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Kleinpeter A, Mallery DL, Renner N, Albecka A, Klarhof JO, Freed EO, James LC. HIV-1 adapts to lost IP6 coordination through second-site mutations that restore conical capsid assembly. Nat Commun 2024; 15:8017. [PMID: 39271696 PMCID: PMC11399258 DOI: 10.1038/s41467-024-51971-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2024] [Accepted: 08/20/2024] [Indexed: 09/15/2024] Open
Abstract
The HIV-1 capsid is composed of capsid (CA) protein hexamers and pentamers (capsomers) that contain a central pore hypothesised to regulate capsid assembly and facilitate nucleotide import early during post-infection. These pore functions are mediated by two positively charged rings created by CA Arg-18 (R18) and Lys-25 (K25). Here we describe the forced evolution of viruses containing mutations in R18 and K25. Whilst R18 mutants fail to replicate, K25A viruses acquire compensating mutations that restore nearly wild-type replication fitness. These compensating mutations, which rescue reverse transcription and infection without reintroducing lost pore charges, map to three adaptation hot-spots located within and between capsomers. The second-site suppressor mutations act by restoring the formation of pentamers lost upon K25 mutation, enabling closed conical capsid assembly both in vitro and inside virions. These results indicate that there is no intrinsic requirement for K25 in either nucleotide import or capsid assembly. We propose that whilst HIV-1 must maintain a precise hexamer:pentamer equilibrium for proper capsid assembly, compensatory mutations can tune this equilibrium to restore fitness lost by mutation of the central pore.
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Affiliation(s)
- Alex Kleinpeter
- Virus-Cell Interaction Section, HIV Dynamics and Replication Program, Center for Cancer Research, National Cancer Institute, Frederick, MD, 21702-1201, USA.
| | - Donna L Mallery
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK
| | - Nadine Renner
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK
| | - Anna Albecka
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK
| | - J Ole Klarhof
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK
| | - Eric O Freed
- Virus-Cell Interaction Section, HIV Dynamics and Replication Program, Center for Cancer Research, National Cancer Institute, Frederick, MD, 21702-1201, USA.
| | - Leo C James
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK.
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Papa G, Albecka A, Mallery D, Vaysburd M, Renner N, James LC. IP6-stabilised HIV capsids evade cGAS/STING-mediated host immune sensing. EMBO Rep 2023; 24:e56275. [PMID: 36970882 PMCID: PMC10157305 DOI: 10.15252/embr.202256275] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Revised: 03/06/2023] [Accepted: 03/10/2023] [Indexed: 03/29/2023] Open
Abstract
HIV-1 uses inositol hexakisphosphate (IP6) to build a metastable capsid capable of delivering its genome into the host nucleus. Here, we show that viruses that are unable to package IP6 lack capsid protection and are detected by innate immunity, resulting in the activation of an antiviral state that inhibits infection. Disrupting IP6 enrichment results in defective capsids that trigger cytokine and chemokine responses during infection of both primary macrophages and T-cell lines. Restoring IP6 enrichment with a single mutation rescues the ability of HIV-1 to infect cells without being detected. Using a combination of capsid mutants and CRISPR-derived knockout cell lines for RNA and DNA sensors, we show that immune sensing is dependent upon the cGAS-STING axis and independent of capsid detection. Sensing requires the synthesis of viral DNA and is prevented by reverse transcriptase inhibitors or reverse transcriptase active-site mutation. These results demonstrate that IP6 is required to build capsids that can successfully transit the cell and avoid host innate immune sensing.
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Affiliation(s)
- Guido Papa
- MRC Laboratory of Molecular Biology, Protein & Nucleic Acid DivisionCambridgeUK
| | - Anna Albecka
- MRC Laboratory of Molecular Biology, Protein & Nucleic Acid DivisionCambridgeUK
| | - Donna Mallery
- MRC Laboratory of Molecular Biology, Protein & Nucleic Acid DivisionCambridgeUK
| | - Marina Vaysburd
- MRC Laboratory of Molecular Biology, Protein & Nucleic Acid DivisionCambridgeUK
| | - Nadine Renner
- MRC Laboratory of Molecular Biology, Protein & Nucleic Acid DivisionCambridgeUK
| | - Leo C James
- MRC Laboratory of Molecular Biology, Protein & Nucleic Acid DivisionCambridgeUK
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Direct Capsid Labeling of Infectious HIV-1 by Genetic Code Expansion Allows Detection of Largely Complete Nuclear Capsids and Suggests Nuclear Entry of HIV-1 Complexes via Common Routes. mBio 2022; 13:e0195922. [PMID: 35972146 PMCID: PMC9600849 DOI: 10.1128/mbio.01959-22] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The cone-shaped mature HIV-1 capsid is the main orchestrator of early viral replication. After cytosolic entry, it transports the viral replication complex along microtubules toward the nucleus. While it was initially believed that the reverse transcribed genome is released from the capsid in the cytosol, recent observations indicate that a high amount of capsid protein (CA) remains associated with subviral complexes during import through the nuclear pore complex (NPC). Observation of postentry events via microscopic detection of HIV-1 CA is challenging, since epitope shielding limits immunodetection and the genetic fragility of CA hampers direct labeling approaches. Here, we present a minimally invasive strategy based on genetic code expansion and click chemistry that allows for site-directed fluorescent labeling of HIV-1 CA, while retaining virus morphology and infectivity. Thereby, we could directly visualize virions and subviral complexes using advanced microscopy, including nanoscopy and correlative imaging. Quantification of signal intensities of subviral complexes revealed an amount of CA associated with nuclear complexes in HeLa-derived cells and primary T cells consistent with a complete capsid and showed that treatment with the small molecule inhibitor PF74 did not result in capsid dissociation from nuclear complexes. Cone-shaped objects detected in the nucleus by electron tomography were clearly identified as capsid-derived structures by correlative microscopy. High-resolution imaging revealed dose-dependent clustering of nuclear capsids, suggesting that incoming particles may follow common entry routes.
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Gruenke PR, Aneja R, Welbourn S, Ukah OB, Sarafianos SG, Burke DH, Lange MJ. Selection and identification of an RNA aptamer that specifically binds the HIV-1 capsid lattice and inhibits viral replication. Nucleic Acids Res 2022; 50:1701-1717. [PMID: 35018437 PMCID: PMC8860611 DOI: 10.1093/nar/gkab1293] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Revised: 11/23/2021] [Accepted: 12/16/2021] [Indexed: 01/25/2023] Open
Abstract
The HIV-1 capsid core participates in several replication processes. The mature capsid core is a lattice composed of capsid (CA) monomers thought to assemble first into CA dimers, then into ∼250 CA hexamers and 12 CA pentamers. CA assembly requires conformational flexibility of each unit, resulting in the presence of unique, solvent-accessible surfaces. Significant advances have improved our understanding of the roles of the capsid core in replication; however, the contributions of individual CA assembly forms remain unclear and there are limited tools available to evaluate these forms in vivo. Here, we have selected aptamers that bind CA lattice tubes. We describe aptamer CA15-2, which selectively binds CA lattice, but not CA monomer or CA hexamer, suggesting that it targets an interface present and accessible only on CA lattice. CA15-2 does not compete with PF74 for binding, indicating that it likely binds a non-overlapping site. Furthermore, CA15-2 inhibits HIV-1 replication when expressed in virus producer cells, but not target cells, suggesting that it binds a biologically-relevant site during virus production that is either not accessible during post-entry replication steps or is accessible but unaltered by aptamer binding. Importantly, CA15-2 represents the first aptamer that specifically recognizes the HIV-1 CA lattice.
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Affiliation(s)
- Paige R Gruenke
- Department of Biochemistry, University of Missouri, Columbia, MO 65211, USA.,Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA
| | - Rachna Aneja
- Department of Molecular Microbiology & Immunology, School of Medicine, University of Missouri, Columbia, MO 65211, USA
| | - Sarah Welbourn
- Emory Vaccine Center and Yerkes National Primate Research Center, Emory University, Atlanta, GA 30329, USA
| | - Obiaara B Ukah
- Department of Molecular Microbiology & Immunology, School of Medicine, University of Missouri, Columbia, MO 65211, USA
| | - Stefan G Sarafianos
- Laboratory of Biochemical Pharmacology, Department of Pediatrics, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Donald H Burke
- Department of Biochemistry, University of Missouri, Columbia, MO 65211, USA.,Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA.,Department of Molecular Microbiology & Immunology, School of Medicine, University of Missouri, Columbia, MO 65211, USA
| | - Margaret J Lange
- Department of Molecular Microbiology & Immunology, School of Medicine, University of Missouri, Columbia, MO 65211, USA
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Christensen DE, Ganser-Pornillos BK, Johnson JS, Pornillos O, Sundquist WI. Reconstitution and visualization of HIV-1 capsid-dependent replication and integration in vitro. Science 2020; 370:eabc8420. [PMID: 33033190 PMCID: PMC8022914 DOI: 10.1126/science.abc8420] [Citation(s) in RCA: 87] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2020] [Accepted: 07/31/2020] [Indexed: 12/18/2022]
Abstract
During the first half of the viral life cycle, HIV-1 reverse transcribes its RNA genome and integrates the double-stranded DNA copy into a host cell chromosome. Despite progress in characterizing and inhibiting these processes, in situ mechanistic and structural studies remain challenging. This is because these operations are executed by individual viral preintegration complexes deep within cells. We therefore reconstituted and imaged the early stages of HIV-1 replication in a cell-free system. HIV-1 cores released from permeabilized virions supported efficient, capsid-dependent endogenous reverse transcription to produce double-stranded DNA genomes, which sometimes looped out from ruptured capsid walls. Concerted integration of both viral DNA ends into a target plasmid then proceeded in a cell extract-dependent reaction. This reconstituted system uncovers the role of the capsid in templating replication.
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Affiliation(s)
- Devin E Christensen
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
| | - Barbie K Ganser-Pornillos
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA 22903, USA
| | - Jarrod S Johnson
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
| | - Owen Pornillos
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA 22903, USA.
| | - Wesley I Sundquist
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT 84112, USA.
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