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Grandgenett DP, Engelman AN. Brief Histories of Retroviral Integration Research and Associated International Conferences. Viruses 2024; 16:604. [PMID: 38675945 PMCID: PMC11054761 DOI: 10.3390/v16040604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2024] [Revised: 04/05/2024] [Accepted: 04/10/2024] [Indexed: 04/28/2024] Open
Abstract
The field of retroviral integration research has a long history that started with the provirus hypothesis and subsequent discoveries of the retroviral reverse transcriptase and integrase enzymes. Because both enzymes are essential for retroviral replication, they became valued targets in the effort to discover effective compounds to inhibit HIV-1 replication. In 2007, the first integrase strand transfer inhibitor was licensed for clinical use, and subsequently approved second-generation integrase inhibitors are now commonly co-formulated with reverse transcriptase inhibitors to treat people living with HIV. International meetings specifically focused on integrase and retroviral integration research first convened in 1995, and this paper is part of the Viruses Special Issue on the 7th International Conference on Retroviral Integration, which was held in Boulder Colorado in the summer of 2023. Herein, we overview key historical developments in the field, especially as they pertain to the development of the strand transfer inhibitor drug class. Starting from the mid-1990s, research advancements are presented through the lens of the international conferences. Our overview highlights the impact that regularly scheduled, subject-specific international meetings can have on community-building and, as a result, on field-specific collaborations and scientific advancements.
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Affiliation(s)
- Duane P. Grandgenett
- Department of Molecular Microbiology and Immunology, School of Medicine, Saint Louis University, St. Louis, MO 63104, USA
| | - 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
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2
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Renzi G, Carta F, Supuran CT. The Integrase: An Overview of a Key Player Enzyme in the Antiviral Scenario. Int J Mol Sci 2023; 24:12187. [PMID: 37569561 PMCID: PMC10419282 DOI: 10.3390/ijms241512187] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Revised: 07/23/2023] [Accepted: 07/26/2023] [Indexed: 08/13/2023] Open
Abstract
Integration of a desossiribonucleic acid (DNA) copy of the viral ribonucleic acid (RNA) into host genomes is a fundamental step in the replication cycle of all retroviruses. The highly conserved virus-encoded Integrase enzyme (IN; EC 2.7.7.49) catalyzes such a process by means of two consecutive reactions named 3'-processing (3-P) and strand transfer (ST). The Authors report and discuss the major discoveries and advances which mainly contributed to the development of Human Immunodeficiency Virus (HIV) -IN targeted inhibitors for therapeutic applications. All the knowledge accumulated over the years continues to serve as a valuable resource for the design and development of effective antiretroviral drugs.
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Affiliation(s)
| | - Fabrizio Carta
- Neuroscienze, Psicologia, Area del Farmaco e Salute del Bambino (NEUROFARBA) Department, Sezione di Scienze Farmaceutiche e Nutraceutiche, University of Florence, Via Ugo Schiff 6, Sesto Fiorentino, 50019 Florence, Italy; (G.R.); (C.T.S.)
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3
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Li M, Oliveira Passos D, Shan Z, Smith SJ, Sun Q, Biswas A, Choudhuri I, Strutzenberg TS, Haldane A, Deng N, Li Z, Zhao XZ, Briganti L, Kvaratskhelia M, Burke TR, Levy RM, Hughes SH, Craigie R, Lyumkis D. Mechanisms of HIV-1 integrase resistance to dolutegravir and potent inhibition of drug-resistant variants. SCIENCE ADVANCES 2023; 9:eadg5953. [PMID: 37478179 DOI: 10.1126/sciadv.adg5953] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Accepted: 06/16/2023] [Indexed: 07/23/2023]
Abstract
HIV-1 infection depends on the integration of viral DNA into host chromatin. Integration is mediated by the viral enzyme integrase and is blocked by integrase strand transfer inhibitors (INSTIs), first-line antiretroviral therapeutics widely used in the clinic. Resistance to even the best INSTIs is a problem, and the mechanisms of resistance are poorly understood. Here, we analyze combinations of the mutations E138K, G140A/S, and Q148H/K/R, which confer resistance to INSTIs. The investigational drug 4d more effectively inhibited the mutants compared with the approved drug Dolutegravir (DTG). We present 11 new cryo-EM structures of drug-resistant HIV-1 intasomes bound to DTG or 4d, with better than 3-Å resolution. These structures, complemented with free energy simulations, virology, and enzymology, explain the mechanisms of DTG resistance involving E138K + G140A/S + Q148H/K/R and show why 4d maintains potency better than DTG. These data establish a foundation for further development of INSTIs that potently inhibit resistant forms in integrase.
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Affiliation(s)
- Min Li
- National Institute of Diabetes and Digestive Diseases, National Institutes of Health, Bethesda, MD, 20892, USA
| | | | - Zelin Shan
- The Salk Institute for Biological Studies, La Jolla, CA, 92037, USA
| | - Steven J Smith
- Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, MD, 21702, USA
| | - Qinfang Sun
- Center for Biophysics and Computational Biology, and Department of Chemistry, Temple University, Philadelphia, PA 19122, USA
| | - Avik Biswas
- The Salk Institute for Biological Studies, La Jolla, CA, 92037, USA
- Center for Biophysics and Computational Biology and Department of Physics, Temple University, Philadelphia, PA 19122, USA
| | - Indrani Choudhuri
- Center for Biophysics and Computational Biology, and Department of Chemistry, Temple University, Philadelphia, PA 19122, USA
| | | | - Allan Haldane
- Center for Biophysics and Computational Biology and Department of Physics, Temple University, Philadelphia, PA 19122, USA
| | - Nanjie Deng
- Department of Chemistry and Physical Sciences, Pace University, New York, NY, 10038, USA
| | - Zhaoyang Li
- National Institute of Diabetes and Digestive Diseases, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Xue Zhi Zhao
- Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, MD, 21702, USA
| | - Lorenzo Briganti
- Division of Infectious Diseases, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Mamuka Kvaratskhelia
- Division of Infectious Diseases, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Terrence R Burke
- Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, MD, 21702, USA
| | - Ronald M Levy
- Center for Biophysics and Computational Biology and Department of Physics, Temple University, Philadelphia, PA 19122, USA
| | - Stephen H Hughes
- Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, MD, 21702, USA
| | - Robert Craigie
- National Institute of Diabetes and Digestive Diseases, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Dmitry Lyumkis
- The Salk Institute for Biological Studies, La Jolla, CA, 92037, USA
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA, 92037, USA
- Graduate School of Biological Sciences, Section of Molecular Biology, University of California San Diego, La Jolla, CA 92093, USA
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HIV-1 Preintegration Complex Preferentially Integrates the Viral DNA into Nucleosomes Containing Trimethylated Histone 3-Lysine 36 Modification and Flanking Linker DNA. J Virol 2022; 96:e0101122. [PMID: 36094316 PMCID: PMC9517705 DOI: 10.1128/jvi.01011-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
HIV-1 DNA is preferentially integrated into chromosomal hot spots by the preintegration complex (PIC). To understand the mechanism, we measured the DNA integration activity of PICs-extracted from infected cells-and intasomes, biochemically assembled PIC substructures using a number of relevant target substrates. We observed that PIC-mediated integration into human chromatin is preferred compared to genomic DNA. Surprisingly, nucleosomes lacking histone modifications were not preferred integration compared to the analogous naked DNA. Nucleosomes containing the trimethylated histone 3 lysine 36 (H3K36me3), an epigenetic mark linked to active transcription, significantly stimulated integration, but the levels remained lower than the naked DNA. Notably, H3K36me3-modified nucleosomes with linker DNA optimally supported integration mediated by the PIC but not by the intasome. Interestingly, optimal intasome-mediated integration required the cellular cofactor LEDGF. Unexpectedly, LEDGF minimally affected PIC-mediated integration into naked DNA but blocked integration into nucleosomes. The block for the PIC-mediated integration was significantly relieved by H3K36me3 modification. Mapping the integration sites in the preferred substrates revealed that specific features of the nucleosome-bound DNA are preferred for integration, whereas integration into naked DNA was random. Finally, biochemical and genetic studies demonstrate that DNA condensation by the H1 protein dramatically reduces integration, providing further evidence that features inherent to the open chromatin are preferred for HIV-1 integration. Collectively, these results identify the optimal target substrate for HIV-1 integration, report a mechanistic link between H3K36me3 and integration preference, and importantly, reveal distinct mechanisms utilized by the PIC for integration compared to the intasomes. IMPORTANCE HIV-1 infection is dependent on integration of the viral DNA into the host chromosomes. The preintegration complex (PIC) containing the viral DNA, the virally encoded integrase (IN) enzyme, and other viral/host factors carries out HIV-1 integration. HIV-1 integration is not dependent on the target DNA sequence, and yet the viral DNA is selectively inserted into specific "hot spots" of human chromosomes. A growing body of literature indicates that structural features of the human chromatin are important for integration targeting. However, the mechanisms that guide the PIC and enable insertion of the PIC-associated viral DNA into specific hot spots of the human chromosomes are not fully understood. In this study, we describe a biochemical mechanism for the preference of the HIV-1 DNA integration into open chromatin. Furthermore, our study defines a direct role for the histone epigenetic mark H3K36me3 in HIV-1 integration preference and identify an optimal substrate for HIV-1 PIC-mediated viral DNA integration.
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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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Davids BO, Balasubramaniam M, Sapp N, Prakash P, Ingram S, Li M, Craigie R, Hollis T, Pandhare J, Dash C. Human Three Prime Repair Exonuclease 1 Promotes HIV-1 Integration by Preferentially Degrading Unprocessed Viral DNA. J Virol 2021; 95:e0055521. [PMID: 34105995 PMCID: PMC8354242 DOI: 10.1128/jvi.00555-21] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Accepted: 05/25/2021] [Indexed: 11/20/2022] Open
Abstract
Three prime repair exonuclease 1 (TREX1) is the most abundant 3'→5' exonuclease in mammalian cells. It has been suggested that TREX1 degrades HIV-1 DNA to enable the virus to evade the innate immune system. However, the exact role of TREX1 during early steps of HIV-1 infection is not clearly understood. In this study, we report that HIV-1 infection is associated with upregulation, perinuclear accumulation, and nuclear localization of TREX1. However, TREX1 overexpression did not affect reverse transcription or nuclear entry of the virus. Surprisingly, HIV-1 DNA integration was increased in TREX1-overexpressing cells, suggesting a role of the exonuclease in the post-nuclear entry step of infection. Accordingly, preintegration complexes (PICs) extracted from TREX1-overexpressing cells retained higher levels of DNA integration activity. TREX1 depletion resulted in reduced levels of proviral integration, and PICs formed in TREX1-depleted cells retained lower DNA integration activity. Addition of purified TREX1 to PICs also enhanced DNA integration activity, suggesting that TREX1 promotes HIV-1 integration by stimulating PIC activity. To understand the mechanism, we measured TREX1 exonuclease activity on substrates containing viral DNA ends. These studies revealed that TREX1 preferentially degrades the unprocessed viral DNA, but the integration-competent 3'-processed viral DNA remains resistant to degradation. Finally, we observed that TREX1 addition stimulates the activity of HIV-1 intasomes assembled with the unprocessed viral DNA but not that of intasomes containing the 3'-processed viral DNA. These biochemical analyses provide a mechanism by which TREX1 directly promotes HIV-1 integration. Collectively, our study demonstrates that HIV-1 infection upregulates TREX1 to facilitate viral DNA integration. IMPORTANCE Productive HIV-1 infection is dependent on a number of cellular factors. Therefore, a clear understanding of how the virus exploits the cellular machinery will identify new targets for inhibiting HIV-1 infection. The three prime repair exonuclease 1 (TREX1) is the most active cellular exonuclease in mammalian cells. It has been reported that TREX1 prevents accumulation of HIV-1 DNA and enables the virus to evade the host innate immune response. Here, we show that HIV-1 infection results in the upregulation, perinuclear accumulation, and nuclear localization of TREX1. We also provide evidence that TREX1 promotes HIV-1 integration by preferentially degrading viral DNAs that are incompatible with chromosomal insertion. These observations identify a novel role of TREX1 in a post-nuclear entry step of HIV-1 infection.
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Affiliation(s)
- Benem-Orom Davids
- Center for AIDS Health Disparities Research, Meharry Medical College, Nashville, Tennessee, USA
- Department of Biochemistry, Cancer Biology, Pharmacology and Neuroscience, Meharry Medical College, Nashville, Tennessee, USA
| | - Muthukumar Balasubramaniam
- Center for AIDS Health Disparities Research, Meharry Medical College, Nashville, Tennessee, USA
- Department of Biochemistry, Cancer Biology, Pharmacology and Neuroscience, Meharry Medical College, Nashville, Tennessee, USA
| | - Nicklas Sapp
- Center for AIDS Health Disparities Research, Meharry Medical College, Nashville, Tennessee, USA
- Department of Biochemistry, Cancer Biology, Pharmacology and Neuroscience, Meharry Medical College, Nashville, Tennessee, USA
| | - Prem Prakash
- Center for AIDS Health Disparities Research, Meharry Medical College, Nashville, Tennessee, USA
- Department of Biochemistry, Cancer Biology, Pharmacology and Neuroscience, Meharry Medical College, Nashville, Tennessee, USA
| | - Shalonda Ingram
- Department of Biochemistry, Cancer Biology, Pharmacology and Neuroscience, Meharry Medical College, Nashville, Tennessee, USA
| | - Min Li
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Robert Craigie
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Thomas Hollis
- Department of Biochemistry, Wake Forest School of Medicine, Winston-Salem, North Carolina, USA
| | - Jui Pandhare
- Center for AIDS Health Disparities Research, Meharry Medical College, Nashville, Tennessee, USA
- Department of Microbiology, Immunology, and Physiology, Meharry Medical College, Nashville, Tennessee, USA
- School of Graduate Studies and Research, Meharry Medical College, Nashville, Tennessee, USA
| | - Chandravanu Dash
- Center for AIDS Health Disparities Research, Meharry Medical College, Nashville, Tennessee, USA
- Department of Biochemistry, Cancer Biology, Pharmacology and Neuroscience, Meharry Medical College, Nashville, Tennessee, USA
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Barski MS, Minnell JJ, Hodakova Z, Pye VE, Nans A, Cherepanov P, Maertens GN. Cryo-EM structure of the deltaretroviral intasome in complex with the PP2A regulatory subunit B56γ. Nat Commun 2020; 11:5043. [PMID: 33028863 PMCID: PMC7542444 DOI: 10.1038/s41467-020-18874-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Accepted: 09/15/2020] [Indexed: 01/07/2023] Open
Abstract
Human T-cell lymphotropic virus type 1 (HTLV-1) is a deltaretrovirus and the most oncogenic pathogen. Many of the ~20 million HTLV-1 infected people will develop severe leukaemia or an ALS-like motor disease, unless a therapy becomes available. A key step in the establishment of infection is the integration of viral genetic material into the host genome, catalysed by the retroviral integrase (IN) enzyme. Here, we use X-ray crystallography and single-particle cryo-electron microscopy to determine the structure of the functional deltaretroviral IN assembled on viral DNA ends and bound to the B56γ subunit of its human host factor, protein phosphatase 2 A. The structure reveals a tetrameric IN assembly bound to two molecules of the phosphatase via a conserved short linear motif. Insight into the deltaretroviral intasome and its interaction with the host will be crucial for understanding the pattern of integration events in infected individuals and therefore bears important clinical implications.
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MESH Headings
- Amino Acid Motifs/genetics
- Cloning, Molecular
- Cryoelectron Microscopy
- Crystallography, X-Ray
- DNA, Viral/metabolism
- DNA, Viral/ultrastructure
- Human T-lymphotropic virus 1/enzymology
- Human T-lymphotropic virus 1/genetics
- Human T-lymphotropic virus 1/pathogenicity
- Humans
- Integrases/genetics
- Integrases/metabolism
- Integrases/ultrastructure
- Leukemia-Lymphoma, Adult T-Cell/pathology
- Leukemia-Lymphoma, Adult T-Cell/virology
- Molecular Docking Simulation
- Mutagenesis, Site-Directed
- Paraparesis, Tropical Spastic/pathology
- Paraparesis, Tropical Spastic/virology
- Protein Multimerization
- Protein Phosphatase 2/genetics
- Protein Phosphatase 2/metabolism
- Protein Phosphatase 2/ultrastructure
- Protein Structure, Quaternary
- Recombinant Proteins/genetics
- Recombinant Proteins/metabolism
- Recombinant Proteins/ultrastructure
- Sequence Homology, Amino Acid
- Simian T-lymphotropic virus 1/enzymology
- Simian T-lymphotropic virus 1/genetics
- Single Molecule Imaging
- Viral Proteins/genetics
- Viral Proteins/metabolism
- Viral Proteins/ultrastructure
- Virus Integration
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Affiliation(s)
- Michał S Barski
- Imperial College London, St Mary's Hospital, Department of Infectious Disease, Section of Virology, Norfolk Place, London, W2 1PG, UK
| | - Jordan J Minnell
- Imperial College London, St Mary's Hospital, Department of Infectious Disease, Section of Virology, Norfolk Place, London, W2 1PG, UK
| | - Zuzana Hodakova
- Chromatin Structure and Mobile DNA Laboratory, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
| | - Valerie E Pye
- Chromatin Structure and Mobile DNA Laboratory, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
| | - Andrea Nans
- Structural Biology Science Technology Platform, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
| | - Peter Cherepanov
- Imperial College London, St Mary's Hospital, Department of Infectious Disease, Section of Virology, Norfolk Place, London, W2 1PG, UK
- Chromatin Structure and Mobile DNA Laboratory, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
| | - Goedele N Maertens
- Imperial College London, St Mary's Hospital, Department of Infectious Disease, Section of Virology, Norfolk Place, London, W2 1PG, UK.
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Influence of the amino-terminal sequence on the structure and function of HIV integrase. Retrovirology 2020; 17:28. [PMID: 32867805 PMCID: PMC7457537 DOI: 10.1186/s12977-020-00537-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2020] [Accepted: 08/21/2020] [Indexed: 12/12/2022] Open
Abstract
Background Antiretroviral therapy (ART) can mitigate the morbidity and mortality caused by the human immunodeficiency virus (HIV). Successful development of ART can be accelerated by accurate structural and biochemical data on targets and their responses to inhibitors. One important ART target, HIV integrase (IN), has historically been studied in vitro in a modified form adapted to bacterial overexpression, with a methionine or a longer fusion protein sequence at the N-terminus. In contrast, IN present in viral particles is produced by proteolytic cleavage of the Pol polyprotein, which leaves a phenylalanine at the N-terminus (IN 1F). Inspection of available structures suggested that added residues on the N-terminus might disrupt proper protein folding and formation of multimeric complexes. Results We purified HIV-1 IN 1F1–212 and solved its structure at 2.4 Å resolution, which showed extension of an N-terminal helix compared to the published structure of IN1–212. Full-length IN 1F showed increased in vitro catalytic activity in assays of coupled joining of the two viral DNA ends compared to two IN variants containing additional N-terminal residues. IN 1F was also altered in its sensitivity to inhibitors, showing decreased sensitivity to the strand-transfer inhibitor raltegravir and increased sensitivity to allosteric integrase inhibitors. In solution, IN 1F exists as monomers and dimers, in contrast to other IN preparations which exist as higher-order oligomers. Conclusions The structural, biochemical, and biophysical characterization of IN 1F reveals the conformation of the native HIV-1 IN N-terminus and accompanying unique biochemical and biophysical properties. IN 1F thus represents an improved reagent for use in integration reactions in vitro and the development of antiretroviral agents.
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Passos DO, Li M, Jóźwik IK, Zhao XZ, Santos-Martins D, Yang R, Smith SJ, Jeon Y, Forli S, Hughes SH, Burke TR, Craigie R, Lyumkis D. Structural basis for strand-transfer inhibitor binding to HIV intasomes. Science 2020; 367:810-814. [PMID: 32001521 PMCID: PMC7357238 DOI: 10.1126/science.aay8015] [Citation(s) in RCA: 55] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Accepted: 01/17/2020] [Indexed: 01/21/2023]
Abstract
The HIV intasome is a large nucleoprotein assembly that mediates the integration of a DNA copy of the viral genome into host chromatin. Intasomes are targeted by the latest generation of antiretroviral drugs, integrase strand-transfer inhibitors (INSTIs). Challenges associated with lentiviral intasome biochemistry have hindered high-resolution structural studies of how INSTIs bind to their native drug target. Here, we present high-resolution cryo-electron microscopy structures of HIV intasomes bound to the latest generation of INSTIs. These structures highlight how small changes in the integrase active site can have notable implications for drug binding and design and provide mechanistic insights into why a leading INSTI retains efficacy against a broad spectrum of drug-resistant variants. The data have implications for expanding effective treatments available for HIV-infected individuals.
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Affiliation(s)
- Dario Oliveira Passos
- The Salk Institute for Biological Studies, Laboratory of Genetics, La Jolla, CA, 92037
| | - Min Li
- National Institutes of Health, National Institute of Diabetes and Digestive Diseases, Bethesda, MD, 20892
| | - Ilona K. Jóźwik
- The Salk Institute for Biological Studies, Laboratory of Genetics, La Jolla, CA, 92037
| | - Xue Zhi Zhao
- Center for Cancer Research, National Cancer Institute, Frederick, MD, 21702
| | - Diogo Santos-Martins
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, California, United States of America
| | - Renbin Yang
- National Institutes of Health, National Institute of Diabetes and Digestive Diseases, Bethesda, MD, 20892
| | - Steven J. Smith
- Center for Cancer Research, National Cancer Institute, Frederick, MD, 21702
| | - Youngmin Jeon
- The Salk Institute for Biological Studies, Laboratory of Genetics, La Jolla, CA, 92037
| | - Stefano Forli
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, California, United States of America
| | - Stephen H. Hughes
- Center for Cancer Research, National Cancer Institute, Frederick, MD, 21702
| | - Terrence R. Burke
- Center for Cancer Research, National Cancer Institute, Frederick, MD, 21702
| | - Robert Craigie
- National Institutes of Health, National Institute of Diabetes and Digestive Diseases, Bethesda, MD, 20892
| | - Dmitry Lyumkis
- The Salk Institute for Biological Studies, Laboratory of Genetics, La Jolla, CA, 92037,Correspondence to:
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10
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Li M, Chen X, Wang H, Jurado KA, Engelman AN, Craigie R. A Peptide Derived from Lens Epithelium-Derived Growth Factor Stimulates HIV-1 DNA Integration and Facilitates Intasome Structural Studies. J Mol Biol 2020; 432:2055-2066. [PMID: 32061936 PMCID: PMC7350280 DOI: 10.1016/j.jmb.2020.01.040] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Revised: 01/29/2020] [Accepted: 01/30/2020] [Indexed: 01/26/2023]
Abstract
The low solubility and aggregation properties of HIV-1 integrase (IN) are major obstacles for biochemical and structural studies. The lens epithelium-derived growth factor (LEDGF) is a cellular factor that binds IN and tethers preintegration complexes to chromatin before integration. The LEDGF also stimulates HIV-1 IN DNA strand transfer activity and improves its solubility in vitro. We show that these properties are conferred by a short peptide spanning residues 178 to 197 of the LEDGF that encompasses its AT-hook DNA-binding elements. The peptide stimulates HIV-1 IN activity both in trans and in cis. Fusion of the peptide to either the N- or C-terminus of IN results in maximal stimulation of concerted integration activity and greatly improves the solubility of the protein and nucleoprotein complexes of IN with viral DNA ends (intasomes). High-resolution structures of HIV-1 intasomes are required to understand the mechanism of IN strand transfer inhibitors (INSTIs), which are front-line drugs for the treatment of HIV-1, and how the virus can develop resistance to INSTIs. We have previously determined the structure of the HIV-1 strand transfer complex intasome. The improved biophysical properties of intasomes assembled with LEDGF peptide fusion IN have enabled us to determine the structure of the cleaved synaptic complex intasome, which is the direct target of INSTIs.
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Affiliation(s)
- Min Li
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, USA
| | - Xuemin Chen
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, USA
| | - Huaibin Wang
- NIH Multi-Institute Cryo-EM Facility, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Kellie A Jurado
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute and Department of Medicine, Harvard Medical School, Boston, MA, 02215, USA
| | - Alan N Engelman
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute and Department of Medicine, Harvard Medical School, Boston, MA, 02215, USA
| | - Robert Craigie
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, USA.
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11
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Cai M, Huang Y, Craigie R, Clore GM. A simple protocol for expression of isotope-labeled proteins in Escherichia coli grown in shaker flasks at high cell density. JOURNAL OF BIOMOLECULAR NMR 2019; 73:743-748. [PMID: 31677040 DOI: 10.1007/s10858-019-00285-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Accepted: 10/09/2019] [Indexed: 06/10/2023]
Abstract
Protein expression in E. coli grown in shaker flasks is a routine and pivotal tool in many research laboratories. To maximize protein yields, cells are normally induced in the middle of the linear growth phase, typically at an OD600 of ≤ 1 for cells grown in Luria-Bertani (LB) medium at 37 °C. We recently showed that the E. coli linear growth phase can be extended to higher cell density when cells are cultured under less than optimal conditions such as in minimal medium and/or at lower temperatures. Maximizing the yield of protein per unit volume of culture is important for reducing the costs, especially when isotopically labeling is required. Here, we present a modified minimal medium and a simple protocol that can increase the protein yield up to fourfold in a pH-stabilized LB medium and up to sevenfold in a modified M9+ medium (M9++). When M9++ medium coupled with the high density (OD600 ~ 6) cell growth protocol are used to express uniformly 15N- or 15N/13C-labeled proteins, the amount of 15NH4Cl and 13C6-glucose for a given cell mass is reduced by 50% and ~ 65%, respectively, relative to the traditional low density (OD600 ~ 1) cell growth protocol with M9 medium; the inclusion of 0.1% LB in the minimal medium permits a reduction in the concentration of both the trace element solution and MgCl2, which can cause precipitation. Mass data indicate that inclusion of 0.1% LB does not significantly affect the isotope enrichment level.
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Affiliation(s)
- Mengli Cai
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, 20892-0520, USA
| | - Ying Huang
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, 20892-0520, USA
| | - Robert Craigie
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, 20892-0520, USA.
| | - G Marius Clore
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, 20892-0520, USA.
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12
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Rose KM, Alves Ferreira-Bravo I, Li M, Craigie R, Ditzler MA, Holliger P, DeStefano JJ. Selection of 2'-Deoxy-2'-Fluoroarabino Nucleic Acid (FANA) Aptamers That Bind HIV-1 Integrase with Picomolar Affinity. ACS Chem Biol 2019; 14:2166-2175. [PMID: 31560515 PMCID: PMC7005942 DOI: 10.1021/acschembio.9b00237] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
![]()
Systematic Evolution
of Ligands by Exponential Enrichment (SELEX)
is the iterative process by which nucleic acids that can bind with
high affinity and specificity (termed aptamers) to specific protein
targets are selected. Using a SELEX protocol adapted for Xeno-Nucleic
Acid (XNA) as a suitable substrate for aptamer generation, 2′-fluoroarabinonucleic
acid (FANA) was used to select several related aptamers to HIV-1 integrase
(IN). IN bound FANA aptamers with equilibrium dissociation constants
(KD,app) of ∼50–100 pM in
a buffer with 200 mM NaCl and 6 mM MgCl2. Comparisons to
published HIV-1 IN RNA and DNA aptamers as well as IN genomic binding
partners indicated that FANA aptamers bound more than 2 orders of
magnitude more tightly to IN. Using a combination of RNA folding algorithms
and covariation analysis, all strong binding aptamers demonstrated
a common four-way junction structure, despite significant sequence
variation. IN aptamers were selected from the same starting library
as FA1, a FANA aptamer that binds with pM affinity to HIV-1 Reverse
Transcriptase (RT). It contains a 20-nucleotide 5′ DNA sequence
followed by 59 FANA nucleotides. IN-1.1 (one of the selected aptamers)
potently inhibited IN activity and intasome formation in vitro. Replacing
the FANA nucleotides of IN-1.1 with 2′-fluororibonucleic acid
(F-RNA), which has the same chemical formula but with a ribose rather
than arabinose sugar conformation, dramatically reduced binding, suggesting
that FANA adopts unique structural conformations that promote binding
to HIV-1 IN.
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13
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Engelman AN. Multifaceted HIV integrase functionalities and therapeutic strategies for their inhibition. J Biol Chem 2019; 294:15137-15157. [PMID: 31467082 DOI: 10.1074/jbc.rev119.006901] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Antiretroviral inhibitors that are used to manage HIV infection/AIDS predominantly target three enzymes required for virus replication: reverse transcriptase, protease, and integrase. Although integrase inhibitors were the last among this group to be approved for treating people living with HIV, they have since risen to the forefront of treatment options. Integrase strand transfer inhibitors (INSTIs) are now recommended components of frontline and drug-switch antiretroviral therapy formulations. Integrase catalyzes two successive magnesium-dependent polynucleotidyl transferase reactions, 3' processing and strand transfer, and INSTIs tightly bind the divalent metal ions and viral DNA end after 3' processing, displacing from the integrase active site the DNA 3'-hydroxyl group that is required for strand transfer activity. Although second-generation INSTIs present higher barriers to the development of viral drug resistance than first-generation compounds, the mechanisms underlying these superior barrier profiles are incompletely understood. A separate class of HIV-1 integrase inhibitors, the allosteric integrase inhibitors (ALLINIs), engage integrase distal from the enzyme active site, namely at the binding site for the cellular cofactor lens epithelium-derived growth factor (LEDGF)/p75 that helps to guide integration into host genes. ALLINIs inhibit HIV-1 replication by inducing integrase hypermultimerization, which precludes integrase binding to genomic RNA and perturbs the morphogenesis of new viral particles. Although not yet approved for human use, ALLINIs provide important probes that can be used to investigate the link between HIV-1 integrase and viral particle morphogenesis. Herein, I review the mechanisms of retroviral integration as well as the promises and challenges of using integrase inhibitors for HIV/AIDS management.
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Affiliation(s)
- Alan N Engelman
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, Massachusetts 02215 Department of Medicine, Harvard Medical School, Boston, Massachusetts 02115
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14
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Structural Insights on Retroviral DNA Integration: Learning from Foamy Viruses. Viruses 2019; 11:v11090770. [PMID: 31443391 PMCID: PMC6784120 DOI: 10.3390/v11090770] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Revised: 08/19/2019] [Accepted: 08/20/2019] [Indexed: 12/28/2022] Open
Abstract
Foamy viruses (FV) are retroviruses belonging to the Spumaretrovirinae subfamily. They are non-pathogenic viruses endemic in several mammalian hosts like non-human primates, felines, bovines, and equines. Retroviral DNA integration is a mandatory step and constitutes a prime target for antiretroviral therapy. This activity, conserved among retroviruses and long terminal repeat (LTR) retrotransposons, involves a viral nucleoprotein complex called intasome. In the last decade, a plethora of structural insights on retroviral DNA integration arose from the study of FV. Here, we review the biochemistry and the structural features of the FV integration apparatus and will also discuss the mechanism of action of strand transfer inhibitors.
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15
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Rogers L, Obasa AE, Jacobs GB, Sarafianos SG, Sönnerborg A, Neogi U, Singh K. Structural Implications of Genotypic Variations in HIV-1 Integrase From Diverse Subtypes. Front Microbiol 2018; 9:1754. [PMID: 30116231 PMCID: PMC6083056 DOI: 10.3389/fmicb.2018.01754] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2018] [Accepted: 07/13/2018] [Indexed: 01/02/2023] Open
Abstract
Human immunodeficiency virus type 1 (HIV-1) integrase (IN) integrates viral DNA into the host genome using its 3′-end processing and strand-transfer activities. Due to the importance of HIV-1 IN, it is targeted by the newest class of approved drugs known as integrase strand transfer inhibitors (INSTIs). INSTIs are efficient in maintaining low viral load; however, as with other approved antivirals, resistance mutations emerge in patients receiving INSTI-containing therapy. As INSTIs are becoming increasingly accessible worldwide, it is important to understand the mechanism(s) of INSTI susceptibility. There is strong evidence suggesting differences in the patterns and mechanisms of drug resistance between HIV-1 subtype B, which dominates in United States, Western Europe and Australia, and non-B infections that are most prevalent in countries of Africa and Asia. IN polymorphisms and other genetic differences among diverse subtypes are likely responsible for these different patterns, but lack of a full-length high-resolution structure of HIV-1 IN has been a roadblock in understanding the molecular mechanisms of INSTI resistance and the impact of polymorphisms on therapy outcome. A recently reported full-length medium-resolution cryoEM structure of HIV-1 IN provides insights into understanding the mechanism of integrase function and the impact of genetic variation on the effectiveness of INSTIs. Here we use molecular modeling to explore the structural impact of IN polymorphisms on the IN reaction mechanism and INSTI susceptibility.
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Affiliation(s)
- Leonard Rogers
- Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, MO, United States
| | - Adetayo E Obasa
- Division of Medical Virology, Department of Pathology, Faculty of Medicine and Health Sciences, Stellenbosch University, Stellenbosch, South Africa.,Division of Clinical Microbiology, Department of Laboratory Medicine, Karolinska Institute, Stockholm, Sweden
| | - Graeme B Jacobs
- Division of Medical Virology, Department of Pathology, Faculty of Medicine and Health Sciences, Stellenbosch University, Stellenbosch, South Africa
| | - Stefan G Sarafianos
- Laboratory of Biochemical Pharmacology, Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, United States
| | - Anders Sönnerborg
- Division of Clinical Microbiology, Department of Laboratory Medicine, Karolinska Institute, Stockholm, Sweden.,Division of Infectious Diseases, Department of Medicine Huddinge, Karolinska Institute, Stockholm, Sweden
| | - Ujjwal Neogi
- Division of Clinical Microbiology, Department of Laboratory Medicine, Karolinska Institute, Stockholm, Sweden
| | - Kamalendra Singh
- Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, MO, United States.,Division of Clinical Microbiology, Department of Laboratory Medicine, Karolinska Institute, Stockholm, Sweden.,Department of Molecular Microbiology and Immunology, University of Missouri, Columbia, MO, United States
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16
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Craigie R. Nucleoprotein Intermediates in HIV-1 DNA Integration: Structure and Function of HIV-1 Intasomes. Subcell Biochem 2018; 88:189-210. [PMID: 29900498 DOI: 10.1007/978-981-10-8456-0_9] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Integration of a DNA copy of the viral genome into host DNA is an essential step in the replication cycle of HIV-1 and other retroviruses and is an important therapeutic target for drugs. DNA integration is catalyzed by the viral integrase protein and proceeds through a series of stable nucleoprotein complexes of integrase, viral DNA ends and target DNA. These nucleoprotein complexes are collectively called intasomes. Retroviral intasomes undergo a series of transitions between initial formation and catalysis of the DNA cutting and joining steps of DNA integration. Intasomes, rather than free integrase protein, are the target of currently approved drugs that target HIV-1 DNA integration. High-resolution structures of HIV-1 intasomes are needed to understand their detailed mechanism of action and how HIV-1 may escape by developing resistance. Here, we focus on our current knowledge of the structure and function of HIV-1 intasomes, with reference to related systems as required to put this knowledge in context.
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Affiliation(s)
- Robert Craigie
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA.
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17
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Engelman AN, Cherepanov P. Retroviral intasomes arising. Curr Opin Struct Biol 2017; 47:23-29. [PMID: 28458055 PMCID: PMC5660667 DOI: 10.1016/j.sbi.2017.04.005] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Revised: 04/10/2017] [Accepted: 04/11/2017] [Indexed: 01/26/2023]
Abstract
Retroviral DNA integration takes place in the context of the intasome nucleoprotein complex. X-ray crystal structures of functional spumaviral intasomes were previously revealed to harbor a homotetramer of integrase, and it was generally believed that integrase tetramers catalyzed the integration of other retroviruses. The elucidation of new structures from four different retroviruses over the past year has however revealed this is not the case. The number of integrase molecules required to construct the conserved intasome core structure differs between viral species. While four subunits suffice for spumaviruses, α- and β-retroviruses require eight and the lentiviruses use up to sixteen. Herein we described these alternative architectures, highlighting both evolutionary and structural constraints that result in the different integrase-DNA stoichiometries across Retroviridae.
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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.
| | - Peter Cherepanov
- Chromatin Structure and Mobile DNA, The Francis Crick Institute, London NW1 1AT, UK; Department of Medicine, Imperial College London, St-Mary's Campus, Norfolk Place, London W2 1PG, UK.
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18
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Passos DO, Li M, Yang R, Rebensburg SV, Ghirlando R, Jeon Y, Shkriabai N, Kvaratskhelia M, Craigie R, Lyumkis D. Cryo-EM structures and atomic model of the HIV-1 strand transfer complex intasome. Science 2017; 355:89-92. [PMID: 28059769 DOI: 10.1126/science.aah5163] [Citation(s) in RCA: 135] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Accepted: 12/02/2016] [Indexed: 12/25/2022]
Abstract
Like all retroviruses, HIV-1 irreversibly inserts a viral DNA (vDNA) copy of its RNA genome into host target DNA (tDNA). The intasome, a higher-order nucleoprotein complex composed of viral integrase (IN) and the ends of linear vDNA, mediates integration. Productive integration into host chromatin results in the formation of the strand transfer complex (STC) containing catalytically joined vDNA and tDNA. HIV-1 intasomes have been refractory to high-resolution structural studies. We used a soluble IN fusion protein to facilitate structural studies, through which we present a high-resolution cryo-electron microscopy (cryo-EM) structure of the core tetrameric HIV-1 STC and a higher-order form that adopts carboxyl-terminal domain rearrangements. The distinct STC structures highlight how HIV-1 can use the common retroviral intasome core architecture to accommodate different IN domain modules for assembly.
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Affiliation(s)
- Dario Oliveira Passos
- Laboratory of Genetics and Helmsley Center for Genomic Medicine, The Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Min Li
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Renbin Yang
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Stephanie V Rebensburg
- Center for Retrovirus Research and College of Pharmacy, The Ohio State University, Columbus, OH 43210, USA
| | - Rodolfo Ghirlando
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Youngmin Jeon
- Laboratory of Genetics and Helmsley Center for Genomic Medicine, The Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Nikoloz Shkriabai
- Center for Retrovirus Research and College of Pharmacy, The Ohio State University, Columbus, OH 43210, USA
| | - Mamuka Kvaratskhelia
- Center for Retrovirus Research and College of Pharmacy, The Ohio State University, Columbus, OH 43210, USA
| | - Robert Craigie
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Dmitry Lyumkis
- Laboratory of Genetics and Helmsley Center for Genomic Medicine, The Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA.
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19
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Grawenhoff J, Engelman AN. Retroviral integrase protein and intasome nucleoprotein complex structures. World J Biol Chem 2017; 8:32-44. [PMID: 28289517 PMCID: PMC5329712 DOI: 10.4331/wjbc.v8.i1.32] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Revised: 12/24/2016] [Accepted: 01/14/2017] [Indexed: 02/05/2023] Open
Abstract
Retroviral replication proceeds through the integration of a DNA copy of the viral RNA genome into the host cellular genome, a process that is mediated by the viral integrase (IN) protein. IN catalyzes two distinct chemical reactions: 3’-processing, whereby the viral DNA is recessed by a di- or trinucleotide at its 3’-ends, and strand transfer, in which the processed viral DNA ends are inserted into host chromosomal DNA. Although IN has been studied as a recombinant protein since the 1980s, detailed structural understanding of its catalytic functions awaited high resolution structures of functional IN-DNA complexes or intasomes, initially obtained in 2010 for the spumavirus prototype foamy virus (PFV). Since then, two additional retroviral intasome structures, from the α-retrovirus Rous sarcoma virus (RSV) and β-retrovirus mouse mammary tumor virus (MMTV), have emerged. Here, we briefly review the history of IN structural biology prior to the intasome era, and then compare the intasome structures of PFV, MMTV and RSV in detail. Whereas the PFV intasome is characterized by a tetrameric assembly of IN around the viral DNA ends, the newer structures harbor octameric IN assemblies. Although the higher order architectures of MMTV and RSV intasomes differ from that of the PFV intasome, they possess remarkably similar intasomal core structures. Thus, retroviral integration machineries have adapted evolutionarily to utilize disparate IN elements to construct convergent intasome core structures for catalytic function.
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20
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Guan R, Aiyer S, Cote ML, Xiao R, Jiang M, Acton TB, Roth MJ, Montelione GT. X-ray crystal structure of the N-terminal region of Moloney murine leukemia virus integrase and its implications for viral DNA recognition. Proteins 2017; 85:647-656. [PMID: 28066922 DOI: 10.1002/prot.25245] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Revised: 11/15/2016] [Accepted: 11/23/2016] [Indexed: 01/26/2023]
Abstract
The retroviral integrase (IN) carries out the integration of a dsDNA copy of the viral genome into the host DNA, an essential step for viral replication. All IN proteins have three general domains, the N-terminal domain (NTD), the catalytic core domain, and the C-terminal domain. The NTD includes an HHCC zinc finger-like motif, which is conserved in all retroviral IN proteins. Two crystal structures of Moloney murine leukemia virus (M-MuLV) IN N-terminal region (NTR) constructs that both include an N-terminal extension domain (NED, residues 1-44) and an HHCC zinc-finger NTD (residues 45-105), in two crystal forms are reported. The structures of IN NTR constructs encoding residues 1-105 (NTR1-105 ) and 8-105 (NTR8-105 ) were determined at 2.7 and 2.15 Å resolution, respectively and belong to different space groups. While both crystal forms have similar protomer structures, NTR1-105 packs as a dimer and NTR8-105 packs as a tetramer in the asymmetric unit. The structure of the NED consists of three anti-parallel β-strands and an α-helix, similar to the NED of prototype foamy virus (PFV) IN. These three β-strands form an extended β-sheet with another β-strand in the HHCC Zn2+ binding domain, which is a unique structural feature for the M-MuLV IN. The HHCC Zn2+ binding domain structure is similar to that in HIV and PFV INs, with variations within the loop regions. Differences between the PFV and MLV IN NEDs localize at regions identified to interact with the PFV LTR and are compared with established biochemical and virological data for M-MuLV. Proteins 2017; 85:647-656. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Rongjin Guan
- Center for Advanced Biotechnology and Medicine, Rutgers, The State University of New Jersey, Piscataway, New Jersey, 08854.,Northeast Structural Genomics Consortium, Rutgers, The State University of New Jersey, Piscataway, New Jersey, 08854.,Department of Molecular Biology and Biochemistry, Rutgers, The State University of New Jersey, Piscataway, New Jersey, 08854
| | - Sriram Aiyer
- Department of Pharmacology, Robert Wood Johnson Medical School, Rutgers, The State University of New Jersey, Piscataway, New Jersey, 08854
| | - Marie L Cote
- Department of Biochemistry, Robert Wood Johnson Medical School, UMDNJ, Piscataway, New Jersey, 08854
| | - Rong Xiao
- Center for Advanced Biotechnology and Medicine, Rutgers, The State University of New Jersey, Piscataway, New Jersey, 08854.,Northeast Structural Genomics Consortium, Rutgers, The State University of New Jersey, Piscataway, New Jersey, 08854.,Department of Molecular Biology and Biochemistry, Rutgers, The State University of New Jersey, Piscataway, New Jersey, 08854
| | - Mei Jiang
- Center for Advanced Biotechnology and Medicine, Rutgers, The State University of New Jersey, Piscataway, New Jersey, 08854.,Northeast Structural Genomics Consortium, Rutgers, The State University of New Jersey, Piscataway, New Jersey, 08854.,Department of Molecular Biology and Biochemistry, Rutgers, The State University of New Jersey, Piscataway, New Jersey, 08854
| | - Thomas B Acton
- Center for Advanced Biotechnology and Medicine, Rutgers, The State University of New Jersey, Piscataway, New Jersey, 08854.,Northeast Structural Genomics Consortium, Rutgers, The State University of New Jersey, Piscataway, New Jersey, 08854.,Department of Molecular Biology and Biochemistry, Rutgers, The State University of New Jersey, Piscataway, New Jersey, 08854
| | - Monica J Roth
- Department of Pharmacology, Robert Wood Johnson Medical School, Rutgers, The State University of New Jersey, Piscataway, New Jersey, 08854
| | - Gaetano T Montelione
- Center for Advanced Biotechnology and Medicine, Rutgers, The State University of New Jersey, Piscataway, New Jersey, 08854.,Northeast Structural Genomics Consortium, Rutgers, The State University of New Jersey, Piscataway, New Jersey, 08854.,Department of Molecular Biology and Biochemistry, Rutgers, The State University of New Jersey, Piscataway, New Jersey, 08854.,Department of Biochemistry, Robert Wood Johnson Medical School, UMDNJ, Piscataway, New Jersey, 08854
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21
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Ballandras-Colas A, Maskell DP, Serrao E, Locke J, Swuec P, Jónsson SR, Kotecha A, Cook NJ, Pye VE, Taylor IA, Andrésdóttir V, Engelman AN, Costa A, Cherepanov P. A supramolecular assembly mediates lentiviral DNA integration. Science 2017; 355:93-95. [PMID: 28059770 PMCID: PMC5321526 DOI: 10.1126/science.aah7002] [Citation(s) in RCA: 80] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Accepted: 12/01/2016] [Indexed: 12/16/2022]
Abstract
Retroviral integrase (IN) functions within the intasome nucleoprotein complex to catalyze insertion of viral DNA into cellular chromatin. Using cryo-electron microscopy, we now visualize the functional maedi-visna lentivirus intasome at 4.9 angstrom resolution. The intasome comprises a homo-hexadecamer of IN with a tetramer-of-tetramers architecture featuring eight structurally distinct types of IN protomers supporting two catalytically competent subunits. The conserved intasomal core, previously observed in simpler retroviral systems, is formed between two IN tetramers, with a pair of C-terminal domains from flanking tetramers completing the synaptic interface. Our results explain how HIV-1 IN, which self-associates into higher-order multimers, can form a functional intasome, reconcile the bulk of early HIV-1 IN biochemical and structural data, and provide a lentiviral platform for design of HIV-1 IN inhibitors.
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Affiliation(s)
| | - Daniel P. Maskell
- Chromatin Structure and Mobile DNA, The Francis Crick Institute, London, NW1 1AT, UK
| | - Erik Serrao
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, MA 02215, USA
- Department of Medicine, Harvard Medical School, Boston, MA 02115, USA
| | - Julia Locke
- Macromolecular Machines Laboratory, The Francis Crick Institute, London, NW1 1AT, UK
| | - Paolo Swuec
- Macromolecular Machines Laboratory, The Francis Crick Institute, London, NW1 1AT, UK
| | - Stefán R. Jónsson
- Institute for Experimental Pathology, University of Iceland, Keldur, 112 Reykjavik, Iceland
| | - Abhay Kotecha
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, OX3 7BN, UK
| | - Nicola J. Cook
- Chromatin Structure and Mobile DNA, The Francis Crick Institute, London, NW1 1AT, UK
| | - Valerie E. Pye
- Chromatin Structure and Mobile DNA, The Francis Crick Institute, London, NW1 1AT, UK
| | - Ian A. Taylor
- Macromolecular Structure Laboratory, The Francis Crick Institute, London, NW1 1AT, UK
| | - Valgerdur Andrésdóttir
- Institute for Experimental Pathology, University of Iceland, Keldur, 112 Reykjavik, Iceland
| | - 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
| | - Alessandro Costa
- Macromolecular Machines Laboratory, The Francis Crick Institute, London, NW1 1AT, UK
| | - Peter Cherepanov
- Chromatin Structure and Mobile DNA, The Francis Crick Institute, London, NW1 1AT, UK
- Division of Medicine, Imperial College London, W2 1PG, UK
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22
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Turaga G, Edmondson SP, Smith K, Shriver JW. Insights into the Structure of Sulfolobus Nucleoid Using Engineered Sac7d Dimers with a Defined Orientation. Biochemistry 2016; 55:6230-6237. [PMID: 27766846 DOI: 10.1021/acs.biochem.6b00810] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The structure of Archaeal chromatin or nucleoid is believed to have characteristics similar to that found in both eukaryotes and bacteria. Recent comparative studies have suggested that DNA compaction in Archaea requires a bridging protein (e.g., Alba) along with either a wrapping protein (e.g., a histone) or a bending protein such as Sac7d. While X-ray crystal structures demonstrate that Sac7d binds as a monomer to create a significant kink in duplex DNA, the structure of a multiprotein-DNA complex has not been established. Using cross-linked dimers of Sac7d with a defined orientation, we present evidence that indicates that Sac7d is able to largely coat duplex DNA in vivo by binding in alternating head-to-head and tail-to-tail orientations. Although each Sac7d monomer promotes a significant kink of nearly 70°, coated DNA is expected to be largely extended because of compensation of repetitive kinks with helical symmetry.
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Affiliation(s)
- Gokul Turaga
- Departments of Chemistry and Biological Sciences, University of Alabama in Huntsville , Huntsville, Alabama 35899, United States
| | - Stephen P Edmondson
- Departments of Chemistry and Biological Sciences, University of Alabama in Huntsville , Huntsville, Alabama 35899, United States
| | - Kelley Smith
- Departments of Chemistry and Biological Sciences, University of Alabama in Huntsville , Huntsville, Alabama 35899, United States
| | - John W Shriver
- Departments of Chemistry and Biological Sciences, University of Alabama in Huntsville , Huntsville, Alabama 35899, United States
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23
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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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24
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Li M, Lin S, Craigie R. Outer domains of integrase within retroviral intasomes are dispensible for catalysis of DNA integration. Protein Sci 2015; 25:472-8. [PMID: 26537415 DOI: 10.1002/pro.2837] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Revised: 10/28/2015] [Accepted: 10/30/2015] [Indexed: 12/16/2022]
Abstract
Retroviral DNA integration is mediated by nucleoprotein complexes (intasomes) comprising a pair of viral DNA ends synapsed by a tetramer of integrase. Current integrase inhibitors act on intasomes rather than free integrase protein. Structural and functional studies of intasomes are essential to understand their mechanism of action and how the virus can escape by mutation. To date, prototype foamy virus (PFV) is the only retrovirus for which high-resolution structures of intasomes have been determined. In the PFV intasome structure, only the core domains of the outer subunits are ordered; the N-terminal domain, C-terminal domain, and N-terminal extension domain are disordered. Are these "missing domains" required for function or are they dispensable? We have devised a strategy to assemble "hetero-intasomes" in which the outer domains are not present as a tool to assess the functional role of the missing domains for catalysis of integration. We find that the disordered domains of outer subunits are not required for intasome assembly or catalytic activity as catalytic core domains can substitute for the outer subunits in the case of both PFV and HIV-1 intasomes.
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Affiliation(s)
- Min Li
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, 20892
| | - Shiqiang Lin
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, 20892
| | - Robert Craigie
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, 20892
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25
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Huet S, Gorre H, Perrocheau A, Picot J, Cinier M. Use of the Nanofitin Alternative Scaffold as a GFP-Ready Fusion Tag. PLoS One 2015; 10:e0142304. [PMID: 26539718 PMCID: PMC4634965 DOI: 10.1371/journal.pone.0142304] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Accepted: 10/19/2015] [Indexed: 11/26/2022] Open
Abstract
With the continuous diversification of recombinant DNA technologies, the possibilities for new tailor-made protein engineering have extended on an on-going basis. Among these strategies, the use of the green fluorescent protein (GFP) as a fusion domain has been widely adopted for cellular imaging and protein localization. Following the lead of the direct head-to-tail fusion of GFP, we proposed to provide additional features to recombinant proteins by genetic fusion of artificially derived binders. Thus, we reported a GFP-ready fusion tag consisting of a small and robust fusion-friendly anti-GFP Nanofitin binding domain as a proof-of-concept. While limiting steric effects on the carrier, the GFP-ready tag allows the capture of GFP or its blue (BFP), cyan (CFP) and yellow (YFP) alternatives. Here, we described the generation of the GFP-ready tag from the selection of a Nanofitin variant binding to the GFP and its spectral variants with a nanomolar affinity, while displaying a remarkable folding stability, as demonstrated by its full resistance upon thermal sterilization process or the full chemical synthesis of Nanofitins. To illustrate the potential of the Nanofitin-based tag as a fusion partner, we compared the expression level in Escherichia coli and activity profile of recombinant human tumor necrosis factor alpha (TNFα) constructs, fused to a SUMO or GFP-ready tag. Very similar expression levels were found with the two fusion technologies. Both domains of the GFP-ready tagged TNFα were proved fully active in ELISA and interferometry binding assays, allowing the simultaneous capture by an anti-TNFα antibody and binding to the GFP, and its spectral mutants. The GFP-ready tag was also shown inert in a L929 cell based assay, demonstrating the potent TNFα mediated apoptosis induction by the GFP-ready tagged TNFα. Eventually, we proposed the GFP-ready tag as a versatile capture and labeling system in addition to expected applications of anti-GFP Nanofitins (as illustrated with previously described state-of-the-art anti-GFP binders applied to living cells and in vitro applications). Through a single fusion domain, the GFP-ready tagged proteins benefit from subsequent customization within a wide range of fluorescence spectra upon indirect binding of a chosen GFP variant.
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