101
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Saito A, Sultana T, Ode H, Nohata K, Samune Y, Nakayama EE, Iwatani Y, Shioda T. The 4th and 112th Residues of Viral Capsid Cooperatively Modulate Capsid-CPSF6 Interactions of HIV-1. AIDS Res Hum Retroviruses 2020; 36:513-521. [PMID: 31941344 PMCID: PMC7262650 DOI: 10.1089/aid.2019.0250] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Binding of HIV-1 capsid (CA) to cleavage and polyadenylation specificity factor 6 (CPSF6) is hypothesized to provide a significant fitness advantage to in vivo viral replication, explaining why CA-CPSF6 interactions are strictly conserved in primate lentiviruses. We recently identified a Q4R mutation in CA after propagation of an interferon (IFN)-β-hypersensitive CA mutant, RGDA/Q112D (H87R, A88G, P90D, P93A and Q112D) virus, in IFN-β-treated cells. The Q4R substitution conferred significant IFN-β resistance to the RGDA/Q112D virus by affecting several properties of the virus, including the sensitivity to myxovirus resistance protein B (MxB), the kinetics of reverse transcription, and the initiation of uncoating. Notably, the Q4R substitution restored the CPSF6 interaction of the RGDA/Q112D virus. To better understand how the Q4R substitution modulated the CA-CPSF6 interaction, we generated a series of CA mutants harboring substitutions at the 4th and 112th residues. In contrast to the effect in the RGDA/Q112D background, the Q4R substitution diminished CA-CPSF6 interaction in an otherwise wild-type virus. Our genetic and structural analyses revealed that while either the Q4R or Q112D substitution impaired CA-CPSF6 interaction, the combination of these substitutions restored this interaction. These results suggest that the 4th and 112th residues in HIV-1 CA cooperatively modulate CA-CPSF6 interactions, further highlighting the tremendous levels of plasticity in primate lentivirus CA, which is one of the barriers to antiretroviral therapy in HIV-1-infected individuals.
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Affiliation(s)
- Akatsuki Saito
- Research Institute for Microbial Diseases, Osaka University, Osaka, Japan
| | - Tahmina Sultana
- Research Institute for Microbial Diseases, Osaka University, Osaka, Japan
| | - Hirotaka Ode
- Clinical Research Center, National Hospital Organization Nagoya Medical Center, Nagoya, Japan
| | - Kyotaro Nohata
- Research Institute for Microbial Diseases, Osaka University, Osaka, Japan
| | - Yoshihiro Samune
- Research Institute for Microbial Diseases, Osaka University, Osaka, Japan
| | - Emi E. Nakayama
- Research Institute for Microbial Diseases, Osaka University, Osaka, Japan
| | - Yasumasa Iwatani
- Clinical Research Center, National Hospital Organization Nagoya Medical Center, Nagoya, Japan
- Division of Basic Medicine, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Tatsuo Shioda
- Research Institute for Microbial Diseases, Osaka University, Osaka, Japan
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102
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Dharan A, Bachmann N, Talley S, Zwikelmaier V, Campbell EM. Nuclear pore blockade reveals that HIV-1 completes reverse transcription and uncoating in the nucleus. Nat Microbiol 2020; 5:1088-1095. [PMID: 32483230 PMCID: PMC9286700 DOI: 10.1038/s41564-020-0735-8] [Citation(s) in RCA: 111] [Impact Index Per Article: 27.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Accepted: 05/05/2020] [Indexed: 11/09/2022]
Abstract
Retroviral infection involves the reverse transcription of the viral RNA genome into DNA, which is subsequently integrated into the host cell genome. HIV-1 and other lentiviruses are able to mediate the infection of non-dividing cells through the ability of the capsid (CA) protein 1 to engage the cellular nuclear import pathways of the target cell and mediate their nuclear translocation through components of the nuclear pore complex (NPC) 2–4. Although recent studies have observed the presence of capsid in the nucleus during infection5–8, reverse transcription and disassembly of the viral core have conventionally been considered to be cytoplasmic events. Here, we use an inducible nuclear pore blockade to monitor the kinetics of HIV-1 nuclear import and define the biochemical staging of these steps of infection. Surprisingly, we observe that nuclear import occurs with relatively rapid kinetics (<5 hours) and precedes the completion of reverse transcription in target cells, demonstrating that reverse transcription completes in the nucleus. We also observe that HIV-1 remains susceptible to a capsid destabilizing compound PF74 following nuclear import, revealing that uncoating completes in the nucleus. We also observe that certain CA mutants are insensitive to a Nup62 mediated nuclear pore blockade in cells which potently block infection by wild type CA, demonstrating that HIV-1 can utilize distinct nuclear import pathways during infection. These studies collectively define the spatiotemporal staging of critical steps of HIV-1 infection and provide an experimental system to separate and thereby define the cytoplasmic and nuclear stages of infection by other viruses.
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Affiliation(s)
- Adarsh Dharan
- Department of Microbiology and Immunology, Stritch School of Medicine, Loyola University Chicago, Chicago, IL, USA
| | - Niklas Bachmann
- Department of Microbiology and Immunology, Stritch School of Medicine, Loyola University Chicago, Chicago, IL, USA
| | - Sarah Talley
- Integrative Cell Biology Program, Stritch School of Medicine, Loyola University Chicago, Chicago, IL, USA
| | - Virginia Zwikelmaier
- Department of Microbiology and Immunology, Stritch School of Medicine, Loyola University Chicago, Chicago, IL, USA
| | - Edward M Campbell
- Department of Microbiology and Immunology, Stritch School of Medicine, Loyola University Chicago, Chicago, IL, USA. .,Integrative Cell Biology Program, Stritch School of Medicine, Loyola University Chicago, Chicago, IL, USA.
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103
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Remodeling of the Core Leads HIV-1 Preintegration Complex into the Nucleus of Human Lymphocytes. J Virol 2020; 94:JVI.00135-20. [PMID: 32238582 PMCID: PMC7269431 DOI: 10.1128/jvi.00135-20] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Accepted: 03/24/2020] [Indexed: 02/08/2023] Open
Abstract
How the reverse-transcribed genome reaches the host nucleus remains a main open question related to the infectious cycle of HIV-1. The HIV-1 core has a size of ∼100 nm, largely exceeding that of the NPC channel (∼39 nm). Thus, a rearrangement of the viral CA protein organization is required to achieve an effective nuclear translocation. The mechanism of this process remains undefined due to the lack of a technology capable of visualizing potential CA subcomplexes in association with the viral DNA in the nucleus of HIV-1-infected cells. By the means of state-of-the-art technologies (HIV-1 ANCHOR system combined with CLEM), our study shows that remodeled viral complexes retain multiple CA proteins but not an intact core or only a single CA monomer. These viral CA complexes associated with the retrotranscribed DNA can be observed inside the nucleus, and they represent a potential PIC. Thus, our study shed light on critical early steps characterizing HIV-1 infection, thereby revealing novel, therapeutically exploitable points of intervention. Furthermore, we developed and provided a powerful tool enabling direct, specific, and high-resolution visualization of intracellular and intranuclear HIV-1 subviral structures. Retroviral replication proceeds through obligate integration of the viral DNA into the host genome. In particular, for the HIV-1 genome to enter the nucleus, it must be led through the nuclear pore complex (NPC). During the HIV-1 cytoplasmic journey, the viral core acts as a shell to protect the viral genetic material from antiviral sensors and ensure an adequate environment for reverse transcription. However, the relatively narrow size of the nuclear pore channel requires that the HIV-1 core is reshaped into a structure that fits the pore. On the other hand, the organization of the viral CA proteins that remain associated with the preintegration complex (PIC) during and after nuclear translocation is still enigmatic. In this study, we analyzed the progressive organizational changes of viral CA proteins within the cytoplasm and the nucleus by immunogold labeling. Furthermore, we set up a novel technology, HIV-1 ANCHOR, which enables the specific detection of the retrotranscribed DNA by fluorescence microscopy, thereby offering the opportunity to uncover the architecture of the potential HIV-1 PIC. Thus, we combined the immunoelectron microscopy and ANCHOR technologies to reveal the presence of DNA- and CA-positive complexes by correlated light and electron microscopy (CLEM). During and after nuclear translocation, HIV-1 appears as a complex of viral DNA decorated by multiple viral CA proteins remodeled in a pearl necklace-like shape. Thus, we could describe how CA proteins are reshaped around the viral DNA to permit the entrance of the HIV-1 in the nucleus. This particular CA protein complex composed of the integrase and the retrotranscribed DNA leads the HIV-1 genome inside the host nucleus. Our findings contribute to the understanding of the early steps of HIV-1 infection and provide new insights into the organization of HIV-1 CA proteins during and after viral nuclear entry. Of note, we are now able to visualize the viral DNA in viral complexes, opening up new perspectives for future studies on virus’s fate in the cell nucleus. IMPORTANCE How the reverse-transcribed genome reaches the host nucleus remains a main open question related to the infectious cycle of HIV-1. The HIV-1 core has a size of ∼100 nm, largely exceeding that of the NPC channel (∼39 nm). Thus, a rearrangement of the viral CA protein organization is required to achieve an effective nuclear translocation. The mechanism of this process remains undefined due to the lack of a technology capable of visualizing potential CA subcomplexes in association with the viral DNA in the nucleus of HIV-1-infected cells. By the means of state-of-the-art technologies (HIV-1 ANCHOR system combined with CLEM), our study shows that remodeled viral complexes retain multiple CA proteins but not an intact core or only a single CA monomer. These viral CA complexes associated with the retrotranscribed DNA can be observed inside the nucleus, and they represent a potential PIC. Thus, our study shed light on critical early steps characterizing HIV-1 infection, thereby revealing novel, therapeutically exploitable points of intervention. Furthermore, we developed and provided a powerful tool enabling direct, specific, and high-resolution visualization of intracellular and intranuclear HIV-1 subviral structures.
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104
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Borini Etichetti CM, Tenaglia A, Arroyo MN, Girardini JE. Expression of zebrafish cpsf6 in embryogenesis and role of protein domains on subcellular localization. Gene Expr Patterns 2020; 36:119114. [PMID: 32330562 DOI: 10.1016/j.gep.2020.119114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Revised: 04/12/2020] [Accepted: 04/20/2020] [Indexed: 10/24/2022]
Abstract
CPSF6 is a component of the CFIm complex, involved in mRNA 3'end processing. Despite increasing interest on this protein as a consequence of proposed roles in cancer and HIV infection, several aspects of CPSF6 biological function are poorly understood. In this work we studied the expression of the zebrafish ortholog cpsf6 in early stages of embryo development. Quantitative RT-PCR studies showed that zebrafish cpsf6 mRNA is maternally inherited and that its concentration markedly decreases during early development. We found a generalized distribution of cpsf6 mRNA in early stages through whole mount hybridization experiments. By performing Western blot, we also found a decrease in zebrafish Cpsf6 levels during development. Our analysis of the subcellular localization of this protein using a heterologous system showed a distinct pattern characterized by the presence of nuclear foci. We also studied the relevance of different protein domains on subcellular localization, showing that the C-terminal domain is critical for nuclear localization. Collectively, our results showed that cpsf6 expression changes during early development and that the subcellular localization of the protein is similar to that of the human ortholog.
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Affiliation(s)
- Carla M Borini Etichetti
- Instituto de Fisiología Experimental (IFISE), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Rosario, Argentina
| | - Albano Tenaglia
- Instituto de Biología Molecular y Celular de Rosario (IBR), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Rosario, Argentina
| | - María Nicol Arroyo
- Instituto de Biología Molecular y Celular de Rosario (IBR), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Rosario, Argentina
| | - Javier E Girardini
- Instituto de Inmunología Clínica y Experimental de Rosario (IDICER), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Rosario, Argentina.
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105
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PF74 and Its Novel Derivatives Stabilize Hexameric Lattice of HIV-1 Mature-Like Particles. Molecules 2020; 25:molecules25081895. [PMID: 32325987 PMCID: PMC7221806 DOI: 10.3390/molecules25081895] [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: 03/19/2020] [Revised: 04/09/2020] [Accepted: 04/15/2020] [Indexed: 01/23/2023] Open
Abstract
A major structural retroviral protein, capsid protein (CA), is able to oligomerize into two different hexameric lattices, which makes this protein a key component for both the early and late stages of HIV-1 replication. During the late stage, the CA protein, as part of the Gag polyprotein precursor, facilitates protein–protein interactions that lead to the assembly of immature particles. Following protease activation and Gag polyprotein processing, CA also drives the assembly of the mature viral core. In the early stage of infection, the role of the CA protein is distinct. It controls the disassembly of the mature CA hexameric lattice i.e., uncoating, which is critical for the reverse transcription of the single-stranded RNA genome into double stranded DNA. These properties make CA a very attractive target for small molecule functioning as inhibitors of HIV-1 particle assembly and/or disassembly. Of these, inhibitors containing the PF74 scaffold have been extensively studied. In this study, we reported a series of modifications of the PF74 molecule and its characterization through a combination of biochemical and structural approaches. Our data supported the hypothesis that PF74 stabilizes the mature HIV-1 CA hexameric lattice. We identified derivatives with a higher in vitro stabilization activity in comparison to the original PF74 molecule.
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106
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Ohainle M, Kim K, Komurlu Keceli S, Felton A, Campbell E, Luban J, Emerman M. TRIM34 restricts HIV-1 and SIV capsids in a TRIM5α-dependent manner. PLoS Pathog 2020; 16:e1008507. [PMID: 32282853 PMCID: PMC7179944 DOI: 10.1371/journal.ppat.1008507] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Revised: 04/23/2020] [Accepted: 03/29/2020] [Indexed: 02/07/2023] Open
Abstract
The HIV-1 capsid protein makes up the core of the virion and plays a critical role in early steps of HIV replication. Due to its exposure in the cytoplasm after entry, HIV capsid is a target for host cell factors that act directly to block infection such as TRIM5α and MxB. Several host proteins also play a role in facilitating infection, including in the protection of HIV-1 capsid from recognition by host cell restriction factors. Through an unbiased screening approach, called HIV-CRISPR, we show that the CPSF6-binding deficient, N74D HIV-1 capsid mutant is sensitive to restriction mediated by human TRIM34, a close paralog of the well-characterized HIV restriction factor TRIM5α. This restriction occurs at the step of reverse transcription, is independent of interferon stimulation, and limits HIV-1 infection in key target cells of HIV infection including CD4+ T cells and monocyte-derived dendritic cells. TRIM34 can also restrict some SIV capsids. TRIM34 restriction requires TRIM5α as knockout or knockdown of TRIM5α results in a loss of antiviral activity. Through immunofluorescence studies, we show that TRIM34 and TRIM5α colocalize to cytoplasmic bodies and are more frequently observed to be associated with infecting N74D capsids than with WT HIV-1 capsids. Our results identify TRIM34 as an HIV-1 CA-targeting restriction factor and highlight the potential role for heteromultimeric TRIM interactions in contributing to restriction of HIV-1 infection in human cells.
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Affiliation(s)
- Molly Ohainle
- Divisions of Human Biology and Basic Sciences, Fred Hutch, Seattle, Washington, United States of America
| | - Kyusik Kim
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | - Sevnur Komurlu Keceli
- Department of Microbiology and Immunology, Stritch School of Medicine, Loyola University, Chicago, Maywood, Illinois, United States of America
| | - Abby Felton
- Divisions of Human Biology and Basic Sciences, Fred Hutch, Seattle, Washington, United States of America
| | - Ed Campbell
- Department of Microbiology and Immunology, Stritch School of Medicine, Loyola University, Chicago, Maywood, Illinois, United States of America
| | - Jeremy Luban
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | - Michael Emerman
- Divisions of Human Biology and Basic Sciences, Fred Hutch, Seattle, Washington, United States of America
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107
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Capsid-Labelled HIV To Investigate the Role of Capsid during Nuclear Import and Integration. J Virol 2020; 94:JVI.01024-19. [PMID: 31941774 DOI: 10.1128/jvi.01024-19] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Accepted: 11/24/2019] [Indexed: 12/22/2022] Open
Abstract
The HIV-1 capsid protein performs multiple roles in virus replication both during assembly and particle release and during virus trafficking into the nucleus. In order to decipher the roles of capsid protein during early replication, a reliable method to follow its intracellular distribution is required. To complement existing approaches to track HIV-1 capsid during early infection, we developed an HIV-1 imaging strategy, relying on viruses incorporating enhanced green fluorescent protein (eGFP)-tagged capsid (CA-eGFP) protein and mCherry-tagged integrase (IN-mCherry). Wild-type infectivity and sensitivity to inhibition by PF74 point to the functionality of CA-eGFP-containing complexes. Low numbers of CA-eGFP molecules were located inside the viral core and imported into the nucleus without significant loss in intensity. Less than 5% of particles carrying both CA-eGFP and IN-mCherry retained both labelled proteins after nuclear entry, implying a major uncoating event at the nuclear envelope dissociating IN and CA. Still, 20% of all CA-eGFP-containing complexes were detected in the nucleus. Unlike for IN-mCherry complexes, addition of the integrase inhibitor raltegravir had no effect on CA-eGFP-containing complexes, suggesting that these may be not (yet) competent for integration. Our imaging strategy offers alternative visualization of viral capsid trafficking and helps clarify its potential role during integration.IMPORTANCE HIV-1 capsid protein (CA) builds a conical shell protecting viral genomic RNA inside the virus particles. Upon entry into host cells, this shell disassembles in a process of uncoating, which is coordinated with reverse transcription of viral RNA into DNA. After uncoating, a portion of CA remains associated with the viral DNA and mediates its nuclear import and, potentially, integration into host DNA. In this study, we tagged CA with eGFP to follow its trafficking in host cells and address potential CA roles in the nucleus. We found that while functional viruses import the tagged CA into the nucleus, this capsid protein is not part of integration-competent complexes. The roles of nuclear CA thus remain to be established.
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108
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Chaudhuri E, Dash S, Balasubramaniam M, Padron A, Holland J, Sowd GA, Villalta F, Engelman AN, Pandhare J, Dash C. The HIV-1 capsid-binding host factor CPSF6 is post-transcriptionally regulated by the cellular microRNA miR-125b. J Biol Chem 2020; 295:5081-5094. [PMID: 32152226 DOI: 10.1074/jbc.ra119.010534] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Revised: 02/27/2020] [Indexed: 12/15/2022] Open
Abstract
Cleavage and polyadenylation specificity factor 6 (CPSF6) is a cellular protein involved in mRNA processing. Emerging evidence suggests that CPSF6 also plays key roles in HIV-1 infection, specifically during nuclear import and integration targeting. However, the cellular and molecular mechanisms that regulate CPSF6 expression are largely unknown. In this study, we report a post-transcriptional mechanism that regulates CPSF6 via the cellular microRNA miR-125b. An in silico analysis revealed that the 3'UTR of CPSF6 contains a miR-125b-binding site that is conserved across several mammalian species. Because miRNAs repress protein expression, we tested the effects of miR-125b expression on CPSF6 levels in miR-125b knockdown and over-expression experiments, revealing that miR-125b and CPSF6 levels are inversely correlated. To determine whether miR-125b post-transcriptionally regulates CPSF6, we introduced the 3'UTR of CPSF6 mRNA into a luciferase reporter and found that miR-125b negatively regulates CPSF6 3'UTR-driven luciferase activity. Accordingly, mutations in the miR-125b seed sequence abrogated the regulatory effect of the miRNA on the CPSF6 3'UTR. Finally, pulldown experiments demonstrated that miR-125b physically interacts with CPSF6 3'UTR. Interestingly, HIV-1 infection down-regulated miR-125b expression concurrent with up-regulation of CPSF6. Notably, miR-125b down-regulation in infected cells was not due to reduced pri-miRNA or pre-miRNA levels. However, miR-125b down-regulation depended on HIV-1 reverse transcription but not viral DNA integration. These findings establish a post-transcriptional mechanism that controls CPSF6 expression and highlight a novel function of miR-125b during HIV-host interaction.
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Affiliation(s)
- Evan Chaudhuri
- Center for AIDS Health Disparities Research, Meharry Medical College, Nashville, Tennessee 37208.,Department of Biochemistry, Cancer Biology, Pharmacology and Neuroscience, Meharry Medical College, Nashville, Tennessee 37208
| | - Sabyasachi Dash
- Center for AIDS Health Disparities Research, Meharry Medical College, Nashville, Tennessee 37208.,Department of Biochemistry, Cancer Biology, Pharmacology and Neuroscience, Meharry Medical College, Nashville, Tennessee 37208.,School of Biotechnology, KIIT University, Bhubaneswar, Odisha 751024, India.,Department of Pathology and Laboratory Medicine, Weill Cornell Medicine, New York, New York 10065
| | - Muthukumar Balasubramaniam
- Center for AIDS Health Disparities Research, Meharry Medical College, Nashville, Tennessee 37208.,Department of Biochemistry, Cancer Biology, Pharmacology and Neuroscience, Meharry Medical College, Nashville, Tennessee 37208
| | - Adrian Padron
- Department of Biochemistry, Cancer Biology, Pharmacology and Neuroscience, Meharry Medical College, Nashville, Tennessee 37208.,Department of Microbiology, Immunology, and Physiology, Meharry Medical College, Nashville, Tennessee 37208.,School of Graduate Studies and Research, Meharry Medical College, Nashville, Tennessee 37208
| | - Joseph Holland
- Center for AIDS Health Disparities Research, Meharry Medical College, Nashville, Tennessee 37208.,Department of Biochemistry, Cancer Biology, Pharmacology and Neuroscience, Meharry Medical College, Nashville, Tennessee 37208
| | - Gregory A Sowd
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, Massachusetts 02215.,Department of Medicine, Harvard Medical School, Boston, Massachusetts 02115
| | - Fernando Villalta
- Center for AIDS Health Disparities Research, Meharry Medical College, Nashville, Tennessee 37208.,Department of Microbiology, Immunology, and Physiology, Meharry Medical College, Nashville, Tennessee 37208
| | - 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
| | - Jui Pandhare
- Center for AIDS Health Disparities Research, Meharry Medical College, Nashville, Tennessee 37208.,Department of Microbiology, Immunology, and Physiology, Meharry Medical College, Nashville, Tennessee 37208.,School of Graduate Studies and Research, Meharry Medical College, Nashville, Tennessee 37208
| | - Chandravanu Dash
- Center for AIDS Health Disparities Research, Meharry Medical College, Nashville, Tennessee 37208 .,Department of Biochemistry, Cancer Biology, Pharmacology and Neuroscience, Meharry Medical College, Nashville, Tennessee 37208.,School of Graduate Studies and Research, Meharry Medical College, Nashville, Tennessee 37208
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109
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Ingram Z, Taylor M, Okland G, Martin R, Hulme AE. Characterization of HIV-1 uncoating in human microglial cell lines. Virol J 2020; 17:31. [PMID: 32143686 PMCID: PMC7060623 DOI: 10.1186/s12985-020-01301-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Accepted: 02/21/2020] [Indexed: 12/17/2022] Open
Abstract
Background After viral fusion with the cell membrane, the conical capsid of HIV-1 disassembles by a process called uncoating. Previously we have utilized the CsA washout assay, in which TRIM-CypA mediated restriction of viral replication is used to detect the state of the viral capsid, to study the kinetics of HIV-1 uncoating in owl monkey kidney (OMK) and HeLa cells. Here we have extended this analysis to the human microglial cell lines CHME3 and C20 to characterize uncoating in a cell type that is a natural target of HIV infection. Methods The CsA washout was used to characterize uncoating of wildtype and capsid mutant viruses in CHME3 and C20 cells. Viral fusion assays and nevirapine addition assays were performed to relate the kinetics of viral fusion and reverse transcription to uncoating. Results We found that uncoating initiated within the first hour after viral fusion and was facilitated by reverse transcription in CHME3 and C20 cells. The capsid mutation A92E did not significantly alter uncoating kinetics. Viruses with capsid mutations N74D and E45A decreased the rate of uncoating in CHME3 cells, but did not alter reverse transcription. Interestingly, the second site suppressor capsid mutation R132T was able to rescue the uncoating kinetics of the E45A mutation, despite having a hyperstable capsid. Conclusions These results are most similar to previously observed characteristics of uncoating in HeLa cells and support the model in which uncoating is initiated by early steps of reverse transcription in the cytoplasm. A comparison of the uncoating kinetics of CA mutant viruses in OMK and CHME3 cells reveals the importance of cellular factors in the process of uncoating. The E45A/R132T mutant virus specifically suggests that disrupted interactions with cellular factors, rather than capsid stability, is responsible for the delayed uncoating kinetics seen in E45A mutant virus. Future studies aimed at identifying these factors will be important for understanding the process of uncoating and the development of interventions to disrupt this process.
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Affiliation(s)
- Zachary Ingram
- Department of Biomedical Sciences, Missouri State University, Springfield, MO, USA
| | - Melanie Taylor
- Department of Biomedical Sciences, Missouri State University, Springfield, MO, USA
| | - Glister Okland
- Department of Biomedical Sciences, Missouri State University, Springfield, MO, USA
| | - Richard Martin
- Department of Biomedical Sciences, Missouri State University, Springfield, MO, USA
| | - Amy E Hulme
- Department of Biomedical Sciences, Missouri State University, Springfield, MO, USA.
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110
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Abstract
For several decades, retroviral core uncoating has been thought to occur in the cytoplasm in coordination with reverse transcription, and while some recent studies have concluded that HIV-1 uncoating occurs at the nuclear envelope during nuclear import, none have concluded that uncoating occurs in the nucleus. Here, we developed methods to study HIV-1 uncoating by direct labeling and quantification of the viral capsid protein associated with infectious viral cores that produced transcriptionally active proviruses. We find that infectious viral cores in the nuclei of infected cells are largely intact and uncoat near their integration sites just before integration. These unexpected findings fundamentally change our understanding of HIV-1 postentry replication events. HIV-1 capsid core disassembly (uncoating) must occur before integration of viral genomic DNA into the host chromosomes, yet remarkably, the timing and cellular location of uncoating is unknown. Previous studies have proposed that intact viral cores are too large to fit through nuclear pores and uncoating occurs in the cytoplasm in coordination with reverse transcription or at the nuclear envelope during nuclear import. The capsid protein (CA) content of the infectious viral cores is not well defined because methods for directly labeling and quantifying the CA in viral cores have been unavailable. In addition, it has been difficult to identify the infectious virions because only one of ∼50 virions in infected cells leads to productive infection. Here, we developed methods to analyze HIV-1 uncoating by direct labeling of CA with GFP and to identify infectious virions by tracking viral cores in living infected cells through viral DNA integration and proviral DNA transcription. Astonishingly, our results show that intact (or nearly intact) viral cores enter the nucleus through a mechanism involving interactions with host protein cleavage and polyadenylation specificity factor 6 (CPSF6), complete reverse transcription in the nucleus before uncoating, and uncoat <1.5 h before integration near (<1.5 μm) their genomic integration sites. These results fundamentally change our current understanding of HIV-1 postentry replication events including mechanisms of nuclear import, uncoating, reverse transcription, integration, and evasion of innate immunity.
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111
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A Quantitative Genetic Interaction Map of HIV Infection. Mol Cell 2020; 78:197-209.e7. [PMID: 32084337 DOI: 10.1016/j.molcel.2020.02.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Revised: 01/10/2020] [Accepted: 02/02/2020] [Indexed: 12/16/2022]
Abstract
We have developed a platform for quantitative genetic interaction mapping using viral infectivity as a functional readout and constructed a viral host-dependency epistasis map (vE-MAP) of 356 human genes linked to HIV function, comprising >63,000 pairwise genetic perturbations. The vE-MAP provides an expansive view of the genetic dependencies underlying HIV infection and can be used to identify drug targets and study viral mutations. We found that the RNA deadenylase complex, CNOT, is a central player in the vE-MAP and show that knockout of CNOT1, 10, and 11 suppressed HIV infection in primary T cells by upregulating innate immunity pathways. This phenotype was rescued by deletion of IRF7, a transcription factor regulating interferon-stimulated genes, revealing a previously unrecognized host signaling pathway involved in HIV infection. The vE-MAP represents a generic platform that can be used to study the global effects of how different pathogens hijack and rewire the host during infection.
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112
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Cellular Cleavage and Polyadenylation Specificity Factor 6 (CPSF6) Mediates Nuclear Import of Human Bocavirus 1 NP1 Protein and Modulates Viral Capsid Protein Expression. J Virol 2020; 94:JVI.01444-19. [PMID: 31666379 DOI: 10.1128/jvi.01444-19] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2019] [Accepted: 10/18/2019] [Indexed: 12/13/2022] Open
Abstract
Human bocavirus 1 (HBoV1), which belongs to the genus Bocaparvovirus of the Parvoviridae family, causes acute respiratory tract infections in young children. In vitro, HBoV1 infects polarized primary human airway epithelium (HAE) cultured at an air-liquid interface (HAE-ALI). HBoV1 encodes a small nonstructural protein, nuclear protein 1 (NP1), that plays an essential role in the maturation of capsid protein (VP)-encoding mRNAs and viral DNA replication. In this study, we determined the broad interactome of NP1 using the proximity-dependent biotin identification (BioID) assay combined with mass spectrometry (MS). We confirmed that two host mRNA processing factors, DEAH-box helicase 15 (DHX15) and cleavage and polyadenylation specificity factor 6 (CPSF6; also known as CFIm68), a subunit of the cleavage factor Im complex (CFIm), interact with HBoV1 NP1 independently of any DNA or mRNAs. Knockdown of CPSF6 significantly decreased the expression of capsid protein but not that of DHX15. We further demonstrated that NP1 directly interacts with CPSF6 in vitro and colocalizes within the virus replication centers. Importantly, we revealed a novel role of CPSF6 in the nuclear import of NP1, in addition to the critical role of CPSF6 in NP1-facilitated maturation of VP-encoding mRNAs. Thus, our study suggests that CPSF6 interacts with NP1 to escort NP1 imported into the nucleus for its function in the modulation of viral mRNA processing and viral DNA replication.IMPORTANCE Human bocavirus 1 (HBoV1) is one of the significant pathogens causing acute respiratory tract infections in young children worldwide. HBoV1 encodes a small nonstructural protein (NP1) that plays an important role in the maturation of viral mRNAs encoding capsid proteins as well as in viral DNA replication. Here, we identified a critical host factor, CPSF6, that directly interacts with NP1, mediates the nuclear import of NP1, and plays a role in the maturation of capsid protein-encoding mRNAs in the nucleus. The identification of the direct interaction between viral NP1 and host CPSF6 provides new insights into the mechanism by which a viral small nonstructural protein facilitates the multiple regulation of viral gene expression and replication and reveals a novel target for potent antiviral drug development.
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113
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Abstract
From cellular deposition of the HIV-1 capsid to integration of the viral genome, the capsid constitutes a primary target of a variety of host proteins that work to either promote or inhibit HIV-1 infection. Successful progression of HIV-1 infection depends on interactions between the capsid and host factors involved in stability, cellular transport, nuclear import, and genome integration. The virus must also guard its reverse-transcribing genome inside the capsid from host restriction factors that bind the capsid and suppress infection. Understanding the structure and dynamics of the capsid protein (CA) component and the assembled capsid sheds light on the molecular underpinnings of overall capsid stability, architecture, and flexibility that govern HIV-1 capsid–host interactions. The vast majority of these interactions are mediated through recognition of higher order interfaces only present in the assembled capsid lattice. Patterns formed at these interfaces serve as signposts for capsid-binders. Here we provide a graphical summary of the intricate interactions between host factors and the HIV-1 capsid while highlighting recent research. Insights into how host proteins interact with the capsid is crucial for understanding the HIV-1 replication cycle and developing antiviral therapeutics to prevent viral genome integration.
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114
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Acton O, Grant T, Nicastro G, Ball NJ, Goldstone DC, Robertson LE, Sader K, Nans A, Ramos A, Stoye JP, Taylor IA, Rosenthal PB. Structural basis for Fullerene geometry in a human endogenous retrovirus capsid. Nat Commun 2019; 10:5822. [PMID: 31862888 PMCID: PMC6925226 DOI: 10.1038/s41467-019-13786-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Accepted: 11/28/2019] [Indexed: 01/09/2023] Open
Abstract
The HML2 (HERV-K) group constitutes the most recently acquired family of human endogenous retroviruses, with many proviruses less than one million years old. Many maintain intact open reading frames and provirus expression together with HML2 particle formation are observed in early stage human embryo development and are associated with pluripotency as well as inflammatory disease, cancers and HIV-1 infection. Here, we reconstruct the core structural protein (CA) of an HML2 retrovirus, assemble particles in vitro and employ single particle cryogenic electron microscopy (cryo-EM) to determine structures of four classes of CA Fullerene shell assemblies. These icosahedral and capsular assemblies reveal at high-resolution the molecular interactions that allow CA to form both pentamers and hexamers and show how invariant pentamers and structurally plastic hexamers associate to form the unique polyhedral structures found in retroviral cores.
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Affiliation(s)
- Oliver Acton
- Structural Biology of Cells and Viruses Laboratory, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
- Department of Biochemistry, University of Washington, Seattle, WA, USA
| | - Tim Grant
- Structural Biology of Cells and Viruses Laboratory, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
- Howard Hughes Medical Institute, Janelia Research Campus, Ashburn, VA, 20147, USA
| | - Giuseppe Nicastro
- Macromolecular Structure Laboratory, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
| | - Neil J Ball
- Macromolecular Structure Laboratory, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
| | - David C Goldstone
- Macromolecular Structure Laboratory, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
- School of Biological Sciences, University of Auckland, Auckland, New Zealand
| | - Laura E Robertson
- Macromolecular Structure Laboratory, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
| | - Kasim Sader
- Structural Biology of Cells and Viruses Laboratory, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
- Thermo Fisher Scientific Materials and Structural Analysis, Eindhoven, Netherlands
| | - Andrea Nans
- Structural Biology of Cells and Viruses Laboratory, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
| | - Andres Ramos
- Division of Molecular Structure, MRC National Institute for Medical Research, London, NW7 1AA, UK
- Institute of Structural and Molecular Biology, University College London, London, UK
| | - Jonathan P Stoye
- Retrovirus-Host Interactions Laboratory, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
- Department of Medicine, Imperial College London, London, SW7 2AZ, UK
| | - Ian A Taylor
- Macromolecular Structure Laboratory, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK.
| | - Peter B Rosenthal
- Structural Biology of Cells and Viruses Laboratory, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK.
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115
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Mallery DL, Faysal KMR, Kleinpeter A, Wilson MSC, Vaysburd M, Fletcher AJ, Novikova M, Böcking T, Freed EO, Saiardi A, James LC. Cellular IP 6 Levels Limit HIV Production while Viruses that Cannot Efficiently Package IP 6 Are Attenuated for Infection and Replication. Cell Rep 2019; 29:3983-3996.e4. [PMID: 31851928 PMCID: PMC6931105 DOI: 10.1016/j.celrep.2019.11.050] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Revised: 10/11/2019] [Accepted: 11/12/2019] [Indexed: 12/23/2022] Open
Abstract
HIV-1 hijacks host proteins to promote infection. Here we show that HIV is also dependent upon the host metabolite inositol hexakisphosphate (IP6) for viral production and primary cell replication. HIV-1 recruits IP6 into virions using two lysine rings in its immature hexamers. Mutation of either ring inhibits IP6 packaging and reduces viral production. Loss of IP6 also results in virions with highly unstable capsids, leading to a profound loss of reverse transcription and cell infection. Replacement of one ring with a hydrophobic isoleucine core restores viral production, but IP6 incorporation and infection remain impaired, consistent with an independent role for IP6 in stable capsid assembly. Genetic knockout of biosynthetic kinases IPMK and IPPK reveals that cellular IP6 availability limits the production of diverse lentiviruses, but in the absence of IP6, HIV-1 packages IP5 without loss of infectivity. Together, these data suggest that IP6 is a critical cofactor for HIV-1 replication.
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Affiliation(s)
- Donna L Mallery
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK
| | - K M Rifat Faysal
- EMBL Australia Node in Single Molecule Science and ARC Centre of Excellence in Advanced Molecular Imaging, School of Medical Sciences, UNSW Sydney, Sydney NSW, Australia
| | - Alex Kleinpeter
- Virus-Cell Interaction Section, HIV Dynamics and Replication Program, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702-1201, USA
| | - Miranda S C Wilson
- MRC Laboratory for Molecular Cell Biology, University College London, London, UK
| | - Marina Vaysburd
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK
| | - Adam J Fletcher
- MRC Protein Phosphorylation and Ubiquitylation Unit, University of Dundee, Dundee, UK
| | - Mariia Novikova
- Virus-Cell Interaction Section, HIV Dynamics and Replication Program, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702-1201, USA
| | - Till Böcking
- EMBL Australia Node in Single Molecule Science and ARC Centre of Excellence in Advanced Molecular Imaging, School of Medical Sciences, UNSW Sydney, Sydney NSW, Australia
| | - Eric O Freed
- Virus-Cell Interaction Section, HIV Dynamics and Replication Program, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702-1201, USA
| | - Adolfo Saiardi
- MRC Laboratory for Molecular Cell Biology, University College London, London, UK
| | - Leo C James
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK.
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116
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Fu X, Ning J, Zhong Z, Ambrose Z, Charles Watkins S, Zhang P. AutoCLEM: An Automated Workflow for Correlative Live-Cell Fluorescence Microscopy and Cryo-Electron Tomography. Sci Rep 2019; 9:19207. [PMID: 31844138 PMCID: PMC6915765 DOI: 10.1038/s41598-019-55766-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Accepted: 12/02/2019] [Indexed: 01/06/2023] Open
Abstract
Correlative light and electron microscopy (CLEM) combines the strengths of both light and electron imaging modalities and enables linking of biological spatiotemporal information from live-cell fluorescence light microscopy (fLM) to high-resolution cellular ultra-structures from cryo-electron microscopy and tomography (cryoEM/ET). This has been previously achieved by using fLM signals to localize the regions of interest under cryogenic conditions. The correlation process, however, is often tedious and time-consuming with low throughput and limited accuracy, because multiple correlation steps at different length scales are largely carried out manually. Here, we present an experimental workflow, AutoCLEM, which overcomes the existing limitations and improves the performance and throughput of CLEM methods, and associated software. The AutoCLEM system encompasses a high-speed confocal live-cell imaging module to acquire an automated fLM grid atlas that is linked to the cryoEM grid atlas, followed by cryofLM imaging after freezing. The fLM coordinates of the targeted areas are automatically converted to cryoEM/ET and refined using fluorescent fiducial beads. This AutoCLEM workflow significantly accelerates the correlation efficiency between live-cell fluorescence imaging and cryoEM/ET structural analysis, as demonstrated by visualizing human immunodeficiency virus type 1 (HIV-1) interacting with host cells.
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Affiliation(s)
- Xiaofeng Fu
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15260, USA
| | - Jiying Ning
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15260, USA
| | - Zhou Zhong
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15260, USA
| | - Zandrea Ambrose
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15260, USA
| | - Simon Charles Watkins
- Department of Cell Biology and Physiology, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15260, USA
| | - Peijun Zhang
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15260, USA. .,Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, OX3 7BN, UK. .,Electron Bio-Imaging Centre, Diamond Light Sources, Harwell Science and Innovation Campus, Didcot, OX11 0DE, UK.
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117
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Dostálková A, Hadravová R, Kaufman F, Křížová I, Škach K, Flegel M, Hrabal R, Ruml T, Rumlová M. A simple, high-throughput stabilization assay to test HIV-1 uncoating inhibitors. Sci Rep 2019; 9:17076. [PMID: 31745222 PMCID: PMC6863892 DOI: 10.1038/s41598-019-53483-w] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Accepted: 10/30/2019] [Indexed: 02/04/2023] Open
Abstract
Shortly after entering the cell, HIV-1 copies its genomic RNA into double-stranded DNA in a process known as reverse transcription. This process starts inside a core consisting of an enclosed lattice of capsid proteins that protect the viral RNA from cytosolic sensors and degradation pathways. To accomplish reverse transcription and integrate cDNA into the host cell genome, the capsid shell needs to be disassembled, or uncoated. Premature or delayed uncoating attenuates reverse transcription and blocks HIV-1 infectivity. Small molecules that bind to the capsid lattice of the HIV-1 core and either destabilize or stabilize its structure could thus function as effective HIV-1 inhibitors. To screen for such compounds, we modified our recently developed FAITH assay to allow direct assessment of the stability of in vitro preassembled HIV-1 capsid-nucleocapsid (CANC) tubular particles. This new assay is a high-throughput fluorescence method based on measuring the amount of nucleic acid released from CANC complexes under disassembly conditions. The amount of disassembled CANC particles and released nucleic acid is proportional to the fluorescence signal, from which the relative percentage of CANC stability can be calculated. We consider our assay a potentially powerful tool for in vitro screening for compounds that alter HIV disassembly.
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Affiliation(s)
- Alžběta Dostálková
- Department of Biotechnology, University of Chemistry and Technology, Prague, 166 28, Czech Republic
| | - Romana Hadravová
- Department of Biotechnology, University of Chemistry and Technology, Prague, 166 28, Czech Republic
- Institute of Organic Chemistry and Biochemistry IOCB Research Centre & Gilead Sciences, Academy of Sciences of the Czech Republic, Flemingovo nám. 2, 166 10, Prague, Czech Republic
| | - Filip Kaufman
- Department of Biotechnology, University of Chemistry and Technology, Prague, 166 28, Czech Republic
| | - Ivana Křížová
- Department of Biotechnology, University of Chemistry and Technology, Prague, 166 28, Czech Republic
| | - Kryštof Škach
- Department of Chemistry of Natural Compounds University of Chemistry and Technology, Prague, 166 28, Prague, Czech Republic
| | - Martin Flegel
- Department of Chemistry of Natural Compounds University of Chemistry and Technology, Prague, 166 28, Prague, Czech Republic
| | - Richard Hrabal
- NMR Laboratory, University of Chemistry and Technology, Prague, 166 28, Prague, Czech Republic
| | - Tomáš Ruml
- Department of Biochemistry and Microbiology, University of Chemistry and Technology, Prague, 166 28, Prague, Czech Republic
| | - Michaela Rumlová
- Department of Biotechnology, University of Chemistry and Technology, Prague, 166 28, Czech Republic.
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118
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Multiple Pathways To Avoid Beta Interferon Sensitivity of HIV-1 by Mutations in Capsid. J Virol 2019; 93:JVI.00986-19. [PMID: 31511380 PMCID: PMC6854511 DOI: 10.1128/jvi.00986-19] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Accepted: 08/28/2019] [Indexed: 12/11/2022] Open
Abstract
HIV-1 infection causes robust innate immune activation in virus-infected patients. This immune activation is characterized by elevated levels of type I interferons (IFNs), which can block HIV-1 replication. Recent studies suggest that the viral capsid protein (CA) is a determinant for the sensitivity of HIV-1 to IFN-mediated restriction. Specifically, it was reported that the loss of CA interactions with CPSF6 or CypA leads to higher IFN sensitivity. However, the molecular mechanism of CA adaptation to IFN sensitivity is largely unknown. Here, we experimentally evolved an IFN-β-hypersensitive CA mutant which showed decreased binding to CPSF6 and CypA in IFN-β-treated cells. The CA mutations that emerged from this adaptation indeed conferred IFN-β resistance. Our genetic assays suggest a limited contribution of known host factors to IFN-β resistance. Strikingly, one of these mutations accelerated the kinetics of reverse transcription and uncoating. Our findings suggest that HIV-1 selected multiple, known host factor-independent pathways to avoid IFN-β-mediated restriction. Type I interferons (IFNs), including alpha IFN (IFN-α) and IFN-β, potently suppress HIV-1 replication by upregulating IFN-stimulated genes (ISGs). The viral capsid protein (CA) partly determines the sensitivity of HIV-1 to IFNs. However, it remains to be determined whether CA-related functions, including utilization of known host factors, reverse transcription, and uncoating, affect the sensitivity of HIV-1 to IFN-mediated restriction. Recently, we identified an HIV-1 CA variant that is unusually sensitive to IFNs. This variant, called the RGDA/Q112D virus, contains multiple mutations in CA: H87R, A88G, P90D, P93A, and Q112D. To investigate how an IFN-hypersensitive virus can evolve to overcome IFN-β-mediated blocks targeting the viral capsid, we adapted the RGDA/Q112D virus in IFN-β-treated cells. We successfully isolated IFN-β-resistant viruses which contained either a single Q4R substitution or the double amino acid change G94D/G116R. These two IFN-β resistance mutations variably changed the sensitivity of CA binding to human myxovirus resistance B (MxB), cleavage and polyadenylation specificity factor 6 (CPSF6), and cyclophilin A (CypA), indicating that the observed loss of sensitivity was not due to interactions with these known host CA-interacting factors. In contrast, the two mutations apparently functioned through distinct mechanisms. The Q4R mutation dramatically accelerated the kinetics of reverse transcription and initiation of uncoating of the RGDA/Q112D virus in the presence or absence of IFN-β, whereas the G94D/G116R mutations affected reverse transcription only in the presence of IFN-β, most consistent with a mechanism of the disruption of binding to an unknown IFN-β-regulated host factor. These results suggest that HIV-1 can exploit multiple, known host factor-independent pathways to avoid IFN-β-mediated restriction by altering capsid sequences and subsequent biological properties. IMPORTANCE HIV-1 infection causes robust innate immune activation in virus-infected patients. This immune activation is characterized by elevated levels of type I interferons (IFNs), which can block HIV-1 replication. Recent studies suggest that the viral capsid protein (CA) is a determinant for the sensitivity of HIV-1 to IFN-mediated restriction. Specifically, it was reported that the loss of CA interactions with CPSF6 or CypA leads to higher IFN sensitivity. However, the molecular mechanism of CA adaptation to IFN sensitivity is largely unknown. Here, we experimentally evolved an IFN-β-hypersensitive CA mutant which showed decreased binding to CPSF6 and CypA in IFN-β-treated cells. The CA mutations that emerged from this adaptation indeed conferred IFN-β resistance. Our genetic assays suggest a limited contribution of known host factors to IFN-β resistance. Strikingly, one of these mutations accelerated the kinetics of reverse transcription and uncoating. Our findings suggest that HIV-1 selected multiple, known host factor-independent pathways to avoid IFN-β-mediated restriction.
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119
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Abstract
The HIV-1 capsid performs essential functions during early viral replication and is an interesting target for novel antivirals. Thus, understanding molecular and structural details of capsid function will be important for elucidating early HIV-1 (and retroviral in general) replication in relevant target cells and may also aid antiviral development. Here, we show that HIV-1 capsids stay largely intact during transport to the nucleus of infected T cells but appear to uncoat upon entry into the nucleoplasm. These results support the hypothesis that capsids protect the HIV-1 genome from cytoplasmic defense mechanisms and target the genome toward the nucleus. A protective role of the capsid could be a paradigm that also applies to other viruses. Our findings raise the question of how reverse transcription of the HIV-1 genome is accomplished in the context of the capsid structure and whether the process is completed before the capsid is uncoated at the nuclear pore. HIV-1 infects host cells by fusion at the plasma membrane, leading to cytoplasmic entry of the viral capsid encasing the genome and replication machinery. The capsid eventually needs to disassemble, but time and location of uncoating are not fully characterized and may vary depending on the host cell. To study the fate of the capsid by fluorescence and superresolution (STED) microscopy, we established an experimental system that allows discrimination of subviral structures in the cytosol from intact virions at the plasma membrane or in endosomes without genetic modification of the virus. Quantitative microscopy of infected SupT1-R5 cells revealed that the CA signal on cytosolic HIV-1 complexes corresponded to ∼50% of that found in virions at the cell surface, in agreement with dissociation of nonassembled CA molecules from entering capsids after membrane fusion. The relative amount of CA in postfusion complexes remained stable until they reached the nuclear pore complex, while subviral structures in the nucleus of infected cells lacked detectable CA. An HIV-1 variant defective in binding of the host protein cleavage and polyadenylation specificity factor 6 (CPSF6) exhibited accumulation of CA-positive subviral complexes close to the nuclear envelope without loss of infectivity; STED microscopy revealed direct association of these complexes with nuclear pores. These results support previous observations indicating capsid uncoating at the nuclear pore in infected T-cell lines. They suggest that largely intact HIV-1 capsids dock at the nuclear pore in infected SupT1-R5 cells, with CPSF6 being a facilitator of nucleoplasmic entry in this cell type, as has been observed for infected macrophages.
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120
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Anderson-Daniels J, Singh PK, Sowd GA, Li W, Engelman AN, Aiken C. Dominant Negative MA-CA Fusion Protein Is Incorporated into HIV-1 Cores and Inhibits Nuclear Entry of Viral Preintegration Complexes. J Virol 2019; 93:e01118-19. [PMID: 31413124 PMCID: PMC6803256 DOI: 10.1128/jvi.01118-19] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2019] [Accepted: 08/03/2019] [Indexed: 11/20/2022] Open
Abstract
Particle maturation is a critical step in the HIV-1 replication cycle that requires proteolytic cleavage of the Gag polyprotein into its constitutive proteins: the matrix (MA), capsid (CA), nucleocapsid (NC), and p6 proteins. The accurate and efficient cleavage of Gag is essential for virion infectivity; inhibitors of the viral protease are potent antivirals, and substitutions in Gag that prevent its cleavage result in reduced HIV-1 infectivity. In a previous study, a mutation inhibiting cleavage at the MA-CA junction was observed to potently inhibit virus infection: incorporation of small amounts of uncleaved MA-CA protein into HIV-1 particles inhibited infectivity by ∼95%, and the resulting viral particles exhibited aberrant capsids. Here we report a detailed mechanistic analysis of HIV-1 particles bearing uncleaved MA-CA protein. We show that the particles contain stable cores and can efficiently saturate host restriction by TRIMCyp in target cells. We further show that MA-CA associates with CA in particles without detectably affecting the formation of intermolecular CA interfaces. Incorporation of MA-CA did not markedly affect reverse transcription in infected cells, but nuclear entry was impaired and integration targeting was altered. Additionally, results from mutational analysis of Gag revealed that membrane-binding elements of MA contribute to the antiviral activity of uncleaved MA-CA protein. Our results suggest that small amounts of partially processed Gag subunits coassemble with CA during virion maturation, resulting in impaired capsid functions.IMPORTANCE To become infectious, newly formed HIV-1 particles undergo a process of maturation in which the viral polyproteins are cleaved into smaller components. A previous study demonstrated that inclusion of even small quantities of an uncleavable mutant Gag polyprotein results in a strong reduction in virus infectivity. Here we show that the mechanism of transdominant inhibition by uncleavable Gag involves inhibition of nuclear entry and alteration of viral integration sites. Additionally, the results of mutational analysis suggest that the membrane-binding activity of Gag is a major requirement for the antiviral activity. These results further define the antiviral mechanism of uncleavable Gag, which may be useful for exploiting this effect to develop new antivirals.
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Affiliation(s)
- Jordan Anderson-Daniels
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Parmit K Singh
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
- Department of Medicine, Harvard Medical School, Boston, Massachusetts, USA
| | - Gregory A Sowd
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
- Department of Medicine, Harvard Medical School, Boston, Massachusetts, USA
| | - Wen Li
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
- Department of Medicine, Harvard Medical School, Boston, Massachusetts, USA
| | - Alan N Engelman
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
- Department of Medicine, Harvard Medical School, Boston, Massachusetts, USA
| | - Christopher Aiken
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
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121
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McArthur C, Gallazzi F, Quinn TP, Singh K. HIV Capsid Inhibitors Beyond PF74. Diseases 2019; 7:diseases7040056. [PMID: 31671622 PMCID: PMC6956309 DOI: 10.3390/diseases7040056] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Revised: 10/21/2019] [Accepted: 10/27/2019] [Indexed: 01/13/2023] Open
Abstract
Human immunodeficiency virus (HIV) capsid plays important roles at multiple stages of viral replication. At the initial stages, controlled uncoating (disassembly) of the capsid ensures efficient reverse transcription of the single-stranded RNA genome, into the double-stranded DNA. Whereas at later stages, a proper assembly of capsid ensures the formation of a mature infectious virus particle. Hence, the inhibition of capsid assembly and/or disassembly has been recognized as a potential therapeutic strategy, and several capsid inhibitors have been reported. Of these, PF-3450074 (PF74) has been extensively studied. Recently reported GS-CA inhibitors (GS-CA1 and GS-6207), have shown a strong potential and appear to contain a PF74 scaffold. The location of resistance mutations and the results of structural studies further suggest that GS-CA compounds and PF74 share the same binding pocket, which is located between capsid monomers. Additionally, phenylalanine derivatives containing the PF74 scaffold show slightly enhanced capsid inhibiting activity. A comparison of capsid structures in complex with host factors and PF74, reveals the presence of common chemical entities at topologically equivalent positions. Here we present the status of capsid inhibitors that contain PF74 scaffolds and propose that the PF74 scaffold may be used to develop strong and safe capsid inhibitors.
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Affiliation(s)
- Carole McArthur
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri, Kansas, MO 64108, USA.
- Kansas City School of Medicine, University of Missouri, Kansas, MO 64108, USA.
- Department of Pathology, Truman Medical Center, Kansas, MO, 64108, USA.
| | - Fabio Gallazzi
- Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA.
- Department of Chemistry, University of Missouri, Columbia, MO 65211, USA.
| | - Thomas P Quinn
- Department of Biochemistry, University of Missouri, Columbia, MO 65211, USA.
| | - Kamal Singh
- Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA.
- Department of Molecular Microbiology and Immunology, University of Missouri, Columbia, MO 65211, USA.
- Division of Clinical Microbiology, Department of Laboratory Medicine, Karolinska Institute, 14186 Stockholm, Sweden.
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122
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Interferon-Inducible MicroRNA miR-128 Modulates HIV-1 Replication by Targeting TNPO3 mRNA. J Virol 2019; 93:JVI.00364-19. [PMID: 31341054 DOI: 10.1128/jvi.00364-19] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Accepted: 07/12/2019] [Indexed: 12/18/2022] Open
Abstract
The HIV/AIDS pandemic remains an important threat to human health. We have recently demonstrated that a novel microRNA (miR), miR-128, represses retrotransposon long interspaced element 1 (L1) by a dual mechanism, namely, by directly targeting the coding region of the L1 RNA and by repressing a required nuclear import factor (TNPO1). We have further determined that miR-128 represses the expression of all three TNPO proteins (transportins TNPO1, TNPO2, and TNPO3). Here, we establish that miR-128 also influences HIV-1 replication by repressing TNPO3, a factor that regulates HIV-1 nuclear import and viral; replication of TNPO3 is well established to regulate HIV-1 nuclear import and viral replication. Here, we report that type I interferon (IFN)-inducible miR-128 directly targets two sites in the TNPO3 mRNA, significantly downregulating TNPO3 mRNA and protein expression levels. Challenging miR-modulated Jurkat cells or primary CD4+ T-cells with wild-type (WT), replication-competent HIV-1 demonstrated that miR-128 reduces viral replication and delays spreading of infection. Manipulation of miR-128 levels in HIV-1 target cell lines and in primary CD4+ T-cells by overexpression or knockdown showed that reduction of TNPO3 levels by miR-128 significantly affects HIV-1 replication but not murine leukemia virus (MLV) infection and that miR-128 modulation of HIV-1 replication is reduced with TNPO3-independent HIV-1 virus, suggesting that miR-128-indued TNPO3 repression contributes to the inhibition of HIV-1 replication. Finally, we determine that anti-miR-128 partly neutralizes the IFN-mediated block of HIV-1. Thus, we have established a novel role of miR-128 in antiviral defense in human cells, namely inhibiting HIV-1 replication by altering the cellular milieu through targeting factors that include TNPO3.IMPORTANCE HIV-1 is the causative agent of AIDS. During HIV-1 infection, type I interferons (IFNs) are induced, and their effectors limit HIV-1 replication at multiple steps in its life cycle. However, the cellular targets of INFs are still largely unknown. In this study, we identified the interferon-inducible microRNA (miR) miR-128, a novel antiviral mediator that suppresses the expression of the host gene TNPO3, which is known to modulate HIV-1 replication. Notably, we observe that anti-miR-128 partly neutralizes the IFN-mediated block of HIV-1. Elucidation of the mechanisms through which miR-128 impairs HIV-1 replication may provide novel candidates for the development of therapeutic interventions.
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The HIV-1 Capsid: More than Just a Delivery Package. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1215:69-83. [PMID: 31317496 DOI: 10.1007/978-3-030-14741-9_4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Productive HIV infection requires integration of viral genes into the host genome. But how viral DNA gets to the nucleus in the first place remains one of the most controversial yet deceptively simple questions in HIV post-entry biology. This is illustrated in cartoons of viral entry, which often depict the entry process as an 'explosion' of the HIV capsid in the cytosol and independent movement of viral DNA through nuclear pores and into the nucleus. HIV enters the cell cytosol with two encapsidated RNA strands and must undergo reverse transcription (RT) to synthesise DNA. Even here there is no consensus for where, when or how RT happens. HIV must get into the nucleus, which in a non-dividing cell requires transport through the nuclear pore. Finally, the virus must 'uncoat': shed its protein capsid to allow its DNA to be spliced with that of the host. Where the virus uncoats and whether this is a single or multi-step process are similarly hotly debated. Understanding these processes is further complicated by three broad factors. First, that there are inter-relationships between these processes that may ensure HIV undergoes the right step at the right place at the right time. Second, the host has cofactors which the virus is dependent upon and must recruit but also immune factors that can sense and inhibit virus and so must be avoided. Third, HIV post-entry biology is cell-type dependent-meaning that factors which are essential in one cell type can be redundant in another.
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The Conserved Tyr176/Leu177 Motif in the α-Helix 9 of the Feline Immunodeficiency Virus Capsid Protein Is Critical for Gag Particle Assembly. Viruses 2019; 11:v11090816. [PMID: 31487820 PMCID: PMC6783973 DOI: 10.3390/v11090816] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Revised: 08/31/2019] [Accepted: 09/02/2019] [Indexed: 01/19/2023] Open
Abstract
The capsid domain (CA) of the lentiviral Gag polyproteins has two distinct roles during virion morphogenesis. As a domain of Gag, it mediates the Gag–Gag interactions that drive immature particle assembly, whereas as a mature protein, it self-assembles into the conical core of the mature virion. Lentiviral CA proteins are composed of an N-terminal region with seven α-helices and a C-terminal domain (CA-CTD) formed by four α-helices. Structural studies performed in HIV-1 indicate that the CA-CTD helix 9 establishes homodimeric interactions that contribute to the formation of the hexameric Gag lattice in immature virions. Interestingly, the mature CA core also shows inter-hexameric associations involving helix 9 residues W184 and M185. The CA proteins of feline immunodeficiency virus (FIV) and equine infectious anemia virus (EIAV) exhibit, at equivalent positions in helix 9, the motifs Y176/L177 and L169/F170, respectively. In this paper, we investigated the relevance of the Y176/L177 motif for FIV assembly by introducing a series of amino acid substitutions into this sequence and studying their effect on in vivo and in vitro Gag assembly, CA oligomerization, mature virion production, and viral infectivity. Our results demonstrate that the Y176/L177 motif in FIV CA helix 9 is essential for Gag assembly and CA oligomerization. Notably, mutations converting the FIV CA Y176/L177 motif into the HIV-1 WM and EIAV FL sequences allow substantial particle production and viral replication in feline cells.
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Smaga SS, Xu C, Summers BJ, Digianantonio KM, Perilla JR, Xiong Y. MxB Restricts HIV-1 by Targeting the Tri-hexamer Interface of the Viral Capsid. Structure 2019; 27:1234-1245.e5. [PMID: 31155311 PMCID: PMC7183857 DOI: 10.1016/j.str.2019.04.015] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Revised: 04/15/2019] [Accepted: 04/24/2019] [Indexed: 11/21/2022]
Abstract
The human antiviral protein MxB is a restriction factor that fights HIV infection. Previous experiments have demonstrated that MxB targets the HIV capsid, a protein shell that protects the viral genome. To make the conical-shaped capsid, HIV CA proteins are organized into a lattice composed of hexamer and pentamer building blocks, providing many interfaces for host proteins to recognize. Through extensive biochemical and biophysical studies and molecular dynamics simulations, we show that MxB is targeting the HIV capsid by recognizing the region created at the intersection of three CA hexamers. We are further able to map this interaction to a few CA residues, located in a negatively charged well at the interface between the three CA hexamers. This work provides detailed residue-level mapping of the targeted capsid interface and how MxB interacts. This information could inspire the development of capsid-targeting therapies for HIV.
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Affiliation(s)
- Sarah Sierra Smaga
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA
| | - Chaoyi Xu
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716, USA
| | - Brady James Summers
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA
| | | | - Juan R Perilla
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716, USA
| | - Yong Xiong
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA.
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A Novel Phenotype Links HIV-1 Capsid Stability to cGAS-Mediated DNA Sensing. J Virol 2019; 93:JVI.00706-19. [PMID: 31167922 DOI: 10.1128/jvi.00706-19] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Accepted: 05/19/2019] [Indexed: 01/27/2023] Open
Abstract
The HIV-1 capsid executes essential functions that are regulated by capsid stability and host factors. In contrast to increasing knowledge on functional roles of capsid-interacting host proteins during postentry steps, less is known about capsid stability and its impact on intracellular events. Here, using the antiviral compound PF-3450074 (PF74) as a probe for capsid function, we uncovered a novel phenotype of capsid stability that has a profound effect on innate sensing of viral DNA by the DNA sensor cGAS. A single mutation, R143A, in the capsid protein conferred resistance to high concentrations of PF74, without affecting capsid binding to PF74. A cell-free assay showed that the R143A mutant partially counteracted the capsid-destabilizing activity of PF74, pointing to capsid stabilization as a resistance mechanism for the R143A mutant. In monocytic THP-1 cells, the R143A virus, but not the wild-type virus, suppressed cGAS-dependent innate immune activation. These results suggest that capsid stabilization improves the shielding of viral DNA from innate sensing. We found that a naturally occurring transmitted founder (T/F) variant shares the same properties as the R143A mutant with respect to PF74 resistance and DNA sensing. Imaging assays revealed delayed uncoating kinetics of this T/F variant and the R143A mutant. All these phenotypes of this T/F variant were controlled by a genetic polymorphism located at the trimeric interface between capsid hexamers, thus linking these capsid-dependent properties. Overall, this work functionally connects capsid stability to innate sensing of viral DNA and reveals naturally occurring phenotypic variation in HIV-1 capsid stability.IMPORTANCE The HIV-1 capsid, which is made from individual viral capsid proteins (CA), is a target for a number of antiviral compounds, including the small-molecule inhibitor PF74. In the present study, we utilized PF74 to identify a transmitted/founder (T/F) strain that shows increased capsid stability. Interestingly, PF74-resistant variants prevented cGAS-dependent innate immune activation under a condition where the other T/F strains induced type I interferon. These observations thus reveal a new CA-specific phenotype that couples capsid stability to viral DNA recognition by cytosolic DNA sensors.
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127
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Pak AJ, Grime JMA, Yu A, Voth GA. Off-Pathway Assembly: A Broad-Spectrum Mechanism of Action for Drugs That Undermine Controlled HIV-1 Viral Capsid Formation. J Am Chem Soc 2019; 141:10214-10224. [PMID: 31244184 PMCID: PMC6739737 DOI: 10.1021/jacs.9b01413] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Indexed: 12/21/2022]
Abstract
The early and late stages of human immunodeficiency virus (HIV) replication are orchestrated by the capsid (CA) protein, which self-assembles into a conical protein shell during viral maturation. Small molecule drugs known as capsid inhibitors (CIs) impede the highly regulated activity of CA. Intriguingly, a few CIs, such as PF-3450074 (PF74) and GS-CA1, exhibit effects at multiple stages of the viral lifecycle at effective concentrations in the pM to nM regimes, while the majority of CIs target a single stage of the viral lifecycle and are effective at nM to μM concentrations. In this work, we use coarse-grained molecular dynamics simulations to elucidate the molecular mechanisms that enable CIs to have such curious broad-spectrum activity. Our quantitatively analyzed findings show that CIs can have a profound impact on the hierarchical self-assembly of CA by perturbing populations of small CA oligomers. The self-assembly process is accelerated by the emergence of alternative assembly pathways that favor the rapid incorporation of CA pentamers, and leads to increased structural pleomorphism in mature capsids. Two relevant phenotypes are observed: (1) eccentric capsid formation that may fail to encase the viral genome and (2) rapid disassembly of the capsid, which express at late and early stages of infection, respectively. Finally, our study emphasizes the importance of adopting a dynamical perspective on inhibitory mechanisms and provides a basis for the design of future therapeutics that are effective at low stoichiometric ratios of drug to protein.
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Affiliation(s)
- Alexander J. Pak
- Department of Chemistry, Institute for Biophysical Dynamics,
and James Franck Institute, The University
of Chicago, Chicago, Illinois 60637, United States
| | - John M. A. Grime
- Department of Chemistry, Institute for Biophysical Dynamics,
and James Franck Institute, The University
of Chicago, Chicago, Illinois 60637, United States
| | - Alvin Yu
- Department of Chemistry, Institute for Biophysical Dynamics,
and James Franck Institute, The University
of Chicago, Chicago, Illinois 60637, United States
| | - Gregory A. Voth
- Department of Chemistry, Institute for Biophysical Dynamics,
and James Franck Institute, The University
of Chicago, Chicago, Illinois 60637, United States
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128
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Ferris AL, Wells DW, Guo S, Del Prete GQ, Swanstrom AE, Coffin JM, Wu X, Lifson JD, Hughes SH. Clonal expansion of SIV-infected cells in macaques on antiretroviral therapy is similar to that of HIV-infected cells in humans. PLoS Pathog 2019; 15:e1007869. [PMID: 31291371 PMCID: PMC6619828 DOI: 10.1371/journal.ppat.1007869] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Accepted: 05/24/2019] [Indexed: 12/11/2022] Open
Abstract
Clonal expansion of HIV infected cells plays an important role in the formation and persistence of the reservoir that allows the virus to persist, in DNA form, despite effective antiretroviral therapy. We used integration site analysis to ask if there is a similar clonal expansion of SIV infected cells in macaques. We show that the distribution of HIV and SIV integration sites in vitro is similar and that both viruses preferentially integrate in many of the same genes. We obtained approximately 8000 integration sites from blood samples taken from SIV-infected macaques prior to the initiation of ART, and from blood, spleen, and lymph node samples taken at necropsy. Seven clones were identified in the pre-ART samples; one persisted for a year on ART. An additional 100 clones were found only in on-ART samples; a number of these clones were found in more than one tissue. The timing and extent of clonal expansion of SIV-infected cells in macaques and HIV-infected cells in humans is quite similar. This suggests that SIV-infected macaques represent a useful model of the clonal expansion of HIV infected cells in humans that can be used to evaluate strategies intended to control or eradicate the viral reservoir.
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Affiliation(s)
- Andrea L. Ferris
- HIV Dynamics and Replication Program, National Cancer Institute Frederick, National Institutes of Health, Frederick, MD, United States of America
| | - David W. Wells
- Cancer Research Technology Program, Leidos Biomedical Research Inc., Frederick National Laboratory for Cancer Research, Frederick MD, United States of America
| | - Shuang Guo
- Cancer Research Technology Program, Leidos Biomedical Research Inc., Frederick National Laboratory for Cancer Research, Frederick MD, United States of America
| | - Gregory Q. Del Prete
- AIDS and Cancer Virus Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, MD, United States of America
| | - Adrienne E. Swanstrom
- AIDS and Cancer Virus Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, MD, United States of America
| | - John M. Coffin
- Department of Molecular Biology and Microbiology, Tufts University, Boston MA, United States of America
| | - Xiaolin Wu
- Cancer Research Technology Program, Leidos Biomedical Research Inc., Frederick National Laboratory for Cancer Research, Frederick MD, United States of America
| | - Jeffrey D. Lifson
- AIDS and Cancer Virus Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, MD, United States of America
| | - Stephen H. Hughes
- HIV Dynamics and Replication Program, National Cancer Institute Frederick, National Institutes of Health, Frederick, MD, United States of America
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Firrito C, Bertelli C, Vanzo T, Chande A, Pizzato M. SERINC5 as a New Restriction Factor for Human Immunodeficiency Virus and Murine Leukemia Virus. Annu Rev Virol 2019; 5:323-340. [PMID: 30265629 DOI: 10.1146/annurev-virology-092917-043308] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
SERINC genes encode for homologous multipass transmembrane proteins with unknown cellular function, despite being highly conserved across eukaryotes. Among the five SERINC genes found in humans, SERINC5 was shown to act as a powerful inhibitor of retroviruses. It is efficiently incorporated into virions and blocks the penetration of the viral core into target cells, by impairing the fusion process with a yet unclear mechanism. SERINC5 was also found to promote human immunodeficiency virus 1 (HIV-1) virion neutralization by antibodies, indicating a pleiotropic activity, which remains mostly unexplored. Counteracting factors have emerged independently in at least three retrovirus lineages, underscoring their fundamental importance during retrovirus evolution. Nef and S2 of primate and equine lentiviruses, and glycoGag of gammaretroviruses, act similarly by targeting SERINC5 to endosomes and excluding it from virions. Here, we discuss the features that distinguish SERINC5 from other known restriction factors, delineating a yet unique class of antiviral inhibitors.
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Affiliation(s)
- Claudia Firrito
- Centre for Integrative Biology, University of Trento, 38123 Trento, Italy ; , , ,
| | - Cinzia Bertelli
- Centre for Integrative Biology, University of Trento, 38123 Trento, Italy ; , , ,
| | - Teresa Vanzo
- Centre for Integrative Biology, University of Trento, 38123 Trento, Italy ; , , ,
| | - Ajit Chande
- Department of Biological Sciences, Indian Institute of Science Education and Research Bhopal, Bhopal 462 066, Madhya Pradesh, India;
| | - Massimo Pizzato
- Centre for Integrative Biology, University of Trento, 38123 Trento, Italy ; , , ,
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130
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Balasubramaniam M, Pandhare J, Dash C. Immune Control of HIV. JOURNAL OF LIFE SCIENCES (WESTLAKE VILLAGE, CALIF.) 2019; 1:4-37. [PMID: 31468033 PMCID: PMC6714987] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The human immunodeficiency virus (HIV) infection of the immune cells expressing the cluster of differentiation 4 cell surface glycoprotein (CD4+ cells) causes progressive decline of the immune system and leads to the acquired immunodeficiency syndrome (AIDS). The ongoing global HIV/AIDS pandemic has already claimed over 35 million lives. Even after 37 years into the epidemic, neither a cure is available for the 37 million people living with HIV (PLHIV) nor is a vaccine discovered to avert the millions of new HIV infections that continue to occur each year. If left untreated, HIV infection typically progresses to AIDS and, ultimately, causes death in a majority of PLHIV. The recommended combination antiretroviral therapy (cART) suppresses virus replication and viremia, prevents or delays progression to AIDS, reduces transmission rates, and lowers HIV-associated mortality and morbidity. However, because cART does not eliminate HIV, and an enduring pool of infected resting memory CD4+ T cells (latent HIV reservoir) is established early on, any interruption to cART leads to a relapse of viremia and disease progression. Hence, strict adherence to a life-long cART regimen is mandatory for managing HIV infection in PLHIV. The HIV-1-specific cytotoxic T cells expressing the CD8 glycoprotein (CD8+ CTL) limit the virus replication in vivo by recognizing the viral antigens presented by human leukocyte antigen (HLA) class I molecules on the infected cell surface and killing those cells. Nevertheless, CTLs fail to durably control HIV-1 replication and disease progression in the absence of cART. Intriguingly, <1% of cART-naive HIV-infected individuals called elite controllers/HIV controllers (HCs) exhibit the core features that define a HIV-1 "functional cure" outcome in the absence of cART: durable viral suppression to below the limit of detection, long-term non-progression to AIDS, and absence of viral transmission. Robust HIV-1-specific CTL responses and prevalence of protective HLA alleles associated with enduring HIV-1 control have been linked to the HC phenotype. An understanding of the molecular mechanisms underlying the CTL-mediated suppression of HIV-1 replication and disease progression in HCs carrying specific protective HLA alleles may yield promising insights towards advancing the research on HIV cure and prophylactic HIV vaccine.
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Affiliation(s)
- Muthukumar Balasubramaniam
- Center for AIDS Health Disparities Research, Meharry Medical College, Nashville, TN – 37208. USA
- Department of Biochemistry and Cancer Biology, Meharry Medical College, Nashville, TN – 37208. USA
| | - Jui Pandhare
- Center for AIDS Health Disparities Research, Meharry Medical College, Nashville, TN – 37208. USA
- School of Graduate Studies and Research, Meharry Medical College, Nashville, TN – 37208. USA
| | - Chandravanu Dash
- Center for AIDS Health Disparities Research, Meharry Medical College, Nashville, TN – 37208. USA
- Department of Biochemistry and Cancer Biology, Meharry Medical College, Nashville, TN – 37208. USA
- School of Graduate Studies and Research, Meharry Medical College, Nashville, TN – 37208. USA
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131
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Jang S, Cook NJ, Pye VE, Bedwell GJ, Dudek AM, Singh PK, Cherepanov P, Engelman AN. Differential role for phosphorylation in alternative polyadenylation function versus nuclear import of SR-like protein CPSF6. Nucleic Acids Res 2019; 47:4663-4683. [PMID: 30916345 PMCID: PMC6511849 DOI: 10.1093/nar/gkz206] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Revised: 02/12/2019] [Accepted: 03/18/2019] [Indexed: 12/20/2022] Open
Abstract
Cleavage factor I mammalian (CFIm) complex, composed of cleavage and polyadenylation specificity factor 5 (CPSF5) and serine/arginine-like protein CPSF6, regulates alternative polyadenylation (APA). Loss of CFIm function results in proximal polyadenylation site usage, shortening mRNA 3' untranslated regions (UTRs). Although CPSF6 plays additional roles in human disease, its nuclear translocation mechanism remains unresolved. Two β-karyopherins, transportin (TNPO) 1 and TNPO3, can bind CPSF6 in vitro, and we demonstrate here that while the TNPO1 binding site is dispensable for CPSF6 nuclear import, the arginine/serine (RS)-like domain (RSLD) that mediates TNPO3 binding is critical. The crystal structure of the RSLD-TNPO3 complex revealed potential CPSF6 interaction residues, which were confirmed to mediate TNPO3 binding and CPSF6 nuclear import. Both binding and nuclear import were independent of RSLD phosphorylation, though a hyperphosphorylated mimetic mutant failed to bind TNPO3 and mislocalized to the cell cytoplasm. Although hypophosphorylated CPSF6 largely supported normal polyadenylation site usage, a significant number of mRNAs harbored unnaturally extended 3' UTRs, similar to what is observed when other APA regulators, such as CFIIm component proteins, are depleted. Our results clarify the mechanism of CPSF6 nuclear import and highlight differential roles for RSLD phosphorylation in nuclear translocation versus regulation of APA.
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Affiliation(s)
- Sooin Jang
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, MA 02215, USA
- Department of Medicine, Harvard Medical School, Boston, MA 02115, USA
| | - 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
| | - Gregory J Bedwell
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, MA 02215, USA
- Department of Medicine, Harvard Medical School, Boston, MA 02115, USA
| | - Amanda M Dudek
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, MA 02215, USA
- Department of Medicine, Harvard Medical School, Boston, MA 02115, USA
| | - Parmit K Singh
- 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
| | - 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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132
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D Urbano V, De Crignis E, Re MC. Host Restriction Factors and Human Immunodeficiency Virus (HIV-1): A Dynamic Interplay Involving All Phases of the Viral Life Cycle. Curr HIV Res 2019; 16:184-207. [PMID: 30117396 DOI: 10.2174/1570162x16666180817115830] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2018] [Revised: 07/31/2018] [Accepted: 08/09/2018] [Indexed: 02/08/2023]
Abstract
Mammalian cells have evolved several mechanisms to prevent or block lentiviral infection and spread. Among the innate immune mechanisms, the signaling cascade triggered by type I interferon (IFN) plays a pivotal role in limiting the burden of HIV-1. In the presence of IFN, human cells upregulate the expression of a number of genes, referred to as IFN-stimulated genes (ISGs), many of them acting as antiviral restriction factors (RFs). RFs are dominant proteins that target different essential steps of the viral cycle, thereby providing an early line of defense against the virus. The identification and characterization of RFs have provided unique insights into the molecular biology of HIV-1, further revealing the complex host-pathogen interplay that characterizes the infection. The presence of RFs drove viral evolution, forcing the virus to develop specific proteins to counteract their activity. The knowledge of the mechanisms that prevent viral infection and their viral counterparts may offer new insights to improve current antiviral strategies. This review provides an overview of the RFs targeting HIV-1 replication and the mechanisms that regulate their expression as well as their impact on viral replication and the clinical course of the disease.
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Affiliation(s)
- Vanessa D Urbano
- Retrovirus Laboratory, Operative Unit of Clinical Microbiology, S. Orsola-Malpighi University Hospital, Bologna, Italy
| | - Elisa De Crignis
- Retrovirus Laboratory, Operative Unit of Clinical Microbiology, S. Orsola-Malpighi University Hospital, Bologna, Italy
| | - Maria Carla Re
- Retrovirus Laboratory, Operative Unit of Clinical Microbiology, S. Orsola-Malpighi University Hospital, Bologna, Italy
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133
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Saito A, Ode H, Nohata K, Ohmori H, Nakayama EE, Iwatani Y, Shioda T. HIV-1 is more dependent on the K182 capsid residue than HIV-2 for interactions with CPSF6. Virology 2019; 532:118-126. [PMID: 31071616 DOI: 10.1016/j.virol.2019.04.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Revised: 04/23/2019] [Accepted: 04/25/2019] [Indexed: 12/12/2022]
Abstract
The HIV-1 capsid (CA) utilizes CPSF6 for nuclear entry and integration site targeting. Previous studies demonstrated that the HIV-1 CA C-terminal domain (CTD) contains a highly conserved K182 residue involved in interaction with CPSF6. In contrast, certain HIV-2 strains possess a substitution at this residue (K182R). To assess whether CA-CPSF6 interaction via the CA CTD is conserved among primate lentiviruses, we examined resistance of several HIV-1- and HIV-2-lineage viruses to a truncated form of CPSF6, CPSF6-358. The results demonstrated that viruses belonging to the HIV-2-lineage maintain interaction with CPSF6 regardless of the presence of the K182R substitution, in contrast to the case with HIV-1-lineage viruses. Our structure-guided mutagenesis indicated that the differential requirement for CA-CPSF6 interaction is regulated in part by residues near the 182nd amino acid of CA. These results demonstrate a previously unrecognized distinction between HIV-1 and HIV-2, which may reflect differences in their evolutionary histories.
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Affiliation(s)
- Akatsuki Saito
- Research Institute for Microbial Diseases, Osaka University, Osaka, Japan.
| | - Hirotaka Ode
- Clinical Research Center, National Hospital Organization Nagoya Medical Center, Nagoya, Japan
| | - Kyotaro Nohata
- Research Institute for Microbial Diseases, Osaka University, Osaka, Japan
| | - Hisaki Ohmori
- Research Institute for Microbial Diseases, Osaka University, Osaka, Japan
| | - Emi E Nakayama
- Research Institute for Microbial Diseases, Osaka University, Osaka, Japan
| | - Yasumasa Iwatani
- Clinical Research Center, National Hospital Organization Nagoya Medical Center, Nagoya, Japan; Division of Basic Medicine, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Tatsuo Shioda
- Research Institute for Microbial Diseases, Osaka University, Osaka, Japan
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Novikova M, Zhang Y, Freed EO, Peng K. Multiple Roles of HIV-1 Capsid during the Virus Replication Cycle. Virol Sin 2019; 34:119-134. [PMID: 31028522 PMCID: PMC6513821 DOI: 10.1007/s12250-019-00095-3] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2018] [Accepted: 01/16/2019] [Indexed: 11/29/2022] Open
Abstract
Human immunodeficiency virus-1 capsid (HIV-1 CA) is involved in different stages of the viral replication cycle. During virion assembly, CA drives the formation of the hexameric lattice in immature viral particles, while in mature virions CA monomers assemble in cone-shaped cores surrounding the viral RNA genome and associated proteins. In addition to its functions in late stages of the viral replication cycle, CA plays key roles in a number of processes during early phases of HIV-1 infection including trafficking, uncoating, recognition by host cellular proteins and nuclear import of the viral pre-integration complex. As a result of efficient cooperation of CA with other viral and cellular proteins, integration of the viral genetic material into the host genome, which is an essential step for productive viral infection, successfully occurs. In this review, we will summarize available data on CA functions in HIV-1 replication, describing in detail its roles in late and early phases of the viral replication cycle.
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Affiliation(s)
- Mariia Novikova
- Virus-Cell Interaction Section, HIV Dynamics and Replication Program, Center for Cancer Research, National Cancer Institute, Frederick, MD, 21702, USA
| | - Yulan Zhang
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, 430071, China
| | - Eric O Freed
- Virus-Cell Interaction Section, HIV Dynamics and Replication Program, Center for Cancer Research, National Cancer Institute, Frederick, MD, 21702, USA.
| | - Ke Peng
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, 430071, China.
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135
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CA Mutation N57A Has Distinct Strain-Specific HIV-1 Capsid Uncoating and Infectivity Phenotypes. J Virol 2019; 93:JVI.00214-19. [PMID: 30814280 DOI: 10.1128/jvi.00214-19] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Accepted: 02/15/2019] [Indexed: 12/20/2022] Open
Abstract
The ability of human immunodeficiency virus type 1 (HIV-1) to transduce nondividing cells is key to infecting terminally differentiated macrophages, which can serve as a long-term reservoir of HIV-1 infection. The mutation N57A in the viral CA protein renders HIV-1 cell cycle dependent, allowing examination of HIV-1 infection of nondividing cells. Here, we show that the N57A mutation confers a postentry infectivity defect that significantly differs in magnitude between the common lab-adapted molecular clones HIV-1NL4-3 (>10-fold) and HIV-1LAI (2- to 5-fold) in multiple human cell lines and primary CD4+ T cells. Capsid permeabilization and reverse transcription are altered when N57A is incorporated into HIV-1NL4-3 but not HIV-1LAI The N57A infectivity defect is significantly exacerbated in both virus strains in the presence of cyclosporine (CsA), indicating that N57A infectivity is dependent upon CA interacting with host factor cyclophilin A (CypA). Adaptation of N57A HIV-1LAI selected for a second CA mutation, G94D, which rescued the N57A infectivity defect in HIV-1LAI but not HIV-1NL4-3 The rescue of N57A by G94D in HIV-1LAI is abrogated by CsA treatment in some cell types, demonstrating that this rescue is CypA dependent. An examination of over 40,000 HIV-1 CA sequences revealed that the four amino acids that differ between HIV-1NL4-3 and HIV-1LAI CA are polymorphic, and the residues at these positions in the two strains are widely prevalent in clinical isolates. Overall, a few polymorphic amino acid differences between two closely related HIV-1 molecular clones affect the phenotype of capsid mutants in different cell types.IMPORTANCE The specific mechanisms by which HIV-1 infects nondividing cells are unclear. A mutation in the HIV-1 capsid protein abolishes the ability of the virus to infect nondividing cells, serving as a tool to examine cell cycle dependence of HIV-1 infection. We have shown that two widely used HIV-1 molecular clones exhibit significantly different N57A infectivity phenotypes due to fewer than a handful of CA amino acid differences and that these clones are both represented in HIV-infected individuals. As such minor differences in closely related HIV-1 strains may impart significant infectivity differences, careful consideration should be given to drawing conclusions from one particular HIV-1 clone. This study highlights the potential for significant variation in results with the use of multiple strains and possible unanticipated effects of natural polymorphisms.
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136
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Balasubramaniam M, Zhou J, Addai A, Martinez P, Pandhare J, Aiken C, Dash C. PF74 Inhibits HIV-1 Integration by Altering the Composition of the Preintegration Complex. J Virol 2019; 93:e01741-18. [PMID: 30567984 PMCID: PMC6401427 DOI: 10.1128/jvi.01741-18] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Accepted: 12/06/2018] [Indexed: 11/20/2022] Open
Abstract
The HIV-1 capsid protein (CA) facilitates reverse transcription and nuclear entry of the virus. However, CA's role in post-nuclear entry steps remains speculative. We describe a direct link between CA and integration by employing the capsid inhibitor PF74 as a probe coupled with the biochemical analysis of HIV-1 preintegration complexes (PICs) isolated from acutely infected cells. At a low micromolar concentration, PF74 potently inhibited HIV-1 infection without affecting reverse transcription. Surprisingly, PF74 markedly reduced proviral integration owing to inhibition of nuclear entry and/or integration. However, a 2-fold reduction in nuclear entry by PF74 did not quantitatively correlate with the level of antiviral activity. Titration of PF74 against the integrase inhibitor raltegravir showed an additive antiviral effect that is dependent on a block at the post-nuclear entry step. PF74's inhibitory effect was not due to the formation of defective viral DNA ends or a delay in integration, suggesting that the compound inhibits PIC-associated integration activity. Unexpectedly, PICs recovered from cells infected in the presence of PF74 exhibited elevated integration activity. PF74's effect on PIC activity is CA specific since the compound did not increase the integration activity of PICs of a PF74-resistant HIV-1 CA mutant. Sucrose gradient-based fractionation studies revealed that PICs assembled in the presence of PF74 contained lower levels of CA, suggesting a negative association between CA and PIC-associated integration activity. Finally, the addition of a CA-specific antibody or PF74 inhibited PIC-associated integration activity. Collectively, our results demonstrate that PF74's targeting of PIC-associated CA results in impaired HIV-1 integration.IMPORTANCE Antiretroviral therapy (ART) that uses various combinations of small molecule inhibitors has been highly effective in controlling HIV. However, the drugs used in the ART regimen are expensive, cause side effects, and face viral resistance. The HIV-1 CA plays critical roles in the virus life cycle and is an attractive therapeutic target. While currently there is no CA-based therapy, highly potent CA-specific inhibitors are being developed as a new class of antivirals. Efforts to develop a CA-targeted therapy can be aided through a clear understanding of the role of CA in HIV-1 infection. CA is well established to coordinate reverse transcription and nuclear entry of the virus. However, the role of CA in post-nuclear entry steps of HIV-1 infection is poorly understood. We show that a CA-specific drug PF74 inhibits HIV-1 integration revealing a novel role of this multifunctional viral protein in a post-nuclear entry step of HIV-1 infection.
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Affiliation(s)
- Muthukumar Balasubramaniam
- Center for AIDS Health Disparities Research, Department of Biochemistry and Cancer Biology, Meharry Medical College, Nashville, Tennessee, USA
| | - Jing Zhou
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Amma Addai
- Center for AIDS Health Disparities Research, Department of Biochemistry and Cancer Biology, Meharry Medical College, Nashville, Tennessee, USA
| | - Phillip Martinez
- Center for AIDS Health Disparities Research, Department of Biochemistry and Cancer Biology, Meharry Medical College, Nashville, Tennessee, USA
| | - Jui Pandhare
- Center for AIDS Health Disparities Research, Department of Biochemistry and Cancer Biology, Meharry Medical College, Nashville, Tennessee, USA
| | - Christopher Aiken
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Chandravanu Dash
- Center for AIDS Health Disparities Research, Department of Biochemistry and Cancer Biology, Meharry Medical College, Nashville, Tennessee, USA
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137
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Novel Intersubunit Interaction Critical for HIV-1 Core Assembly Defines a Potentially Targetable Inhibitor Binding Pocket. mBio 2019; 10:mBio.02858-18. [PMID: 30862755 PMCID: PMC6414707 DOI: 10.1128/mbio.02858-18] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Precise assembly and disassembly of the HIV-1 capsid core are key to the success of viral replication. The forces that govern capsid core formation and dissociation involve intricate interactions between pentamers and hexamers formed by HIV-1 CA. We identified one particular interaction between E28 of one CA and K30′ of the adjacent CA that appears more frequently in pentamers than in hexamers and that is important for capsid assembly. Targeting the corresponding site could lead to the development of antivirals which disrupt this interaction and affect capsid assembly. HIV-1 capsid protein (CA) plays critical roles in both early and late stages of the viral replication cycle. Mutagenesis and structural experiments have revealed that capsid core stability significantly affects uncoating and initiation of reverse transcription in host cells. This has led to efforts in developing antivirals targeting CA and its assembly, although none of the currently identified compounds are used in the clinic for treatment of HIV infection. A specific interaction that is primarily present in pentameric interfaces in the HIV-1 capsid core was identified and is reported to be important for CA assembly. This is shown by multidisciplinary characterization of CA site-directed mutants using biochemical analysis of virus-like particle formation, transmission electron microscopy of in vitro assembly, crystallographic studies, and molecular dynamic simulations. The data are consistent with a model where a hydrogen bond between CA residues E28 and K30′ from neighboring N-terminal domains (CANTDs) is important for CA pentamer interactions during core assembly. This pentamer-preferred interaction forms part of an N-terminal domain interface (NDI) pocket that is amenable to antiviral targeting.
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138
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Zuliani-Alvarez L, Towers GJ. Identifying a nuclear passport for HIV. eLife 2019; 8:45580. [PMID: 30834893 PMCID: PMC6400497 DOI: 10.7554/elife.45580] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Accepted: 03/01/2019] [Indexed: 11/13/2022] Open
Abstract
Identification of a protein that pulls HIV into the nucleus explains a key step in HIV infection.
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Affiliation(s)
| | - Greg J Towers
- Division of Infection and Immunity, University College London, London, United Kingdom
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139
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Bejarano DA, Peng K, Laketa V, Börner K, Jost KL, Lucic B, Glass B, Lusic M, Müller B, Kräusslich HG. HIV-1 nuclear import in macrophages is regulated by CPSF6-capsid interactions at the nuclear pore complex. eLife 2019; 8:41800. [PMID: 30672737 PMCID: PMC6400501 DOI: 10.7554/elife.41800] [Citation(s) in RCA: 118] [Impact Index Per Article: 23.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Accepted: 01/16/2019] [Indexed: 12/19/2022] Open
Abstract
Nuclear entry of HIV-1 replication complexes through intact nuclear pore complexes is critical for successful infection. The host protein cleavage-and-polyadenylation-specificity-factor-6 (CPSF6) has been implicated in different stages of early HIV-1 replication. Applying quantitative microscopy of HIV-1 reverse-transcription and pre-integration-complexes (RTC/PIC), we show that CPSF6 is strongly recruited to nuclear replication complexes but absent from cytoplasmic RTC/PIC in primary human macrophages. Depletion of CPSF6 or lack of CPSF6 binding led to accumulation of HIV-1 subviral complexes at the nuclear envelope of macrophages and reduced infectivity. Two-color stimulated-emission-depletion microscopy indicated that under these circumstances HIV-1 complexes are retained inside the nuclear pore and undergo CA-multimer dependent CPSF6 clustering adjacent to the nuclear basket. We propose that nuclear entry of HIV-1 subviral complexes in macrophages is mediated by consecutive binding of Nup153 and CPSF6 to the hexameric CA lattice. Viruses are miniscule parasites that hijack the resources of a cell to make more of themselves. For many, this involves getting inside the nucleus, the fortress that protects the cell’s genetic information. To do so, viruses need to first find a way through a double-layered membrane called the nuclear envelope, which only opens up when a cell divides. Yet, the human immunodeficiency virus type 1 (HIV-1) can infect cells that no longer divide, and in which the nucleus’ walls never come down. The virus cores then head for the nuclear pores, heavily guarded holes in the nuclear envelope that allow the cell's own molecules to go in and out of the nucleus. But HIV-1 is too big to fit through, as its genetic information is encased in a capsid, a coat made of a complex assembly of proteins. However, research shows that these capsid proteins can bind to host proteins at the pore or even inside the nucleus. For example, the capsid protein can recognize the pore protein Nup153, or the nuclear protein CPSF6. These interactions could help the virus make its way in, but how these events unfold is still unclear. To explore this, Bejarano, Peng et al. attached fluorescent labels to HIV-1 and watched as it infected non-dividing cells. Rather than completely get rid of their capsid before they crossed the pores, the virus particles hung on to a large part of their lattice. This remaining coat then attached to CPSF6; when this protein was missing or could not bind to capsid proteins, the viral complexes got stuck in the nuclear pores. This suggests that the capsid lattice could first interact with Nup153 inside the pores: then, CPSF6 would take over, knocking Nup153 away and pulling HIV-1 into the nucleus. Armed with this knowledge, virologists and drug developers could try to block HIV-1 from entering the cell’s nucleus; they could also start to dissect how drugs that target the HIV-1 capsid work. Ultimately, HIV-1 may serve as a model to unravel how large objects can pass the nuclear pore, which may help us understand how molecules are constantly trafficked in and out of the nucleus.
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Affiliation(s)
| | - Ke Peng
- Department of Infectious Diseases Virology, University of Heidelberg, Heidelberg, Germany
| | - Vibor Laketa
- Department of Infectious Diseases Virology, University of Heidelberg, Heidelberg, Germany.,German Center for Infection Research, Heidelberg, Germany
| | - Kathleen Börner
- Department of Infectious Diseases Virology, University of Heidelberg, Heidelberg, Germany.,German Center for Infection Research, Heidelberg, Germany
| | - K Laurence Jost
- Department of Infectious Diseases Virology, University of Heidelberg, Heidelberg, Germany.,German Center for Infection Research, Heidelberg, Germany
| | - Bojana Lucic
- German Center for Infection Research, Heidelberg, Germany.,Department of Infectious Diseases, Integrative Virology, University of Heidelberg, Heidelberg, Germany
| | - Bärbel Glass
- Department of Infectious Diseases Virology, University of Heidelberg, Heidelberg, Germany
| | - Marina Lusic
- German Center for Infection Research, Heidelberg, Germany.,Department of Infectious Diseases, Integrative Virology, University of Heidelberg, Heidelberg, Germany
| | - Barbara Müller
- Department of Infectious Diseases Virology, University of Heidelberg, Heidelberg, Germany
| | - Hans-Georg Kräusslich
- Department of Infectious Diseases Virology, University of Heidelberg, Heidelberg, Germany
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140
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Minute Virus of Canines NP1 Protein Interacts with the Cellular Factor CPSF6 To Regulate Viral Alternative RNA Processing. J Virol 2019; 93:JVI.01530-18. [PMID: 30355695 DOI: 10.1128/jvi.01530-18] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2018] [Accepted: 10/21/2018] [Indexed: 12/21/2022] Open
Abstract
The NP1 protein of minute virus of canines (MVC) governs production of the viral capsid proteins via its role in pre-mRNA processing. NP1 suppresses polyadenylation and cleavage at its internal site, termed the proximal polyadenylation (pA)p site, to allow accumulation of RNAs that extend into the capsid gene, and it enhances splicing of the upstream adjacent third intron, which is necessary to properly enter the capsid protein open reading frame. We find the (pA)p region to be complex. It contains redundant classical cis-acting signals necessary for the cleavage and polyadenylation reaction and splicing of the adjacent upstream third intron, as well as regions outside the classical motifs that are necessary for responding to NP1. NP1, but not processing mutants of NP1, bound to MVC RNA directly. The cellular RNA processing factor CPSF6 interacted with NP1 in transfected cells and participated with NP1 to modulate its effects. These experiments further characterize the role of NP1 in parvovirus gene expression.IMPORTANCE The Parvovirinae are small nonenveloped icosahedral viruses that are important pathogens in many animal species, including humans. Unlike other parvoviruses, the bocavirus genus controls expression of its capsid proteins via alternative RNA processing, by both suppressing polyadenylation at an internal site, termed the proximal polyadenylation (pA)p site, and by facilitating splicing of an upstream adjacent intron. This regulation is mediated by a small genus-specific protein, NP1. Understanding the cis-acting targets of NP1, as well as the cellular factors with which it interacts, is necessary to more clearly understand this unique mode of parvovirus gene expression.
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141
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Petrillo C, Thorne LG, Unali G, Schiroli G, Giordano AMS, Piras F, Cuccovillo I, Petit SJ, Ahsan F, Noursadeghi M, Clare S, Genovese P, Gentner B, Naldini L, Towers GJ, Kajaste-Rudnitski A. Cyclosporine H Overcomes Innate Immune Restrictions to Improve Lentiviral Transduction and Gene Editing In Human Hematopoietic Stem Cells. Cell Stem Cell 2018; 23:820-832.e9. [PMID: 30416070 PMCID: PMC6292841 DOI: 10.1016/j.stem.2018.10.008] [Citation(s) in RCA: 75] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Revised: 08/09/2018] [Accepted: 10/02/2018] [Indexed: 01/01/2023]
Abstract
Innate immune factors may restrict hematopoietic stem cell (HSC) genetic engineering and contribute to broad individual variability in gene therapy outcomes. Here, we show that HSCs harbor an early, constitutively active innate immune block to lentiviral transduction that can be efficiently overcome by cyclosporine H (CsH). CsH potently enhances gene transfer and editing in human long-term repopulating HSCs by inhibiting interferon-induced transmembrane protein 3 (IFITM3), which potently restricts VSV glycoprotein-mediated vector entry. Importantly, individual variability in endogenous IFITM3 levels correlated with permissiveness of HSCs to lentiviral transduction, suggesting that CsH treatment will be useful for improving ex vivo gene therapy and standardizing HSC transduction across patients. Overall, our work unravels the involvement of innate pathogen recognition molecules in immune blocks to gene correction in primary human HSCs and highlights how these roadblocks can be overcome to develop innovative cell and gene therapies.
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Affiliation(s)
- Carolina Petrillo
- San Raffaele Telethon Institute for Gene Therapy, IRCCS San Raffaele Scientific Institute, Milan, MI 20132, Italy; Vita-Salute San Raffaele University, School of Medicine, Milan, MI 20132, Italy
| | - Lucy G Thorne
- Division of Infection and Immunity, University College London, London WC1E 6BT, UK
| | - Giulia Unali
- San Raffaele Telethon Institute for Gene Therapy, IRCCS San Raffaele Scientific Institute, Milan, MI 20132, Italy; Vita-Salute San Raffaele University, School of Medicine, Milan, MI 20132, Italy
| | - Giulia Schiroli
- San Raffaele Telethon Institute for Gene Therapy, IRCCS San Raffaele Scientific Institute, Milan, MI 20132, Italy
| | - Anna M S Giordano
- San Raffaele Telethon Institute for Gene Therapy, IRCCS San Raffaele Scientific Institute, Milan, MI 20132, Italy; Vita-Salute San Raffaele University, School of Medicine, Milan, MI 20132, Italy
| | - Francesco Piras
- San Raffaele Telethon Institute for Gene Therapy, IRCCS San Raffaele Scientific Institute, Milan, MI 20132, Italy; Vita-Salute San Raffaele University, School of Medicine, Milan, MI 20132, Italy
| | - Ivan Cuccovillo
- San Raffaele Telethon Institute for Gene Therapy, IRCCS San Raffaele Scientific Institute, Milan, MI 20132, Italy
| | - Sarah J Petit
- Division of Infection and Immunity, University College London, London WC1E 6BT, UK
| | - Fatima Ahsan
- Division of Infection and Immunity, University College London, London WC1E 6BT, UK
| | - Mahdad Noursadeghi
- Division of Infection and Immunity, University College London, London WC1E 6BT, UK
| | - Simon Clare
- Wellcome Trust Sanger Institute, Hinxton, Cambridgeshire CB10 1SA, UK
| | - Pietro Genovese
- San Raffaele Telethon Institute for Gene Therapy, IRCCS San Raffaele Scientific Institute, Milan, MI 20132, Italy
| | - Bernhard Gentner
- San Raffaele Telethon Institute for Gene Therapy, IRCCS San Raffaele Scientific Institute, Milan, MI 20132, Italy
| | - Luigi Naldini
- San Raffaele Telethon Institute for Gene Therapy, IRCCS San Raffaele Scientific Institute, Milan, MI 20132, Italy; Vita-Salute San Raffaele University, School of Medicine, Milan, MI 20132, Italy
| | - Greg J Towers
- Division of Infection and Immunity, University College London, London WC1E 6BT, UK
| | - Anna Kajaste-Rudnitski
- San Raffaele Telethon Institute for Gene Therapy, IRCCS San Raffaele Scientific Institute, Milan, MI 20132, Italy.
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142
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Dicks MDJ, Betancor G, Jimenez-Guardeño JM, Pessel-Vivares L, Apolonia L, Goujon C, Malim MH. Multiple components of the nuclear pore complex interact with the amino-terminus of MX2 to facilitate HIV-1 restriction. PLoS Pathog 2018; 14:e1007408. [PMID: 30496303 PMCID: PMC6264145 DOI: 10.1371/journal.ppat.1007408] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Accepted: 10/15/2018] [Indexed: 12/13/2022] Open
Abstract
Human myxovirus resistance 2 (MX2/MXB) is an interferon-induced post-entry inhibitor of human immunodeficiency virus type-1 (HIV-1) infection. While the precise mechanism of viral inhibition remains unclear, MX2 is localized to the nuclear envelope, and blocks the nuclear import of viral cDNAs. The amino-terminus of MX2 (N-MX2) is essential for anti-viral function, and mutation of a triple arginine motif at residues 11 to 13 abrogates anti-HIV-1 activity. In this study, we sought to investigate the role of N-MX2 in anti-viral activity by identifying functionally relevant host-encoded interaction partners through yeast-two-hybrid screening. Remarkably, five out of seven primary candidate interactors were nucleoporins or nucleoporin-like proteins, though none of these candidates were identified when screening with a mutant RRR11-13A N-MX2 fragment. Interactions were confirmed by co-immunoprecipitation, and RNA silencing experiments in cell lines and primary CD4+ T cells demonstrated that multiple components of the nuclear pore complex and nuclear import machinery can impact MX2 anti-viral activity. In particular, the phenylalanine-glycine (FG) repeat containing cytoplasmic filament nucleoporin NUP214, and transport receptor transportin-1 (TNPO1) were consistently required for full MX2, and interferon-mediated, anti-viral function. Both proteins were shown to interact with the triple arginine motif, and confocal fluorescence microscopy revealed that their simultaneous depletion resulted in diminished MX2 accumulation at the nuclear envelope. We therefore propose a model whereby multiple components of the nuclear import machinery and nuclear pore complex help position MX2 at the nuclear envelope to promote MX2-mediated restriction of HIV-1. The movement of large molecules into the cell nucleus is regulated at specific sites within the nuclear envelope termed nuclear pores. To infect cells productively, human immunodeficiency virus type-1 (HIV-1) must traverse the nuclear envelope to enable integration of the viral DNA into the genomic DNA of host cells. We, and others, have previously identified a cell-encoded protein, human myxovirus resistance 2 (MX2), which is expressed upon initiation of an innate immune response and prevents accumulation of HIV-1 DNA within the nucleus, thus imposing a block to infection. Here, we reveal that components of the nuclear pore complex, and nuclear import machinery, are required for MX2-dependent inhibition of HIV-1 infection. We show that MX2, which is localized at the cytoplasmic face of the nuclear envelope, interacts with multiple protein components of the nuclear pore complex, as well as transport receptor transportin-1, via a functionally required triple arginine motif at its amino-terminus. We speculate that these interactions facilitate MX2-mediated inhibition of HIV-1 nuclear import by situating the protein at the nuclear envelope.
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Affiliation(s)
- Matthew D. J. Dicks
- Department of Infectious Diseases, School of Immunology & Microbial Sciences, King’s College London, London, United Kingdom
| | - Gilberto Betancor
- Department of Infectious Diseases, School of Immunology & Microbial Sciences, King’s College London, London, United Kingdom
| | - Jose M. Jimenez-Guardeño
- Department of Infectious Diseases, School of Immunology & Microbial Sciences, King’s College London, London, United Kingdom
| | - Lucie Pessel-Vivares
- Department of Infectious Diseases, School of Immunology & Microbial Sciences, King’s College London, London, United Kingdom
| | - Luis Apolonia
- Department of Infectious Diseases, School of Immunology & Microbial Sciences, King’s College London, London, United Kingdom
| | - Caroline Goujon
- Department of Infectious Diseases, School of Immunology & Microbial Sciences, King’s College London, London, United Kingdom
| | - Michael H. Malim
- Department of Infectious Diseases, School of Immunology & Microbial Sciences, King’s College London, London, United Kingdom
- * E-mail:
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143
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IP6 Regulation of HIV Capsid Assembly, Stability, and Uncoating. Viruses 2018; 10:v10110640. [PMID: 30445742 PMCID: PMC6267275 DOI: 10.3390/v10110640] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Revised: 11/12/2018] [Accepted: 11/13/2018] [Indexed: 11/17/2022] Open
Abstract
The mechanisms that drive formation of the HIV capsid, first as an immature particle and then as a mature protein shell, remain incompletely understood. Recent discoveries of positively-charged rings in the immature and mature protein hexamer subunits that comprise them and their binding to the cellular metabolite inositol hexakisphosphate (IP6) have stimulated exciting new hypotheses. In this paper, we discuss how data from multiple structural and biochemical approaches are revealing potential roles for IP6 in the HIV-1 replication cycle from assembly to uncoating.
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144
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PF74 Reinforces the HIV-1 Capsid To Impair Reverse Transcription-Induced Uncoating. J Virol 2018; 92:JVI.00845-18. [PMID: 30089694 DOI: 10.1128/jvi.00845-18] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Accepted: 08/01/2018] [Indexed: 11/20/2022] Open
Abstract
The RNA genome of human immunodeficiency virus type 1 (HIV-1) is enclosed in a cone-shaped capsid shell that disassembles following cell entry via a process known as uncoating. During HIV-1 infection, the capsid is important for reverse transcription and entry of the virus into the target cell nucleus. The small molecule PF74 inhibits HIV-1 infection at early stages by binding to the capsid and perturbing uncoating. However, the mechanism by which PF74 alters capsid stability and reduces viral infection is presently unknown. Here, we show, using atomic force microscopy (AFM), that binding of PF74 to recombinant capsid-like assemblies and to HIV-1 isolated cores stabilizes the capsid in a concentration-dependent manner. At a PF74 concentration of 10 μM, the mechanical stability of the core is increased to a level similar to that of the intrinsically hyperstable capsid mutant E45A. PF74 also prevented the complete disassembly of HIV-1 cores normally observed during 24 h of reverse transcription. Specifically, cores treated with PF74 only partially disassembled: the main body of the capsid remained intact and stiff, and a cap-like structure dissociated from the narrow end of the core. Moreover, the internal coiled structure that was observed to form during reverse transcription in vitro persisted throughout the duration of the measurement (∼24 h). Our results provide direct evidence that PF74 directly stabilizes the HIV-1 capsid lattice, thereby permitting reverse transcription while interfering with a late step in uncoating.IMPORTANCE The capsid-binding small molecule PF74 inhibits HIV-1 infection at early stages and perturbs uncoating. However, the mechanism by which PF74 alters capsid stability and reduces viral infection is presently unknown. We recently introduced time-lapse atomic force microscopy to study the morphology and physical properties of HIV-1 cores during the course of reverse transcription. Here, we apply this AFM methodology to show that PF74 prevented the complete disassembly of HIV-1 cores normally observed during 24 h of reverse transcription. Specifically, cores with PF74 only partially disassembled: the main body of the capsid remained intact and stiff, but a cap-like structure dissociated from the narrow end of the core HIV-1. Our result provides direct evidence that PF74 directly stabilizes the HIV-1 capsid lattice.
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145
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Francis AC, Melikyan GB. Single HIV-1 Imaging Reveals Progression of Infection through CA-Dependent Steps of Docking at the Nuclear Pore, Uncoating, and Nuclear Transport. Cell Host Microbe 2018; 23:536-548.e6. [PMID: 29649444 DOI: 10.1016/j.chom.2018.03.009] [Citation(s) in RCA: 121] [Impact Index Per Article: 20.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Revised: 02/03/2018] [Accepted: 03/16/2018] [Indexed: 11/26/2022]
Abstract
The HIV-1 core consists of capsid proteins (CA) surrounding viral genomic RNA. After virus-cell fusion, the core enters the cytoplasm and the capsid shell is lost through uncoating. CA loss precedes nuclear import and HIV integration into the host genome, but the timing and location of uncoating remain unclear. By visualizing single HIV-1 infection, we find that CA is required for core docking at the nuclear envelope (NE), whereas early uncoating in the cytoplasm promotes proteasomal degradation of viral complexes. Only docked cores exhibiting accelerated loss of CA at the NE enter the nucleus. Interestingly, a CA mutation (N74D) altering virus engagement of host factors involved in nuclear transport does not alter the uncoating site at the NE but reduces the nuclear penetration depth. Thus, CA protects HIV-1 complexes from degradation, mediates docking at the nuclear pore before uncoating, and determines the depth of nuclear penetration en route to integration.
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Affiliation(s)
| | - Gregory B Melikyan
- Department of Pediatrics, Emory University, Atlanta, GA 30322, USA; Children's Healthcare of Atlanta, Atlanta, GA 30322, USA.
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146
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Achuthan V, Perreira JM, Sowd GA, Puray-Chavez M, McDougall WM, Paulucci-Holthauzen A, Wu X, Fadel HJ, Poeschla EM, Multani AS, Hughes SH, Sarafianos SG, Brass AL, Engelman AN. Capsid-CPSF6 Interaction Licenses Nuclear HIV-1 Trafficking to Sites of Viral DNA Integration. Cell Host Microbe 2018; 24:392-404.e8. [PMID: 30173955 PMCID: PMC6368089 DOI: 10.1016/j.chom.2018.08.002] [Citation(s) in RCA: 118] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Revised: 06/22/2018] [Accepted: 08/01/2018] [Indexed: 10/28/2022]
Abstract
HIV-1 integration into the host genome favors actively transcribed genes. Prior work indicated that the nuclear periphery provides the architectural basis for integration site selection, with viral capsid-binding host cofactor CPSF6 and viral integrase-binding cofactor LEDGF/p75 contributing to selection of individual sites. Here, by investigating the early phase of infection, we determine that HIV-1 traffics throughout the nucleus for integration. CPSF6-capsid interactions allow the virus to bypass peripheral heterochromatin and penetrate the nuclear structure for integration. Loss of interaction with CPSF6 dramatically alters virus localization toward the nuclear periphery and integration into transcriptionally repressed lamina-associated heterochromatin, while loss of LEDGF/p75 does not significantly affect intranuclear HIV-1 localization. Thus, CPSF6 serves as a master regulator of HIV-1 intranuclear localization by trafficking viral preintegration complexes away from heterochromatin at the periphery toward gene-dense chromosomal regions within the nuclear interior.
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Affiliation(s)
- Vasudevan Achuthan
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, MA 02215, USA; Department of Medicine, Harvard Medical School, Boston, MA 02115, USA
| | - Jill M Perreira
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Gregory A Sowd
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, MA 02215, USA; Department of Medicine, Harvard Medical School, Boston, MA 02115, USA
| | - Maritza Puray-Chavez
- Department of Molecular Microbiology & Immunology, University of Missouri School of Medicine, Columbia, MO 65212, USA
| | - William M McDougall
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | | | - Xiaolin Wu
- Leidos Biomedical Research, Inc., Frederick, MD 21702, USA
| | - Hind J Fadel
- Division of Molecular Medicine, Mayo Clinic, Rochester, MN 55905, USA
| | - Eric M Poeschla
- Division of Infectious Diseases, University of Colorado Denver School of Medicine, Aurora, CO 80045, USA
| | - Asha S Multani
- Department of Genetics, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Stephen H Hughes
- HIV Dynamics and Replication Program, National Cancer Institute, Frederick, MD 21702, USA
| | - Stefan G Sarafianos
- Department of Molecular Microbiology & Immunology, University of Missouri School of Medicine, Columbia, MO 65212, USA
| | - Abraham L Brass
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, MA 01655, USA; Gastroenterology Division, Department of Medicine, University of Massachusetts Medical School, Worcester, MA 01655, 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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147
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Nup153 Unlocks the Nuclear Pore Complex for HIV-1 Nuclear Translocation in Nondividing Cells. J Virol 2018; 92:JVI.00648-18. [PMID: 29997211 DOI: 10.1128/jvi.00648-18] [Citation(s) in RCA: 68] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Accepted: 06/20/2018] [Indexed: 12/27/2022] Open
Abstract
Human immunodeficiency virus type 1 (HIV-1) displays the unique ability to infect nondividing cells. The capsid of HIV-1 is the viral determinant for viral nuclear import. To understand the cellular factors involved in the ability of HIV-1 to infect nondividing cells, we sought to find capsid mutations that allow the virus to infect dividing but not nondividing cells. Because the interaction of capsid with the nucleoporin protein 153 (Nup153) is important for nuclear import of HIV-1, we solved new crystal structures of hexameric HIV-1 capsid in complex with a Nup153-derived peptide containing a phenylalanine-glycine repeat (FG repeat), which we used to guide structure-based mutagenesis of the capsid-binding interface. HIV-1 viruses with mutations in these capsid residues were tested for their ability to infect dividing and nondividing cells. HIV-1 viruses with capsid N57 substitutions infected dividing but not nondividing cells. Interestingly, HIV-1 viruses with N57 mutations underwent reverse transcription but not nuclear translocation. The mutant capsids also lost the ability to interact with Nup153 and CPSF6. The use of small molecules PF74 and BI-2 prevented the interaction of FG-containing nucleoporins (Nups), such as Nup153, with the HIV-1 core. Analysis of integration sites in HIV-1 viruses with N57 mutations revealed diminished integration into transcriptionally active genes in a manner resembling that of HIV-1 in CPSF6 knockout cells or that of HIV-1-N74D. The integration pattern of the N57 mutant HIV-1 can be explained by loss of capsid interaction with CPSF6, whereas capsid interaction with Nup153 is required for HIV-1 to infect nondividing cells. Additionally, the observed viral integration profiles suggested that integration site selection is a multiparameter process that depends upon nuclear factors and the state of the cellular chromatin.IMPORTANCE One of the key advantages that distinguish lentiviruses, such as HIV-1, from all other retroviruses is its ability to infect nondividing cells. Interaction of the HIV-1 capsid with Nup153 and CPSF6 is important for nuclear entry and integration; however, the contribution of each of these proteins to nuclear import and integration is not clear. Using genetics, we demonstrated that these proteins contribute to different processes: Nup153 is essential for the HIV-1 nuclear import in nondividing cells, and CPSF6 is important for HIV-1 integration. In addition, nuclear factors such as CPSF6 and the state of the chromatin are known to be important for integration site selection; nevertheless, the preferential determinant influencing integration site selection is not known. This work demonstrates that integration site selection is a multiparameter process that depends upon nuclear factors and the state of the cellular chromatin.
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148
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Kane M, Rebensburg SV, Takata MA, Zang TM, Yamashita M, Kvaratskhelia M, Bieniasz PD. Nuclear pore heterogeneity influences HIV-1 infection and the antiviral activity of MX2. eLife 2018; 7:e35738. [PMID: 30084827 PMCID: PMC6101944 DOI: 10.7554/elife.35738] [Citation(s) in RCA: 89] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Accepted: 08/06/2018] [Indexed: 12/14/2022] Open
Abstract
HIV-1 accesses the nuclear DNA of interphase cells via a poorly defined process involving functional interactions between the capsid protein (CA) and nucleoporins (Nups). Here, we show that HIV-1 CA can bind multiple Nups, and that both natural and manipulated variation in Nup levels impacts HIV-1 infection in a manner that is strikingly dependent on cell-type, cell-cycle, and cyclophilin A (CypA). We also show that Nups mediate the function of the antiviral protein MX2, and that MX2 can variably inhibit non-viral NLS function. Remarkably, both enhancing and inhibiting effects of cyclophilin A and MX2 on various HIV-1 CA mutants could be induced or abolished by manipulating levels of the Nup93 subcomplex, the Nup62 subcomplex, NUP88, NUP214, RANBP2, or NUP153. Our findings suggest that several Nup-dependent 'pathways' are variably exploited by HIV-1 to target host DNA in a cell-type, cell-cycle, CypA and CA-sequence dependent manner, and are differentially inhibited by MX2.
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Affiliation(s)
- Melissa Kane
- Laboratory of RetrovirologyThe Rockefeller UniversityNew YorkUnited States
| | - Stephanie V Rebensburg
- Division of Infectious DiseasesUniversity of Colorado School of MedicineAuroraUnited States
| | - Matthew A Takata
- Laboratory of RetrovirologyThe Rockefeller UniversityNew YorkUnited States
| | - Trinity M Zang
- Laboratory of RetrovirologyThe Rockefeller UniversityNew YorkUnited States
- Howard Hughes Medical InstituteNew YorkUnited States
| | | | - Mamuka Kvaratskhelia
- Division of Infectious DiseasesUniversity of Colorado School of MedicineAuroraUnited States
| | - Paul D Bieniasz
- Laboratory of RetrovirologyThe Rockefeller UniversityNew YorkUnited States
- Howard Hughes Medical InstituteNew YorkUnited States
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149
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Abstract
Recent studies show that human immunodeficiency virus type 1 (HIV-1) can utilize microtubules and their associated proteins to complete key postfusion steps during infection. These include associating with both dynein and kinesin motors, as well as proteins, which enhance infection by altering microtubule dynamics during infection. In this article, we will discuss findings on how dynein and kinesin motors, as well as other microtubule-associated proteins, influence HIV-1 trafficking, viral core uncoating, and nuclear import of the viral ribonucleoprotein (RNP).
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150
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Abstract
Human immunodeficiency virus (HIV) is one of the most studied of all human pathogens. One strain-HIV-1 group M-is responsible for a global pandemic that has infected >60 million people and killed >20 million. Understanding the stages of HIV infection has led to highly effective therapeutics in the form of antiviral drugs that target the viral enzymes reverse transcriptase, integrase, and protease as well as biotechnological developments in the form of retroviral and lentiviral vectors for the transduction of cells in tissue culture and, potentially, gene therapy. However, despite considerable research focus in this area, there is much we still do not understand about the HIV replicative cycle, particularly the first steps that are crucial to establishing a productive infection. One especially enigmatic player has been the HIV capsid. In this review, we discuss three aspects of the HIV capsid: its function as a structural shell, its role in mediating host interactions, and its vulnerability to antiviral activity.
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Affiliation(s)
- Leo C James
- Medical Research Council Laboratory of Molecular Biology, Cambridge CB2 0QH, United Kingdom;
| | - David A Jacques
- EMBL Australia Node in Single Molecule Science and ARC Centre of Excellence in Advanced Molecular Imaging, School of Medical Sciences, University of New South Wales Sydney, Randwick NSW 2031, Australia;
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