The region thus identified was 144 bases in length, extending from the junction of R/U5 and U5/L stem-loops to the end of SL4. The trans-acting responsive element, polyadenylation signal, primer binding site, upper stem-loop of U5/L, and SL2 were not needed for the function of this region. The insertion of this region into the ectopic location of the viral genome did not affect the level of virion production by transfection. However, the resultant virions contained monomerized genomes and showed drastic reductions in infectivity. A reduction was observed especially in the reverse transcription process. An attempt to generate a replication-competent virus with monomerized genome was performed by the long-term culture of mutant virus-infected cells. All recovered viruses were wild-type revertants, indicating a fatal defect of the mutation. These results suggest that genome dimerization or DIS/DLS itself also plays an important role in the early stages of virus infection.
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Affiliation(s)
- Jun-Ichi Sakuragi
- Department of Viral Infections, Research Institute for Microbial Diseases, Osaka University, 3-1 Yamadaoka, Suita City, Osaka 565-0871, Japan.
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Ao Z, Huang G, Yao H, Xu Z, Labine M, Cochrane AW, Yao X. Interaction of human immunodeficiency virus type 1 integrase with cellular nuclear import receptor importin 7 and its impact on viral replication. J Biol Chem 2007; 282:13456-67. [PMID: 17360709 DOI: 10.1074/jbc.m610546200] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Similar to all other viruses, human immunodeficiency virus type 1 (HIV-1) depends heavily on cellular factors for its successful replication. In this study we have investigated the interaction of HIV-1 integrase (IN) with several host nuclear import factors using co-immunoprecipitation assays. Our results indicate that IN interacts specifically with host importin 7 (Imp7) in vivo, but does not interact with importin 8 (Imp8) or importin alpha (Rch1). In contrast, another HIV-1 karyophilic protein MAp17, which is capable of binding Rch1, fails to interact with Imp7, suggesting that IN and Map17 may interact with different cellular pathways during HIV-1 replication. Genetic analysis revealed that the C-terminal domain of IN is the region responsible for interaction between IN with Imp7, and an IN mutant (K240A,K244A/R263A,K264A) disrupted the Imp7 binding ability of the protein, indicating that both regions ((235)WKGPAKLLWKG and (262)RRKAK) within the C-terminal domain of IN are required for efficient IN/Imp7 interaction. Using a vesicular stomatitis virus G glycoprotein pseudotyped HIV single-cycle replication system, we showed that the IN/Imp7 interaction-deficient mutant was unable to mediate viral replication and displayed impairment at both viral reverse transcription and nuclear import steps. Moreover, transient knockdown of Imp7 in both HIV-1 producing and target cells resulted in a 2.5-3.5-fold inhibition of HIV infection. Altogether, our results indicate that HIV-1 IN specifically interacts with Imp7, and this viral/cellular protein interaction contributes to efficient HIV-1 infection.
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Affiliation(s)
- Zhujun Ao
- Laboratory of Molecular Human Retrovirology, Department of Medical Microbiology, Faculty of Medicine, University of Manitoba, Winnipeg, Manitoba, R3E 0W3
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Abstract
Human immunodeficiency virus 1 (HIV-1) and other retroviruses synthesize a DNA copy of their genome after entry into the host cell. Integration of this DNA into the host cell's genome is an essential step in the viral replication cycle. The viral DNA is synthesized in the cytoplasm and is associated with viral and cellular proteins in a large nucleoprotein complex. Before integration into the host genome can occur, this complex must be transported to the nucleus and must cross the nuclear envelope. This Review summarizes our current knowledge of how this journey is accomplished.
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Affiliation(s)
- Youichi Suzuki
- Laboratory for Host Factors, Center for Emerging Virus Research, Institute for Virus Research, Kyoto University, 53 Shogoin-Kawara-cho, Sakyo-ku, Kyoto 606-8507, Japan
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Ohishi M, Shioda T, Sakuragi JI. Retro-transduction by virus pseudotyped with glycoprotein of vesicular stomatitis virus. Virology 2007; 362:131-8. [PMID: 17258261 DOI: 10.1016/j.virol.2006.12.030] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2006] [Revised: 12/26/2006] [Accepted: 12/27/2006] [Indexed: 10/23/2022]
Abstract
A virus pseudotyped with glycoprotein of vesicular stomatitis virus (VSV-G) can enter various cell types at a relatively high titer. We observed that the amount of viral antigen from VSV-G pseudotyped human immunodeficiency virus type 1 (HIV-1) producing cells was much higher than that from their non-pseudotyped counterparts. This enhanced viral antigen production was not observed when we used HIV-1 pol mutant, viral enzyme inhibitors, HIV Env protein, or VSV-G fusion defective mutants. The transfection experiment using GFP-expressing virus showed time-dependent expansion of GFP-positive cells and viral DNA integration. These results suggested that the increase in viral antigen yield was caused by the release of a progeny virus following retro-transduction by the pseudotyped virus of the cells within the transfected cell culture. The infectivity as well as the amount of VSV-G on virus particles per unit of viral antigen was significantly different before and after the onset of the yield enhancement. This suggests that results of infection assays of the virus pseudotyped with VSV-G may be affected by the occurrence of such enhancement. This means that, while pseudotyping with VSV-G is a simple and effective method, this procedure should be carefully considered when the virus is produced for infectivity assays.
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Affiliation(s)
- Masahisa Ohishi
- Department of Viral Infections, Research Institute for Microbial Diseases, Osaka University, 3-1 Yamadaoka, Suita City, Osaka 565-0871, Japan
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Fassati A. HIV infection of non-dividing cells: a divisive problem. Retrovirology 2006; 3:74. [PMID: 17067381 PMCID: PMC1635064 DOI: 10.1186/1742-4690-3-74] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2006] [Accepted: 10/26/2006] [Indexed: 02/07/2023] Open
Abstract
Understanding how lentiviruses can infect terminally differentiated, non-dividing cells has proven a very complex and controversial problem. It is, however, a problem worth investigating, for it is central to HIV-1 transmission and AIDS pathogenesis. Here I shall attempt to summarise what is our current understanding for HIV-1 infection of non-dividing cells. In some cases I shall also attempt to make sense of controversies in the field and advance one or two modest proposals.
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Affiliation(s)
- Ariberto Fassati
- Wohl Virion Centre and MRC-UCL Centre for Medical Molecular Virology, Division of Infection and Immunity, University College London, 46 Cleveland Street, London W1T 4JF, UK.
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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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Nishitsuji H, Kohara M, Kannagi M, Masuda T. Effective suppression of human immunodeficiency virus type 1 through a combination of short- or long-hairpin RNAs targeting essential sequences for retroviral integration. J Virol 2006; 80:7658-66. [PMID: 16840344 PMCID: PMC1563699 DOI: 10.1128/jvi.00078-06] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Small interfering RNA (siRNA) could provide a new therapeutic approach to treating human immunodeficiency virus type 1 (HIV-1) infection. For long-term suppression of HIV-1, emergence of siRNA escape variants must be controlled. Here, we constructed lentiviral vectors encoding short-hairpin RNAs (shRNA) corresponding to conserved target sequences within the integrase (int) and the attachment site (att) genes, both of which are essential for HIV-1 integration. Compared to shRNA targeting of the HIV-1 transcription factor tat (shTat), shRNA against int (shIN) or the U3 region of att (shU3) showed a more potent inhibitory effect on HIV-1 replication in human CD4+ T cells. Infection with a high dose of HIV-1 resulted in the emergence of escape mutants during long-term culture. Of note, limited genetic variation was observed in the viruses resistant to shIN. A combination of shINs against wild-type and escape mutant sequences had a negative effect on their antiviral activities, indicating a potentially detrimental effect when administering multiple shRNA targeting the same region to combat HIV-1 variants. The combination of shIN and shU3 att exhibited the strongest anti-HIV-1 activity, as seen by complete abrogation of viral DNA synthesis and viral integration. In addition, a modified long-hairpin RNA spanning the 50 nucleotides in the shIN target region effectively suppressed wild-type and shIN-resistant mutant HIV-1. These results suggest that targeting of incoming viral RNA before proviral DNA formation occurs through the use of nonoverlapping multiple siRNAs is a potent approach to achieving sustained, efficient suppression of highly mutable viruses, such as HIV-1.
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Affiliation(s)
- Hironori Nishitsuji
- 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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Hamamoto S, Nishitsuji H, Amagasa T, Kannagi M, Masuda T. Identification of a novel human immunodeficiency virus type 1 integrase interactor, Gemin2, that facilitates efficient viral cDNA synthesis in vivo. J Virol 2006; 80:5670-7. [PMID: 16731905 PMCID: PMC1472599 DOI: 10.1128/jvi.02471-05] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Retroviral integrase (IN) catalyzes the integration of viral cDNA into a host chromosome. Additional roles have been suggested for IN, including uncoating, reverse transcription, and nuclear import of the human immunodeficiency virus type 1 (HIV-1) genome. However, the underlying mechanism is largely unknown. Here, using a yeast two-hybrid system, we identified a survival motor neuron (SMN)-interacting protein 1 (Gemin2) that binds to HIV-1 IN. Reduction of Gemin2 with small interfering RNA duplexes (siGemin2) dramatically reduced HIV-1 infection in human primary monocyte-derived macrophages and also reduced viral cDNA synthesis. In contrast, siGemin2 did not affect HIV-1 expression from the integrated proviral DNA. Although Gemin2 was undetectable in cell-free viral particles, coimmunoprecipitation experiments using FLAG-tagged Gemin2 strongly suggested that Gemin2 interacts with the incoming viral genome through IN. Further experiments reducing SMN or other SMN-interacting proteins suggested that Gemin2 might act on HIV-1 either alone or with unknown proteins to facilitate efficient viral cDNA synthesis soon after infection. Thus, we provide the evidence for a novel host protein that binds to HIV-1 IN and facilitates viral cDNA synthesis and subsequent steps that precede integration in vivo.
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Affiliation(s)
- Seiji Hamamoto
- Department of Immunotherapeutics, Tokyo Medical and Dental University, Tokyo 113-8519, Japan
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50
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Koyanagi Y. [Outline of HIV replication and its cellular factors: the track of an invader in the cell]. Uirusu 2006; 55:251-7. [PMID: 16557010 DOI: 10.2222/jsv.55.251] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
A number of novel findings with reference to HIV replication have been reported even though it passed more than 20 years after a first HIV isolation. Although many cellular factors are known to be involved in the HIV replication, recently investigators discovered novel HIV-suppressive cellular factors such as APOBEC or TRIM5 alpha. Here, I describe and discuss how HIV uses the cellular machinery for its replication.
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Affiliation(s)
- Yoshio Koyanagi
- Laboratory of Viral Pathogenesis, Institute for Virus Research, Kyoto University, Japan.
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