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Comes JDG, Doets K, Zegers T, Kessler M, Slits I, Ballesteros NA, van de Weem NMP, Pouwels H, van Oers MM, van Hulten MCW, Langereis M, Pijlman GP. Evaluation of bird-adapted self-amplifying mRNA vaccine formulations in chickens. Vaccine 2024; 42:2895-2908. [PMID: 38521674 DOI: 10.1016/j.vaccine.2024.03.032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Revised: 03/11/2024] [Accepted: 03/13/2024] [Indexed: 03/25/2024]
Abstract
Each year, millions of poultry succumb to highly pathogenic avian influenza A virus (AIV) and infectious bursal disease virus (IBDV) infections. Conventional vaccines based on inactivated or live-attenuated viruses are useful tools for disease prevention and control, yet, they often fall short in terms of safety, efficacy, and development times. Therefore, versatile vaccine platforms are crucial to protect poultry from emerging viral pathogens. Self-amplifying (replicon) RNA vaccines offer a well-defined and scalable option for the protection of both animals and humans. The best-studied replicon platform, based on the Venezuelan equine encephalitis virus (VEEV; family Togaviridae) TC-83 vaccine strain, however, displays limited efficacy in poultry, warranting the exploration of alternative, avian-adapted, replicon platforms. In this study, we engineered two Tembusu virus (TMUV; family Flaviviridae) replicons encoding varying capsid gene lengths and compared these to the benchmark VEEV replicon in vitro. The TMUV replicon system exhibited a robust and prolonged transgene expression compared to the VEEV replicon system in both avian and mammalian cells. Moreover, the TMUV replicon induced a lesser cytopathic effect compared to the VEEV replicon RNA in vitro. DNA-launched versions of the TMUV and VEEV replicons (DREP) were also developed. The replicons successfully expressed the AIV haemagglutinin (HA) glycoproteins and the IBDV capsid protein (pVP2). To assess the immune responses elicited by the TMUV replicon system in chickens, a prime-boost vaccination trial was conducted using lipid nanoparticle (LNP)-formulated replicon RNA and DREP encoding the viral (glyco)proteins of AIV or IBDV. Both TMUV and VEEV replicon RNAs were unable to induce a humoral response against AIV. However, TMUV replicon RNA induced IBDV-specific seroconversion in vaccinated chickens, in contrast to VEEV replicon RNA, which showed no significant humoral response. In both AIV and IBDV immunization studies, VEEV DREP generated the highest (neutralizing) antibody responses, which underscores the potential for self-amplifying mRNA vaccine technology to combat emerging poultry diseases.
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Affiliation(s)
- Jerome D G Comes
- Laboratory of Virology, Wageningen University & Research, Droevendaalsesteeg 1, Wageningen 6708PB, the Netherlands
| | - Kristel Doets
- Laboratory of Virology, Wageningen University & Research, Droevendaalsesteeg 1, Wageningen 6708PB, the Netherlands; MSD Animal Health, Wim de Körverstraat 35, Boxmeer 5831AN, the Netherlands
| | - Thijmen Zegers
- Laboratory of Virology, Wageningen University & Research, Droevendaalsesteeg 1, Wageningen 6708PB, the Netherlands
| | - Merel Kessler
- Laboratory of Virology, Wageningen University & Research, Droevendaalsesteeg 1, Wageningen 6708PB, the Netherlands
| | - Irene Slits
- Laboratory of Virology, Wageningen University & Research, Droevendaalsesteeg 1, Wageningen 6708PB, the Netherlands
| | | | | | - Henk Pouwels
- MSD Animal Health, Wim de Körverstraat 35, Boxmeer 5831AN, the Netherlands
| | - Monique M van Oers
- Laboratory of Virology, Wageningen University & Research, Droevendaalsesteeg 1, Wageningen 6708PB, the Netherlands
| | | | - Martijn Langereis
- MSD Animal Health, Wim de Körverstraat 35, Boxmeer 5831AN, the Netherlands
| | - Gorben P Pijlman
- Laboratory of Virology, Wageningen University & Research, Droevendaalsesteeg 1, Wageningen 6708PB, the Netherlands.
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2
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Chin WX, Kong HY, Zhu IXY, Teo ZY, Faruk R, Lee RCH, Ho SX, Aw ZQ, Yi B, Hou XJ, Tan AKY, Yogarajah T, Huber RG, Cai Y, Wan Y, Chu JJH. Flavivirus genome recoding by codon optimisation confers genetically stable in vivo attenuation in both mice and mosquitoes. PLoS Pathog 2023; 19:e1011753. [PMID: 37883598 PMCID: PMC10629665 DOI: 10.1371/journal.ppat.1011753] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Revised: 11/07/2023] [Accepted: 10/14/2023] [Indexed: 10/28/2023] Open
Abstract
Virus genome recoding is an attenuation method that confers genetically stable attenuation by rewriting a virus genome with numerous silent mutations. Prior flavivirus genome recoding attempts utilised codon deoptimisation approaches. However, these codon deoptimisation approaches act in a species dependent manner and were unable to confer flavivirus attenuation in mosquito cells or in mosquito animal models. To overcome these limitations, we performed flavivirus genome recoding using the contrary approach of codon optimisation. The genomes of flaviviruses such as dengue virus type 2 (DENV2) and Zika virus (ZIKV) contain functional RNA elements that regulate viral replication. We hypothesised that flavivirus genome recoding by codon optimisation would introduce silent mutations that disrupt these RNA elements, leading to decreased replication efficiency and attenuation. We chose DENV2 and ZIKV as representative flaviviruses and recoded them by codon optimising their genomes for human expression. Our study confirms that this recoding approach of codon optimisation does translate into reduced replication efficiency in mammalian, human, and mosquito cells as well as in vivo attenuation in both mice and mosquitoes. In silico modelling and RNA SHAPE analysis confirmed that DENV2 recoding resulted in the extensive disruption of genomic structural elements. Serial passaging of recoded DENV2 resulted in the emergence of rescue or adaptation mutations, but no reversion mutations. These rescue mutations were unable to rescue the delayed replication kinetics and in vivo attenuation of recoded DENV2, demonstrating that recoding confers genetically stable attenuation. Therefore, our recoding approach is a reliable attenuation method with potential applications for developing flavivirus vaccines.
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Affiliation(s)
- Wei-Xin Chin
- Laboratory of Molecular RNA Virology and Antiviral Strategies, Department of Microbiology and Immunology and Infectious Diseases Translational Research Programme, Yong Loo Lin School of Medicine, National University Health System, National University of Singapore, Singapore
| | - Hao Yuin Kong
- NUSMed Biosafety Level 3 Core Facility, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Isabelle Xin Yu Zhu
- Laboratory of Molecular RNA Virology and Antiviral Strategies, Department of Microbiology and Immunology and Infectious Diseases Translational Research Programme, Yong Loo Lin School of Medicine, National University Health System, National University of Singapore, Singapore
| | - Zi Yun Teo
- Laboratory of Molecular RNA Virology and Antiviral Strategies, Department of Microbiology and Immunology and Infectious Diseases Translational Research Programme, Yong Loo Lin School of Medicine, National University Health System, National University of Singapore, Singapore
| | - Regina Faruk
- Laboratory of Molecular RNA Virology and Antiviral Strategies, Department of Microbiology and Immunology and Infectious Diseases Translational Research Programme, Yong Loo Lin School of Medicine, National University Health System, National University of Singapore, Singapore
| | - Regina Ching Hua Lee
- Laboratory of Molecular RNA Virology and Antiviral Strategies, Department of Microbiology and Immunology and Infectious Diseases Translational Research Programme, Yong Loo Lin School of Medicine, National University Health System, National University of Singapore, Singapore
| | - Si Xian Ho
- Laboratory of Molecular RNA Virology and Antiviral Strategies, Department of Microbiology and Immunology and Infectious Diseases Translational Research Programme, Yong Loo Lin School of Medicine, National University Health System, National University of Singapore, Singapore
| | - Zhen Qin Aw
- NUSMed Biosafety Level 3 Core Facility, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Bowen Yi
- NUSMed Biosafety Level 3 Core Facility, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Xin Jun Hou
- Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore, Singapore
- Department of Biological Sciences, National University of Singapore, Singapore
| | - Antson Kiat Yee Tan
- Genome Institute of Singapore, Agency for Science, Technology and Research (A*STAR), Singapore
| | - Thinesshwary Yogarajah
- Laboratory of Molecular RNA Virology and Antiviral Strategies, Department of Microbiology and Immunology and Infectious Diseases Translational Research Programme, Yong Loo Lin School of Medicine, National University Health System, National University of Singapore, Singapore
| | - Roland G. Huber
- Bioinformatics Institute, Agency for Science, Technology and Research (A*STAR), Singapore
| | - Yu Cai
- Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore, Singapore
- Department of Biological Sciences, National University of Singapore, Singapore
| | - Yue Wan
- Genome Institute of Singapore, Agency for Science, Technology and Research (A*STAR), Singapore
| | - Justin Jang Hann Chu
- Laboratory of Molecular RNA Virology and Antiviral Strategies, Department of Microbiology and Immunology and Infectious Diseases Translational Research Programme, Yong Loo Lin School of Medicine, National University Health System, National University of Singapore, Singapore
- NUSMed Biosafety Level 3 Core Facility, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
- Institute of Molecular and Cell Biology, Agency for Science, Technology and Research (A*STAR), Singapore
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3
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Li D, Lu HT, Ding YZ, Wang HJ, Ye JL, Qin CF, Liu ZY. Specialized cis-Acting RNA Elements Balance Genome Cyclization to Ensure Efficient Replication of Yellow Fever Virus. J Virol 2023; 97:e0194922. [PMID: 37017533 PMCID: PMC10134800 DOI: 10.1128/jvi.01949-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Accepted: 03/13/2023] [Indexed: 04/06/2023] Open
Abstract
Genome cyclization is essential for viral RNA (vRNA) replication of the vertebrate-infecting flaviviruses, and yet its regulatory mechanisms are not fully understood. Yellow fever virus (YFV) is a notorious pathogenic flavivirus. Here, we demonstrated that a group of cis-acting RNA elements in YFV balance genome cyclization to govern efficient vRNA replication. It was shown that the downstream of the 5'-cyclization sequence hairpin (DCS-HP) is conserved in the YFV clade and is important for efficient YFV propagation. By using two different replicon systems, we found that the function of the DCS-HP is determined primarily by its secondary structure and, to a lesser extent, by its base-pair composition. By combining in vitro RNA binding and chemical probing assays, we found that the DCS-HP orchestrates the balance of genome cyclization through two different mechanisms, as follows: the DCS-HP assists the correct folding of the 5' end in a linear vRNA to promote genome cyclization, and it also limits the overstabilization of the circular form through a potential crowding effect, which is influenced by the size and shape of the DCS-HP structure. We also provided evidence that an A-rich sequence downstream of the DCS-HP enhances vRNA replication and contributes to the regulation of genome cyclization. Interestingly, diversified regulatory mechanisms of genome cyclization, involving both the downstream of the 5'-cyclization sequence (CS) and the upstream of the 3'-CS elements, were identified among different subgroups of the mosquito-borne flaviviruses. In summary, our work highlighted how YFV precisely controls the balance of genome cyclization to ensure viral replication. IMPORTANCE Yellow fever virus (YFV), the prototype of the Flavivirus genus, can cause devastating yellow fever disease. Although it is preventable by vaccination, there are still tens of thousands of yellow fever cases per year, and no approved antiviral medicine is available. However, the understandings about the regulatory mechanisms of YFV replication are obscure. In this study, by a combination of bioinformatics, reverse genetics, and biochemical approaches, it was shown that the downstream of the 5'-cyclization sequence hairpin (DCS-HP) promotes efficient YFV replication by modulating the conformational balance of viral RNA. Interestingly, we found specialized combinations for the downstream of the 5'-cyclization sequence (CS) and upstream of the 3'-CS elements in different groups of the mosquito-borne flaviviruses. Moreover, possible evolutionary relationships among the various downstream of the 5'-CS elements were implied. This work highlighted the complexity of RNA-based regulatory mechanisms in the flaviviruses and will facilitate the design of RNA structure-targeted antiviral therapies.
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Affiliation(s)
- Dan Li
- The Centre for Infection and Immunity Studies, School of Medicine, Sun Yat-sen University, Shenzhen, Guangdong, China
| | - Hai-Tao Lu
- The Centre for Infection and Immunity Studies, School of Medicine, Sun Yat-sen University, Shenzhen, Guangdong, China
| | - Yu-Zhen Ding
- The Centre for Infection and Immunity Studies, School of Medicine, Sun Yat-sen University, Shenzhen, Guangdong, China
| | - Hong-Jiang Wang
- Department of Virology, State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Academy of Military Medical Sciences, Beijing, China
- The Chinese People’s Liberation Army Strategic Support Force Characteristic Medical Center, Beijing, China
| | - Jing-Long Ye
- The Centre for Infection and Immunity Studies, School of Medicine, Sun Yat-sen University, Shenzhen, Guangdong, China
| | - Cheng-Feng Qin
- Department of Virology, State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Academy of Military Medical Sciences, Beijing, China
| | - Zhong-Yu Liu
- The Centre for Infection and Immunity Studies, School of Medicine, Sun Yat-sen University, Shenzhen, Guangdong, China
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Zu S, Li C, Li L, Deng YQ, Chen X, Luo D, Ye Q, Huang YJ, Li XF, Zhang RR, Sun N, Zhang X, Aliyari SR, Nielsen-Saines K, Jung JU, Yang H, Qin CF, Cheng G. TRIM22 suppresses Zika virus replication by targeting NS1 and NS3 for proteasomal degradation. Cell Biosci 2022; 12:139. [PMID: 36042495 PMCID: PMC9429444 DOI: 10.1186/s13578-022-00872-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Accepted: 08/03/2022] [Indexed: 12/03/2022] Open
Abstract
Background Recognition of viral invasion by innate antiviral immune system triggers activation of the type I interferon (IFN-I) and proinflammatory signaling pathways. Subsequently, IFN-I induction regulates expression of a group of genes known as IFN-I-stimulated genes (ISGs) to block viral infection. The tripartite motif containing 22 (TRIM22) is an ISG with strong antiviral functions. Results Here we have shown that the TRIM22 has been strongly upregulated both transcriptionally and translationally upon Zika virus (ZIKV) infection. ZIKV infection is associated with a wide range of clinical manifestations in human from mild to severe symptoms including abnormal fetal brain development. We found that the antiviral function of TRIM22 plays a crucial role in counterattacking ZIKV infection. Overexpression of TRIM22 protein inhibited ZIKV growth whereas deletion of TRIM22 in host cells increased ZIKV infectivity. Mechanistically, TRIM22, as a functional E3 ubiquitin ligase, promoted the ubiquitination and degradation of ZIKV nonstructural protein 1 (NS1) and nonstructural protein 3 (NS3). Further studies showed that the SPRY domain and Ring domain of TRIM22 played important roles in protein interaction and degradation, respectively. In addition, we found that TRIM22 also inhibited other flaviviruses infection including dengue virus (DENV) and yellow fever virus (YFV). Conclusion Thus, TRIM22 is an ISG with important role in host defense against flaviviruses through binding and degradation of the NS1 and NS3 proteins. Supplementary Information The online version contains supplementary material available at 10.1186/s13578-022-00872-w.
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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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Zeller MJ, Favorov O, Li K, Nuthanakanti A, Hussein D, Michaud A, Lafontaine DA, Busan S, Serganov A, Aubé J, Weeks KM. SHAPE-enabled fragment-based ligand discovery for RNA. Proc Natl Acad Sci U S A 2022; 119:e2122660119. [PMID: 35561226 PMCID: PMC9171761 DOI: 10.1073/pnas.2122660119] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Accepted: 04/05/2022] [Indexed: 11/30/2022] Open
Abstract
The transcriptome represents an attractive but underused set of targets for small-molecule ligands. Here, we devise a technology that leverages fragment-based screening and SHAPE-MaP RNA structure probing to discover small-molecule fragments that bind an RNA structure of interest. We identified fragments and cooperatively binding fragment pairs that bind to the thiamine pyrophosphate (TPP) riboswitch with millimolar to micromolar affinities. We then used structure-activity relationship information to efficiently design a linked-fragment ligand, with no resemblance to the native ligand, with high ligand efficiency and druglikeness, that binds to the TPP thiM riboswitch with high nanomolar affinity and that modulates RNA conformation during cotranscriptional folding. Principles from this work are broadly applicable, leveraging cooperativity and multisite binding, for developing high-quality ligands for diverse RNA targets.
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Affiliation(s)
- Meredith J. Zeller
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Oleg Favorov
- Department of Biomedical Engineering, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Kelin Li
- Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Ashok Nuthanakanti
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY 10016
| | - Dina Hussein
- Department of Biology, Faculty of Science, RNA Group, Université de Sherbrooke, Sherbrooke, J1K 2R1, QC, Canada
| | - Auréliane Michaud
- Department of Biology, Faculty of Science, RNA Group, Université de Sherbrooke, Sherbrooke, J1K 2R1, QC, Canada
| | - Daniel A. Lafontaine
- Department of Biology, Faculty of Science, RNA Group, Université de Sherbrooke, Sherbrooke, J1K 2R1, QC, Canada
| | - Steven Busan
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Alexander Serganov
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY 10016
| | - Jeffrey Aubé
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
- Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Kevin M. Weeks
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
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Yu Y, Gao C, Wen C, Zou P, Qi X, Cardona CJ, Xing Z. Intrinsic features of Zika Virus non-structural proteins NS2A and NS4A in the regulation of viral replication. PLoS Negl Trop Dis 2022; 16:e0010366. [PMID: 35522620 PMCID: PMC9075646 DOI: 10.1371/journal.pntd.0010366] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Accepted: 03/28/2022] [Indexed: 12/12/2022] Open
Abstract
Zika virus (ZIKV) is a mosquito-borne flavivirus and can cause neurodevelopmental disorders in fetus. As a neurotropic virus, ZIKV persistently infects neural tissues during pregnancy but the viral pathogenesis remains largely unknown. ZIKV has a positive-sense and single-stranded RNA genome, which encodes 7 non-structural (NS) proteins, participating in viral replication and dysregulation of host immunity. Like those in many other viruses, NS proteins are considered to be products evolutionarily beneficiary to viruses and some are virulence factors. However, we found that some NS proteins encoded by ZIKV genome appeared to function against the viral replication. In this report we showed that exogenously expressed ZIKV NS2A and NS4A inhibited ZIKV infection by inhibiting viral RNA replication in microglial cells and astrocytes. To understand how viral NS proteins suppressed viral replication, we analyzed the transcriptome of the microglial cells and astrocytes and found that expression of NS4A induced the upregulation of ISGs, including MX1/2, OAS1/2/3, IFITM1, IFIT1, IFI6, IFI27, ISG15 or BST2 through activating the ISGF3 signaling pathway. Upregulation of these ISGs seemed to be related to the inhibition of ZIKV replication, since the anti-ZIKV function of NS4A was partially attenuated when the cells were treated with Abrocitinib, an inhibitor of the ISGF3 signaling pathway, or were knocked down with STAT2. Aborting the protein expression of NS4A, but not its nucleic acid, eliminated the antiviral activity of NS4A effectively. Dynamic expression of viral NS proteins was examined in ZIKV-infected microglial cells and astrocytes, which showed comparatively NS4A occurred later than other NS proteins during the infection. We hypothesize that NS4A may possess intrinsic features to serve as a unique type of pathogen associated molecular pattern (PAMP), detectable by the cells to induce an innate immune response, or function with other mechanisms, to restrict the viral replication to a certain level as a negative feedback, which may help ZIKV maintain its persistent infection in fetal neural tissues. The birth of microcephaly infants due to ZIKV infection in pregnant women is related to ZIKV persistent infection. However, it is unclear how ZIKV maintains its persistent infection. In this work, we observed the delayed appearance of ZIKV NS4A protein in neuroglia including microglia and astrocytes compared with other non-structural proteins. Subsequently, we revealed that ZIKV NS4A inhibited viral RNA replication by activating the ISGF3 signaling pathway and inducing the production of ISGs. Aborting NS4A protein expression totally rescued ZIKV viral replication. Our study, combined with the previous findings, suggests that viral non-structural proteins may regulate viral replication, thus perpetuating ZIKV infection. Our hypothesis provides a mechanism for ZIKV to maintain its status of a persistent infection during viral infection in fetus, which can shed lights on our further understanding of viral neuropathogenesis in ZIKV infection.
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Affiliation(s)
- Yufeng Yu
- Shanxi Provincial Key Laboratory for Functional Proteins, School of Basic Medical Sciences, Shanxi Medical University, Taiyuan, Shanxi, China
- * E-mail: (YY); (ZX)
| | - Chengfeng Gao
- Jiangsu Key Laboratory of Molecular Medicine, Medical school, Nanjing University, Nanjing, Jiangsu, China
| | - Chunxia Wen
- Jiangsu Key Laboratory of Molecular Medicine, Medical school, Nanjing University, Nanjing, Jiangsu, China
| | - Peng Zou
- Shanghai Public Health Clinical Center, Fudan University, Shanghai, China
| | - Xian Qi
- Department of Acute Infectious Diseases Control and Prevention, Jiangsu Provincial Center for Disease Control and Prevention, Nanjing, Jiangsu, China
| | - Carol J. Cardona
- Department of Veterinary Biomedical Sciences, College of Veterinary Medicine, University of Minnesota at Twin Cities, Saint Paul, Minnesota, United States of America
| | - Zheng Xing
- Jiangsu Key Laboratory of Molecular Medicine, Medical school, Nanjing University, Nanjing, Jiangsu, China
- Department of Veterinary Biomedical Sciences, College of Veterinary Medicine, University of Minnesota at Twin Cities, Saint Paul, Minnesota, United States of America
- * E-mail: (YY); (ZX)
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8
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Morandi E, van Hemert MJ, Incarnato D. SHAPE-guided RNA structure homology search and motif discovery. Nat Commun 2022; 13:1722. [PMID: 35361788 PMCID: PMC8971488 DOI: 10.1038/s41467-022-29398-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Accepted: 03/11/2022] [Indexed: 01/13/2023] Open
Abstract
The rapidly growing popularity of RNA structure probing methods is leading to increasingly large amounts of available RNA structure information. This demands the development of efficient tools for the identification of RNAs sharing regions of structural similarity by direct comparison of their reactivity profiles, hence enabling the discovery of conserved structural features. We here introduce SHAPEwarp, a largely sequence-agnostic SHAPE-guided algorithm for the identification of structurally-similar regions in RNA molecules. Analysis of Dengue, Zika and coronavirus genomes recapitulates known regulatory RNA structures and identifies novel highly-conserved structural elements. This work represents a preliminary step towards the model-free search and identification of shared and conserved RNA structural features within transcriptomes.
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Affiliation(s)
- Edoardo Morandi
- Department of Molecular Genetics, Groningen Biomolecular Sciences and Biotechnology Institute (GBB), University of Groningen, Groningen, The Netherlands
| | - Martijn J van Hemert
- Department of Medical Microbiology, Molecular Virology Laboratory, Leiden University Medical Center, Leiden, The Netherlands
| | - Danny Incarnato
- Department of Molecular Genetics, Groningen Biomolecular Sciences and Biotechnology Institute (GBB), University of Groningen, Groningen, The Netherlands.
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Tracking the Replication-Competent Zika Virus with Tetracysteine-Tagged Capsid Protein in Living Cells. J Virol 2022; 96:e0184621. [PMID: 35285687 PMCID: PMC9006885 DOI: 10.1128/jvi.01846-21] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Zika virus (ZIKV) is the mosquito-borne enveloped flavivirus that causes microcephaly in neonates. While real-time imaging plays a critical role in dissecting viral biology, no fluorescent, genetically engineered ZIKV for single-particle tracking is currently available.
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10
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Yan ZY, Fang L, Xu XJ, Cheng DJ, Yu CM, Wang DY, Tian YP, Yuan XF, Geng C, Li XD. A Predicted Stem Loop in Coat Protein-Coding Sequence of Tobacco Vein Banding Mosaic Virus Is Required for Efficient Replication. PHYTOPATHOLOGY 2022; 112:441-451. [PMID: 34191551 DOI: 10.1094/phyto-10-20-0463-r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Potyviral coat protein (CP) is involved in the replication and movement of potyviruses. However, little information is available on the roles of CP-coding sequence in potyviral infection. Here, we introduced synonymous substitutions to the codon C574G575C576 coding conserved residue arginine at position 192 (R192) of tobacco vein banding mosaic virus (TVBMV) CP. Substitution of the codon C574G575C576 to A574G575A576 or A574G575G576, but not C574G575A576, C574G575T576, or C574G575G576, reduced the replication, cell-to-cell movement, and accumulation of TVBMV in Nicotiana benthamiana plants, suggesting that C574 was critical for replication of TVBMV. Nucleotides 531 to 576 of the TVBMV CP-coding sequence were predicted to form a stem-loop structure, in which four consecutive C-G base pairs (C576-G531, C532-G575, C574-G533, and C534-G573) were located at the stem. Synonymous substitutions of R178-codon C532G533C534 to A532G533A534 and A532G533G534, but not C532G533A534, C532G533T534, or C532G533G534, reduced the replication levels, cell-to-cell, and systemic movement of TVBMV, suggesting that C532 was critical for TVBMV replication. Synonymous substitutions disrupting base pairs C576-G531 and C534-G573 did not affect viral accumulation. After three serial-passage inoculations, the accumulation of spontaneous mutant viruses was restored, and codons A532G533A534, A532G533G534, A574G575A576, or A574G575G576 of mutants were each separately changed to C532G533A534, C532G533G534, C574G575A576, or C574G575G576. Synonymous mutation of R178 and R192 also reduced viral accumulation in N. tabacum plants. Therefore, we concluded that the two consecutive C532-G575 and C574-G533 base pairs played critical roles in TVBMV replication via maintaining the stability of the stem-loop structures formed by nucleotides 531 to 576 of the CP-coding sequence.
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Affiliation(s)
- Zhi-Yong Yan
- Laboratory of Plant Virology, College of Plant Protection, Shandong Agricultural University, Tai'an, Shandong 271018, P. R. China
| | - Le Fang
- Laboratory of Plant Virology, College of Plant Protection, Shandong Agricultural University, Tai'an, Shandong 271018, P. R. China
| | - Xiao-Jie Xu
- Laboratory of Plant Virology, College of Plant Protection, Shandong Agricultural University, Tai'an, Shandong 271018, P. R. China
| | - De-Jie Cheng
- Laboratory of Plant Virology, College of Plant Protection, Shandong Agricultural University, Tai'an, Shandong 271018, P. R. China
| | - Cheng-Ming Yu
- Shandong Provincial Key Laboratory of Agricultural Microbiology, Tai'an, Shandong 271018, P. R. China
| | - De-Ya Wang
- Shandong Provincial Key Laboratory of Agricultural Microbiology, Tai'an, Shandong 271018, P. R. China
| | - Yan-Ping Tian
- Laboratory of Plant Virology, College of Plant Protection, Shandong Agricultural University, Tai'an, Shandong 271018, P. R. China
- Shandong Provincial Key Laboratory of Agricultural Microbiology, Tai'an, Shandong 271018, P. R. China
| | - Xue-Feng Yuan
- Laboratory of Plant Virology, College of Plant Protection, Shandong Agricultural University, Tai'an, Shandong 271018, P. R. China
- Shandong Provincial Key Laboratory of Agricultural Microbiology, Tai'an, Shandong 271018, P. R. China
| | - Chao Geng
- Laboratory of Plant Virology, College of Plant Protection, Shandong Agricultural University, Tai'an, Shandong 271018, P. R. China
- Shandong Provincial Key Laboratory of Agricultural Microbiology, Tai'an, Shandong 271018, P. R. China
| | - Xiang-Dong Li
- Laboratory of Plant Virology, College of Plant Protection, Shandong Agricultural University, Tai'an, Shandong 271018, P. R. China
- Shandong Provincial Key Laboratory of Agricultural Microbiology, Tai'an, Shandong 271018, P. R. China
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11
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Novel reverse genetics of genotype I and III Japanese encephalitis viruses assembled through transformation associated recombination in yeast: The reporter viruses expressing a green fluorescent protein for the antiviral screening assay. Antiviral Res 2022; 197:105233. [DOI: 10.1016/j.antiviral.2021.105233] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Revised: 12/22/2021] [Accepted: 12/26/2021] [Indexed: 11/24/2022]
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12
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Li D, Ye JL, Liu ZY. Generation and Application of a Luciferase Reporter Virus Based on Yellow Fever Virus 17D. Virol Sin 2021; 36:1456-1464. [PMID: 34342842 DOI: 10.1007/s12250-021-00428-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Accepted: 06/08/2021] [Indexed: 11/29/2022] Open
Abstract
Yellow fever virus (YFV) is a re-emerging virus that can cause life-threatening yellow fever disease in humans. Despite the availability of an effective vaccine, little is known about the replication mechanism of YFV, and there are still no available specific anti-YFV medicines. Herein, by introducing the Renilla luciferase gene (Rluc) into an infectious clone of YFV vaccine strain 17D, we generated a recombinant virus 17D-Rluc.2A via reverse genetics approaches. The 17D-Rluc.2A had similar plaque morphology and comparable in vitro growth characteristics with its parental strain. Importantly, the reporter luciferase was efficiently expressed in 17D-Rluc.2A-infected mammalian and mosquito cells, and there was a good linear correlation between intracellular luciferase expression and extracellular infectious virion reproduction. Furthermore, by a combination of the 17D-Rluc.2A reporter virus and selective 2'-hydroxyl acylation analyzed by primer extension (SHAPE) technology, the conserved 5'-SLA element was shown to be essential for YFV replication, highlighting the capability of 17D-Rluc.2A in the investigation of YFV replication. At last, we demonstrated that two compounds with distinct anti-viral mechanisms can effectively inhibit the viral propagation in 17D-Rluc.2A-infected cells, demonstrating its potential application in the evaluation of anti-viral medicines. Taken together, the 17D-Rluc.2A serves as a useful tool for the study of YFV replication and anti-YFV medicine development.
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Affiliation(s)
- Dan Li
- The Centre for Infection and Immunity Studies, School of Medicine, Sun Yat-Sen University, Guangzhou, 510006, China
| | - Jing-Long Ye
- The Centre for Infection and Immunity Studies, School of Medicine, Sun Yat-Sen University, Guangzhou, 510006, China
| | - Zhong-Yu Liu
- The Centre for Infection and Immunity Studies, School of Medicine, Sun Yat-Sen University, Guangzhou, 510006, China.
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13
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Akiyama BM, Graham ME, O′Donoghue Z, Beckham J, Kieft J. Three-dimensional structure of a flavivirus dumbbell RNA reveals molecular details of an RNA regulator of replication. Nucleic Acids Res 2021; 49:7122-7138. [PMID: 34133732 PMCID: PMC8266583 DOI: 10.1093/nar/gkab462] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Revised: 05/07/2021] [Accepted: 05/17/2021] [Indexed: 11/14/2022] Open
Abstract
Mosquito-borne flaviviruses (MBFVs) including dengue, West Nile, yellow fever, and Zika viruses have an RNA genome encoding one open reading frame flanked by 5' and 3' untranslated regions (UTRs). The 3' UTRs of MBFVs contain regions of high sequence conservation in structured RNA elements known as dumbbells (DBs). DBs regulate translation and replication of the viral RNA genome, functions proposed to depend on the formation of an RNA pseudoknot. To understand how DB structure provides this function, we solved the x-ray crystal structure of the Donggang virus DB to 2.1Å resolution and used structural modeling to reveal the details of its three-dimensional fold. The structure confirmed the predicted pseudoknot and molecular modeling revealed how conserved sequences form a four-way junction that appears to stabilize the pseudoknot. Single-molecule FRET suggests that the DB pseudoknot is a stable element that can regulate the switch between translation and replication during the viral lifecycle by modulating long-range RNA conformational changes.
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Affiliation(s)
- Benjamin M Akiyama
- Department of Biochemistry and Molecular Genetics, Aurora, CO 80045, USA
| | - Monica E Graham
- Department of Immunology and Microbiology, Aurora, CO 80045, USA
| | - Zoe O′Donoghue
- Department of Immunology and Microbiology, Aurora, CO 80045, USA
| | - J David Beckham
- Department of Immunology and Microbiology, Aurora, CO 80045, USA
- Department of Medicine Division of Infectious Diseases, Aurora, CO 80045, USA
| | - Jeffrey S Kieft
- Department of Biochemistry and Molecular Genetics, Aurora, CO 80045, USA
- RNA BioScience Initiative, University of Colorado Denver School of Medicine, Aurora, CO 80045, USA
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14
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Zhang X, Zhang Y, Jia R, Wang M, Yin Z, Cheng A. Structure and function of capsid protein in flavivirus infection and its applications in the development of vaccines and therapeutics. Vet Res 2021; 52:98. [PMID: 34193256 PMCID: PMC8247181 DOI: 10.1186/s13567-021-00966-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Accepted: 05/27/2021] [Indexed: 01/03/2023] Open
Abstract
Flaviviruses are enveloped single positive-stranded RNA viruses. The capsid (C), a structural protein of flavivirus, is dimeric and alpha-helical, with several special structural and functional features. The functions of the C protein go far beyond a structural role in virions. It is not only responsible for encapsidation to protect the viral RNA but also able to interact with various host proteins to promote virus proliferation. Therefore, the C protein plays an important role in infected host cells and the viral life cycle. Flaviviruses have been shown to affect the health of humans and animals. Thus, there is an urgent need to effectively control flavivirus infections. The structure of the flavivirus virion has been determined, but there is relatively little information about the function of the C protein. Hence, a greater understanding of the role of the C protein in viral infections will help to discover novel antiviral strategies and provide a promising starting point for the further development of flavivirus vaccines or therapeutics.
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Affiliation(s)
- Xingcui Zhang
- Research Center of Avian Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, 611130, Sichuan, China.,Institute of Preventive Veterinary Medicine, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, 611130, Sichuan, China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, 611130, Sichuan, China
| | - Yanting Zhang
- Research Center of Avian Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, 611130, Sichuan, China.,Institute of Preventive Veterinary Medicine, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, 611130, Sichuan, China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, 611130, Sichuan, China
| | - Renyong Jia
- Research Center of Avian Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, 611130, Sichuan, China. .,Institute of Preventive Veterinary Medicine, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, 611130, Sichuan, China. .,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, 611130, Sichuan, China.
| | - Mingshu Wang
- Research Center of Avian Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, 611130, Sichuan, China.,Institute of Preventive Veterinary Medicine, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, 611130, Sichuan, China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, 611130, Sichuan, China
| | - Zhongqiong Yin
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, 611130, Sichuan, China
| | - Anchun Cheng
- Research Center of Avian Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, 611130, Sichuan, China. .,Institute of Preventive Veterinary Medicine, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, 611130, Sichuan, China. .,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, 611130, Sichuan, China.
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15
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Yong XE, Palur VR, Anand GS, Wohland T, Sharma KK. Dengue virus 2 capsid protein chaperones the strand displacement of 5'-3' cyclization sequences. Nucleic Acids Res 2021; 49:5832-5844. [PMID: 34037793 PMCID: PMC8191770 DOI: 10.1093/nar/gkab379] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 04/21/2021] [Accepted: 04/28/2021] [Indexed: 01/02/2023] Open
Abstract
By virtue of its chaperone activity, the capsid protein of dengue virus strain 2 (DENV2C) promotes nucleic acid structural rearrangements. However, the role of DENV2C during the interaction of RNA elements involved in stabilizing the 5′-3′ panhandle structure of DENV RNA is still unclear. Therefore, we determined how DENV2C affects structural functionality of the capsid-coding region hairpin element (cHP) during annealing and strand displacement of the 9-nt cyclization sequence (5CS) and its complementary 3CS. cHP has two distinct functions: a role in translation start codon selection and a role in RNA synthesis. Our results showed that cHP impedes annealing between 5CS and 3CS. Although DENV2C does not modulate structural functionality of cHP, it accelerates annealing and specifically promotes strand displacement of 3CS during 5′-3′ panhandle formation. Furthermore, DENV2C exerts its chaperone activity by favouring one of the active conformations of cHP. Based on our results, we propose mechanisms for annealing and strand displacement involving cHP. Thus, our results provide mechanistic insights into how DENV2C regulates RNA synthesis by modulating essential RNA elements in the capsid-coding region, that in turn allow for DENV replication.
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Affiliation(s)
- Xin Ee Yong
- NUS Graduate School Integrative Sciences and Engineering Programme, National University of Singapore, 21 Lower Kent Ridge Road, Singapore 119077, Singapore.,Centre for Bioimaging Sciences, National University of Singapore, 14 Science Drive 4, Singapore 117557, Singapore
| | - V Raghuvamsi Palur
- Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore 117543, Singapore
| | - Ganesh S Anand
- Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore 117543, Singapore
| | - Thorsten Wohland
- Centre for Bioimaging Sciences, National University of Singapore, 14 Science Drive 4, Singapore 117557, Singapore.,Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore 117543, Singapore
| | - Kamal K Sharma
- Centre for Bioimaging Sciences, National University of Singapore, 14 Science Drive 4, Singapore 117557, Singapore.,Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore 117543, Singapore
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16
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Ramos-Lorente S, Romero-López C, Berzal-Herranz A. Information Encoded by the Flavivirus Genomes beyond the Nucleotide Sequence. Int J Mol Sci 2021; 22:3738. [PMID: 33916729 PMCID: PMC8038387 DOI: 10.3390/ijms22073738] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 03/30/2021] [Accepted: 03/31/2021] [Indexed: 02/05/2023] Open
Abstract
The genus Flavivirus comprises numerous, small, single positive-stranded RNA viruses, many of which are important human pathogens. To store all the information required for their successful propagation, flaviviruses use discrete structural genomic RNA elements to code for functional information by the establishment of dynamic networks of long-range RNA-RNA interactions that promote specific folding. These structural elements behave as true cis-acting, non-coding RNAs (ncRNAs) and have essential regulatory roles in the viral cycle. These include the control of the formation of subgenomic RNAs, known as sfRNAs, via the prevention of the complete degradation of the RNA genome. These sfRNAs are important in ensuring viral fitness. This work summarizes our current knowledge of the functions performed by the genome conformations and the role of RNA-RNA interactions in these functions. It also reviews the role of RNA structure in the production of sfRNAs across the genus Flavivirus, and their existence in related viruses.
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Affiliation(s)
| | - Cristina Romero-López
- Instituto de Parasitología y Biomedicina López-Neyra (IPBLN-CSIC), Av. Conocimiento 17, Armilla, 18016 Granada, Spain;
| | - Alfredo Berzal-Herranz
- Instituto de Parasitología y Biomedicina López-Neyra (IPBLN-CSIC), Av. Conocimiento 17, Armilla, 18016 Granada, Spain;
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17
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Genetic Variation in the Domain II, 3' Untranslated Region of Human and Mosquito Derived Dengue Virus Strains in Sri Lanka. Viruses 2021; 13:v13030421. [PMID: 33807922 PMCID: PMC8001906 DOI: 10.3390/v13030421] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Revised: 02/25/2021] [Accepted: 02/26/2021] [Indexed: 02/07/2023] Open
Abstract
Genetic variations in dengue virus (DENV) play a distinct role in epidemic emergence. The DENV 3′ UTR has become a recent interest in research. The objective of the study was to examine the genetic variation in the domain II, 3′ UTR region of human and mosquito-derived DENV. DENV-infected human sera were orally infected to laboratory reared Aedes aegypti mosquitoes. The domain II, 3′ UTR of each human- and mosquito-derived sample was amplified. The nucleotide sequence variation, phylogenetic and secondary structure analysis was carried out incorporating respective regions of so far recorded Sri Lankan and the reference genotype strains of the DENV3 and DENV1 serotypes. The human- and mosquito-derived domain II, 3′ UTR were identical in nucleotide sequences within the serotypes isolated, indicating the conserved nature of the region during host switch. The sequence analysis revealed distinct variations in study isolates compared to so far recorded Sri Lankan isolates. However, despite single nucleotide variations, the maintenance of structural integrity was evident in related strains within the serotypes in the secondary structure analysis. The phylogenetic analysis revealed distinct clade segregation of the study sequences from so far reported Sri Lankan isolates and illustrated the phylogenetic relations of the study sequences to the available global isolates of respective serotypes.
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18
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Abstract
Recent studies have renewed interest in developing novel antiviral therapeutics and vaccines based on defective interfering particles (DIPs)—a subset of viral deletion mutants that conditionally replicate. Identifying and engineering DIPs require that viral cis- and trans-acting elements be accurately mapped. It has long been known that noncoding genomic regions can be obligate cis elements acted upon in trans by gene products. In viruses, cis elements regulate gene expression, encapsidation, and other maturation processes, but mapping these elements relies on targeted iterative deletion or laborious prospecting for rare spontaneously occurring mutants. Here, we introduce a method to comprehensively map viral cis and trans elements at single-nucleotide resolution by high-throughput random deletion. Variable-size deletions are randomly generated by transposon integration, excision, and exonuclease chewback and then barcoded for tracking via sequencing (i.e., random deletion library sequencing [RanDeL-seq]). Using RanDeL-seq, we generated and screened >23,000 HIV-1 variants to generate a single-base resolution map of HIV-1’s cis and trans elements. The resulting landscape recapitulated HIV-1’s known cis-acting elements (i.e., long terminal repeat [LTR], Ψ, and Rev response element [RRE]) and, surprisingly, indicated that HIV-1’s central DNA flap (i.e., central polypurine tract [cPPT] to central termination sequence [CTS]) is as critical as the LTR, Ψ, and RRE for long-term passage. Strikingly, RanDeL-seq identified a previously unreported ∼300-bp region downstream of RRE extending to splice acceptor 7 that is equally critical for sustained viral passage. RanDeL-seq was also used to construct and screen a library of >90,000 variants of Zika virus (ZIKV). Unexpectedly, RanDeL-seq indicated that ZIKV’s cis-acting regions are larger than the untranscribed (UTR) termini, encompassing a large fraction of the nonstructural genes. Collectively, RanDeL-seq provides a versatile framework for generating viral deletion mutants, enabling discovery of replication mechanisms and development of novel antiviral therapeutics, particularly for emerging viral infections.
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19
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Baker C, Liu Y, Zou J, Muruato A, Xie X, Shi PY. Identifying optimal capsid duplication length for the stability of reporter flaviviruses. Emerg Microbes Infect 2020; 9:2256-2265. [PMID: 32981479 PMCID: PMC7594839 DOI: 10.1080/22221751.2020.1829994] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 09/20/2020] [Accepted: 09/21/2020] [Indexed: 01/04/2023]
Abstract
ABSTRACT Mosquito-transmitted flaviviruses cause widespread disease across the world. To provide better molecular tools for drug screens and pathogenesis studies, we report a new approach to produce stable NanoLuc-tagged flaviviruses, including dengue virus serotypes 1-4, Japanese encephalitis virus, yellow fever virus, West Nile virus, and Zika virus. Since the reporter gene is often engineered at the capsid gene region, the capsid sequence must be duplicated to flank the reporter gene; such capsid duplication is essential for viral replication. The conventional approach for stabilizing reporter flaviviruses has been to shorten or modify the duplicated capsid sequence to minimize homologous recombination. No study has examined the effects of capsid duplication length on reporter virus stability. Here we report an optimal length to stabilize reporter flaviviruses. These viruses were stable after ten rounds of cell culture passaging, and in the case of stable NanoLuc-tagged Zika virus (ZIKV C38), the virus replicated to 107 FFU/ml in cell culture and produced robust luciferase signal after inoculation in mosquitoes. Mechanistically, the optimal length of capsid duplication may contain all the cis-acting RNA elements required for viral RNA replication, thus reducing the selection pressure for recombination. Together, these data describe an improved method of constructing optimal reporter flaviviruses.
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Affiliation(s)
- Coleman Baker
- Departement of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas, USA
| | - Yang Liu
- Department of Biology and Molecular Biology, University of Texas Medical Branch, Galveston, Texas, USA
| | - Jing Zou
- Department of Biology and Molecular Biology, University of Texas Medical Branch, Galveston, Texas, USA
| | - Antonio Muruato
- Departement of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas, USA
| | - Xuping Xie
- Department of Biology and Molecular Biology, University of Texas Medical Branch, Galveston, Texas, USA
| | - Pei-Yong Shi
- Department of Biology and Molecular Biology, University of Texas Medical Branch, Galveston, Texas, USA
- Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, TX, USA
- Sealy Center for Structural Biology and Molecular Biophysics, University of Texas Medical Branch, Galveston, TX, USA
- Sealy Institute for Vaccine Sciences, University of Texas Medical Branch, Galveston, TX, USA
- Sealy Institute for Translational Sciences, University of Texas Medical Branch, Galveston, TX, USA
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20
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He Y, Wang M, Chen S, Cheng A. The role of capsid in the flaviviral life cycle and perspectives for vaccine development. Vaccine 2020; 38:6872-6881. [PMID: 32950301 PMCID: PMC7495249 DOI: 10.1016/j.vaccine.2020.08.053] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Revised: 08/17/2020] [Accepted: 08/18/2020] [Indexed: 02/09/2023]
Abstract
The structure and function of flaviviral capsid are very flexible. The capsid gene contains conserved RNA secondary structures. Both steps of assembly and dissociation of nucleocapsid complexes are obscure. Capsid mutant viruses are highly attenuated and immunogenic. ΔC-replicon and single-round infectious particles are promising vaccine approaches.
The arthropod-borne flaviviruses cause a series of diseases in humans and pose a significant threat to global public health. In this review, we aimed to summarize the structure of the capsid protein (CP), its relevant multiple functions in the viral life cycle and innovative vaccines targeting CP. The flaviviral CP is the smallest structural protein and forms a homodimer by antiparallel α-helixes. Its primary function is to package the genomic RNA; however, both steps of assembly and dissociation of nucleocapsid complexes (NCs) have been obscure until now; in fact, flaviviral budding is NC-free, demonstrated by the subviral particles that generally exist in flavivirus infection. In infected cells, CPs associate with lipid droplets, which possibly store CPs prior to packaging. However, the function of nuclear localization of CPs remains unknown. Moreover, introducing deletions into CPs can be used to rationally design safe and effective live-attenuated vaccines or noninfectious replicon vaccines and single-round infectious particles, the latter two representing promising approaches for innovative flaviviral vaccine development.
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Affiliation(s)
- Yu He
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan 611130, China
| | - Mingshu Wang
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan 611130, China; Research Center of Avian Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan 611130, China; Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Chengdu, Sichuan 611130, China
| | - Shun Chen
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan 611130, China; Research Center of Avian Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan 611130, China; Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Chengdu, Sichuan 611130, China.
| | - Anchun Cheng
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan 611130, China; Research Center of Avian Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan 611130, China; Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Chengdu, Sichuan 611130, China.
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21
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Baker C, Xie X, Zou J, Muruato A, Fink K, Shi PY. Using recombination-dependent lethal mutations to stabilize reporter flaviviruses for rapid serodiagnosis and drug discovery. EBioMedicine 2020; 57:102838. [PMID: 32574959 PMCID: PMC7317239 DOI: 10.1016/j.ebiom.2020.102838] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2020] [Revised: 05/28/2020] [Accepted: 05/29/2020] [Indexed: 01/11/2023] Open
Abstract
Background Many flaviviruses are significant human pathogens that cause global public health threats. Developing research tools for studying and diagnosing these pathogens is a top priority. Reporter flaviviruses are useful tools for studying viral pathogenesis, diagnosing disease, and screening antiviral compounds. However, the stability of reporter flaviviruses has been challenged by viral RNA recombination, leading to deletion of the engineered reporter gene during viral replication. The instability of reporter viruses has limited their application to research and countermeasure development. Thus, new approaches to overcome the instability of reporter flaviviruses are critically needed to advance the flavivirus field. Methods To create a stable flavivirus bearing a reporter gene, we engineered mutations in the viral capsid gene that are rendered virus-lethal upon recombination. Thus, only non-recombined reporter virus propagates. We tested this strategy using Zika virus (ZIKV) bearing a nano-luciferase (NanoLuc) gene and passaged both virus with capsid mutations and virus without mutations. Findings The recombination-dependent lethal mutations succeeded in stabilizing the NanoLuc ZIKV through ten passages, while WT reporter virus showed instability as early as five passages. The stability of NanoLuc ZIKV was supported by RT-PCR, sequencing, focus forming assay, and luciferase assay. The success of this method was reconfirmed by also establishing a stable NanoLuc Yellow Fever 17D virus, indicating that the recombination-dependent lethal approach can be applied to other flaviviruses. To demonstrate the utility of the stable reporter viruses, we showed that NanoLuc ZIKV and YFV17D could be used to measure neutralizing antibody titers with a turnaround time as short as four hours. Importantly, the neutralizing antibody titers derived from the reporter virus assay were equivalent to those derived from the conventional plaque assay, indicating the new assay maintains the gold standard of serology testing. Furthermore, using a known inhibitor, we showed that the reporter viruses could be reliably used for antiviral evaluation. Interpretation The study has developed a recombination-dependent lethal approach to produce stable reporter flaviviruses that may be used for rapid serodiagnosis, trans-gene delivery, vaccine evaluation, and antiviral discovery. Funding National Institute of Health, Robert J. Kleberg, Jr. and Helen C. Kleberg Foundation; John S. Dunn Foundation; Amon G. Carter Foundation; Gillson Longenbaugh Foundation; Summerfield G. Roberts Foundation.
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Affiliation(s)
- Coleman Baker
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX, USA
| | - Xuping Xie
- Department of Biology and Molecular Biology, University of Texas Medical Branch, Galveston, TX, USA.
| | - Jing Zou
- Department of Biology and Molecular Biology, University of Texas Medical Branch, Galveston, TX, USA
| | - Antonio Muruato
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX, USA
| | - Katja Fink
- Singapore Immunology Network, Agency for Science, Technology and Research, Singapore
| | - Pei-Yong Shi
- Department of Biology and Molecular Biology, University of Texas Medical Branch, Galveston, TX, USA; Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, TX, USA; Sealy Center for Structural Biology and Molecular Biophysics, University of Texas Medical Branch, Galveston, TX, USA; Sealy Institute for Vaccine Sciences, University of Texas Medical Branch, Galveston, TX, USA.
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22
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Sanborn MA, Li T, Victor K, Siegfried H, Fung C, Rothman AL, Srikiatkhachorn A, Fernandez S, Ellison D, Jarman RG, Friberg H, Maljkovic Berry I, Currier JR, Waickman AT. Analysis of cell-associated DENV RNA by oligo(dT) primed 5' capture scRNAseq. Sci Rep 2020; 10:9047. [PMID: 32493997 PMCID: PMC7270085 DOI: 10.1038/s41598-020-65939-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Accepted: 05/12/2020] [Indexed: 01/12/2023] Open
Abstract
Dengue is one of the most widespread vector-borne viral diseases in the world. However, the size, heterogeneity, and temporal dynamics of the cell-associated viral reservoir during acute dengue virus (DENV) infection remains unclear. In this study, we analyzed cells infected in vitro with DENV and PBMC from an individual experiencing a natural DENV infection utilizing 5’ capture single cell RNA sequencing (scRNAseq). Both positive- and negative-sense DENV RNA was detected in reactions containing either an oligo(dT) primer alone, or in reactions supplemented with a DENV-specific primer. The addition of a DENV-specific primer did not increase the total amount of DENV RNA captured or the fraction of cells identified as containing DENV RNA. However, inclusion of a DENV-specific cDNA primer did increase the viral genome coverage immediately 5’ to the primer binding site. Furthermore, while the majority of intracellular DENV sequence captured in this analysis mapped to the 5’ end of the viral genome, distinct patterns of enhanced coverage within the DENV polyprotein coding region were observed. The 5’ capture scRNAseq analysis of PBMC not only recapitulated previously published reports by detecting virally infected memory and naïve B cells, but also identified cell-associated genomic variants not observed in contemporaneous serum samples. These results demonstrate that oligo(dT) primed 5’ capture scRNAseq can detect DENV RNA and quantify virus-infected cells in physiologically relevant conditions, and provides insight into viral sequence variability within infected cells.
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Affiliation(s)
- Mark A Sanborn
- Viral Diseases Branch, Walter Reed Army Institute of Research, Silver Spring, MD, USA
| | - Tao Li
- Viral Diseases Branch, Walter Reed Army Institute of Research, Silver Spring, MD, USA
| | - Kaitlin Victor
- Viral Diseases Branch, Walter Reed Army Institute of Research, Silver Spring, MD, USA
| | - Hayden Siegfried
- Viral Diseases Branch, Walter Reed Army Institute of Research, Silver Spring, MD, USA
| | - Christian Fung
- Viral Diseases Branch, Walter Reed Army Institute of Research, Silver Spring, MD, USA
| | - Alan L Rothman
- Department of Cell and Molecular Biology, Institute for Immunology and Informatics, University of Rhode Island, Providence, RI, USA
| | - Anon Srikiatkhachorn
- Department of Cell and Molecular Biology, Institute for Immunology and Informatics, University of Rhode Island, Providence, RI, USA.,Faculty of Medicine, King Mongkut's Institute of Technology Ladkrabang, Bangkok, Thailand
| | - Stefan Fernandez
- Department of Virology, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
| | - Damon Ellison
- Viral Diseases Branch, Walter Reed Army Institute of Research, Silver Spring, MD, USA
| | - Richard G Jarman
- Viral Diseases Branch, Walter Reed Army Institute of Research, Silver Spring, MD, USA
| | - Heather Friberg
- Viral Diseases Branch, Walter Reed Army Institute of Research, Silver Spring, MD, USA
| | - Irina Maljkovic Berry
- Viral Diseases Branch, Walter Reed Army Institute of Research, Silver Spring, MD, USA
| | - Jeffrey R Currier
- Viral Diseases Branch, Walter Reed Army Institute of Research, Silver Spring, MD, USA
| | - Adam T Waickman
- Viral Diseases Branch, Walter Reed Army Institute of Research, Silver Spring, MD, USA.
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23
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Fajardo T, Sanford TJ, Mears HV, Jasper A, Storrie S, Mansur DS, Sweeney TR. The flavivirus polymerase NS5 regulates translation of viral genomic RNA. Nucleic Acids Res 2020; 48:5081-5093. [PMID: 32313955 PMCID: PMC7229856 DOI: 10.1093/nar/gkaa242] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Revised: 03/30/2020] [Accepted: 04/01/2020] [Indexed: 11/14/2022] Open
Abstract
Flaviviruses, including dengue virus and Zika virus, contain a single-stranded positive sense RNA genome that encodes viral proteins essential for replication and also serves as the template for new genome synthesis. As these processes move in opposite directions along the genome, translation must be inhibited at a defined point following infection to clear the template of ribosomes to allow efficient replication. Here, we demonstrate in vitro and in cell-based assays that the viral RNA polymerase, NS5, inhibits translation of the viral genome. By reconstituting translation in vitro using highly purified components, we show that this translation block occurs at the initiation stage and that translation inhibition depends on NS5-RNA interaction, primarily through association with the 5' replication promoter region. This work supports a model whereby expression of a viral protein signals successful translation of the infecting genome, prompting a switch to a ribosome depleted replication-competent form.
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Affiliation(s)
- Teodoro Fajardo
- Division of Virology, Department of Pathology, University of Cambridge, Addenbrooke's Hospital, Hills Road, Cambridge, UK
| | - Thomas J Sanford
- Division of Virology, Department of Pathology, University of Cambridge, Addenbrooke's Hospital, Hills Road, Cambridge, UK
| | - Harriet V Mears
- Division of Virology, Department of Pathology, University of Cambridge, Addenbrooke's Hospital, Hills Road, Cambridge, UK
| | - Annika Jasper
- Division of Virology, Department of Pathology, University of Cambridge, Addenbrooke's Hospital, Hills Road, Cambridge, UK
| | - Skye Storrie
- Division of Virology, Department of Pathology, University of Cambridge, Addenbrooke's Hospital, Hills Road, Cambridge, UK
| | - Daniel S Mansur
- Laboratory of Immunobiology, Department of Microbiology, Immunology and Parasitology, Universidade Federal de Santa Catarina, Florianópolis, Brazil
| | - Trevor R Sweeney
- Division of Virology, Department of Pathology, University of Cambridge, Addenbrooke's Hospital, Hills Road, Cambridge, UK
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24
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Wang T, Li P, Zhang Y, Liu Y, Tan Z, Sun J, Ke X, Miao Y, Luo D, Hu Q, Xu F, Wang H, Zheng Z. In vivo imaging of Zika virus reveals dynamics of viral invasion in immune-sheltered tissues and vertical propagation during pregnancy. Am J Cancer Res 2020; 10:6430-6447. [PMID: 32483462 PMCID: PMC7255039 DOI: 10.7150/thno.43177] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Accepted: 05/01/2020] [Indexed: 12/11/2022] Open
Abstract
Rationale: Zika virus (ZIKV) is a pathogenic virus known to cause a wide range of congenital abnormalities, including microcephaly, Guillain-Barre syndrome, meningoencephalitis, and other neurological complications, in humans. This study investigated the noninvasive detection of ZIKV infection in vivo, which is necessary for elucidating the virus's mechanisms of viral replication and pathogenesis, as well as to accelerate the development of anti-ZIKV therapeutic strategies. Methods: In this study, a recombinant ZIKV harbouring Nluc gene (ZIKV-Nluc) was designed, recovered, and purified. The levels of bioluminescence were directly correlated with viral loads in vitro and in vivo. The dynamics of ZIKV infection in A129 (interferon (IFN)-α/β receptor deficient), AG6 (IFN-α/β and IFN-γ receptor deficient), and C57BL/6 mice were characterized. Pregnant dams were infected with ZIKV-Nluc at E10 via intra footpad injection. Then, the pooled immune sera (anti-ZIKV neutralizing antibodies) #22-1 in ZIKV-Nluc virus-infected mice were visualized. Results: ZIKV-Nluc showed a high genetic stability and replicated well in cells with similar properties to the wild-type ZIKV (ZIKVwt). Striking bioluminescence signals were consistently observed in animal organs, including spleen, intestine, testis, uterus/ovary, and kidney. The ileocecal junction was found to be the crucial visceral target. Infection of pregnant dams with ZIKV-Nluc showed that ZIKV was capable of crossing the maternal-fetal barrier to infect the fetuses via vertical transmission. Furthermore, it was visualized that treatment with the pooled immune sera was found to greatly restrict the spread of the ZIKV-Nluc virus in mice. Conclusions: This study is the first to report the real-time noninvasive tracking of the progression of ZIKV invading immune-sheltered tissues and propagating vertically during pregnancy. The results demonstrate that ZIKV-Nluc represents a powerful tool for the study of the replication, dissemination, pathogenesis, and treatment of ZIKV in vitro and in vivo.
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25
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Different Degrees of 5'-to-3' DAR Interactions Modulate Zika Virus Genome Cyclization and Host-Specific Replication. J Virol 2020; 94:JVI.01602-19. [PMID: 31826997 PMCID: PMC7022364 DOI: 10.1128/jvi.01602-19] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Accepted: 12/06/2019] [Indexed: 01/06/2023] Open
Abstract
Mosquito-borne flaviviruses, which include many important human pathogens, such as West Nile virus (WNV), dengue virus (DENV), and Zika virus (ZIKV), have caused numerous emerging epidemics in recent years. Details of the viral genome functions necessary for effective viral replication in mosquito and vertebrate hosts remain obscure. Here, using ZIKV as a model, we found that the conserved "downstream of AUG region" (DAR), which is known to be an essential element for genome cyclization, is involved in viral replication in a host-specific manner. Mutational analysis of the DAR element showed that a single-nucleotide mismatch between the 5' DAR and the 3' DAR had little effect on ZIKV replication in mammalian cells but dramatically impaired viral propagation in mosquito cells. The revertant viruses passaged in mosquito cells generated compensatory mutations restoring the base pairing of the DAR, further confirming the importance of the complementarity of the DAR in mosquito cells. We demonstrate that a single-nucleotide mutation in the DAR is sufficient to destroy long-range RNA interaction of the ZIKV genome and affects de novo RNA synthesis at 28°C instead of 37°C, resulting in the different replication efficiencies of the mutant viruses in mosquito and mammalian cells. Our results reveal a novel function of the circular form of the flavivirus genome in host-specific viral replication, providing new ideas to further explore the functions of the viral genome during host adaptation.IMPORTANCE Flaviviruses naturally cycle between the mosquito vector and vertebrate hosts. The disparate hosts provide selective pressures that drive virus genome evolution to maintain efficient replication during host alteration. Host adaptation may occur at different stages of the viral life cycle, since host-specific viral protein processing and virion conformations have been reported in the individual hosts. However, the viral determinants and the underlying mechanisms associated with host-specific functions remain obscure. In this study, using Zika virus, we found that the DAR-mediated genome cyclization regulates viral replication differently and is under different selection pressures in mammalian and mosquito cells. A more constrained complementarity of the DAR is required in mosquito cells than in mammalian cells. Since the DAR element is stably maintained among mosquito-borne flaviviruses, our findings could provide new information for understanding the role of flavivirus genome cyclization in viral adaptation and RNA evolution in the two hosts.
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26
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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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27
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Liu ZY, Qin CF. Structure and function of cis-acting RNA elements of flavivirus. Rev Med Virol 2019; 30:e2092. [PMID: 31777997 DOI: 10.1002/rmv.2092] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Revised: 10/12/2019] [Accepted: 10/20/2019] [Indexed: 12/23/2022]
Abstract
The genus Flavivirus is a group of single-stranded, positive-sense RNA viruses that includes numerous human pathogens with global impact, such as dengue virus (DENV), yellow fever virus (YFV), West Nile virus (WNV), and Zika virus (ZIKV). The approximately 11-kilobase genome is flanked by highly structured untranslated regions (UTRs), which contain various cis-acting RNA elements with unique structures and functions. Moreover, local RNA elements circularize the genome non-covalently through long-range interactions. Interestingly, many flavivirus cis-acting RNA elements contain group-specific motifs or are specific for the given phylogenetic groups, suggesting their potential association with flavivirus evolution and diversification. In this review, we summarize recent advances about the structure and function of cis-acting RNA elements in flavivirus genomes and highlight the potential implications for flavivirus evolution. Finally, the scientific questions remained to be answered in the field are also discussed.
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Affiliation(s)
- Zhong-Yu Liu
- Department of Virology, State Key Laboratory of Pathogen and Biosecurity, Institute of Microbiology and Epidemiology, Academy of Military Medical Sciences, Beijing, China.,School of Medicine Shenzhen, Sun Yat-sen University, Guangzhou, China.,The No. 8 People's Hospital, Guangzhou Medical University, Guangzhou, China
| | - Cheng-Feng Qin
- Department of Virology, State Key Laboratory of Pathogen and Biosecurity, Institute of Microbiology and Epidemiology, Academy of Military Medical Sciences, Beijing, China.,The No. 8 People's Hospital, Guangzhou Medical University, Guangzhou, China
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28
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Abstract
RNA viruses encode the information required to usurp cellular metabolism and gene regulation and to enable their own replication in two ways: in the linear sequence of their RNA genomes and in higher-order structures that form when the genomic RNA strand folds back on itself. Application of high-resolution SHAPE (selective 2'-hydroxyl acylation analyzed by primer extension) structure probing to viral RNA genomes has identified numerous new regulatory elements, defined new principles by which viral RNAs interact with the cellular host and evade host immune responses, and revealed relationships between virus evolution and RNA structure. This review summarizes our current understanding of genome structure-function interrelationships for RNA viruses, as informed by SHAPE structure probing, and outlines opportunities for future studies.
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Affiliation(s)
- Mark A Boerneke
- Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599-3290, USA; , ,
| | - Jeffrey E Ehrhardt
- Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599-3290, USA; , ,
| | - Kevin M Weeks
- Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599-3290, USA; , ,
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29
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Abstract
Understanding RNA-mediated functions requires a detailed characterization of the underlying RNA structure. In many cases, structure probing experiments are performed on RNA that has been "refolded" in some way, which may cause the conformation to differ from that of the native RNA. We used SHAPE-MaP (selective 2'-hydroxyl acylation analyzed by primer extension, read out by mutational profiling), to probe the structure of the Dengue virus (DENV) RNA genome after gentle extraction of the native RNA from intact virions (ex virion) and after heat denaturation and refolding. Comparison of mutiple SHAPE-informed structural features revealed that refolded RNA is more highly structured and samples fewer conformations than the ex virion RNA. Regions with similar structural features are generally those with low SHAPE reactivity and low Shannon entropy (lowSS regions), which correspond to elements with high levels of well-determined structure. This high-structure and low-entropy analysis framework, previously shown to make possible discovery of functional RNA structures, is thus now shown to allow de novo identification of structural elements in a refolded RNA that are likely to recapitulate RNA structures in the ex virion RNA state. Regions with less well-defined structures, which occurred more frequently in the more native-like ex virion RNA and may contain RNA switches, are challenging to recapitulate using refolded RNA.
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Affiliation(s)
- Elizabeth A Dethoff
- Department of Chemistry , The University of North Carolina , Chapel Hill , North Carolina 27599-3290 , United States
| | - Kevin M Weeks
- Department of Chemistry , The University of North Carolina , Chapel Hill , North Carolina 27599-3290 , United States
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30
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Abstract
Flaviviruses include a diverse group of medically important viruses that cycle between mosquitoes and humans. During this natural process of switching hosts, each species imposes different selective forces on the viral population. Using dengue virus (DENV) as model, we found that paralogous RNA structures originating from duplications in the viral 3' untranslated region (UTR) are under different selective pressures in the two hosts. These RNA structures, known as dumbbells (DB1 and DB2), were originally proposed to be enhancers of viral replication. Analysis of viruses obtained from infected mosquitoes showed selection of mutations that mapped in DB2. Recombinant viruses carrying the identified variations confirmed that these mutations greatly increase viral replication in mosquito cells, with low or no impact in human cells. Use of viruses lacking each of the DB structures revealed opposite viral phenotypes. While deletion of DB1 reduced viral replication about 10-fold, viruses lacking DB2 displayed a great increase of fitness in mosquitoes, confirming a functional diversification of these similar RNA elements. Mechanistic analysis indicated that DB1 and DB2 differentially modulate viral genome cyclization and RNA replication. We found that a pseudoknot formed within DB2 competes with long-range RNA-RNA interactions that are necessary for minus-strand RNA synthesis. Our results support a model in which a functional diversification of duplicated RNA elements in the viral 3' UTR is driven by host-specific requirements. This study provides new ideas for understanding molecular aspects of the evolution of RNA viruses that naturally jump between different species.IMPORTANCE Flaviviruses constitute the most relevant group of arthropod-transmitted viruses, including important human pathogens such as the dengue, Zika, yellow fever, and West Nile viruses. The natural alternation of these viruses between vertebrate and invertebrate hosts shapes the viral genome population, which leads to selection of different viral variants with potential implications for epidemiological fitness and pathogenesis. However, the selective forces and mechanisms acting on the viral RNA during host adaptation are still largely unknown. Here, we found that two almost identical tandem RNA structures present at the viral 3' untranslated region are under different selective pressures in the two hosts. Mechanistic studies indicated that the two RNA elements, known as dumbbells, contain sequences that overlap essential RNA cyclization elements involved in viral RNA synthesis. The data support a model in which the duplicated RNA structures differentially evolved to accommodate distinct functions for viral replication in the two hosts.
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31
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Mazeaud C, Freppel W, Chatel-Chaix L. The Multiples Fates of the Flavivirus RNA Genome During Pathogenesis. Front Genet 2018. [PMID: 30564270 DOI: 10.3389/fgene.2018.00595/full] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/26/2023] Open
Abstract
The Flavivirus genus comprises many viruses (including dengue, Zika, West Nile and yellow fever viruses) which constitute important public health concerns worldwide. For several of these pathogens, neither antivirals nor vaccines are currently available. In addition to this unmet medical need, flaviviruses are of particular interest since they constitute an excellent model for the study of spatiotemporal regulation of RNA metabolism. Indeed, with no DNA intermediate or nuclear step, the flaviviral life cycle entirely relies on the cytoplasmic fate of a single RNA species, namely the genomic viral RNA (vRNA) which contains all the genetic information necessary for optimal viral replication. From a single open reading frame, the vRNA encodes a polyprotein which is processed to generate the mature viral proteins. In addition to coding for the viral polyprotein, the vRNA serves as a template for RNA synthesis and is also selectively packaged into newly assembled viral particles. Notably, vRNA translation, replication and encapsidation must be tightly coordinated in time and space via a fine-tuned equilibrium as these processes cannot occur simultaneously and hence, are mutually exclusive. As such, these dynamic processes involve several vRNA secondary and tertiary structures as well as RNA modifications. Finally, the vRNA can be detected as a foreign molecule by cytosolic sensors which trigger upon activation antiviral signaling pathways and the production of antiviral factors such as interferons and interferon-stimulated genes. However, to create an environment favorable to infection, flaviviruses have evolved mechanisms to dampen these antiviral processes, notably through the production of a specific vRNA degradation product termed subgenomic flavivirus RNA (sfRNA). In this review, we discuss the current understanding of the fates of flavivirus vRNA and how this is regulated at the molecular level to achieve an optimal replication within infected cells.
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Affiliation(s)
- Clément Mazeaud
- Institut National de la Recherche Scientifique, Centre INRS-Institut Armand-Frappier, Laval, QC, Canada
| | - Wesley Freppel
- Institut National de la Recherche Scientifique, Centre INRS-Institut Armand-Frappier, Laval, QC, Canada
| | - Laurent Chatel-Chaix
- Institut National de la Recherche Scientifique, Centre INRS-Institut Armand-Frappier, Laval, QC, Canada
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32
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Andrews RJ, Roche J, Moss WN. ScanFold: an approach for genome-wide discovery of local RNA structural elements-applications to Zika virus and HIV. PeerJ 2018; 6:e6136. [PMID: 30627482 PMCID: PMC6317755 DOI: 10.7717/peerj.6136] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Accepted: 11/15/2018] [Indexed: 12/24/2022] Open
Abstract
In addition to encoding RNA primary structures, genomes also encode RNA secondary and tertiary structures that play roles in gene regulation and, in the case of RNA viruses, genome replication. Methods for the identification of functional RNA structures in genomes typically rely on scanning analysis windows, where multiple partially-overlapping windows are used to predict RNA structures and folding metrics to deduce regions likely to form functional structure. Separate structural models are produced for each window, where the step size can greatly affect the returned model. This makes deducing unique local structures challenging, as the same nucleotides in each window can be alternatively base paired. We are presenting here a new approach where all base pairs from analysis windows are considered and weighted by favorable folding. This results in unique base pairing throughout the genome and the generation of local regions/structures that can be ranked by their propensity to form unusually thermodynamically stable folds. We applied this approach to the Zika virus (ZIKV) and HIV-1 genomes. ZIKV is linked to a variety of neurological ailments including microcephaly and Guillain-Barré syndrome and its (+)-sense RNA genome encodes two, previously described, functionally essential structured RNA regions. HIV, the cause of AIDS, contains multiple functional RNA motifs in its genome, which have been extensively studied. Our approach is able to successfully identify and model the structures of known functional motifs in both viruses, while also finding additional regions likely to form functional structures. All data have been archived at the RNAStructuromeDB (www.structurome.bb.iastate.edu), a repository of RNA folding data for humans and their pathogens.
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Affiliation(s)
- Ryan J. Andrews
- Roy J. Carver Department of Biophysics, Biochemistry and Molecular Biology, Iowa State University, Ames, IA, USA
| | - Julien Roche
- Roy J. Carver Department of Biophysics, Biochemistry and Molecular Biology, Iowa State University, Ames, IA, USA
| | - Walter N. Moss
- Roy J. Carver Department of Biophysics, Biochemistry and Molecular Biology, Iowa State University, Ames, IA, USA
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33
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Mazeaud C, Freppel W, Chatel-Chaix L. The Multiples Fates of the Flavivirus RNA Genome During Pathogenesis. Front Genet 2018; 9:595. [PMID: 30564270 PMCID: PMC6288177 DOI: 10.3389/fgene.2018.00595] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Accepted: 11/15/2018] [Indexed: 12/11/2022] Open
Abstract
The Flavivirus genus comprises many viruses (including dengue, Zika, West Nile and yellow fever viruses) which constitute important public health concerns worldwide. For several of these pathogens, neither antivirals nor vaccines are currently available. In addition to this unmet medical need, flaviviruses are of particular interest since they constitute an excellent model for the study of spatiotemporal regulation of RNA metabolism. Indeed, with no DNA intermediate or nuclear step, the flaviviral life cycle entirely relies on the cytoplasmic fate of a single RNA species, namely the genomic viral RNA (vRNA) which contains all the genetic information necessary for optimal viral replication. From a single open reading frame, the vRNA encodes a polyprotein which is processed to generate the mature viral proteins. In addition to coding for the viral polyprotein, the vRNA serves as a template for RNA synthesis and is also selectively packaged into newly assembled viral particles. Notably, vRNA translation, replication and encapsidation must be tightly coordinated in time and space via a fine-tuned equilibrium as these processes cannot occur simultaneously and hence, are mutually exclusive. As such, these dynamic processes involve several vRNA secondary and tertiary structures as well as RNA modifications. Finally, the vRNA can be detected as a foreign molecule by cytosolic sensors which trigger upon activation antiviral signaling pathways and the production of antiviral factors such as interferons and interferon-stimulated genes. However, to create an environment favorable to infection, flaviviruses have evolved mechanisms to dampen these antiviral processes, notably through the production of a specific vRNA degradation product termed subgenomic flavivirus RNA (sfRNA). In this review, we discuss the current understanding of the fates of flavivirus vRNA and how this is regulated at the molecular level to achieve an optimal replication within infected cells.
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Affiliation(s)
- Clément Mazeaud
- Institut National de la Recherche Scientifique, Centre INRS-Institut Armand-Frappier, Laval, QC, Canada
| | - Wesley Freppel
- Institut National de la Recherche Scientifique, Centre INRS-Institut Armand-Frappier, Laval, QC, Canada
| | - Laurent Chatel-Chaix
- Institut National de la Recherche Scientifique, Centre INRS-Institut Armand-Frappier, Laval, QC, Canada
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Li P, Wei Y, Mei M, Tang L, Sun L, Huang W, Zhou J, Zou C, Zhang S, Qin CF, Jiang T, Dai J, Tan X, Zhang QC. Integrative Analysis of Zika Virus Genome RNA Structure Reveals Critical Determinants of Viral Infectivity. Cell Host Microbe 2018; 24:875-886.e5. [PMID: 30472207 DOI: 10.1016/j.chom.2018.10.011] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Revised: 09/21/2018] [Accepted: 10/24/2018] [Indexed: 01/25/2023]
Abstract
Zika virus (ZIKV) strains can be classified into the ancestral African and contemporary Asian lineages, with the latter responsible for recent epidemics associated with neurological conditions. To understand how Asian strains lead to exacerbated disease, a crucial step is identifying genomic variations that affect infectivity and pathogenicity. Here we use two high-throughput sequencing approaches to assess RNA secondary structures and intramolecular RNA-RNA interactions in vivo for the RNA genomes of Asian and African ZIKV lineages. Our analysis identified functional RNA structural elements and a functional long-range intramolecular interaction specific for the Asian epidemic strains. Mutants that disrupt this extended RNA interaction between the 5' UTR and the E protein coding region reduce virus infectivity, which is partially rescued with compensatory mutants, restoring this RNA-RNA interaction. These findings illuminate the structural basis of ZIKV regulation and provide a resource for the discovery of RNA structural elements important for ZIKV infection.
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Affiliation(s)
- Pan Li
- MOE Key Laboratory of Bioinformatics, Beijing Advanced Innovation Center for Structural Biology, Center for Synthetic and Systems Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Yifan Wei
- MOE Key Laboratory of Bioinformatics, Beijing Advanced Innovation Center for Structural Biology, Center for Synthetic and Systems Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Miao Mei
- School of Pharmaceutical Sciences, Center for Infectious Disease Research, School of Medicine, Tsinghua University, Tsinghua-Peking Center for Life Sciences, Beijing 100084, China
| | - Lei Tang
- MOE Key Laboratory of Bioinformatics, Beijing Advanced Innovation Center for Structural Biology, Center for Synthetic and Systems Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Lei Sun
- MOE Key Laboratory of Bioinformatics, Beijing Advanced Innovation Center for Structural Biology, Center for Synthetic and Systems Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Wenze Huang
- MOE Key Laboratory of Bioinformatics, Beijing Advanced Innovation Center for Structural Biology, Center for Synthetic and Systems Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Jianyu Zhou
- Bioinformatics Division, BNRIST, Department of Computer Science and Technology, Tsinghua University, Beijing 100084, China
| | - Chunlin Zou
- Institutes of Biology and Medical Sciences, Jiangsu Key Laboratory of Infection and Immunity, Soochow University, Suzhou 215123, China
| | - Shaojun Zhang
- MOE Key Laboratory of Bioinformatics, Beijing Advanced Innovation Center for Structural Biology, Center for Synthetic and Systems Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Cheng-Feng Qin
- Department of Virology, State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China
| | - Tao Jiang
- Bioinformatics Division, BNRIST, Department of Computer Science and Technology, Tsinghua University, Beijing 100084, China; Department of Computer Science and Engineering, University of California, Riverside, CA 92521, USA
| | - Jianfeng Dai
- Institutes of Biology and Medical Sciences, Jiangsu Key Laboratory of Infection and Immunity, Soochow University, Suzhou 215123, China
| | - Xu Tan
- School of Pharmaceutical Sciences, Center for Infectious Disease Research, School of Medicine, Tsinghua University, Tsinghua-Peking Center for Life Sciences, Beijing 100084, China.
| | - Qiangfeng Cliff Zhang
- MOE Key Laboratory of Bioinformatics, Beijing Advanced Innovation Center for Structural Biology, Center for Synthetic and Systems Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China.
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35
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Ziv O, Gabryelska MM, Lun ATL, Gebert LFR, Sheu-Gruttadauria J, Meredith LW, Liu ZY, Kwok CK, Qin CF, MacRae IJ, Goodfellow I, Marioni JC, Kudla G, Miska EA. COMRADES determines in vivo RNA structures and interactions. Nat Methods 2018; 15:785-788. [PMID: 30202058 PMCID: PMC6168409 DOI: 10.1038/s41592-018-0121-0] [Citation(s) in RCA: 117] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Accepted: 07/20/2018] [Indexed: 01/07/2023]
Abstract
The structural flexibility of RNA underlies fundamental biological processes, but there are no methods for exploring the multiple conformations adopted by RNAs in vivo. We developed cross-linking of matched RNAs and deep sequencing (COMRADES) for in-depth RNA conformation capture, and a pipeline for the retrieval of RNA structural ensembles. Using COMRADES, we determined the architecture of the Zika virus RNA genome inside cells, and identified multiple site-specific interactions with human noncoding RNAs.
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Affiliation(s)
- Omer Ziv
- Wellcome Trust/Cancer Research UK Gurdon Institute, University of Cambridge, Cambridge, UK.
- Department of Genetics, University of Cambridge, Cambridge, UK.
| | - Marta M Gabryelska
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, Scotland, UK
| | - Aaron T L Lun
- Cancer Research UK Cambridge Institute, University of Cambridge, Cambridge, UK
| | - Luca F R Gebert
- Department of Integrative Structural and Computational Biology, the Scripps Research Institute, La Jolla, CA, USA
| | - Jessica Sheu-Gruttadauria
- Department of Integrative Structural and Computational Biology, the Scripps Research Institute, La Jolla, CA, USA
| | - Luke W Meredith
- Department of Pathology, University of Cambridge, Cambridge, UK
| | - Zhong-Yu Liu
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
- School of Medicine (Shenzhen), Sun Yat-sen University, Guangzhou, China
| | - Chun Kit Kwok
- Department of Chemistry, City University of Hong Kong, Hong Kong, China
| | - Cheng-Feng Qin
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Ian J MacRae
- Department of Integrative Structural and Computational Biology, the Scripps Research Institute, La Jolla, CA, USA
| | - Ian Goodfellow
- Department of Pathology, University of Cambridge, Cambridge, UK
| | - John C Marioni
- Cancer Research UK Cambridge Institute, University of Cambridge, Cambridge, UK
- European Molecular Biology Laboratory, European Bioinformatics Institute (EMBL-EBI), Cambridge, UK
- Wellcome Sanger Institute, Cambridge, UK
| | - Grzegorz Kudla
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, Scotland, UK.
| | - Eric A Miska
- Wellcome Trust/Cancer Research UK Gurdon Institute, University of Cambridge, Cambridge, UK.
- Department of Genetics, University of Cambridge, Cambridge, UK.
- Wellcome Sanger Institute, Cambridge, UK.
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36
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Zhao W, Xu Z, Zhang X, Yang M, Kang L, Liu R, Cui F. Genomic variations in the 3'-termini of Rice stripe virus in the rotation between vector insect and host plant. THE NEW PHYTOLOGIST 2018; 219:1085-1096. [PMID: 29882354 PMCID: PMC6055815 DOI: 10.1111/nph.15246] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Accepted: 05/01/2018] [Indexed: 06/08/2023]
Abstract
A large number of plant RNA viruses circulate between plants and insects. For RNA viruses, host alternations may impose a differential selective pressure on viral populations and induce variations in viral genomes. Here, we report the variations in the 3'-terminal regions of the multiple-segment RNA virus Rice stripe virus (RSV) that were discovered through de novo assembly of the genome using RNA sequencing data from infected host plants and vector insects. The newly assembled RSV genome contained 16- and 15-nt extensions at the 3'-termini of two genome segments compared with the published reference RSV genome. Our study demonstrated that these extensional sequences were consistently observed in two RSV isolates belonging to distinct genetic subtypes in RSV-infected rice, wheat and tobacco. Moreover, the de novo assembled genome of Southern rice black-streaked dwarf virus also contained 3'-terminal extensions in five RNA segments compared with the reference genome. Time course experiments confirmed that the 3'-terminal extensions of RSV were enriched in the vector insects, were gradually eliminated in the host plant and potentially affected viral replication. These findings indicate that variations in the 3'-termini of viral genomes may be different adaptive strategies for plant RNA viruses in insects and plants.
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Affiliation(s)
- Wan Zhao
- State Key Laboratory of Integrated Management of Pest Insects and RodentsInstitute of ZoologyChinese Academy of SciencesBeijing100101China
| | - Zhongtian Xu
- Shanghai Center for Plant Stress BiologyChinese Academy of SciencesShanghai201602China
- University of Chinese Academy of SciencesBeijing100049China
| | - Xiaoming Zhang
- State Key Laboratory of Integrated Management of Pest Insects and RodentsInstitute of ZoologyChinese Academy of SciencesBeijing100101China
| | - Meiling Yang
- State Key Laboratory of Integrated Management of Pest Insects and RodentsInstitute of ZoologyChinese Academy of SciencesBeijing100101China
| | - Le Kang
- State Key Laboratory of Integrated Management of Pest Insects and RodentsInstitute of ZoologyChinese Academy of SciencesBeijing100101China
| | - Renyi Liu
- Center for Agroforestry Mega Data Science and FAFU‐UCR Joint Center for Horticultural Biology and MetabolomicsHaixia Institute of Science and TechnologyFujian Agriculture and Forestry UniversityFuzhou350002China
| | - Feng Cui
- State Key Laboratory of Integrated Management of Pest Insects and RodentsInstitute of ZoologyChinese Academy of SciencesBeijing100101China
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Li L, Zhao H, Liu P, Li C, Quanquin N, Ji X, Sun N, Du P, Qin CF, Lu N, Cheng G. PARP12 suppresses Zika virus infection through PARP-dependent degradation of NS1 and NS3 viral proteins. Sci Signal 2018; 11:11/535/eaas9332. [PMID: 29921658 DOI: 10.1126/scisignal.aas9332] [Citation(s) in RCA: 76] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Zika virus infection stimulates a type I interferon (IFN) response in host cells, which suppresses viral replication. Type I IFNs exert antiviral effects by inducing the expression of hundreds of IFN-stimulated genes (ISGs). To screen for antiviral ISGs that restricted Zika virus replication, we individually knocked out 21 ISGs in A549 lung cancer cells and identified PARP12 as a strong inhibitor of Zika virus replication. Our findings suggest that PARP12 mediated the ADP-ribosylation of NS1 and NS3, nonstructural viral proteins that are involved in viral replication and modulating host defense responses. This modification of NS1 and NS3 triggered their proteasome-mediated degradation. These data increase our understanding of the antiviral activity of PARP12 and suggest a molecular basis for the potential development of therapeutics against Zika virus.
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Affiliation(s)
- Lili Li
- CAS Key Laboratory of Infection and Immunity, Institute of Biophysics, Chinese Academy of Sciences, Chaoyang District, Beijing 100101, China.,University of Chinese Academy of Sciences, Beijing 100101, China
| | - Hui Zhao
- Department of Virology, State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 10071, China
| | - Ping Liu
- CAS Key Laboratory of Infection and Immunity, Institute of Biophysics, Chinese Academy of Sciences, Chaoyang District, Beijing 100101, China
| | - Chunfeng Li
- Center for System Medicine, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100005, China.,Suzhou Institute of System Medicine, Suzhou, Jiangsu 215123, China
| | - Natalie Quanquin
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, CA 90095, USA
| | - Xue Ji
- Department of Virology, State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 10071, China
| | - Nina Sun
- CAS Key Laboratory of Infection and Immunity, Institute of Biophysics, Chinese Academy of Sciences, Chaoyang District, Beijing 100101, China.,University of Chinese Academy of Sciences, Beijing 100101, China
| | - Peishuang Du
- CAS Key Laboratory of Infection and Immunity, Institute of Biophysics, Chinese Academy of Sciences, Chaoyang District, Beijing 100101, China
| | - Cheng-Feng Qin
- Department of Virology, State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 10071, China
| | - Ning Lu
- CAS Key Laboratory of Infection and Immunity, Institute of Biophysics, Chinese Academy of Sciences, Chaoyang District, Beijing 100101, China.
| | - Genhong Cheng
- Center for System Medicine, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100005, China. .,Suzhou Institute of System Medicine, Suzhou, Jiangsu 215123, China.,Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, CA 90095, USA
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38
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Barrows NJ, Campos RK, Liao KC, Prasanth KR, Soto-Acosta R, Yeh SC, Schott-Lerner G, Pompon J, Sessions OM, Bradrick SS, Garcia-Blanco MA. Biochemistry and Molecular Biology of Flaviviruses. Chem Rev 2018; 118:4448-4482. [PMID: 29652486 DOI: 10.1021/acs.chemrev.7b00719] [Citation(s) in RCA: 189] [Impact Index Per Article: 31.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Flaviviruses, such as dengue, Japanese encephalitis, tick-borne encephalitis, West Nile, yellow fever, and Zika viruses, are critically important human pathogens that sicken a staggeringly high number of humans every year. Most of these pathogens are transmitted by mosquitos, and not surprisingly, as the earth warms and human populations grow and move, their geographic reach is increasing. Flaviviruses are simple RNA-protein machines that carry out protein synthesis, genome replication, and virion packaging in close association with cellular lipid membranes. In this review, we examine the molecular biology of flaviviruses touching on the structure and function of viral components and how these interact with host factors. The latter are functionally divided into pro-viral and antiviral factors, both of which, not surprisingly, include many RNA binding proteins. In the interface between the virus and the hosts we highlight the role of a noncoding RNA produced by flaviviruses to impair antiviral host immune responses. Throughout the review, we highlight areas of intense investigation, or a need for it, and potential targets and tools to consider in the important battle against pathogenic flaviviruses.
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Affiliation(s)
- Nicholas J Barrows
- Department of Biochemistry and Molecular Biology , University of Texas Medical Branch , Galveston , Texas 77555 , United States.,Department of Molecular Genetics and Microbiology , Duke University , Durham , North Carolina 27710 , United States
| | - Rafael K Campos
- Department of Biochemistry and Molecular Biology , University of Texas Medical Branch , Galveston , Texas 77555 , United States.,Department of Molecular Genetics and Microbiology , Duke University , Durham , North Carolina 27710 , United States
| | - Kuo-Chieh Liao
- Programme in Emerging Infectious Diseases , Duke-NUS Medical School , Singapore 169857 , Singapore
| | - K Reddisiva Prasanth
- Department of Biochemistry and Molecular Biology , University of Texas Medical Branch , Galveston , Texas 77555 , United States
| | - Ruben Soto-Acosta
- Department of Biochemistry and Molecular Biology , University of Texas Medical Branch , Galveston , Texas 77555 , United States
| | - Shih-Chia Yeh
- Programme in Emerging Infectious Diseases , Duke-NUS Medical School , Singapore 169857 , Singapore
| | - Geraldine Schott-Lerner
- Department of Biochemistry and Molecular Biology , University of Texas Medical Branch , Galveston , Texas 77555 , United States
| | - Julien Pompon
- Programme in Emerging Infectious Diseases , Duke-NUS Medical School , Singapore 169857 , Singapore.,MIVEGEC, IRD, CNRS, Université de Montpellier , Montpellier 34090 , France
| | - October M Sessions
- Programme in Emerging Infectious Diseases , Duke-NUS Medical School , Singapore 169857 , Singapore
| | - Shelton S Bradrick
- Department of Biochemistry and Molecular Biology , University of Texas Medical Branch , Galveston , Texas 77555 , United States
| | - Mariano A Garcia-Blanco
- Department of Biochemistry and Molecular Biology , University of Texas Medical Branch , Galveston , Texas 77555 , United States.,Programme in Emerging Infectious Diseases , Duke-NUS Medical School , Singapore 169857 , Singapore
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Oral Vaccination with a DNA Vaccine Encoding Capsid Protein of Duck Tembusu Virus Induces Protection Immunity. Viruses 2018; 10:v10040180. [PMID: 29642401 PMCID: PMC5923474 DOI: 10.3390/v10040180] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2018] [Revised: 04/01/2018] [Accepted: 04/04/2018] [Indexed: 12/26/2022] Open
Abstract
The emergence of duck tembusu virus (DTMUV), a new member of the Flavivirus genus, has caused great economical loss in the poultry industry in China. Since the outbreak and spread of DTMUV is hard to control in a clinical setting, an efficient and low-cost oral delivery DNA vaccine SL7207 (pVAX1-C) based on the capsid protein of DTMUV was developed and evaluated in this study. The antigen capsid protein was expressed from the DNA vaccine SL7207 (pVAX1-C), both in vitro and in vivo. The humoral and cellular immune responses in vivo were observed after oral immunization with the SL7207 (pVAX1-C) DNA vaccine. High titers of the specific antibody against the capsid protein and the neutralizing antibody against the DTMUV virus were both detected after inoculation. The ducks were efficiently protected from lethal DTMUV exposure by the SL7207 (pVAX1-C) vaccine in this experiment. Taken together, we demonstrated that the capsid protein of DTMUV possesses a strong immunogenicity against the DTMUV infection. Moreover, an oral delivery of the DNA vaccine SL7207 (pVAX1-C) utilizing Salmonella SL7207 was an efficient way to protect the ducks against DTMUV infection and provides an economic and fast vaccine delivery strategy for a large scale clinical use.
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40
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Flaviviral RNA Structures and Their Role in Replication and Immunity. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1062:45-62. [PMID: 29845524 DOI: 10.1007/978-981-10-8727-1_4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
More than simple vectors of genetic information, flaviviral RNAs have emerged as critical regulators of the virus life cycle. Viral RNAs regulate interactions with viral and cellular proteins in both, mosquito and mammalian hosts to ultimately influence processes as diverse as RNA replication, translation, packaging or pathogenicity. In this chapter, we will review the current knowledge of the role of sequence and structures in the flaviviral RNA in viral propagation and interaction with the host cell. We will also cover the increasing body of evidence linking viral non-coding RNAs with pathogenicity, host immunity and epidemic potential.
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41
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Characterization of cis-Acting RNA Elements of Zika Virus by Using a Self-Splicing Ribozyme-Dependent Infectious Clone. J Virol 2017; 91:JVI.00484-17. [PMID: 28814522 DOI: 10.1128/jvi.00484-17] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2017] [Accepted: 07/27/2017] [Indexed: 12/13/2022] Open
Abstract
Zika virus (ZIKV) has caused significant outbreaks and epidemics in the Americas recently, raising global concern due to its ability to cause microcephaly and other neurological complications. A stable and efficient infectious clone of ZIKV is urgently needed. However, the instability and toxicity of flavivirus cDNA clones in Escherichia coli hosts has hindered the development of ZIKV infectious clones. Here, using a novel self-splicing ribozyme-based strategy, we generated a stable infectious cDNA clone of a contemporary ZIKV strain imported from Venezuela to China in 2016. The constructed clone contained a modified version of the group II self-splicing intron P.li.LSUI2 near the junction between the E and NS1 genes, which were removed from the RNA transcripts by an easy-to-establish in vitro splicing reaction. Transfection of the spliced RNAs into BHK-21 cells led to the production of infectious progeny virus that resembled the parental virus. Finally, potential cis-acting RNA elements in ZIKV genomic RNA were identified based on this novel reverse genetics system, and the critical role of 5'-SLA promoter and 5'-3' cyclization sequences were characterized by a combination of different assays. Our results provide another stable and reliable reverse genetics system for ZIKV that will help study ZIKV infection and pathogenesis, and the novel self-splicing intron-based strategy could be further expanded for the construction of infectious clones from other emerging and reemerging flaviviruses.IMPORTANCE The ongoing Zika virus (ZIKV) outbreaks have drawn global concern due to the unexpected causal link to fetus microcephaly and other severe neurological complications. The infectious cDNA clones of ZIKV are critical for the research community to study the virus, understand the disease, and inform vaccine design and antiviral screening. A panel of existing technologies have been utilized to develop ZIKV infectious clones. Here, we successfully generated a stable infectious clone of a 2016 ZIKV strain using a novel self-splicing ribozyme-based technology that abolished the potential toxicity of ZIKV cDNA clones to the E. coli host. Moreover, two crucial cis-acting replication elements (5'-SLA and 5'-CS) of ZIKV were first identified using this novel reverse genetics system. This novel self-splicing ribozyme-based reverse genetics platform will be widely utilized in future ZIKV studies and provide insight for the development of infectious clones of other emerging viruses.
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42
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Li C, Zhu X, Ji X, Quanquin N, Deng YQ, Tian M, Aliyari R, Zuo X, Yuan L, Afridi SK, Li XF, Jung JU, Nielsen-Saines K, Qin FXF, Qin CF, Xu Z, Cheng G. Chloroquine, a FDA-approved Drug, Prevents Zika Virus Infection and its Associated Congenital Microcephaly in Mice. EBioMedicine 2017; 24:189-194. [PMID: 29033372 PMCID: PMC5652284 DOI: 10.1016/j.ebiom.2017.09.034] [Citation(s) in RCA: 109] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2017] [Revised: 09/20/2017] [Accepted: 09/26/2017] [Indexed: 01/09/2023] Open
Abstract
Zika virus (ZIKV) has become a global public health emergency due to its rapidly expanding range and its ability to cause severe congenital defects such as microcephaly. However, there are no FDA-approved therapies or vaccines against ZIKV infection. Through our screening of viral entry inhibitors, we found that chloroquine (CQ), a commonly used antimalarial and a FDA-approved drug that has also been repurposed against other pathogens, could significantly inhibit ZIKV infection in vitro, by blocking virus internalization. We also demonstrated that CQ attenuates ZIKV-associated morbidity and mortality in mice. Finally, we proved that CQ protects fetal mice from microcephaly caused by ZIKV infection. Our methodology of focusing on previously identified antivirals in screens for effectiveness against ZIKV proved to be a rapid and efficient means of discovering new ZIKV therapeutics. Selecting drugs that were previously FDA-approved, such as CQ, also improves the likelihood that they may more quickly reach stages of clinical testing and use by the public. 5 out 16 tested Ebola virus entry inhibitors can inhibit ZIKV entry efficiently Chloroquine can inhibit ZIKV internalization in vitro and reduce ZIKV-associated morbidity and mortality in mice Chloroquine prevents ZIKV-associated congenital microcephaly in mice
Zika virus (ZIKV) is an emerging virus which can cause birth defects, however there are currently no effective treatments or vaccines. We tested the effects of 16 verified Ebola virus cell entry inhibitors on ZIKV infection, and found that chloroquine (CQ) could prevent ZIKV infection in cell cultures, consistent with results from a previous study. We then demonstrated that CQ can reduce ZIKV-associated morbidity and mortality in mice. Most importantly, it protects fetal mice from microcephaly caused by ZIKV infection. Therefore, CQ is a potential drug which would be used to treat ZIKV infection after clinical test.
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Affiliation(s)
- Chunfeng Li
- Center for Systems Medicine, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100005; Suzhou Institute of Systems Medicine, Suzhou, Jiangsu 215123, China; Department of Virology, State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China
| | - Xingliang Zhu
- State Key Laboratory of Molecular Developmental Biology, CAS Center for Excellence in Brain Science and Intelligence Technology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Xue Ji
- Guangxi Medical University, Nanning 530021, China
| | - Natalie Quanquin
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, CA 90095, USA
| | - Yong-Qiang Deng
- Department of Virology, State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China
| | - Min Tian
- Beijing Traditional Medicine Chinese Hospital, Capital Medical University, Beijing 100069, China; Department of Virology, State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China
| | - Roghiyh Aliyari
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, CA 90095, USA
| | - Xiangyang Zuo
- Center for Systems Medicine, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100005; Suzhou Institute of Systems Medicine, Suzhou, Jiangsu 215123, China
| | - Ling Yuan
- State Key Laboratory of Molecular Developmental Biology, CAS Center for Excellence in Brain Science and Intelligence Technology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Shabbir Khan Afridi
- State Key Laboratory of Molecular Developmental Biology, CAS Center for Excellence in Brain Science and Intelligence Technology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Xiao-Feng Li
- Department of Virology, State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China
| | - Jae U Jung
- Department of Molecular Microbiology and Immunology, University of Southern California, Zilkha Neurogenetic Institute, 1501, 11 San Pablo Street, Los Angeles, CA 90033, USA
| | - Karin Nielsen-Saines
- Division of Pediatric Infectious Diseases, David Geffen School of Medicine, University of California, Los Angeles, Marion Davies Children's Health Center, 10833 Le Conte Avenue, Los Angeles, CA 90095, USA
| | - Frank Xiao-Feng Qin
- Center for Systems Medicine, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100005; Suzhou Institute of Systems Medicine, Suzhou, Jiangsu 215123, China.
| | - Cheng-Feng Qin
- Department of Virology, State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China; Guangxi Medical University, Nanning 530021, China.
| | - Zhiheng Xu
- State Key Laboratory of Molecular Developmental Biology, CAS Center for Excellence in Brain Science and Intelligence Technology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China; Parkinson's Disease Center, Beijing Institute for Brain Disorders, Beijing 100101, China.
| | - Genhong Cheng
- Center for Systems Medicine, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100005; Suzhou Institute of Systems Medicine, Suzhou, Jiangsu 215123, China; Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, CA 90095, USA.
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43
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Piyasena TBH, Setoh YX, Hobson-Peters J, Newton ND, Bielefeldt-Ohmann H, McLean BJ, Vet LJ, Khromykh AA, Hall RA. Infectious DNAs derived from insect-specific flavivirus genomes enable identification of pre- and post-entry host restrictions in vertebrate cells. Sci Rep 2017; 7:2940. [PMID: 28592864 PMCID: PMC5462777 DOI: 10.1038/s41598-017-03120-1] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Accepted: 04/24/2017] [Indexed: 02/06/2023] Open
Abstract
Flaviviruses such as West Nile virus (WNV), dengue virus and Zika virus are mosquito-borne pathogens that cause significant human diseases. A novel group of insect-specific flaviviruses (ISFs), which only replicate in mosquitoes, have also been identified. However, little is known about the mechanisms of ISF host restriction. We report the generation of infectious cDNA from two Australian ISFs, Parramatta River virus (PaRV) and Palm Creek virus (PCV). Using circular polymerase extension cloning (CPEC) with a modified OpIE2 insect promoter, infectious cDNA was generated and transfected directly into mosquito cells to produce infectious virus indistinguishable from wild-type virus. When infectious PaRV cDNA under transcriptional control of a mammalian promoter was used to transfect mouse embryo fibroblasts, the virus failed to initiate replication even when cell entry steps were by-passed and the type I interferon response was lacking. We also used CPEC to generate viable chimeric viruses between PCV and WNV. Analysis of these hybrid viruses revealed that ISFs are also restricted from replication in vertebrate cells at the point of entry. The approaches described here to generate infectious ISF DNAs and chimeric viruses provide unique tools to further dissect the mechanisms of their host restriction.
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Affiliation(s)
- Thisun B H Piyasena
- Australian Infectious Diseases Research Centre, School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, 4072, Queensland, Australia
| | - Yin X Setoh
- Australian Infectious Diseases Research Centre, School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, 4072, Queensland, Australia
| | - Jody Hobson-Peters
- Australian Infectious Diseases Research Centre, School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, 4072, Queensland, Australia
| | - Natalee D Newton
- Australian Infectious Diseases Research Centre, School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, 4072, Queensland, Australia
| | - Helle Bielefeldt-Ohmann
- Australian Infectious Diseases Research Centre, School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, 4072, Queensland, Australia
| | - Breeanna J McLean
- Australian Infectious Diseases Research Centre, School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, 4072, Queensland, Australia
| | - Laura J Vet
- Australian Infectious Diseases Research Centre, School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, 4072, Queensland, Australia
| | - Alexander A Khromykh
- Australian Infectious Diseases Research Centre, School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, 4072, Queensland, Australia.
| | - Roy A Hall
- Australian Infectious Diseases Research Centre, School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, 4072, Queensland, Australia.
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44
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Fernández-Sanlés A, Ríos-Marco P, Romero-López C, Berzal-Herranz A. Functional Information Stored in the Conserved Structural RNA Domains of Flavivirus Genomes. Front Microbiol 2017; 8:546. [PMID: 28421048 PMCID: PMC5376627 DOI: 10.3389/fmicb.2017.00546] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Accepted: 03/15/2017] [Indexed: 02/05/2023] Open
Abstract
The genus Flavivirus comprises a large number of small, positive-sense single-stranded, RNA viruses able to replicate in the cytoplasm of certain arthropod and/or vertebrate host cells. The genus, which has some 70 member species, includes a number of emerging and re-emerging pathogens responsible for outbreaks of human disease around the world, such as the West Nile, dengue, Zika, yellow fever, Japanese encephalitis, St. Louis encephalitis, and tick-borne encephalitis viruses. Like other RNA viruses, flaviviruses have a compact RNA genome that efficiently stores all the information required for the completion of the infectious cycle. The efficiency of this storage system is attributable to supracoding elements, i.e., discrete, structural units with essential functions. This information storage system overlaps and complements the protein coding sequence and is highly conserved across the genus. It therefore offers interesting potential targets for novel therapeutic strategies. This review summarizes our knowledge of the features of flavivirus genome functional RNA domains. It also provides a brief overview of the main achievements reported in the design of antiviral nucleic acid-based drugs targeting functional genomic RNA elements.
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Affiliation(s)
- Alba Fernández-Sanlés
- Department of Molecular Biology, Instituto de Parasitología y Biomedicina "López-Neyra," Consejo Superior de Investigaciones Científicas (IPBLN-CSIC)Granada, Spain
| | - Pablo Ríos-Marco
- Department of Molecular Biology, Instituto de Parasitología y Biomedicina "López-Neyra," Consejo Superior de Investigaciones Científicas (IPBLN-CSIC)Granada, Spain
| | - Cristina Romero-López
- Department of Molecular Biology, Instituto de Parasitología y Biomedicina "López-Neyra," Consejo Superior de Investigaciones Científicas (IPBLN-CSIC)Granada, Spain
| | - Alfredo Berzal-Herranz
- Department of Molecular Biology, Instituto de Parasitología y Biomedicina "López-Neyra," Consejo Superior de Investigaciones Científicas (IPBLN-CSIC)Granada, Spain
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45
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Yun SI, Lee YM. Zika virus: An emerging flavivirus. J Microbiol 2017; 55:204-219. [PMID: 28243937 DOI: 10.1007/s12275-017-7063-6] [Citation(s) in RCA: 69] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Accepted: 02/15/2017] [Indexed: 01/18/2023]
Abstract
Zika virus (ZIKV) is a previously little-known flavivirus closely related to Japanese encephalitis, West Nile, dengue, and yellow fever viruses, all of which are primarily transmitted by blood-sucking mosquitoes. Since its discovery in Uganda in 1947, ZIKV has continued to expand its geographic range, from equatorial Africa and Asia to the Pacific Islands, then further afield to South and Central America and the Caribbean. Currently, ZIKV is actively circulating not only in much of Latin America and its neighbors but also in parts of the Pacific Islands and Southeast Asia. Although ZIKV infection generally causes only mild symptoms in some infected individuals, it is associated with a range of neuroimmunological disorders, including Guillain-Barré syndrome, meningoencephalitis, and myelitis. Recently, maternal ZIKV infection during pregnancy has been linked to neonatal malformations, resulting in various degrees of congenital abnormalities, microcephaly, and even abortion. Despite its emergence as an important public health problem, however, little is known about ZIKV biology, and neither vaccine nor drug is available to control ZIKV infection. This article provides a brief introduction to ZIKV with a major emphasis on its molecular virology, in order to help facilitate the development of diagnostics, therapeutics, and vaccines.
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Affiliation(s)
- Sang-Im Yun
- Department of Animal, Dairy, and Veterinary Sciences, Utah State University, Logan, UT, 84322-4815, USA
| | - Young-Min Lee
- Department of Animal, Dairy, and Veterinary Sciences, Utah State University, Logan, UT, 84322-4815, USA. .,Utah Science Technology and Research, College of Agriculture and Applied Sciences, Utah State University, Logan, UT, 84322-4815, USA.
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46
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Wang CC, Hsu YC, Wu HC, Wu HN. Insights into the coordinated interplay of the sHP hairpin and its co-existing and mutually-exclusive dengue virus terminal RNA elements for viral replication. Virology 2017; 505:56-70. [PMID: 28235683 DOI: 10.1016/j.virol.2017.02.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2016] [Revised: 02/08/2017] [Accepted: 02/10/2017] [Indexed: 12/15/2022]
Abstract
Terminal RNA elements of the dengue virus (DENV) genome are necessary for balanced stability of linear and circular conformations during replication. We examined the small hairpin (sHP) and co-existing and mutually-exclusive terminal RNA elements by mutagenesis analysis, compensatory mutation screening, and by probing with RNA fragments to explore localized RNA folding and long-range RNA interactions. We found that the first base pair of the sHP and the stability of SLB and the 3'SL bottom stem affected circularization; sHPgc/C10631G+G10644C prohibited circularization, sHPuG accelerated and stabilized 5'-to-3' RNA hybridization, while C94A and A97G and C10649 mutations loosened SLB and 3'SL, respectively, for circularization. sHPuG+C10649G induced circularization and impeded replication, whereas point mutations that loosened the UAR or DAR ds region, strengthened the sHP, or reinforced the 3'SL bottom stem, rescued the replication deficiency. Overall, we reveal structural and sequence features and interplay of DENV genome terminal RNA elements essential to viral replication.
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Affiliation(s)
- Chun-Chung Wang
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan, Republic of China
| | - Yu-Chen Hsu
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan, Republic of China
| | - Hsin-Chieh Wu
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan, Republic of China; Faculty of Life Sciences and Institute of Genomic Sciences, National Yang-Ming University, Taipei, Taiwan, Republic of China
| | - Huey-Nan Wu
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan, Republic of China.
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47
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Li XF, Li XD, Deng CL, Dong HL, Zhang QY, Ye Q, Ye HQ, Huang XY, Deng YQ, Zhang B, Qin CF. Visualization of a neurotropic flavivirus infection in mouse reveals unique viscerotropism controlled by host type I interferon signaling. Am J Cancer Res 2017; 7:912-925. [PMID: 28382163 PMCID: PMC5381253 DOI: 10.7150/thno.16615] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Accepted: 12/17/2016] [Indexed: 01/07/2023] Open
Abstract
Flavivirus includes a large group of human pathogens with medical importance. Especially, neurotropic flaviviruses capable of invading central and peripheral nervous system, e.g. Japanese encephalitis virus (JEV) and Zika virus (ZIKV), are highly pathogenic to human and constitute major global health problems. However, the dynamic dissemination and pathogenesis of neurotropic flavivirus infections remain largely unknown. Here, using JEV as a model, we rationally designed and constructed a recombinant reporter virus that stably expressed Renilla luciferase (Rluc). The resulting JEV reporter virus (named Rluc-JEV) and parental JEV exhibited similar replication and infection characteristics, and the magnitude of Rluc activity correlated well with progeny viral production in vitro and in vivo. By using in vivo bioluminescence imaging (BLI) technology, we dissected the replication and dissemination dynamics of JEV infection in mice upon different inoculation routes. Interestingly, besides replicating in mouse brain, Rluc-JEV predominantly invaded the abdominal organs in mice with typical viscerotropism. Further tests in mice deficient in type I interferon (IFN) receptors demonstrated robust and prolonged viral replication in the intestine, spleen, liver, kidney and other abdominal organs. Combined with histopathological and immunohistochemical results, the host type I IFN signaling was evidenced as the major barrier to the viscerotropism and pathogenicity of this neurotropic flavivirus. Additionally, the Rluc-JEV platform was readily adapted for efficacy assay of known antiviral compounds and a live JE vaccine. Collectively, our study revealed abdominal organs as important targets of JEV infection in mice and profiled the unique viscerotropism trait controlled by the host type I IFN signaling. This in vivo visualization technology described here provides a powerful tool for testing antiviral agents and vaccine candidates for flaviviral infection.
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48
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Medin CL, Rothman AL. Zika Virus: The Agent and Its Biology, With Relevance to Pathology. Arch Pathol Lab Med 2016; 141:33-42. [PMID: 27763795 DOI: 10.5858/arpa.2016-0409-ra] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Once obscure, Zika virus (ZIKV) has attracted significant medical and scientific attention in the past year because of large outbreaks associated with the recent introduction of this virus into the Western hemisphere. In particular, the occurrence of severe congenital infections and cases of Guillain-Barré syndrome has placed this virus squarely in the eyes of clinical and anatomic pathologists. This review article provides a basic introduction to ZIKV, its genetics, its structural characteristics, and its biology. A multidisciplinary effort will be essential to establish clinicopathologic correlations of the basic virology of ZIKV in order to advance development of diagnostics, therapeutics, and vaccines.
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Affiliation(s)
| | - Alan L Rothman
- From the Institute for Immunology and Informatics, Department of Cell and Molecular Biology, University of Rhode Island, Providence. Drs Medin and Rothman both contributed equally to the manuscript
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49
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Liu ZY, Li XF, Jiang T, Deng YQ, Ye Q, Zhao H, Yu JY, Qin CF. Viral RNA switch mediates the dynamic control of flavivirus replicase recruitment by genome cyclization. eLife 2016; 5. [PMID: 27692070 PMCID: PMC5101012 DOI: 10.7554/elife.17636] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2016] [Accepted: 09/30/2016] [Indexed: 12/23/2022] Open
Abstract
Viral replicase recruitment and long-range RNA interactions are essential for RNA virus replication, yet the mechanism of their interplay remains elusive. Flaviviruses include numerous important human pathogens, e.g., dengue virus (DENV) and Zika virus (ZIKV). Here, we revealed a highly conserved, conformation-tunable cis-acting element named 5′-UAR-flanking stem (UFS) in the flavivirus genomic 5′ terminus. We demonstrated that the UFS was critical for efficient NS5 recruitment and viral RNA synthesis in different flaviviruses. Interestingly, stabilization of the DENV UFS impaired both genome cyclization and vRNA replication. Moreover, the UFS unwound in response to genome cyclization, leading to the decreased affinity of NS5 for the viral 5′ end. Thus, we propose that the UFS is switched by genome cyclization to regulate dynamic RdRp binding for vRNA replication. This study demonstrates that the UFS enables communication between flavivirus genome cyclization and RdRp recruitment, highlighting the presence of switch-like mechanisms among RNA viruses. DOI:http://dx.doi.org/10.7554/eLife.17636.001 Flaviviruses include a large family of viruses that are harmful to human health, such as dengue virus, West Nile virus and Zika virus. Understanding the details of the life cycle of these viruses is important for better controlling and treating the diseases that they cause. The genetic information of flaviviruses is stored in single-stranded molecules of RNA. To form new copies of a virus, the RNA must be replicated in a process that involves two critical steps. First, an enzyme called viral RNA polymerase NS5 must be recruited to a specific end of the RNA strand (known as the 5′ end). Then, the ends of the RNA strand bind together to form a circular loop. However, little is known about whether these two processes are linked, or how they are regulated. Using bioinformatics, biochemical and reverse genetics approaches, Liu et al. have now identified a new section of RNA in the 5′ end of the flavivirus RNA, named the 5′-UAR-flanking stem (or UFS for short), which is critical for viral replication. The UFS plays an important role in efficiently recruiting the NS5 viral RNA polymerase to the 5′ end of the flavivirus RNA. After the RNA forms a circle, the UFS unwinds. This makes the NS5 polymerase less likely to bind to the 5′ end of the RNA. Stabilizing the structure of the UFS impairs the ability of the RNA strand to form a circle, and hence reduces the ability of the RNA to replicate. Thus, the UFS links and enables communication between the processes that form the flavivirus RNA into a circle and that recruit the viral RNA polymerase to the RNA. The structural basis of the interaction between the flavivirus RNA 5′ end, including the UFS element, and the viral RNA polymerase now deserves further investigation. It will be also important to explore whether other types of viruses regulate their replication via a similar mechanism. DOI:http://dx.doi.org/10.7554/eLife.17636.002
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Affiliation(s)
- Zhong-Yu Liu
- Department of Virology, Beijing Institute of Microbiology and Epidemiology, Beijing, China.,State Key Laboratory of Pathogen and Biosecurity, Beijing, China
| | - Xiao-Feng Li
- Department of Virology, Beijing Institute of Microbiology and Epidemiology, Beijing, China.,State Key Laboratory of Pathogen and Biosecurity, Beijing, China
| | - Tao Jiang
- Department of Virology, Beijing Institute of Microbiology and Epidemiology, Beijing, China.,State Key Laboratory of Pathogen and Biosecurity, Beijing, China
| | - Yong-Qiang Deng
- Department of Virology, Beijing Institute of Microbiology and Epidemiology, Beijing, China.,State Key Laboratory of Pathogen and Biosecurity, Beijing, China
| | - Qing Ye
- Department of Virology, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Hui Zhao
- Department of Virology, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Jiu-Yang Yu
- Department of Virology, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Cheng-Feng Qin
- Department of Virology, Beijing Institute of Microbiology and Epidemiology, Beijing, China.,State Key Laboratory of Pathogen and Biosecurity, Beijing, China
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50
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Abstract
Dengue virus affects hundreds of millions of people each year around the world, causing a tremendous social and economic impact on affected countries. The aim of this review is to summarize our current knowledge of the functions, structure, and interactions of the viral capsid protein. The primary role of capsid is to package the viral genome. There are two processes linked to this function: the recruitment of the viral RNA during assembly and the release of the genome during infection. Although particle assembly takes place on endoplasmic reticulum membranes, capsid localizes in nucleoli and lipid droplets. Why capsid accumulates in these locations during infection remains unknown. In this review, we describe available data and discuss new ideas on dengue virus capsid functions and interactions. We believe that a deeper understanding of how the capsid protein works during infection will create opportunities for novel antiviral strategies, which are urgently needed to control dengue virus infections.
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Affiliation(s)
- Laura A Byk
- Fundación Instituto Leloir-National Research Council for Science and Technology (CONICET), Buenos Aires 1405, Argentina;
| | - Andrea V Gamarnik
- Fundación Instituto Leloir-National Research Council for Science and Technology (CONICET), Buenos Aires 1405, Argentina;
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