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Development and Characterization of a Genetically Stable Infectious Clone for a Genotype I Isolate of Dengue Virus Serotype 1. Viruses 2022; 14:v14092073. [PMID: 36146879 PMCID: PMC9501529 DOI: 10.3390/v14092073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Revised: 09/15/2022] [Accepted: 09/16/2022] [Indexed: 11/16/2022] Open
Abstract
Dengue virus (DENV) is primarily transmitted by the bite of an infected mosquito of Aedes aegypti and Aedes albopictus, and symptoms caused may range from mild dengue fever to severe dengue hemorrhagic fever and dengue shock syndrome. Reverse genetic system represents a valuable tool for the study of DENV virology, infection, pathogenesis, etc. Here, we generated and characterized an eukaryotic-activated full-length infectious cDNA clone for a DENV serotype 1 (DENV-1) isolate, D19044, collected in 2019. Initially, nearly the full genome was determined by sequencing overlapping RT-PCR products, and was classified to be genotype I DENV-1. D19044 wild-type cDNA clone (D19044_WT) was assembled by four subgenomic fragments, in a specific order, into a low-copy vector downstream the CMV promoter. D19044_WT released the infectious virus at a low level (1.26 × 103 focus forming units per milliliter [FFU/mL]) following plasmid transfection of BHK-21 cells. Further adaptation by consecutive virus passages up to passage 37, and seven amino acid substitutions (7M) were identified from passage-recovered viruses. The addition of 7M (D19044_7M) greatly improved viral titer (7.5 × 104 FFU/mL) in transfected BHK-21 culture, and virus infections in 293T, Huh7.5.1, and C6/36 cells were also efficient. D19044_7M plasmid was genetically stable in transformant bacteria after five transformation-purification cycles, which did not change the capacity of producing infectious virus. Moreover, the D19044_7M virus was inhibited by mycophenolic acid in a dose-dependent manner. In conclusion, we have developed a DNA-launched full-length infectious clone for a genotype I isolate of DENV-1, with genetic stability in transformant bacteria, thus providing a useful tool for the study of DENV-1.
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Guo Y, Wang H, Xu S, Zhou H, Zhou C, Fu S, Cheng M, Li F, Deng Y, Li X, Wang H, Qin CF. Recovery and Genetic Characterization of a West Nile Virus Isolate from China. Virol Sin 2020; 36:113-121. [PMID: 32632819 DOI: 10.1007/s12250-020-00246-x] [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: 05/09/2020] [Accepted: 05/25/2020] [Indexed: 11/27/2022] Open
Abstract
West Nile virus (WNV) is an important neurotropic flavivirus that is widely distributed globally. WNV strain XJ11129 was first isolated in Xinjiang, China, and its genetic and biological characteristics remain largely unknown. In this study, phylogenetic and sequence analyses revealed that XJ11129 belongs to lineage 1a and shares high genetic identity with the highly pathogenic strain NY99. Then, the full-length genomic cDNA of XJ11129 was amplified and assembled using a modified Gibson assembly (GA) method. The virus (named rXJ11129) was successfully rescued in days following this method. Compared with other wild-type WNV isolates, rXJ11129 exhibited virulence indistinguishable from that of the NY99 strain in vivo. In summary, the genomic and virulence phenotypes of rXJ11129 were characterized in vivo and in vitro, and these data will improve the understanding of the spread and pathogenesis of this reemerging virus.
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Affiliation(s)
- Yan Guo
- Department of Virology, State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Academy of Military Medical Sciences (AMMS), Beijing, 100071, China
| | - Hongjiang Wang
- PLA Strategic Support Force Characteristic Medical Center, Beijing, 100071, China
| | - Songtao Xu
- Department of Arbovirus, NHC Key Laboratory of Biosafety, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, 102206, China
- State Key Laboratory for Infectious Disease Prevention and Control, Chinese Center for Disease Control and Prevention, Beijing, 102206, China
| | - Hangyu Zhou
- Suzhou Institute of System Medicine, Chinese Academy of Medical Sciences and Peking Union Medical College, Suzhou, 215000, China
| | - Chao Zhou
- Department of Immunology, Key Laboratory of Immune Microenvironment and Disease, Nanjing Medical University, Nanjing, 211166, China
| | - Shihong Fu
- Department of Arbovirus, NHC Key Laboratory of Biosafety, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, 102206, China
- State Key Laboratory for Infectious Disease Prevention and Control, Chinese Center for Disease Control and Prevention, Beijing, 102206, China
| | - Mengli Cheng
- Department of Virology, State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Academy of Military Medical Sciences (AMMS), Beijing, 100071, China
| | - Fan Li
- Department of Arbovirus, NHC Key Laboratory of Biosafety, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, 102206, China
- State Key Laboratory for Infectious Disease Prevention and Control, Chinese Center for Disease Control and Prevention, Beijing, 102206, China
| | - Yongqiang Deng
- Department of Virology, State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Academy of Military Medical Sciences (AMMS), Beijing, 100071, China
| | - Xiaofeng Li
- Department of Virology, State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Academy of Military Medical Sciences (AMMS), Beijing, 100071, China
| | - Huanyu Wang
- Department of Arbovirus, NHC Key Laboratory of Biosafety, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, 102206, China.
- State Key Laboratory for Infectious Disease Prevention and Control, Chinese Center for Disease Control and Prevention, Beijing, 102206, 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 (AMMS), Beijing, 100071, China.
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Santos JJDS, Magalhães T, Silva Junior JVJ, Silva ANMRD, Cordeiro MT, Gil LHVG. Full-length infectious clone of a low passage dengue virus serotype 2 from Brazil. Mem Inst Oswaldo Cruz 2015. [PMID: 26200712 PMCID: PMC4569833 DOI: 10.1590/0074-02760150053] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Full-length dengue virus (DENV) cDNA clones are an invaluable tool for many studies,
including those on the development of attenuated or chimeric vaccines and on
host-virus interactions. Furthermore, the importance of low passage DENV infectious
clones should be highlighted, as these may harbour critical and unique
strain-specific viral components from field-circulating isolates. The successful
construction of a functional Brazilian low passage DENV serotype 2 full-length clone
through homologous recombination reported here supports the use of a strategy that
has been shown to be highly useful by our group for the development of flavivirus
infectious clones and replicons.
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Affiliation(s)
- Jefferson José da Silva Santos
- Laboratório de Virologia e Terapia Experimental, Centro de Pesquisas Aggeu Magalhães, Fundação Oswaldo Cruz, Recife, PE, BR
| | - Tereza Magalhães
- Laboratório de Virologia e Terapia Experimental, Centro de Pesquisas Aggeu Magalhães, Fundação Oswaldo Cruz, Recife, PE, BR
| | | | | | - Marli Tenório Cordeiro
- Laboratório de Virologia e Terapia Experimental, Centro de Pesquisas Aggeu Magalhães, Fundação Oswaldo Cruz, Recife, PE, BR
| | - Laura Helena Vega Gonzales Gil
- Laboratório de Virologia e Terapia Experimental, Centro de Pesquisas Aggeu Magalhães, Fundação Oswaldo Cruz, Recife, PE, BR
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Flavivirus reverse genetic systems, construction techniques and applications: a historical perspective. Antiviral Res 2014; 114:67-85. [PMID: 25512228 PMCID: PMC7173292 DOI: 10.1016/j.antiviral.2014.12.007] [Citation(s) in RCA: 91] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2014] [Revised: 11/26/2014] [Accepted: 12/03/2014] [Indexed: 12/20/2022]
Abstract
The study of flaviviruses, which cause some of the most important emerging tropical and sub-tropical human arbovirus diseases, has greatly benefited from the use of reverse genetic systems since its first development for yellow fever virus in 1989. Reverse genetics technology has completely revolutionized the study of these viruses, making it possible to manipulate their genomes and evaluate the direct effects of these changes on their biology and pathogenesis. The most commonly used reverse genetics system is the infectious clone technology. Whilst flavivirus infectious clones provide a powerful tool, their construction as full-length cDNA molecules in bacterial vectors can be problematic, laborious and time consuming, because they are often unstable, contain unwanted induced substitutions and may be toxic for bacteria due to viral protein expression. The incredible technological advances that have been made during the past 30years, such as the use of PCR or new sequencing methods, have allowed the development of new approaches to improve preexisting systems or elaborate new strategies that overcome these problems. This review summarizes the evolution and major technical breakthroughs in the development of flavivirus reverse genetics technologies and their application to the further understanding and control of these viruses and their diseases.
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Manzano M, Padmanabhan R. Targeted mutagenesis of dengue virus type 2 replicon RNA by yeast in vivo recombination. Methods Mol Biol 2014; 1138:151-60. [PMID: 24696336 DOI: 10.1007/978-1-4939-0348-1_10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
The use of cDNA infectious clones or subgenomic replicons is indispensable in studying flavivirus biology. Mutating nucleotides or amino acid residues gives important clues to their function in the viral life cycle. However, a major challenge to the establishment of a reverse genetics system for flaviviruses is the instability of their nucleotide sequences in Escherichia coli. Thus, direct cloning using conventional restriction enzyme-based procedures usually leads to unwanted rearrangements of the construct. In this chapter, we discuss a cloning strategy that bypasses traditional cloning procedures. We take advantage of the observations from previous studies that (1) unstable sequences in bacteria can be cloned in eukaryotic systems and (2) Saccharomyces cerevisiae has a well-studied genetics system to introduce sequences using homologous recombination. We describe a protocol to perform targeted mutagenesis in a subgenomic dengue virus 2 replicon. Our method makes use of homologous recombination in yeast using a linearized replicon and a PCR product containing the desired mutation. Constructs derived from this method can be propagated in E. coli with improved stability. Thus, yeast in vivo recombination provides an excellent strategy to genetically engineer flavivirus infectious clones or replicons because this system is compatible with inherently unstable sequences of flaviviruses and is not restricted by the limitations of traditional cloning procedures.
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Affiliation(s)
- Mark Manzano
- Department of Microbiology-Immunology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
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Abstract
Dengue virus (DENV) is an emerging mosquito-borne human pathogen that affects millions of individuals each year by causing severe and potentially fatal syndromes. Despite intense research efforts, no approved vaccine or antiviral therapy is yet available. Overcoming this limitation requires detailed understanding of the intimate relationship between the virus and its host cell, providing the basis to devise optimal prophylactic and therapeutic treatment options. With the advent of novel high-throughput technologies including functional genomics, transcriptomics, proteomics, and lipidomics, new important insights into the DENV replication cycle and the interaction of this virus with its host cell have been obtained. In this chapter, we provide a comprehensive overview on the current status of the DENV research field, covering every step of the viral replication cycle with a particular focus on virus-host cell interaction. We will also review specific chemical inhibitors targeting cellular factors and processes of relevance for the DENV replication cycle and their possible exploitation for the development of next generation antivirals.
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Pu SY, Wu RH, Tsai MH, Yang CC, Chang CM, Yueh A. A novel approach to propagate flavivirus infectious cDNA clones in bacteria by introducing tandem repeat sequences upstream of virus genome. J Gen Virol 2014; 95:1493-1503. [DOI: 10.1099/vir.0.064915-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Despite tremendous efforts to improve the methodology for constructing flavivirus infectious cDNAs, the manipulation of flavivirus cDNAs remains a difficult task in bacteria. Here, we successfully propagated DNA-launched type 2 dengue virus (DENV2) and Japanese encephalitis virus (JEV) infectious cDNAs by introducing seven repeats of the tetracycline-response element (7×TRE) and a minimal cytomegalovirus (CMVmin) promoter upstream of the viral genome. Insertion of the 7×TRE-CMVmin sequence upstream of the DENV2 or JEV genome decreased the cryptic E. coli promoter (ECP) activity of the viral genome in bacteria, as measured using fusion constructs containing DENV2 or JEV segments and the reporter gene Renilla luciferase in an empty vector. The growth kinetics of recombinant viruses derived from DNA-launched DENV2 and JEV infectious cDNAs were similar to those of parental viruses. Similarly, RNA-launched DENV2 infectious cDNAs were generated by inserting 7×TRE-CMVmin, five repeats of the GAL4 upstream activating sequence, or five repeats of BamHI linkers upstream of the DENV2 genome. All three tandem repeat sequences decreased the ECP activity of the DENV2 genome in bacteria. Notably, 7×TRE-CMVmin stabilized RNA-launched JEV infectious cDNAs and reduced the ECP activity of the JEV genome in bacteria. The growth kinetics of recombinant viruses derived from RNA-launched DENV2 and JEV infectious cDNAs displayed patterns similar to those of the parental viruses. These results support a novel methodology for constructing flavivirus infectious cDNAs, which will facilitate research in virology, viral pathogenesis and vaccine development of flaviviruses and other RNA viruses.
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Affiliation(s)
- Szu-Yuan Pu
- Graduate Institute of Life Sciences, National Defense Medical Center, Taipei, Taiwan, R.O.C
- Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Miaoli 350, Taiwan, R.O.C
| | - Ren-Huang Wu
- Graduate Institute of Life Sciences, National Defense Medical Center, Taipei, Taiwan, R.O.C
- Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Miaoli 350, Taiwan, R.O.C
| | - Ming-Han Tsai
- Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Miaoli 350, Taiwan, R.O.C
| | - Chi-Chen Yang
- Graduate Institute of Life Sciences, National Defense Medical Center, Taipei, Taiwan, R.O.C
- Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Miaoli 350, Taiwan, R.O.C
| | - Chung-Ming Chang
- Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Miaoli 350, Taiwan, R.O.C
| | - Andrew Yueh
- Graduate Institute of Life Sciences, National Defense Medical Center, Taipei, Taiwan, R.O.C
- Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Miaoli 350, Taiwan, R.O.C
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Live attenuated tetravalent dengue virus host range vaccine is immunogenic in African green monkeys following a single vaccination. J Virol 2014; 88:6729-42. [PMID: 24696467 DOI: 10.1128/jvi.00541-14] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
UNLABELLED The causative agent of dengue fever, dengue virus (DENV), is transmitted by mosquitoes, and as distribution of these insects has expanded, so has dengue-related disease. DENV is a member of the Flaviviridae family and has 4 distinct serotypes (DENV-1, -2, -3, and -4). No lasting cross protection is afforded to heterologous serotypes following infection by any one of the individual serotypes. The presence of nonneutralizing antibodies to one serotype can facilitate the occurrence of more-severe dengue hemorrhagic fever through immune enhancement upon infection with a second serotype. For this reason, the development of a safe, tetravalent vaccine to produce a balanced immune response to all four serotypes is critical. We have developed a novel approach to produce safe and effective live-attenuated vaccines for DENV and other insect-borne viruses. Host range (HR) mutants of each DENV serotype were created by truncating transmembrane domain 1 of the E protein and selecting for strains of DENV that replicated well in insect cells but not mammalian cells. These vaccine strains were tested for immunogenicity in African green monkeys (AGMs). No vaccine-related adverse events occurred. The vaccine strains were confirmed to be attenuated in vivo by infectious center assay (ICA). Analysis by 50% plaque reduction neutralization test (PRNT50) established that by day 62 postvaccination, 100% of animals seroconverted to DENV-1, -2, -3, and -4. Additionally, the DENV HR tetravalent vaccine (HR-Tet) showed a tetravalent anamnestic immune response in 100% (16/16) of AGMs after challenge with wild-type (WT) DENV strains. IMPORTANCE We have generated a live attenuated viral (LAV) vaccine capable of eliciting a strong immune response in African green monkeys (AGMs) in a single dose. This vaccine is delivered by injecting one of four attenuated serotypes into each limb of the animal. 100% of animals given the vaccine generated antibodies against all 4 serotypes, and this response was found to be balanced in nature. This is also one of the first studies of dengue in AGMs, and our study suggests that viremia and antibody response in AGMs may be similar to those seen in DENV infection in humans.
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Usme-Ciro JA, Lopera JA, Enjuanes L, Almazán F, Gallego-Gomez JC. Development of a novel DNA-launched dengue virus type 2 infectious clone assembled in a bacterial artificial chromosome. Virus Res 2013; 180:12-22. [PMID: 24342140 PMCID: PMC7114509 DOI: 10.1016/j.virusres.2013.12.001] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2013] [Revised: 11/29/2013] [Accepted: 12/03/2013] [Indexed: 12/05/2022]
Abstract
We cloned a DENV-2 infectious cDNA into a BAC under the control of the CMV promoter. We assessed the production of infectious particles. We rescued infectious viruses after serial passages in C6/36 cells. Parental and recombinant viruses were similar in plaque and syncytia phenotypes.
Major progress in Dengue virus (DENV) biology has resulted from the use of infectious clones obtained through reverse genetics. The construction of these clones is commonly based on high- or low-copy number plasmids, yeast artificial chromosomes, yeast-Escherichia coli shuttle vectors, and bacterial artificial chromosomes (BACs). Prokaryotic promoters have consistently been used for the transcription of these clones. The goal of this study was to develop a novel DENV infectious clone in a BAC under the control of the cytomegalovirus immediate-early promoter and to generate a virus with the fusion envelope-green fluorescent protein in an attempt to track virus infection. The transfection of Vero cells with a plasmid encoding the DENV infectious clone facilitated the recovery of infectious particles that increased in titer after serial passages in C6/36 cells. The plaque size and syncytia phenotypes of the recombinant virus were similar to those of the parental virus. Despite the observation of autonomous replication and the detection of low levels of viral genome after two passages, the insertion of green fluorescent protein and Renilla luciferase reporter genes negatively impacted virus rescue. To the best of our knowledge, this is the first study using a DENV infectious clone under the control of the cytomegalovirus promoter to facilitate the recovery of recombinant viruses without the need for in vitro transcription. This novel molecular clone will be useful for establishing the molecular basis of replication, assembly, and pathogenesis, evaluating potential antiviral drugs, and the development of vaccine candidates for attenuated recombinant viruses.
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Affiliation(s)
- Jose A Usme-Ciro
- Molecular and Translational Medicine Group, Facultad de Medicina, Universidad de Antioquia, Calle 70 No. 52-21, Medellín, Colombia; Viral Vector Core & Gene Therapy, Neuroscience Group, Facultad de Medicina, Sede de Investigación Universitaria-SIU, Universidad de Antioquia, Calle 70 No. 52-21, Medellín, Colombia.
| | - Jaime A Lopera
- Viral Vector Core & Gene Therapy, Neuroscience Group, Facultad de Medicina, Sede de Investigación Universitaria-SIU, Universidad de Antioquia, Calle 70 No. 52-21, Medellín, Colombia
| | - Luis Enjuanes
- Department of Molecular and Cell Biology, Centro Nacional de Biotecnología (CNB-CSIC), Campus Universidad Autónoma, Darwin 3, 28049 Madrid, Spain
| | - Fernando Almazán
- Department of Molecular and Cell Biology, Centro Nacional de Biotecnología (CNB-CSIC), Campus Universidad Autónoma, Darwin 3, 28049 Madrid, Spain
| | - Juan C Gallego-Gomez
- Molecular and Translational Medicine Group, Facultad de Medicina, Universidad de Antioquia, Calle 70 No. 52-21, Medellín, Colombia; Viral Vector Core & Gene Therapy, Neuroscience Group, Facultad de Medicina, Sede de Investigación Universitaria-SIU, Universidad de Antioquia, Calle 70 No. 52-21, Medellín, Colombia.
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Yamashita A, Sasaki T, Kurosu T, Yasunaga T, Ikuta K. Origin and distribution of divergent dengue virus: novel database construction and phylogenetic analyses. Future Virol 2013. [DOI: 10.2217/fvl.13.99] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Dengue virus (DENV), a mosquito-borne agent that exists as four serotypes (DENV-1–4), induces dengue illness. DENV has a positive-sense, ssRNA genome of approximately 11 kb that encodes a capsid protein, a premembrane protein and an envelope glycoprotein, in addition to seven nonstructural proteins. These individual genes show sequence variations that can be analyzed phylogenetically to yield several genotypes within each serotype. Here, the sequences of individual DENV genes were collected and used to construct a novel DENV database. This database was then used to characterize the evolution of individual genotypes in several countries. Interestingly, the database provided evidence for recombination between two or three different genotypes to yield new genotypes. This novel database will be available on the internet and is expected to be highly useful for dengue genetic studies, including phylogenetic analyses.
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Affiliation(s)
- Akifumi Yamashita
- Research Institute for Microbial Diseases, Osaka University, Suita, Osaka 565-0871, Japan
- National Institute of Infectious Diseases, Tokyo 162-8640, Japan
| | - Tadahiro Sasaki
- Research Institute for Microbial Diseases, Osaka University, Suita, Osaka 565-0871, Japan
| | - Takeshi Kurosu
- Research Institute for Microbial Diseases, Osaka University, Suita, Osaka 565-0871, Japan
| | - Teruo Yasunaga
- Research Institute for Microbial Diseases, Osaka University, Suita, Osaka 565-0871, Japan
| | - Kazuyoshi Ikuta
- Research Institute for Microbial Diseases, Osaka University, Suita, Osaka 565-0871, Japan
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Rodriguez-Roche R, Gould EA. Understanding the dengue viruses and progress towards their control. BIOMED RESEARCH INTERNATIONAL 2013; 2013:690835. [PMID: 23936833 PMCID: PMC3722981 DOI: 10.1155/2013/690835] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 03/13/2013] [Accepted: 05/08/2013] [Indexed: 01/12/2023]
Abstract
Traditionally, the four dengue virus serotypes have been associated with fever, rash, and the more severe forms, haemorrhagic fever and shock syndrome. As our knowledge as well as understanding of these viruses increases, we now recognise not only that they are causing increasing numbers of human infections but also that they may cause neurological and other clinical complications, with sequelae or fatal consequences. In this review we attempt to highlight some of these features in the context of dengue virus pathogenesis. We also examine some of the efforts currently underway to control this "scourge" of the tropical and subtropical world.
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Affiliation(s)
- Rosmari Rodriguez-Roche
- Pedro Kouri Tropical Medicine Institute, WHO/PAHO Collaborating Centre for the Study of Dengue and Its Vector, Havana, Cuba.
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12
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The small molecules AZD0530 and dasatinib inhibit dengue virus RNA replication via Fyn kinase. J Virol 2013; 87:7367-81. [PMID: 23616652 DOI: 10.1128/jvi.00632-13] [Citation(s) in RCA: 93] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
In this study, we characterized the antiviral mechanism of action of AZD0530 and dasatinib, two pharmacological inhibitors of host kinases, that also inhibit dengue virus (DV) infection. Using Northern blot and reporter replicon assays, we demonstrated that both small molecules inhibit the DV2 infectious cycle at the step of steady-state RNA replication. In order to identify the cellular target of AZD0530 and dasatinib mediating this anti-DV2 activity, we examined the effects of RNA interference (RNAi)-mediated depletion of the major kinases known to be inhibited by these small molecules. We determined that Fyn kinase, a target of both AZD0530 and dasatinib, is involved in DV2 RNA replication and is probably a major mediator of the anti-DV activity of these compounds. Furthermore, serial passaging of DV2 in the presence of dasatinib led to the identification of a mutation in the transmembrane domain 3 of the NS4B protein that overcomes the inhibition of RNA replication by AZD0530, dasatinib, and Fyn RNAi. Although we observed that dasatinib also inhibits DV2 particle assembly and/or secretion, this activity does not appear to be mediated by Src-family kinases. Together, our results suggest that AZD0530 and dasatinib inhibit DV at the step of viral RNA replication and demonstrate a critical role for Fyn kinase in this viral process. The antiviral activity of these compounds in vitro makes them useful pharmacological tools to validate Fyn or other host kinases as anti-DV targets in vivo.
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A novel bacterium-free method for generation of flavivirus infectious DNA by circular polymerase extension reaction allows accurate recapitulation of viral heterogeneity. J Virol 2012; 87:2367-72. [PMID: 23236063 DOI: 10.1128/jvi.03162-12] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
A novel bacterium-free approach for rapid assembly of flavivirus infectious cDNAs using circular polymerase extension reaction was applied to generate infectious cDNA for the virulent New South Wales isolate of the Kunjin strain of West Nile virus (KUNV) that recently emerged in Australia. Recovered virus recapitulated the genetic heterogeneity present in the original isolate. The approach was utilized to generate viral mutants with designed phenotypic properties and to identify E protein glycosylation as one of the virulence determinants.
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Bowen DM, Lewis JA, Lu W, Schein CH. Simplifying complex sequence information: a PCP-consensus protein binds antibodies against all four Dengue serotypes. Vaccine 2012; 30:6081-7. [PMID: 22863657 DOI: 10.1016/j.vaccine.2012.07.042] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2012] [Revised: 07/13/2012] [Accepted: 07/18/2012] [Indexed: 12/15/2022]
Abstract
Designing proteins that reflect the natural variability of a pathogen is essential for developing novel vaccines and drugs. Flaviviruses, including Dengue (DENV) and West Nile (WNV), evolve rapidly and can "escape" neutralizing monoclonal antibodies by mutation. Designing antigens that represent many distinct strains is important for DENV, where infection with a strain from one of the four serotypes may lead to severe hemorrhagic disease on subsequent infection with a strain from another serotype. Here, a DENV physicochemical property (PCP)-consensus sequence was derived from 671 unique sequences from the Flavitrack database. PCP-consensus proteins for domain 3 of the envelope protein (EdomIII) were expressed from synthetic genes in Escherichia coli. The ability of the purified consensus proteins to bind polyclonal antibodies generated in response to infection with strains from each of the four DENV serotypes was determined. The initial consensus protein bound antibodies from DENV-1-3 in ELISA and Western blot assays. This sequence was altered in 3 steps to incorporate regions of maximum variability, identified as significant changes in the PCPs, characteristic of DENV-4 strains. The final protein was recognized by antibodies against all four serotypes. Two amino acids essential for efficient binding to all DENV antibodies are part of a discontinuous epitope previously defined for a neutralizing monoclonal antibody. The PCP-consensus method can significantly reduce the number of experiments required to define a multivalent antigen, which is particularly important when dealing with pathogens that must be tested at higher biosafety levels.
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Affiliation(s)
- David M Bowen
- Computational Biology, Sealy Center for Structural Biology and Molecular Biophysics, Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX 77555-0857, United States
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Rodriguez-Roche R, Villegas E, Cook S, Poh Kim PAW, Hinojosa Y, Rosario D, Villalobos I, Bendezu H, Hibberd ML, Guzman MG. Population structure of the dengue viruses, Aragua, Venezuela, 2006-2007. Insights into dengue evolution under hyperendemic transmission. INFECTION GENETICS AND EVOLUTION 2011; 12:332-44. [PMID: 22197765 PMCID: PMC3919160 DOI: 10.1016/j.meegid.2011.12.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/07/2011] [Revised: 12/08/2011] [Accepted: 12/10/2011] [Indexed: 12/16/2022]
Abstract
During the past three decades there has been a notable increase in dengue disease severity in Venezuela. Nevertheless, the population structure of the viruses being transmitted in this country is not well understood. Here, we present a molecular epidemiological study on dengue viruses (DENV) circulating in Aragua State, Venezuela during 2006-2007. Twenty-one DENV full-length genomes representing all of the four serotypes were amplified and sequenced directly from the serum samples. Notably, only DENV-2 was associated with severe disease. Phylogenetic trees constructed using Bayesian methods indicated that only one genotype was circulating for each serotype. However, extensive viral genetic diversity was found in DENV isolated from the same area during the same period, indicating significant in situ evolution since the introduction of these genotypes. Collectively, the results suggest that the non-structural (NS) proteins may play an important role in DENV evolution, particularly NS1, NS2A and NS4B proteins. The phylogenetic data provide evidence to suggest that multiple introductions of DENV have occurred from the Latin American region into Venezuela and vice versa. The implications of the significant viral genetic diversity generated during hyperendemic transmission, particularly in NS protein are discussed and considered in the context of future development and use of human monoclonal antibodies as antivirals and tetravalent vaccines.
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A single amino acid in nonstructural protein NS4B confers virulence to dengue virus in AG129 mice through enhancement of viral RNA synthesis. J Virol 2011; 85:7775-87. [PMID: 21632767 DOI: 10.1128/jvi.00665-11] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Dengue (DEN) is a mosquito-borne viral disease that has become an increasing economic and health burden for the tropical and subtropical world. The lack of an appropriate animal model of DEN has greatly impeded the study of its pathogenesis and the development of vaccines/antivirals. We recently reported a DEN virus 2 (DENV-2) strain (D2Y98P) that lethally infects immunocompromised AG129 mice, resulting in organ damage or dysfunction and increased vascular permeability, hallmarks of severe DEN in patients (G. K. Tan et al., PLoS Negl. Trop. Dis. 4:e672, 2010). Here we report the identification of one critical virulence determinant of strain D2Y98P. By mutagenesis, we showed that a Phe-to-Leu alteration at amino acid position 52 in nonstructural protein NS4B completely abolished the pathogenicity of the D2Y98P virus, as evidenced by a lack of lethality and the absence of histological signs of disease, which correlated with reduced viral titers and intact vascular permeability. Conversely, a Leu-to-Phe alteration at position 52 of NS4B in nonvirulent DENV-2 strain TSV01 led to 80% lethality and increased viremia. The NS4B(Phe52) viruses displayed enhanced RNA synthesis in mammalian cells but not in mosquito cells. The increased viral RNA synthesis was independent of the ability of NS4B to interfere with the host type I interferon response. Overall, our results demonstrate that Phe at position 52 in NS4B confers virulence in mice on two independent DENV-2 strains through enhancement of viral RNA synthesis. In addition to providing further insights into the functional role of NS4B protein, our findings further support a direct relationship between viral loads and DEN pathogenesis in vivo, consistent with observations in DEN patients.
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Evolution of attenuating mutations in dengue-2 strain S16803 PDK50 vaccine and comparison of growth kinetics with parent virus. Virus Genes 2011; 43:18-26. [PMID: 21461924 DOI: 10.1007/s11262-011-0602-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2011] [Accepted: 03/21/2011] [Indexed: 10/18/2022]
Abstract
A live-attenuated dengue-2 virus strain S16803 vaccine candidate that is immunogenic and safe in humans was derived by 50 passages in primary dog kidney (PDK) cells. To identify mutations associated with attenuation of the dengue-2 PDK50 vaccine strain, we determined the nucleotide changes that arose during PDK passage of the dengue-2 virus. Thirteen mutations distinguished the PDK50 virus from low-passage parent resulting in amino acid substitutions in the premembrane (E89G), envelope (E202K, N203D), nonstructural proteins NS1 (A43T), NS2A (L181F), NS2B (I26V), and NS4B (I/T108T, L112F). In addition, the PDK50 virus contained a C to T change of nucleotide 57 in the 5' non-coding region and four silent mutations of nucleotides 591, 987, 6471, and 8907. An infectious PDK50 cDNA clone virus was produced and characterized for growth kinetics in monkey (LLC-MK(2), Vero) and mosquito (C6/36) cells. Identification of mutations in the vaccine strain and availability of an infectious clone will permit systematic analysis of the importance of individual or collective mutations on attenuation of dengue virus.
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Successful propagation of flavivirus infectious cDNAs by a novel method to reduce the cryptic bacterial promoter activity of virus genomes. J Virol 2011; 85:2927-41. [PMID: 21228244 DOI: 10.1128/jvi.01986-10] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Reverse genetics is a powerful tool to study single-stranded RNA viruses. Despite tremendous efforts having been made to improve the methodology for constructing flavivirus cDNAs, the cause of toxicity of flavivirus cDNAs in bacteria remains unknown. Here we performed mutational analysis studies to identify Escherichia coli promoter (ECP) sequences within nucleotides (nt) 1 to 3000 of the dengue virus type 2 (DENV2) and Japanese encephalitis virus (JEV) genomes. Eight and four active ECPs were demonstrated within nt 1 to 3000 of the DENV2 and JEV genomes, respectively, using fusion constructs containing DENV2 or JEV segments and empty vector reporter gene Renilla luciferase. Full-length DENV2 and JEV cDNAs were obtained by inserting mutations reducing their ECP activity in bacteria without altering amino acid sequences. A severe cytopathic effect occurred when BHK21 cells were transfected with in vitro-transcribed RNAs from either a DENV2 cDNA clone with multiple silent mutations within the prM-E-NS1 region of dengue genome or a JEV cDNA clone with an A-to-C mutation at nt 90 of the JEV genome. The virions derived from the DENV2 or JEV cDNA clone exhibited infectivities similar to those of their parental viruses in C6/36 and BHK21 cells. A cis-acting element essential for virus replication was revealed by introducing silent mutations into the central portion (nt 160 to 243) of the core gene of DENV2 infectious cDNA or a subgenomic DENV2 replicon clone. This novel strategy of constructing DENV2 and JEV infectious clones could be applied to other flaviviruses or pathogenic RNA viruses to facilitate research in virology, viral pathogenesis, and vaccine development.
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