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Sistrom M, Andrews H, Edwards DL. Comparative genomics of Japanese encephalitis virus shows low rates of recombination and a small subset of codon positions under episodic diversifying selection. PLoS Negl Trop Dis 2024; 18:e0011459. [PMID: 38295106 PMCID: PMC10861042 DOI: 10.1371/journal.pntd.0011459] [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: 06/15/2023] [Revised: 02/12/2024] [Accepted: 01/11/2024] [Indexed: 02/02/2024] Open
Abstract
Orthoflavivirus japonicum (JEV) is the dominant cause of viral encephalitis in the Asian region with 100,000 cases and 25,000 deaths reported annually. The genome is comprised of a single polyprotein that encodes three structural and seven non-structural proteins. We collated a dataset of 349 complete genomes from a number of public databases, and analysed the data for recombination, evolutionary selection and phylogenetic structure. There are low rates of recombination in JEV, subsequently recombination is not a major evolutionary force shaping JEV. We found a strong overall signal of purifying selection in the genome, which is the main force affecting the evolutionary dynamics in JEV. There are also a small number of genomic sites under episodic diversifying selection, especially in the envelope protein and non-structural proteins 3 and 5. Overall, these results support previous analyses of JEV evolutionary genomics and provide additional insight into the evolutionary processes shaping the distribution and adaptation of this important pathogenic arbovirus.
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Affiliation(s)
- Mark Sistrom
- Department of Industry, Trade and Tourism, Berrimah Veterinary Laboratories, Darwin, Australia
- Research Institute for the Environment and Livelihoods, Faculty of Science and Technology, Charles Darwin University, Casuarina, Australia
| | - Hannah Andrews
- Department of Industry, Trade and Tourism, Berrimah Veterinary Laboratories, Darwin, Australia
| | - Danielle L. Edwards
- Research Institute for the Environment and Livelihoods, Faculty of Science and Technology, Charles Darwin University, Casuarina, Australia
- Department of Natural Sciences, Museum and Art Gallery of the Northern Territory, Darwin, Australia
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2
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Sukhorukov GA, Paramonov AI, Lisak OV, Kozlova IV, Bazykin GA, Neverov AD, Karan LS. The Baikal subtype of tick-borne encephalitis virus is evident of recombination between Siberian and Far-Eastern subtypes. PLoS Negl Trop Dis 2023; 17:e0011141. [PMID: 36972237 PMCID: PMC10079218 DOI: 10.1371/journal.pntd.0011141] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Revised: 04/06/2023] [Accepted: 02/06/2023] [Indexed: 03/29/2023] Open
Abstract
Tick-borne encephalitis virus (TBEV) is a flavivirus which causes an acute or sometimes chronic infection that frequently has severe neurological consequences, and is a major public health threat in Eurasia. TBEV is genetically classified into three distinct subtypes; however, at least one group of isolates, the Baikal subtype, also referred to as “886-84-like”, challenges this classification. Baikal TBEV is a persistent group which has been repeatedly isolated from ticks and small mammals in the Buryat Republic, Irkutsk and Trans-Baikal regions of Russia for several decades. One case of meningoencephalitis with a lethal outcome caused by this subtype has been described in Mongolia in 2010. While recombination is frequent in Flaviviridae, its role in the evolution of TBEV has not been established. Here, we isolate and sequence four novel Baikal TBEV samples obtained in Eastern Siberia. Using a set of methods for inference of recombination events, including a newly developed phylogenetic method allowing for formal statistical testing for such events in the past, we find robust support for a difference in phylogenetic histories between genomic regions, indicating recombination at origin of the Baikal TBEV. This finding extends our understanding of the role of recombination in the evolution of this human pathogen.
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Affiliation(s)
- Grigorii A. Sukhorukov
- Center of Life Sciences, Skolkovo Institute of Science and Technology, Skolkovo, Russia
- * E-mail: (GAS); (GAB); (ADN)
| | - Alexey I. Paramonov
- Laboratory of molecular Epidemiology and genetic diagnosis, Scientific Centre for Family Health and Human Reproduction Problems, Irkutsk, Russia
| | - Oksana V. Lisak
- Laboratory of molecular Epidemiology and genetic diagnosis, Scientific Centre for Family Health and Human Reproduction Problems, Irkutsk, Russia
| | - Irina V. Kozlova
- Laboratory of molecular Epidemiology and genetic diagnosis, Scientific Centre for Family Health and Human Reproduction Problems, Irkutsk, Russia
| | - Georgii A. Bazykin
- Center of Life Sciences, Skolkovo Institute of Science and Technology, Skolkovo, Russia
- Laboratory of Molecular Evolution, Kharkevich Institute for Information Transmission Problems of the RAS, Moscow, Russia
- * E-mail: (GAS); (GAB); (ADN)
| | - Alexey D. Neverov
- HSE University, Moscow, Russia
- Department of Molecular Diagnostics, Central Research Institute for Epidemiology, Moscow, Russia
- * E-mail: (GAS); (GAB); (ADN)
| | - Lyudmila S. Karan
- Department of Molecular Diagnostics, Central Research Institute for Epidemiology, Moscow, Russia
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3
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Gaunt MW, Pettersson JHO, Kuno G, Gaunt B, de Lamballerie X, Gould EA. Widespread Interspecific Phylogenetic Tree Incongruence Between Mosquito-Borne and Insect-Specific Flaviviruses at Hotspots Originally Identified in Zika Virus. Virus Evol 2022; 8:veac027. [PMID: 35591877 PMCID: PMC9113262 DOI: 10.1093/ve/veac027] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2020] [Revised: 10/22/2021] [Accepted: 04/17/2022] [Indexed: 11/16/2022] Open
Abstract
Intraspecies (homologous) phylogenetic incongruence, or ‘tree conflict’ between different loci within the same genome of mosquito-borne flaviviruses (MBFV), was first identified in dengue virus (DENV) and subsequently in Japanese encephalitis virus (JEV), St Louis encephalitis virus, and Zika virus (ZIKV). Recently, the first evidence of phylogenetic incongruence between interspecific members of the MBFV was reported in ZIKV and its close relative, Spondweni virus. Uniquely, these hybrid proteomes were derived from four incongruent trees involving an Aedes-associated DENV node (1 tree) and three different Culex-associated flavivirus nodes (3 trees). This analysis has now been extended across a wider spectrum of viruses within the MBFV lineage targeting the breakpoints between phylogenetic incongruent loci originally identified in ZIKV. Interspecies phylogenetic incongruence at these breakpoints was identified in 10 of 50 viruses within the MBFV lineage, representing emergent Aedes and Culex-associated viruses including JEV, West Nile virus, yellow fever virus, and insect-specific viruses. Thus, interspecies phylogenetic incongruence is widespread amongst the flaviviruses and is robustly associated with the specific breakpoints that coincide with the interspecific phylogenetic incongruence previously identified, inferring they are ‘hotspots’. The incongruence amongst the emergent MBFV group was restricted to viruses within their respective associated epidemiological boundaries. This MBFV group was RY-coded at the third codon position (‘wobble codon’) to remove transition saturation. The resulting ‘wobble codon’ trees presented a single topology for the entire genome that lacked any robust evidence of phylogenetic incongruence between loci. Phylogenetic interspecific incongruence was therefore observed for exactly the same loci between amino acid and the RY-coded ‘wobble codon’ alignments and this incongruence represented either a major part, or the entire genomes. Maximum likelihood codon analysis revealed positive selection for the incongruent lineages. Positive selection could result in the same locus producing two opposing trees. These analyses for the clinically important MBFV suggest that robust interspecific phylogenetic incongruence resulted from amino acid selection. Convergent or parallel evolutions are evolutionary processes that would explain the observation, whilst interspecific recombination is unlikely.
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Affiliation(s)
- Michael W Gaunt
- London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, United Kingdom
| | - John H-O Pettersson
- Department of Medical Biochemistry and Microbiology, Zoonosis Science Center, Uppsala University, Uppsala, Sweden
- Sydney Institute for Infectious Diseases, School of Life and Environmental Sciences and School of Medical Sciences, the University of Sydney, Sydney, New South Wales 2006, Australia
| | - Goro Kuno
- Formerly, Centers for Disease Control, Fort Collins, CO 80521, USA
| | - Bill Gaunt
- Aeon-sys, MBCS Kensington Road, Barnsley S75 2TU, UK
| | - Xavier de Lamballerie
- UMR “Unité des Virus Emergents”, Aix-Marseille Université-IRD 190-Inserm 1207-IHU Méditerranée Infection, Marseille, France
- APHM Public Hospitals of Marseille, Institut Hospitalo-Universitaire Méditerranée Infection, Marseille, France
| | - Ernest A Gould
- UMR “Unité des Virus Emergents”, Aix-Marseille Université-IRD 190-Inserm 1207-IHU Méditerranée Infection, Marseille, France
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Fang Y, Li XS, Zhang W, Xue JB, Wang JZ, Yin SQ, Li SG, Li XH, Zhang Y. Molecular epidemiology of mosquito-borne viruses at the China-Myanmar border: discovery of a potential epidemic focus of Japanese encephalitis. Infect Dis Poverty 2021; 10:57. [PMID: 33902684 PMCID: PMC8073957 DOI: 10.1186/s40249-021-00838-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Accepted: 04/08/2021] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND Mosquito-based arbovirus surveillance can serve as an early warning in evaluating the status of mosquito-borne virus prevalence and thus prevent local outbreaks. Although Tengchong County in Yunnan Province-which borders Myanmar-is abundant and diverse in mosquitoes, very few mosquito-based arbovirus investigations have been conducted in the recent decade. Herein, this study aims to evaluate the presence and the diffusion of mosquito-borne pathogens, currently prevalent in this region. METHODS We collected 9486 mosquitoes, representing eight species, with Culex tritaeniorhynchus and Anopheles sinensis as the dominant species, during high mosquito activity seasons (July-October) in Tengchong, in 2018. Samples collected from 342 pools were tested using reverse-transcription PCR to determine the species, distribution, and infection rates of virus and parasite, and further analyze their genotypes, phylogenetic relationships, infection rate, and potential pathogenicity. RESULTS Fifteen Japanese encephalitis virus (JEV) strains from Cx. tritaeniorhynchus pools were detected. Seven strains of insect-specific flaviviruses (ISFVs), including two Aedes flavivirus (AeFV) and Yunnan Culex flavivirus strains each, one Culex theileri flavivirus, Yamadai flavivirus (YDFV) and Anopheles-associated flavivirus (AAFV) strains each were detected in Aedes albopictus, Cx. tritaeniorhynchus, Cx. vagans, Cx. pseudovihnui, and An. sinensis pools, respectively. The whole-genome was successfully amplified in one strain of JEV and AeFV each. Phylogenetic analysis using the E gene placed all the newly detected JEV strains into the GI-b genotype. They showed highly nucleotide identities, and were most closely related to the strain detected in Tengchong in 2010. The comparison of the E protein of JEV strains and vaccine-derived strain, showed six amino residue differences. The bias-corrected maximum likelihood estimation values (and 95% confidence interval) for JEV in Cx. tritaeniorhynchus collected in Tengchong in 2018 were 2.4 (1.4-3.9). CONCLUSIONS A potential Japanese encephalitis epidemic focus with the abundance of host mosquitoes and high JEV infection rate was observed in Tengchong. In addition, at least five species of ISFVs co-circulate in this area. This study highlights the importance of widespread and sustained mosquito-based arbovirus surveillance in local areas to prevent the transmission of JEV, and other emerging/re-emerging mosquito-borne pathogens.
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Affiliation(s)
- Yuan Fang
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention (Chinese Center for Tropical Diseases Research); NHC Key Laboratory of Parasite and Vector Biology; WHO Collaborating Centre for Tropical Diseases; National Center for International Research on Tropical Diseases, Shanghai, China
- School of Global Health, Chinese Center for Tropical Diseases Research, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Xi-Shang Li
- Tengchong County Center for Disease Control and Prevention, Tengchong, Yunnan, China
| | - Wei Zhang
- Zichuan District Center for Disease Control and Prevention, Shandong, Zibo, China
| | - Jing-Bo Xue
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention (Chinese Center for Tropical Diseases Research); NHC Key Laboratory of Parasite and Vector Biology; WHO Collaborating Centre for Tropical Diseases; National Center for International Research on Tropical Diseases, Shanghai, China
- School of Global Health, Chinese Center for Tropical Diseases Research, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Jia-Zhi Wang
- Tengchong County Center for Disease Control and Prevention, Tengchong, Yunnan, China
| | - Shou-Qin Yin
- Zichuan District Center for Disease Control and Prevention, Shandong, Zibo, China
| | - Sheng-Guo Li
- Tengchong County Center for Disease Control and Prevention, Tengchong, Yunnan, China
| | - Xin-He Li
- Tengchong County Center for Disease Control and Prevention, Tengchong, Yunnan, China
| | - Yi Zhang
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention (Chinese Center for Tropical Diseases Research); NHC Key Laboratory of Parasite and Vector Biology; WHO Collaborating Centre for Tropical Diseases; National Center for International Research on Tropical Diseases, Shanghai, China.
- School of Global Health, Chinese Center for Tropical Diseases Research, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
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5
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Clark JJ, Gilray J, Orton RJ, Baird M, Wilkie G, Filipe ADS, Johnson N, McInnes CJ, Kohl A, Biek R. Population genomics of louping ill virus provide new insights into the evolution of tick-borne flaviviruses. PLoS Negl Trop Dis 2020; 14:e0008133. [PMID: 32925939 PMCID: PMC7515184 DOI: 10.1371/journal.pntd.0008133] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Revised: 09/24/2020] [Accepted: 08/07/2020] [Indexed: 12/30/2022] Open
Abstract
The emergence and spread of tick-borne arboviruses pose an increased challenge to human and animal health. In Europe this is demonstrated by the increasingly wide distribution of tick-borne encephalitis virus (TBEV, Flavivirus, Flaviviridae), which has recently been found in the United Kingdom (UK). However, much less is known about other tick-borne flaviviruses (TBFV), such as the closely related louping ill virus (LIV), an animal pathogen which is endemic to the UK and Ireland, but which has been detected in other parts of Europe including Scandinavia and Russia. The emergence and potential spatial overlap of these viruses necessitates improved understanding of LIV genomic diversity, geographic spread and evolutionary history. We sequenced a virus archive composed of 22 LIV isolates which had been sampled throughout the UK over a period of over 80 years. Combining this dataset with published virus sequences, we detected no sign of recombination and found low diversity and limited evidence for positive selection in the LIV genome. Phylogenetic analysis provided evidence of geographic clustering as well as long-distance movement, including movement events that appear recent. However, despite genomic data and an 80-year time span, we found that the data contained insufficient temporal signal to reliably estimate a molecular clock rate for LIV. Additional analyses revealed that this also applied to TBEV, albeit to a lesser extent, pointing to a general problem with phylogenetic dating for TBFV. The 22 LIV genomes generated during this study provide a more reliable LIV phylogeny, improving our knowledge of the evolution of tick-borne flaviviruses. Our inability to estimate a molecular clock rate for both LIV and TBEV suggests that temporal calibration of tick-borne flavivirus evolution should be interpreted with caution and highlight a unique aspect of these viruses which may be explained by their reliance on tick vectors. Tick-borne pathogens represent a major emerging threat to public health and in recent years have been expanding into new areas. LIV is a neglected virus endemic to the UK and Ireland (though it has been detected in Scandinavia and Russia) which is closely related to the major human pathogen TBEV, but predominantly causes disease in sheep and grouse. The recent detection of TBEV in the UK, which has also emerged elsewhere in Europe, requires more detailed understanding of the spread and sequence diversity of LIV. This could be important for diagnosis and vaccination, but also to improve our understanding of the evolution and emergence of these tick-borne viruses. Here we describe the sequencing of 22 LIV isolates which have been sampled from several host species across the past century. We have utilised this dataset to investigate the evolutionary pressures that LIV is subjected to and have explored the evolution of LIV using phylogenetic analysis. Crucially we were unable to estimate a reliable molecular clock rate for LIV and found that this problem also extends to a larger phylogeny of TBEV sequences. This work highlights a previously unknown caveat of tick-borne flavivirus evolutionary analysis which may be important for understanding the evolution of these important pathogens.
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Affiliation(s)
- Jordan J. Clark
- MRC-University of Glasgow Centre for Virus Research, Glasgow, United Kingdom
- Moredun Research Institute, Edinburgh, United Kingdom
- * E-mail: (JC); (RB)
| | - Janice Gilray
- Moredun Research Institute, Edinburgh, United Kingdom
| | - Richard J. Orton
- MRC-University of Glasgow Centre for Virus Research, Glasgow, United Kingdom
| | - Margaret Baird
- MRC-University of Glasgow Centre for Virus Research, Glasgow, United Kingdom
| | - Gavin Wilkie
- MRC-University of Glasgow Centre for Virus Research, Glasgow, United Kingdom
| | - Ana da Silva Filipe
- MRC-University of Glasgow Centre for Virus Research, Glasgow, United Kingdom
| | - Nicholas Johnson
- Animal and Plant Health Agency, Addlestone, Surrey, United Kingdom
- Faculty of Health and Medical Science, University of Surrey, Guildford, Surrey, United Kingdom
| | | | - Alain Kohl
- MRC-University of Glasgow Centre for Virus Research, Glasgow, United Kingdom
| | - Roman Biek
- Institute of Biodiversity, Animal Health and Comparative Medicine - University of Glasgow, Glasgow, United Kingdom
- * E-mail: (JC); (RB)
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6
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Gaunt MW, Gubler DJ, Pettersson JHO, Kuno G, Wilder-Smith A, de Lamballerie X, Gould EA, Falconar AK. Recombination of B- and T-cell epitope-rich loci from Aedes- and Culex-borne flaviviruses shapes Zika virus epidemiology. Antiviral Res 2019; 174:104676. [PMID: 31837392 DOI: 10.1016/j.antiviral.2019.104676] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Revised: 12/06/2019] [Accepted: 12/08/2019] [Indexed: 02/07/2023]
Abstract
Sporadic human Zika virus (ZIKV) infections have been recorded in Africa and Asia since the 1950s. Major epidemics occurred only after ZIKV emerged in the Pacific islands and spread to the Americas. Specific biological determinants of the explosive epidemic nature of ZIKV have not been identified. Phylogenetic studies revealed incongruence in ZIKV placement in relation to Aedes-borne dengue viruses (DENV) and Culex-borne flaviviruses. We hypothesized that this incongruence reflects interspecies recombination resulting in ZIKV evasion of cross-protective T-cell immunity. We investigated ZIKV phylogenetic incongruence in relation to: DENV T-cell epitope maps experimentally identified ex vivo, published B-cell epitope loci, and CD8+ T-cell epitopes predicted in silico for mosquito-borne flaviviruses. Our findings demonstrate that the ZIKV proteome is a hybrid of Aedes-borne DENV proteins interspersed amongst Culex-borne flavivirus proteins derived through independent interspecies recombination events. These analyses infer that DENV-associated proteins in the ZIKV hybrid proteome generated immunodominant human B-cell responses, whereas ZIKV recombinant derived Culex-borne flavivirus-associated proteins generated immunodominant CD8+ and/or CD4+ T-cell responses. In silico CD8+ T-cell epitope ZIKV cross-reactive prediction analyses verified this observation. We propose that by acquiring cytotoxic T-cell epitope-rich regions from Culex-borne flaviviruses, ZIKV evaded DENV-generated T-cell immune cross-protection. Thus, Culex-borne flaviviruses, including West Nile virus and Japanese encephalitis virus, might induce cross-protective T-cell responses against ZIKV. This would explain why explosive ZIKV epidemics occurred in DENV-endemic regions of Micronesia, Polynesia and the Americas where Culex-borne flavivirus outbreaks are infrequent and why ZIKV did not cause major epidemics in Asia where Culex-borne flaviviruses are widespread.
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Affiliation(s)
- Michael W Gaunt
- London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK.
| | - Duane J Gubler
- Program in Emerging Infectious Diseases, Duke-NUS Medical School, 8 College Rd, 169857, Singapore
| | - John H-O Pettersson
- Department of Medical Biochemistry and Microbiology, Zoonosis Science Center, Uppsala University, Uppsala, Sweden; Marie Bashir Institute for Infectious Diseases and Biosecurity, Charles Perkins Centre, School of Life and Environmental Sciences and Sydney Medical School, University of Sydney, Sydney, New South Wales, 2006, Australia
| | - Goro Kuno
- 1648 Collindale Dr, Fort Collins, CO, 80525, USA
| | - Annelies Wilder-Smith
- London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK; Department of Public Health and Clinical Medicine, Epidemiology and Public Health, Umeå University, Umeå, Sweden; Heidelberg Institute of Global Health, University of Heidelberg, Germany
| | - Xavier de Lamballerie
- UMR "Unité des Virus Emergents", Aix-Marseille Université-IRD 190, Inserm, 1207-IHU Méditerranée Infection, Marseille, France
| | - Ernest A Gould
- UMR "Unité des Virus Emergents", Aix-Marseille Université-IRD 190, Inserm, 1207-IHU Méditerranée Infection, Marseille, France
| | - Andrew K Falconar
- Departmento de Medicina, Universidad del Norte, Barranquilla, Colombia
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Bentley K, Evans DJ. Mechanisms and consequences of positive-strand RNA virus recombination. J Gen Virol 2018; 99:1345-1356. [PMID: 30156526 DOI: 10.1099/jgv.0.001142] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Genetic recombination in positive-strand RNA viruses is a significant evolutionary mechanism that drives the creation of viral diversity by the formation of novel chimaeric genomes. The process and its consequences, for example the generation of viruses with novel phenotypes, has historically been studied by analysis of the end products. More recently, with an appreciation that there are both replicative and non-replicative mechanisms at work, and with new approaches and techniques to analyse intermediate products, the viral and cellular factors that influence the process are becoming understood. The major influence on replicative recombination is the fidelity of viral polymerase, although RNA structures and sequences may also have an impact. In replicative recombination the viral polymerase is necessary and sufficient, although roles for other viral or cellular proteins may exist. In contrast, non-replicative recombination appears to be mediated solely by cellular components. Despite these insights, the relative importance of replicative and non-replicative mechanisms is not clear. Using single-stranded positive-sense RNA viruses as exemplars, we review the current state of understanding of the processes and consequences of recombination.
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Affiliation(s)
- Kirsten Bentley
- Biomedical Sciences Research Complex and School of Biology, University of St Andrews, St Andrews, UK
| | - David J Evans
- Biomedical Sciences Research Complex and School of Biology, University of St Andrews, St Andrews, UK
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8
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Klitting R, Fischer C, Drexler JF, Gould EA, Roiz D, Paupy C, de Lamballerie X. What Does the Future Hold for Yellow Fever Virus? (II). Genes (Basel) 2018; 9:E425. [PMID: 30134625 PMCID: PMC6162518 DOI: 10.3390/genes9090425] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Revised: 08/13/2018] [Accepted: 08/16/2018] [Indexed: 02/06/2023] Open
Abstract
As revealed by the recent resurgence of yellow fever virus (YFV) activity in the tropical regions of Africa and South America, YFV control measures need urgent rethinking. Over the last decade, most reported outbreaks occurred in, or eventually reached, areas with low vaccination coverage but that are suitable for virus transmission, with an unprecedented risk of expansion to densely populated territories in Africa, South America and Asia. As reflected in the World Health Organization's initiative launched in 2017, it is high time to strengthen epidemiological surveillance to monitor accurately viral dissemination, and redefine vaccination recommendation areas. Vector-control and immunisation measures need to be adapted and vaccine manufacturing must be reconciled with an increasing demand. We will have to face more yellow fever (YF) cases in the upcoming years. Hence, improving disease management through the development of efficient treatments will prove most beneficial. Undoubtedly, these developments will require in-depth descriptions of YFV biology at molecular, physiological and ecological levels. This second section of a two-part review describes the current state of knowledge and gaps regarding the molecular biology of YFV, along with an overview of the tools that can be used to manage the disease at the individual, local and global levels.
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Affiliation(s)
- Raphaëlle Klitting
- Unité des Virus Émergents (UVE: Aix-Marseille Univ⁻IRD 190⁻Inserm 1207⁻IHU Méditerranée Infection), 13385 Marseille CEDEX 05, France.
| | - Carlo Fischer
- Charité-Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institute of Virology, 10117 Berlin, Germany.
- German Center for Infection Research (DZIF), 38124 Braunschweig, Germany.
| | - Jan F Drexler
- Charité-Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institute of Virology, 10117 Berlin, Germany.
- German Center for Infection Research (DZIF), 38124 Braunschweig, Germany.
- Martsinovsky Institute of Medical Parasitology, Tropical and Vector Borne Diseases, Sechenov University, 119991 Moscow, Russia.
| | - Ernest A Gould
- Unité des Virus Émergents (UVE: Aix-Marseille Univ⁻IRD 190⁻Inserm 1207⁻IHU Méditerranée Infection), 13385 Marseille CEDEX 05, France.
| | - David Roiz
- UMR Maladies Infectieuses et Vecteurs: Écologie, Génétique Évolution et Contrôle (MIVEGEC: IRD, CNRS, Univ. Montpellier), 34394 Montpellier, France.
| | - Christophe Paupy
- UMR Maladies Infectieuses et Vecteurs: Écologie, Génétique Évolution et Contrôle (MIVEGEC: IRD, CNRS, Univ. Montpellier), 34394 Montpellier, France.
| | - Xavier de Lamballerie
- Unité des Virus Émergents (UVE: Aix-Marseille Univ⁻IRD 190⁻Inserm 1207⁻IHU Méditerranée Infection), 13385 Marseille CEDEX 05, France.
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9
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Full-Genome Characterization and Genetic Evolution of West African Isolates of Bagaza Virus. Viruses 2018; 10:v10040193. [PMID: 29652824 PMCID: PMC5923487 DOI: 10.3390/v10040193] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Revised: 03/12/2018] [Accepted: 03/30/2018] [Indexed: 01/26/2023] Open
Abstract
Bagaza virus is a mosquito-borne flavivirus, first isolated in 1966 in Central African Republic. It has currently been identified in mosquito pools collected in the field in West and Central Africa. Emergence in wild birds in Europe and serological evidence in encephalitis patients in India raise questions on its genetic evolution and the diversity of isolates circulating in Africa. To better understand genetic diversity and evolution of Bagaza virus, we describe the full-genome characterization of 11 West African isolates, sampled from 1988 to 2014. Parameters such as genetic distances, N-glycosylation patterns, recombination events, selective pressures, and its codon adaptation to human genes are assessed. Our study is noteworthy for the observation of N-glycosylation and recombination in Bagaza virus and provides insight into its Indian origin from the 13th century. Interestingly, evidence of Bagaza virus codon adaptation to human house-keeping genes is also observed to be higher than those of other flaviviruses well known in human infections. Genetic variations on genome of West African Bagaza virus could play an important role in generating diversity and may promote Bagaza virus adaptation to other vertebrates and become an important threat in human health.
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10
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Sironi M, Forni D, Clerici M, Cagliani R. Nonstructural Proteins Are Preferential Positive Selection Targets in Zika Virus and Related Flaviviruses. PLoS Negl Trop Dis 2016; 10:e0004978. [PMID: 27588756 PMCID: PMC5010288 DOI: 10.1371/journal.pntd.0004978] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Accepted: 08/14/2016] [Indexed: 11/18/2022] Open
Abstract
The Flavivirus genus comprises several human pathogens such as dengue virus (DENV), Japanese encephalitis virus (JEV), and Zika virus (ZIKV). Although ZIKV usually causes mild symptoms, growing evidence is linking it to congenital birth defects and to increased risk of Guillain-Barré syndrome. ZIKV encodes a polyprotein that is processed to produce three structural and seven nonstructural (NS) proteins. We investigated the evolution of the viral polyprotein in ZIKV and in related flaviviruses (DENV, Spondweni virus, and Kedougou virus). After accounting for saturation issues, alignment uncertainties, and recombination, we found evidence of episodic positive selection on the branch that separates DENV from the other flaviviruses. NS1 emerged as the major selection target, and selected sites were located in immune epitopes or in functionally important protein regions. Three of these sites are located in an NS1 region that interacts with structural proteins and is essential for virion biogenesis. Analysis of the more recent evolutionary history of ZIKV lineages indicated that positive selection acted on NS5 and NS4B, this latter representing the preferential target. All selected sites were located in the N-terminal portion of NS4B, which inhibits interferon response. One of the positively selected sites (26M/I/T/V) in ZIKV also represents a selection target in sylvatic DENV2 isolates, and a nearby residue evolves adaptively in JEV. Two additional positively selected sites are within a protein region that interacts with host (e.g. STING) and viral (i.e. NS1, NS4A) proteins. Notably, mutations in the NS4B region of other flaviviruses modulate neurovirulence and/or neuroinvasiveness. These results suggest that the positively selected sites we identified modulate viral replication and contribute to immune evasion. These sites should be prioritized in future experimental studies. However, analyses herein detected no selective events associated to the spread of the Asian/American ZIKV lineage.
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Affiliation(s)
- Manuela Sironi
- Scientific Institute IRCCS E. MEDEA, Bioinformatics, Bosisio Parini, Italy
| | - Diego Forni
- Scientific Institute IRCCS E. MEDEA, Bioinformatics, Bosisio Parini, Italy
| | - Mario Clerici
- Department of Physiopathology and Transplantation, University of Milan, Milan, Italy
- Don C. Gnocchi Foundation ONLUS, IRCCS, Milan, Italy
| | - Rachele Cagliani
- Scientific Institute IRCCS E. MEDEA, Bioinformatics, Bosisio Parini, Italy
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Wu H, Rao P, Jiang Y, Opriessnig T, Yang Z. A sensitive multiplex real-time PCR panel for rapid diagnosis of viruses associated with porcine respiratory and reproductive disorders. Mol Cell Probes 2014; 28:264-70. [DOI: 10.1016/j.mcp.2014.07.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2014] [Revised: 06/19/2014] [Accepted: 07/11/2014] [Indexed: 10/25/2022]
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Comparison of genotypes I and III in Japanese encephalitis virus reveals distinct differences in their genetic and host diversity. J Virol 2014; 88:11469-79. [PMID: 25056890 DOI: 10.1128/jvi.02050-14] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
UNLABELLED Japanese encephalitis (JE) is an arthropod-borne disease associated with the majority of viral encephalitis cases in the Asia-Pacific region. The causative agent, Japanese encephalitis virus (JEV), has been phylogenetically divided into five genotypes. Recent surveillance data indicate that genotype I (GI) is gradually replacing genotype III (GIII) as the dominant genotype. To investigate the mechanism behind the genotype shift and the potential consequences in terms of vaccine efficacy, human cases, and virus dissemination, we collected (i) all full-length and partial JEV molecular sequences and (ii) associated genotype and host information comprising a data set of 873 sequences. We then examined differences between the two genotypes at the genetic and epidemiological level by investigating amino acid mutations, positive selection, and host range. We found that although GI is dominant, it has fewer sites predicted to be under positive selection, a narrower host range, and significantly fewer human isolates. For the E protein, the sites under positive selection define a haplotype set for each genotype that shows striking differences in their composition and diversity, with GIII showing significantly more variety than GI. Our results suggest that GI has displaced GIII by achieving a replication cycle that is more efficient but is also more restricted in its host range. IMPORTANCE Japanese encephalitis is an arthropod-borne disease associated with the majority of viral encephalitis cases in the Asia-Pacific region. The causative agent, Japanese encephalitis virus (JEV), has been divided into five genotypes based on sequence similarity. Recent data indicate that genotype I (GI) is gradually replacing genotype III (GIII) as the dominant genotype. Understanding the reasons behind this shift and the potential consequences in terms of vaccine efficacy, human cases, and virus dissemination is important for controlling the spread of the virus and reducing human fatalities. We collected all available full-length and partial JEV molecular sequences and associated genotype and host information. We then examined differences between the two genotypes at the genetic and epidemiological levels by investigating amino acid mutations, positive selection, and host range. Our results suggest that GI has displaced GIII by achieving a replication cycle that is more efficient but more restricted in host range.
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Chiang WW, Chuang CK, Chao M, Chen WJ. Cell type-dependent RNA recombination frequency in the Japanese encephalitis virus. BIOMED RESEARCH INTERNATIONAL 2014; 2014:471323. [PMID: 25165704 PMCID: PMC4140105 DOI: 10.1155/2014/471323] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/10/2014] [Accepted: 07/02/2014] [Indexed: 11/17/2022]
Abstract
Japanese encephalitis virus (JEV) is one of approximately 70 flaviviruses, frequently causing symptoms involving the central nervous system. Mutations of its genomic RNA frequently occur during viral replication, which is believed to be a force contributing to viral evolution. Nevertheless, accumulating evidences show that some JEV strains may have actually arisen from RNA recombination between genetically different populations of the virus. We have demonstrated that RNA recombination in JEV occurs unequally in different cell types. In the present study, viral RNA fragments transfected into as well as viral RNAs synthesized in mosquito cells were shown not to be stable, especially in the early phase of infection possibly via cleavage by exoribonuclease. Such cleaved small RNA fragments may be further degraded through an RNA interference pathway triggered by viral double-stranded RNA during replication in mosquito cells, resulting in a lower frequency of RNA recombination in mosquito cells compared to that which occurs in mammalian cells. In fact, adjustment of viral RNA to an appropriately lower level in mosquito cells prevents overgrowth of the virus and is beneficial for cells to survive the infection. Our findings may also account for the slower evolution of arboviruses as reported previously.
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Affiliation(s)
- Wei-Wei Chiang
- Division of Microbiology, Graduate Institute of Biomedical Sciences, Chang Gung University, Kwei-San, Tao-Yuan 33332, Taiwan
| | - Ching-Kai Chuang
- Division of Microbiology, Graduate Institute of Biomedical Sciences, Chang Gung University, Kwei-San, Tao-Yuan 33332, Taiwan
- Department of Plant Pathology, University of Kentucky, Lexington, KY 40546-0312, USA
| | - Mei Chao
- Division of Microbiology, Graduate Institute of Biomedical Sciences, Chang Gung University, Kwei-San, Tao-Yuan 33332, Taiwan
- Department of Microbiology and Immunology, Chang Gung University, Kwei-San, Tao-Yuan 33332, Taiwan
| | - Wei-June Chen
- Division of Microbiology, Graduate Institute of Biomedical Sciences, Chang Gung University, Kwei-San, Tao-Yuan 33332, Taiwan
- Department of Public Health and Parasitology, Chang Gung University, Kwei-San, Tao-Yuan 33332, Taiwan
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Zhang H, Zhang Y, Hamoudi R, Yan G, Chen X, Zhou Y. Spatiotemporal characterizations of dengue virus in mainland China: insights into the whole genome from 1978 to 2011. PLoS One 2014; 9:e87630. [PMID: 24551062 PMCID: PMC3925084 DOI: 10.1371/journal.pone.0087630] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2013] [Accepted: 12/25/2013] [Indexed: 12/19/2022] Open
Abstract
Temporal-Spatial of dengue virus (DENV) analyses have been performed in previous epidemiological studies in mainland China, but few studies have examined the whole genome of the DENV. Herein, 40 whole genome sequences of DENVs isolated from mainland China were downloaded from GenBank. Phylogenetic analyses and evolutionary distances of the dengue serotypes 1 and 2 were calculated using 14 maximum likelihood trees created from individual genes and whole genome. Amino acid variations were also analyzed in the 40 sequences that included dengue serotypes 1, 2, 3 and 4, and they were grouped according to temporal and spatial differences. The results showed that none of the phylogenetic trees created from each individual gene were similar to the trees created using the complete genome and the evolutionary distances were variable with each individual gene. The number of amino acid variations was significantly different (p = 0.015) between DENV-1 and DENV-2 after 2001; seven mutations, the N290D, L402F and A473T mutations in the E gene region and the R101K, G105R, D340E and L349M mutations in the NS1 region of DENV-1, had significant substitutions, compared to the amino acids of DENV-2. Based on the spatial distribution using Guangzhou, including Foshan, as the indigenous area and the other regions as expanding areas, significant differences in the number of amino acid variations in the NS3 (p = 0.03) and NS1 (p = 0.024) regions and the NS2B (p = 0.016) and NS3 (p = 0.042) regions were found in DENV-1 and DENV-2. Recombination analysis showed no inter-serotype recombination events between the DENV-1 and DENV-2, while six and seven breakpoints were found in DENV-1 and DENV-2. Conclusively, the individual genes might not be suitable to analyze the evolution and selection pressure isolated in mainland China; the mutations in the amino acid residues in the E, NS1 and NS3 regions may play important roles in DENV-1 and DENV-2 epidemics.
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Affiliation(s)
- Hao Zhang
- Department of Infectious Diseases, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong Province, China
- Key Laboratory of Prevention and Control for Emerging Infectious Diseases of Guangdong Province, School of Public Health and Tropical Medicine, Southern Medical Guangzhou, Guangdong Province, China
| | - Yanru Zhang
- Department of Infectious Diseases, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong Province, China
| | - Rifat Hamoudi
- Department of Pathology, Rockefeller Building, University College London, London, United Kingdom
- UCL Cancer Institute, Paul O Gorman Building, University College London, London, United Kingdom
| | - Guiyun Yan
- Program in Public Health, University of California Irvine, Irvine, California, United States of America
| | - Xiaoguang Chen
- Key Laboratory of Prevention and Control for Emerging Infectious Diseases of Guangdong Province, School of Public Health and Tropical Medicine, Southern Medical Guangzhou, Guangdong Province, China
- * E-mail: (XGC); (YPZ)
| | - Yuanping Zhou
- Department of Infectious Diseases, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong Province, China
- * E-mail: (XGC); (YPZ)
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15
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Liu WJ, Zhu M, Pei JJ, Dong XY, Liu W, Zhao MQ, Wang JY, Gou HC, Luo YW, Chen JD. Molecular phylogenetic and positive selection analysis of Japanese encephalitis virus strains isolated from pigs in China. Virus Res 2013; 178:547-52. [PMID: 24045128 DOI: 10.1016/j.virusres.2013.09.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2013] [Revised: 08/02/2013] [Accepted: 09/02/2013] [Indexed: 11/19/2022]
Abstract
Japanese encephalitis virus (JEV) is one of the most important virus which causes encephalitis. This disease is most prevalent in the south, southeast and the east region of Asia. In this study, two JEV strains, named JEV/SW/GD/01/2009 and JEV/SW/GZ/09/2004, were isolated from aborted fetuses and seminal fluid of pigs in China. To determine the characteristic of these virus isolates, the virulence of two newly JEV isolates was investigated, the result evidenced that the JEV/SW/GD/01/2009 did not kill mice, while the JEV/SW/GZ/09/2004 displayed neurovirulence with 0.925log10 p.f.u./LD50. Additionally, the full genome sequences of JEV were determined and compared with other known JEV strains. Results demonstrated that the genome of two JEV isolates was 10,976 nucleotides (nt) in length. As compared to the Chinese vaccine strain SA14-14-2, the JEV/SW/GD/01/2009 and the JEV/SW/GZ/09/2004 showed 99.7% and 97.5% identity at the nucleotide level, 99.6% and 96.7% identity at the amino acid level, respectively. Phylogenetic analysis, based on the full-length genome revealed that two JEV isolates were all clustered into genotype III compared to the reference strains. Furthermore, selection analyses revealed that dominant selective pressure acting on the JEV genome was purifying selection. Four sites under positive selection were identified: codon 521 (amino acid E-227), 2296 (amino acid NS4b-24), 3048 (amino acid NS5-521) and 3055 (amino acid NS5-528). Amino acid E-227 was proved to be related to neurovirulence. Taken together, the molecular epidemiology and functional of positively selected amino acid sites of two newly JEV isolates were fully understood, which might be helpful to predict possible changes in virulence.
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MESH Headings
- Aborted Fetus/virology
- Animals
- China
- Cluster Analysis
- Disease Models, Animal
- Encephalitis Virus, Japanese/classification
- Encephalitis Virus, Japanese/genetics
- Encephalitis Virus, Japanese/isolation & purification
- Encephalitis Virus, Japanese/pathogenicity
- Encephalitis, Japanese/virology
- Genotype
- Mice
- Molecular Sequence Data
- Mutation, Missense
- Phylogeny
- RNA, Viral/genetics
- Selection, Genetic
- Semen/virology
- Sequence Analysis, DNA
- Serial Passage
- Survival Analysis
- Swine
- Swine Diseases/virology
- Virulence
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Affiliation(s)
- Wen-Jun Liu
- College of Veterinary Medicine, South China Agricultural University, No. 483, Wushan Road, Tianhe District, Guangzhou 510640, PR China
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