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Cherkashchenko L, Gros N, Trausch A, Neyret A, Hénaut M, Dubois G, Villeneuve M, Chable-Bessia C, Lyonnais S, Merits A, Muriaux D. Validation of flavivirus infectious clones carrying fluorescent markers for antiviral drug screening and replication studies. Front Microbiol 2023; 14:1201640. [PMID: 37779700 PMCID: PMC10541152 DOI: 10.3389/fmicb.2023.1201640] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Accepted: 08/17/2023] [Indexed: 10/03/2023] Open
Abstract
Flaviviruses have emerged as major arthropod-transmitted pathogens and represent an increasing public health problem worldwide. High-throughput screening can be facilitated using viruses that easily express detectable marker proteins. Therefore, developing molecular tools, such as reporter-carrying versions of flaviviruses, for studying viral replication and screening antiviral compounds represents a top priority. However, the engineering of flaviviruses carrying either fluorescent or luminescent reporters remains challenging due to the genetic instability caused by marker insertion; therefore, new approaches to overcome these limitations are needed. Here, we describe reverse genetic methods that include the design and validation of infectious clones of Zika, Kunjin, and Dengue viruses harboring different reporter genes for infection, rescue, imaging, and morphology using super-resolution microscopy. It was observed that different flavivirus constructs with identical designs displayed strikingly different genetic stabilities, and corresponding virions resembled wild-type virus particles in shape and size. A successful strategy was assessed to increase the stability of rescued reporter virus and permit antiviral drug screening based on quantitative automated fluorescence microscopy and replication studies.
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Affiliation(s)
- Liubov Cherkashchenko
- CEMIPAI UAR3725 CNRS, University of Montpellier, Montpellier, France
- Institute of Technology, University of Tartu, Tartu, Estonia
| | - Nathalie Gros
- CEMIPAI UAR3725 CNRS, University of Montpellier, Montpellier, France
| | - Alice Trausch
- CEMIPAI UAR3725 CNRS, University of Montpellier, Montpellier, France
| | - Aymeric Neyret
- CEMIPAI UAR3725 CNRS, University of Montpellier, Montpellier, France
| | - Mathilde Hénaut
- CEMIPAI UAR3725 CNRS, University of Montpellier, Montpellier, France
| | - Gregor Dubois
- CEMIPAI UAR3725 CNRS, University of Montpellier, Montpellier, France
| | | | | | | | - Andres Merits
- Institute of Technology, University of Tartu, Tartu, Estonia
| | - Delphine Muriaux
- CEMIPAI UAR3725 CNRS, University of Montpellier, Montpellier, France
- IRIM UMR9004 CNRS, University of Montpellier, Montpellier, France
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2
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Reis LAM, Silva EVPD, Dias DD, Freitas MNO, Caldeira RD, Araújo PADS, Silva FSD, Rosa Junior JW, Brandão RCF, Nascimento BLSD, Martins LC, Neto JPN. Vector Competence of Culex quinquefasciatus from Brazil for West Nile Virus. Trop Med Infect Dis 2023; 8:tropicalmed8040217. [PMID: 37104343 PMCID: PMC10144584 DOI: 10.3390/tropicalmed8040217] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Revised: 03/08/2023] [Accepted: 03/15/2023] [Indexed: 04/08/2023] Open
Abstract
West Nile virus is characterized as a neurotropic pathogen, which can cause West Nile fever and is transmitted by mosquitoes of the genus Culex. In 2018, the Instituto Evandro Chagas performed the first isolation of a WNV strain in Brazil from a horse brain sample. The present study aimed to evaluate the susceptibility of orally infected Cx. quinquefasciatus from the Amazon region of Brazil to become infected and transmit the WNV strain isolated in 2018. Oral infection was performed with blood meal artificially infected with WNV, followed by analysis of infection, dissemination, and transmission rates, as well as viral titers of body, head, and saliva samples. At the 21st dpi, the infection rate was 100%, the dissemination rate was 80%, and the transmission rate was 77%. These results indicate that Cx. quinquefasciatus is susceptible to oral infection by the Brazilian strain of WNV and may act as a possible vector of the virus since it was detected in saliva from the 21st dpi.
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Affiliation(s)
- Lúcia Aline Moura Reis
- Graduate Program in Parasitary Biology in the Amazon Region, Center of Biological and Health Sciences, State University of Pará, Belém 66095-663, Brazil
| | - Eliana Vieira Pinto da Silva
- Department of Arbovirology and Hemorrhagic Fevers, Evandro Chagas Institute—IEC/MS/SVSA, Ananindeua 67030-000, Brazil
| | - Daniel Damous Dias
- Graduate Program in Parasitary Biology in the Amazon Region, Center of Biological and Health Sciences, State University of Pará, Belém 66095-663, Brazil
| | - Maria Nazaré Oliveira Freitas
- Department of Arbovirology and Hemorrhagic Fevers, Evandro Chagas Institute—IEC/MS/SVSA, Ananindeua 67030-000, Brazil
| | - Rossela Damasceno Caldeira
- Graduate Program in Biology of Infectious and Parasitary Agents, Biological Sciences Institute, Federal University of Pará, Belém 66077-830, Brazil
| | - Pedro Arthur da Silva Araújo
- Graduate Program in Biology of Infectious and Parasitary Agents, Biological Sciences Institute, Federal University of Pará, Belém 66077-830, Brazil
| | - Fábio Silva da Silva
- Graduate Program in Parasitary Biology in the Amazon Region, Center of Biological and Health Sciences, State University of Pará, Belém 66095-663, Brazil
| | - José Wilson Rosa Junior
- Department of Arbovirology and Hemorrhagic Fevers, Evandro Chagas Institute—IEC/MS/SVSA, Ananindeua 67030-000, Brazil
| | | | - Bruna Laís Sena do Nascimento
- Department of Arbovirology and Hemorrhagic Fevers, Evandro Chagas Institute—IEC/MS/SVSA, Ananindeua 67030-000, Brazil
| | - Lívia Caricio Martins
- Department of Arbovirology and Hemorrhagic Fevers, Evandro Chagas Institute—IEC/MS/SVSA, Ananindeua 67030-000, Brazil
| | - Joaquim Pinto Nunes Neto
- Department of Arbovirology and Hemorrhagic Fevers, Evandro Chagas Institute—IEC/MS/SVSA, Ananindeua 67030-000, Brazil
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Reporter Flaviviruses as Tools to Demonstrate Homologous and Heterologous Superinfection Exclusion. Viruses 2022; 14:v14071501. [PMID: 35891480 PMCID: PMC9317482 DOI: 10.3390/v14071501] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Revised: 07/05/2022] [Accepted: 07/06/2022] [Indexed: 12/29/2022] Open
Abstract
Binjari virus (BinJV) is a lineage II or dual-host affiliated insect-specific flavivirus previously demonstrated as replication-deficient in vertebrate cells. Previous studies have shown that BinJV is tolerant to exchanging its structural proteins (prM-E) with pathogenic flaviviruses, making it a safe backbone for flavivirus vaccines. Here, we report generation by circular polymerase extension reaction of BinJV expressing zsGreen or mCherry fluorescent protein. Recovered BinJV reporter viruses grew to high titres (107−8 FFU/mL) in Aedes albopictus C6/36 cells assayed using immunoplaque assays (iPA). We also demonstrate that BinJV reporters could be semi-quantified live in vitro using a fluorescence microplate reader with an observed linear correlation between quantified fluorescence of BinJV reporter virus-infected C6/36 cells and iPA-quantitated virus titres. The utility of the BinJV reporter viruses was then examined in homologous and heterologous superinfection exclusion assays. We demonstrate that primary infection of C6/36 cells with BinJVzsGreen completely inhibits a secondary infection with homologous BinJVmCherry or heterologous ZIKVmCherry using fluorescence microscopy and virus quantitation by iPA. Finally, BinJVzsGreen infections were examined in vivo by microinjection of Aedes aegypti with BinJVzsGreen. At seven days post-infection, a strong fluorescence in the vicinity of salivary glands was detected in frozen sections. This is the first report on the construction of reporter viruses for lineage II insect-specific flaviviruses and establishes a tractable system for exploring flavivirus superinfection exclusion in vitro and in vivo.
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Gloria-Soria A, Brackney DE, Armstrong PM. Saliva collection via capillary method may underestimate arboviral transmission by mosquitoes. Parasit Vectors 2022; 15:103. [PMID: 35331315 PMCID: PMC8944160 DOI: 10.1186/s13071-022-05198-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Accepted: 02/12/2022] [Indexed: 11/24/2022] Open
Abstract
BACKGROUND Arthropod-borne viruses (arboviruses) impose a major health and economic burden on human populations globally, with mosquitoes serving as important vectors. Measuring the ability of a mosquito population to transmit an arbovirus is important in terms of evaluating its public health risk. In the laboratory, a variety of methods are used to estimate arboviral transmission by mosquitoes, including indirect methods involving viral detection from mosquito saliva collected by forced salivation. The accuracy of indirect methods to estimate arbovirus transmission to live animal hosts has not been fully evaluated. METHODS We compared three commonly used proxies of arboviral transmission, namely, the presence of virus in mosquito legs, in salivary glands (SG) and in saliva collected in capillary tubes using forced salivation, with direct transmission estimates from mosquitoes to suckling mice. We analyzed five vector-virus combinations, including Aedes aegypti infected with chikungunya virus, West Nile virus and Zika virus; Culex quinquefasciatus infected with West Nile virus; and Aedes triseriatus infected with La Crosse virus. RESULTS Comparatively, the methods of detecting virus infection in mosquito legs and in SG were equally accurate in predicting transmission. Overall, the presence of virus in mosquito legs was a more accurate predictor of transmission than the commonly implemented viral detection method using forced salivation into a capillary tube, and was subject to less technical variation. CONCLUSIONS These results suggest that, in general, forced salivation methods tend to underestimate virus transmission, and they provide confidence in the use of mosquito leg screens to evaluate the transmission potential of a mosquito population.
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Affiliation(s)
- A. Gloria-Soria
- Center for Vector Biology & Zoonotic Diseases, Department of Environmental Sciences, The Connecticut Agricultural Experiment Station, 123 Huntington St., New Haven, CT 06504 USA
| | - D. E. Brackney
- Center for Vector Biology & Zoonotic Diseases, Department of Environmental Sciences, The Connecticut Agricultural Experiment Station, 123 Huntington St., New Haven, CT 06504 USA
| | - P. M. Armstrong
- Center for Vector Biology & Zoonotic Diseases, Department of Environmental Sciences, The Connecticut Agricultural Experiment Station, 123 Huntington St., New Haven, CT 06504 USA
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Chen P, Chen M, Chen Y, Jing X, Zhang N, Zhou X, Li X, Long G, Hao P. Targeted inhibition of Zika virus infection in human cells by CRISPR-Cas13b. Virus Res 2022; 312:198707. [PMID: 35150770 DOI: 10.1016/j.virusres.2022.198707] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Revised: 02/07/2022] [Accepted: 02/08/2022] [Indexed: 12/26/2022]
Abstract
Zika virus (ZIKV) outbreaks occurred in recent years on an unprecedented scale, which caused fever and severe complications like Guillain-Barré syndrome in adults and fetal abnormalities. No vaccines or other effective treatments against ZIKV are available to date. The CRISPR-Cas13 family has the unique ability to target single-strand RNA molecules and mediate RNA cleavage. In the present study, we sought to exploit CRISPR-Cas13b for developing an anti-ZIKV system in mammalian cells. We first generated a ZIKV infection and reporting system by: 1) fusing mCherry to the ZIKV capsid protein for reporting infection by fluorescence; and 2) deriving a 293T cell line (293T-DC-SIGN) stably expressing DC-SIGN (Dendritic cell-specific intercellular adhesion molecule-3-grabbing non-integrin) that became highly susceptible to ZIKV infection. The CRISPR Cas13b expression was reported to be in the cytoplasm of 293T-DC-SIGN cells using a Cas13b-GFP fusion expression vector. Fourteen CRISPR RNAs (crRNAs) were designed to target the most conserved regions of the ZIKV genome through bioinformatics analysis of 1138 ZIKV genome sequences. Five crRNAs were found to have significant effects (p < 0.001; two-sided t test) for Cas13b-targeted inhibition on ZIKV infection in 293T-DC-SIGN cells. Our study demonstrated an exciting example of using the CRISPR-Cas13b system for the treatment and prevention of ZIKV infection, highlighting CRISPR-Cas13 as a promising therapeutic anti-RNA virus strategy.
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Affiliation(s)
- Ping Chen
- The Joint Program in Infection and Immunity. a. Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou 510623, China; Institute Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai 200031, China
| | - Minjie Chen
- Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, 200032, China
| | - Yujie Chen
- The Joint Program in Infection and Immunity. a. Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou 510623, China
| | - Xinyun Jing
- Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, 200032, China
| | - Niubing Zhang
- Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, 200032, China
| | - Xiaojuan Zhou
- Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, 200032, China
| | - Xuan Li
- Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, 200032, China
| | - Gang Long
- The Joint Program in Infection and Immunity. a. Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou 510623, China; Institute Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai 200031, China
| | - Pei Hao
- The Joint Program in Infection and Immunity. a. Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou 510623, China; Institute Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai 200031, China.
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6
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Wessel AW, Dowd KA, Biering SB, Zhang P, Edeling MA, Nelson CA, Funk KE, DeMaso CR, Klein RS, Smith JL, Cao TM, Kuhn RJ, Fremont DH, Harris E, Pierson TC, Diamond MS. Levels of Circulating NS1 Impact West Nile Virus Spread to the Brain. J Virol 2021; 95:e0084421. [PMID: 34346770 PMCID: PMC8475509 DOI: 10.1128/jvi.00844-21] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2021] [Accepted: 07/28/2021] [Indexed: 12/15/2022] Open
Abstract
Dengue virus (DENV) and West Nile virus (WNV) are arthropod-transmitted flaviviruses that cause systemic vascular leakage and encephalitis syndromes, respectively, in humans. However, the viral factors contributing to these specific clinical disorders are not completely understood. Flavivirus nonstructural protein 1 (NS1) is required for replication, expressed on the cell surface, and secreted as a soluble glycoprotein, reaching high levels in the blood of infected individuals. Extracellular DENV NS1 and WNV NS1 interact with host proteins and cells, have immune evasion functions, and promote endothelial dysfunction in a tissue-specific manner. To characterize how differences in DENV NS1 and WNV NS1 might function in pathogenesis, we generated WNV NS1 variants with substitutions corresponding to residues found in DENV NS1. We discovered that the substitution NS1-P101K led to reduced WNV infectivity in the brain and attenuated lethality in infected mice, although the virus replicated efficiently in cell culture and peripheral organs and bound at wild-type levels to brain endothelial cells and complement components. The P101K substitution resulted in reduced NS1 antigenemia in mice, and this was associated with reduced WNV spread to the brain. Because exogenous administration of NS1 protein rescued WNV brain infectivity in mice, we conclude that circulating WNV NS1 facilitates viral dissemination into the central nervous system and impacts disease outcomes. IMPORTANCE Flavivirus NS1 serves as an essential scaffolding molecule during virus replication but also is expressed on the cell surface and is secreted as a soluble glycoprotein that circulates in the blood of infected individuals. Although extracellular forms of NS1 are implicated in immune modulation and in promoting endothelial dysfunction at blood-tissue barriers, it has been challenging to study specific effects of NS1 on pathogenesis without disrupting its key role in virus replication. Here, we assessed WNV NS1 variants that do not affect virus replication and evaluated their effects on pathogenesis in mice. Our characterization of WNV NS1-P101K suggests that the levels of NS1 in the circulation facilitate WNV dissemination to the brain and affect disease outcomes. Our findings facilitate understanding of the role of NS1 during flavivirus infection and support antiviral strategies for targeting circulating forms of NS1.
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Affiliation(s)
- Alex W. Wessel
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri, USA
- Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Kimberly A. Dowd
- Viral Pathogenesis Section, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Scott B. Biering
- Division of Infectious Diseases and Vaccinology, School of Public Health, University of California, Berkeley, Berkeley, California, USA
| | - Ping Zhang
- Department of Immunology, Key Laboratory of Tropical Diseases Control, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China
| | - Melissa A. Edeling
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Christopher A. Nelson
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Kristen E. Funk
- Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Christina R. DeMaso
- Viral Pathogenesis Section, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Robyn S. Klein
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri, USA
- Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
- Department of Neuroscience, Washington University School of Medicine, St. Louis, Missouri, USA
- Center for Neuroimmunology and Neuroinfectious Diseases, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Janet L. Smith
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan, USA
- Department of Biological Chemistry, University of Michigan, Ann Arbor, Michigan, USA
| | - Thu Minh Cao
- Department of Biological Sciences, Purdue University, West Lafayette, Indiana, USA
- Purdue Institute of Inflammation, Immunology, and Infectious Disease, Purdue University, West Lafayette, Indiana, USA
| | - Richard J. Kuhn
- Department of Biological Sciences, Purdue University, West Lafayette, Indiana, USA
- Purdue Institute of Inflammation, Immunology, and Infectious Disease, Purdue University, West Lafayette, Indiana, USA
| | - Daved H. Fremont
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri, USA
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, USA
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Eva Harris
- Division of Infectious Diseases and Vaccinology, School of Public Health, University of California, Berkeley, Berkeley, California, USA
| | - Theodore C. Pierson
- Viral Pathogenesis Section, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Michael S. Diamond
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri, USA
- Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, USA
- The Andrew M. and Jane M. Bursky Center for Human Immunology and Immunotherapy Programs, Washington University School of Medicine, St. Louis, Missouri, USA
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Hoffmann HH, Schneider WM, Rozen-Gagnon K, Miles LA, Schuster F, Razooky B, Jacobson E, Wu X, Yi S, Rudin CM, MacDonald MR, McMullan LK, Poirier JT, Rice CM. TMEM41B Is a Pan-flavivirus Host Factor. Cell 2021; 184:133-148.e20. [PMID: 33338421 PMCID: PMC7954666 DOI: 10.1016/j.cell.2020.12.005] [Citation(s) in RCA: 104] [Impact Index Per Article: 34.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Revised: 11/13/2020] [Accepted: 12/02/2020] [Indexed: 12/12/2022]
Abstract
Flaviviruses pose a constant threat to human health. These RNA viruses are transmitted by the bite of infected mosquitoes and ticks and regularly cause outbreaks. To identify host factors required for flavivirus infection, we performed full-genome loss of function CRISPR-Cas9 screens. Based on these results, we focused our efforts on characterizing the roles that TMEM41B and VMP1 play in the virus replication cycle. Our mechanistic studies on TMEM41B revealed that all members of the Flaviviridae family that we tested require TMEM41B. We tested 12 additional virus families and found that SARS-CoV-2 of the Coronaviridae also required TMEM41B for infection. Remarkably, single nucleotide polymorphisms present at nearly 20% in East Asian populations reduce flavivirus infection. Based on our mechanistic studies, we propose that TMEM41B is recruited to flavivirus RNA replication complexes to facilitate membrane curvature, which creates a protected environment for viral genome replication.
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Affiliation(s)
- H-Heinrich Hoffmann
- Laboratory of Virology and Infectious Disease, The Rockefeller University, New York, NY, USA
| | - William M Schneider
- Laboratory of Virology and Infectious Disease, The Rockefeller University, New York, NY, USA
| | - Kathryn Rozen-Gagnon
- Laboratory of Virology and Infectious Disease, The Rockefeller University, New York, NY, USA
| | - Linde A Miles
- Human Oncology & Pathogenesis Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Felix Schuster
- Laboratory of Virology and Infectious Disease, The Rockefeller University, New York, NY, USA; Institute of Virology, Medical Faculty "Carl Gustav Carus", Technische Universität Dresden, Dresden, Germany
| | - Brandon Razooky
- Laboratory of Virology and Infectious Disease, The Rockefeller University, New York, NY, USA
| | - Eliana Jacobson
- Laboratory of Virology and Infectious Disease, The Rockefeller University, New York, NY, USA
| | - Xianfang Wu
- Laboratory of Virology and Infectious Disease, The Rockefeller University, New York, NY, USA
| | - Soon Yi
- Laboratory of Virology and Infectious Disease, The Rockefeller University, New York, NY, USA
| | - Charles M Rudin
- Druckenmiller Center for Lung Cancer Research and Department of Medicine, Thoracic Oncology Service, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Margaret R MacDonald
- Laboratory of Virology and Infectious Disease, The Rockefeller University, New York, NY, USA
| | - Laura K McMullan
- Virus Special Pathogens Branch, Division of High Consequence Pathogens and Pathology, Centers of Disease Control and Prevention, Atlanta, GA, USA
| | - John T Poirier
- Laura and Isaac Perlmutter Cancer Center, New York University Langone Health, New York, NY, USA.
| | - Charles M Rice
- Laboratory of Virology and Infectious Disease, The Rockefeller University, New York, NY, USA.
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8
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Hoffmann HH, Schneider WM, Rozen-Gagnon K, Miles LA, Schuster F, Razooky B, Jacobson E, Wu X, Yi S, Rudin CM, MacDonald MR, McMullan LK, Poirier JT, Rice CM. TMEM41B is a pan-flavivirus host factor. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2020:2020.10.09.334128. [PMID: 33052348 PMCID: PMC7553181 DOI: 10.1101/2020.10.09.334128] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Flaviviruses pose a constant threat to human health. These RNA viruses are transmitted by the bite of infected mosquitoes and ticks and regularly cause outbreaks. To identify host factors required for flavivirus infection we performed full-genome loss of function CRISPR-Cas9 screens. Based on these results we focused our efforts on characterizing the roles that TMEM41B and VMP1 play in the virus replication cycle. Our mechanistic studies on TMEM41B revealed that all members of the Flaviviridae family that we tested require TMEM41B. We tested 12 additional virus families and found that SARS-CoV-2 of the Coronaviridae also required TMEM41B for infection. Remarkably, single nucleotide polymorphisms (SNPs) present at nearly twenty percent in East Asian populations reduce flavivirus infection. Based on our mechanistic studies we hypothesize that TMEM41B is recruited to flavivirus RNA replication complexes to facilitate membrane curvature, which creates a protected environment for viral genome replication. HIGHLIGHTS TMEM41B and VMP1 are required for both autophagy and flavivirus infection, however, autophagy is not required for flavivirus infection.TMEM41B associates with viral proteins and likely facilitates membrane remodeling to establish viral RNA replication complexes.TMEM41B single nucleotide polymorphisms (SNPs) present at nearly twenty percent in East Asian populations reduce flavivirus infection.TMEM41B-deficient cells display an exaggerated innate immune response upon high multiplicity flavivirus infection.
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Affiliation(s)
- H-Heinrich Hoffmann
- Laboratory of Virology and Infectious Disease, The Rockefeller University, New York, NY, USA
| | - William M Schneider
- Laboratory of Virology and Infectious Disease, The Rockefeller University, New York, NY, USA
| | - Kathryn Rozen-Gagnon
- Laboratory of Virology and Infectious Disease, The Rockefeller University, New York, NY, USA
| | - Linde A Miles
- Human Oncology & Pathogenesis Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Felix Schuster
- Laboratory of Virology and Infectious Disease, The Rockefeller University, New York, NY, USA
- Institute of Virology, Medical Faculty "Carl Gustav Carus", Technische Universität Dresden, Dresden, Germany
| | - Brandon Razooky
- Laboratory of Virology and Infectious Disease, The Rockefeller University, New York, NY, USA
| | - Eliana Jacobson
- Laboratory of Virology and Infectious Disease, The Rockefeller University, New York, NY, USA
| | - Xianfang Wu
- Laboratory of Virology and Infectious Disease, The Rockefeller University, New York, NY, USA
| | - Soon Yi
- Laboratory of Virology and Infectious Disease, The Rockefeller University, New York, NY, USA
| | - Charles M Rudin
- Druckenmiller Center for Lung Cancer Research and Department of Medicine, Thoracic Oncology Service, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Margaret R MacDonald
- Laboratory of Virology and Infectious Disease, The Rockefeller University, New York, NY, USA
| | - Laura K McMullan
- Virus Special Pathogens Branch, Division of High Consequence Pathogens and Pathology, Centers of Disease Control and Prevention, Atlanta, GA, USA
| | - John T Poirier
- Laura and Isaac Perlmutter Cancer Center, New York University Langone Health, New York, NY, USA
| | - Charles M Rice
- Laboratory of Virology and Infectious Disease, The Rockefeller University, New York, NY, USA
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9
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Esswein SR, Gristick HB, Jurado A, Peace A, Keeffe JR, Lee YE, Voll AV, Saeed M, Nussenzweig MC, Rice CM, Robbiani DF, MacDonald MR, Bjorkman PJ. Structural basis for Zika envelope domain III recognition by a germline version of a recurrent neutralizing antibody. Proc Natl Acad Sci U S A 2020; 117:9865-9875. [PMID: 32321830 PMCID: PMC7211955 DOI: 10.1073/pnas.1919269117] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Recent epidemics demonstrate the global threat of Zika virus (ZIKV), a flavivirus transmitted by mosquitoes. Although infection is usually asymptomatic or mild, newborns of infected mothers can display severe symptoms, including neurodevelopmental abnormalities and microcephaly. Given the large-scale spread, symptom severity, and lack of treatment or prophylaxis, a safe and effective ZIKV vaccine is urgently needed. However, vaccine design is complicated by concern that elicited antibodies (Abs) may cross-react with other flaviviruses that share a similar envelope protein, such as dengue virus, West Nile virus, and yellow fever virus. This cross-reactivity may worsen symptoms of a subsequent infection through Ab-dependent enhancement. To better understand the neutralizing Ab response and risk of Ab-dependent enhancement, further information on germline Ab binding to ZIKV and the maturation process that gives rise to potently neutralizing Abs is needed. Here we use binding and structural studies to compare mature and inferred-germline Ab binding to envelope protein domain III of ZIKV and other flaviviruses. We show that affinity maturation of the light-chain variable domain is important for strong binding of the recurrent VH3-23/VK1-5 neutralizing Abs to ZIKV envelope protein domain III, and identify interacting residues that contribute to weak, cross-reactive binding to West Nile virus. These findings provide insight into the affinity maturation process and potential cross-reactivity of VH3-23/VK1-5 neutralizing Abs, informing precautions for protein-based vaccines designed to elicit germline versions of neutralizing Abs.
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Affiliation(s)
- Shannon R Esswein
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125
| | - Harry B Gristick
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125
| | - Andrea Jurado
- Laboratory of Virology and Infectious Disease, The Rockefeller University, New York, NY 10065
| | - Avery Peace
- Laboratory of Virology and Infectious Disease, The Rockefeller University, New York, NY 10065
| | - Jennifer R Keeffe
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125
| | - Yu E Lee
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125
| | - Alisa V Voll
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125
| | - Mohsan Saeed
- Laboratory of Virology and Infectious Disease, The Rockefeller University, New York, NY 10065
| | - Michel C Nussenzweig
- Laboratory of Molecular Immunology, The Rockefeller University, New York, NY 10065
- Howard Hughes Medical Institute, The Rockefeller University, New York, NY 10065
| | - Charles M Rice
- Laboratory of Virology and Infectious Disease, The Rockefeller University, New York, NY 10065
| | - Davide F Robbiani
- Laboratory of Molecular Immunology, The Rockefeller University, New York, NY 10065
| | - Margaret R MacDonald
- Laboratory of Virology and Infectious Disease, The Rockefeller University, New York, NY 10065
| | - Pamela J Bjorkman
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125;
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10
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Pfaender S, Mar KB, Michailidis E, Kratzel A, Hirt D, V'kovski P, Fan W, Ebert N, Stalder H, Kleine-Weber H, Hoffmann M, Hoffmann HH, Saeed M, Dijkman R, Steinmann E, Wight-Carter M, Hanners NW, Pöhlmann S, Gallagher T, Todt D, Zimmer G, Rice CM, Schoggins JW, Thiel V. LY6E impairs coronavirus fusion and confers immune control of viral disease. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2020:2020.03.05.979260. [PMID: 32511345 PMCID: PMC7255780 DOI: 10.1101/2020.03.05.979260] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Zoonotic coronaviruses (CoVs) are significant threats to global health, as exemplified by the recent emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) 1 . Host immune responses to CoV are complex and regulated in part through antiviral interferons. However, the interferon-stimulated gene products that inhibit CoV are not well characterized 2 . Here, we show that interferon-inducible lymphocyte antigen 6 complex, locus E (LY6E) potently restricts cellular infection by multiple CoVs, including SARS-CoV, SARS-CoV-2, and Middle East respiratory syndrome coronavirus (MERS-CoV). Mechanistic studies revealed that LY6E inhibits CoV entry into cells by interfering with spike protein-mediated membrane fusion. Importantly, mice lacking Ly6e in hematopoietic cells were highly susceptible to murine CoV infection. Exacerbated viral pathogenesis in Ly6e knockout mice was accompanied by loss of hepatic and splenic immune cells and reduction in global antiviral gene pathways. Accordingly, we found that Ly6e directly protects primary B cells and dendritic cells from murine CoV infection. Our results demonstrate that LY6E is a critical antiviral immune effector that controls CoV infection and pathogenesis. These findings advance our understanding of immune-mediated control of CoV in vitro and in vivo , knowledge that could help inform strategies to combat infection by emerging CoV.
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11
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Novel Approach for Insertion of Heterologous Sequences into Full-Length ZIKV Genome Results in Superior Level of Gene Expression and Insert Stability. Viruses 2020; 12:v12010061. [PMID: 31947825 PMCID: PMC7019263 DOI: 10.3390/v12010061] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Revised: 12/27/2019] [Accepted: 12/31/2019] [Indexed: 12/15/2022] Open
Abstract
Zika virus (ZIKV) emerged in the Americas in 2015, presenting unique challenges to public health. Unlike other arboviruses of the Flaviviridae family, it is transmissible by sexual contact, which facilitates the spread of the virus into new geographic areas. Additionally, ZIKV can be transmitted from mother to fetus, causing microcephaly and other severe developmental abnormalities. Reliable and easy-to-work-with clones of ZIKV expressing heterologous genes will significantly facilitate studies aimed at understanding the virus pathogenesis and tissue tropism. Here, we developed and characterized two novel approaches for expression of heterologous genes of interest in the context of full-length ZIKV genome and compared them to two previously published strategies for ZIKV-mediated gene expression. We demonstrated that among the four tested viruses expressing nLuc gene, the virus constructed using a newly developed approach of partial capsid gene duplication (PCGD) attained the highest titer in Vero cells and resulted in the highest level of nLuc expression. Suitability of the PCGD approach for expression of different genes of interest was validated by replacing nLuc sequence with that of eGFP gene. The generated constructs were further characterized in cell culture. Potential applications of ZIKV clones stably expressing heterologous genes include development of detection assays, antivirals, therapeutics, live imaging systems, and vaccines.
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12
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Development of Stable Rotavirus Reporter Expression Systems. J Virol 2019; 93:JVI.01774-18. [PMID: 30541830 DOI: 10.1128/jvi.01774-18] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Accepted: 11/27/2018] [Indexed: 01/22/2023] Open
Abstract
Engineered recombinant viruses expressing reporter genes have been developed for real-time monitoring of replication and for mass screening of antiviral inhibitors. Recently, we reported using a reverse genetics system to develop the first recombinant reporter rotaviruses (RVs) that expressed NanoLuc (NLuc) luciferase. Here, we describe a strategy for developing stable reporter RVs expressing luciferase and green or red fluorescent proteins. The reporter genes were inserted into the open reading frame of NSP1 and expressed as a fusion with an NSP1 peptide consisting of amino acids 1 to 27. The stability of foreign genes within the reporter RV strains harboring a shorter chimeric NSP1-reporter gene was greater than that of those in the original reporter RV strain, independent of the transgene inserted. The improved reporter RV was used to screen for neutralizing monoclonal antibodies (MAbs). Sequence analysis of escape mutants from one MAb clone (clone 29) identified an amino acid substitution (arginine to glycine) at position 441 in the VP4 protein, which resides within neutralizing epitope 5-1 in the VP5* fragment. Furthermore, to express a native reporter protein lacking NSP1 amino acids 1 to 27, the 5'- and 3'-terminal region sequences were modified to restore the predicted secondary RNA structure of the NSP1-reporter chimeric gene. These data demonstrate the utility of reporter RVs for live monitoring of RV infections and also suggest further applications (e.g., RV vaccine vectors, which can induce mucosal immunity against intestinal pathogens).IMPORTANCE Development of reporter RVs has been hampered by the lack of comprehensive reverse genetics systems. Recently, we developed a plasmid-based reverse genetics system that enables generation of reporter RVs expressing NLuc luciferase. The prototype reporter RV had some disadvantages (i.e., the transgene was unstable and was expressed as a fusion protein with a partial NSP1 peptide); however, the improved reporter RV overcomes these problems through modification of the untranslated region of the reporter-NSP1 chimeric gene. This strategy for generating stable reporter RVs could be expanded to diverse transgenes and be used to develop RV transduction vectors. Also, the data improve our understanding of the importance of 5'- and 3'-terminal sequences in terms of genome replication, assembly, and packaging.
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13
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Spence JS, He R, Hoffmann HH, Das T, Thinon E, Rice CM, Peng T, Chandran K, Hang HC. IFITM3 directly engages and shuttles incoming virus particles to lysosomes. Nat Chem Biol 2019; 15:259-268. [PMID: 30643282 PMCID: PMC6466627 DOI: 10.1038/s41589-018-0213-2] [Citation(s) in RCA: 147] [Impact Index Per Article: 29.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Accepted: 12/03/2018] [Indexed: 12/16/2022]
Abstract
Interferon-induced transmembrane proteins (IFITMs 1, 2 and 3) have emerged as important innate immune effectors that prevent diverse virus infections in vertebrates. However, the cellular mechanisms and live-cell imaging of these small membrane proteins have been challenging to evaluate during viral entry of mammalian cells. Using CRISPR–Cas9-mediated IFITM-mutant cell lines, we demonstrate that human IFITM1, IFITM2 and IFITM3 act cooperatively and function in a dose-dependent fashion in interferon-stimulated cells. Through site-specific fluorophore tagging and live-cell imaging studies, we show that IFITM3 is on endocytic vesicles that fuse with incoming virus particles and enhances the trafficking of this pathogenic cargo to lysosomes. IFITM3 trafficking is specific to restricted viruses, requires S-palmitoylation and is abrogated with loss-of-function mutants. The site-specific protein labeling and live-cell imaging approaches described here should facilitate the functional analysis of host factors involved in pathogen restriction as well as their mechanisms of regulation. Live-cell imaging and virus trafficking studies show that the host innate immune receptor IFITM3 localizes with endocytic vesicles that fuse with incoming viruses to ultimately enhance their traffic to lysosomes.![]()
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Affiliation(s)
- Jennifer S Spence
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Ruina He
- Laboratory of Chemical Biology and Microbial Pathogenesis, The Rockefeller University, New York, NY, USA
| | - Hans-Heinrich Hoffmann
- Laboratory of Virology and Infectious Disease, Center for the Study of Hepatitis C, The Rockefeller University, New York, NY, USA
| | - Tandrila Das
- Laboratory of Chemical Biology and Microbial Pathogenesis, The Rockefeller University, New York, NY, USA
| | - Emmanuelle Thinon
- Laboratory of Chemical Biology and Microbial Pathogenesis, The Rockefeller University, New York, NY, USA
| | - Charles M Rice
- Laboratory of Virology and Infectious Disease, Center for the Study of Hepatitis C, The Rockefeller University, New York, NY, USA
| | - Tao Peng
- Laboratory of Chemical Biology and Microbial Pathogenesis, The Rockefeller University, New York, NY, USA. .,School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School, Shenzhen, China.
| | - Kartik Chandran
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY, USA.
| | - Howard C Hang
- Laboratory of Chemical Biology and Microbial Pathogenesis, The Rockefeller University, New York, NY, USA.
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14
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Probing Zika Virus Neutralization Determinants with Glycoprotein Mutants Bearing Linear Epitope Insertions. J Virol 2018; 92:JVI.00505-18. [PMID: 29976678 DOI: 10.1128/jvi.00505-18] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2018] [Accepted: 07/02/2018] [Indexed: 01/13/2023] Open
Abstract
Zika virus (ZIKV) glycoproteins are the primary target of the humoral immune response. In this study, we explored the capacity of these glycoproteins to tolerate insertion of linear epitope sequences and the potential of antibodies that bind these epitopes to inhibit infection. We first created a panel of ZIKV mutants with the FLAG epitope inserted in the premembrane (prM) and envelope (E) glycoprotein regions. The insertion locations were based on the results of our recent transposon insertional mutagenesis screen. Although FLAG insertions in prM greatly impaired viral fitness, this sequence was tolerated in numerous surface-exposed E protein sites. We observed that mutants bearing FLAG epitopes in E domains I and II and the E domain I-II hinge region were all neutralized by FLAG antibody; however, the neutralization sensitivity varied highly. We measured the antibody binding efficiency and found that this closely matched the pattern of neutralization sensitivity. We determined that E glycosylation did not affect antibody binding to a nearby epitope or its capacity to serve as a neutralization target. Although we could not generate infectious viruses with FLAG epitope insertions in a buried region of E protein domain III, we found that the V5 epitope could be inserted at this site without greatly impacting fitness. Furthermore, this virus was efficiently neutralized by V5 antibodies, highlighting that even buried epitopes can function as neutralization targets. Finally, we analyzed the timing of antibody neutralization activity during cell entry and found that all antibodies blocked a step after cell attachment.IMPORTANCE Zika virus (ZIKV) infections are associated with severe birth defects and neurological disease. The structure of the mature ZIKV particle reveals a virion surface covered by the envelope glycoprotein, which is the dominant target of the humoral immune response. It is unclear if all regions of the envelope protein surface or even buried epitopes can function as neutralization targets. To test this, we created a panel of ZIKV mutants with epitope insertions in different regions of the envelope protein. In characterizing these viruses, we found that the strength of antibody binding to an epitope is the major determinant of the neutralization potential of an antibody, that even a buried region of the envelope protein can be efficiently targeted, and that the sole potential envelope glycan does not impact nearby epitope antibody binding and neutralization. Furthermore, this work provides important insights into our understanding of how antibodies neutralize ZIKV.
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15
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Hoffmann HH, Schneider WM, Blomen VA, Scull MA, Hovnanian A, Brummelkamp TR, Rice CM. Diverse Viruses Require the Calcium Transporter SPCA1 for Maturation and Spread. Cell Host Microbe 2018; 22:460-470.e5. [PMID: 29024641 DOI: 10.1016/j.chom.2017.09.002] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Revised: 07/05/2017] [Accepted: 09/06/2017] [Indexed: 10/18/2022]
Abstract
Respiratory and arthropod-borne viral infections are a global threat due to the lack of effective antivirals and vaccines. A potential strategy is to target host proteins required for viruses but non-essential for the host. To identify such proteins, we performed a genome-wide knockout screen in human haploid cells and identified the calcium pump SPCA1. SPCA1 is required by viruses from the Paramyxoviridae, Flaviviridae, and Togaviridae families, including measles, dengue, West Nile, Zika, and chikungunya viruses. Calcium transport activity is required for SPCA1 to promote virus spread. SPCA1 regulates proteases within the trans-Golgi network that require calcium for their activity and are critical for virus glycoprotein maturation. Consistent with these findings, viral glycoproteins fail to mature in SPCA1-deficient cells preventing viral spread, which is evident even in cells with partial loss of SPCA1. Thus, SPCA1 is an attractive antiviral host target for a broad spectrum of established and emerging viral infections.
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Affiliation(s)
- H-Heinrich Hoffmann
- Laboratory of Virology and Infectious Disease, The Rockefeller University, New York, NY 10065, USA
| | - William M Schneider
- Laboratory of Virology and Infectious Disease, The Rockefeller University, New York, NY 10065, USA
| | - Vincent A Blomen
- Biochemistry Division, Netherlands Cancer Institute, 1066 CX Amsterdam, The Netherlands
| | - Margaret A Scull
- Laboratory of Virology and Infectious Disease, The Rockefeller University, New York, NY 10065, USA
| | - Alain Hovnanian
- INSERM UMR 1163 and Imagine Institute, 75015 Paris, France; Université Paris V Descartes - Sorbonne Paris Cité, 75006 Paris, France; Department of Genetics, Necker Hospital, 75015 Paris, France
| | - Thijn R Brummelkamp
- Biochemistry Division, Netherlands Cancer Institute, 1066 CX Amsterdam, The Netherlands; Cancer Genomics Centre, 3584 CG Utrecht, The Netherlands
| | - Charles M Rice
- Laboratory of Virology and Infectious Disease, The Rockefeller University, New York, NY 10065, USA.
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16
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Infection dynamics of Nosema ceranae in honey bee midgut and host cell apoptosis. J Invertebr Pathol 2018; 154:1-4. [PMID: 29550404 DOI: 10.1016/j.jip.2018.03.008] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2017] [Revised: 02/24/2018] [Accepted: 03/13/2018] [Indexed: 11/22/2022]
Abstract
Nosema ceranae is an intracellular microsporidian parasite that infects epithelial cells of the honey bee (Apis mellifera) midgut. Previous studies have shown that Nosema may alter cell renewal and apoptosis in honey bees. We found that the amount of apoptotic cells progressively declines from the anterior towards posterior regions of the midgut in Nosema-infected sensitive bees. There was no such pattern in the infected Nosema tolerant honey bees and controls. These data provide additional evidence that N. ceranae appears to alter apoptosis in its host cells for its own advantage.
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17
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Vogels CB, Göertz GP, Pijlman GP, Koenraadt CJ. Vector competence of European mosquitoes for West Nile virus. Emerg Microbes Infect 2017; 6:e96. [PMID: 29116220 PMCID: PMC5717085 DOI: 10.1038/emi.2017.82] [Citation(s) in RCA: 73] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Revised: 08/23/2017] [Accepted: 08/27/2017] [Indexed: 01/02/2023]
Abstract
West Nile virus (WNV) is an arthropod-borne flavivirus of high medical and veterinary importance. The main vectors for WNV are mosquito species of the Culex genus that transmit WNV among birds, and occasionally to humans and horses, which are ‘dead-end’ hosts. Recently, several studies have been published that aimed to identify the mosquito species that serve as vectors for WNV in Europe. These studies provide insight in factors that can influence vector competence of European mosquito species for WNV. Here, we review the current knowledge on vector competence of European mosquitoes for WNV, and the molecular knowledge on physical barriers, anti-viral pathways and microbes that influence vector competence based on studies with other flaviviruses. By comparing the 12 available WNV vector competence studies with European mosquitoes we evaluate the effect of factors such as temperature, mosquito origin and mosquito biotype on vector competence. In addition, we propose a standardised methodology to allow for comparative studies across Europe. Finally, we identify knowledge gaps regarding vector competence that, once addressed, will provide important insights into WNV transmission and ultimately contribute to effective strategies to control WNV.
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Affiliation(s)
- Chantal Bf Vogels
- Laboratory of Entomology, Wageningen University & Research, P.O. Box 16, 6700 AA, Wageningen, The Netherlands
| | - Giel P Göertz
- Laboratory of Virology, Wageningen University & Research, P.O. Box 16, 6700 AA, Wageningen, The Netherlands
| | - Gorben P Pijlman
- Laboratory of Virology, Wageningen University & Research, P.O. Box 16, 6700 AA, Wageningen, The Netherlands
| | - Constantianus Jm Koenraadt
- Laboratory of Entomology, Wageningen University & Research, P.O. Box 16, 6700 AA, Wageningen, The Netherlands
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18
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Mutso M, Saul S, Rausalu K, Susova O, Žusinaite E, Mahalingam S, Merits A. Reverse genetic system, genetically stable reporter viruses and packaged subgenomic replicon based on a Brazilian Zika virus isolate. J Gen Virol 2017; 98:2712-2724. [PMID: 29022864 DOI: 10.1099/jgv.0.000938] [Citation(s) in RCA: 74] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Zika virus (ZIKV, genus Flavivirus) has emerged as a major mosquito-transmitted human pathogen, with recent outbreaks associated with an increased incidence of neurological complications, particularly microcephaly and the Guillain-Barré syndrome. Because the virus has only very recently emerged as an important pathogen, research is being hampered by a lack of reliable molecular tools. Here we report an infectious cDNA (icDNA) clone for ZIKV isolate BeH819015 from Brazil, which was selected as representative of South American ZIKV isolated at early stages of the outbreak. icDNA clones were assembled from synthetic DNA fragments corresponding to the consensus sequence of the BeH819015 isolate. Virus rescued from the icDNA clone had properties identical to a natural ZIKV isolate from South America. Variants of the clone-derived virus, expressing nanoluciferase, enhanced green fluorescent or mCherry marker proteins in both mammalian and insect cells and being genetically stable for multiple in vitro passages, were obtained. A ZIKV subgenomic replicon, lacking a prM- and E glycoprotein encoding region and expressing a Gaussia luciferase marker, was constructed and shown to replicate both in mammalian and insect cells. In the presence of the Semliki Forest virus replicon, expressing ZIKV structural proteins, the ZIKV replicon was packaged into virus-replicon particles. Efficient reverse genetic systems, genetically stable marker viruses and packaged replicons offer significant improvements for biological studies of ZIKV infection and disease, as well as for the development of antiviral approaches.
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Affiliation(s)
- Margit Mutso
- Institute of Technology, University of Tartu, Tartu, Estonia.,Institute for Glycomics, Griffith University, Gold Coast Campus, Southport, 4222, Queensland, Australia
| | - Sirle Saul
- Institute of Technology, University of Tartu, Tartu, Estonia
| | - Kai Rausalu
- Institute of Technology, University of Tartu, Tartu, Estonia
| | - Olga Susova
- Blokhin Russian Cancer Research Center, Ministry of Health of the Russian Federation, Moscow, 115487, Russia
| | - Eva Žusinaite
- Institute of Technology, University of Tartu, Tartu, Estonia
| | - Suresh Mahalingam
- Institute for Glycomics, Griffith University, Gold Coast Campus, Southport, 4222, Queensland, Australia
| | - Andres Merits
- Institute of Technology, University of Tartu, Tartu, Estonia
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19
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Dengue Virus Hijacks a Noncanonical Oxidoreductase Function of a Cellular Oligosaccharyltransferase Complex. mBio 2017; 8:mBio.00939-17. [PMID: 28720733 PMCID: PMC5516256 DOI: 10.1128/mbio.00939-17] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Dengue virus (DENV) is the most common arboviral infection globally, infecting an estimated 390 million people each year. We employed a genome-wide clustered regularly interspaced short palindromic repeat (CRISPR) screen to identify host dependency factors required for DENV propagation and identified the oligosaccharyltransferase (OST) complex as an essential host factor for DENV infection. Mammalian cells express two OSTs containing either STT3A or STT3B. We found that the canonical catalytic function of the OSTs as oligosaccharyltransferases is not necessary for DENV infection, as cells expressing catalytically inactive STT3A or STT3B are able to support DENV propagation. However, the OST subunit MAGT1, which associates with STT3B, is also required for DENV propagation. MAGT1 expression requires STT3B, and a catalytically inactive STT3B also rescues MAGT1 expression, supporting the hypothesis that STT3B serves to stabilize MAGT1 in the context of DENV infection. We found that the oxidoreductase CXXC active site motif of MAGT1 was necessary for DENV propagation, as cells expressing an AXXA MAGT1 mutant were unable to support DENV infection. Interestingly, cells expressing single-cysteine CXXA or AXXC mutants of MAGT1 were able to support DENV propagation. Utilizing the engineered peroxidase APEX2, we demonstrate the close proximity between MAGT1 and NS1 or NS4B during DENV infection. These results reveal that the oxidoreductase activity of the STT3B-containing OST is necessary for DENV infection, which may guide the development of antiviral agents targeting DENV. The host oligosaccharyltransferase (OST) complexes have been identified as essential host factors for dengue virus (DENV) replication; however, their functions during DENV infection are unclear. A previous study showed that the canonical OST activity was dispensable for DENV replication, suggesting that the OST complexes serve as scaffolds for DENV replication. However, our work demonstrates that one function of the OST complex during DENV infection is to provide oxidoreductase activity via the OST subunit MAGT1. We also show that MAGT1 associates with DENV NS1 and NS4B during viral infection, suggesting that these nonstructural proteins may be targets of MAGT1 oxidoreductase activity. These results provide insight into the cell biology of DENV infection, which may guide the development of antivirals against DENV.
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20
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Differential Infectivities among Different Japanese Encephalitis Virus Genotypes in Culex quinquefasciatus Mosquitoes. PLoS Negl Trop Dis 2016; 10:e0005038. [PMID: 27706157 PMCID: PMC5051684 DOI: 10.1371/journal.pntd.0005038] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Accepted: 09/13/2016] [Indexed: 12/29/2022] Open
Abstract
During the last 20 years, the epidemiology of Japanese encephalitis virus (JEV) has changed significantly in its endemic regions due to the gradual displacement of the previously dominant genotype III (GIII) with clade b of GI (GI-b). Whilst there is only limited genetic difference distinguishing the two GI clades (GI-a and GI-b), GI-b has shown a significantly wider and more rapid dispersal pattern in several regions in Asia than the GI-a clade, which remains restricted in its geographic distribution since its emergence. Although previously published molecular epidemiological evidence has shown distinct phylodynamic patterns, characterization of the two GI clades has only been limited to in vitro studies. In this study, Culex quinquefasciatus, a known competent JEV mosquito vector species, was orally challenged with three JEV strains each representing GI-a, GI-b, and GIII, respectively. Infection and dissemination were determined based on the detection of infectious viruses in homogenized mosquitoes. Detection of JEV RNA in mosquito saliva at 14 days post infection indicated that Cx. quinquefasciatus can be a competent vector species for both GI and GIII strains. Significantly higher infection rates in mosquitoes exposed to the GI-b and GIII strains than the GI-a strain suggest infectivity in arthropod vectors may lead to the selective advantage of previously and currently dominant genotypes. It could thus play a role in enzootic transmission cycles for the maintenance of JEV if this virus were ever to be introduced into North America. Japanese encephalitis virus (JEV) is a zoonotic flavivirus, which is primarily transmitted by Culex species mosquitoes and a leading cause of pediatric encephalitis in Asia. JEV is also an important public health threat to countries outside the endemic region because collections of Cx. quinquefasciatus from around the world have demonstrated competence for the transmission of JEV and are capable of establishing enzootic transmission cycles between viremic avian and swine species. In the last two decades, the dominantly circulating genotype of JEV in endemic regions has experienced a significant shift (genotype III to Genotype I). It is unclear if the newly dominant circulating G1-b genotype can still be vectored by Cx. quinquefasciatus. In this study, Cx. quinquefasciatus collected from North America was demonstrated to be competent for the transmission of the newly dominant genotype. Different infectivities observed between the endemic strains and non-endemic strain provides the mechanistic knowledge of the selection and emergence of endemic genotypes after continuous viral evolution.
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21
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Blitvich BJ, Wang T, Saxena V, Zeng S, Harmon KM, Raymond MD, Goins KM, Reed CR, Mullins RF, Greiner MA. West Nile Virus Infection in Human and Mouse Cornea Tissue. Am J Trop Med Hyg 2016; 95:1185-1191. [PMID: 27672204 DOI: 10.4269/ajtmh.16-0256] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2016] [Accepted: 08/01/2016] [Indexed: 12/13/2022] Open
Abstract
The purpose of this study was to determine the in vitro and ex vivo susceptibility of human corneal cells to West Nile virus (WNV) infection and evaluate the ability of the virus to disseminate to the corneas of infected mice. Human corneal epithelial cells were challenged with WNV, incubated for 1-6 days, and tested for evidence of WNV infection. Viral RNA and antigen were detected at every time point, and the virus reached a peak titer of 2.5 × 107 plaque-forming units (pfu)/mL at 3 days postinoculation (PI). Corneas procured from donors were incubated in culture dishes containing WNV for 1-5 days and tested for evidence of WNV. Viral RNA and antigen were detected, and the virus reached a mean peak titer of 4.9 × 104 pfu/mL at 5 days PI. Mice were inoculated intraperitoneally with WNV, and their eyes were harvested at 2, 5, and 8 days PI and tested for evidence of WNV. Viral RNA was detected in corneas of four of nine systemically infected mice as early as 2 days PI. We conclude that human corneal cells support WNV replication in vitro and ex vivo, and WNV may disseminate into the corneas of experimentally infected mice. These findings indicate that corneal transmission cannot be ruled out as a novel mode of human-to-human WNV transmission and additional experiments should be conducted to assess this risk further.
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Affiliation(s)
- Bradley J Blitvich
- Department of Veterinary Microbiology and Preventive Medicine, College of Veterinary Medicine, Iowa State University, Ames, Iowa
| | - Tian Wang
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas.,Department of Pathology, University of Texas Medical Branch, Galveston, Texas.,Sealy Center for Vaccine Development, University of Texas Medical Branch, Galveston, Texas
| | - Vandana Saxena
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas
| | - Shemin Zeng
- Department of Ophthalmology and Visual Sciences, Carver College of Medicine, University of Iowa, Iowa City, Iowa.,Stephen A. Wynn Institute for Vision Research, University of Iowa, Iowa City, Iowa
| | - Karen M Harmon
- Department of Veterinary Diagnostic and Production Animal Medicine, College of Veterinary Medicine, Iowa State University, Ames, Iowa
| | - Matthew D Raymond
- Department of Veterinary Diagnostic and Production Animal Medicine, College of Veterinary Medicine, Iowa State University, Ames, Iowa
| | - Kenneth M Goins
- Department of Ophthalmology and Visual Sciences, Carver College of Medicine, University of Iowa, Iowa City, Iowa.,Iowa Lions Eye Bank, Coralville, Iowa
| | | | - Robert F Mullins
- Department of Ophthalmology and Visual Sciences, Carver College of Medicine, University of Iowa, Iowa City, Iowa.,Stephen A. Wynn Institute for Vision Research, University of Iowa, Iowa City, Iowa
| | - Mark A Greiner
- Department of Ophthalmology and Visual Sciences, Carver College of Medicine, University of Iowa, Iowa City, Iowa. .,Stephen A. Wynn Institute for Vision Research, University of Iowa, Iowa City, Iowa.,Iowa Lions Eye Bank, Coralville, Iowa
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22
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Jia F, Zhu X, Xu F. A single adaptive point mutation in Japanese encephalitis virus capsid is sufficient to render the virus as a stable vector for gene delivery. Virology 2016; 490:109-18. [DOI: 10.1016/j.virol.2016.01.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2015] [Revised: 01/06/2016] [Accepted: 01/07/2016] [Indexed: 01/01/2023]
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23
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Szentpáli-Gavallér K, Lim SM, Dencső L, Bányai K, Koraka P, Osterhaus ADME, Martina BEE, Bakonyi T, Bálint Á. In Vitro and in Vivo Evaluation of Mutations in the NS Region of Lineage 2 West Nile Virus Associated with Neuroinvasiveness in a Mammalian Model. Viruses 2016; 8:v8020049. [PMID: 26907325 PMCID: PMC4776204 DOI: 10.3390/v8020049] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Revised: 01/19/2016] [Accepted: 02/09/2016] [Indexed: 12/25/2022] Open
Abstract
West Nile virus (WNV) strains may differ significantly in neuroinvasiveness in vertebrate hosts. In contrast to genetic lineage 1 WNVs, molecular determinants of pathogenic lineage 2 strains have not been experimentally confirmed so far. A full-length infectious clone of a neurovirulent WNV lineage 2 strain (578/10; Central Europe) was generated and amino acid substitutions that have been shown to attenuate lineage 1 WNVs were introduced into the nonstructural proteins (NS1 (P250L), NS2A (A30P), NS3 (P249H) NS4B (P38G, C102S, E249G)). The mouse neuroinvasive phenotype of each mutant virus was examined following intraperitoneal inoculation of C57BL/6 mice. Only the NS1-P250L mutation was associated with a significant attenuation of virulence in mice compared to the wild-type. Multiplication kinetics in cell culture revealed significantly lower infectious virus titres for the NS1 mutant compared to the wild-type, as well as significantly lower amounts of positive and negative stranded RNA.
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Affiliation(s)
| | - Stephanie M Lim
- Viroscience Laboratory, Erasmus Medical Centre, 3015CN, Rotterdam, The Netherlands.
| | - László Dencső
- Veterinary Diagnostic Directorate, National Food Chain Safety Office, H-1143, Budapest, Hungary.
| | - Krisztián Bányai
- Institute for Veterinary Medical Research, Centre for Agricultural Research, Hungarian Academy of Sciences, H-1143, Budapest, Hungary.
| | - Penelope Koraka
- Viroscience Laboratory, Erasmus Medical Centre, 3015CN, Rotterdam, The Netherlands.
| | | | - Byron E E Martina
- Viroscience Laboratory, Erasmus Medical Centre, 3015CN, Rotterdam, The Netherlands.
| | - Tamás Bakonyi
- Department of Microbiology and Infectious Diseases, Faculty of Veterinary Science, Szent István University, H-1143, Budapest, Hungary.
- Viral Zoonoses, Emerging and Vector-Borne Infections Group, Institute of Virology, University of Veterinary Medicine, A-1210, Vienna, Austria.
| | - Ádám Bálint
- Veterinary Diagnostic Directorate, National Food Chain Safety Office, H-1143, Budapest, Hungary.
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24
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Tsetsarkin KA, Liu G, Shen K, Pletnev AG. Kissing-loop interaction between 5' and 3' ends of tick-borne Langat virus genome 'bridges the gap' between mosquito- and tick-borne flaviviruses in mechanisms of viral RNA cyclization: applications for virus attenuation and vaccine development. Nucleic Acids Res 2016; 44:3330-50. [PMID: 26850640 PMCID: PMC4838367 DOI: 10.1093/nar/gkw061] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Accepted: 01/24/2016] [Indexed: 01/23/2023] Open
Abstract
Insertion of microRNA target sequences into the flavivirus genome results in selective tissue-specific attenuation and host-range restriction of live attenuated vaccine viruses. However, previous strategies for miRNA-targeting did not incorporate a mechanism to prevent target elimination under miRNA-mediated selective pressure, restricting their use in vaccine development. To overcome this limitation, we developed a new approach for miRNA-targeting of tick-borne flavivirus (Langat virus, LGTV) in the duplicated capsid gene region (DCGR). Genetic stability of viruses with DCGR was ensured by the presence of multiple cis-acting elements within the N-terminal capsid coding region, including the stem-loop structure (5′SL6) at the 3′ end of the promoter. We found that the 5′SL6 functions as a structural scaffold for the conserved hexanucleotide motif at its tip and engages in a complementary interaction with the region present in the 3′ NCR to enhance viral RNA replication. The resulting kissing-loop interaction, common in tick-borne flaviviruses, supports a single pair of cyclization elements (CYC) and functions as a homolog of the second pair of CYC that is present in the majority of mosquito-borne flaviviruses. Placing miRNA targets into the DCGR results in superior attenuation of LGTV in the CNS and does not interfere with development of protective immunity in immunized mice.
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Affiliation(s)
- Konstantin A Tsetsarkin
- Laboratory of Infectious Diseases, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Bethesda, MD, 20892-3203 USA
| | - Guangping Liu
- Laboratory of Infectious Diseases, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Bethesda, MD, 20892-3203 USA
| | - Kui Shen
- Bioinformatics and Computational Biosciences Branch, NIAID, NIH, Bethesda, MD, 20892, USA
| | - Alexander G Pletnev
- Laboratory of Infectious Diseases, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Bethesda, MD, 20892-3203 USA
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25
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Abstract
WNV infectious clones are valuable tools for elucidating WNV biology. Nevertheless, relatively few infectious WNV clones have been generated because their construction is hampered by the instability of flaviviral genomes. More recently, advances in cloning techniques as well as the development of several two-plasmid WNV infectious clone systems have facilitated the generation of WNV infectious clones. Here we described a protocol for recovering WNV from a two-plasmid system. In this approach, large quantities of these constructs are digested with restriction enzymes to produce complementary restriction sites at the 3' end of the upstream fragment and the 5' end of the downstream fragment. These fragments are then annealed to produce linear template for in vitro transcription to synthesize infectious RNA. The resulting RNA is transfected into cells and after several days WNV is recovered in the culture supernatant. This method can be used to generate virus from infectious clones encoding high- and low-pathogenicity strains of WNV, as well as chimeric virues.
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26
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Zhang PT, Shan C, Li XD, Liu SQ, Deng CL, Ye HQ, Shang BD, Shi PY, Lv M, Shen BF, Qin CF, Zhang B. Generation of a recombinant West Nile virus stably expressing the Gaussia luciferase for neutralization assay. Virus Res 2016; 211:17-24. [DOI: 10.1016/j.virusres.2015.09.015] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Revised: 09/22/2015] [Accepted: 09/23/2015] [Indexed: 10/23/2022]
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27
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Andreadis SS, Dimotsiou OC, Savopoulou-Soultani M. Variation in adult longevity of Culex pipiens f. pipiens, vector of the West Nile Virus. Parasitol Res 2014; 113:4315-9. [PMID: 25284257 DOI: 10.1007/s00436-014-4152-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2014] [Accepted: 09/23/2014] [Indexed: 10/24/2022]
Abstract
The common house mosquito, Culex pipiens (Diptera: Culicidae), which is considered the primary bridge vector of West Nile Virus (WNV) to humans, is a wide spread insect pest with medical importance and consists of two distinct bioforms, Cx. pipiens f. pipiens and Cx. pipiens f. molestus. Here, we consider the adult lifespan of male and female Cx. pipiens f. pipiens under controlled conditions at five constant temperature regimes (15, 20, 25, 27.5, and 30 °C). Our results show that adult longevity was affected by temperature, as it significantly decreased with increase in temperature. At the highest tested temperature, mean adult longevity did not exceed 12 days for both sexes and thus makes impossible the risk of WNV transmission. On the other hand at the lowest temperature, longevity was extremely high with some individuals surviving up to 129 and 132 days, males and females, respectively, and thus enable them to function as potential vectors of WNV for a prolonged period of time. As far as sex is concerned, adult females displayed a 1.2-1.4-fold longer longevity compared to the male ones. However, this difference was significant only at the lowest and highest tested temperature regime. This information is useful in determining the critical temperatures which may affect the distribution of Cx. pipiens and consequently the risk of WNV transmission. Moreover, the effect of environmental temperature should be considered when evaluating the abundance of these species.
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Affiliation(s)
- S S Andreadis
- Laboratory of Applied Zoology and Parasitology, Department of Plant Protection, Faculty of Agriculture, Aristotle University of Thessaloniki, 54124, Thessaloniki, Greece,
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28
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Mlera L, Melik W, Bloom ME. The role of viral persistence in flavivirus biology. Pathog Dis 2014; 71:137-63. [PMID: 24737600 PMCID: PMC4154581 DOI: 10.1111/2049-632x.12178] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2014] [Revised: 04/08/2014] [Accepted: 04/09/2014] [Indexed: 12/30/2022] Open
Abstract
In nature, vector borne flaviviruses are persistently cycled between either the tick or mosquito vector and small mammals such as rodents, skunks, and swine. These viruses account for considerable human morbidity and mortality worldwide. Increasing and substantial evidence of viral persistence in humans, which includes the isolation of RNA by RT PCR and infectious virus by culture, continues to be reported. Viral persistence can also be established in vitro in various human, animal, arachnid, and insect cell lines in culture. Although some research has focused on the potential roles of defective virus particles, evasion of the immune response through the manipulation of autophagy and/or apoptosis, the precise mechanism of flavivirus persistence is still not well understood. We propose additional research for further understanding of how viral persistence is established in different systems. Avenues for additional studies include determining whether the multifunctional flavivirus protein NS5 has a role in viral persistence, the development of relevant animal models of viral persistence, and investigating the host responses that allow vector borne flavivirus replication without detrimental effects on infected cells. Such studies might shed more light on the viral–host relationships and could be used to unravel the mechanisms for establishment of persistence. Persistent infections by vector borne flaviviruses are an important, but inadequately studied topic.
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Affiliation(s)
- Luwanika Mlera
- Rocky Mountain Laboratories, Laboratory of Virology, National Institutes of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, USA
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29
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Generation of West Nile virus infectious clones containing amino acid insertions between capsid and capsid anchor. Viruses 2014; 6:1637-53. [PMID: 24721788 PMCID: PMC4014714 DOI: 10.3390/v6041637] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2014] [Revised: 03/19/2014] [Accepted: 03/21/2014] [Indexed: 12/13/2022] Open
Abstract
West Nile virus (WNV) is a positive-sense RNA arbovirus responsible for recent outbreaks of severe neurological disease within the US and Europe. Large-scale analyses of antiviral compounds that inhibit virus replication have been limited due to the lack of an adequate WN reporter virus. Previous attempts to insert a reporter into the 3' untranslated region of WNV generated unstable viruses, suggesting that this region does not accommodate additional nucleotides. Here, we engineered two WNV infectious clones containing insertions at the Capsid (C)/Capsid Anchor (CA) junction of the viral polyprotein. Recombinant viruses containing a TAT(1-67) or Gaussia Luciferase (GLuc) gene at this location were successfully recovered. However, rapid loss of most, if not all, of the reporter sequence occurred for both viruses, indicating that the reporter viruses were not stable. While the GLuc viruses predominantly reverted back to wild-type WNV length, the TAT viruses retained up to 75 additional nucleotides of the reporter sequence. These additional nucleotides were stable over at least five passages and did not significantly alter WNV fitness. Thus, the C/CA junction of WNV can tolerate additional nucleotides, though insertions are subject to certain constraints.
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30
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In vivo bioluminescent imaging of influenza a virus infection and characterization of novel cross-protective monoclonal antibodies. J Virol 2013; 87:8272-81. [PMID: 23698304 DOI: 10.1128/jvi.00969-13] [Citation(s) in RCA: 121] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Influenza A virus is a major human pathogen responsible for seasonal epidemics as well as pandemic outbreaks. Due to the continuing burden on human health, the need for new tools to study influenza virus pathogenesis as well as to evaluate new therapeutics is paramount. We report the development of a stable, replication-competent luciferase reporter influenza A virus that can be used for in vivo imaging of viral replication. This imaging is noninvasive and allows for the longitudinal monitoring of infection in living animals. We used this tool to characterize novel monoclonal antibodies that bind the conserved stalk domain of the viral hemagglutinin of H1 and H5 subtypes and protect mice from lethal disease. The use of luciferase reporter influenza viruses allows for new mechanistic studies to expand our knowledge of virus-induced disease and provides a new quantitative method to evaluate future antiviral therapies.
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31
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Abstract
West Nile Virus was introduced into the Western Hemisphere during the late summer of 1999 and has been causing significant and sometimes severe human diseases since that time. This article briefly touches upon the biology of the virus and provides a comprehensive review regarding recent discoveries about virus transmission, virus acquisition, and human infection and disease.
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32
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Lazear HM, Lancaster A, Wilkins C, Suthar MS, Huang A, Vick SC, Clepper L, Thackray L, Brassil MM, Virgin HW, Nikolich-Zugich J, Moses AV, Gale M, Früh K, Diamond MS. IRF-3, IRF-5, and IRF-7 coordinately regulate the type I IFN response in myeloid dendritic cells downstream of MAVS signaling. PLoS Pathog 2013; 9:e1003118. [PMID: 23300459 PMCID: PMC3536698 DOI: 10.1371/journal.ppat.1003118] [Citation(s) in RCA: 231] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2012] [Accepted: 11/23/2012] [Indexed: 12/11/2022] Open
Abstract
Although the transcription factors IRF-3 and IRF-7 are considered master regulators of type I interferon (IFN) induction and IFN stimulated gene (ISG) expression, Irf3−/−×Irf7−/− double knockout (DKO) myeloid dendritic cells (mDC) produce relatively normal levels of IFN-β after viral infection. We generated Irf3−/−×Irf5−/−×Irf7−/− triple knockout (TKO) mice to test whether IRF-5 was the source of the residual induction of IFN-β and ISGs in mDCs. In pathogenesis studies with two unrelated positive-sense RNA viruses (West Nile virus (WNV) and murine norovirus), TKO mice succumbed at rates greater than DKO mice and equal to or approaching those of mice lacking the type I IFN receptor (Ifnar−/−). In ex vivo studies, after WNV infection or exposure to Toll-like receptor agonists, TKO mDCs failed to produce IFN-β or express ISGs. In contrast, this response was sustained in TKO macrophages following WNV infection. To define IRF-regulated gene signatures, we performed microarray analysis on WNV-infected mDC from wild type (WT), DKO, TKO, or Ifnar−/− mice, as well as from mice lacking the RIG-I like receptor adaptor protein MAVS. Whereas the gene induction pattern in DKO mDC was similar to WT cells, remarkably, almost no ISG induction was detected in TKO or Mavs−/− mDC. The relative equivalence of TKO and Mavs−/− responses suggested that MAVS dominantly regulates ISG induction in mDC. Moreover, we showed that MAVS-dependent induction of ISGs can occur through an IRF-5-dependent yet IRF-3 and IRF-7-independent pathway. Our results establish IRF-3, -5, and -7 as the key transcription factors responsible for mediating the type I IFN and ISG response in mDC during WNV infection and suggest a novel signaling link between MAVS and IRF-5. Host pathogen sensors, including those of the Toll-like receptor and RIG-I like receptor (RLR) families, detect viral infection in cells. Signaling through these receptors triggers expression of type I interferon (IFN) and IFN-stimulated genes (ISGs), in part through the IRF family of transcription factors. Previous studies with West Nile virus (WNV) showed that IRF-3 and IRF-7 control IFN expression in fibroblasts and neurons, whereas macrophages and myeloid dendritic cells (mDC) retained the ability to induce IFN-β without IRF-3 and IRF-7. In the current study, we generated Irf3−/−×Irf5−/−×Irf7−/− (TKO) mice to characterize the contributions of specific IRF transcription factors to IFN and ISG induction in response to WNV infection in cells and in mice. We found that induction of IFN and ISGs was largely abolished in TKO mDC, but sustained in TKO macrophages. Because IFN and ISG induction also was absent in mDC lacking MAVS, a key mediator of RLR signaling, our results suggest a novel signaling link between IRF-5 and MAVS. This study establishes the molecular pathways responsible for IFN induction in mDC and suggests a cross-talk between IRF-5 and RLR signaling pathways.
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Affiliation(s)
- Helen M. Lazear
- Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Alissa Lancaster
- Vaccine and Gene Therapy Institute, Oregon Health and Sciences University, Beaverton, Oregon, United States of America
| | - Courtney Wilkins
- University of Washington School of Medicine, Seattle, Washington, United States of America
| | - Mehul S. Suthar
- University of Washington School of Medicine, Seattle, Washington, United States of America
| | - Albert Huang
- University of Washington School of Medicine, Seattle, Washington, United States of America
| | - Sarah C. Vick
- Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Lisa Clepper
- Vaccine and Gene Therapy Institute, Oregon Health and Sciences University, Beaverton, Oregon, United States of America
| | - Larissa Thackray
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Margaret M. Brassil
- University of Washington School of Medicine, Seattle, Washington, United States of America
| | - Herbert W. Virgin
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Janko Nikolich-Zugich
- Department of Immunobiology and the Arizona Center on Aging, University of Arizona College of Medicine, Tucson, Arizona, United States of America
| | - Ashlee V. Moses
- Vaccine and Gene Therapy Institute, Oregon Health and Sciences University, Beaverton, Oregon, United States of America
| | - Michael Gale
- University of Washington School of Medicine, Seattle, Washington, United States of America
| | - Klaus Früh
- Vaccine and Gene Therapy Institute, Oregon Health and Sciences University, Beaverton, Oregon, United States of America
| | - Michael S. Diamond
- Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, United States of America
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri, United States of America
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, United States of America
- * E-mail:
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33
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Nuckols JT, Ziegler SA, Huang YJS, McAuley AJ, Vanlandingham DL, Klowden MJ, Spratt H, Davey RA, Higgs S. Infection of Aedes albopictus with chikungunya virus rectally administered by enema. Vector Borne Zoonotic Dis 2012; 13:103-10. [PMID: 23249139 DOI: 10.1089/vbz.2012.1013] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Chikungunya virus (CHIKV) is an alphavirus transmitted by Aedes albopictus and Aedes aegypti mosquitoes in tropical areas of Africa, Asia, and the islands of the Indian Ocean. In 2007 and 2009, CHIKV was transmitted outside these tropical areas and caused geographically localized infections in people in Italy and France. To temporally and spatially characterize CHIKV infection of Ae. albopictus midguts, a comparison of viral distribution in mosquitoes infected per os or by enema was conducted. Ae. albopictus infected with CHIKV LR 5' green fluorescent protein (GFP) at a titer 10(6.95) tissue culture infective dose(50) (TCID(50))/mL, were collected and analyzed for virus dissemination by visualizing GFP expression and titration up to 14 days post inoculation (dpi). Additionally, midguts were dissected from the mosquitoes and imaged by fluorescence microscopy for comparison of midgut infection patterns between orally- and enema-infected mosquitoes. When virus was delivered via enema, the anterior midgut appeared more readily infected by 3 dpi, with increased GFP presentation observed in this same location of the midgut at 7 and 14 dpi when compared to orally-infected mosquitoes. This work demonstrates that enema delivery of virus is a viable technique for use of mosquito infection. Enema injection of mosquitoes may be an alternative to intrathoracic inoculation because the enema delivery more closely models natural infection and neither compromises midgut integrity nor involves a wound that can induce immune responses. Furthermore, unlike intrathoracic delivery, the enema does not bypass midgut barriers to infect tissues artificially in the hemocoel of the mosquito.
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34
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Dengue reporter viruses reveal viral dynamics in interferon receptor-deficient mice and sensitivity to interferon effectors in vitro. Proc Natl Acad Sci U S A 2012; 109:14610-5. [PMID: 22908290 DOI: 10.1073/pnas.1212379109] [Citation(s) in RCA: 147] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Dengue virus (DENV) is a global disease threat for which there are no approved antivirals or vaccines. Establishing state-of-the-art screening systems that rely on fluorescent or luminescent reporters may accelerate the development of anti-DENV therapeutics. However, relatively few reporter DENV platforms exist. Here, we show that DENV can be genetically engineered to express a green fluorescent protein or firefly luciferase. Reporter viruses are infectious in vitro and in vivo and are sensitive to antiviral compounds, neutralizing antibodies, and interferons. Bioluminescence imaging was used to follow the dynamics of DENV infection in mice and revealed that the virus localized predominantly to lymphoid and gut-associated tissues. The high-throughput potential of reporter DENV was demonstrated by screening a library of more than 350 IFN-stimulated genes for antiviral activity. Several antiviral effectors were identified, and they targeted DENV at two distinct life cycle steps. These viruses provide a powerful platform for applications ranging from validation of vaccine candidates to antiviral discovery.
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35
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A novel approach for the rapid mutagenesis and directed evolution of the structural genes of west nile virus. J Virol 2012; 86:3501-12. [PMID: 22258236 DOI: 10.1128/jvi.06435-11] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Molecular clone technology has proven to be a powerful tool for investigating the life cycle of flaviviruses, their interactions with the host, and vaccine development. Despite the demonstrated utility of existing molecular clone strategies, the feasibility of employing these existing approaches in large-scale mutagenesis studies is limited by the technical challenges of manipulating relatively large molecular clone plasmids that can be quite unstable when propagated in bacteria. We have developed a novel strategy that provides an extremely rapid approach for the introduction of mutations into the structural genes of West Nile virus (WNV). The backbone of this technology is a truncated form of the genome into which DNA fragments harboring the structural genes are ligated and transfected directly into mammalian cells, bypassing entirely the requirement for cloning in bacteria. The transfection of cells with this system results in the rapid release of WNV that achieves a high titer (∼10(7) infectious units/ml in 48 h). The suitability of this approach for large-scale mutagenesis efforts was established in two ways. First, we constructed and characterized a library of variants encoding single defined amino acid substitutions at the 92 residues of the "pr" portion of the precursor-to-membrane (prM) protein. Analysis of a subset of these variants identified a mutation that conferred resistance to neutralization by an envelope protein-specific antibody. Second, we employed this approach to accelerate the identification of mutations that allow escape from neutralizing antibodies. Populations of WNV encoding random changes in the E protein were produced in the presence of a potent monoclonal antibody, E16. Viruses resistant to neutralization were identified in a single passage. Together, we have developed a simple and rapid approach to produce infectious WNV that accelerates the process of manipulating the genome to study the structure and function of the structural genes of this important human pathogen.
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36
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Leardkamolkarn V, Sirigulpanit W, Chotiwan N, Kumkate S, Huang CYH. Development of Dengue type-2 virus replicons expressing GFP reporter gene in study of viral RNA replication. Virus Res 2011; 163:552-62. [PMID: 22197424 DOI: 10.1016/j.virusres.2011.12.007] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2011] [Revised: 12/06/2011] [Accepted: 12/08/2011] [Indexed: 11/19/2022]
Abstract
Insertion of green fluorescent protein (GFP) encoding-gene into virus genes has provided a valuable tool for flavivirus research. This study aimed to develop dengue virus (DENV) replicons expressing GFP reporter that would provide a fast in vitro system to analyze functional roles of specific DENV sequences in viral replication. Two classes of recombinant replicon constructs were generated; one was a RNA-launched replicon with a GFP gene directly inserted into a full-length DENV genome (FL-DENV/GFP), and the other consisted of 4 types of DNA-launched DENV subgenomic replicons with GFP replacement at various structural genes (Δ-DENV/GFP). The FL-DENV/GFP resulted in GFP expression in transfected cells with no viable DENV being recovered from the transfection. The Δ-DENV/GFP constructs with partial structural gene deletion (ΔC-, ΔCprM/M-, ΔprM/M-, or ΔE-) expressed bright and long lasting GFP. The GFP expression intensity in living cells correlated well with the level of RNA replication. Various mutations in the 5'noncoding region of DENV-2 previously shown to be important genetic determinants for virus replication and mouse virulence were incorporated into the 5 different replicon constructs. Characterizations of 29 mutants demonstrated that these replicons can provide a useful platform for a quick and powerful in vitro system to analyze genetic determinants of DENV replication. These constructs can also be useful for development of vectors expressing foreign genes for various researches.
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McGee CE, Tsetsarkin KA, Guy B, Lang J, Plante K, Vanlandingham DL, Higgs S. Stability of yellow fever virus under recombinatory pressure as compared with chikungunya virus. PLoS One 2011; 6:e23247. [PMID: 21826243 PMCID: PMC3149644 DOI: 10.1371/journal.pone.0023247] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2011] [Accepted: 07/11/2011] [Indexed: 02/08/2023] Open
Abstract
Recombination is a mechanism whereby positive sense single stranded RNA viruses exchange segments of genetic information. Recent phylogenetic analyses of naturally occurring recombinant flaviviruses have raised concerns regarding the potential for the emergence of virulent recombinants either post-vaccination or following co-infection with two distinct wild-type viruses. To characterize the conditions and sequences that favor RNA arthropod-borne virus recombination we constructed yellow fever virus (YFV) 17D recombinant crosses containing complementary deletions in the envelope protein coding sequence. These constructs were designed to strongly favor recombination, and the detection conditions were optimized to achieve high sensitivity recovery of putative recombinants. Full length recombinant YFV 17D virus was never detected under any of the experimental conditions examined, despite achieving estimated YFV replicon co-infection levels of ∼2.4×106 in BHK-21 (vertebrate) cells and ∼1.05×105 in C710 (arthropod) cells. Additionally YFV 17D superinfection resistance was observed in vertebrate and arthropod cells harboring a primary infection with wild-type YFV Asibi strain. Furthermore recombination potential was also evaluated using similarly designed chikungunya virus (CHIKV) replicons towards validation of this strategy for recombination detection. Non-homologus recombination was observed for CHIKV within the structural gene coding sequence resulting in an in-frame duplication of capsid and E3 gene. Based on these data, it is concluded that even in the unlikely event of a high level acute co-infection of two distinct YFV genomes in an arthropod or vertebrate host, the generation of viable flavivirus recombinants is extremely unlikely.
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Affiliation(s)
- Charles E McGee
- Department of Pathology, University of Texas Medical Branch, Galveston, Texas, United States of America.
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Schoggins JW, Wilson SJ, Panis M, Murphy MY, Jones CT, Bieniasz P, Rice CM. A diverse range of gene products are effectors of the type I interferon antiviral response. Nature 2011; 472:481-5. [PMID: 21478870 PMCID: PMC3409588 DOI: 10.1038/nature09907] [Citation(s) in RCA: 1801] [Impact Index Per Article: 138.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2010] [Accepted: 02/03/2011] [Indexed: 12/12/2022]
Abstract
The type I interferon response protects cells against invading viral pathogens. The cellular factors that mediate this defence are the products of interferon-stimulated genes (ISGs). Although hundreds of ISGs have been identified since their discovery more than 25 years ago, only a few have been characterized with respect to antiviral activity. For most ISG products, little is known about their antiviral potential, their target specificity and their mechanisms of action. Using an overexpression screening approach, here we show that different viruses are targeted by unique sets of ISGs. We find that each viral species is susceptible to multiple antiviral genes, which together encompass a range of inhibitory activities. To conduct the screen, more than 380 human ISGs were tested for their ability to inhibit the replication of several important human and animal viruses, including hepatitis C virus, yellow fever virus, West Nile virus, chikungunya virus, Venezuelan equine encephalitis virus and human immunodeficiency virus type-1. Broadly acting effectors included IRF1, C6orf150 (also known as MB21D1), HPSE, RIG-I (also known as DDX58), MDA5 (also known as IFIH1) and IFITM3, whereas more targeted antiviral specificity was observed with DDX60, IFI44L, IFI6, IFITM2, MAP3K14, MOV10, NAMPT (also known as PBEF1), OASL, RTP4, TREX1 and UNC84B (also known as SUN2). Combined expression of pairs of ISGs showed additive antiviral effects similar to those of moderate type I interferon doses. Mechanistic studies uncovered a common theme of translational inhibition for numerous effectors. Several ISGs, including ADAR, FAM46C, LY6E and MCOLN2, enhanced the replication of certain viruses, highlighting another layer of complexity in the highly pleiotropic type I interferon system.
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Affiliation(s)
- John W Schoggins
- Laboratory of Virology and Infectious Disease, Center for the Study of Hepatitis C, The Rockefeller University, New York, New York 10065, USA
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