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Sarkar R, Chhabra S, Tanwar M, Agarwal N, Kalia M. Japanese encephalitis virus hijacks ER-associated degradation regulators for its replication. J Gen Virol 2024; 105. [PMID: 38787366 DOI: 10.1099/jgv.0.001995] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/25/2024] Open
Abstract
Flaviviruses target their replication on membranous structures derived from the ER, where both viral and host proteins play crucial structural and functional roles. Here, we have characterized the involvement of the ER-associated degradation (ERAD) pathway core E3 ligase complex (SEL1L-HRD1) regulator proteins in the replication of Japanese encephalitis virus (JEV). Through high-resolution immunofluorescence imaging of JEV-infected HeLa cells, we observe that the virus replication complexes marked by NS1 strongly colocalize with the ERAD adapter SEL1L, lectin OS9, ER-membrane shuttle factor HERPUD1, E3 ubiquitin ligase HRD1 and rhomboid superfamily member DERLIN1. NS5 positive structures also show strong overlap with SEL1L. While these effectors show significant transcriptional upregulation, their protein levels remain largely stable in infected cells. siRNA mediated depletion of OS9, SEL1L, HERPUD1 and HRD1 significantly inhibit viral RNA replication and titres, with SEL1L depletion showing the maximum attenuation of replication. By performing protein translation arrest experiments, we show that SEL1L, and OS9 are stabilised upon JEV infection. Overall results from this study suggest that these ERAD effector proteins are crucial host-factors for JEV replication.
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Affiliation(s)
- Riya Sarkar
- Virology Research Group, Regional Centre for Biotechnology, NCR Biotech Science Cluster, Faridabad, 121001, India
- Centre for Tuberculosis Research, Translational Health Science and Technology Institute, NCR Biotech Science Cluster, Faridabad, 121001, India
- Present address: Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Simran Chhabra
- Virology Research Group, Regional Centre for Biotechnology, NCR Biotech Science Cluster, Faridabad, 121001, India
| | - Mukesh Tanwar
- Virology Research Group, Regional Centre for Biotechnology, NCR Biotech Science Cluster, Faridabad, 121001, India
| | - Nisheeth Agarwal
- Centre for Tuberculosis Research, Translational Health Science and Technology Institute, NCR Biotech Science Cluster, Faridabad, 121001, India
| | - Manjula Kalia
- Virology Research Group, Regional Centre for Biotechnology, NCR Biotech Science Cluster, Faridabad, 121001, India
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2
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Selinger M, Novotný R, Sýs J, Roby JA, Tykalová H, Ranjani GS, Vancová M, Jaklová K, Kaufman F, Bloom ME, Zdráhal Z, Grubhoffer L, Forwood JK, Hrabal R, Rumlová M, Štěrba J. Tick-borne encephalitis virus capsid protein induces translational shut-off as revealed by its structural-biological analysis. J Biol Chem 2022; 298:102585. [PMID: 36223838 PMCID: PMC9664413 DOI: 10.1016/j.jbc.2022.102585] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Revised: 09/29/2022] [Accepted: 10/02/2022] [Indexed: 11/05/2022] Open
Abstract
Tick-borne encephalitis virus (TBEV) is the most medically relevant tick-transmitted Flavivirus in Eurasia, targeting the host central nervous system and frequently causing severe encephalitis. The primary function of its capsid protein (TBEVC) is to recruit the viral RNA and form a nucleocapsid. Additional functionality of Flavivirus capsid proteins has been documented, but further investigation is needed for TBEVC. Here, we show the first capsid protein 3D structure of a member of the tick-borne flaviviruses group. The structure of monomeric Δ16-TBEVC was determined using high-resolution multidimensional NMR spectroscopy. Based on natural in vitro TBEVC homodimerization, the dimeric interfaces were identified by hydrogen deuterium exchange mass spectrometry (MS). Although the assembly of flaviviruses occurs in endoplasmic reticulum-derived vesicles, we observed that TBEVC protein also accumulated in the nuclei and nucleoli of infected cells. In addition, the predicted bipartite nuclear localization sequence in the TBEVC C-terminal part was confirmed experimentally, and we described the interface between TBEVC bipartite nuclear localization sequence and import adapter protein importin-alpha using X-ray crystallography. Furthermore, our coimmunoprecipitation coupled with MS identification revealed 214 interaction partners of TBEVC, including viral envelope and nonstructural NS5 proteins and a wide variety of host proteins involved mainly in rRNA processing and translation initiation. Metabolic labeling experiments further confirmed that TBEVC and other flaviviral capsid proteins are able to induce translational shutoff and decrease of 18S rRNA. These findings may substantially help to design a targeted therapy against TBEV.
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3
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Li Q, Kang C. Structures and Dynamics of Dengue Virus Nonstructural Membrane Proteins. MEMBRANES 2022; 12:231. [PMID: 35207152 PMCID: PMC8880049 DOI: 10.3390/membranes12020231] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Revised: 02/11/2022] [Accepted: 02/15/2022] [Indexed: 02/01/2023]
Abstract
Dengue virus is an important human pathogen threating people, especially in tropical and sub-tropical regions. The viral genome has one open reading frame and encodes one polyprotein which can be processed into structural and nonstructural (NS) proteins. Four of the seven nonstructural proteins, NS2A, NS2B, NS4A and NS4B, are membrane proteins. Unlike NS3 or NS5, these proteins do not harbor any enzymatic activities, but they play important roles in viral replication through interactions with viral or host proteins to regulate important pathways and enzymatic activities. The location of these proteins on the cell membrane and the functional roles in viral replication make them important targets for antiviral development. Indeed, NS4B inhibitors exhibit antiviral activities in different assays. Structural studies of these proteins are hindered due to challenges in crystallization and the dynamic nature of these proteins. In this review, the function and membrane topologies of dengue nonstructural membrane proteins are presented. The roles of solution NMR spectroscopy in elucidating the structure and dynamics of these proteins are introduced. The success in the development of NS4B inhibitors proves that this class of proteins is an attractive target for antiviral development.
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Affiliation(s)
- Qingxin Li
- Guangdong Provincial Engineering Laboratory of Biomass High Value Utilization, Institute of Biological and Medical Engineering, Guangdong Academy of Sciences, Guangzhou 510316, China
| | - Congbao Kang
- Experimental Drug Development Centre, Agency for Science, Technology and Research, 10 Biopolis Road, #5-01, Singapore 138670, Singapore
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INMI1 Zika Virus NS4B Antagonizes the Interferon Signaling by Suppressing STAT1 Phosphorylation. Viruses 2021; 13:v13122448. [PMID: 34960717 PMCID: PMC8705506 DOI: 10.3390/v13122448] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 11/22/2021] [Accepted: 12/02/2021] [Indexed: 12/17/2022] Open
Abstract
The evasion of the Interferon response has important implications in Zika virus (ZIKV) disease. Mutations in ZIKV viral protein NS4B, associated with modulation of the interferon (IFN) system, have been linked to increased pathogenicity in animal models. In this study, we unravel ZIKV NS4B as antagonist of the IFN signaling cascade. Firstly, we reported the genomic characterization of NS4B isolated from a strain of the 2016 outbreak, ZIKV Brazil/2016/INMI1, and we predicted its membrane topology. Secondly, we analyzed its phylogenetic correlation with other flaviviruses, finding a high similarity with dengue virus 2 (DEN2) strains; in particular, the highest conservation was found when NS4B was aligned with the IFN inhibitory domain of DEN2 NS4B. Hence, we asked whether ZIKV NS4B was also able to inhibit the IFN signaling cascade, as reported for DEN2 NS4B. Our results showed that ZIKV NS4B was able to strongly inhibit the IFN stimulated response element and the IFN-γ-activated site transcription, blocking IFN-I/-II responses. mRNA expression levels of the IFN stimulated genes ISG15 and OAS1 were also strongly reduced in presence of NS4B. We found that the viral protein was acting by suppressing the STAT1 phosphorylation and consequently blocking the nuclear transport of both STAT1 and STAT2.
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5
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Sharma KB, Vrati S, Kalia M. Pathobiology of Japanese encephalitis virus infection. Mol Aspects Med 2021; 81:100994. [PMID: 34274157 DOI: 10.1016/j.mam.2021.100994] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Revised: 07/13/2021] [Accepted: 07/13/2021] [Indexed: 12/25/2022]
Abstract
Japanese encephalitis virus (JEV) is a flavivirus, spread by the bite of carrier Culex mosquitoes. The subsequent disease caused is Japanese encephalitis (JE), which is the leading global cause of virus-induced encephalitis. The disease is predominant in the entire Asia-Pacific region with the potential of global spread. JEV is highly neuroinvasive with symptoms ranging from mild fever to severe encephalitis and death. One-third of JE infections are fatal, and half of the survivors develop permanent neurological sequelae. Disease prognosis is determined by a series of complex and intertwined signaling events dictated both by the virus and the host. All flaviviruses, including JEV replicate in close association with ER derived membranes by channelizing the protein and lipid components of the ER. This leads to activation of acute stress responses in the infected cell-oxidative stress, ER stress, and autophagy. The host innate immune and inflammatory responses also enter the fray, the components of which are inextricably linked to the cellular stress responses. These are especially crucial in the periphery for dendritic cell maturation and establishment of adaptive immunity. The pathogenesis of JEV is a combination of direct virus induced neuronal cell death and an uncontrolled neuroinflammatory response. Here we provide a comprehensive review of the JEV life cycle and how the cellular stress responses dictate the pathobiology and resulting immune response. We also deliberate on how modulation of these stress pathways could be a potential strategy to develop therapeutic interventions, and define the persisting challenges.
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Affiliation(s)
- Kiran Bala Sharma
- Virology Research Group, Regional Centre for Biotechnology, NCR Biotech Science Cluster, Faridabad, India
| | - Sudhanshu Vrati
- Virology Research Group, Regional Centre for Biotechnology, NCR Biotech Science Cluster, Faridabad, India.
| | - Manjula Kalia
- Virology Research Group, Regional Centre for Biotechnology, NCR Biotech Science Cluster, Faridabad, India.
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6
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Mikulasova A, Gillespie LK, Ambrose RL, Aktepe TE, Trenerry AM, Liebscher S, Mackenzie JM. A Putative Lipid-Associating Motif in the West Nile Virus NS4A Protein Is Required for Efficient Virus Replication. Front Cell Dev Biol 2021; 9:655606. [PMID: 34055786 PMCID: PMC8149610 DOI: 10.3389/fcell.2021.655606] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Accepted: 04/07/2021] [Indexed: 01/06/2023] Open
Abstract
Flavivirus replication is intimately associated with re-organized cellular membranes. These virus-induced changes in membrane architecture form three distinct membranous “organelles” that have specific functions during the flavivirus life cycle. One of these structures is the replication complex in which the flaviviral RNA is replicated to produce progeny genomes. We have previously observed that this process is strictly dependent on cellular cholesterol. In this study we have identified a putative cholesterol recognition/interaction amino acid consensus (CRAC) motif within the West Nile virus strain Kunjin virus (WNVKUN) NS4A protein. Site-directed mutagenesis of this motif within a WNVKUN infectious clone severely attenuated virus replication and the capacity of the mutant viruses to form the replication complex. Replication of the mutant viruses also displayed reduced co-localization with cellular markers recruited to replication sites during wild-type virus replication. In addition, we observed that the mutant viruses were significantly impaired in their ability to remodel cytoplasmic membranes. However, after extensive analysis we are unable to conclusively reveal a role for the CRAC motif in direct cholesterol binding to NS4A, suggesting additional complex lipid-protein and protein-protein interactions. We believe this study highlights the crucial role for this region within NS4A protein in recruitment of cellular and viral proteins to specialized subdomains on membrane platforms to promote efficient virus replication.
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Affiliation(s)
- Andrea Mikulasova
- Department of Physiology Anatomy and Microbiology, La Trobe University, Melbourne, VIC, Australia
| | - Leah K Gillespie
- Department of Microbiology and Immunology, University of Melbourne, Melbourne, VIC, Australia
| | - Rebecca L Ambrose
- Department of Microbiology and Immunology, University of Melbourne, Melbourne, VIC, Australia
| | - Turgut E Aktepe
- Department of Microbiology and Immunology, University of Melbourne, Melbourne, VIC, Australia
| | - Alice M Trenerry
- Department of Microbiology and Immunology, University of Melbourne, Melbourne, VIC, Australia
| | - Susann Liebscher
- Department of Microbiology and Immunology, University of Melbourne, Melbourne, VIC, Australia
| | - Jason M Mackenzie
- Department of Microbiology and Immunology, University of Melbourne, Melbourne, VIC, Australia
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7
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Sarkar R, Sharma KB, Kumari A, Asthana S, Kalia M. Japanese encephalitis virus capsid protein interacts with non-lipidated MAP1LC3 on replication membranes and lipid droplets. J Gen Virol 2021; 102. [DOI: 10.1099/jgv.0.001508] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Microtubule-associated protein 1 light chain 3 (MAP1LC3) is a protein with a well-defined function in autophagy, but still incompletely understood roles in several other autophagy-independent processess. Studies have shown MAP1LC3 is a host-dependency factor for the replication of several viruses. Japanese encephalitis virus (JEV), a neurotropic flavivirus, replicates on ER-derived membranes that are marked by autophagosome-negative non-lipidated MAP1LC3 (LC3-I). Depletion of LC3 exerts a profound inhibition on virus replication and egress. Here, we further characterize the role of LC3 in JEV replication, and through immunofluorescence and immunoprecipitation show that LC3-I interacts with the virus capsid protein in infected cells. This association was observed on capsid localized to both the replication complex and lipid droplets (LDs). JEV infection decreased the number of LDs per cell indicating a link between lipid metabolism and virus replication. This capsid-LC3 interaction was independent of the autophagy adaptor protein p62/Sequestosome 1 (SQSTM1). Further, no association of capsid was seen with the Gamma-aminobutyric acid receptor-associated protein family, suggesting that this interaction was specific for LC3. High-resolution protein-protein docking studies identified a putative LC3-interacting region in capsid, 56FTAL59,
and other key residues that could mediate a direct interaction between the two proteins.
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Affiliation(s)
- Riya Sarkar
- Translational Health Science & Technology Institute, NCR Biotech Science Cluster, Faridabad, Haryana, India
| | - Kiran Bala Sharma
- Regional Centre for Biotechnology, NCR Biotech Science Cluster, Faridabad, Haryana, India
- Translational Health Science & Technology Institute, NCR Biotech Science Cluster, Faridabad, Haryana, India
| | - Anita Kumari
- Translational Health Science & Technology Institute, NCR Biotech Science Cluster, Faridabad, Haryana, India
| | - Shailendra Asthana
- Translational Health Science & Technology Institute, NCR Biotech Science Cluster, Faridabad, Haryana, India
| | - Manjula Kalia
- Translational Health Science & Technology Institute, NCR Biotech Science Cluster, Faridabad, Haryana, India
- Regional Centre for Biotechnology, NCR Biotech Science Cluster, Faridabad, Haryana, India
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8
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Abstract
The flavivirus genus encompasses more than 75 unique viruses, including dengue virus which accounts for almost 390 million global infections annually. Flavivirus infection can result in a myriad of symptoms ranging from mild rash and flu-like symptoms, to severe encephalitis and even hemorrhagic fever. Efforts to combat the impact of these viruses have been hindered due to limited antiviral drug and vaccine development. However, the advancement of knowledge in the structural biology of flaviviruses over the last 25 years has produced unique perspectives for the identification of potential therapeutic targets. With particular emphasis on the assembly and maturation stages of the flavivirus life cycle, it is the goal of this review to comparatively analyze the structural similarities between flaviviruses to provide avenues for new research and innovation.
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Affiliation(s)
- Conrrad M R Nicholls
- Department of Biological Sciences, Purdue University, West Lafayette, IN, United States
| | - Madhumati Sevvana
- Department of Biological Sciences, Purdue University, West Lafayette, IN, United States
| | - Richard J Kuhn
- Department of Biological Sciences, Purdue University, West Lafayette, IN, United States; Purdue Institute of Inflammation, Immunology, and Infectious Disease, Purdue University, West Lafayette, IN, United States.
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9
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Kaufusi PH, Tseng AC, Kelley JF, Nerurkar VR. Selective Reactivity of Anti-Japanese Encephalitis Virus NS4B Antibody Towards Different Flaviviruses. Viruses 2020; 12:E212. [PMID: 32075019 PMCID: PMC7077296 DOI: 10.3390/v12020212] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2020] [Revised: 02/03/2020] [Accepted: 02/11/2020] [Indexed: 01/23/2023] Open
Abstract
Studies investigating West Nile virus (WNV) NS4B protein function are hindered by the lack of an antibody recognizing WNV NS4B protein. Few laboratories have produced WNV NS4B antibodies, and none have been shown to work consistently. In this report, we describe a NS4B antibody against Japanese encephalitis virus (JEV) NS4B protein that cross-reacts with the NS4B protein of WNV but not of dengue virus (DENV). This JEV NS4B antibody not only recognizes WNV NS4B in infected cells, but also recognizes the NS4B protein expressed using transfection. It is evident from this data that the JEV NS4B antibody is specific to NS4B of WNV but not to NS4B of the four DENV serotypes. The specificity of this antibody may be due to the notable differences that exist between the amino acid sequence identity and antigenic relationships within the NS4B protein of the WNV, DENV, and JEV.
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Affiliation(s)
- Pakieli H. Kaufusi
- Department of Tropical Medicine, Medical Microbiology and Pharmacology, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, HI 96813, USA; (A.C.T.); (J.F.K.)
- Pacific Center for Emerging Infectious Diseases Research, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, HI 96813, USA
- Department of Molecular Biosciences and Bioengineering, College of Tropical Agriculture and Human Resources, University of Hawaii at Manoa, Honolulu, HI 96822, USA
| | - Alanna C. Tseng
- Department of Tropical Medicine, Medical Microbiology and Pharmacology, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, HI 96813, USA; (A.C.T.); (J.F.K.)
- Department of Molecular Biosciences and Bioengineering, College of Tropical Agriculture and Human Resources, University of Hawaii at Manoa, Honolulu, HI 96822, USA
| | - James F. Kelley
- Department of Tropical Medicine, Medical Microbiology and Pharmacology, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, HI 96813, USA; (A.C.T.); (J.F.K.)
- Pacific Center for Emerging Infectious Diseases Research, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, HI 96813, USA
- World Health Organization of the Western Pacific Region, Malaria, Other Vector-borne and Parasitic Diseases Unit, United Nations Ave, Ermita, Manila, 1000 Metro Manila, Philippines
| | - Vivek R. Nerurkar
- Department of Tropical Medicine, Medical Microbiology and Pharmacology, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, HI 96813, USA; (A.C.T.); (J.F.K.)
- Pacific Center for Emerging Infectious Diseases Research, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, HI 96813, USA
- Department of Molecular Biosciences and Bioengineering, College of Tropical Agriculture and Human Resources, University of Hawaii at Manoa, Honolulu, HI 96822, USA
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10
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Rana J, Burrone OR. DENV2 Pseudoviral Particles with Unprocessed Capsid Protein Are Assembled and Infectious. Viruses 2019; 12:v12010027. [PMID: 31881703 PMCID: PMC7019998 DOI: 10.3390/v12010027] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Revised: 12/06/2019] [Accepted: 12/23/2019] [Indexed: 11/16/2022] Open
Abstract
Proteolytic processing of flavivirus polyprotein is a uniquely controlled process. To date, the sequential cleavage of the capsid anchor sequence at the junction of C-PrM has been considered essential for the production of flaviviruses. In this study, we used two experimental approaches to show the effect of unprocessed capsid on the production and infectivity of dengue virus 2 (DENV2) pseudoviral particles. The results showed that (1) both mature and unprocessed capsids of DENV2 were equally efficient in the viral RNA packaging and also in the assembly of infective particles; (2) DENV2 variants, in which the viral and host mediated cleavage of Ca peptide were independent, produced significantly higher levels of infective particles. Overall, this study demonstrated that unlike other flaviviruses, DENV2 capsid does not require a cleavable Ca sequence, and the sequential cleavage is not an obligatory requirement for the morphogenesis of infective pseudoviral particles.
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Affiliation(s)
- Jyoti Rana
- Correspondence: (J.R.); (O.R.B.); Tel.: +39-040-3757314 (J.R. & O.R.B.)
| | - Oscar R. Burrone
- Correspondence: (J.R.); (O.R.B.); Tel.: +39-040-3757314 (J.R. & O.R.B.)
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11
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Lazo L, Valdes I, Guillén G, Hermida L, Gil L. Aiming at the heart: the capsid protein of dengue virus as a vaccine candidate. Expert Rev Vaccines 2019; 18:161-173. [PMID: 30677305 DOI: 10.1080/14760584.2019.1574575] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
INTRODUCTION Dengue fever remains as a health problem worldwide. Although Dengvaxia®, was registered in several countries, the results after the immunization of people suggest an increase of risk in non-immune persons and children younger than 9 years old. No other vaccine is registered so far, thus the development of a safe and effective vaccine continues to be a priority for the WHO and the scientific community. AREAS COVERED This work reviews the structural and antigenic properties of the capsid protein of Dengue virus, along with results of studies performed to assess the immunogenicity and protective capacity in animals of vaccine candidates based on this protein. EXPERT OPINION The generation of a memory cellular immune response alone, after vaccination against Dengue virus, could be advantageous, as there would not be risk of increasing viral infectivity through sub-neutralizing antibodies. However, it is improbable to achieving sterilizing immunity. In this scenario, an infection could stablished but without the appearance of the severe disease. The cell-mediated immunity should keep the virus at bay. The capsid protein induces a protective immune response in animals without the induction of virus-binding antibodies. Vaccine candidates based on this protein could be an attractive strategy to induce protection against the severe Dengue disease.
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Affiliation(s)
- Laura Lazo
- a Vaccine Department , Center for Genetic Engineering and Biotechnology (CIGB) , Havana , Cuba
| | - Iris Valdes
- a Vaccine Department , Center for Genetic Engineering and Biotechnology (CIGB) , Havana , Cuba
| | - Gerardo Guillén
- a Vaccine Department , Center for Genetic Engineering and Biotechnology (CIGB) , Havana , Cuba
| | - Lisset Hermida
- a Vaccine Department , Center for Genetic Engineering and Biotechnology (CIGB) , Havana , Cuba
| | - Lázaro Gil
- a Vaccine Department , Center for Genetic Engineering and Biotechnology (CIGB) , Havana , Cuba
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12
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Lopez-Denman AJ, Russo A, Wagstaff KM, White PA, Jans DA, Mackenzie JM. Nucleocytoplasmic shuttling of the West Nile virus RNA-dependent RNA polymerase NS5 is critical to infection. Cell Microbiol 2018; 20:e12848. [PMID: 29582535 DOI: 10.1111/cmi.12848] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Revised: 03/08/2018] [Accepted: 03/16/2018] [Indexed: 01/05/2023]
Abstract
West Nile virus (WNV) is a single-stranded, positive sense RNA virus of the family Flaviviridae and is a significant pathogen of global medical importance. Flavivirus replication is known to be exclusively cytoplasmic, but we show here for the first time that access to the nucleus of the WNV strain Kunjin (WNVKUN ) RNA-dependent RNA polymerase (protein NS5) is central to WNVKUN virus production. We show that treatment of cells with the specific nuclear export inhibitor leptomycin B (LMB) results in increased NS5 nuclear accumulation in WNVKUN -infected cells and NS5-transfected cells, indicative of nucleocytoplasmic shuttling under normal conditions. We used site-directed mutagenesis to identify the nuclear localisation sequence (NLS) responsible for WNVKUN NS5 nuclear targeting, observing that mutation of this NLS resulted in exclusively cytoplasmic accumulation of NS5 even in the presence of leptomycin B. Introduction of NS5 NLS mutations into FLSDX, an infectious clone of WNVKUN , resulted in lethality, suggesting that the ability of NS5 to traffic into the nucleus in integral to WNVKUN replication. This study thus shows for the first time that NLS-dependent trafficking into the nucleus during infection of WNVKUN NS5 is critical for viral replication. Excitingly, specific inhibitors of NS5 nuclear import reduce WNVKUN virus production, proving the principle that inhibition of WNVKUN NS5 nuclear import is a viable therapeutic avenue for antiviral drug development in the future.
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Affiliation(s)
- Adam J Lopez-Denman
- Department of Microbiology and Immunology, Peter Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, Victoria, Australia.,Department of Physiology, Anatomy and Microbiology, La Trobe University, Melbourne, Victoria, Australia
| | - Alice Russo
- Faculty of Science, Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, New South Wales, Australia
| | - Kylie M Wagstaff
- Department of Biochemistry, Monash University, Melbourne, Victoria, Australia
| | - Peter A White
- Faculty of Science, Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, New South Wales, Australia
| | - David A Jans
- Department of Biochemistry, Monash University, Melbourne, Victoria, Australia
| | - Jason M Mackenzie
- Department of Microbiology and Immunology, Peter Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, Victoria, Australia
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13
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Shang Z, Song H, Shi Y, Qi J, Gao GF. Crystal Structure of the Capsid Protein from Zika Virus. J Mol Biol 2018; 430:948-962. [DOI: 10.1016/j.jmb.2018.02.006] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Revised: 01/31/2018] [Accepted: 02/09/2018] [Indexed: 12/27/2022]
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14
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Phanthanawiboon S, Pambudi S, Omokoko MD, Hanabara K, A-Nuegoonpipat A, Kamitani W, Ikuta K, Kurosu T. Construction of a high-yield dengue virus by replacing nonstructural proteins 3-4B without increasing virulence. Biochem Biophys Res Commun 2017; 495:1221-1226. [PMID: 29175328 DOI: 10.1016/j.bbrc.2017.11.137] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Accepted: 11/20/2017] [Indexed: 11/20/2022]
Abstract
Producing virus at high yield is critically important for development of whole virion inactivated vaccines or live attenuated vaccines. Most dengue virus (DENV) clinical isolates, however, replicate at low levels in cultured cells, which limits their use for vaccine development. The present study examined differences between low-replicating DENV clinical isolates and high-replicating laboratory strains with the aim of engineering high-yield DENV clinical isolates. Construction of a series of recombinant chimeric viruses derived from a high-replicating laboratory DENV type 4 (DENV-4) H241 strain and a clinical isolate revealed that the NS3-NS4B region of H241 conferred a replication advantage in cultured cells. Furthermore, northern blot analysis revealed that this advantage was due to more efficient synthesis of viral RNA. Importantly, replacement of the NS3-NS4B region of H241 did not increase virulence in mice, suggesting that viral production can be increased safely. This study provided information that will facilitate engineering of safe and high-yield viruses that can be used for vaccine development.
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Affiliation(s)
- Supranee Phanthanawiboon
- Research Institute for Microbial Diseases, Osaka University, 3-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Sabar Pambudi
- Research Institute for Microbial Diseases, Osaka University, 3-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Magot Diata Omokoko
- Research Institute for Microbial Diseases, Osaka University, 3-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Keiko Hanabara
- Research Institute for Microbial Diseases, Osaka University, 3-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | | | - Wataru Kamitani
- Research Institute for Microbial Diseases, Osaka University, 3-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Kazuyoshi Ikuta
- Research Institute for Microbial Diseases, Osaka University, 3-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Takeshi Kurosu
- Research Institute for Microbial Diseases, Osaka University, 3-1 Yamadaoka, Suita, Osaka 565-0871, Japan.
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15
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Lopez-Denman AJ, Mackenzie JM. The IMPORTance of the Nucleus during Flavivirus Replication. Viruses 2017; 9:v9010014. [PMID: 28106839 PMCID: PMC5294983 DOI: 10.3390/v9010014] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Revised: 01/10/2017] [Accepted: 01/12/2017] [Indexed: 12/24/2022] Open
Abstract
Flaviviruses are a large group of arboviruses of significant medical concern worldwide. With outbreaks a common occurrence, the need for efficient viral control is required more than ever. It is well understood that flaviviruses modulate the composition and structure of membranes in the cytoplasm that are crucial for efficient replication and evading immune detection. As the flavivirus genome consists of positive sense RNA, replication can occur wholly within the cytoplasm. What is becoming more evident is that some viral proteins also have the ability to translocate to the nucleus, with potential roles in replication and immune system perturbation. In this review, we discuss the current understanding of flavivirus nuclear localisation, and the function it has during flavivirus infection. We also describe-while closely related-the functional differences between similar viral proteins in their nuclear translocation.
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Affiliation(s)
- Adam J Lopez-Denman
- Department of Microbiology & Immunology, Peter Doherty Institute for Infection and Immunity, University of Melbourne, Victoria 3010, Australia.
- Department of Physiology, Anatomy & Microbiology, La Trobe University, Melbourne 3086, Australia.
| | - Jason M Mackenzie
- Department of Microbiology & Immunology, Peter Doherty Institute for Infection and Immunity, University of Melbourne, Victoria 3010, Australia.
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16
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The flavivirus capsid protein: Structure, function and perspectives towards drug design. Virus Res 2017; 227:115-123. [DOI: 10.1016/j.virusres.2016.10.005] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Revised: 09/29/2016] [Accepted: 10/12/2016] [Indexed: 12/12/2022]
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17
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Miyamura T, Lemon SM, Walker CM, Wakita T. The HCV Replicase Complex and Viral RNA Synthesis. HEPATITIS C VIRUS I 2016. [PMCID: PMC7122888 DOI: 10.1007/978-4-431-56098-2_8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Replication of hepatitis C virus (HCV) is tightly linked to membrane alterations designated the membranous web, harboring the viral replicase complex. In this chapter we describe the morphology and 3D architecture of the HCV-induced replication organelles, mainly consisting of double membrane vesicles, which are generated by a concerted action of the nonstructural proteins NS3 to NS5B. Recent studies have furthermore identified a number of host cell proteins and lipids contributing to the biogenesis of the membranous web, which are discussed in this chapter. Viral RNA synthesis is tightly associated with these membrane alterations and mainly driven by the viral RNA dependent RNA polymerase NS5B. We summarize our current knowledge of the structure and function of NS5B, the role of cis-acting replication elements at the termini of the genome in regulating RNA synthesis and the contribution of additional viral and host factors to viral RNA synthesis, which is still ill defined.
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Affiliation(s)
- Tatsuo Miyamura
- National Institute of Infectious Diseases, Tokyo, Tokyo Japan
| | - Stanley M. Lemon
- Departments of Medicine and Microbiology & Immunology , The University of North Carolina, Chapel Hill, North Carolina USA
| | - Christopher M. Walker
- Center for Vaccines and Immunity, The Research Institute at Nationwide Children's Hospital, Columbus, Ohio USA
| | - Takaji Wakita
- National Institute of Infectious Diseases, Tokyo, Tokyo Japan
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18
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Abstract
Dengue virus affects hundreds of millions of people each year around the world, causing a tremendous social and economic impact on affected countries. The aim of this review is to summarize our current knowledge of the functions, structure, and interactions of the viral capsid protein. The primary role of capsid is to package the viral genome. There are two processes linked to this function: the recruitment of the viral RNA during assembly and the release of the genome during infection. Although particle assembly takes place on endoplasmic reticulum membranes, capsid localizes in nucleoli and lipid droplets. Why capsid accumulates in these locations during infection remains unknown. In this review, we describe available data and discuss new ideas on dengue virus capsid functions and interactions. We believe that a deeper understanding of how the capsid protein works during infection will create opportunities for novel antiviral strategies, which are urgently needed to control dengue virus infections.
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Affiliation(s)
- Laura A Byk
- Fundación Instituto Leloir-National Research Council for Science and Technology (CONICET), Buenos Aires 1405, Argentina;
| | - Andrea V Gamarnik
- Fundación Instituto Leloir-National Research Council for Science and Technology (CONICET), Buenos Aires 1405, Argentina;
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19
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Endoplasmic Reticulum: The Favorite Intracellular Niche for Viral Replication and Assembly. Viruses 2016; 8:v8060160. [PMID: 27338443 PMCID: PMC4926180 DOI: 10.3390/v8060160] [Citation(s) in RCA: 122] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2016] [Revised: 05/23/2016] [Accepted: 05/26/2016] [Indexed: 02/07/2023] Open
Abstract
The endoplasmic reticulum (ER) is the largest intracellular organelle. It forms a complex network of continuous sheets and tubules, extending from the nuclear envelope (NE) to the plasma membrane. This network is frequently perturbed by positive-strand RNA viruses utilizing the ER to create membranous replication factories (RFs), where amplification of their genomes occurs. In addition, many enveloped viruses assemble progeny virions in association with ER membranes, and viruses replicating in the nucleus need to overcome the NE barrier, requiring transient changes of the NE morphology. This review first summarizes some key aspects of ER morphology and then focuses on the exploitation of the ER by viruses for the sake of promoting the different steps of their replication cycles.
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20
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Zhu Z, Chan JFW, Tee KM, Choi GKY, Lau SKP, Woo PCY, Tse H, Yuen KY. Comparative genomic analysis of pre-epidemic and epidemic Zika virus strains for virological factors potentially associated with the rapidly expanding epidemic. Emerg Microbes Infect 2016; 5:e22. [PMID: 26980239 PMCID: PMC4820678 DOI: 10.1038/emi.2016.48] [Citation(s) in RCA: 142] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Accepted: 03/03/2016] [Indexed: 12/21/2022]
Abstract
Less than 20 sporadic cases of human Zika virus (ZIKV) infection were reported in Africa and Asia before 2007, but large outbreaks involving up to 73% of the populations on the Pacific islands have started since 2007, and spread to the Americas in 2014. Moreover, the clinical manifestation of ZIKV infection has apparently changed, as evident by increasing reports of neurological complications, such as Guillain-Barré syndrome in adults and congenital anomalies in neonates. We comprehensively compared the genome sequences of pre-epidemic and epidemic ZIKV strains with complete genome or complete polyprotein sequences available in GenBank. Besides the reported phylogenetic clustering of the epidemic strains with the Asian lineage, we found that the topology of phylogenetic tree of all coding regions is the same except that of the non-structural 2B (NS2B) coding region. This finding was confirmed by bootscan analysis and multiple sequence alignment, which suggested the presence of a fragment of genetic recombination at NS2B with that of Spondweni virus. Moreover, the representative epidemic strain possesses one large bulge of nine bases instead of an external loop on the first stem-loop structure at the 3'-untranslated region just distal to the stop codon of the NS5 in the 1947 pre-epidemic prototype strain. Fifteen amino acid substitutions are found in the epidemic strains when compared with the pre-epidemic strains. As mutations in other flaviviruses can be associated with changes in virulence, replication efficiency, antigenic epitopes and host tropism, further studies would be important to ascertain the biological significance of these genomic changes.
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Affiliation(s)
- Zheng Zhu
- Department of Microbiology, The University of Hong Kong, Hong Kong, China
| | - Jasper Fuk-Woo Chan
- Department of Microbiology, The University of Hong Kong, Hong Kong, China
- State Key Laboratory of Emerging Infectious Diseases, The University of Hong Kong, Hong Kong, China
- Research Centre of Infection and Immunology, The University of Hong Kong, Hong Kong, China
- Carol Yu Centre for Infection, The University of Hong Kong, Hong Kong, China
| | - Kah-Meng Tee
- Department of Microbiology, The University of Hong Kong, Hong Kong, China
| | - Garnet Kwan-Yue Choi
- Research Centre of Infection and Immunology, The University of Hong Kong, Hong Kong, China
| | - Susanna Kar-Pui Lau
- Department of Microbiology, The University of Hong Kong, Hong Kong, China
- State Key Laboratory of Emerging Infectious Diseases, The University of Hong Kong, Hong Kong, China
- Research Centre of Infection and Immunology, The University of Hong Kong, Hong Kong, China
- Carol Yu Centre for Infection, The University of Hong Kong, Hong Kong, China
| | - Patrick Chiu-Yat Woo
- Department of Microbiology, The University of Hong Kong, Hong Kong, China
- State Key Laboratory of Emerging Infectious Diseases, The University of Hong Kong, Hong Kong, China
- Research Centre of Infection and Immunology, The University of Hong Kong, Hong Kong, China
- Carol Yu Centre for Infection, The University of Hong Kong, Hong Kong, China
| | - Herman Tse
- Department of Microbiology, The University of Hong Kong, Hong Kong, China
- State Key Laboratory of Emerging Infectious Diseases, The University of Hong Kong, Hong Kong, China
- Research Centre of Infection and Immunology, The University of Hong Kong, Hong Kong, China
- Carol Yu Centre for Infection, The University of Hong Kong, Hong Kong, China
| | - Kwok-Yung Yuen
- Department of Microbiology, The University of Hong Kong, Hong Kong, China
- State Key Laboratory of Emerging Infectious Diseases, The University of Hong Kong, Hong Kong, China
- Research Centre of Infection and Immunology, The University of Hong Kong, Hong Kong, China
- Carol Yu Centre for Infection, The University of Hong Kong, Hong Kong, China
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21
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Li Y, Kim YM, Zou J, Wang QY, Gayen S, Wong YL, Lee LT, Xie X, Huang Q, Lescar J, Shi PY, Kang C. Secondary structure and membrane topology of dengue virus NS4B N-terminal 125 amino acids. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2015; 1848:3150-7. [DOI: 10.1016/j.bbamem.2015.09.016] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Revised: 08/22/2015] [Accepted: 09/18/2015] [Indexed: 12/24/2022]
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22
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Guiding dengue vaccine development using knowledge gained from the success of the yellow fever vaccine. Cell Mol Immunol 2015; 13:36-46. [PMID: 26435066 DOI: 10.1038/cmi.2015.76] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2015] [Revised: 06/15/2015] [Accepted: 07/14/2015] [Indexed: 12/30/2022] Open
Abstract
Flaviviruses comprise approximately 70 closely related RNA viruses. These include several mosquito-borne pathogens, such as yellow fever virus (YFV), dengue virus (DENV), and Japanese encephalitis virus (JEV), which can cause significant human diseases and thus are of great medical importance. Vaccines against both YFV and JEV have been used successfully in humans for decades; however, the development of a DENV vaccine has encountered considerable obstacles. Here, we review the protective immune responses elicited by the vaccine against YFV to provide some insights into the development of a protective DENV vaccine.
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23
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Stock N, Escadafal C, Achazi K, Cissé M, Niedrig M. Development and characterization of polyclonal peptide antibodies for the detection of Yellow fever virus proteins. J Virol Methods 2015; 222:110-6. [DOI: 10.1016/j.jviromet.2015.06.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2014] [Revised: 05/28/2015] [Accepted: 06/10/2015] [Indexed: 01/08/2023]
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24
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Abstract
Dengue virus (DENV) is an important human pathogen causing millions of disease cases and thousands of deaths worldwide. Non-structural protein 4A (NS4A) is a vital component of the viral replication complex (RC) and plays a major role in the formation of host cell membrane-derived structures that provide a scaffold for replication. The N-terminal cytoplasmic region of NS4A(1–48) is known to preferentially interact with highly curved membranes. Here, we provide experimental evidence for the stable binding of NS4A(1–48) to small liposomes using a liposome floatation assay and identify the lipid binding sequence by NMR spectroscopy. Mutations L6E;M10E were previously shown to inhibit DENV replication and to interfere with the binding of NS4A(1–48) to small liposomes. Our results provide new details on the interaction of the N-terminal region of NS4A with membranes and will prompt studies of the functional relevance of the curvature sensitive membrane anchor at the N-terminus of NS4A.
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25
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Zmurko J, Neyts J, Dallmeier K. Flaviviral NS4b, chameleon and jack-in-the-box roles in viral replication and pathogenesis, and a molecular target for antiviral intervention. Rev Med Virol 2015; 25:205-23. [PMID: 25828437 PMCID: PMC4864441 DOI: 10.1002/rmv.1835] [Citation(s) in RCA: 77] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Revised: 02/16/2015] [Accepted: 02/17/2015] [Indexed: 12/27/2022]
Abstract
Dengue virus and other flaviviruses such as the yellow fever, West Nile, and Japanese encephalitis viruses are emerging vector-borne human pathogens that affect annually more than 100 million individuals and that may cause debilitating and potentially fatal hemorrhagic and encephalitic diseases. Currently, there are no specific antiviral drugs for the treatment of flavivirus-associated disease. A better understanding of the flavivirus-host interactions during the different events of the flaviviral life cycle may be essential when developing novel antiviral strategies. The flaviviral non-structural protein 4b (NS4b) appears to play an important role in flaviviral replication by facilitating the formation of the viral replication complexes and in counteracting innate immune responses such as the following: (i) type I IFN signaling; (ii) RNA interference; (iii) formation of stress granules; and (iv) the unfolded protein response. Intriguingly, NS4b has recently been shown to constitute an excellent target for the selective inhibition of flavivirus replication. We here review the current knowledge on NS4b.
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Affiliation(s)
- Joanna Zmurko
- KU Leuven, Rega Institute for Medical Research, Department of Microbiology and Immunology, Laboratory of Virology and Chemotherapy
| | - Johan Neyts
- KU Leuven, Rega Institute for Medical Research, Department of Microbiology and Immunology, Laboratory of Virology and Chemotherapy
| | - Kai Dallmeier
- KU Leuven, Rega Institute for Medical Research, Department of Microbiology and Immunology, Laboratory of Virology and Chemotherapy
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26
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Xie X, Zou J, Wang QY, Shi PY. Targeting dengue virus NS4B protein for drug discovery. Antiviral Res 2015; 118:39-45. [DOI: 10.1016/j.antiviral.2015.03.007] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2015] [Revised: 03/06/2015] [Accepted: 03/13/2015] [Indexed: 10/23/2022]
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27
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Kim JK, Kim JM, Song BH, Yun SI, Yun GN, Byun SJ, Lee YM. Profiling of viral proteins expressed from the genomic RNA of Japanese encephalitis virus using a panel of 15 region-specific polyclonal rabbit antisera: implications for viral gene expression. PLoS One 2015; 10:e0124318. [PMID: 25915765 PMCID: PMC4410938 DOI: 10.1371/journal.pone.0124318] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2015] [Accepted: 02/27/2015] [Indexed: 12/16/2022] Open
Abstract
Japanese encephalitis virus (JEV), a mosquito-borne flavivirus, is closely related to West Nile (WN), yellow fever (YF), and dengue (DEN) viruses. Its plus-strand genomic RNA carries a single open reading frame encoding a polyprotein that is cleaved into three structural (C, prM/M, and E) and at least seven nonstructural (NS1/NS1', NS2A, NS2B, NS3, NS4A, NS4B, and NS5) proteins, based on previous work with WNV, YFV, and DENV. Here, we aimed to profile experimentally all the viral proteins found in JEV-infected cells. We generated a collection of 15 JEV-specific polyclonal antisera covering all parts of the viral protein-coding regions, by immunizing rabbits with 14 bacterially expressed glutathione-S-transferase fusion proteins (for all nine viral proteins except NS2B) or with a chemically synthesized oligopeptide (for NS2B). In total lysates of JEV-infected BHK-21 cells, immunoblotting with these antisera revealed: (i) three mature structural proteins (~12-kDa C, ~8-kDa M, and ~53-kDa E), a precursor of M (~24-kDa prM) and three other M-related proteins (~10-14 kDa); (ii) the predicted ~45-kDa NS1 and its frameshift product, ~58-kDa NS1', with no evidence of the predicted ~25-kDa NS2A; (iii) the predicted but hardly detectable ~14-kDa NS2B and an unexpected but predominant ~12-kDa NS2B-related protein; (iv) the predicted ~69-kDa NS3 plus two major cleavage products (~34-kDa NS3N-term and ~35-kDa NS3C-term), together with at least nine minor proteins of ~16-52 kDa; (v) the predicted ~14-kDa NS4A; (vi) two NS4B-related proteins (~27-kDa NS4B and ~25-kDa NS4B'); and (vii) the predicted ~103-kDa NS5 plus at least three other NS5-related proteins (~15 kDa, ~27 kDa, and ~90 kDa). Combining these data with confocal microscopic imaging of the proteins' intracellular localization, our study is the first to provide a solid foundation for the study of JEV gene expression, which is crucial for elucidating the regulatory mechanisms of JEV genome replication and pathobiology.
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Affiliation(s)
- Jin-Kyoung Kim
- Department of Animal, Dairy, and Veterinary Sciences; Utah Science Technology and Research, College of Agriculture and Applied Sciences, Utah State University, Logan, Utah, United States of America
| | - Jeong-Min Kim
- Department of Microbiology, College of Medicine, Chungbuk National University, Cheongju, South Korea
| | - Byung-Hak Song
- Department of Animal, Dairy, and Veterinary Sciences; Utah Science Technology and Research, College of Agriculture and Applied Sciences, Utah State University, Logan, Utah, United States of America
| | - Sang-Im Yun
- Department of Animal, Dairy, and Veterinary Sciences; Utah Science Technology and Research, College of Agriculture and Applied Sciences, Utah State University, Logan, Utah, United States of America
| | - Gil-Nam Yun
- Department of Microbiology, College of Medicine, Chungbuk National University, Cheongju, South Korea
| | - Sung-June Byun
- Animal Biotechnology Division, Korea National Institute of Animal Science, Suwon, South Korea
| | - Young-Min Lee
- Department of Animal, Dairy, and Veterinary Sciences; Utah Science Technology and Research, College of Agriculture and Applied Sciences, Utah State University, Logan, Utah, United States of America
- * E-mail:
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28
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Roby JA, Setoh YX, Hall RA, Khromykh AA. Post-translational regulation and modifications of flavivirus structural proteins. J Gen Virol 2015; 96:1551-69. [PMID: 25711963 DOI: 10.1099/vir.0.000097] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Flaviviruses are a group of single-stranded, positive-sense RNA viruses that generally circulate between arthropod vectors and susceptible vertebrate hosts, producing significant human and veterinary disease burdens. Intensive research efforts have broadened our scientific understanding of the replication cycles of these viruses and have revealed several elegant and tightly co-ordinated post-translational modifications that regulate the activity of viral proteins. The three structural proteins in particular - capsid (C), pre-membrane (prM) and envelope (E) - are subjected to strict regulatory modifications as they progress from translation through virus particle assembly and egress. The timing of proteolytic cleavage events at the C-prM junction directly influences the degree of genomic RNA packaging into nascent virions. Proteolytic maturation of prM by host furin during Golgi transit facilitates rearrangement of the E proteins at the virion surface, exposing the fusion loop and thus increasing particle infectivity. Specific interactions between the prM and E proteins are also important for particle assembly, as prM acts as a chaperone, facilitating correct conformational folding of E. It is only once prM/E heterodimers form that these proteins can be secreted efficiently. The addition of branched glycans to the prM and E proteins during virion transit also plays a key role in modulating the rate of secretion, pH sensitivity and infectivity of flavivirus particles. The insights gained from research into post-translational regulation of structural proteins are beginning to be applied in the rational design of improved flavivirus vaccine candidates and make attractive targets for the development of novel therapeutics.
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Affiliation(s)
- Justin A Roby
- 1Australian Infectious Diseases Research Centre, The University of Queensland, Australia 2School of Chemistry and Molecular Biosciences, The University of Queensland, Australia
| | - Yin Xiang Setoh
- 1Australian Infectious Diseases Research Centre, The University of Queensland, Australia 2School of Chemistry and Molecular Biosciences, The University of Queensland, Australia
| | - Roy A Hall
- 1Australian Infectious Diseases Research Centre, The University of Queensland, Australia 2School of Chemistry and Molecular Biosciences, The University of Queensland, Australia
| | - Alexander A Khromykh
- 1Australian Infectious Diseases Research Centre, The University of Queensland, Australia 2School of Chemistry and Molecular Biosciences, The University of Queensland, Australia
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29
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Characterization of the mode of action of a potent dengue virus capsid inhibitor. J Virol 2014; 88:11540-55. [PMID: 25056895 DOI: 10.1128/jvi.01745-14] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
UNLABELLED Dengue viruses (DV) represent a significant global health burden, with up to 400 million infections every year and around 500,000 infected individuals developing life-threatening disease. In spite of attempts to develop vaccine candidates and antiviral drugs, there is a lack of approved therapeutics for the treatment of DV infection. We have previously reported the identification of ST-148, a small-molecule inhibitor exhibiting broad and potent antiviral activity against DV in vitro and in vivo (C. M. Byrd et al., Antimicrob. Agents Chemother. 57:15-25, 2013, doi:10 .1128/AAC.01429-12). In the present study, we investigated the mode of action of this promising compound by using a combination of biochemical, virological, and imaging-based techniques. We confirmed that ST-148 targets the capsid protein and obtained evidence of bimodal antiviral activity affecting both assembly/release and entry of infectious DV particles. Importantly, by using a robust bioluminescence resonance energy transfer-based assay, we observed an ST-148-dependent increase of capsid self-interaction. These results were corroborated by molecular modeling studies that also revealed a plausible model for compound binding to capsid protein and inhibition by a distinct resistance mutation. These results suggest that ST-148-enhanced capsid protein self-interaction perturbs assembly and disassembly of DV nucleocapsids, probably by inducing structural rigidity. Thus, as previously reported for other enveloped viruses, stabilization of capsid protein structure is an attractive therapeutic concept that also is applicable to flaviviruses. IMPORTANCE Dengue viruses are arthropod-borne viruses representing a significant global health burden. They infect up to 400 million people and are endemic to subtropical and tropical areas of the world. Currently, there are neither vaccines nor approved therapeutics for the prophylaxis or treatment of DV infections, respectively. This study reports the characterization of the mode of action of ST-148, a small-molecule capsid inhibitor with potent antiviral activity against all DV serotypes. Our results demonstrate that ST-148 stabilizes capsid protein self-interaction, thereby likely perturbing assembly and disassembly of viral nucleocapsids by inducing structural rigidity. This, in turn, might interfere with the release of viral RNA from incoming nucleocapsids (uncoating) as well as assembly of progeny virus particles. As previously reported for other enveloped viruses, we propose the capsid as a novel tractable target for flavivirus inhibitors.
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30
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Membranous replication factories induced by plus-strand RNA viruses. Viruses 2014; 6:2826-57. [PMID: 25054883 PMCID: PMC4113795 DOI: 10.3390/v6072826] [Citation(s) in RCA: 200] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2014] [Revised: 06/02/2014] [Accepted: 06/24/2014] [Indexed: 12/13/2022] Open
Abstract
In this review, we summarize the current knowledge about the membranous replication factories of members of plus-strand (+) RNA viruses. We discuss primarily the architecture of these complex membrane rearrangements, because this topic emerged in the last few years as electron tomography has become more widely available. A general denominator is that two “morphotypes” of membrane alterations can be found that are exemplified by flaviviruses and hepaciviruses: membrane invaginations towards the lumen of the endoplasmatic reticulum (ER) and double membrane vesicles, representing extrusions also originating from the ER, respectively. We hypothesize that either morphotype might reflect common pathways and principles that are used by these viruses to form their membranous replication compartments.
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31
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Highly efficient production of a dengue pseudoinfectious virus. Vaccine 2014; 32:3854-60. [PMID: 24797700 DOI: 10.1016/j.vaccine.2014.03.091] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Revised: 03/01/2014] [Accepted: 03/26/2014] [Indexed: 02/05/2023]
Abstract
Dengue is a major infectious disease that affects people living in tropical and subtropical regions around the world. The causative agents are dengue virus serotype 1, 2, 3, and 4 (DENV1, 2, 3, and 4). Developing a vaccine for dengue is a high priority for public health, but traditional methods have faced numerous obstacles due to the unique immunopathogenesis of dengue virus infection. Here, we report a novel dengue vaccine candidate based on dengue pseudoinfectious virus (PIV) produced by the incorporation of a dengue subgenomic replicon into viral particles in highly efficient packaging cells. The subgenomic replicon was constructed by deleting the capsid protein (C) gene from the dengue viral genome and optimizing the signal peptide sequence of pre-membrane protein (prM) to facilitate the formation of viral particles. Packaging cells were developed for inducible expression of a bi-protein Cpr, where the protein pr is the "pr" segment of viral protein prM that holds the protein C on the endoplasmic reticulum (ER). When the replicon was introduced into the packaging cells, protein C was released from the bi-protein Cpr by a replicon-encoded viral protease. Coordinate expression of viral structural proteins by the replicon and packaging cells led to the incorporation of the replicon into viral particle to produce PIVs. Animal tests showed that the dengue PIV vaccine was highly immunogenic and the immune response protected mice challenged with a hundred-fold LD50 inoculation of dengue virus. The method described here has the potential to be applied to vaccine development for other flaviviruses.
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32
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Kaufusi PH, Kelley JF, Yanagihara R, Nerurkar VR. Induction of endoplasmic reticulum-derived replication-competent membrane structures by West Nile virus non-structural protein 4B. PLoS One 2014; 9:e84040. [PMID: 24465392 PMCID: PMC3896337 DOI: 10.1371/journal.pone.0084040] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2013] [Accepted: 11/19/2013] [Indexed: 01/31/2023] Open
Abstract
Replication of flaviviruses (family Flaviviridae) occurs in specialized virus-induced membrane structures (IMS). The cellular composition of these IMS varies for different flaviviruses implying different organelle origins for IMS biogenesis. The role of flavivirus non-structural (NS) proteins for the alteration of IMS remains controversial. In this report, we demonstrate that West Nile virus strain New York 99 (WNVNY99) remodels the endoplasmic reticulum (ER) membrane to generate specialized IMS. Within these structures, we observed an element of the cis-Golgi, viral double-stranded RNA, and viral-envelope, NS1, NS4A and NS4B proteins using confocal immunofluorescence microscopy. Biochemical analysis and microscopy revealed that NS4B lacking the 2K-signal peptide associates with the ER membrane where it initiates IMS formation in WNV-infected cells. Co-transfection studies indicated that NS4A and NS4B always remain co-localized in the IMS and are associated with the same membrane fractions, suggesting that these proteins function cooperatively in virus replication and may be an ideal target for antiviral drug discovery.
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Affiliation(s)
- Pakieli H. Kaufusi
- Department of Tropical Medicine, Medical Microbiology and Pharmacology, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, Hawaii, United States of America
- Pacific Center for Emerging Infectious Diseases Research, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, Hawaii, United States of America
| | - James F. Kelley
- Department of Tropical Medicine, Medical Microbiology and Pharmacology, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, Hawaii, United States of America
- Pacific Center for Emerging Infectious Diseases Research, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, Hawaii, United States of America
| | - Richard Yanagihara
- Department of Tropical Medicine, Medical Microbiology and Pharmacology, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, Hawaii, United States of America
- Department of Pediatrics, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, Hawaii, United States of America
- Pacific Center for Emerging Infectious Diseases Research, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, Hawaii, United States of America
| | - Vivek R. Nerurkar
- Department of Tropical Medicine, Medical Microbiology and Pharmacology, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, Hawaii, United States of America
- Pacific Center for Emerging Infectious Diseases Research, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, Hawaii, United States of America
- * E-mail:
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Hoenen A, Gillespie L, Morgan G, van der Heide P, Khromykh A, Mackenzie J. The West Nile virus assembly process evades the conserved antiviral mechanism of the interferon-induced MxA protein. Virology 2014; 448:104-16. [DOI: 10.1016/j.virol.2013.10.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2013] [Revised: 06/28/2013] [Accepted: 10/03/2013] [Indexed: 02/04/2023]
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Replication cycle and molecular biology of the West Nile virus. Viruses 2013; 6:13-53. [PMID: 24378320 PMCID: PMC3917430 DOI: 10.3390/v6010013] [Citation(s) in RCA: 95] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2013] [Revised: 12/12/2013] [Accepted: 12/12/2013] [Indexed: 12/27/2022] Open
Abstract
West Nile virus (WNV) is a member of the genus Flavivirus in the family Flaviviridae. Flaviviruses replicate in the cytoplasm of infected cells and modify the host cell environment. Although much has been learned about virion structure and virion-endosomal membrane fusion, the cell receptor(s) used have not been definitively identified and little is known about the early stages of the virus replication cycle. Members of the genus Flavivirus differ from members of the two other genera of the family by the lack of a genomic internal ribosomal entry sequence and the creation of invaginations in the ER membrane rather than double-membrane vesicles that are used as the sites of exponential genome synthesis. The WNV genome 3' and 5' sequences that form the long distance RNA-RNA interaction required for minus strand initiation have been identified and contact sites on the 5' RNA stem loop for NS5 have been mapped. Structures obtained for many of the viral proteins have provided information relevant to their functions. Viral nonstructural protein interactions are complex and some may occur only in infected cells. Although interactions between many cellular proteins and virus components have been identified, the functions of most of these interactions have not been delineated.
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Salvetti A, Greco A. Viruses and the nucleolus: the fatal attraction. Biochim Biophys Acta Mol Basis Dis 2013; 1842:840-7. [PMID: 24378568 PMCID: PMC7135015 DOI: 10.1016/j.bbadis.2013.12.010] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2013] [Revised: 12/05/2013] [Accepted: 12/09/2013] [Indexed: 12/13/2022]
Abstract
Viruses are small obligatory parasites and as a consequence, they have developed sophisticated strategies to exploit the host cell's functions to create an environment that favors their own replication. A common feature of most – if not all – families of human and non-human viruses concerns their interaction with the nucleolus. The nucleolus is a multifunctional nuclear domain, which, in addition to its well-known role in ribosome biogenesis, plays several crucial other functions. Viral infection induces important nucleolar alterations. Indeed, during viral infection numerous viral components localize in nucleoli, while various host nucleolar proteins are redistributed in other cell compartments or are modified, and non-nucleolar cellular proteins reach the nucleolus. This review highlights the interactions reported between the nucleolus and some human or animal viral families able to establish a latent or productive infection, selected on the basis of their known interactions with the nucleolus and the nucleolar activities, and their links with virus replication and/or pathogenesis. This article is part of a Special Issue entitled: Role of the Nucleolus in Human Disease. Most viruses interact with the nucleolus that plays a major role in virus life cycle. Virus/nucleolus interaction is crucial for virus replication and pathogenesis. Role of nucleoli in the infection with selected RNA viruses and herpes viruses
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Affiliation(s)
- Anna Salvetti
- Centre International de Recherche en Infectiologie (CIRI, International Center for Infectiology Research), Inserm U1111, CNRS UMR5308, Ecole Normale Supérieure de Lyon, Université de Lyon, 46 Allée d'Italie, 69365 Lyon CEDEX, France; LabEx Ecofect, Université de Lyon, 69007 Lyon, France.
| | - Anna Greco
- Centre International de Recherche en Infectiologie (CIRI, International Center for Infectiology Research), Inserm U1111, CNRS UMR5308, Ecole Normale Supérieure de Lyon, Université de Lyon, 46 Allée d'Italie, 69365 Lyon CEDEX, France; LabEx Ecofect, Université de Lyon, 69007 Lyon, France.
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Chong MK, Chua AJS, Tan TTT, Tan SH, Ng ML. Microscopy techniques in flavivirus research. Micron 2013; 59:33-43. [PMID: 24530363 DOI: 10.1016/j.micron.2013.12.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2013] [Revised: 12/11/2013] [Accepted: 12/11/2013] [Indexed: 11/29/2022]
Abstract
The Flavivirus genus is composed of many medically important viruses that cause high morbidity and mortality, which include Dengue and West Nile viruses. Various molecular and biochemical techniques have been developed in the endeavour to study flaviviruses. However, microscopy techniques still have irreplaceable roles in the identification of novel virus pathogens and characterization of morphological changes in virus-infected cells. Fluorescence microscopy contributes greatly in understanding the fundamental viral protein localizations and virus-host protein interactions during infection. Electron microscopy remains the gold standard for visualizing ultra-structural features of virus particles and infected cells. New imaging techniques and combinatory applications are continuously being developed to push the limit of resolution and extract more quantitative data. Currently, correlative live cell imaging and high resolution three-dimensional imaging have already been achieved through the tandem use of optical and electron microscopy in analyzing biological specimens. Microscopy techniques are also used to measure protein binding affinities and determine the mobility pattern of proteins in cells. This chapter will consolidate on the applications of various well-established microscopy techniques in flavivirus research, and discuss how recently developed microscopy techniques can potentially help advance our understanding in these membrane viruses.
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Affiliation(s)
- Mun Keat Chong
- Flavivirology Laboratory, Department of Microbiology, Yong Loo Lin School of Medicine, National University Health System, National University of Singapore, 5 Science Drive 2, MD4 Level 3, Singapore 117545, Singapore
| | - Anthony Jin Shun Chua
- Flavivirology Laboratory, Department of Microbiology, Yong Loo Lin School of Medicine, National University Health System, National University of Singapore, 5 Science Drive 2, MD4 Level 3, Singapore 117545, Singapore; NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, Centre for Life Sciences (CeLS), 28 Medical Drive, #05-01, Singapore 117456, Singapore
| | - Terence Tze Tong Tan
- Flavivirology Laboratory, Department of Microbiology, Yong Loo Lin School of Medicine, National University Health System, National University of Singapore, 5 Science Drive 2, MD4 Level 3, Singapore 117545, Singapore
| | - Suat Hoon Tan
- Electron Microscopy Unit, Yong Loo Lin School of Medicine, National University Health System, National University of Singapore, 12 Medical Drive, MD5, Singapore 117597, Singapore
| | - Mah Lee Ng
- Flavivirology Laboratory, Department of Microbiology, Yong Loo Lin School of Medicine, National University Health System, National University of Singapore, 5 Science Drive 2, MD4 Level 3, Singapore 117545, Singapore; NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, Centre for Life Sciences (CeLS), 28 Medical Drive, #05-01, Singapore 117456, Singapore; Electron Microscopy Unit, Yong Loo Lin School of Medicine, National University Health System, National University of Singapore, 12 Medical Drive, MD5, Singapore 117597, Singapore.
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Morphogenesis of pestiviruses: new insights from ultrastructural studies of strain Giraffe-1. J Virol 2013; 88:2717-24. [PMID: 24352462 DOI: 10.1128/jvi.03237-13] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Knowledge on the morphogenesis of pestiviruses is limited due to low virus production in infected cells. In order to localize virion morphogenesis and replication sites of pestiviruses and to examine intracellular virion transport, a cell culture model was established to facilitate ultrastructural studies. Based on results of virus growth kinetic analysis and quantification of viral RNA, pestivirus strain Giraffe-1 turned out to be a suitable candidate for studies on virion generation and export from culture cells. Using conventional transmission electron microscopy and single-tilt electron tomography, we found virions located predominately in the lumen of the endoplasmic reticulum (ER) in infected cells and were able to depict the budding process of virions at ER membranes. Colocalization of the viral core protein and the envelope glycoprotein E2 with the ER marker protein disulfide isomerase (PDI) was demonstrated by immunogold labeling of cryosections. Moreover, pestivirions could be shown in transport vesicles and the Golgi complex and during exocytosis. Interestingly, viral capsid protein and double-stranded RNA (dsRNA) were detected in multivesicular bodies (MVBs), which implies that the endosomal compartment plays a role in pestiviral replication. Significant cellular membrane alterations such as those described for members of the Flavivirus and Hepacivirus genera were not found. Based on the gained morphological data, we present a consistent model of pestivirus morphogenesis.
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Tsuda Y, Mori Y, Abe T, Yamashita T, Okamoto T, Ichimura T, Moriishi K, Matsuura Y. Nucleolar Protein B23 Interacts with Japanese Encephalitis Virus Core Protein and Participates in Viral Replication. Microbiol Immunol 2013; 50:225-34. [PMID: 16547420 DOI: 10.1111/j.1348-0421.2006.tb03789.x] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Japanese encephalitis virus (JEV) core protein is detected not only in the cytoplasm but also in the nucleoli of infected cells. We previously showed that a mutant JEV lacking the nucleolar localization of the core protein impaired viral replication in mammalian cells. In this study, we identified a nucleolar phosphoprotein B23 as a protein binding with the core protein of JEV but not with that of dengue virus. The region binding with JEV core protein was mapped to amino acid residues 38 to 77 of B23. Upon JEV infection, some fraction of B23 was translocated from the nucleoli to the cytoplasm, and cytoplasmic B23 was colocalized with the core protein of wild-type JEV but not with that of the mutant JEV. Furthermore, overexpression of dominant negatives of B23 reduced JEV replication. These results suggest that B23 plays an important role in the intracellular localization of the core protein and replication of JEV.
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Affiliation(s)
- Yoshimi Tsuda
- Department of Molecular Virology, Research Institute for Microbial Diseases, Osaka University, Suita, Osaka 565-0871, Japan
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Agrawal T, Sharvani V, Nair D, Medigeshi GR. Japanese encephalitis virus disrupts cell-cell junctions and affects the epithelial permeability barrier functions. PLoS One 2013; 8:e69465. [PMID: 23894488 PMCID: PMC3722119 DOI: 10.1371/journal.pone.0069465] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2013] [Accepted: 06/11/2013] [Indexed: 02/07/2023] Open
Abstract
Japanese encephalitis virus (JEV) is a neurotropic flavivirus, which causes viral encephalitis leading to death in about 20-30% of severely-infected people. Although JEV is known to be a neurotropic virus its replication in non-neuronal cells in peripheral tissues is likely to play a key role in viral dissemination and pathogenesis. We have investigated the effect of JEV infection on cellular junctions in a number of non-neuronal cells. We show that JEV affects the permeability barrier functions in polarized epithelial cells at later stages of infection. The levels of some of the tight and adherens junction proteins were reduced in epithelial and endothelial cells and also in hepatocytes. Despite the induction of antiviral response, barrier disruption was not mediated by secreted factors from the infected cells. Localization of tight junction protein claudin-1 was severely perturbed in JEV-infected cells and claudin-1 partially colocalized with JEV in intracellular compartments and targeted for lysosomal degradation. Expression of JEV-capsid alone significantly affected the permeability barrier functions in these cells. Our results suggest that JEV infection modulates cellular junctions in non-neuronal cells and compromises the permeability barrier of epithelial and endothelial cells which may play a role in viral dissemination in peripheral tissues.
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Affiliation(s)
- Tanvi Agrawal
- Vaccine and Infectious Disease Research Center, Translational Health Science and Technology Institute, Gurgaon, India
| | - Vats Sharvani
- Vaccine and Infectious Disease Research Center, Translational Health Science and Technology Institute, Gurgaon, India
| | - Deepa Nair
- Vaccine and Infectious Disease Research Center, Translational Health Science and Technology Institute, Gurgaon, India
| | - Guruprasad R. Medigeshi
- Vaccine and Infectious Disease Research Center, Translational Health Science and Technology Institute, Gurgaon, India
- * E-mail:
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Bhuvanakantham R, Ng ML. West Nile virus and dengue virus capsid protein negates the antiviral activity of human Sec3 protein through the proteasome pathway. Cell Microbiol 2013; 15:1688-706. [PMID: 23522008 DOI: 10.1111/cmi.12143] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2011] [Revised: 03/13/2013] [Accepted: 03/15/2013] [Indexed: 12/22/2022]
Abstract
Flavivirus capsid (C) protein is a key structural component of virus particles. The non-structural role of C protein in the pathogenesis of arthropod-borne flaviviruses is not clearly deciphered. This study showed that West Nile virus (WNV) and dengue virus (DENV) utilized C protein to reduce human Sec3p (hSec3p) levels at post-transcriptional level through activation of chymotrypsin-like proteolytic function of 20S proteasome. Mutagenesis studies confirmed amino acids 14, 109-114 of WNV C protein and 13, 102-107 of DENV C protein played an important role in activating the proteolytic function of 20S proteasome. Amino acid residues at 14 (WNV) and 13 (DENV) of C protein were important for C protein-hSec3p binding and physical interaction between C protein and hSec3p was essential to execute hSec3p degradation. Degradation motif required to degrade hSec3p resided between amino acid residues 109-114 of WNV C protein and 102-107 of DENV C protein. Proteasomes, hSec3p binding motif and degradation motif on C protein must be intact for efficient flavivirus production. Clinical isolates of DENV showed more pronounced effect in manipulating the proteasomes and reducing hSec3p levels. This study portrayed the non-structural function of C protein that helped the flavivirus to nullify the antiviral activity of hSec3p by accelerating its degradation and facilitating efficient binding of elongation factor 1α with flaviviral RNA genome.
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Affiliation(s)
- Raghavan Bhuvanakantham
- Flavivirology Laboratory, Department of Microbiology, Yong Loo Lin School of Medicine, National University of Singapore, 5 Science Drive 2, Singapore, 117597
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Scagnolari C, Caputo B, Trombetti S, Cacciotti G, Soldà A, Spano L, Villari P, Della Torre A, Nowotny N, Antonelli G. Usutu virus growth in human cell lines: induction of and sensitivity to type I and III interferons. J Gen Virol 2012; 94:789-795. [PMID: 23255619 DOI: 10.1099/vir.0.046433-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The mechanisms of Usutu virus (USUV) pathogenesis are largely unknown. The aim of this study was to evaluate the sensitivity of USUV to interferon (IFN) and the capacity of USUV to stimulate IFN production. Initial experiments were conducted to characterize the susceptibility of human cell lines to USUV infection and to evaluate the single-growth cycle replication curve of USUV. Results indicate that USUV is able to infect a variety of human cell lines, completing the replication cycle in Hep-2 and Vero cells within 48 h. Pre-treatment of cells with types I and III IFNs significantly inhibited the replication of USUV. However, the inhibitory effects of IFNs were considerably less if IFN was added after viral infection had been initiated. Also, USUV weakly induced types I and III IFNs.
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Affiliation(s)
- Carolina Scagnolari
- Department of Molecular Medicine, Laboratory of Virology, 'Sapienza' University of Rome, Viale di Porta Tiburtina 28, 00185, Rome, Italy
| | - Beniamino Caputo
- Parasitology Unit, Department of Public Health and Infectious Diseases, 'Sapienza' University of Rome, Piazzale Aldo Moro 5, 00185 Rome, Italy
| | - Simona Trombetti
- Department of Molecular Medicine, Laboratory of Virology, 'Sapienza' University of Rome, Viale di Porta Tiburtina 28, 00185, Rome, Italy
| | - Giulia Cacciotti
- Department of Molecular Medicine, Laboratory of Virology, 'Sapienza' University of Rome, Viale di Porta Tiburtina 28, 00185, Rome, Italy
| | - Annalisa Soldà
- Department of Molecular Medicine, Laboratory of Virology, 'Sapienza' University of Rome, Viale di Porta Tiburtina 28, 00185, Rome, Italy
| | - Lucia Spano
- Department of Molecular Medicine, Laboratory of Virology, 'Sapienza' University of Rome, Viale di Porta Tiburtina 28, 00185, Rome, Italy
| | - Paolo Villari
- Department of Public Health and Infectious Diseases, 'Sapienza' University of Rome, Viale Regina Elena 324, 00185 Rome, Italy
| | - Alessandra Della Torre
- Parasitology Unit, Department of Public Health and Infectious Diseases, 'Sapienza' University of Rome, Piazzale Aldo Moro 5, 00185 Rome, Italy
| | - Norbert Nowotny
- Department of Microbiology and Immunology, College of Medicine and Health Sciences, Sultan Qaboos University, PO Box 35, Al-Khod, Muscat 123, Oman.,Viral Zoonoses, Emerging and Vector-Borne Infections Group, Institute of Virology, University of Veterinary Medicine Vienna, Veterinärplatz 1, A-1210 Vienna, Austria
| | - Guido Antonelli
- Department of Molecular Medicine, Laboratory of Virology, 'Sapienza' University of Rome, Viale di Porta Tiburtina 28, 00185, Rome, Italy
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Noda M, Masrinoul P, Punkum C, Pipattanaboon C, Ramasoota P, Setthapramote C, Sasaki T, Sasayama M, Yamashita A, Kurosu T, Ikuta K, Okabayashi T. Limited cross-reactivity of mouse monoclonal antibodies against Dengue virus capsid protein among four serotypes. Biologics 2012; 6:409-16. [PMID: 23209363 PMCID: PMC3512249 DOI: 10.2147/btt.s37792] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Background Dengue illness is one of the important mosquito-borne viral diseases in tropical and subtropical regions. Four serotypes of dengue virus (DENV-1, DENV-2, DENV-3, and DENV-4) are classified in the Flavivirus genus of the family Flaviviridae. We prepared monoclonal antibodies against DENV capsid protein from mice immunized with DENV-2 and determined the cross-reactivity with each serotype of DENV and Japanese encephalitis virus. Methods and results To clarify the relationship between the cross-reactivity of monoclonal antibodies and the diversity of these viruses, we examined the situations of flaviviruses by analyses of phylogenetic trees. Among a total of 60 prepared monoclonal antibodies specific for DENV, five monoclonal antibodies stained the nuclei of infected cells and were found to be specific to the capsid protein. Three were specific to DENV-2, while the other two were cross-reactive with DENV-2 and DENV-4. No monoclonal antibodies were cross-reactive with all four serotypes. Phylogenetic analysis of DENV amino acid sequences of the capsid protein revealed that DENV-2 and DENV-4 were clustered in the same branch, while DENV-1 and DENV-3 were clustered in the other branch. However, these classifications of the capsid protein were different from those of the envelope and nonstructural 1 proteins. Phylogenetic distances between the four serotypes of DENV were as different as those of other flaviviruses, such as Japanese encephalitis virus and West Nile virus. Large variations in the DENV serotypes were comparable with the differences between species of flavivirus. Furthermore, the diversity of flavivirus capsid protein was much greater than that of envelope and nonstructural 1 proteins. Conclusion In this study, we produced specific monoclonal antibodies that can be used to detect DENV-2 capsid protein, but not a cross-reactive one with all serotypes of DENV capsid protein. The high diversity of the DENV capsid protein sequence by phylogenetic analysis supported the low cross-reactivity of monoclonal antibodies against DENV capsid protein.
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Affiliation(s)
- Megumi Noda
- Mahidol-Osaka Center for Infectious Diseases, Faculty of Tropical Medicine, Mahidol University, Ratchathewi, Bangkok, Thailand
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Parreira R, Cook S, Lopes Â, de Matos AP, de Almeida APG, Piedade J, Esteves A. Genetic characterization of an insect-specific flavivirus isolated from Culex theileri mosquitoes collected in southern Portugal. Virus Res 2012; 167:152-61. [PMID: 22579596 PMCID: PMC3919203 DOI: 10.1016/j.virusres.2012.04.010] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2011] [Revised: 03/30/2012] [Accepted: 04/11/2012] [Indexed: 12/04/2022]
Abstract
We describe the full genetic characterization of an insect-specific flavivirus (ISF) from Culex theileri (Theobald) mosquitoes collected in Portugal. This represents the first isolation and full characterization of an ISF from Portuguese mosquitoes. The virus, designated CTFV, for Culex theileri flavivirus, was isolated in the C6/36 Stegomyia albopicta (=Aedes albopictus) cell line, and failed to replicate in vertebrate (Vero) cells in common with other ISFs. The CTFV genome encodes a single polyprotein with 3357 residues showing all the features expected for those of flaviviruses. Phylogenetic analyses based on all ISF sequences available to date, place CTFV among Culex-associated flaviviruses, grouping with recently published NS5 partial sequences documented from mosquitoes collected in the Iberian Peninsula, and with Quang Binh virus (isolated in Vietnam) as a close relative. No CTFV sequences were found integrated in their host's genome using a range of specific PCR primers designed to the prM/E, NS3, and NS5 region.
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Affiliation(s)
- Ricardo Parreira
- Unidade de Microbiologia Médica, Grupo de Virologia, Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa, Rua da Junqueira 100, 1349-008 Lisboa, Portugal.
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Martín-Acebes MA, Saiz JC. West Nile virus: A re-emerging pathogen revisited. World J Virol 2012; 1:51-70. [PMID: 24175211 PMCID: PMC3782267 DOI: 10.5501/wjv.v1.i2.51] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/19/2011] [Revised: 02/16/2012] [Accepted: 03/05/2012] [Indexed: 02/05/2023] Open
Abstract
West Nile virus (WNV), a flavivirus of the Flaviviridae family, is maintained in nature in an enzootic transmission cycle between avian hosts and ornithophilic mosquito vectors, although the virus occasionally infects other vertebrates. WNV causes sporadic disease outbreaks in horses and humans, which may result in febrile illness, meningitis, encephalitis and flaccid paralysis. Until recently, its medical and veterinary health concern was relatively low; however, the number, frequency and severity of outbreaks with neurological consequences in humans and horses have lately increased in Europe and the Mediterranean basin. Since its introduction in the Americas, the virus spread across the continent with worrisome consequences in bird mortality and a considerable number of outbreaks among humans and horses, which have resulted in the largest epidemics of neuroinvasive WNV disease ever documented. Surprisingly, its incidence in human and animal health is very different in Central and South America, and the reasons for it are not yet understood. Even though great advances have been obtained lately regarding WNV infection, and although efficient equine vaccines are available, no specific treatments or vaccines for human use are on the market. This review updates the most recent investigations in different aspects of WNV life cycle: molecular virology, transmission dynamics, host range, clinical presentations, epidemiology, ecology, diagnosis, control, and prevention, and highlights some aspects that certainly require further research.
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Affiliation(s)
- Miguel A Martín-Acebes
- Miguel A Martín-Acebes, Juan-Carlos Saiz, Department of Biotechnology, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria, 28040 Madrid, Spain
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Mutational analysis of the West Nile virus NS4B protein. Virology 2012; 426:22-33. [PMID: 22314017 DOI: 10.1016/j.virol.2011.11.022] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2011] [Revised: 04/30/2011] [Accepted: 11/23/2011] [Indexed: 01/29/2023]
Abstract
West Nile virus NS4B is a small hydrophobic nonstructural protein approximately 27 kDa in size whose function is poorly understood. Amino acid substitutions were introduced into the NS4B protein primarily targeting two distinct regions; the N-terminal domain (residues 35 through 60) and the central hydrophobic domain (residues 95 through 120). Only the NS4B P38G substitution was associated with both temperature-sensitive and small-plaque phenotypes. Importantly, this mutation was found to attenuate neuroinvasiveness greater than 10,000,000-fold and lower viremia titers compared to the wild-type NY99 virus in a mouse model. Full genome sequencing of the NS4B P38G mutant virus revealed two unexpected mutations at NS4B T116I and NS3 N480H (P38G/T116I/N480H), however, neither mutation alone was temperature sensitive or attenuated in mice. Following incubation of P38G/T116I/N480H at 41°C, five mutants encoding compensatory substitutions in the NS4B protein exhibited a reduction in the temperature-sensitive phenotype and reversion to a virulent phenotype in the mouse model.
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Li J, Huang R, Liao W, Chen Z, Zhang S, Huang R. Dengue virus utilizes calcium modulating cyclophilin-binding ligand to subvert apoptosis. Biochem Biophys Res Commun 2012; 418:622-7. [DOI: 10.1016/j.bbrc.2012.01.050] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2011] [Accepted: 01/10/2012] [Indexed: 12/16/2022]
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Cerutti A, Maillard P, Minisini R, Vidalain PO, Roohvand F, Pecheur EI, Pirisi M, Budkowska A. Identification of a functional, CRM-1-dependent nuclear export signal in hepatitis C virus core protein. PLoS One 2011; 6:e25854. [PMID: 22039426 PMCID: PMC3200325 DOI: 10.1371/journal.pone.0025854] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2011] [Accepted: 09/12/2011] [Indexed: 02/06/2023] Open
Abstract
Hepatitis C virus (HCV) infection is a major cause of chronic liver disease worldwide. HCV core protein is involved in nucleocapsid formation, but it also interacts with multiple cytoplasmic and nuclear molecules and plays a crucial role in the development of liver disease and hepatocarcinogenesis. The core protein is found mostly in the cytoplasm during HCV infection, but also in the nucleus in patients with hepatocarcinoma and in core-transgenic mice. HCV core contains nuclear localization signals (NLS), but no nuclear export signal (NES) has yet been identified.We show here that the aa(109-133) region directs the translocation of core from the nucleus to the cytoplasm by the CRM-1-mediated nuclear export pathway. Mutagenesis of the three hydrophobic residues (L119, I123 and L126) in the identified NES or in the sequence encoding the mature core aa(1-173) significantly enhanced the nuclear localisation of the corresponding proteins in transfected Huh7 cells. Both the NES and the adjacent hydrophobic sequence in domain II of core were required to maintain the core protein or its fragments in the cytoplasmic compartment. Electron microscopy studies of the JFH1 replication model demonstrated that core was translocated into the nucleus a few minutes after the virus entered the cell. The blockade of nucleocytoplasmic export by leptomycin B treatment early in infection led to the detection of core protein in the nucleus by confocal microscopy and coincided with a decrease in virus replication.Our data suggest that the functional NLS and NES direct HCV core protein shuttling between the cytoplasmic and nuclear compartments, with at least some core protein transported to the nucleus. These new properties of HCV core may be essential for virus multiplication and interaction with nuclear molecules, influence cell signaling and the pathogenesis of HCV infection.
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Affiliation(s)
- Andrea Cerutti
- Unité Hépacivirus et Immunité Innée, Département de Virologie, Institut Pasteur, Paris, France
- CNRS, URA3015, Paris, France
- Dipartimento di Medicina Clinica e Sperimentale, Università del Piemonte Orientale “Amedeo Avogadro”, Novara, Italy
| | - Patrick Maillard
- Unité Hépacivirus et Immunité Innée, Département de Virologie, Institut Pasteur, Paris, France
- CNRS, URA3015, Paris, France
| | - Rosalba Minisini
- Dipartimento di Medicina Clinica e Sperimentale, Università del Piemonte Orientale “Amedeo Avogadro”, Novara, Italy
| | - Pierre-Olivier Vidalain
- CNRS, URA3015, Paris, France
- Unité de Génomique Virale et Vaccination, Département de Virologie, Institut Pasteur, Paris, France
| | - Farzin Roohvand
- Unité Hépacivirus et Immunité Innée, Département de Virologie, Institut Pasteur, Paris, France
- CNRS, URA3015, Paris, France
- Hepatitis and AIDS Department, Pasteur Institute of Iran, Teheran, Iran
| | - Eve-Isabelle Pecheur
- Université Lyon 1, Lyon, France
- CNRS, UMR5086, Lyon, France
- IBCP, Bases Moléculaires et Structurales des Systèmes Infectieux, Lyon, France
| | - Mario Pirisi
- Dipartimento di Medicina Clinica e Sperimentale, Università del Piemonte Orientale “Amedeo Avogadro”, Novara, Italy
| | - Agata Budkowska
- Unité Hépacivirus et Immunité Innée, Département de Virologie, Institut Pasteur, Paris, France
- CNRS, URA3015, Paris, France
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Heterogeneous nuclear ribonucleoprotein A2 participates in the replication of Japanese encephalitis virus through an interaction with viral proteins and RNA. J Virol 2011; 85:10976-88. [PMID: 21865391 DOI: 10.1128/jvi.00846-11] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Japanese encephalitis virus (JEV) is a mosquito-borne flavivirus that is kept in a zoonotic transmission cycle between pigs and mosquitoes. JEV causes infection of the central nervous system with a high mortality rate in dead-end hosts, including humans. Many studies have suggested that the flavivirus core protein is not only a component of nucleocapsids but also an important pathogenic determinant. In this study, we identified heterogeneous nuclear ribonucleoprotein A2 (hnRNP A2) as a binding partner of the JEV core protein by pulldown purification and mass spectrometry. Reciprocal coimmunoprecipitation analyses in transfected and infected cells confirmed a specific interaction between the JEV core protein and hnRNP A2. Expression of the JEV core protein induced cytoplasmic retention of hnRNP A2 in JEV subgenomic replicon cells. Small interfering RNA (siRNA)-mediated knockdown of hnRNP A2 resulted in a 90% reduction of viral RNA replication in cells infected with JEV, and the reduction was cancelled by the expression of an siRNA-resistant hnRNP A2 mutant. In addition to the core protein, hnRNP A2 also associated with JEV nonstructural protein 5, which has both methyltransferase and RNA-dependent RNA polymerase activities, and with the 5'-untranslated region of the negative-sense JEV RNA. During one-step growth, synthesis of both positive- and negative-strand JEV RNAs was delayed by the knockdown of hnRNP A2. These results suggest that hnRNP A2 plays an important role in the replication of JEV RNA through the interaction with viral proteins and RNA.
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Affiliation(s)
- Mark O. J. Olson
- Dept. Biochemistry, University of Mississippi Medical Center, North State St. 2500, Jackson, 39216 Mississippi USA
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Kelley JF, Kaufusi PH, Volper EM, Nerurkar VR. Maturation of dengue virus nonstructural protein 4B in monocytes enhances production of dengue hemorrhagic fever-associated chemokines and cytokines. Virology 2011; 418:27-39. [PMID: 21810535 DOI: 10.1016/j.virol.2011.07.006] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2011] [Revised: 04/25/2011] [Accepted: 07/03/2011] [Indexed: 11/19/2022]
Abstract
High levels of viremia and chemokines and cytokines underlie the progression of severe dengue disease. Dengue virus (DENV) preferentially infects peripheral blood monocytes, which secrete elevated levels of immunomediators in patients with severe disease. Further, DENV nonstructural proteins (NS) are capable of modifying intracellular signaling, including interferon inhibition. We demonstrate that peak secretions of immunomediators such as IL-6, IL-8, IP-10, TNFα or IFNγ in DENV-infected monocytes correlate with maximum virus production and NS4B and NS5 are primarily responsible for the induction of immunomediators. Furthermore, we demonstrate that sequential NS4AB processing initiated by the viral protease NS2B3(pro) and via the intermediate 2KNS4B significantly enhances immunomediator induction. While the 2K-signal peptide is not essential for immunomediator induction, it plays a synergistic role with NS4B. These data suggest that NS4B maturation is important during innate immune signaling in DENV-infected monocytes. Given similar NS4B topologies and polyprotein processing across flaviviruses, NS4B may be an attractive target for developing Flavivirus-wide therapeutic interventions.
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Affiliation(s)
- James F Kelley
- Department of Tropical Medicine, Medical Microbiology and Pharmacology, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, HI 96813, USA
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