1
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Proulx J, Borgmann K, Park IW. Post-translational modifications inducing proteasomal degradation to counter HIV-1 infection. Virus Res 2020; 289:198142. [PMID: 32882242 DOI: 10.1016/j.virusres.2020.198142] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2020] [Revised: 08/20/2020] [Accepted: 08/21/2020] [Indexed: 12/14/2022]
Abstract
Post-translational modifications (PTMs) are integral to regulating a wide variety of cellular processes in eukaryotic cells, such as regulation of protein stability, alteration of celluar location, protein activity modulation, and regulation of protein interactions. HIV-1, like other eukaryotic viruses, and its infected host exploit the proteasomal degradation system for their respective proliferation and survival, using various PTMs, including but not limited to ubiquitination, SUMOylation, NEDDylation, interferon-stimulated gene (ISG)ylation. Essentially all viral proteins within the virions -- and in the HIV-1-infected cells -- interact with their cellular counterparts for this degradation, utilizing ubiquitin (Ub), and the Ub-like (Ubl) modifiers less frequently, to eliminate the involved proteins throughout the virus life cycle, from the entry step to release of the assembled virus particles. Such interplay is pivotal for, on the one hand, the cell to restrict proliferation of the infecting virus, and on the other, for molecular counteraction by the virus to overcome this cellular protein-imposed restriction. Recent reports indicate that not only viral/cellular proteins but also viral/viral protein interactions play vital roles in regulating viral protein stability. We hence give an overview of the molecular processes of PTMs involved in proteasomal degradation of the viral and cellular proteins, and the viral/viral and viral/cellular protein interplay in restriction and competition for HIV-1 vs. host cell survival. Insights in this realm could open new avenues for developing therapeutics against HIV-1 via targeting specific steps of the proteasome degradation pathway during the HIV-1 life cycle.
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Affiliation(s)
- Jessica Proulx
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, TX, 76107, United States
| | - Kathleen Borgmann
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, TX, 76107, United States
| | - In-Woo Park
- Microbiology, Immunology, and Genetics, University of North Texas Health Science Center, Fort Worth, TX, 76107, United States.
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2
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Shimagaki K, Koga R, Fujino H, Ahagon A, Tateishi H, Otsuka M, Yamaguchi Y, Fujita M. The stability of HIV-2 Vpx and Vpr proteins is regulated by the presence or absence of zinc-binding sites and poly-proline motifs with distinct roles. J Gen Virol 2020; 101:997-1007. [PMID: 32553018 DOI: 10.1099/jgv.0.001456] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The Vpx and Vpr proteins of human immunodeficiency virus type 2 (HIV-2) are important for virus replication. Although these proteins are homologous, Vpx is expressed at much higher levels than Vpr. Previous studies demonstrated that this difference results from the presence of an HHCC zinc-binding site in Vpx that is absent in Vpr. Vpx has another unique region, a poly-proline motif (PPM) of seven consecutive prolines at the C-terminus. Using PPM point mutants of Vpx, this study demonstrated that these seven consecutive prolines are critical for suppressing proteasome degradation of Vpx in the absence of Gag. Both the PPM and the zinc-binding site stabilize Vpx but do so via different mechanisms. PPM and zinc-binding site mutants overexpressed in Escherichia coli aggregated readily, indicating that these motifs normally prevent exposure of the hydrophobic region outside the structure. Furthermore, introduction of the zinc-binding site and the PPM into Vpr increased the level of Vpr expression so that it was as high as that of Vpx. Intriguingly, HIV-2 has evolved to express Vpx at high levels and Vpr at low levels based on the presence and absence of these two motifs with distinct roles.
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Affiliation(s)
- Kazunori Shimagaki
- Medicinal and Biological Chemistry Science Farm Joint Research Laboratory, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
| | - Ryoko Koga
- Medicinal and Biological Chemistry Science Farm Joint Research Laboratory, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
| | - Haruna Fujino
- Medicinal and Biological Chemistry Science Farm Joint Research Laboratory, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
| | - Ami Ahagon
- Medicinal and Biological Chemistry Science Farm Joint Research Laboratory, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
| | - Hiroshi Tateishi
- Medicinal and Biological Chemistry Science Farm Joint Research Laboratory, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
| | - Masami Otsuka
- Science Farm Ltd, Kumamoto, Japan.,Medicinal and Biological Chemistry Science Farm Joint Research Laboratory, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
| | | | - Mikako Fujita
- Medicinal and Biological Chemistry Science Farm Joint Research Laboratory, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
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3
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Miyakawa K, Matsunaga S, Yokoyama M, Nomaguchi M, Kimura Y, Nishi M, Kimura H, Sato H, Hirano H, Tamura T, Akari H, Miura T, Adachi A, Sawasaki T, Yamamoto N, Ryo A. PIM kinases facilitate lentiviral evasion from SAMHD1 restriction via Vpx phosphorylation. Nat Commun 2019; 10:1844. [PMID: 31015445 PMCID: PMC6479052 DOI: 10.1038/s41467-019-09867-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Accepted: 04/04/2019] [Indexed: 12/22/2022] Open
Abstract
Lentiviruses have evolved to acquire an auxiliary protein Vpx to counteract the intrinsic host restriction factor SAMHD1. Although Vpx is phosphorylated, it remains unclear whether such phosphorylation indeed regulates its activity toward SAMHD1. Here we identify the PIM family of serine/threonine protein kinases as the factors responsible for the phosphorylation of Vpx and the promotion of Vpx-mediated SAMHD1 counteraction. Integrated proteomics and subsequent functional analysis reveal that PIM family kinases, PIM1 and PIM3, phosphorylate HIV-2 Vpx at Ser13 and stabilize the interaction of Vpx with SAMHD1 thereby promoting ubiquitin-mediated proteolysis of SAMHD1. Inhibition of the PIM kinases promotes the antiviral activity of SAMHD1, ultimately reducing viral replication. Our results highlight a new mode of virus–host cell interaction in which host PIM kinases facilitate promotion of viral infectivity by counteracting the host antiviral system, and suggest a novel therapeutic strategy involving restoration of SAMHD1-mediated antiviral response. The accessory lentiviral protein X (Vpx) of the SIVsmm/mac and HIV-2 lineage targets the host-restriction factor SAMHD1 for proteasomal degradation. Here, the authors show that host PIM kinase-mediated phosphorylation of Vpx stabilizes its interaction with SAMHD1, suggesting PIM as potential antiviral targets.
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Affiliation(s)
- Kei Miyakawa
- Department of Microbiology, Yokohama City University School of Medicine, Kanagawa, 236-0004, Japan
| | - Satoko Matsunaga
- Department of Microbiology, Yokohama City University School of Medicine, Kanagawa, 236-0004, Japan
| | - Masaru Yokoyama
- Pathogen Genomics Center, National Institute of Infectious Diseases, Musashi Murayama, Tokyo, 208-0011, Japan
| | - Masako Nomaguchi
- Department of Microbiology, Tokushima University Graduate School of Medical Science, Tokushima, 770-8503, Japan
| | - Yayoi Kimura
- Advanced Medical Research Center, Yokohama City University, Kanagawa, 236-0004, Japan
| | - Mayuko Nishi
- Department of Microbiology, Yokohama City University School of Medicine, Kanagawa, 236-0004, Japan
| | - Hirokazu Kimura
- School of Medical Technology, Faculty of Health Sciences, Gunma Paz University, Gunma, 370-0006, Japan
| | - Hironori Sato
- Pathogen Genomics Center, National Institute of Infectious Diseases, Musashi Murayama, Tokyo, 208-0011, Japan
| | - Hisashi Hirano
- Advanced Medical Research Center, Yokohama City University, Kanagawa, 236-0004, Japan
| | - Tomohiko Tamura
- Department of Immunology, Yokohama City University School of Medicine, Kanagawa, 236-0004, Japan
| | - Hirofumi Akari
- Laboratory of Infectious Disease Model, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, 606-8507, Japan.,Center for Human Evolution Modeling Research, Primate Research Institute, Kyoto University, Aichi, 484-8506, Japan
| | - Tomoyuki Miura
- Center for Human Evolution Modeling Research, Primate Research Institute, Kyoto University, Aichi, 484-8506, Japan
| | - Akio Adachi
- Department of Microbiology, Tokushima University Graduate School of Medical Science, Tokushima, 770-8503, Japan.,Department of Microbiology, Kansai Medical University, Osaka, 573-1010, Japan
| | | | - Naoki Yamamoto
- National Institute of Infectious Diseases, Tokyo, 162-8640, Japan.,Tokyo Medical and Dental University, Tokyo, 113-8519, Japan
| | - Akihide Ryo
- Department of Microbiology, Yokohama City University School of Medicine, Kanagawa, 236-0004, Japan. .,Advanced Medical Research Center, Yokohama City University, Kanagawa, 236-0004, Japan.
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4
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Zhang Y, Ozono S, Yao W, Tobiume M, Yamaoka S, Kishigami S, Fujita H, Tokunaga K. CRISPR-mediated activation of endogenous BST-2/tetherin expression inhibits wild-type HIV-1 production. Sci Rep 2019; 9:3134. [PMID: 30816279 PMCID: PMC6395588 DOI: 10.1038/s41598-019-40003-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Accepted: 02/07/2019] [Indexed: 12/21/2022] Open
Abstract
The CRISPR technology not only can knock out target genes by using the RNA-guided Cas9 nuclease but also can activate their expression when a nuclease-deficient Cas9 (dCas9) is employed. Using the latter function, we here show the effect of the CRISPR-mediated pinpoint activation of endogenous expression of BST-2 (also known as tetherin), a virus restriction factor with a broad antiviral spectrum. Single-guide RNA (sgRNA) sequences targeting the BST-2 promoter were selected by promoter assays. Potential sgRNAs and dCas9 fused to the VP64 transactivation domain, along with an accessory transcriptional activator complex, were introduced into cells by lentiviral transduction. Increased expression of BST-2 mRNA in transduced cells was confirmed by real-time RT-PCR. Cells in which BST-2 expression was highly enhanced showed the effective inhibition of HIV-1 production and replication even in the presence of the viral antagonist Vpu against BST-2. These findings confirm that the physiological stoichiometry between host restriction factors and viral antagonists may determine the outcome of the battle with viruses.
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Affiliation(s)
- Yanzhao Zhang
- Department of Pathology, National Institute of Infectious Diseases, Tokyo, 162-8640, Japan
| | - Seiya Ozono
- Department of Pathology, National Institute of Infectious Diseases, Tokyo, 162-8640, Japan
- Faculty of Life and Environmental Sciences, University of Yamanashi, Yamanashi, 400-8510, Japan
| | - Weitong Yao
- Department of Pathology, National Institute of Infectious Diseases, Tokyo, 162-8640, Japan
- Department of Molecular Virology, Tokyo Medical and Dental University, Tokyo, 113-8519, Japan
| | - Minoru Tobiume
- Department of Pathology, National Institute of Infectious Diseases, Tokyo, 162-8640, Japan
| | - Shoji Yamaoka
- Department of Molecular Virology, Tokyo Medical and Dental University, Tokyo, 113-8519, Japan
| | - Satoshi Kishigami
- Faculty of Life and Environmental Sciences, University of Yamanashi, Yamanashi, 400-8510, Japan
| | - Hideaki Fujita
- Faculty of Pharmaceutical Sciences, Nagasaki International University, Nagasaki, 859-3298, Japan
| | - Kenzo Tokunaga
- Department of Pathology, National Institute of Infectious Diseases, Tokyo, 162-8640, Japan.
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5
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Chougui G, Margottin-Goguet F. HUSH, a Link Between Intrinsic Immunity and HIV Latency. Front Microbiol 2019; 10:224. [PMID: 30809215 PMCID: PMC6379475 DOI: 10.3389/fmicb.2019.00224] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Accepted: 01/28/2019] [Indexed: 12/29/2022] Open
Abstract
A prominent obstacle to HIV eradication in seropositive individuals is the viral persistence in latent reservoir cells, which constitute an HIV sanctuary out of reach of highly active antiretroviral therapies. Thus, the study of molecular mechanisms governing latency is a very active field that aims at providing solutions to face the reservoirs issue. Since the past 15 years, another major field in HIV biology focused on the discovery and study of restriction factors that shape intrinsic immunity, while engaging in a molecular battle against HIV. Some of these restrictions factors act at early stages of the virus life cycle, alike SAMHD1 antagonized by the viral protein Vpx, while others are late actors. Until recently, no such factor was identified in the nucleus and found active at the level of provirus expression, a crucial step where latency may take place. Today, two studies highlight Human Silencing Hub (HUSH) as a potential restriction factor that controls viral expression and is antagonized by Vpx. This Review discusses HUSH restriction in the light of the actual knowledge of intrinsic immunity and HIV latency.
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Affiliation(s)
- Ghina Chougui
- Inserm, U1016, Institut Cochin, Paris, France.,CNRS, UMR8104, Paris, France.,Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Florence Margottin-Goguet
- Inserm, U1016, Institut Cochin, Paris, France.,CNRS, UMR8104, Paris, France.,Université Paris Descartes, Sorbonne Paris Cité, Paris, France
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6
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Koga R, Yamamoto M, Ciftci HI, Otsuka M, Fujita M. Introduction of H2C2-type zinc-binding residues into HIV-2 Vpr increases its expression level. FEBS Open Bio 2018; 8:146-153. [PMID: 29321964 PMCID: PMC5757179 DOI: 10.1002/2211-5463.12358] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Revised: 11/11/2017] [Accepted: 11/22/2017] [Indexed: 12/21/2022] Open
Abstract
Human immunodeficiency virus type 2 has two structurally similar proteins, Vpx and Vpr. Vpx degrades the host anti-viral protein SAMHD1 and is expressed at high levels, while Vpr is responsible for cell cycle arrest and is expressed at much lower levels. We constructed a Vpr mutant with a high level of expression by replacing the amino acids HHCR/HHCH with a putative H2C2-type zinc-binding site that is carried by Vpx. Our finding suggests that during the evolution of Vpr and Vpx, zinc-binding likely became a mechanism for regulating their expression levels.
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Affiliation(s)
- Ryoko Koga
- Department of Bioorganic Medicinal Chemistry Faculty of Life Sciences Kumamoto University Japan
| | - Minami Yamamoto
- Department of Bioorganic Medicinal Chemistry Faculty of Life Sciences Kumamoto University Japan
| | - Halil Ibrahim Ciftci
- Department of Bioorganic Medicinal Chemistry Faculty of Life Sciences Kumamoto University Japan
| | - Masami Otsuka
- Department of Bioorganic Medicinal Chemistry Faculty of Life Sciences Kumamoto University Japan
| | - Mikako Fujita
- Research Institute for Drug Discovery School of Pharmacy Kumamoto University Japan
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7
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Miyazaki Y, Miyake A, Doi N, Koma T, Uchiyama T, Adachi A, Nomaguchi M. Comparison of Biochemical Properties of HIV-1 and HIV-2 Capsid Proteins. Front Microbiol 2017; 8:1082. [PMID: 28659897 PMCID: PMC5469281 DOI: 10.3389/fmicb.2017.01082] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Accepted: 05/29/2017] [Indexed: 01/08/2023] Open
Abstract
Timely disassembly of viral core composed of self-assembled capsid (CA) in infected host cells is crucial for retroviral replication. Extensive in vitro studies to date on the self-assembly/disassembly mechanism of human immunodeficiency virus type 1 (HIV-1) CA have revealed its core structure and amino acid residues essential for CA–CA intermolecular interaction. However, little is known about in vitro properties of HIV-2 CA. In this study, we comparatively analyzed the polymerization properties of bacterially expressed HIV-1 and HIV-2 CA proteins. Interestingly, a much higher concentration of NaCl was required for HIV-2 CA to self-assemble than that for HIV-1 CA, but once the polymerization started, the reaction proceeded more rapidly than that observed for HIV-1 CA. Analysis of a chimeric protein revealed that N-terminal domain (NTD) is responsible for this unique property of HIV-2 CA. To further study the molecular basis for different in vitro properties of HIV-1 and HIV-2 CA proteins, we determined thermal stabilities of HIV-1 and HIV-2 CA NTD proteins at several NaCl concentrations by fluorescent-based thermal shift assays. Experimental data obtained showed that HIV-2 CA NTD was structurally more stable than HIV-1 CA NTD. Taken together, our results imply that distinct in vitro polymerization abilities of the two CA proteins are related to their structural instability/stability, which is one of the decisive factors for viral replication potential. In addition, our assay system described here may be potentially useful for searching for anti-CA antivirals against HIV-1 and HIV-2.
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Affiliation(s)
- Yasuyuki Miyazaki
- Department of Microbiology and Cell Biology, Tokyo Metropolitan Institute of Medical ScienceTokyo, Japan
| | - Ariko Miyake
- Laboratory of Molecular Immunology and Infectious Disease, Joint Faculty of Veterinary Medicine, Yamaguchi UniversityYamaguchi, Japan
| | - Noya Doi
- Department of Microbiology, Tokushima University Graduate School of Medical SciencesTokushima, Japan
| | - Takaaki Koma
- Department of Microbiology, Tokushima University Graduate School of Medical SciencesTokushima, Japan
| | - Tsuneo Uchiyama
- Department of Microbiology, Tokushima University Graduate School of Medical SciencesTokushima, Japan
| | - Akio Adachi
- Department of Microbiology, Tokushima University Graduate School of Medical SciencesTokushima, Japan
| | - Masako Nomaguchi
- Department of Microbiology, Tokushima University Graduate School of Medical SciencesTokushima, Japan
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8
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Yamamoto M, Koga R, Fujino H, Shimagaki K, Ciftci HI, Kamo M, Tateishi H, Otsuka M, Fujita M. Zinc-binding site of human immunodeficiency virus 2 Vpx prevents instability and dysfunction of the protein. J Gen Virol 2017; 98:275-283. [DOI: 10.1099/jgv.0.000701] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Minami Yamamoto
- Department of Bioorganic Medicinal Chemistry, Faculty of Life Sciences, Kumamoto University, 5-1 Oe-honmachi, Chuo-ku, Kumamoto 862-0973, Japan
| | - Ryoko Koga
- Department of Bioorganic Medicinal Chemistry, Faculty of Life Sciences, Kumamoto University, 5-1 Oe-honmachi, Chuo-ku, Kumamoto 862-0973, Japan
| | - Haruna Fujino
- Department of Bioorganic Medicinal Chemistry, Faculty of Life Sciences, Kumamoto University, 5-1 Oe-honmachi, Chuo-ku, Kumamoto 862-0973, Japan
| | - Kazunori Shimagaki
- Department of Bioorganic Medicinal Chemistry, Faculty of Life Sciences, Kumamoto University, 5-1 Oe-honmachi, Chuo-ku, Kumamoto 862-0973, Japan
| | - Halil Ibrahim Ciftci
- Department of Bioorganic Medicinal Chemistry, Faculty of Life Sciences, Kumamoto University, 5-1 Oe-honmachi, Chuo-ku, Kumamoto 862-0973, Japan
| | - Masahiro Kamo
- Department of Bioorganic Medicinal Chemistry, Faculty of Life Sciences, Kumamoto University, 5-1 Oe-honmachi, Chuo-ku, Kumamoto 862-0973, Japan
| | - Hiroshi Tateishi
- Department of Bioorganic Medicinal Chemistry, Faculty of Life Sciences, Kumamoto University, 5-1 Oe-honmachi, Chuo-ku, Kumamoto 862-0973, Japan
| | - Masami Otsuka
- Department of Bioorganic Medicinal Chemistry, Faculty of Life Sciences, Kumamoto University, 5-1 Oe-honmachi, Chuo-ku, Kumamoto 862-0973, Japan
| | - Mikako Fujita
- Research Institute for Drug Discovery, School of Pharmacy, Kumamoto University, 5-1 Oe-honmachi, Chuo-ku, Kumamoto 862-0973, Japan
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9
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Natural Single-Nucleotide Variations in the HIV-1 Genomic SA1prox Region Can Alter Viral Replication Ability by Regulating Vif Expression Levels. J Virol 2016; 90:4563-4578. [PMID: 26912631 DOI: 10.1128/jvi.02939-15] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2015] [Accepted: 02/15/2016] [Indexed: 12/23/2022] Open
Abstract
UNLABELLED We previously found that natural single-nucleotide variations located within a proximal region of splicing acceptor 1 (SA1prox) in the HIV-1 genome could alter the viral replication potential and mRNA expression pattern, especially the vif mRNA level. Here, we studied the virological and molecular basis of nucleotide sequence variations in SA1prox for alterations of viral replication ability. Consistent with our previous findings, variant clones indeed expressed Vif at different levels and grew distinctively in cells with various APOBEC3G expression levels. Similar effects were observed for natural variations found in HIV-2 SA1prox, suggesting the importance of the SA1prox sequence. To define nucleotides critical for the regulation of HIV-1 Vif expression, effects of natural SA1prox variations newly found in the HIV Sequence Compendium database on vif mRNA/Vif protein levels were examined. Seven out of nine variations were found to produce Vif at lower, higher, or more excessive levels than wild-type NL4-3. Combination experiments of variations giving distinct Vif levels suggested that the variations mutually affected vif transcript production. While low and high producers of Vif grew in an APOBEC3G-dependent manner, excessive expressers always showed an impeded growth phenotype due to defects in single-cycle infectivity and/or virion production levels. The phenotype of excessive expressers was not due primarily to inadequate expression of Tat or Rev, although SA1prox variations altered the overall HIV-1 mRNA expression pattern. Collectively, our results demonstrate that HIV SA1prox regulates Vif expression levels and suggest a relationship between SA1prox and viral adaptation/evolution given that variations occurred naturally. IMPORTANCE While human cells possess restriction factors to inhibit HIV-1 replication, HIV-1 encodes antagonists to overcome these barriers. Conflicts between host restriction factors and viral counterparts are critical driving forces behind mutual evolution. The interplay of cellular APOBEC3G and viral Vif proteins is a typical example. Here, we demonstrate that naturally occurring single-nucleotide variations in the proximal region of splicing acceptor 1 (SA1prox) of the HIV-1 genome frequently alter Vif expression levels, thereby modulating viral replication potential in cells with various ABOBEC3G levels. The results of the present study reveal a previously unidentified and important way for HIV-1 to compete with APOBEC3G restriction by regulating its Vif expression levels. We propose that SA1prox plays a regulatory role in Vif counteraction against APOBEC3G in order to contribute to HIV-1 replication and evolution, and this may be applicable to other primate lentiviruses.
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10
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SUN2 Overexpression Deforms Nuclear Shape and Inhibits HIV. J Virol 2016; 90:4199-4214. [PMID: 26865710 DOI: 10.1128/jvi.03202-15] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Accepted: 02/03/2016] [Indexed: 12/25/2022] Open
Abstract
UNLABELLED In a previous screen of putative interferon-stimulated genes, SUN2 was shown to inhibit HIV-1 infection in an uncharacterized manner. SUN2 is an inner nuclear membrane protein belonging to the linker of nucleoskeleton and cytoskeleton complex. We have analyzed here the role of SUN2 in HIV infection. We report that in contrast to what was initially thought, SUN2 is not induced by type I interferon, and that SUN2 silencing does not modulate HIV infection. However, SUN2 overexpression in cell lines and in primary monocyte-derived dendritic cells inhibits the replication of HIV but not murine leukemia virus or chikungunya virus. We identified HIV-1 and HIV-2 strains that are unaffected by SUN2, suggesting that the effect is specific to particular viral components or cofactors. Intriguingly, SUN2 overexpression induces a multilobular flower-like nuclear shape that does not impact cell viability and is similar to that of cells isolated from patients with HTLV-I-associated adult T-cell leukemia or with progeria. Nuclear shape changes and HIV inhibition both mapped to the nucleoplasmic domain of SUN2 that interacts with the nuclear lamina. This block to HIV replication occurs between reverse transcription and nuclear entry, and passaging experiments selected for a single-amino-acid change in capsid (CA) that leads to resistance to overexpressed SUN2. Furthermore, using chemical inhibition or silencing of cyclophilin A (CypA), as well as CA mutant viruses, we implicated CypA in the SUN2-imposed block to HIV infection. Our results demonstrate that SUN2 overexpression perturbs both nuclear shape and early events of HIV infection. IMPORTANCE Cells encode proteins that interfere with viral replication, a number of which have been identified in overexpression screens. SUN2 is a nuclear membrane protein that was shown to inhibit HIV infection in such a screen, but how it blocked HIV infection was not known. We show that SUN2 overexpression blocks the infection of certain strains of HIV before nuclear entry. Mutation of the viral capsid protein yielded SUN2-resistant HIV. Additionally, the inhibition of HIV infection by SUN2 involves cyclophilin A, a protein that binds the HIV capsid and directs subsequent steps of infection. We also found that SUN2 overexpression substantially changes the shape of the cell's nucleus, resulting in many flower-like nuclei. Both HIV inhibition and deformation of nuclear shape required the domain of SUN2 that interacts with the nuclear lamina. Our results demonstrate that SUN2 interferes with HIV infection and highlight novel links between nuclear shape and viral infection.
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11
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Mutational analysis of HIV-2 Vpx shows that proline residue 109 in the poly-proline motif regulates degradation of SAMHD1. FEBS Lett 2015; 589:1505-14. [DOI: 10.1016/j.febslet.2015.04.038] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2015] [Revised: 04/13/2015] [Accepted: 04/21/2015] [Indexed: 11/22/2022]
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12
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Chauveau L, Puigdomenech I, Ayinde D, Roesch F, Porrot F, Bruni D, Visseaux B, Descamps D, Schwartz O. HIV-2 infects resting CD4+ T cells but not monocyte-derived dendritic cells. Retrovirology 2015; 12:2. [PMID: 25582927 PMCID: PMC4307230 DOI: 10.1186/s12977-014-0131-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Accepted: 12/17/2014] [Indexed: 12/30/2022] Open
Abstract
Background Human Immunodeficiency Virus-type 2 (HIV-2) encodes Vpx that degrades SAMHD1, a cellular restriction factor active in non-dividing cells. HIV-2 replicates in lymphocytes but the susceptibility of monocyte-derived dendritic cells (MDDCs) to in vitro infection remains partly characterized. Results Here, we investigated HIV-2 replication in primary CD4+ T lymphocytes, both activated and non-activated, as well as in MDDCs. We focused on the requirement of Vpx for productive HIV-2 infection, using the reference HIV-2 ROD strain, the proviral clone GL-AN, as well as two primary HIV-2 isolates. All HIV-2 strains tested replicated in activated CD4+ T cells. Unstimulated CD4+ T cells were not productively infected by HIV-2, but viral replication was triggered upon lymphocyte activation in a Vpx-dependent manner. In contrast, MDDCs were poorly infected when exposed to HIV-2. HIV-2 particles did not potently fuse with MDDCs and did not lead to efficient viral DNA synthesis, even in the presence of Vpx. Moreover, the HIV-2 strains tested were not efficiently sensed by MDDCs, as evidenced by a lack of MxA induction upon viral exposure. Virion pseudotyping with VSV-G rescued fusion, productive infection and HIV-2 sensing by MDDCs. Conclusion Vpx allows the non-productive infection of resting CD4+ T cells, but does not confer HIV-2 with the ability to efficiently infect MDDCs. In these cells, an entry defect prevents viral fusion and reverse transcription independently of SAMHD1. We propose that HIV-2, like HIV-1, does not productively infect MDDCs, possibly to avoid triggering an immune response mediated by these cells. Electronic supplementary material The online version of this article (doi:10.1186/s12977-014-0131-7) contains supplementary material, which is available to authorized users.
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13
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Schaller T, Bauby H, Hué S, Malim MH, Goujon C. New insights into an X-traordinary viral protein. Front Microbiol 2014; 5:126. [PMID: 24782834 PMCID: PMC3986551 DOI: 10.3389/fmicb.2014.00126] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2014] [Accepted: 03/11/2014] [Indexed: 11/13/2022] Open
Abstract
Vpx is a protein encoded by members of the HIV-2/SIVsmm and SIVrcm/SIVmnd-2 lineages of primate lentiviruses, and is packaged into viral particles. Vpx plays a critical role during the early steps of the viral life cycle and has been shown to counteract SAMHD1, a restriction factor in myeloid and resting T cells. However, it is becoming evident that Vpx is a multifunctional protein in that SAMHD1 antagonism is likely not its sole role. This review summarizes the current knowledge on this X-traordinary protein.
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Affiliation(s)
- Torsten Schaller
- Department of Infectious Diseases, King's College London London, UK
| | - Hélène Bauby
- Department of Infectious Diseases, King's College London London, UK
| | - Stéphane Hué
- Department of Infection, Division of Infection and Immunity, Centre for Medical Molecular Virology, University College London London, UK
| | - Michael H Malim
- Department of Infectious Diseases, King's College London London, UK
| | - Caroline Goujon
- Department of Infectious Diseases, King's College London London, UK
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Cheng X, Ratner L. HIV-2 Vpx protein interacts with interferon regulatory factor 5 (IRF5) and inhibits its function. J Biol Chem 2014; 289:9146-57. [PMID: 24532789 DOI: 10.1074/jbc.m113.534321] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Interferon regulatory factor (IRF) family members have been implicated as critical transcription factors that function in immune responses, hematopoietic differentiation, and cell growth regulation. Activation of IRF5 results in the production of pro-inflammatory cytokines such as TNFα, IL6, and IL12, as well as type I interferons. In this study, we demonstrate that HIV-2 Vpx interacts with IRF5, and Vpx inhibits IRF5-mediated transactivation. Expression of Vpx in THP-1 cells reduced mRNA levels and protein production of Toll-like receptor-dependent IL6, IL12p40, and TNFα induced by lipopolysaccharide, R848, and ODN2216. Chromatin immunoprecipitation assays show that Vpx expression results in decreased promoter binding activity of IRF5. This study provides new insights into mechanisms employed by HIV-2 to counteract innate immune defenses against viral infection.
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Affiliation(s)
- Xiaogang Cheng
- From the Division of Oncology, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri 63110
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15
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Reinhard C, Bottinelli D, Kim B, Luban J. Vpx rescue of HIV-1 from the antiviral state in mature dendritic cells is independent of the intracellular deoxynucleotide concentration. Retrovirology 2014; 11:12. [PMID: 24485168 PMCID: PMC3923257 DOI: 10.1186/1742-4690-11-12] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2013] [Accepted: 01/28/2014] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND SIVMAC/HIV-2 Vpx recruits the CUL4A-DCAF1 E3 ubiquitin ligase complex to degrade the deoxynucleotide hydrolase SAMHD1. This increases the concentration of deoxynucleotides available for reverse transcription in myeloid cells and resting T cells. Accordingly, transduction of these cells by SIVMAC requires Vpx. Virus-like particles containing SIVMAC Vpx (Vpx-VLPs) also increase the efficiency of HIV-1 transduction in these cells, and rescue transduction by HIV-1, but not SIVMAC, in mature monocyte-derived dendritic cells (MDDCs). Differences in Vpx mechanism noted at that time, along with recent data suggesting that SAMHD1 gains additional restriction capabilities in the presence of type I IFN prompted further examination of the role of Vpx and SAMHD1 in HIV-1 transduction of mature MDDCs. RESULTS When challenged with Vpx-VLPs, SAMHD1 was degraded in MDDCs even after cells had been matured with LPS, though there was no increase in deoxynucleotide levels. Steady-state levels of HIV-1 late reverse transcription products in mature MDDCs were increased to the same extent by either Vpx-VLPs or exogenous nucleosides. In contrast, only Vpx-VLPs increased the levels of 2-LTR circles and proviral DNA in myeloid cells. These results demonstrate that exogenous nucleosides and Vpx-VLPs both increase the levels of HIV-1 cDNA in myeloid cells, but only Vpx-VLPs rescue 2-LTR circles and proviral DNA in myeloid cells with a previously established antiviral state. Finally, since trans-acting Vpx-VLPs provide long-lasting rescue of HIV-1 vector transduction in the face of the antiviral state, and exogenous nucleosides do not, exogenous nucleosides were used to achieve efficient transduction of MDDCs by vectors that stably encode Vprs and Vpxs from a collection of primate lentiviruses. Vpr from SIVDEB or SIVMUS, Vpx from SIVMAC251 or HIV-2, but not SIVRCM, degraded endogenous SAMHD1, increased steady-state levels of HIV-1 cDNA, and rescued HIV-1 from the antiviral state in MDDCs. CONCLUSION Inhibition of deoxynucleotide hydrolysis by promoting SAMHD1 degradation is not the only mechanism by which Vpx rescues HIV-1 in MDDCs from the antiviral state. Vpx has an additional effect on HIV-1 transduction of these cells that occurs after completion of reverse transcription and acts independently of deoxynucleotide levels.
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Affiliation(s)
| | | | | | - Jeremy Luban
- Department of Microbiology and Molecular Medicine, University of Geneva, 1 Rue Michel Servet, Geneva 4 CH-1211, Switzerland.
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Miyake A, Miyazaki Y, Fujita M, Nomaguchi M, Adachi A. Role of poly-proline motif in HIV-2 Vpx expression. Front Microbiol 2014; 5:24. [PMID: 24478770 PMCID: PMC3904113 DOI: 10.3389/fmicb.2014.00024] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2013] [Accepted: 01/14/2014] [Indexed: 11/13/2022] Open
Affiliation(s)
- Ariko Miyake
- Department of Microbiology, Institute of Health Biosciences, The University of Tokushima Graduate School Tokushima, Japan
| | - Yasuyuki Miyazaki
- Department of Microbiology, Institute of Health Biosciences, The University of Tokushima Graduate School Tokushima, Japan
| | - Mikako Fujita
- School of Pharmacy, Research Institute for Drug Discovery, Kumamoto University Kumamoto, Japan
| | - Masako Nomaguchi
- Department of Microbiology, Institute of Health Biosciences, The University of Tokushima Graduate School Tokushima, Japan
| | - Akio Adachi
- Department of Microbiology, Institute of Health Biosciences, The University of Tokushima Graduate School Tokushima, Japan
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Miyake A, Fujita M, Fujino H, Koga R, Kawamura S, Otsuka M, Ode H, Iwatani Y, Sakai Y, Doi N, Nomaguchi M, Adachi A, Miyazaki Y. Poly-proline motif in HIV-2 Vpx is critical for its efficient translation. J Gen Virol 2014; 95:179-189. [DOI: 10.1099/vir.0.057364-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Human immunodeficiency virus type 2 (HIV-2) carries an accessory protein Vpx that is important for viral replication in natural target cells. In its C-terminal region, there is a highly conserved poly-proline motif (PPM) consisting of seven consecutive prolines, encoded in a poly-pyrimidine tract. We have previously shown that PPM is critical for Vpx expression and viral infectivity. To elucidate the molecular basis underlying this observation, we analysed the expression of Vpx proteins with various PPM mutations by in vivo and in vitro systems. We found that the number and position of consecutive prolines in PPM are important for Vpx expression, and demonstrated that PPM is essential for efficient Vpx translation. Furthermore, mutational analysis to synonymously disrupt the poly-pyrimidine tract suggested that the context of PPM amino acid sequences is required for efficient translation of Vpx. We similarly analysed HIV-1 and HIV-2 Vpr proteins structurally related to HIV-2 Vpx. Expression level of the two Vpr proteins lacking PPM was shown to be much lower relative to that of Vpx, and not meaningfully enhanced by introduction of PPM at the C terminus. Finally, we examined the Vpx of simian immunodeficiency virus from rhesus monkeys (SIVmac), which also has seven consecutive prolines, for PPM-dependent expression. A multi-substitution mutation in the PPM markedly reduced the expression level of SIVmac Vpx. Taken together, it can be concluded that the notable PPM sequence enhances the expression of Vpx proteins from viruses of the HIV-2/SIVmac group at the translational level.
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Affiliation(s)
- Ariko Miyake
- Department of Microbiology, Institute of Health Biosciences, University of Tokushima Graduate School, Tokushima, Tokushima, Japan
| | - Mikako Fujita
- Research Institute for Drug Discovery, School of Pharmacy, Kumamoto University, Kumamoto, Kumamoto, Japan
| | - Haruna Fujino
- Department of Bioorganic Medicinal Chemistry, Faculty of Life Sciences, Kumamoto University, Kumamoto, Kumamoto, Japan
| | - Ryoko Koga
- Department of Bioorganic Medicinal Chemistry, Faculty of Life Sciences, Kumamoto University, Kumamoto, Kumamoto, Japan
| | - Sogo Kawamura
- Department of Bioorganic Medicinal Chemistry, Faculty of Life Sciences, Kumamoto University, Kumamoto, Kumamoto, Japan
| | - Masami Otsuka
- Department of Bioorganic Medicinal Chemistry, Faculty of Life Sciences, Kumamoto University, Kumamoto, Kumamoto, Japan
| | - Hirotaka Ode
- Japanese Foundation for AIDS Prevention, Chiyoda-ku, Tokyo, Japan
- Clinical Research Center, National Hospital Organization, Nagoya Medical Center, Nagoya, Aichi, Japan
| | - Yasumasa Iwatani
- Clinical Research Center, National Hospital Organization, Nagoya Medical Center, Nagoya, Aichi, Japan
| | - Yosuke Sakai
- Department of Microbiology, Institute of Health Biosciences, University of Tokushima Graduate School, Tokushima, Tokushima, Japan
| | - Naoya Doi
- Japanese Foundation for AIDS Prevention, Chiyoda-ku, Tokyo, Japan
- Department of Microbiology, Institute of Health Biosciences, University of Tokushima Graduate School, Tokushima, Tokushima, Japan
| | - Masako Nomaguchi
- Department of Microbiology, Institute of Health Biosciences, University of Tokushima Graduate School, Tokushima, Tokushima, Japan
| | - Akio Adachi
- Department of Microbiology, Institute of Health Biosciences, University of Tokushima Graduate School, Tokushima, Tokushima, Japan
| | - Yasuyuki Miyazaki
- Department of Microbiology, Institute of Health Biosciences, University of Tokushima Graduate School, Tokushima, Tokushima, Japan
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Generation of rhesus macaque-tropic HIV-1 clones that are resistant to major anti-HIV-1 restriction factors. J Virol 2013; 87:11447-61. [PMID: 23966385 DOI: 10.1128/jvi.01549-13] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Human immunodeficiency virus type 1 (HIV-1) replication in macaque cells is restricted mainly by antiviral cellular APOBEC3, TRIM5α/TRIM5CypA, and tetherin proteins. For basic and clinical HIV-1/AIDS studies, efforts to construct macaque-tropic HIV-1 (HIV-1mt) have been made by us and others. Although rhesus macaques are commonly and successfully used as infection models, no HIV-1 derivatives suitable for in vivo rhesus research are available to date. In this study, to obtain novel HIV-1mt clones that are resistant to major restriction factors, we altered Gag and Vpu of our best HIV-1mt clone described previously. First, by sequence- and structure-guided mutagenesis, three amino acid residues in Gag-capsid (CA) (M94L/R98S/G114Q) were found to be responsible for viral growth enhancement in a macaque cell line. Results of in vitro TRIM5α susceptibility testing of HIV-1mt carrying these substitutions correlated well with the increased viral replication potential in macaque peripheral blood mononuclear cells (PBMCs) with different TRIM5 alleles, suggesting that the three amino acids in HIV-1mt CA are involved in the interaction with TRIM5α. Second, we replaced the transmembrane domain of Vpu of this clone with the corresponding region of simian immunodeficiency virus SIVgsn166 Vpu. The resultant clone, MN4/LSDQgtu, was able to antagonize macaque but not human tetherin, and its Vpu effectively functioned during viral replication in a macaque cell line. Notably, MN4/LSDQgtu grew comparably to SIVmac239 and much better than any of our other HIV-1mt clones in rhesus macaque PBMCs. In sum, MN4/LSDQgtu is the first HIV-1 derivative that exhibits resistance to the major restriction factors in rhesus macaque cells.
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DeLucia M, Mehrens J, Wu Y, Ahn J. HIV-2 and SIVmac accessory virulence factor Vpx down-regulates SAMHD1 enzyme catalysis prior to proteasome-dependent degradation. J Biol Chem 2013; 288:19116-26. [PMID: 23677995 DOI: 10.1074/jbc.m113.469007] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
SAMHD1, a dGTP-regulated deoxyribonucleoside triphosphate (dNTP) triphosphohydrolase, down-regulates dNTP pools in terminally differentiated and quiescent cells, thereby inhibiting HIV-1 infection at the reverse transcription step. HIV-2 and simian immunodeficiency virus (SIV) counteract this restriction via a virion-associated virulence accessory factor, Vpx (Vpr in some SIVs), which loads SAMHD1 onto CRL4-DCAF1 E3 ubiquitin ligase for polyubiquitination, programming it for proteasome-dependent degradation. However, the detailed molecular mechanisms of SAMHD1 recruitment to the E3 ligase have not been defined. Further, whether divergent, orthologous Vpx proteins, encoded by distinct HIV/SIV strains, bind SAMHD1 in a similar manner, at a molecular level, is not known. We applied surface plasmon resonance analysis to assess the requirements for and kinetics of binding between various primate SAMHD1 proteins and Vpx proteins from SIV or HIV-2 strains. Our data indicate that Vpx proteins, bound to DCAF1, interface with the C terminus of primate SAMHD1 proteins with nanomolar affinity, manifested by rapid association and slow dissociation. Further, we provide evidence that Vpx binding to SAMHD1 inhibits its catalytic activity and induces disassembly of a dGTP-dependent oligomer. Our studies reveal a previously unrecognized biochemical mechanism of Vpx-mediated SAMHD1 inhibition: direct down-modulation of its catalytic activity, mediated by the same binding event that leads to SAMHD1 recruitment to the E3 ubiquitin ligase for proteasome-dependent degradation.
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Affiliation(s)
- Maria DeLucia
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15260, USA
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20
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Takeuchi JS, Perche B, Migraine J, Mercier-Delarue S, Ponscarme D, Simon F, Clavel F, Labrosse B. High level of susceptibility to human TRIM5α conferred by HIV-2 capsid sequences. Retrovirology 2013; 10:50. [PMID: 23647667 PMCID: PMC3691696 DOI: 10.1186/1742-4690-10-50] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2012] [Accepted: 04/12/2013] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND HIV-2, which was transmitted to humans from a distant primate species (sooty mangabey), differs remarkably from HIV-1 in its infectivity, transmissibility and pathogenicity. We have tested the possibility that a greater susceptibility of HIV-2 capsid (CA) to the human restriction factor TRIM5α (hTRIM5α) could contribute to these differences. RESULTS We constructed recombinant clones expressing CA from a variety of HIV-2 viruses in the context of HIV-1 NL4-3-luciferase. CA sequences were amplified from the plasma of HIV-2 infected patients, including 8 subtype A and 7 subtype B viruses. CA from 6 non-epidemic HIV-2 subtypes, 3 HIV-2 CRF01_AB recombinants and 4 SIVsmm viruses were also tested. Susceptibility to hTRIM5α was measured by comparing single-cycle infectivity in human target cells expressing hTRIM5α to that measured in cells in which hTRIM5α activity was inhibited by overexpression of hTRIM5γ.The insertion of HIV-2 CA sequences in the context of HIV-1 did not affect expression and maturation of the HIV-2 CA protein. The level of susceptibility hTRIM5α expressed by viruses carrying HIV-2 CA sequences was up to 9-fold higher than that of HIV-1 NL4-3 and markedly higher than a panel of primary HIV-1 CA sequences. This phenotype was found both for viruses carrying CA from primary HIV-2 sequences and viruses carrying CA from laboratory-adapted HIV-2 clones. High hTRIM5α susceptibility was found in all HIV-2 subtypes. In this series of viruses, susceptibility to hTRIM5α was not significantly affected by the presence of a proline at position 119 or by the number of prolines at positions 119, 159 or 178 in HIV-2 CA. No significant correlation was found between HIV-2 viremia and sensitivity to hTRIM5α. CONCLUSIONS HIV-2 capsid sequences expressed high levels of susceptibility to hTRIM5α. This property, common to all HIV-2 sequences tested, may contribute in part to the lower replication and pathogenicity of this virus in humans.
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Yan J, Kaur S, DeLucia M, Hao C, Mehrens J, Wang C, Golczak M, Palczewski K, Gronenborn AM, Ahn J, Skowronski J. Tetramerization of SAMHD1 is required for biological activity and inhibition of HIV infection. J Biol Chem 2013; 288:10406-17. [PMID: 23426366 PMCID: PMC3624423 DOI: 10.1074/jbc.m112.443796] [Citation(s) in RCA: 125] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
SAMHD1 is a dGTP-activated dNTPase that has been implicated as a modulator of the innate immune response. In monocytes and their differentiated derivatives, as well as in quiescent cells, SAMHD1 strongly inhibits HIV-1 infection and, to a lesser extent, HIV-2 and simian immunodeficiency virus (SIV) because of their virion-associated virulence factor Vpx, which directs SAMHD1 for proteasomal degradation. Here, we used a combination of biochemical and virologic approaches to gain insights into the functional organization of human SAMHD1. We found that the catalytically active recombinant dNTPase is a dGTP-induced tetramer. Chemical cross-linking studies revealed SAMHD1 tetramers in human monocytic cells, in which it strongly restricts HIV-1 infection. The propensity of SAMHD1 to maintain the tetrameric state in vitro is regulated by its C terminus, located outside of the catalytic domain. Accordingly, we show that the C terminus is required for the full ability of SAMHD1 to deplete dNTP pools and to inhibit HIV-1 infection in U937 monocytes. Interestingly, the human SAMHD1 C terminus contains a docking site for HIV-2/SIVmac Vpx and is known to have evolved under positive selection. This evidence indicates that Vpx targets a functionally important element in SAMHD1. Together, our findings imply that SAMHD1 tetramers are the biologically active form of this dNTPase and provide new insights into the functional organization of SAMHD1.
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Affiliation(s)
- Junpeng Yan
- Department of Molecular Biology and Microbiology, Case Western Reserve School of Medicine, Cleveland, Ohio 44106, USA
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Fujita M, Nomaguchi M, Adachi A, Otsuka M. SAMHD1-Dependent and -Independent Functions of HIV-2/SIV Vpx Protein. Front Microbiol 2012; 3:297. [PMID: 22908011 PMCID: PMC3415948 DOI: 10.3389/fmicb.2012.00297] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2012] [Accepted: 07/25/2012] [Indexed: 12/20/2022] Open
Abstract
Both human immunodeficiency virus (HIV) and simian immunodeficiency virus (SIV) encode a unique set of accessory proteins that enhance viral replication in the host. Two similar accessory proteins, Vpx and Vpr, are encoded by HIV-2. In contrast, HIV-1 encodes Vpr but not Vpx. Recent studies have indicated that Vpx counteracts a particular host restriction factor, thereby facilitating reverse transcription in myeloid cells such as monocyte-derived macrophages and monocyte-derived dendritic cells. This mechanism of counteraction is similar to that of the accessory proteins Vif and Vpu which antagonize other host factors. In 2011, the protein SAMHD1 was identified as the restriction factor counteracted by Vpx. Studies have since revealed that SAMHD1 degrades deoxynucleoside triphosphates (dNTPs), which are components of viral genomic cDNA, in order to deprive viruses of dNTPs. Although interactions between SAMHD1 and Vpx continue to be a major research focus, Vpx has also been shown to have an apparent ability to enhance nuclear import of the viral genome in T lymphocytes. This review summarizes the current knowledge regarding SAMHD1-dependent and -independent functions of Vpx, and discusses possible reasons why HIV-2 encodes both Vpx and Vpr, unlike HIV-1.
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Affiliation(s)
- Mikako Fujita
- Research Institute for Drug Discovery, School of Pharmacy, Kumamoto University Kumamoto, Japan
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Lahouassa H, Daddacha W, Hofmann H, Ayinde D, Logue EC, Dragin L, Bloch N, Maudet C, Bertrand M, Gramberg T, Pancino G, Priet S, Canard B, Laguette N, Benkirane M, Transy C, Landau NR, Kim B, Margottin-Goguet F. SAMHD1 restricts the replication of human immunodeficiency virus type 1 by depleting the intracellular pool of deoxynucleoside triphosphates. Nat Immunol 2012; 13:223-228. [PMID: 22327569 PMCID: PMC3771401 DOI: 10.1038/ni.2236] [Citation(s) in RCA: 657] [Impact Index Per Article: 54.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2011] [Accepted: 01/13/2012] [Indexed: 02/06/2023]
Abstract
SAMHD1 restricts the infection of dendritic and other myeloid cells by human immunodeficiency virus type 1 (HIV-1), but in lentiviruses of the simian immunodeficiency virus of sooty mangabey (SIVsm)-HIV-2 lineage, SAMHD1 is counteracted by the virion-packaged accessory protein Vpx. Here we found that SAMHD1 restricted infection by hydrolyzing intracellular deoxynucleoside triphosphates (dNTPs), lowering their concentrations to below those required for the synthesis of the viral DNA by reverse transcriptase (RT). SAMHD1-mediated restriction was alleviated by the addition of exogenous deoxynucleosides. An HIV-1 with a mutant RT with low affinity for dNTPs was particularly sensitive to SAMHD1-mediated restriction. Vpx prevented the SAMHD1-mediated decrease in dNTP concentration and induced the degradation of human and rhesus macaque SAMHD1 but had no effect on mouse SAMHD1. Nucleotide-pool depletion could be a general mechanism for protecting cells from infectious agents that replicate through a DNA intermediate.
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Affiliation(s)
- Hichem Lahouassa
- Inserm, U1016, Institut Cochin, 27 rue du faubourg St Jacques, Bat G. Roussy, 75014 Paris France
- Cnrs, UMR8104, Paris, France
- Univ Paris Descartes, Paris, France
| | - Waaqo Daddacha
- Department of Microbiology and Immunology, University of Rochester Medical Center, 601 Elmwood Avenue, Rochester, NY 14642, USA
| | - Henning Hofmann
- New York University School of Medicine, Microbiology Department, 550 First Ave., New York, NY 10016, USA
| | - Diana Ayinde
- Inserm, U1016, Institut Cochin, 27 rue du faubourg St Jacques, Bat G. Roussy, 75014 Paris France
- Cnrs, UMR8104, Paris, France
- Univ Paris Descartes, Paris, France
| | - Eric C. Logue
- New York University School of Medicine, Microbiology Department, 550 First Ave., New York, NY 10016, USA
| | - Loïc Dragin
- Inserm, U1016, Institut Cochin, 27 rue du faubourg St Jacques, Bat G. Roussy, 75014 Paris France
- Cnrs, UMR8104, Paris, France
- Univ Paris Descartes, Paris, France
| | - Nicolin Bloch
- New York University School of Medicine, Microbiology Department, 550 First Ave., New York, NY 10016, USA
| | - Claire Maudet
- Inserm, U1016, Institut Cochin, 27 rue du faubourg St Jacques, Bat G. Roussy, 75014 Paris France
- Cnrs, UMR8104, Paris, France
- Univ Paris Descartes, Paris, France
| | - Matthieu Bertrand
- Inserm, U1016, Institut Cochin, 27 rue du faubourg St Jacques, Bat G. Roussy, 75014 Paris France
- Cnrs, UMR8104, Paris, France
- Univ Paris Descartes, Paris, France
| | - Thomas Gramberg
- Virologisches Institut, Klinische und Molekulare Virologie, Universitat Erlangen-Nurnberg, 91054 Erlangen
| | - Gianfranco Pancino
- Institut Pasteur, Unité de Régulation des Infections Rétrovirales, 25 rue du Dr Roux, 75724 Paris Cedex 15, France
| | - Stéphane Priet
- Laboratoire d’Architecture et Fonction des Macromolécules Biologiques, UMR6098, CNRS-Universitéd’Aix-Marseille, 13288 Marseille cedex 09, France
| | - Bruno Canard
- Laboratoire d’Architecture et Fonction des Macromolécules Biologiques, UMR6098, CNRS-Universitéd’Aix-Marseille, 13288 Marseille cedex 09, France
| | - Nadine Laguette
- Institut de Génétique Humaine, Laboratoire de Virologie Moléculaire, CNRS UPR1142, Montpellier 34000, France
| | - Monsef Benkirane
- Institut de Génétique Humaine, Laboratoire de Virologie Moléculaire, CNRS UPR1142, Montpellier 34000, France
| | - Catherine Transy
- Inserm, U1016, Institut Cochin, 27 rue du faubourg St Jacques, Bat G. Roussy, 75014 Paris France
- Cnrs, UMR8104, Paris, France
- Univ Paris Descartes, Paris, France
| | - Nathaniel R. Landau
- New York University School of Medicine, Microbiology Department, 550 First Ave., New York, NY 10016, USA
| | - Baek Kim
- Department of Microbiology and Immunology, University of Rochester Medical Center, 601 Elmwood Avenue, Rochester, NY 14642, USA
| | - Florence Margottin-Goguet
- Inserm, U1016, Institut Cochin, 27 rue du faubourg St Jacques, Bat G. Roussy, 75014 Paris France
- Cnrs, UMR8104, Paris, France
- Univ Paris Descartes, Paris, France
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Pertel T, Reinhard C, Luban J. Vpx rescues HIV-1 transduction of dendritic cells from the antiviral state established by type 1 interferon. Retrovirology 2011; 8:49. [PMID: 21696578 PMCID: PMC3130655 DOI: 10.1186/1742-4690-8-49] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2011] [Accepted: 06/22/2011] [Indexed: 01/08/2023] Open
Abstract
Background Vpx is a virion-associated protein encoded by SIVSM, a lentivirus endemic to the West African sooty mangabey (Cercocebus atys). HIV-2 and SIVMAC, zoonoses resulting from SIVSM transmission to humans or Asian rhesus macaques (Macaca mulatta), also encode Vpx. In myeloid cells, Vpx promotes reverse transcription and transduction by these viruses. This activity correlates with Vpx binding to DCAF1 (VPRBP) and association with the DDB1/RBX1/CUL4A E3 ubiquitin ligase complex. When delivered experimentally to myeloid cells using VSV G-pseudotyped virus-like particles (VLPs), Vpx promotes reverse transcription of retroviruses that do not normally encode Vpx. Results Here we show that Vpx has the extraordinary ability to completely rescue HIV-1 transduction of human monocyte-derived dendritic cells (MDDCs) from the potent antiviral state established by prior treatment with exogenous type 1 interferon (IFN). The magnitude of rescue was up to 1,000-fold, depending on the blood donor, and was also observed after induction of endogenous IFN and IFN-stimulated genes (ISGs) by LPS, poly(I:C), or poly(dA:dT). The effect was relatively specific in that Vpx-associated suppression of soluble IFN-β production, of mRNA levels for ISGs, or of cell surface markers for MDDC differentiation, was not detected. Vpx did not rescue HIV-2 or SIVMAC transduction from the antiviral state, even in the presence of SIVMAC or HIV-2 VLPs bearing additional Vpx, or in the presence of HIV-1 VLPs bearing all accessory genes. In contrast to the effect of Vpx on transduction of untreated MDDCs, HIV-1 rescue from the antiviral state was not dependent upon Vpx interaction with DCAF1 or on the presence of DCAF1 within the MDDC target cells. Additionally, although Vpx increased the level of HIV-1 reverse transcripts in MDDCs to the same extent whether or not MDDCs were treated with IFN or LPS, Vpx rescued a block specific to the antiviral state that occurred after HIV-1 cDNA penetrated the nucleus. Conclusion Vpx provides a tool for the characterization of a potent, new HIV-1 restriction activity, which acts in the nucleus of type 1 IFN-treated dendritic cells.
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Affiliation(s)
- Thomas Pertel
- Department of Microbiology and Molecular Medicine, University of Geneva, Geneva, Switzerland
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Fujita M, Otsuka M, Nomaguchi M, Adachi A. Multifaceted activity of HIV Vpr/Vpx proteins: the current view of their virological functions. Rev Med Virol 2010; 20:68-76. [PMID: 20069611 DOI: 10.1002/rmv.636] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Primate immunodeficiency viruses encode viral proteins that are uniquely auxiliary to their growth in host cells. Of these accessory proteins, those designated Vpr and Vpx are least well understood with respect to their functions in the viral replication cycle. Moreover, their assigned roles based on the results in published studies remain controversial. This review summarises current knowledge on human immunodeficiency virus (HIV) Vpr/Vpx proteins, and discusses their functional activities during the viral life cycle in macrophages and T lymphocytes, the two major target cells of HIV infection.
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Affiliation(s)
- Mikako Fujita
- Research Institute for Drug Discovery, School of Pharmacy, Kumamoto University, Kumamoto 862-0973, Japan
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Ayinde D, Maudet C, Transy C, Margottin-Goguet F. Limelight on two HIV/SIV accessory proteins in macrophage infection: is Vpx overshadowing Vpr? Retrovirology 2010; 7:35. [PMID: 20380700 PMCID: PMC2867959 DOI: 10.1186/1742-4690-7-35] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2009] [Accepted: 04/09/2010] [Indexed: 01/16/2023] Open
Abstract
HIV viruses encode a set of accessory proteins, which are important determinants of virulence due to their ability to manipulate the host cell physiology for the benefit of the virus. Although these viral proteins are dispensable for viral growth in many in vitro cell culture systems, they influence the efficiency of viral replication in certain cell types. Macrophages are early targets of HIV infection which play a major role in viral dissemination and persistence in the organism. This review focuses on two HIV accessory proteins whose functions might be more specifically related to macrophage infection: Vpr, which is conserved across primate lentiviruses including HIV-1 and HIV-2, and Vpx, a protein genetically related to Vpr, which is unique to HIV-2 and a subset of simian lentiviruses. Recent studies suggest that both Vpr and Vpx exploit the host ubiquitination machinery in order to inactivate specific cellular proteins. We review here why it remains difficult to decipher the role of Vpr in macrophage infection by HIV-1 and how recent data underscore the ability of Vpx to antagonize a restriction factor which counteracts synthesis of viral DNA in monocytic cells.
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Affiliation(s)
- Diana Ayinde
- Institut Cochin, Université Paris Descartes, CNRS (UMR 8104), Paris, France
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27
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Abstract
The HIV genome encodes several accessory proteins (Vif, Vpr, Vpx, Vpu, and Nef) unique to primate lentiviruses, in addition to the structural (Gag, Pol, and Env) and regulatory (Tat and Rev) proteins. Early studies showed that deletion of accessory proteins has a small or no effect on virus replication in cell cultures. However, recent studies have clearly demonstrated that these proteins are essential for efficient viral replication, dissemination, pathogenicity, and disease progression. Here, we summarize the current knowledge of HIV accessory proteins and their cellular targets, and discuss the functional roles of these biologically unique and important viral proteins for virus replication in vitro and in vivo.
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Affiliation(s)
- Masako Nomaguchi
- Department of Microbiology, Institute of Health Biosciences, The University of Tokushima Graduate School, 3-18-15, Kuramoto, Tokushima 770-8503, Japan
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The human immunodeficiency virus type 2 Vpx protein usurps the CUL4A-DDB1 DCAF1 ubiquitin ligase to overcome a postentry block in macrophage infection. J Virol 2009; 83:4854-60. [PMID: 19264781 DOI: 10.1128/jvi.00187-09] [Citation(s) in RCA: 102] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The human immunodeficiency virus (HIV) and simian immunodeficiency virus (SIV) genomes encode several auxiliary proteins that have increasingly shown their importance in the virus-host relationship. One of these proteins, Vpx, is unique to the HIV-2/SIVsm lineage and is critical for viral replication in macrophages. The functional basis for this requirement, as well as the Vpx mode of action, has remained unexplained, and it is all the more enigmatic that HIV type 1 (HIV-1), which has no Vpx counterpart, can infect macrophages. Here, we underscore DCAF1 as a critical host effector of Vpx in its ability to mediate infection and long-term replication of HIV-2 in human macrophages. Vpx assembles with the CUL4A-DDB1 ubiquitin ligase through DCAF1 recruitment. Precluding Vpx present in the incoming virions from recruiting DCAF1 in target macrophages leads to a postentry block characterized by defective accumulation of HIV-2 reverse transcripts. In addition, Vpx from SIVsm functionally complements Vpx-defective HIV-2 in a DCAF1-binding-dependent manner. Altogether, our data point to a mechanism in which Vpx diverts the Cul4A-DDB1(DCAF1) ligase to inactivate an evolutionarily conserved factor, which restricts macrophage infection by HIV-2 and closely related simian viruses.
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Fujita M, Otsuka M, Nomaguchi M, Adachi A. Functional region mapping of HIV-2 Vpx protein. Microbes Infect 2008; 10:1387-92. [DOI: 10.1016/j.micinf.2008.08.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2008] [Revised: 08/04/2008] [Accepted: 08/06/2008] [Indexed: 11/17/2022]
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Characterization of simian immunodeficiency virus SIVSM/human immunodeficiency virus type 2 Vpx function in human myeloid cells. J Virol 2008; 82:12335-45. [PMID: 18829761 DOI: 10.1128/jvi.01181-08] [Citation(s) in RCA: 113] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Human immunodeficiency virus type 2 (HIV-2)/simian immunodeficiency virus SIV(SM) Vpx is incorporated into virion particles and is thus present during the early steps of infection, when it has been reported to influence the nuclear import of viral DNA. We recently reported that Vpx promoted the accumulation of full-length viral DNA following the infection of human monocyte-derived dendritic cells (DCs). This positive effect was exerted following the infection of DCs with cognate viruses and with retroviruses as divergent as HIV-1, feline immunodeficiency virus, and even murine leukemia virus, leading us to suggest that Vpx counteracted an antiviral restriction present in DCs. Here, we show that Vpx is required, albeit to a different extent, for the infection of all myeloid but not of lymphoid cells, including monocytes, macrophages, and monocytoid THP-1 cells that had been induced to differentiate with phorbol esters. The intracellular localization of Vpx was highly heterogeneous and cell type dependent, since Vpx localized differently in HeLa cells and DCs. Despite these differences, no clear correlation between the functionality of Vpx and its intracellular localization could be drawn. As a first insight into its function, we determined that SIV(SM)/HIV-2 and SIV(RCM) Vpx proteins interact with the DCAF1 adaptor of the Cul4-based E3 ubiquitin ligase complex recently described to associate with HIV-1 Vpr and HIV-2 Vpx. However, the functionality of Vpx proteins in the infection of DCs did not strictly correlate with DCAF1 binding, and knockdown experiments failed to reveal a functional role for this association in differentiated THP-1 cells. Lastly, when transferred in the context of a replication-competent viral clone, Vpx was required for replication in DCs.
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31
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Vpx is critical for reverse transcription of the human immunodeficiency virus type 2 genome in macrophages. J Virol 2008; 82:7752-6. [PMID: 18495778 DOI: 10.1128/jvi.01003-07] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The abilities of wild-type and vpx-defective human immunodeficiency virus type 2 (HIV-2) clones to synthesize viral DNA in human monocyte-derived macrophages (MDMs) and lymphocytic cells were comparatively and quantitatively evaluated. While the vpx-defective mutant directed the synthesis of viral DNA comparably to the wild-type virus and normally in lymphocytic cells, no appreciable viral DNA was detected in MDMs infected with the mutant. To substantiate this finding and to determine whether there is some specific region(s) in Vpx crucial for viral DNA synthesis in MDMs, we generated a series of site-specific point mutants of vpx and examined their phenotypes. The resultant five mutants, with no infectivity for MDMs, showed, without exception, the same defect as the vpx-defective mutant. Our results here clearly demonstrated that the entire Vpx protein is critical for reverse transcription of the HIV-2 genome in human MDMs.
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SIVSM/HIV-2 Vpx proteins promote retroviral escape from a proteasome-dependent restriction pathway present in human dendritic cells. Retrovirology 2007; 4:2. [PMID: 17212817 PMCID: PMC1779362 DOI: 10.1186/1742-4690-4-2] [Citation(s) in RCA: 171] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2006] [Accepted: 01/09/2007] [Indexed: 01/03/2023] Open
Abstract
Background Vpx is a non-structural protein coded by members of the SIVSM/HIV-2 lineage that is believed to have originated by duplication of the common vpr gene present in primate lentiviruses. Vpx is incorporated into virion particles and is thus present during the early steps of viral infection, where it is thought to drive nuclear import of viral nucleoprotein complexes. We have previously shown that Vpx is required for SIVMAC-derived lentiviral vectors (LVs) infection of human monocyte-derived dendritic cells (DCs). However, since the requirement for Vpx is specific for DCs and not for other non-dividing cell types, this suggests that Vpx may play a role other than nuclear import. Results Here, we show that the function of Vpx in the infection of DCs is conserved exclusively within the SIVSM/HIV-2 lineage. At a molecular level, Vpx acts by promoting the accumulation of full length viral DNA. Furthermore, when supplied in target cells prior to infection, Vpx exerts a similar effect following infection of DCs with retroviruses as divergent as primate and feline lentiviruses and gammaretroviruses. Lastly, the effect of Vpx overlaps with that of the proteasome inhibitor MG132 in DCs. Conclusion Overall, our results support the notion that Vpx modifies the intracellular milieu of target DCs to facilitate lentiviral infection. The data suggest that this is achieved by promoting viral escape from a proteasome-dependent pathway especially detrimental to viral infection in DCs.
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Piroozmand A, Khamsri B, Fujita M, Adachi A, Uchiyama T. Morphological study on biologically distinct vpx/vpr mutants of HIV-2. THE JOURNAL OF MEDICAL INVESTIGATION 2006; 53:271-6. [PMID: 16953064 DOI: 10.2152/jmi.53.271] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
We have previously shown that human immunodeficiency virus type 2 (HIV-2) without functional vpx and vpr genes is severely defective for viral growth in lymphocytic cells, and suggested that the virions produced in the absence of Vpx and Vpr are critically damaged. To examine the nature of replication-defect for the vpx/vpr double mutant, we quantitatively and morphologically studied the virions produced in cells transfected or infected with wild type clone, single (vpx and vpr mutants) or the double mutant. While no significant difference in virion production was found for various virus clones in transfected cells, a major growth retardation in infected cells was readily observed for the vpx and vpx/vpr mutants. In particular, no viral growth was detected for the double mutant. By contrast to the very distinct growth characteristics of the three mutant clones, no appreciable difference in virion morphology was noted. These results indicated that Vpx and Vpr of HIV-2 may cooperatively contribute to virion infectivity without affecting virion morphogenesis.
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Affiliation(s)
- Ahmad Piroozmand
- Department of Virology, Institute of Health Biosciences, The University of Tokushima Graduate School
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34
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Mahnke LA, Belshan M, Ratner L. Analysis of HIV-2 Vpx by modeling and insertional mutagenesis. Virology 2006; 348:165-74. [PMID: 16457868 DOI: 10.1016/j.virol.2005.12.023] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2005] [Revised: 11/22/2005] [Accepted: 12/09/2005] [Indexed: 11/27/2022]
Abstract
Vpx facilitates HIV-2 nuclear localization by a poorly understood mechanism. We have compared Vpx to an NMR structure HIV-1 Vpr in a central helical domain and probed regions of Vpx by insertional mutagenesis. A predicted loop between helices two and three appears to be unique, overlapping with a known novel nuclear localization signal. Overall, Vpx was found to be surprisingly flexible, tolerating a series of large insertions. We found that insertion within the polyproline-containing C-terminus destabilizes nuclear localization, whereas mutating a second helix in the central domain disrupts viral packaging. Other insertional mutants in the predicted loop and in a linker region between the central domain and the C-terminus may be useful as sites of intramolecular tags as they could be packaged adequately and retained preintegration complex associated integration activity in a serum starvation assay. An unexpected result was found within a previously defined nuclear localization motif near aa 71. This mutant retained robust nuclear localization in a GFP fusion assay and was competent for preintegration complex associated nuclear import. In summary, we have modeled helical content in Vpx and assessed potential sites of intramolecular tags which may prove useful for protein-protein interactions studies.
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MESH Headings
- Amino Acid Sequence
- Cell Nucleus/chemistry
- Gene Products, vpr/chemistry
- Genes, Reporter
- Green Fluorescent Proteins/analysis
- HIV-2/chemistry
- HIV-2/genetics
- HIV-2/physiology
- Microscopy, Fluorescence
- Models, Molecular
- Molecular Sequence Data
- Mutagenesis, Insertional
- Nuclear Magnetic Resonance, Biomolecular
- Protein Structure, Secondary
- Protein Structure, Tertiary/genetics
- Protein Structure, Tertiary/physiology
- Protein Transport
- Sequence Alignment
- Viral Regulatory and Accessory Proteins/analysis
- Viral Regulatory and Accessory Proteins/chemistry
- Viral Regulatory and Accessory Proteins/genetics
- Viral Regulatory and Accessory Proteins/physiology
- Virus Assembly/genetics
- vpr Gene Products, Human Immunodeficiency Virus
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Affiliation(s)
- Lisa A Mahnke
- Department of Medicine, Divisions of Oncology and Infections Diseases, Washington University School of Medicine, PO Box 8069, 660 South Euclid Avenue, Saint Louis, MO 63110, USA.
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Khamsri B, Murao F, Yoshida A, Sakurai A, Uchiyama T, Shirai H, Matsuo Y, Fujita M, Adachi A. Comparative study on the structure and cytopathogenic activity of HIV Vpr/Vpx proteins. Microbes Infect 2005; 8:10-5. [PMID: 16153874 DOI: 10.1016/j.micinf.2005.05.020] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2005] [Revised: 05/19/2005] [Accepted: 05/19/2005] [Indexed: 11/23/2022]
Abstract
The three-dimensional (3-D) structure of human immunodeficiency virus type 2 (HIV-2) Vpr/Vpx was predicted by homology modeling based on the NMR structure of human immunodeficiency virus type 1 (HIV-1) Vpr. The three proteins similarly have three major amphipathic alpha-helices. In contrast to HIV-1 Vpr, Vpr/Vpx of HIV-2 have a long N-terminal loop and clustered prolines in the second half of the C-terminal loop. HIV-2 Vpx uniquely contains a long region between the second and third major helices, and bears several glycines in the first half of the C-terminal loop. Instead of the glycines, there is a group of hydrophilic amino acids and arginines in the corresponding regions of the two Vprs. To compare the cytopathogenic potentials of HIV-1 Vpr and HIV-2 Vpr/Vpx, we examined the production of luciferase as a marker of cell damage. We further analyzed the characteristics of cells transduced with vpr/vpx genes driven by an inducible promoter. The results obtained clearly show that structurally similar, but distinct, HIV Vpr/Vpx proteins are detrimental to target cells.
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Affiliation(s)
- Boonruang Khamsri
- Department of Virology, Institute of Health Biosciences, The University of Tokushima Graduate School, Tokushima 770-8503, Japan
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36
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Ueno F, Shiota H, Miyaura M, Yoshida A, Sakurai A, Tatsuki J, Koyama AH, Akari H, Adachi A, Fujita M. Vpx and Vpr proteins of HIV-2 up-regulate the viral infectivity by a distinct mechanism in lymphocytic cells. Microbes Infect 2003; 5:387-95. [PMID: 12737994 DOI: 10.1016/s1286-4579(03)00042-x] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Mutants of human immunodeficiency virus type 2 (HIV-2) carrying a frame-shift mutation in vpx, vpr, and in both genes were monitored for their growth potentials in a newly established lymphocytic cell line, HSC-F. Worthy of note, the replication of a vpx single mutant, but not vpr, was severely impaired in these cells, and that of a vpx-vpr double mutant was more damaged. Defective replication sites of the vpx single and vpx-vpr double mutants were demonstrated to be mapped, respectively, to the nuclear import of viral genome, and to both, this process and the virus assembly/release stage. While the mutational effect of vpr was small, the replication efficiency in one cycle of the vpx mutant relative to that of wild-type virus was estimated to be 10%. The growth phenotypes of the vpx, vpr, and vpx-vpr mutant viruses in HSC-F cells were essentially repeated in primary human lymphocytes. In primary human macrophages, whereas the vpx and vpx-vpr mutants did not grow at all, the vpr mutant grew equally as well as the wild-type virus. These results strongly suggested that Vpx is critical for up-regulation of HIV-2 replication in natural target cells by enhancing the genome nuclear import, and that Vpr promotes HIV-2 replication somewhat, at least in lymphocytic cells, at a very late replication phase.
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Affiliation(s)
- Fumiko Ueno
- Department of Ophthalmology and Visual Neuroscience, The University of Tokushima School of Medicine, Tokushima 770-8503, Japan
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37
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Haddrick M, Brown CR, Plishka R, Buckler-White A, Hirsch VM, Ginsberg H. Biologic studies of chimeras of highly and moderately virulent molecular clones of simian immunodeficiency virus SIVsmPBj suggest a critical role for envelope in acute AIDS virus pathogenesis. J Virol 2001; 75:6645-59. [PMID: 11413332 PMCID: PMC114388 DOI: 10.1128/jvi.75.14.6645-6659.2001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Previous studies identified three molecular clones of the acutely pathogenic SIVsmPBj strain that varied in terms of relative in vivo pathogenicity. One clone, SIVsmPBj6.6, reproducibly induced a rapidly fatal disease in pigtailed macaques. In contrast, a highly related clone (SIVsmPBj6.9) was only minimally pathogenic in macaques. PBj6.6 and PBj6.9 shared a tyrosine substitution at position 17 in the Nef protein that is a major determinant of virulence but differed at one residue in Vpx (C89R), three residues within the envelope (D119G, R871G, G872R), and a single residue in Nef (F252L). SIVsmPBj6.9 was less efficient in inducing proliferation of resting macaque peripheral blood mononuclear cells in vitro than SIVsmPBj6.6 and exhibited a marked reduction in infectivity relative to SIVsmPBj6.6. Chimeric viruses for each of these variable residues were constructed, and their biologic properties were compared to those of the parental strains. Differences in Vpx and Nef did not alter the basic biologic phenotype of the chimeras. However, the D119G substitution in the envelope of SIVsmPBj6.9 was associated with a marked reduction in the infectivity of this virus relative to SIVsmPBj6.6. An associated processing defect in gp160 of SIVsmPBj6.9 and chimeras expressing the D119G substitution suggests that a reduction in virion envelope incorporation is the mechanistic basis for reduced virion infectivity. In vivo studies revealed that substitution of the PBj6.9 amino acid into PBj6.6 (D119) abrogated the pathogenicity of this previously pathogenic virus. Introduction of the PBj6.9 G119, however, did not confer full virulence to the parental PBj6.9 virus, implicating one or all of the other four substitutions in the virulence of SIVsmPBj6.6.
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Affiliation(s)
- M Haddrick
- Laboratory of Molecular Microbiology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Twinbrook II Facility, 12441 Parklawn Dr., Rockville, MD 20852, USA
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Koh K, Miyaura M, Yoshida A, Sakurai A, Fujita M, Adachi A. Cell-dependent gag mutants of HIV-1 are crucially defective at the stage of uncoating/reverse transcription in non-permissive cells. Microbes Infect 2000; 2:1419-23. [PMID: 11099927 DOI: 10.1016/s1286-4579(00)01295-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
We have previously shown that some of the human immunodeficiency virus type 1 (HIV-1) gag matrix (MA), capsid (CA), and nucleocapsid (NC) mutants display host-cell-dependent replication potential, and that they are defective at the early phase of the virus replication cycle in non-permissive cells. To determine the defective replication stage of the cell-dependent mutants precisely, the processes of virus entry into cells and virus DNA synthesis were monitored by the highly sensitive enzyme-linked immunosorbent assay and polymerase chain reaction amplification analysis. The results obtained indicated that all the cell-dependent MA, CA and NC mutants are defective at the stage of uncoating/reverse transcription, and that a cellular factor(s) is involved in this process.
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Affiliation(s)
- K Koh
- Department of Virology, School of Medicine, The University of Tokushima, 770-8503, Tokushima, Japan
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Shimano R, Inubushi R, Fukumori T, Tamaki M, Oshima Y, Kawamura M, Adachi A. Suppression of HIV-2 replication by HIV-1 gag mutants. Biochem Biophys Res Commun 1998; 248:418-21. [PMID: 9675152 DOI: 10.1006/bbrc.1998.8975] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Gag gene mutants of human immunodeficiency virus type 1 (HIV-1) were analyzed for their potentials of inhibiting the replication of wild-type (wt) HIV-2, the second AIDS virus, in a single-round of viral replication. Of twenty-two HIV-1 gag mutants examined, seven were found to efficiently interfere with the replication of wt HIV-2. Some mutants, which can suppress the replication of wt HIV-1, did not show this inhibitory effect. These mutants were defective at the late phase of viral replication. A mutant designated NL-C1a was demonstrated to be very effective against the replication of HIV-1 and HIV-2 in monocytic cells as well as in lymphocytic cells.
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Affiliation(s)
- R Shimano
- Department of Virology, The University of Tokushima School of Medicine, Tokushima, 770-8503, Japan
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40
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Shimano R, Inubushi R, Amano K, Ogasawa T, Adachi A. Gag-Pol region determines the tropism of SIVagm for human cells. Virus Genes 1998; 16:137-9. [PMID: 9608656 DOI: 10.1023/a:1007971620863] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Simian immunodeficiency virus isolated from African green monkeys (SIVagm) does not grow in many of human cell lines such as CEM x 174, H9, and MT-4, but could replicate in some human cell lines. Sequence of SIVagm responsible for its narrow host range was determined by making and monitoring growth potential of chimeric clones between SIVagm and human immunodeficiency virus type 1 (HIV-1). The results obtained indicated that the gag-pol region determines the observed narrow host range. By monitoring virus DNA synthesis and progeny virion production, the defect(s) of SIVagm in the replication in the restricted cells was demonstrated to be located at early phase.
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Affiliation(s)
- R Shimano
- Department of Virology, School of Medicine, University of Tokushima, Japan
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41
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Shimano R, Iida S, Fukumori T, Yamamoto Y, Kawamura M, Furuta RA, Adachi A. Inhibition of HIV replication by capsid mutant C6b. Biochem Biophys Res Commun 1998; 242:313-6. [PMID: 9446791 DOI: 10.1006/bbrc.1997.7963] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
A Gag capsid mutant of human immunodeficiency virus type 1 (HIV-1) designated C6b was biologically and biochemically characterized with respect to its ability to suppress the replication of wild-type (wt) HIV. The C6b efficiently interfered with the replication of wt HIV-1 in the cleavage of Gag precursor, and also in the early replication process before or during viral DNA synthesis after viral penetration. The C6b Gag appeared to be unable to form chimeric multimers with HIV-2 Gag and failed to inhibit the replication of wt HIV-2.
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Affiliation(s)
- R Shimano
- Department of Virology, School of Medicine, University of Tokushima, Japan
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42
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Campbell BJ, Hirsch VM. Vpr of simian immunodeficiency virus of African green monkeys is required for replication in macaque macrophages and lymphocytes. J Virol 1997; 71:5593-602. [PMID: 9188633 PMCID: PMC191801 DOI: 10.1128/jvi.71.7.5593-5602.1997] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
The genomes of simian immunodeficiency viruses isolated from African green monkeys (SIVagm) contain a single accessory gene homolog of human immunodeficiency virus type 1 (HIV-1) vpr. This genomic organization differs from that of SIVsm-SIVmac-HIV-2 group viruses, which contain two gene homologs, designated vpr and vpx, which in combination appear to share the functions of HIV-1 vpr. The in vitro role of the SIVagm homolog was evaluated with molecularly cloned, pathogenic SIVagm9063-2. These studies revealed that this gene shares properties of HIV-1 vpr, such as nuclear and virion localization. In addition, SIVagm mutants with inactivating mutations of vpr are unable to replicate in nondividing cells, such as macaque monocyte-derived macrophages, but replicate to almost wild-type levels in a susceptible human T-cell line. The transport of virus preintegration complexes into the nucleus in primary macrophages, as measured by the production of unintegrated circular viral DNA, is less efficient for the mutant viruses than it is for the wild-type virus. SIVagm mutants also replicate inefficiently in primary macaque peripheral blood mononuclear cells, with a propensity for substitutions that remove the inserted inactivating stop codon. These data, in conjunction with recent findings that the Vpr protein is capable of inducing G2 arrest, are consistent with designation of this SIVagm accessory gene as vpr to reflect its shared functions and properties with HIV-1 vpr.
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Affiliation(s)
- B J Campbell
- Laboratory of Infectious Diseases, National Institute of Allergy and Infectious Diseases, NIH Twinbrook II Facility, Rockville, Maryland 20852, USA
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