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Kikhai TF, Agapkina YY, Prikazchikova TA, Vdovina MV, Shekhtman SP, Fomicheva SV, Korolev SP, Gottikh MB. Role of I182, R187, and K188 Amino Acid Residues in the Catalytic Domain of HIV-1 Integrase in the Processes of Reverse Transcription and Integration. BIOCHEMISTRY. BIOKHIMIIA 2024; 89:462-473. [PMID: 38648766 DOI: 10.1134/s0006297924030076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2023] [Revised: 01/18/2024] [Accepted: 01/18/2024] [Indexed: 04/25/2024]
Abstract
Structural organization of HIV-1 integrase is based on a tetramer formed by two protein dimers. Within this tetramer, the catalytic domain of one subunit of the first dimer interacts with the N-terminal domain of the second dimer subunit. It is the tetrameric structure that allows both ends of the viral DNA to be correctly positioned relative to the cellular DNA and to realize catalytic functions of integrase, namely 3'-processing and strand transfer. However, during the HIV-1 replicative cycle, integrase is responsible not only for the integration stage, it is also involved in reverse transcription and is necessary at the stage of capsid formation of the newly formed virions. It has been suggested that HIV-1 integrase is a structurally dynamic protein and its biological functions depend on its structure. Accordingly, studying interactions between the domains of integrase that provide its tetrameric structure is important for understanding its multiple functions. In this work, we investigated the role of three amino acids of the catalytic domain, I182, R187, and K188, located in the contact region of two integrase dimers in the tetramer structure, in reverse transcription and integration. It has been shown that the R187 residue is extremely important for formation of the correct integrase structure, which is necessary at all stages of its functional activity. The I182 residue is necessary for successful integration and is not important for reverse transcription, while the K188 residue, on the contrary, is involved in formation of the integrase structure, which is important for the effective reverse transcription.
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Affiliation(s)
- Tatiana F Kikhai
- Faculty of Chemistry, Lomonosov Moscow State University, Moscow, 119991, Russia.
| | - Yulia Yu Agapkina
- Faculty of Chemistry, Lomonosov Moscow State University, Moscow, 119991, Russia
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119991, Russia
| | | | - Maria V Vdovina
- Faculty of Chemistry, Lomonosov Moscow State University, Moscow, 119991, Russia
| | - Sofia P Shekhtman
- Faculty of Chemistry, Lomonosov Moscow State University, Moscow, 119991, Russia
| | - Sofia V Fomicheva
- Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow, 119991, Russia
| | - Sergey P Korolev
- Faculty of Chemistry, Lomonosov Moscow State University, Moscow, 119991, Russia
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119991, Russia
| | - Marina B Gottikh
- Faculty of Chemistry, Lomonosov Moscow State University, Moscow, 119991, Russia.
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119991, Russia
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2
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Eilers G, Gupta K, Allen A, Montermoso S, Murali H, Sharp R, Hwang Y, Bushman FD, Van Duyne G. Structure of a HIV-1 IN-Allosteric inhibitor complex at 2.93 Å resolution: Routes to inhibitor optimization. PLoS Pathog 2023; 19:e1011097. [PMID: 36867659 PMCID: PMC10016701 DOI: 10.1371/journal.ppat.1011097] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Revised: 03/15/2023] [Accepted: 01/03/2023] [Indexed: 03/04/2023] Open
Abstract
HIV integrase (IN) inserts viral DNA into the host genome and is the target of the strand transfer inhibitors (STIs), a class of small molecules currently in clinical use. Another potent class of antivirals is the allosteric inhibitors of integrase, or ALLINIs. ALLINIs promote IN aggregation by stabilizing an interaction between the catalytic core domain (CCD) and carboxy-terminal domain (CTD) that undermines viral particle formation in late replication. Ongoing challenges with inhibitor potency, toxicity, and viral resistance motivate research to understand their mechanism. Here, we report a 2.93 Å X-ray crystal structure of the minimal ternary complex between CCD, CTD, and the ALLINI BI-224436. This structure reveals an asymmetric ternary complex with a prominent network of π-mediated interactions that suggest specific avenues for future ALLINI development and optimization.
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Affiliation(s)
- Grant Eilers
- Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Kushol Gupta
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Audrey Allen
- Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Saira Montermoso
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Hemma Murali
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Robert Sharp
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Young Hwang
- Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Frederic D. Bushman
- Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Gregory Van Duyne
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
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3
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Rocchi C, Louvat C, Miele AE, Batisse J, Guillon C, Ballut L, Lener D, Negroni M, Ruff M, Gouet P, Fiorini F. The HIV-1 Integrase C-Terminal Domain Induces TAR RNA Structural Changes Promoting Tat Binding. Int J Mol Sci 2022; 23:13742. [PMID: 36430221 PMCID: PMC9692563 DOI: 10.3390/ijms232213742] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Revised: 10/28/2022] [Accepted: 11/03/2022] [Indexed: 11/10/2022] Open
Abstract
Recent evidence indicates that the HIV-1 Integrase (IN) binds the viral genomic RNA (gRNA), playing a critical role in the morphogenesis of the viral particle and in the stability of the gRNA once in the host cell. By combining biophysical, molecular biology, and biochemical approaches, we found that the 18-residues flexible C-terminal tail of IN acts as a sensor of the peculiar apical structure of the trans-activation response element RNA (TAR), interacting with its hexaloop. We show that the binding of the whole IN C-terminal domain modifies TAR structure, exposing critical nucleotides. These modifications favour the subsequent binding of the HIV transcriptional trans-activator Tat to TAR, finally displacing IN from TAR. Based on these results, we propose that IN assists the binding of Tat to TAR RNA. This working model provides a mechanistic sketch accounting for the emerging role of IN in the early stages of proviral transcription and could help in the design of anti-HIV-1 therapeutics against this new target of the viral infectious cycle.
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Affiliation(s)
- Cecilia Rocchi
- Molecular Microbiology and Structural Biochemistry, MMSB-IBCP, UMR 5086, CNRS, University of Lyon, 7 Passage du Vercors, CEDEX 07, 69367 Lyon, France
| | - Camille Louvat
- Molecular Microbiology and Structural Biochemistry, MMSB-IBCP, UMR 5086, CNRS, University of Lyon, 7 Passage du Vercors, CEDEX 07, 69367 Lyon, France
| | - Adriana Erica Miele
- Institute of Analytical Sciences, UMR 5280 CNRS UCBL University of Lyon, 5 Rue de la Doua, 69100 Villeurbanne, France
- Department of Biochemical Sciences, Sapienza University of Rome, P.le Aldo Moro 5, 00185 Rome, Italy
| | - Julien Batisse
- Chromatin Stability and DNA Mobility, Department of Integrated Structural Biology, IGBMC, CNRS, UMR 7104—Inserm U 158, University of Strasbourg, 1 rue Laurent Fries, 67404 Illkirch, France
| | - Christophe Guillon
- Molecular Microbiology and Structural Biochemistry, MMSB-IBCP, UMR 5086, CNRS, University of Lyon, 7 Passage du Vercors, CEDEX 07, 69367 Lyon, France
| | - Lionel Ballut
- Molecular Microbiology and Structural Biochemistry, MMSB-IBCP, UMR 5086, CNRS, University of Lyon, 7 Passage du Vercors, CEDEX 07, 69367 Lyon, France
| | - Daniela Lener
- RNA Architecture and Reactivity, IBMC, CNRS, UPR 9002, University of Strasbourg, 2, Allée Konrad Roentgen, 67084 Strasbourg, France
| | - Matteo Negroni
- RNA Architecture and Reactivity, IBMC, CNRS, UPR 9002, University of Strasbourg, 2, Allée Konrad Roentgen, 67084 Strasbourg, France
| | - Marc Ruff
- Chromatin Stability and DNA Mobility, Department of Integrated Structural Biology, IGBMC, CNRS, UMR 7104—Inserm U 158, University of Strasbourg, 1 rue Laurent Fries, 67404 Illkirch, France
| | - Patrice Gouet
- Molecular Microbiology and Structural Biochemistry, MMSB-IBCP, UMR 5086, CNRS, University of Lyon, 7 Passage du Vercors, CEDEX 07, 69367 Lyon, France
| | - Francesca Fiorini
- Molecular Microbiology and Structural Biochemistry, MMSB-IBCP, UMR 5086, CNRS, University of Lyon, 7 Passage du Vercors, CEDEX 07, 69367 Lyon, France
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4
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Complex Relationships between HIV-1 Integrase and Its Cellular Partners. Int J Mol Sci 2022; 23:ijms232012341. [PMID: 36293197 PMCID: PMC9603942 DOI: 10.3390/ijms232012341] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Revised: 10/09/2022] [Accepted: 10/11/2022] [Indexed: 11/06/2022] Open
Abstract
RNA viruses, in pursuit of genome miniaturization, tend to employ cellular proteins to facilitate their replication. HIV-1, one of the most well-studied retroviruses, is not an exception. There is numerous evidence that the exploitation of cellular machinery relies on nucleic acid-protein and protein-protein interactions. Apart from Vpr, Vif, and Nef proteins that are known to regulate cellular functioning via interaction with cell components, another viral protein, integrase, appears to be crucial for proper virus-cell dialog at different stages of the viral life cycle. The goal of this review is to summarize and systematize existing data on known cellular partners of HIV-1 integrase and their role in the HIV-1 life cycle.
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5
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Rocchi C, Gouet P, Parissi V, Fiorini F. The C-Terminal Domain of HIV-1 Integrase: A Swiss Army Knife for the Virus? Viruses 2022; 14:v14071397. [PMID: 35891378 PMCID: PMC9316232 DOI: 10.3390/v14071397] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 06/22/2022] [Accepted: 06/22/2022] [Indexed: 12/31/2022] Open
Abstract
Retroviral integrase is a multimeric enzyme that catalyzes the integration of reverse-transcribed viral DNA into the cellular genome. Beyond integration, the Human immunodeficiency virus type 1 (HIV-1) integrase is also involved in many other steps of the viral life cycle, such as reverse transcription, nuclear import, virion morphogenesis and proviral transcription. All these additional functions seem to depend on the action of the integrase C-terminal domain (CTD) that works as a molecular hub, interacting with many different viral and cellular partners. In this review, we discuss structural issues concerning the CTD, with particular attention paid to its interaction with nucleic acids. We also provide a detailed map of post-translational modifications and interaction with molecular partners.
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Affiliation(s)
- Cecilia Rocchi
- Molecular Microbiology and Structural Biochemistry (MMSB), CNRS, University of Lyon 1, UMR 5086, 69367 Lyon, France; (C.R.); (P.G.)
- Viral DNA Integration and Chromatin Dynamics Network (DyNAVir), 33076 Bordeaux, France;
| | - Patrice Gouet
- Molecular Microbiology and Structural Biochemistry (MMSB), CNRS, University of Lyon 1, UMR 5086, 69367 Lyon, France; (C.R.); (P.G.)
- Viral DNA Integration and Chromatin Dynamics Network (DyNAVir), 33076 Bordeaux, France;
| | - Vincent Parissi
- Viral DNA Integration and Chromatin Dynamics Network (DyNAVir), 33076 Bordeaux, France;
- Fundamental Microbiology and Pathogenicity (MFP), CNRS, University of Bordeaux, UMR5234, 33405 Bordeaux, France
| | - Francesca Fiorini
- Molecular Microbiology and Structural Biochemistry (MMSB), CNRS, University of Lyon 1, UMR 5086, 69367 Lyon, France; (C.R.); (P.G.)
- Viral DNA Integration and Chromatin Dynamics Network (DyNAVir), 33076 Bordeaux, France;
- Correspondence: ; Tel.: +33-4-72722624; Fax: +33-4-72722616
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6
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Imamichi T, Bernbaum JG, Laverdure S, Yang J, Chen Q, Highbarger H, Hao M, Sui H, Dewar R, Chang W, Lane HC. Natural Occurring Polymorphisms in HIV-1 Integrase and RNase H Regulate Viral Release and Autoprocessing. J Virol 2021; 95:e0132321. [PMID: 34523971 PMCID: PMC8577372 DOI: 10.1128/jvi.01323-21] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Accepted: 09/07/2021] [Indexed: 01/19/2023] Open
Abstract
Recently, a genome-wide association study using plasma HIV RNA from antiretroviral therapy-naive patients reported that 14 naturally occurring nonsynonymous single-nucleotide polymorphisms (SNPs) in HIV derived from antiretrovirus drug-naive patients were associated with virus load (VL). Those SNPs were detected in reverse transcriptase, RNase H, integrase, envelope, and Nef. However, the impact of each mutation on viral fitness was not investigated. Here, we constructed a series of HIV variants encoding each SNP and examined their replicative abilities. An HIV variant containing a Met-to-Ile change at codon 50 in integrase [HIV(IN:M50I)] was found as an impaired virus. Despite the mutation being in integrase, the virus release was significantly suppressed (P < 0.001). Transmission electron microscopy analysis revealed that abnormal bud accumulation on the plasma membrane and the released virus particles retained immature forms. Western blot analysis demonstrated a defect in autoprocessing of GagPol and Gag polyproteins' autoprocessing in the HIV(IN:M50I) particles, although Förster resonance energy transfer (FRET) assay displayed that GagPol containing IN:M50I forms a homodimer with a similar efficiency with GagPol (wild type). The impaired maturation and replication were rescued by two other VL-associated SNPs, Ser-to-Asn change at codon 17 of integrase and Asn-to-Ser change at codon 79 of RNase H. These data demonstrate that Gag and GagPol assembly, virus release, and autoprocessing are regulated by not only integrase but also RNase H. IMPORTANCE Nascent HIV-1 is a noninfectious viral particle. Cleaving Gag and GagPol polyproteins in the particle by mature HIV protease (PR), the nascent virus becomes an infectious virus. PR is initially translated as an inactive embedded enzyme in a GagPol polyprotein. The embedded PR in homodimerized GagPol polyproteins catalyzes a proteolytic reaction to release the mature PR. This excision step by self-cleavage is called autoprocessing. Here, during the evaluation of the roles of naturally emerging nonsynonymous SNPs in HIV RNA, we found that autoprocessing is inhibited by Met-to-Ile change at codon 50 in integrase GagPol. Other coexisting SNPs, Ser-to-Asn change at codon 17 in integrase or Asn-to-Ser mutation at codon 79 in RNase H, recovered this defect, suggesting that autoprocessing is regulated by not only integrase but also RNase H in GagPol polyprotein.
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Affiliation(s)
- Tomozumi Imamichi
- Laboratory of Human Retrovirology and Immunoinformatics, Applied and Developmental Directorate, Frederick National Laboratory, Frederick, Maryland, USA
| | - John G. Bernbaum
- Integrated Research Facility, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Frederick, Maryland, USA
| | - Sylvain Laverdure
- Laboratory of Human Retrovirology and Immunoinformatics, Applied and Developmental Directorate, Frederick National Laboratory, Frederick, Maryland, USA
| | - Jun Yang
- Laboratory of Human Retrovirology and Immunoinformatics, Applied and Developmental Directorate, Frederick National Laboratory, Frederick, Maryland, USA
| | - Qian Chen
- Laboratory of Human Retrovirology and Immunoinformatics, Applied and Developmental Directorate, Frederick National Laboratory, Frederick, Maryland, USA
| | - Helene Highbarger
- Virus Isolation and Serology Laboratory, Applied and Developmental Directorate, Frederick National Laboratory, Frederick, Maryland, USA
| | - Ming Hao
- Laboratory of Human Retrovirology and Immunoinformatics, Applied and Developmental Directorate, Frederick National Laboratory, Frederick, Maryland, USA
| | - Hongyan Sui
- Laboratory of Human Retrovirology and Immunoinformatics, Applied and Developmental Directorate, Frederick National Laboratory, Frederick, Maryland, USA
| | - Robin Dewar
- Virus Isolation and Serology Laboratory, Applied and Developmental Directorate, Frederick National Laboratory, Frederick, Maryland, USA
| | - Weizhong Chang
- Laboratory of Human Retrovirology and Immunoinformatics, Applied and Developmental Directorate, Frederick National Laboratory, Frederick, Maryland, USA
| | - H. Clifford Lane
- Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
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7
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Abstract
To infect nondividing cells, HIV-1 needs to cross the nuclear membrane. The importin transportin-SR2 (TRN-SR2 or transportin-3) has been proposed to mediate HIV-1 nuclear import, but the detailed mechanism remains unresolved. The direct interaction of TRN-SR2 with HIV-1 integrase (IN) has been proposed to drive HIV-1 nuclear import. Alternatively, TRN-SR2 may play an indirect role by mediating nuclear import of cleavage and polyadenylation specificity factor 6 (CPSF6). To unravel the role of TRN-SR2, we designed CRISPR/Cas9 guide RNAs targeting different exons of TNPO3. Although this approach failed to generate full knockouts, monoallelic knockout clones were generated with indel mutations. HIV-1 replication was hampered in those clones at the level of HIV-1 nuclear import without an effect on the cellular distribution of the TRN-SR2 cargoes CPSF6 or alternative splicing factor1/pre-mRNA splicing factor SF2 (ASF/SF2). Recombinant ΔV105 TRN-SR2 expressed in clone 15.15 was 2-fold impaired for interaction with HIV-1 IN and classified as an interaction mutant. Our data support a model whereby TRN-SR2 acts as a cofactor of HIV-1 nuclear import without compromising the nuclear import of cellular cargoes. CRISPR/Cas9-induced mutagenesis can be used as a method to generate interface mutants to characterize host factors of human pathogens. IMPORTANCE Combination antiretroviral therapy (cART) effectively controls HIV-1 by reducing viral loads, but it does not cure the infection. Lifelong treatment with cART is a prerequisite for sustained viral suppression. The rapid emergence of drug-resistant viral strains drives the necessity to discover new therapeutic targets. The nuclear import of HIV-1 is crucial in the HIV-1 replication cycle, but the detailed mechanism remains incompletely understood. This study provides evidence that TRN-SR2 directly mediates HIV-1 nuclear import via the interaction with HIV-1 integrase. The interaction between those proteins is therefore a promising target toward a rational drug design which could lead to new therapeutic strategies due to the bottleneck nature of HIV-1 nuclear import.
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8
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Tabasi M, Nombela I, Janssens J, Lahousse AP, Christ F, Debyser Z. Role of Transportin-SR2 in HIV-1 Nuclear Import. Viruses 2021; 13:829. [PMID: 34064404 PMCID: PMC8147801 DOI: 10.3390/v13050829] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 04/29/2021] [Accepted: 05/02/2021] [Indexed: 12/14/2022] Open
Abstract
The HIV replication cycle depends on the interaction of viral proteins with proteins of the host. Unraveling host-pathogen interactions during the infection is of great importance for understanding the pathogenesis and the development of antiviral therapies. To date HIV uncoating and nuclear import are the most debated steps of the HIV-1 replication cycle. Despite numerous studies during past decades, there is still much controversy with respect to the identity and the role of viral and host factors involved in these processes. In this review, we provide a comprehensive overview on the role of transportin-SR2 as a host cell factor during active nuclear transport.
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Affiliation(s)
| | | | | | | | | | - Zeger Debyser
- Laboratory for Molecular Virology and Gene Therapy, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, 3000 Leuven, Flanders, Belgium; (M.T.); (I.N.); (J.J.); (A.P.L.); (F.C.)
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9
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Elliott JL, Eschbach JE, Koneru PC, Li W, Puray-Chavez M, Townsend D, Lawson DQ, Engelman AN, Kvaratskhelia M, Kutluay SB. Integrase-RNA interactions underscore the critical role of integrase in HIV-1 virion morphogenesis. eLife 2020; 9:54311. [PMID: 32960169 PMCID: PMC7671690 DOI: 10.7554/elife.54311] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Accepted: 09/22/2020] [Indexed: 01/29/2023] Open
Abstract
A large number of human immunodeficiency virus 1 (HIV-1) integrase (IN) alterations, referred to as class II substitutions, exhibit pleiotropic effects during virus replication. However, the underlying mechanism for the class II phenotype is not known. Here we demonstrate that all tested class II IN substitutions compromised IN-RNA binding in virions by one of the three distinct mechanisms: (i) markedly reducing IN levels thus precluding the formation of IN complexes with viral RNA; (ii) adversely affecting functional IN multimerization and consequently impairing IN binding to viral RNA; and (iii) directly compromising IN-RNA interactions without substantially affecting IN levels or functional IN multimerization. Inhibition of IN-RNA interactions resulted in the mislocalization of viral ribonucleoprotein complexes outside the capsid lattice, which led to premature degradation of the viral genome and IN in target cells. Collectively, our studies uncover causal mechanisms for the class II phenotype and highlight an essential role of IN-RNA interactions for accurate virion maturation.
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Affiliation(s)
- Jennifer L Elliott
- Department of Molecular Microbiology, Washington University School of Medicine, Saint Louis, United States
| | - Jenna E Eschbach
- Department of Molecular Microbiology, Washington University School of Medicine, Saint Louis, United States
| | - Pratibha C Koneru
- Division of Infectious Diseases, University of Colorado School of Medicine, Aurora, United States
| | - Wen Li
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, United States.,Department of Medicine, Harvard Medical School, Boston, United States
| | - Maritza Puray-Chavez
- Department of Molecular Microbiology, Washington University School of Medicine, Saint Louis, United States
| | - Dana Townsend
- Department of Molecular Microbiology, Washington University School of Medicine, Saint Louis, United States
| | - Dana Q Lawson
- Department of Molecular Microbiology, Washington University School of Medicine, Saint Louis, United States
| | - Alan N Engelman
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, United States.,Department of Medicine, Harvard Medical School, Boston, United States
| | - Mamuka Kvaratskhelia
- Division of Infectious Diseases, University of Colorado School of Medicine, Aurora, United States
| | - Sebla B Kutluay
- Department of Molecular Microbiology, Washington University School of Medicine, Saint Louis, United States
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10
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TNPO3-Mediated Nuclear Entry of the Rous Sarcoma Virus Gag Protein Is Independent of the Cargo-Binding Domain. J Virol 2020; 94:JVI.00640-20. [PMID: 32581109 DOI: 10.1128/jvi.00640-20] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2020] [Accepted: 06/16/2020] [Indexed: 11/20/2022] Open
Abstract
Retroviral Gag polyproteins orchestrate the assembly and release of nascent virus particles from the plasma membranes of infected cells. Although it was traditionally thought that Gag proteins trafficked directly from the cytosol to the plasma membrane, we discovered that the oncogenic avian alpharetrovirus Rous sarcoma virus (RSV) Gag protein undergoes transient nucleocytoplasmic transport as an intrinsic step in virus assembly. Using a genetic approach in yeast, we identified three karyopherins that engage the two independent nuclear localization signals (NLSs) in Gag. The primary NLS is in the nucleocapsid (NC) domain of Gag and binds directly to importin-α, which recruits importin-β to mediate nuclear entry. The second NLS (TNPO3), which resides in the matrix (MA) domain, is dependent on importin-11 and transportin-3 (TNPO3), which are known as MTR10p and Kap120p in yeast, although it is not clear whether these import factors are independent or additive. The functions of importin-α/importin-β and importin-11 have been verified in avian cells, whereas the role of TNPO3 has not been studied. In this report, we demonstrate that TNPO3 directly binds to Gag and mediates its nuclear entry. To our surprise, this interaction did not require the cargo-binding domain (CBD) of TNPO3, which typically mediates nuclear entry for other binding partners of TNPO3, including SR domain-containing splicing factors and tRNAs that reenter the nucleus. These results suggest that RSV hijacks this host nuclear import pathway using a unique mechanism, potentially allowing other cargo to simultaneously bind TNPO3.IMPORTANCE RSV Gag nuclear entry is facilitated using three distinct host import factors that interact with nuclear localization signals in the Gag MA and NC domains. Here, we show that the MA region is required for nuclear import of Gag through the TNPO3 pathway. Gag nuclear entry does not require the CBD of TNPO3. Understanding the molecular basis for TNPO3-mediated nuclear trafficking of the RSV Gag protein may lead to a deeper appreciation for whether different import factors play distinct roles in retrovirus replication.
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11
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Demeulemeester J, Blokken J, De Houwer S, Dirix L, Klaassen H, Marchand A, Chaltin P, Christ F, Debyser Z. Inhibitors of the integrase-transportin-SR2 interaction block HIV nuclear import. Retrovirology 2018; 15:5. [PMID: 29329553 PMCID: PMC5767004 DOI: 10.1186/s12977-018-0389-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2017] [Accepted: 11/20/2017] [Indexed: 12/12/2022] Open
Abstract
Background Combination antiretroviral therapy efficiently suppresses HIV replication in infected patients, transforming HIV/AIDS into a chronic disease. Viral resistance does develop however, especially under suboptimal treatment conditions such as poor adherence. As a consequence, continued exploration of novel targets is paramount to identify novel antivirals that do not suffer from cross-resistance with existing drugs. One new promising class of targets are HIV protein–cofactor interactions. Transportin-SR2 (TRN-SR2) is a β-karyopherin that was recently identified as an HIV-1 cofactor. It has been implicated in nuclear import of the viral pre-integration complex and was confirmed as a direct binding partner of HIV-1 integrase (IN). Nevertheless, consensus on its mechanism of action is yet to be reached. Results Here we describe the development and use of an AlphaScreen-based high-throughput screening cascade for small molecule inhibitors of the HIV-1 IN–TRN-SR2 interaction. False positives and nonspecific protein–protein interaction inhibitors were eliminated through different counterscreens. We identified and confirmed 2 active compound series from an initial screen of 25,608 small molecules. These compounds significantly reduced nuclear import of fluorescently labeled HIV particles. Conclusions Alphascreen-based high-throughput screening can allow the identification of compounds representing a novel class of HIV inhibitors. These results corroborate the role of the IN–TRN-SR2 interaction in nuclear import. These compounds represent the first in class small molecule inhibitors of HIV-1 nuclear import.
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Affiliation(s)
- Jonas Demeulemeester
- Laboratory for Molecular Virology and Gene Therapy, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, Kapucijnenvoer 33, VCTB +5, Bus 7001, 3000, Leuven, Flanders, Belgium.,The Francis Crick Institute, London, UK
| | - Jolien Blokken
- Laboratory for Molecular Virology and Gene Therapy, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, Kapucijnenvoer 33, VCTB +5, Bus 7001, 3000, Leuven, Flanders, Belgium
| | - Stéphanie De Houwer
- Laboratory for Molecular Virology and Gene Therapy, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, Kapucijnenvoer 33, VCTB +5, Bus 7001, 3000, Leuven, Flanders, Belgium
| | - Lieve Dirix
- Laboratory for Molecular Virology and Gene Therapy, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, Kapucijnenvoer 33, VCTB +5, Bus 7001, 3000, Leuven, Flanders, Belgium
| | - Hugo Klaassen
- Center for Innovation and Stimulation of Drug Discovery (CISTIM), Leuven, Belgium
| | - Arnaud Marchand
- Center for Innovation and Stimulation of Drug Discovery (CISTIM), Leuven, Belgium
| | - Patrick Chaltin
- Center for Innovation and Stimulation of Drug Discovery (CISTIM), Leuven, Belgium.,Center for Drug Design and Development (CD3), KU Leuven R&D, Leuven, Belgium
| | - Frauke Christ
- Laboratory for Molecular Virology and Gene Therapy, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, Kapucijnenvoer 33, VCTB +5, Bus 7001, 3000, Leuven, Flanders, Belgium
| | - Zeger Debyser
- Laboratory for Molecular Virology and Gene Therapy, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, Kapucijnenvoer 33, VCTB +5, Bus 7001, 3000, Leuven, Flanders, Belgium.
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12
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Tsirkone VG, Blokken J, De Wit F, Breemans J, De Houwer S, Debyser Z, Christ F, Strelkov SV. N-terminal half of transportin SR2 interacts with HIV integrase. J Biol Chem 2017; 292:9699-9710. [PMID: 28356354 PMCID: PMC5465493 DOI: 10.1074/jbc.m117.777029] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Revised: 03/14/2017] [Indexed: 11/06/2022] Open
Abstract
The karyopherin transportin SR2 (TRN-SR2, TNPO3) is responsible for shuttling specific cargoes such as serine/arginine-rich splicing factors from the cytoplasm to the nucleus. This protein plays a key role in HIV infection by facilitating the nuclear import of the pre-integration complex (PIC) that contains the viral DNA as well as several cellular and HIV proteins, including the integrase. The process of nuclear import is considered to be the bottleneck of the viral replication cycle and therefore represents a promising target for anti-HIV drug design. Previous studies have demonstrated that the direct interaction between TRN-SR2 and HIV integrase predominantly involves the catalytic core domain (CCD) and the C-terminal domain (CTD) of the integrase. We aimed at providing a detailed molecular view of this interaction through a biochemical characterization of the respective protein complex. Size-exclusion chromatography was used to characterize the interaction of TRN-SR2 with a truncated variant of the HIV-1 integrase, including both the CCD and CTD. These experiments indicate that one TRN-SR2 molecule can specifically bind one CCD-CTD dimer. Next, the regions of the solenoid-like TRN-SR2 molecule that are involved in the interaction with integrase were identified using AlphaScreen binding assays, revealing that the integrase interacts with the N-terminal half of TRN-SR2 principally through the HEAT repeats 4, 10, and 11. Combining these results with small-angle X-ray scattering data for the complex of TRN-SR2 with truncated integrase, we propose a molecular model of the complex. We speculate that nuclear import of the PIC may proceed concurrently with the normal nuclear transport.
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Affiliation(s)
| | - Jolien Blokken
- the Laboratory for Molecular Virology and Gene Therapy, KU Leuven, 3000 Leuven, Belgium
| | - Flore De Wit
- the Laboratory for Molecular Virology and Gene Therapy, KU Leuven, 3000 Leuven, Belgium
| | | | - Stéphanie De Houwer
- the Laboratory for Molecular Virology and Gene Therapy, KU Leuven, 3000 Leuven, Belgium
| | - Zeger Debyser
- the Laboratory for Molecular Virology and Gene Therapy, KU Leuven, 3000 Leuven, Belgium
| | - Frauke Christ
- the Laboratory for Molecular Virology and Gene Therapy, KU Leuven, 3000 Leuven, Belgium
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13
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Nakamura T, Campbell JR, Moore AR, Otsu S, Aikawa H, Tamamura H, Mitsuya H. Development and validation of a cell-based assay system to assess human immunodeficiency virus type 1 integrase multimerization. J Virol Methods 2016; 236:196-206. [PMID: 27474494 PMCID: PMC8188399 DOI: 10.1016/j.jviromet.2016.07.023] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Revised: 07/22/2016] [Accepted: 07/22/2016] [Indexed: 12/26/2022]
Abstract
Multimerization of HIV-1 integrase (IN) subunits is required for the concerted integration of HIV-1 proviral DNA into the host genome. Thus, the disruption of IN multimerization represents a new avenue for intervening HIV-1 infection. Here, we generated a cell-based assay system to assess IN multimerization using a newly constructed bimolecular fluorescence complementation (BiFC-IN) system. BiFC-IN proteins were efficient in emitting fluorescence, and amino acid (AA) substitutions associated with IN multimerization attenuated fluorescence, suggesting that the BiFC-IN system may be useful for evaluating the profile of IN multimerization. A recently reported non-catalytic site IN inhibitor (NCINI), which allosterically induces IN over-multimerization/aggregation, significantly increased fluorescence in the BiFC-IN system. An IN's substitution, A128T, associated with viral resistance to NCINIs, decreased the NCINI-induced increase of fluorescence, suggesting that A128T reduces the potential for IN over-multimerization. Moreover, E11K and F181T substitutions known to inhibit IN tetramerization also reduced the NCINI-induced fluorescence increase, suggesting that NCINI-induced IN over-multimerization was more likely to occur from tetramer subunits than from dimer subunits. The present study demonstrates that our cell-based BiFC-IN system may be useful in elucidating the profile of IN multimerization, and also help evaluate and identify novel compounds that disrupt IN multimerization in living cells.
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Affiliation(s)
- Tomofumi Nakamura
- Departments of Infectious Diseases and Hematology, Kumamoto University Graduate School of Medical Sciences, Kumamoto 860-8556, Japan
| | - Joseph R Campbell
- Departments of Infectious Diseases and Hematology, Kumamoto University Graduate School of Medical Sciences, Kumamoto 860-8556, Japan
| | - Amber R Moore
- Departments of Infectious Diseases and Hematology, Kumamoto University Graduate School of Medical Sciences, Kumamoto 860-8556, Japan
| | - Sachiko Otsu
- Departments of Infectious Diseases and Hematology, Kumamoto University Graduate School of Medical Sciences, Kumamoto 860-8556, Japan
| | - Haruo Aikawa
- Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University, Chiyoda-ku, Tokyo, 101-0062, Japan
| | - Hirokazu Tamamura
- Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University, Chiyoda-ku, Tokyo, 101-0062, Japan
| | - Hiroaki Mitsuya
- Departments of Infectious Diseases and Hematology, Kumamoto University Graduate School of Medical Sciences, Kumamoto 860-8556, Japan; Experimental Retrovirology Section, National Center for Global Health and Medicine Research Institute, Shinjuku, Tokyo 162-8655, Japan; HIV and AIDS Malignancy Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA.
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14
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Abstract
The HIV genome encodes a small number of viral proteins (i.e., 16), invariably establishing cooperative associations among HIV proteins and between HIV and host proteins, to invade host cells and hijack their internal machineries. As a known example, the HIV envelope glycoprotein GP120 is closely associated with GP41 for viral entry. From a genome-wide perspective, a hypothesis can be worked out to determine whether 16 HIV proteins could develop 120 possible pairwise associations either by physical interactions or by functional associations mediated via HIV or host molecules. Here, we present the first systematic review of experimental evidence on HIV genome-wide protein associations using a large body of publications accumulated over the past 3 decades. Of 120 possible pairwise associations between 16 HIV proteins, at least 34 physical interactions and 17 functional associations have been identified. To achieve efficient viral replication and infection, HIV protein associations play essential roles (e.g., cleavage, inhibition, and activation) during the HIV life cycle. In either a dispensable or an indispensable manner, each HIV protein collaborates with another viral protein to accomplish specific activities that precisely take place at the proper stages of the HIV life cycle. In addition, HIV genome-wide protein associations have an impact on anti-HIV inhibitors due to the extensive cross talk between drug-inhibited proteins and other HIV proteins. Overall, this study presents for the first time a comprehensive overview of HIV genome-wide protein associations, highlighting meticulous collaborations between all viral proteins during the HIV life cycle.
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Affiliation(s)
- Guangdi Li
- Department of Metabolism and Endocrinology, Metabolic Syndrome Research Center, Key Laboratory of Diabetes Immunology, Ministry of Education, National Clinical Research Center for Metabolic Diseases, The Second Xiangya Hospital, Central South University, Changsha, Hunan, China KU Leuven-University of Leuven, Rega Institute for Medical Research, Department of Microbiology and Immunology, Leuven, Belgium
| | - Erik De Clercq
- KU Leuven-University of Leuven, Rega Institute for Medical Research, Department of Microbiology and Immunology, Leuven, Belgium
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15
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HIV Genome-Wide Protein Associations: a Review of 30 Years of Research. Microbiol Mol Biol Rev 2016; 80:679-731. [PMID: 27357278 DOI: 10.1128/mmbr.00065-15] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The HIV genome encodes a small number of viral proteins (i.e., 16), invariably establishing cooperative associations among HIV proteins and between HIV and host proteins, to invade host cells and hijack their internal machineries. As a known example, the HIV envelope glycoprotein GP120 is closely associated with GP41 for viral entry. From a genome-wide perspective, a hypothesis can be worked out to determine whether 16 HIV proteins could develop 120 possible pairwise associations either by physical interactions or by functional associations mediated via HIV or host molecules. Here, we present the first systematic review of experimental evidence on HIV genome-wide protein associations using a large body of publications accumulated over the past 3 decades. Of 120 possible pairwise associations between 16 HIV proteins, at least 34 physical interactions and 17 functional associations have been identified. To achieve efficient viral replication and infection, HIV protein associations play essential roles (e.g., cleavage, inhibition, and activation) during the HIV life cycle. In either a dispensable or an indispensable manner, each HIV protein collaborates with another viral protein to accomplish specific activities that precisely take place at the proper stages of the HIV life cycle. In addition, HIV genome-wide protein associations have an impact on anti-HIV inhibitors due to the extensive cross talk between drug-inhibited proteins and other HIV proteins. Overall, this study presents for the first time a comprehensive overview of HIV genome-wide protein associations, highlighting meticulous collaborations between all viral proteins during the HIV life cycle.
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16
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Abstract
In a mature, infectious HIV-1 virion, the viral genome is housed within a conical capsid core made from the viral capsid (CA) protein. The CA protein and the structure into which it assembles facilitate virtually every step of infection through a series of interactions with multiple host cell factors. This Review describes our understanding of the interactions between the viral capsid core and several cellular factors that enable efficient HIV-1 genome replication, timely core disassembly, nuclear import and the integration of the viral genome into the genome of the target cell. We then discuss how elucidating these interactions can reveal new targets for therapeutic interactions against HIV-1.
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17
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Ali MK, Kim J, Hamid FB, Shin CG. Knockdown of the host cellular protein transportin 3 attenuates prototype foamy virus infection. Biosci Biotechnol Biochem 2015; 79:943-51. [PMID: 25660973 DOI: 10.1080/09168451.2015.1008973] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Transportin 3 (TNPO3) is a member of the importin-ß superfamily proteins. Despite numerous studies, the exact molecular mechanism of TNPO3 in retroviral infection is still controversial. Here, we provide evidence for the role and mechanism of TNPO3 in the replication of prototype foamy virus (PFV). Our findings revealed that PFV infection was reduced 2-fold by knockdown (KD) of TNPO3. However, late stage of viral replication including transcription, translation, viral assembly, and release was not influenced. The differential cellular localization of PFV integrase (IN) in KD cells pinpointed a remarkable reduction of viral replication at the nuclear import step. We also found that TNPO3 interacted with PFV IN but not with Gag, suggesting that IN-TNPO3 interaction is important for nuclear import of PFV pre-integration complex. Our report enlightens the mechanism of PFV interaction with TNPO3 and support ongoing research on PFV as a promising safe vector for gene therapy.
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Affiliation(s)
- Md Khadem Ali
- a Department of Systems Biotechnology , Chung Ang University , Ansung , Republic of Korea
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18
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Comparison Between Several Integrase-defective Lentiviral Vectors Reveals Increased Integration of an HIV Vector Bearing a D167H Mutant. MOLECULAR THERAPY-NUCLEIC ACIDS 2014; 3:e213. [PMID: 25462529 PMCID: PMC4272407 DOI: 10.1038/mtna.2014.65] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/13/2014] [Accepted: 10/09/2014] [Indexed: 01/20/2023]
Abstract
HIV-1 derived vectors are among the most efficient for gene transduction in mammalian tissues. As the parent virus, they carry out vector genome insertion into the host cell chromatin. Consequently, their preferential integration in transcribed genes raises several conceptual and safety issues. To address part of these questions, HIV-derived vectors have been engineered to be nonintegrating. This was mainly achieved by mutating HIV-1 integrase at functional hotspots of the enzyme enabling the development of streamlined nuclear DNA circles functional for transgene expression. Few integrase mutant vectors have been successfully tested so far for gene transfer. They are cleared with time in mitotic cells, but stable within nondividing retina cells or neurons. Here, we compared six HIV vectors carrying different integrases, either wild type or with different mutations (D64V, D167H, Q168A, K186Q+Q214L+Q216L, and RRK262-264AAH) shown to modify integrase enzymatic activity, oligomerization, or interaction with key cellular cofactor of HIV DNA integration as LEDGF/p75 or TNPO3. We show that these mutations differently affect the transduction efficiency as well as rates and patterns of integration of HIV-derived vectors suggesting their different processing in the nucleus. Surprisingly and most interestingly, we report that an integrase carrying the D167H substitution improves vector transduction efficiency and integration in both HEK-293T and primary CD34+ cells.
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19
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Abstract
UNLABELLED Genetic robustness (tolerance of mutation) may be a naturally selected property in some viruses, because it should enhance adaptability. Robustness should be especially beneficial to viruses like HIV-1 that exhibit high mutation rates and exist in immunologically hostile environments. Surprisingly, however, the HIV-1 capsid protein (CA) exhibits extreme fragility. To determine whether fragility is a general property of HIV-1 proteins, we created a large library of random, single-amino-acid mutants in HIV-1 integrase (IN), covering >40% of amino acid positions. Despite similar degrees of sequence variation in naturally occurring IN and CA sequences, we found that HIV-1 IN was significantly more robust than CA, with random nonsilent IN mutations only half as likely to cause lethal defects. Interestingly, IN and CA were similar in that a subset of mutations with high in vitro fitness were rare in natural populations. IN mutations of this type were more likely to occur in the buried interior of the modeled HIV-1 intasome, suggesting that even very subtle fitness effects suppress variation in natural HIV-1 populations. Lethal mutations, in particular those that perturbed particle production, proteolytic processing, and particle-associated IN levels, were strikingly localized at specific IN subunit interfaces. This observation strongly suggests that binding interactions between particular IN subunits regulate proteolysis during HIV-1 virion morphogenesis. Overall, use of the IN mutant library in conjunction with structural models demonstrates the overall robustness of IN and highlights particular regions of vulnerability that may be targeted in therapeutic interventions. IMPORTANCE The HIV-1 integrase (IN) protein is responsible for the integration of the viral genome into the host cell chromosome. To measure the capacity of IN to maintain function in the face of mutation, and to probe structure/function relationships, we created a library of random single-amino-acid IN mutations that could mimic the types of mutations that naturally occur during HIV-1 infection. Previously, we measured the robustness of HIV-1 capsid in this manner and determined that it is extremely intolerant of mutation. In contrast to CA, HIV-1 IN proved relatively robust, with far fewer mutations causing lethal defects. However, when we subsequently mapped the lethal mutations onto a model of the structure of the multisubunit IN-viral DNA complex, we found the lethal mutations that caused virus morphogenesis defects tended to be highly localized at subunit interfaces. This discovery of vulnerable regions of HIV-1 IN could inform development of novel therapeutics.
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De Houwer S, Demeulemeester J, Thys W, Rocha S, Dirix L, Gijsbers R, Christ F, Debyser Z. The HIV-1 integrase mutant R263A/K264A is 2-fold defective for TRN-SR2 binding and viral nuclear import. J Biol Chem 2014; 289:25351-61. [PMID: 25063804 DOI: 10.1074/jbc.m113.533281] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Transportin-SR2 (Tnpo3, TRN-SR2), a human karyopherin encoded by the TNPO3 gene, has been identified as a cellular cofactor of HIV-1 replication, specifically interacting with HIV-1 integrase (IN). Whether this interaction mediates the nuclear import of HIV remains controversial. We previously characterized the TRN-SR2 binding interface in IN and introduced mutations at these positions to corroborate the biological relevance of the interaction. The pleiotropic nature of IN mutations complicated the interpretation. Indeed, all previously tested IN interaction mutants also affected RT. Here we report on a virus with a pair of IN mutations, IN(R263A/K264A), that significantly reduce interaction with TRN-SR2. The virus retains wild-type reverse transcription activity but displays a block in nuclear import and integration, as measured by quantitative PCR. The defect in integration of this mutant resulted in a smaller increase in the number of two-long terminal repeat circles than for virus specifically blocked at integration by raltegravir or catalytic site mutations (IN(D64N/D116N/E152Q)). Finally, using an eGFP-IN-labeled HIV fluorescence-based import assay, the defect in nuclear import was corroborated. These data altogether underscore the importance of the HIV-IN TRN-SR2 protein-protein interaction for HIV nuclear import and validate the IN/TRN-SR2 interaction interface as a promising target for future antiviral therapy.
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Affiliation(s)
- Stéphanie De Houwer
- From the Laboratory for Molecular Virology and Gene Therapy, Department of Pharmaceutical and Pharmacological Sciences, Katholieke Universiteit Leuven, 3000, Leuven, Belgium
| | - Jonas Demeulemeester
- From the Laboratory for Molecular Virology and Gene Therapy, Department of Pharmaceutical and Pharmacological Sciences, Katholieke Universiteit Leuven, 3000, Leuven, Belgium
| | - Wannes Thys
- From the Laboratory for Molecular Virology and Gene Therapy, Department of Pharmaceutical and Pharmacological Sciences, Katholieke Universiteit Leuven, 3000, Leuven, Belgium
| | - Susana Rocha
- From the Laboratory for Molecular Virology and Gene Therapy, Department of Pharmaceutical and Pharmacological Sciences, Katholieke Universiteit Leuven, 3000, Leuven, Belgium
| | - Lieve Dirix
- From the Laboratory for Molecular Virology and Gene Therapy, Department of Pharmaceutical and Pharmacological Sciences, Katholieke Universiteit Leuven, 3000, Leuven, Belgium
| | - Rik Gijsbers
- From the Laboratory for Molecular Virology and Gene Therapy, Department of Pharmaceutical and Pharmacological Sciences, Katholieke Universiteit Leuven, 3000, Leuven, Belgium
| | - Frauke Christ
- From the Laboratory for Molecular Virology and Gene Therapy, Department of Pharmaceutical and Pharmacological Sciences, Katholieke Universiteit Leuven, 3000, Leuven, Belgium
| | - Zeger Debyser
- From the Laboratory for Molecular Virology and Gene Therapy, Department of Pharmaceutical and Pharmacological Sciences, Katholieke Universiteit Leuven, 3000, Leuven, Belgium
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21
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Tsirkone VG, Beutels KG, Demeulemeester J, Debyser Z, Christ F, Strelkov SV. Structure of transportin SR2, a karyopherin involved in human disease, in complex with Ran. Acta Crystallogr F Struct Biol Commun 2014; 70:723-9. [PMID: 24915079 PMCID: PMC4051523 DOI: 10.1107/s2053230x14009492] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2014] [Accepted: 04/28/2014] [Indexed: 11/10/2022] Open
Abstract
Transportin SR2 (TRN-SR2) is a β-type karyopherin responsible for the nuclear import of specific cargoes, including serine/arginine-rich splicing factors. The protein has been implicated in a variety of human diseases, including HIV infection, primary biliary cirrhosis and limb-girdle muscular dystrophy 1F. Towards understanding its molecular mechanism, a 2.9 Å resolution crystal structure of human TRN-SR2 complexed with the small GTPase Ran has been determined. TRN-SR2 is composed of 20 α-helical HEAT repeats forming a solenoid-like fold. The first nine repeats form a `cradle' for the binding of RanGTP, revealing similarities but also differences with respect to the related importin 13 complex.
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Affiliation(s)
- Vicky G. Tsirkone
- Laboratory for Biocrystallography, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, Herestraat 49 bus 822, 3000 Leuven, Belgium
| | - Katrien G. Beutels
- Laboratory for Biocrystallography, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, Herestraat 49 bus 822, 3000 Leuven, Belgium
| | - Jonas Demeulemeester
- Laboratory of Molecular Virology and Gene Therapy, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, Herestraat 49 bus 822, 3000 Leuven, Belgium
| | - Zeger Debyser
- Laboratory of Molecular Virology and Gene Therapy, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, Herestraat 49 bus 822, 3000 Leuven, Belgium
| | - Frauke Christ
- Laboratory of Molecular Virology and Gene Therapy, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, Herestraat 49 bus 822, 3000 Leuven, Belgium
| | - Sergei V. Strelkov
- Laboratory for Biocrystallography, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, Herestraat 49 bus 822, 3000 Leuven, Belgium
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22
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Viral and cellular requirements for the nuclear entry of retroviral preintegration nucleoprotein complexes. Viruses 2013; 5:2483-511. [PMID: 24103892 PMCID: PMC3814599 DOI: 10.3390/v5102483] [Citation(s) in RCA: 91] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2013] [Revised: 09/26/2013] [Accepted: 10/03/2013] [Indexed: 02/07/2023] Open
Abstract
Retroviruses integrate their reverse transcribed genomes into host cell chromosomes as an obligate step in virus replication. The nuclear envelope separates the chromosomes from the cell cytoplasm during interphase, and different retroviral groups deal with this physical barrier in different ways. Gammaretroviruses are dependent on the passage of target cells through mitosis, where they are believed to access chromosomes when the nuclear envelope dissolves for cell division. Contrastingly, lentiviruses such as HIV-1 infect non-dividing cells, and are believed to enter the nucleus by passing through the nuclear pore complex. While numerous virally encoded elements have been proposed to be involved in HIV-1 nuclear import, recent evidence has highlighted the importance of HIV-1 capsid. Furthermore, capsid was found to be responsible for the viral requirement of various nuclear transport proteins, including transportin 3 and nucleoporins NUP153 and NUP358, during infection. In this review, we describe our current understanding of retroviral nuclear import, with emphasis on recent developments on the role of the HIV-1 capsid protein.
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23
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Taltynov O, Demeulemeester J, Christ F, De Houwer S, Tsirkone VG, Gerard M, Weeks SD, Strelkov SV, Debyser Z. Interaction of transportin-SR2 with Ras-related nuclear protein (Ran) GTPase. J Biol Chem 2013; 288:25603-25613. [PMID: 23878195 DOI: 10.1074/jbc.m113.484345] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
The human immunodeficiency virus type 1 (HIV-1) and other lentiviruses are capable of infecting non-dividing cells and, therefore, need to be imported into the nucleus before integration into the host cell chromatin. Transportin-SR2 (TRN-SR2, Transportin-3, TNPO3) is a cellular karyopherin implicated in nuclear import of HIV-1. A model in which TRN-SR2 imports the viral preintegration complex into the nucleus is supported by direct interaction between TRN-SR2 and HIV-1 integrase (IN). Residues in the C-terminal domain of HIV-1 IN that mediate binding to TRN-SR2 were recently delineated. As for most nuclear import cargoes, the driving force behind HIV-1 preintegration complex import is likely a gradient of the GDP- and GTP-bound forms of Ran, a small GTPase. In this study we offer biochemical and structural characterization of the interaction between TRN-SR2 and Ran. By size exclusion chromatography we demonstrate stable complex formation of TRN-SR2 and RanGTP in solution. Consistent with the behavior of normal nuclear import cargoes, HIV-1 IN is released from the complex with TRN-SR2 by RanGTP. Although in concentrated solutions TRN-SR2 by itself was predominantly present as a dimer, the TRN-SR2-RanGTP complex was significantly more compact. Further analysis supported a model wherein one monomer of TRN-SR2 is bound to one monomer of RanGTP. Finally, we present a homology model of the TRN-SR2-RanGTP complex that is in excellent agreement with the experimental small angle x-ray scattering data.
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Affiliation(s)
- Oliver Taltynov
- From the Laboratory for Molecular Virology and Gene Therapy and
| | | | - Frauke Christ
- From the Laboratory for Molecular Virology and Gene Therapy and
| | | | - Vicky G Tsirkone
- Laboratory for Biocrystallography, KU Leuven, B-3000 Leuven, Belgium
| | - Melanie Gerard
- From the Laboratory for Molecular Virology and Gene Therapy and
| | - Stephen D Weeks
- Laboratory for Biocrystallography, KU Leuven, B-3000 Leuven, Belgium
| | - Sergei V Strelkov
- Laboratory for Biocrystallography, KU Leuven, B-3000 Leuven, Belgium
| | - Zeger Debyser
- From the Laboratory for Molecular Virology and Gene Therapy and.
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24
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Khadem Ali M, Alamgir Hossain M, Shin CG. Comparative sequence and expression analyses of African green monkey (Cercopithecus aethiops) TNPO3 from CV-1 cells. Genes Genomics 2013. [DOI: 10.1007/s13258-013-0102-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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