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Rosales-Munar A, Alvarez-Diaz DA, Laiton-Donato K, Peláez-Carvajal D, Usme-Ciro JA. Efficient Method for Molecular Characterization of the 5' and 3' Ends of the Dengue Virus Genome. Viruses 2020; 12:v12050496. [PMID: 32365696 PMCID: PMC7290889 DOI: 10.3390/v12050496] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Revised: 03/27/2020] [Accepted: 04/01/2020] [Indexed: 11/16/2022] Open
Abstract
Dengue is a mosquito-borne disease that is of major importance in public health. Although it has been extensively studied at the molecular level, sequencing of the 5′ and 3′ ends of the untranslated regions (UTR) commonly requires specific approaches for completion and corroboration. The present study aimed to characterize the 5′ and 3′ ends of dengue virus types 1 to 4. The 5′ and 3′ ends of twenty-nine dengue virus isolates from acute infections were amplified through a modified protocol of the rapid amplification cDNA ends approach. For the 5′ end cDNA synthesis, specific anti-sense primers for each serotype were used, followed by polyadenylation of the cDNA using a terminal transferase and subsequent PCR amplification with oligo(dT) and internal specific reverse primer. At the 3′ end of the positive-sense viral RNA, an adenine tail was directly synthetized using an Escherichia coli poly(A) polymerase, allowing subsequent hybridization of the oligo(dT) during cDNA synthesis. The incorporation of the poly(A) tail at the 5′ and 3′ ends of the dengue virus cDNA and RNA, respectively, allowed for successful primer hybridization, PCR amplification and direct sequencing. This approach can be used for completing dengue virus genomes obtained through direct and next-generation sequencing methods.
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Affiliation(s)
- Alicia Rosales-Munar
- Sequencing and Genomics Unit, Virology Laboratory, Dirección de Redes en Salud Pública, Instituto Nacional de Salud, Bogotá 111321, Colombia; (A.R.-M.); (D.A.A.-D.); (K.L.-D.); (D.P.-C.)
| | - Diego Alejandro Alvarez-Diaz
- Sequencing and Genomics Unit, Virology Laboratory, Dirección de Redes en Salud Pública, Instituto Nacional de Salud, Bogotá 111321, Colombia; (A.R.-M.); (D.A.A.-D.); (K.L.-D.); (D.P.-C.)
| | - Katherine Laiton-Donato
- Sequencing and Genomics Unit, Virology Laboratory, Dirección de Redes en Salud Pública, Instituto Nacional de Salud, Bogotá 111321, Colombia; (A.R.-M.); (D.A.A.-D.); (K.L.-D.); (D.P.-C.)
| | - Dioselina Peláez-Carvajal
- Sequencing and Genomics Unit, Virology Laboratory, Dirección de Redes en Salud Pública, Instituto Nacional de Salud, Bogotá 111321, Colombia; (A.R.-M.); (D.A.A.-D.); (K.L.-D.); (D.P.-C.)
| | - Jose A. Usme-Ciro
- Sequencing and Genomics Unit, Virology Laboratory, Dirección de Redes en Salud Pública, Instituto Nacional de Salud, Bogotá 111321, Colombia; (A.R.-M.); (D.A.A.-D.); (K.L.-D.); (D.P.-C.)
- Centro de Investigación en Salud para el Trópico-CIST, Facultad de Medicina, Universidad Cooperativa de Colombia, Santa Marta 470003, Colombia
- Correspondence: ; Tel.: +57-314-628-9435
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Short Direct Repeats in the 3' Untranslated Region Are Involved in Subgenomic Flaviviral RNA Production. J Virol 2020; 94:JVI.01175-19. [PMID: 31896596 DOI: 10.1128/jvi.01175-19] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Accepted: 12/18/2019] [Indexed: 11/20/2022] Open
Abstract
Mosquito-borne flaviviruses consist of a positive-sense genome RNA flanked by the untranslated regions (UTRs). There is a panel of highly complex RNA structures in the UTRs with critical functions. For instance, Xrn1-resistant RNAs (xrRNAs) halt Xrn1 digestion, leading to the production of subgenomic flaviviral RNA (sfRNA). Conserved short direct repeats (DRs), also known as conserved sequences (CS) and repeated conserved sequences (RCS), have been identified as being among the RNA elements locating downstream of xrRNAs, but their biological function remains unknown. In this study, we revealed that the specific DRs are involved in the production of specific sfRNAs in both mammalian and mosquito cells. Biochemical assays and structural remodeling demonstrate that the base pairings in the stem of these DRs control sfRNA formation by maintaining the binding affinity of the corresponding xrRNAs to Xrn1. On the basis of these findings, we propose that DRs functions like a bracket holding the Xrn1-xrRNA complex for sfRNA formation.IMPORTANCE Flaviviruses include many important human pathogens. The production of subgenomic flaviviral RNAs (sfRNAs) is important for viral pathogenicity as a common feature of flaviviruses. sfRNAs are formed through the incomplete degradation of viral genomic RNA by the cytoplasmic 5'-3' exoribonuclease Xrn1 halted at the Xrn1-resistant RNA (xrRNA) structures within the 3'-UTR. The 3'-UTRs of the flavivirus genome also contain distinct short direct repeats (DRs), such as RCS3, CS3, RCS2, and CS2. However, the biological functions of these ancient primary DR sequences remain largely unknown. Here, we found that DR sequences are involved in sfRNA formation and viral virulence and provide novel targets for the rational design of live attenuated flavivirus vaccine.
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Domingo E, de Ávila AI, Gallego I, Sheldon J, Perales C. Viral fitness: history and relevance for viral pathogenesis and antiviral interventions. Pathog Dis 2020; 77:5454742. [PMID: 30980658 DOI: 10.1093/femspd/ftz021] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Accepted: 04/06/2019] [Indexed: 02/06/2023] Open
Abstract
The quasispecies dynamics of viral populations (continuous generation of variant genomes and competition among them) has as one of its frequent consequences variations in overall multiplication capacity, a major component of viral fitness. This parameter has multiple implications for viral pathogenesis and viral disease control, some of them unveiled thanks to deep sequencing of viral populations. Darwinian fitness is an old concept whose quantification dates back to the early developments of population genetics. It was later applied to viruses (mainly to RNA viruses) to quantify relative multiplication capacities of individual mutant clones or complex populations. The present article reviews the fitness concept and its relevance for the understanding of the adaptive dynamics of viruses in constant and changing environments. Many studies have addressed the fitness cost of escape mutations (to antibodies, cytotoxic T cells or inhibitors) as an influence on the efficacy of antiviral interventions. Here, we summarize the evidence that the basal fitness level can be a determinant of inhibitor resistance.
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Affiliation(s)
- Esteban Domingo
- Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Consejo Superior de Investigaciones Científicas (CSIC), C/ Nicolás Cabrera 1, Campus de Cantoblanco, Madrid 28049, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd) del Instituto de Salud Carlos III, Madrid 28029, Spain
| | - Ana I de Ávila
- Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Consejo Superior de Investigaciones Científicas (CSIC), C/ Nicolás Cabrera 1, Campus de Cantoblanco, Madrid 28049, Spain
| | - Isabel Gallego
- Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Consejo Superior de Investigaciones Científicas (CSIC), C/ Nicolás Cabrera 1, Campus de Cantoblanco, Madrid 28049, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd) del Instituto de Salud Carlos III, Madrid 28029, Spain
| | - Julie Sheldon
- Institute of Experimental Virology, Twincore, Centre for Experimental and Clinical Infection Research, A Joint Venture Between Medical School Hannover (MHH) and Helmholtz Centre for Infection Research (HZI), D-30625, Hannover, Germany
| | - Celia Perales
- Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Consejo Superior de Investigaciones Científicas (CSIC), C/ Nicolás Cabrera 1, Campus de Cantoblanco, Madrid 28049, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd) del Instituto de Salud Carlos III, Madrid 28029, Spain.,Department of Clinical Microbiology, IIS-Fundación Jiménez Díaz, UAM. Av. Reyes Católicos 2, Madrid 28040, Spain
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54
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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: 1.6] [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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An RNA Thermometer Activity of the West Nile Virus Genomic 3'-Terminal Stem-Loop Element Modulates Viral Replication Efficiency during Host Switching. Viruses 2020; 12:v12010104. [PMID: 31952291 PMCID: PMC7019923 DOI: 10.3390/v12010104] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Revised: 12/20/2019] [Accepted: 01/12/2020] [Indexed: 02/07/2023] Open
Abstract
The 3′-terminal stem-loop (3′SL) of the RNA genome of the flavivirus West Nile (WNV) harbors, in its stem, one of the sequence elements that are required for genome cyclization. As cyclization is a prerequisite for the initiation of viral replication, the 3′SL was proposed to act as a replication silencer. The lower part of the 3′SL is metastable and confers a structural flexibility that may regulate the switch from the linear to the circular conformation of the viral RNA. In the human system, we previously demonstrated that a cellular RNA-binding protein, AUF1 p45, destabilizes the 3′SL, exposes the cyclization sequence, and thus promotes flaviviral genome cyclization and RNA replication. By investigating mutant RNAs with increased 3′SL stabilities, we showed the specific conformation of the metastable element to be a critical determinant of the helix-destabilizing RNA chaperone activity of AUF1 p45 and of the precision and efficiency of the AUF1 p45-supported initiation of RNA replication. Studies of stability-increasing mutant WNV replicons in human and mosquito cells revealed that the cultivation temperature considerably affected the replication efficiencies of the viral RNA variants and demonstrated the silencing effect of the 3′SL to be temperature dependent. Furthermore, we identified and characterized mosquito proteins displaying similar activities as AUF1 p45. However, as the RNA remodeling activities of the mosquito proteins were found to be considerably lower than those of the human protein, a potential cell protein-mediated destabilization of the 3′SL was suggested to be less efficient in mosquito cells. In summary, our data support a model in which the 3′SL acts as an RNA thermometer that modulates flavivirus replication during host switching.
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56
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Abstract
Viral population numbers are extremely large compared with those of their host species. Population bottlenecks are frequent during the life cycle of viruses and can reduce viral populations transiently to very few individuals. Viruses have to confront several types of constraints that can be divided into basal, cell-dependent, and organism-dependent constraints. Viruses overcome them exploiting a number of molecular mechanisms, with an important contribution of population numbers and genome variation. The adaptive potential of viruses is reflected in modifications of cell tropism and host range, escape to components of the host immune response, and capacity to alternate among different host species, among other phenotypic changes. Despite a fitness cost of most mutations required to overcome a selective constraint, viruses can find evolutionary pathways that ensure their survival in equilibrium with their hosts.
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57
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Sanford TJ, Mears HV, Fajardo T, Locker N, Sweeney TR. Circularization of flavivirus genomic RNA inhibits de novo translation initiation. Nucleic Acids Res 2019; 47:9789-9802. [PMID: 31392996 PMCID: PMC6765113 DOI: 10.1093/nar/gkz686] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Revised: 07/22/2019] [Accepted: 07/26/2019] [Indexed: 12/20/2022] Open
Abstract
Members of the Flaviviridae family, including dengue virus (DENV) and yellow fever virus, cause serious disease in humans, whilst maternal infection with Zika virus (ZIKV) can induce microcephaly in newborns. Following infection, flaviviral RNA genomes are translated to produce the viral replication machinery but must then serve as a template for the transcription of new genomes. However, the ribosome and viral polymerase proceed in opposite directions along the RNA, risking collisions and abortive replication. Whilst generally linear, flavivirus genomes can adopt a circular conformation facilitated by long-range RNA–RNA interactions, shown to be essential for replication. Using an in vitro reconstitution approach, we demonstrate that circularization inhibits de novo translation initiation on ZIKV and DENV RNA, whilst the linear conformation is translation-competent. Our results provide a mechanism to clear the viral RNA of ribosomes in order to promote efficient replication and, therefore, define opposing roles for linear and circular conformations of the flavivirus genome.
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Affiliation(s)
- Thomas J Sanford
- Division of Virology, Department of Pathology, University of Cambridge, Addenbrooke's Hospital, Hills Road, Cambridge, CB2 0QQ, UK
| | - Harriet V Mears
- Division of Virology, Department of Pathology, University of Cambridge, Addenbrooke's Hospital, Hills Road, Cambridge, CB2 0QQ, UK
| | - Teodoro Fajardo
- Division of Virology, Department of Pathology, University of Cambridge, Addenbrooke's Hospital, Hills Road, Cambridge, CB2 0QQ, UK
| | - Nicolas Locker
- Faculty of Health and Medical Sciences, School of Biosciences and Medicine, University of Surrey, Guildford, GU2 7HX, UK
| | - Trevor R Sweeney
- Division of Virology, Department of Pathology, University of Cambridge, Addenbrooke's Hospital, Hills Road, Cambridge, CB2 0QQ, UK
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58
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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: 21] [Impact Index Per Article: 3.5] [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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59
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Zhang Y, Zhang Y, Liu Z, Cheng M, Ma J, Wang Y, Qin C, Fang X. Long non-coding subgenomic flavivirus RNAs have extended 3D structures and are flexible in solution. EMBO Rep 2019; 20:e47016. [PMID: 31502753 PMCID: PMC6832101 DOI: 10.15252/embr.201847016] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Revised: 08/14/2019] [Accepted: 08/21/2019] [Indexed: 01/05/2023] Open
Abstract
Most mosquito-borne flaviviruses, including Zika virus (ZIKV), Dengue virus (DENV), and West Nile virus (WNV), produce long non-coding subgenomic RNAs (sfRNAs) in infected cells that link to pathogenicity and immune evasion. Until now, the structural characterization of these lncRNAs remains limited. Here, we studied the 3D structures of individual and combined subdomains of sfRNAs, and visualized the accessible 3D conformational spaces of complete sfRNAs from DENV2, ZIKV, and WNV by small angle X-ray scattering (SAXS) and computational modeling. The individual xrRNA1s and xrRNA2s adopt similar structures in solution as the crystal structure of ZIKV xrRNA1, and all xrRNA1-2s form compact structures with reduced flexibility. While the DB12 of DENV2 is extended, the DB12s of ZIKV and WNV are compact due to the formation of intertwined double pseudoknots. All 3' stem-loops (3'SLs) share similar rod-like structures. Complete sfRNAs are extended and sample a large conformational space in solution. Our work not only provides structural insight into the function of flavivirus sfRNAs, but also highlights strategies of visualizing other lncRNAs in solution by SAXS and computational methods.
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Affiliation(s)
- Yupeng Zhang
- Beijing Advanced Innovation Center for Structural BiologySchool of Life SciencesTsinghua UniversityBeijingChina
| | - Yikan Zhang
- Beijing Advanced Innovation Center for Structural BiologySchool of Life SciencesTsinghua UniversityBeijingChina
| | - Zhong‐Yu Liu
- State Key Laboratory of Pathogen and BiosecurityBeijing Institute of Microbiology and EpidemiologyBeijingChina
- Guangzhou Eighth People's HospitalGuangzhou Medical UniversityGuangzhouChina
- School of Medicine (Shenzhen)Sun Yat‐sen UniversityGuangzhouChina
| | - Meng‐Li Cheng
- State Key Laboratory of Pathogen and BiosecurityBeijing Institute of Microbiology and EpidemiologyBeijingChina
| | - Junfeng Ma
- Beijing Advanced Innovation Center for Structural BiologySchool of Life SciencesTsinghua UniversityBeijingChina
| | - Yan Wang
- Beijing Advanced Innovation Center for Structural BiologySchool of Life SciencesTsinghua UniversityBeijingChina
| | - Cheng‐Feng Qin
- State Key Laboratory of Pathogen and BiosecurityBeijing Institute of Microbiology and EpidemiologyBeijingChina
| | - Xianyang Fang
- Beijing Advanced Innovation Center for Structural BiologySchool of Life SciencesTsinghua UniversityBeijingChina
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60
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Marshall JM, Raban RR, Kandul NP, Edula JR, León TM, Akbari OS. Winning the Tug-of-War Between Effector Gene Design and Pathogen Evolution in Vector Population Replacement Strategies. Front Genet 2019; 10:1072. [PMID: 31737050 PMCID: PMC6831721 DOI: 10.3389/fgene.2019.01072] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Accepted: 10/07/2019] [Indexed: 12/19/2022] Open
Abstract
While efforts to control malaria with available tools have stagnated, and arbovirus outbreaks persist around the globe, the advent of clustered regularly interspaced short palindromic repeat (CRISPR)-based gene editing has provided exciting new opportunities for genetics-based strategies to control these diseases. In one such strategy, called "population replacement", mosquitoes, and other disease vectors are engineered with effector genes that render them unable to transmit pathogens. These effector genes can be linked to "gene drive" systems that can bias inheritance in their favor, providing novel opportunities to replace disease-susceptible vector populations with disease-refractory ones over the course of several generations. While promising for the control of vector-borne diseases on a wide scale, this sets up an evolutionary tug-of-war between the introduced effector genes and the pathogen. Here, we review the disease-refractory genes designed to date to target Plasmodium falciparum malaria transmitted by Anopheles gambiae, and arboviruses transmitted by Aedes aegypti, including dengue serotypes 2 and 3, chikungunya, and Zika viruses. We discuss resistance concerns for these effector genes, and genetic approaches to prevent parasite and viral escape variants. One general approach is to increase the evolutionary hurdle required for the pathogen to evolve resistance by attacking it at multiple sites in its genome and/or multiple stages of development. Another is to reduce the size of the pathogen population by other means, such as with vector control and antimalarial drugs. We discuss lessons learned from the evolution of resistance to antimalarial and antiviral drugs and implications for the management of resistance after its emergence. Finally, we discuss the target product profile for population replacement strategies for vector-borne disease control. This differs between early phase field trials and wide-scale disease control. In the latter case, the demands on effector gene efficacy are great; however, with new possibilities ushered in by CRISPR-based gene editing, and when combined with surveillance, monitoring, and rapid management of pathogen resistance, the odds are increasingly favoring effector genes in the upcoming evolutionary tug-of-war.
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Affiliation(s)
- John M. Marshall
- Division of Epidemiology and Biostatistics, School of Public Health, University of California, Berkeley, CA, United States
- Innovative Genomics Institute, Berkeley, CA, United States
| | - Robyn R. Raban
- Section of Cell and Developmental Biology, University of California, San Diego, CA, United States
| | - Nikolay P. Kandul
- Section of Cell and Developmental Biology, University of California, San Diego, CA, United States
| | - Jyotheeswara R. Edula
- Section of Cell and Developmental Biology, University of California, San Diego, CA, United States
| | - Tomás M. León
- Division of Epidemiology and Biostatistics, School of Public Health, University of California, Berkeley, CA, United States
| | - Omar S. Akbari
- Section of Cell and Developmental Biology, University of California, San Diego, CA, United States
- Tata Institute for Genetics and Society, University of California, San Diego, CA, United States
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61
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Göertz GP, van Bree JWM, Hiralal A, Fernhout BM, Steffens C, Boeren S, Visser TM, Vogels CBF, Abbo SR, Fros JJ, Koenraadt CJM, van Oers MM, Pijlman GP. Subgenomic flavivirus RNA binds the mosquito DEAD/H-box helicase ME31B and determines Zika virus transmission by Aedes aegypti. Proc Natl Acad Sci U S A 2019; 116:19136-19144. [PMID: 31488709 PMCID: PMC6754610 DOI: 10.1073/pnas.1905617116] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Zika virus (ZIKV) is an arthropod-borne flavivirus predominantly transmitted by Aedes aegypti mosquitoes and poses a global human health threat. All flaviviruses, including those that exclusively replicate in mosquitoes, produce a highly abundant, noncoding subgenomic flavivirus RNA (sfRNA) in infected cells, which implies an important function of sfRNA during mosquito infection. Currently, the role of sfRNA in flavivirus transmission by mosquitoes is not well understood. Here, we demonstrate that an sfRNA-deficient ZIKV (ZIKVΔSF1) replicates similar to wild-type ZIKV in mosquito cell culture but is severely attenuated in transmission by Ae. aegypti after an infectious blood meal, with 5% saliva-positive mosquitoes for ZIKVΔSF1 vs. 31% for ZIKV. Furthermore, viral titers in the mosquito saliva were lower for ZIKVΔSF1 as compared to ZIKV. Comparison of mosquito infection via infectious blood meals and intrathoracic injections showed that sfRNA is important for ZIKV to overcome the mosquito midgut barrier and to promote virus accumulation in the saliva. Next-generation sequencing of infected mosquitoes showed that viral small-interfering RNAs were elevated upon ZIKVΔSF1 as compared to ZIKV infection. RNA-affinity purification followed by mass spectrometry analysis uncovered that sfRNA specifically interacts with a specific set of Ae. aegypti proteins that are normally associated with RNA turnover and protein translation. The DEAD/H-box helicase ME31B showed the highest affinity for sfRNA and displayed antiviral activity against ZIKV in Ae. aegypti cells. Based on these results, we present a mechanistic model in which sfRNA sequesters ME31B to promote flavivirus replication and virion production to facilitate transmission by mosquitoes.
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Affiliation(s)
- Giel P Göertz
- Laboratory of Virology, Wageningen University & Research, 6708 PB, Wageningen, The Netherlands
| | - Joyce W M van Bree
- Laboratory of Virology, Wageningen University & Research, 6708 PB, Wageningen, The Netherlands
| | - Anwar Hiralal
- Laboratory of Virology, Wageningen University & Research, 6708 PB, Wageningen, The Netherlands
| | - Bas M Fernhout
- Laboratory of Virology, Wageningen University & Research, 6708 PB, Wageningen, The Netherlands
| | - Carmen Steffens
- Laboratory of Virology, Wageningen University & Research, 6708 PB, Wageningen, The Netherlands
| | - Sjef Boeren
- Laboratory of Biochemistry, Wageningen University & Research, 6708 WE, Wageningen, The Netherlands
| | - Tessa M Visser
- Laboratory of Entomology, Wageningen University & Research, 6708 PB, Wageningen, The Netherlands
| | - Chantal B F Vogels
- Laboratory of Entomology, Wageningen University & Research, 6708 PB, Wageningen, The Netherlands
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT 06510
| | - Sandra R Abbo
- Laboratory of Virology, Wageningen University & Research, 6708 PB, Wageningen, The Netherlands
| | - Jelke J Fros
- Laboratory of Virology, Wageningen University & Research, 6708 PB, Wageningen, The Netherlands
| | | | - Monique M van Oers
- Laboratory of Virology, Wageningen University & Research, 6708 PB, Wageningen, The Netherlands
| | - Gorben P Pijlman
- Laboratory of Virology, Wageningen University & Research, 6708 PB, Wageningen, The Netherlands;
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62
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Finol E, Ooi EE. Evolution of Subgenomic RNA Shapes Dengue Virus Adaptation and Epidemiological Fitness. iScience 2019; 16:94-105. [PMID: 31154208 PMCID: PMC6545344 DOI: 10.1016/j.isci.2019.05.019] [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: 03/26/2018] [Revised: 02/02/2019] [Accepted: 05/13/2019] [Indexed: 01/07/2023] Open
Abstract
Changes in dengue virus (DENV) genome affect viral fitness both clinically and epidemiologically. Even in the 3′ untranslated region (3′ UTR), mutations could affect subgenomic flaviviral RNA (sfRNA) production and its affinity for host proteins, which are necessary for successful viral replication. Indeed, we recently showed that mutations in DENV2 3′ UTR of epidemic strains increased sfRNA ability to bind host proteins and reduce interferon expression. However, whether 3′ UTR differences shape the overall DENV evolution remains incompletely understood. Herein, we combined RNA phylogeny with phylogenetics to gain insights on sfRNA evolution. We found that sfRNA structures are under purifying selection and highly conserved despite sequence divergence. Only the second flaviviral nuclease-resistant RNA (fNR2) structure of DENV2 sfRNA has undergone strong positive selection. Epidemiological reports suggest that substitutions in fNR2 may drive DENV2 epidemiological fitness, possibly through sfRNA-protein interactions. Collectively, our findings indicate that 3′ UTRs are important determinants of DENV fitness in human-mosquito cycles. Dengue viruses (DENVs) preserve RNA elements in their 3′ untranslated region (UTR). Quantification of natural selection revealed positive selection on DENV2 sfRNA Flaviviral nuclease-resistant RNAs (fNR) in the 3′ UTRs contribute to DENV speciation A highly evolving fNR structure appears to increase DENV2 epidemiological fitness
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Affiliation(s)
- Esteban Finol
- Programme in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore 169857, Singapore; Swiss Tropical and Public Health Institute, University of Basel, Basel 4051, Switzerland; Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117545, Singapore.
| | - Eng Eong Ooi
- Programme in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore 169857, Singapore; Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117545, Singapore; Saw Swee Hock School of Public Health, National University of Singapore, Singapore 117549, Singapore.
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63
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Cross ST, Michalski D, Miller MR, Wilusz J. RNA regulatory processes in RNA virus biology. WILEY INTERDISCIPLINARY REVIEWS-RNA 2019; 10:e1536. [PMID: 31034160 PMCID: PMC6697219 DOI: 10.1002/wrna.1536] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Accepted: 04/02/2019] [Indexed: 12/13/2022]
Abstract
Numerous post‐transcriptional RNA processes play a major role in regulating the quantity, quality and diversity of gene expression in the cell. These include RNA processing events such as capping, splicing, polyadenylation and modification, but also aspects such as RNA localization, decay, translation, and non‐coding RNA‐associated regulation. The interface between the transcripts of RNA viruses and the various RNA regulatory processes in the cell, therefore, has high potential to significantly impact virus gene expression, regulation, cytopathology and pathogenesis. Furthermore, understanding RNA biology from the perspective of an RNA virus can shed considerable light on the broad impact of these post‐transcriptional processes in cell biology. Thus the goal of this article is to provide an overview of the richness of cellular RNA biology and how RNA viruses use, usurp and/or avoid the associated machinery to impact the outcome of infection. This article is categorized under:RNA in Disease and Development > RNA in Disease
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Affiliation(s)
- Shaun T Cross
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado
| | - Daniel Michalski
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado
| | - Megan R Miller
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado
| | - Jeffrey Wilusz
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado
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64
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Filomatori CV, Bardossy ES, Merwaiss F, Suzuki Y, Henrion A, Saleh MC, Alvarez DE. RNA recombination at Chikungunya virus 3'UTR as an evolutionary mechanism that provides adaptability. PLoS Pathog 2019; 15:e1007706. [PMID: 30986247 PMCID: PMC6502353 DOI: 10.1371/journal.ppat.1007706] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Revised: 05/06/2019] [Accepted: 03/15/2019] [Indexed: 11/18/2022] Open
Abstract
The potential of RNA viruses to adapt to new environments relies on their ability to introduce changes in their genomes, which has resulted in the recent expansion of re-emergent viruses. Chikungunya virus is an important human pathogen transmitted by mosquitoes that, after 60 years of exclusive circulation in Asia and Africa, has rapidly spread in Europe and the Americas. Here, we examined the evolution of CHIKV in different hosts and uncovered host-specific requirements of the CHIKV 3'UTR. Sequence repeats are conserved at the CHIKV 3'UTR but vary in copy number among viral lineages. We found that these blocks of repeated sequences favor RNA recombination processes through copy-choice mechanism that acts concertedly with viral selection, determining the emergence of new viral variants. Functional analyses using a panel of mutant viruses indicated that opposite selective pressures in mosquito and mammalian cells impose a fitness cost during transmission that is alleviated by recombination guided by sequence repeats. Indeed, drastic changes in the frequency of viral variants with different numbers of repeats were detected during host switch. We propose that RNA recombination accelerates CHIKV adaptability, allowing the virus to overcome genetic bottlenecks within the mosquito host. These studies highlight the role of 3'UTR plasticity on CHIKV evolution, providing a new paradigm to explain the significance of sequence repetitions.
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Affiliation(s)
- Claudia V. Filomatori
- Instituto de Investigaciones Biotecnológicas, Universidad Nacional de San Martín, Buenos Aires, Argentina
| | - Eugenia S. Bardossy
- Instituto de Investigaciones Biotecnológicas, Universidad Nacional de San Martín, Buenos Aires, Argentina
| | - Fernando Merwaiss
- Instituto de Investigaciones Biotecnológicas, Universidad Nacional de San Martín, Buenos Aires, Argentina
| | - Yasutsugu Suzuki
- Institut Pasteur, Viruses and RNA Interference Unit, Centre National de la Recherche Scientifique UMR 3569, Paris, France
| | - Annabelle Henrion
- Institut Pasteur, Viruses and RNA Interference Unit, Centre National de la Recherche Scientifique UMR 3569, Paris, France
| | - María Carla Saleh
- Institut Pasteur, Viruses and RNA Interference Unit, Centre National de la Recherche Scientifique UMR 3569, Paris, France
| | - Diego E. Alvarez
- Instituto de Investigaciones Biotecnológicas, Universidad Nacional de San Martín, Buenos Aires, Argentina
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65
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Structure mapping of dengue and Zika viruses reveals functional long-range interactions. Nat Commun 2019; 10:1408. [PMID: 30926818 PMCID: PMC6441010 DOI: 10.1038/s41467-019-09391-8] [Citation(s) in RCA: 83] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Accepted: 03/08/2019] [Indexed: 02/02/2023] Open
Abstract
Dengue (DENV) and Zika (ZIKV) viruses are clinically important members of the Flaviviridae family with an 11 kb positive strand RNA genome that folds to enable virus function. Here, we perform structure and interaction mapping on four DENV and ZIKV strains inside virions and in infected cells. Comparative analysis of SHAPE reactivities across serotypes nominates potentially functional regions that are highly structured, conserved, and contain low synonymous mutation rates. Interaction mapping by SPLASH identifies many pair-wise interactions, 40% of which form alternative structures, suggesting extensive structural heterogeneity. Analysis of shared interactions between serotypes reveals a conserved macro-organization whereby interactions can be preserved at physical locations beyond sequence identities. We further observe that longer-range interactions are preferentially disrupted inside cells, and show the importance of new interactions in virus fitness. These findings deepen our understanding of Flavivirus genome organization and serve as a resource for designing therapeutics in targeting RNA viruses.
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Reyes-Ruiz JM, Osuna-Ramos JF, Bautista-Carbajal P, Jaworski E, Soto-Acosta R, Cervantes-Salazar M, Angel-Ambrocio AH, Castillo-Munguía JP, Chávez-Munguía B, De Nova-Ocampo M, Routh A, Del Ángel RM, Salas-Benito JS. Mosquito cells persistently infected with dengue virus produce viral particles with host-dependent replication. Virology 2019; 531:1-18. [PMID: 30844508 DOI: 10.1016/j.virol.2019.02.018] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 02/22/2019] [Accepted: 02/26/2019] [Indexed: 11/26/2022]
Abstract
Dengue viruses (DENV) are important arboviruses that can establish a persistent infection in its mosquito vector Aedes. Mosquitoes have a short lifetime in nature which makes trying to study the processes that take place during persistent viral infections in vivo. Therefore, C6/36 cells have been used to study this type of infection. C6/36 cells persistently infected with DENV 2 produce virions that cannot infect BHK -21 cells. We hypothesized that the following passages in mosquito cells have a deleterious impact on DENV fitness in vertebrate cells. Here, we demonstrated that the viral particles released from persistently infected cells were infectious to mosquito but not to vertebrate cells. This host restriction occurs at the replication level and is associated with several mutations in the DENV genome. In summary, our findings provide new information about viral replication fitness in a host-dependent manner.
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Affiliation(s)
- José Manuel Reyes-Ruiz
- Departamento de Infectómica y Patogénesis Molecular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico
| | - Juan Fidel Osuna-Ramos
- Departamento de Infectómica y Patogénesis Molecular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico
| | - Patricia Bautista-Carbajal
- Departamento de Infectómica y Patogénesis Molecular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico
| | - Elizabeth Jaworski
- Department of Biochemistry and Molecular Biology, The University of Texas, Medical Branch, Galveston, TX 77555, USA
| | - Rubén Soto-Acosta
- Department of Biochemistry and Molecular Biology, The University of Texas, Medical Branch, Galveston, TX 77555, USA
| | - Margot Cervantes-Salazar
- Departamento de Infectómica y Patogénesis Molecular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico
| | | | - Juan Pablo Castillo-Munguía
- Maestría en Ciencias en Biomedicina Molecular, Escuela Nacional de Medicina y Homeopatía, Instituto Politécnico Nacional, Mexico
| | - Bibiana Chávez-Munguía
- Departamento de Infectómica y Patogénesis Molecular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico
| | - Mónica De Nova-Ocampo
- Maestría en Ciencias en Biomedicina Molecular, Escuela Nacional de Medicina y Homeopatía, Instituto Politécnico Nacional, Mexico
| | - Andrew Routh
- Department of Biochemistry and Molecular Biology, The University of Texas, Medical Branch, Galveston, TX 77555, USA; Sealy Center for Structural Biology and Molecular Biophysics, The University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Rosa María Del Ángel
- Departamento de Infectómica y Patogénesis Molecular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico.
| | - Juan Santiago Salas-Benito
- Maestría en Ciencias en Biomedicina Molecular, Escuela Nacional de Medicina y Homeopatía, Instituto Politécnico Nacional, Mexico; Doctorado en Ciencias en Biotecnología, Escuela Nacional de Medicina y Homeopatía, Instituto Politécnico Nacional, Mexico.
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67
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Zhao W, Wang Q, Xu Z, Liu R, Cui F. Immune responses induced by different genotypes of the disease-specific protein of Rice stripe virus in the vector insect. Virology 2019; 527:122-131. [PMID: 30500711 DOI: 10.1016/j.virol.2018.11.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Revised: 11/15/2018] [Accepted: 11/17/2018] [Indexed: 01/25/2023]
Abstract
Persistent plant viruses circulate between host plants and vector insects, possibly leading to the genetic divergence in viral populations. We analyzed the single nucleotide polymorphisms (SNPs) of Rice stripe virus (RSV) when it incubated in the small brown planthopper and rice. Two SNPs, which lead to nonsynonymous substitutions in the disease-specific protein (SP) of RSV, produced three genotypes, i.e., GG, AA and GA. The GG type mainly existed in the early infection period of RSV in the planthoppers and was gradually substituted by the other two genotypes during viral transmission. The two SNPs did not affect the interactions of SP with rice PsbP or with RSV coat protein. The GG genotype of SP induced stronger immune responses than those of the other two genotypes in the pattern recognition molecule and immune-responsive effector pathways. These findings demonstrated the population variations of RSV during the circulation between the vector insect and host plant.
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Affiliation(s)
- Wan Zhao
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
| | - Qianshuo Wang
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China; Institute of Physical Science and Information Technology, Anhui University, Hefei, Anhui 230601, China
| | - Zhongtian Xu
- Shanghai Center for Plant Stress Biology, Chinese Academy of Sciences, Shanghai 201602, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Renyi Liu
- Center for Agroforestry Mega Data Science and FAFU-UCR Joint Center for Horticultural Biology and Metabolomics, Haixia Institute of Science and Technology, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Feng Cui
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China.
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68
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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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69
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Ahmad Z, Poh CL. The Conserved Molecular Determinants of Virulence in Dengue Virus. Int J Med Sci 2019; 16:355-365. [PMID: 30911269 PMCID: PMC6428985 DOI: 10.7150/ijms.29938] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Accepted: 12/17/2018] [Indexed: 12/22/2022] Open
Abstract
Dengue virus belongs to the Flaviviridae family which also includes viruses such as the Zika, West Nile and yellow fever virus. Dengue virus generally causes mild disease, however, more severe forms of the dengue virus infection, dengue haemorrhagic fever (DHF) and dengue haemorrhagic fever with shock syndrome (DSS) can also occur, resulting in multiple organ failure and even death, especially in children. The only dengue vaccine available in the market, CYD-TDV offers limited coverage for vaccinees from 9-45 years of age and is only recommended for individuals with prior dengue exposure. A number of mutations that were shown to attenuate virulence of dengue virus in vitro and/or in vivo have been identified in the literature. The mutations which fall within the conserved regions of all four dengue serotypes are discussed. This review hopes to provide information leading to the construction of a live attenuated dengue vaccine that is suitable for all ages, irrespective of the infecting dengue serotype and prior dengue exposure.
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Affiliation(s)
- Zuleeza Ahmad
- Centre for Virus and Vaccine Research, School of Science and Technology, Sunway University, 47500 Subang Jaya, Selangor, Malaysia
| | - Chit Laa Poh
- Centre for Virus and Vaccine Research, School of Science and Technology, Sunway University, 47500 Subang Jaya, Selangor, Malaysia
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70
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Soto-Acosta R, Xie X, Shan C, Baker CK, Shi PY, Rossi SL, Garcia-Blanco MA, Bradrick S. Fragile X mental retardation protein is a Zika virus restriction factor that is antagonized by subgenomic flaviviral RNA. eLife 2018; 7:39023. [PMID: 30511641 PMCID: PMC6279352 DOI: 10.7554/elife.39023] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Accepted: 11/12/2018] [Indexed: 12/19/2022] Open
Abstract
Subgenomic flaviviral RNA (sfRNA) accumulates during infection due to incomplete degradation of viral genomes and interacts with cellular proteins to promote infection. Here we identify host proteins that bind the Zika virus (ZIKV) sfRNA. We identified fragile X mental retardation protein (FMRP) as a ZIKV sfRNA-binding protein and confirmed this interaction in cultured cells and mouse testes. Depletion of FMRP elevated viral translation and enhanced ZIKV infection, indicating that FMRP is a ZIKV restriction factor. We further observed that an attenuated ZIKV strain compromised for sfRNA production was disproportionately stimulated by FMRP knockdown, suggesting that ZIKV sfRNA antagonizes FMRP activity. Importantly, ZIKV infection and expression of ZIKV sfRNA upregulated endogenous FMRP target genes in cell culture and ZIKV-infected mice. Together, our observations identify FMRP as a ZIKV restriction factor whose activity is antagonized by the sfRNA. Interaction between ZIKV and FMRP has significant implications for the pathogenesis of ZIKV infections.
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Affiliation(s)
- Ruben Soto-Acosta
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, United States
| | - Xuping Xie
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, United States
| | - Chao Shan
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, United States
| | - Coleman K Baker
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, United States
| | - Pei-Yong Shi
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, United States.,Sealy Center for Vaccine Development, University of Texas Medical Branch, Galveston, United States.,Department of Pharmacology & Toxicology, University of Texas Medical Branch, Galveston, United States.,Sealy Center for Structural Biology & Molecular Biophysics, University of Texas Medical Branch, Galveston, United States.,Institute for Human Infections & Immunity, University of Texas Medical Branch, Galveston, United States
| | - Shannan L Rossi
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, United States.,Institute for Human Infections & Immunity, University of Texas Medical Branch, Galveston, United States.,Department of Pathology, University of Texas Medical Branch, Galveston, United States.,Center for Biodefense & Emerging Infectious Diseases, University of Texas Medical Branch, Galveston, United States
| | - Mariano A Garcia-Blanco
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, United States.,Institute for Human Infections & Immunity, University of Texas Medical Branch, Galveston, United States.,Programme in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore, Singapore
| | - Shelton Bradrick
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, United States.,Institute for Human Infections & Immunity, University of Texas Medical Branch, Galveston, United States.,Center for Biodefense & Emerging Infectious Diseases, University of Texas Medical Branch, Galveston, United States
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71
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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: 72] [Impact Index Per Article: 10.3] [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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72
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Liu X, Liu Y, Zhang Q, Zhang B, Xia H, Yuan Z. Homologous RNA secondary structure duplications in 3′ untranslated region influence subgenomic RNA production and replication of dengue virus. Virology 2018; 524:114-126. [DOI: 10.1016/j.virol.2018.08.018] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Revised: 08/18/2018] [Accepted: 08/21/2018] [Indexed: 10/28/2022]
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73
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Slonchak A, Khromykh AA. Subgenomic flaviviral RNAs: What do we know after the first decade of research. Antiviral Res 2018; 159:13-25. [PMID: 30217649 DOI: 10.1016/j.antiviral.2018.09.006] [Citation(s) in RCA: 83] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Revised: 09/10/2018] [Accepted: 09/10/2018] [Indexed: 12/13/2022]
Abstract
The common feature of flaviviral infection is the accumulation of abundant virus-derived noncoding RNA, named flaviviral subgenomic RNA (sfRNA) in infected cells. This RNA represents a product of incomplete degradation of viral genomic RNA by the cellular 5'-3' exoribonuclease XRN1 that stalls at the conserved highly structured elements in the 3' untranslated region (UTR). This mechanism of sfRNA generation was discovered a decade ago and since then sfRNA has been a focus of intense research. The ability of flaviviruses to produce sfRNA was shown to be evolutionary conserved in all members of Flavivirus genus. Mutations in the 3'UTR that affect production of sfRNAs and their interactions with host factors showed that sfRNAs are responsible for viral pathogenicity, host adaptation, and emergence of new pathogenic strains. RNA structural elements required for XRN1 stalling have been elucidated and the role of sfRNAs in inhibiting host antiviral responses in arthropod and vertebrate hosts has been demonstrated. Some molecular mechanisms determining these properties of sfRNA have been recently characterized, while other aspects of sfRNA functions remain an open avenue for future research. In this review we summarise the current state of knowledge on the mechanisms of generation and functional roles of sfRNAs in the life cycle of flaviviruses and highlight the gaps in our knowledge to be addressed in the future.
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Affiliation(s)
- Andrii Slonchak
- The Australian Infectious Disease Centre, School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, QLD, 4072, Australia
| | - Alexander A Khromykh
- The Australian Infectious Disease Centre, School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, QLD, 4072, Australia.
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74
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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: 2.6] [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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75
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Chen YS, Fan YH, Tien CF, Yueh A, Chang RY. The conserved stem-loop II structure at the 3' untranslated region of Japanese encephalitis virus genome is required for the formation of subgenomic flaviviral RNA. PLoS One 2018; 13:e0201250. [PMID: 30048535 PMCID: PMC6062100 DOI: 10.1371/journal.pone.0201250] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2018] [Accepted: 07/11/2018] [Indexed: 01/02/2023] Open
Abstract
Flaviviruses accumulate abundant subgenomic RNA (sfRNA) in infected cells. It has been reported that sfRNA results from stalling of host 5’-to-3’ exoribonuclease XRN1 at the highly structured RNA of the 3’ untranslated region (UTR). Although XRN1 digestion of a 3’-terminal 800-nt RNA could stall at a position to generate the sfRNA in vitro, we found that knocking out XRN1 had no effect on the accumulation of sfRNA in Japanese encephalitis virus (JEV) infected cells. Mutagenesis studies revealed that the stemloop II (SLII) at the 3’ UTR is required for the accumulation of sfRNA. According to the results of an in vitro RNA-dependent RNA polymerase (RdRp) assay, the (-)10431-10566 RNA fragment, containing the putative promoter on the antigenome for the sfRNA transcription, binds to RdRp protein and exhibits a strong promoter activity. Taken together, our results indicate that the JEV sfRNA could be transcribed initially and then be trimmed by XRN1 or other unidentified exoribonucleases.
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Affiliation(s)
- Yi-Shiuan Chen
- Department of Life Science, National Dong Hwa University, Hualien, Taiwan, ROC
| | - Yi-Hsin Fan
- Department of Life Science, National Dong Hwa University, Hualien, Taiwan, ROC
| | - Chih-Feng Tien
- Department of Life Science, National Dong Hwa University, Hualien, Taiwan, ROC
| | - Andrew Yueh
- Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Miaoli, Taiwan, ROC
| | - Ruey-Yi Chang
- Department of Life Science, National Dong Hwa University, Hualien, Taiwan, ROC
- * E-mail:
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76
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Beaver JT, Lelutiu N, Habib R, Skountzou I. Evolution of Two Major Zika Virus Lineages: Implications for Pathology, Immune Response, and Vaccine Development. Front Immunol 2018; 9:1640. [PMID: 30072993 PMCID: PMC6058022 DOI: 10.3389/fimmu.2018.01640] [Citation(s) in RCA: 74] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Accepted: 07/03/2018] [Indexed: 12/13/2022] Open
Abstract
Zika virus (ZIKV) became a public health emergency of global concern in 2015 due to its rapid expansion from French Polynesia to Brazil, spreading quickly throughout the Americas. Its unexpected correlation to neurological impairments and defects, now known as congenital Zika syndrome, brought on an urgency to characterize the pathology and develop safe, effective vaccines. ZIKV genetic analyses have identified two major lineages, Asian and African, which have undergone substantial changes during the past 50 years. Although ZIKV infections have been circulating throughout Africa and Asia for the later part of the 20th century, the symptoms were mild and not associated with serious pathology until now. ZIKV evolution also took the form of novel modes of transmission, including maternal-fetal transmission, sexual transmission, and transmission through the eye. The African and Asian lineages have demonstrated differential pathogenesis and molecular responses in vitro and in vivo. The limited number of human infections prior to the 21st century restricted ZIKV research to in vitro studies, but current animal studies utilize mice deficient in type I interferon (IFN) signaling in order to invoke enhanced viral pathogenesis. This review examines ZIKV strain differences from an evolutionary perspective, discussing how these differentially impact pathogenesis via host immune responses that modulate IFN signaling, and how these differential effects dictate the future of ZIKV vaccine candidates.
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Affiliation(s)
| | | | | | - Ioanna Skountzou
- Department of Microbiology and Immunology, Emory Vaccine Center, Emory University School of Medicine, Atlanta, GA, United States
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77
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Decreased accumulation of subgenomic RNA in human cells infected with vaccine candidate DEN4Δ30 increases viral susceptibility to type I interferon. Vaccine 2018; 36:3460-3467. [PMID: 29752023 DOI: 10.1016/j.vaccine.2018.04.087] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Revised: 04/19/2018] [Accepted: 04/20/2018] [Indexed: 11/20/2022]
Abstract
The NIH has developed live attenuated dengue virus (DENV) vaccine candidates by deletion of 30 nucleotides (Δ30) from the untranslated region of the viral genome. Although this attenuation strategy has proven to be effective in generating safe and immunogenic vaccine strains, the molecular mechanism of attenuation is largely unknown. To examine the mediators of the observed attenuation phenotype, differences in translation efficiency, genome replication, cytotoxicity, and type I interferon susceptibility were compared between wild type parental DENV and DENVΔ30 attenuated vaccine candidates. We observed that decreased accumulation of subgenomic RNA (sfRNA) from the vaccine candidates in infected human cells causes increased type I IFN susceptibility and propose this as one of the of attenuation mechanisms produced by the 3' UTR Δ30 mutation.
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78
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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: 228] [Impact Index Per Article: 32.6] [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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79
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Lourenço J, Tennant W, Faria NR, Walker A, Gupta S, Recker M. Challenges in dengue research: A computational perspective. Evol Appl 2018; 11:516-533. [PMID: 29636803 PMCID: PMC5891037 DOI: 10.1111/eva.12554] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Accepted: 09/08/2017] [Indexed: 01/12/2023] Open
Abstract
The dengue virus is now the most widespread arbovirus affecting human populations, causing significant economic and social impact in South America and South-East Asia. Increasing urbanization and globalization, coupled with insufficient resources for control, misguided policies or lack of political will, and expansion of its mosquito vectors are some of the reasons why interventions have so far failed to curb this major public health problem. Computational approaches have elucidated on dengue's population dynamics with the aim to provide not only a better understanding of the evolution and epidemiology of the virus but also robust intervention strategies. It is clear, however, that these have been insufficient to address key aspects of dengue's biology, many of which will play a crucial role for the success of future control programmes, including vaccination. Within a multiscale perspective on this biological system, with the aim of linking evolutionary, ecological and epidemiological thinking, as well as to expand on classic modelling assumptions, we here propose, discuss and exemplify a few major computational avenues-real-time computational analysis of genetic data, phylodynamic modelling frameworks, within-host model frameworks and GPU-accelerated computing. We argue that these emerging approaches should offer valuable research opportunities over the coming years, as previously applied and demonstrated in the context of other pathogens.
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Affiliation(s)
| | - Warren Tennant
- Centre for Mathematics and the EnvironmentUniversity of ExeterPenrynUK
| | | | | | | | - Mario Recker
- Centre for Mathematics and the EnvironmentUniversity of ExeterPenrynUK
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80
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Mechanism and structural diversity of exoribonuclease-resistant RNA structures in flaviviral RNAs. Nat Commun 2018; 9:119. [PMID: 29317714 PMCID: PMC5760640 DOI: 10.1038/s41467-017-02604-y] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2017] [Accepted: 12/12/2017] [Indexed: 01/21/2023] Open
Abstract
Flaviviruses such as Yellow fever, Dengue, West Nile, and Zika generate disease-linked viral noncoding RNAs called subgenomic flavivirus RNAs. Subgenomic flavivirus RNAs result when the 5'-3' progression of cellular exoribonuclease Xrn1 is blocked by RNA elements called Xrn1-resistant RNAs located within the viral genome's 3'-untranslated region that operate without protein co-factors. Here, we show that Xrn1-resistant RNAs can halt diverse exoribonucleases, revealing a mechanism in which they act as general mechanical blocks that 'brace' against an enzyme's surface, presenting an unfolding problem that confounds further enzyme progression. Further, we directly demonstrate that Xrn1-resistant RNAs exist in a diverse set of flaviviruses, including some specific to insects or with no known arthropod vector. These Xrn1-resistant RNAs comprise two secondary structural classes that mirror previously reported phylogenic analysis. Our discoveries have implications for the evolution of exoribonuclease resistance, the use of Xrn1-resistant RNAs in synthetic biology, and the development of new therapies.
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81
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How Do Virus-Mosquito Interactions Lead to Viral Emergence? Trends Parasitol 2018; 34:310-321. [PMID: 29305089 DOI: 10.1016/j.pt.2017.12.004] [Citation(s) in RCA: 75] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Revised: 12/11/2017] [Accepted: 12/13/2017] [Indexed: 12/27/2022]
Abstract
Arboviruses such as West Nile, Zika, chikungunya, dengue, and yellow fever viruses have become highly significant global pathogens through unexpected, explosive outbreaks. While the rapid progression and frequency of recent arbovirus outbreaks is associated with long-term changes in human behavior (globalization, urbanization, climate change), there are direct mosquito-virus interactions which drive shifts in host range and alter virus transmission. This review summarizes how virus-mosquito interactions are critical for these viruses to become global pathogens at molecular, physiological, evolutionary, and epidemiological scales. Integrated proactive approaches are required in order to effectively manage the emergence of mosquito-borne arboviruses, which appears likely to continue into the indefinite future.
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82
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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: 1.0] [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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83
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Yeh SC, Pompon J. Flaviviruses Produce a Subgenomic Flaviviral RNA That Enhances Mosquito Transmission. DNA Cell Biol 2017; 37:154-159. [PMID: 29251994 DOI: 10.1089/dna.2017.4059] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Mosquito-borne flaviviruses (MBFVs) are a global public health burden. MBFVs have several unique 3'UTR structures that inhibit the host RNA decay machinery to produce subgenomic flaviviral RNAs (sfRNAs). Number of sfRNA species and their relative quantities are dependent on the 3'UTR tertiary structures and can vary between tissues. Two recent in vivo studies demonstrated that sfRNA enhances mosquito transmission, resulting in increased infection rate of saliva. Transmission efficiency is determined by the immune response. First evidence points to sfRNA interference with the Toll and RNAi immune pathways. However, a more complex picture that includes flexibility in sfRNA production and interaction with immune-related proteins remains to be explored.
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Affiliation(s)
- Shih-Chia Yeh
- 1 Programme in Emerging Infectious Diseases, Duke-National University of Singapore Medical School , Singapore, Singapore
| | - Julien Pompon
- 1 Programme in Emerging Infectious Diseases, Duke-National University of Singapore Medical School , Singapore, Singapore .,2 MIVEGEC, IRD, CNRS, University of Montpellier , Montpellier, France
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84
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Miorin L, Maestre AM, Fernandez-Sesma A, García-Sastre A. Antagonism of type I interferon by flaviviruses. Biochem Biophys Res Commun 2017; 492:587-596. [PMID: 28576494 PMCID: PMC5626595 DOI: 10.1016/j.bbrc.2017.05.146] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2017] [Revised: 05/20/2017] [Accepted: 05/24/2017] [Indexed: 12/24/2022]
Abstract
The prompt and tightly controlled induction of type I interferon is a central event of the immune defense against viral infection. Flaviviruses comprise a large family of arthropod-borne positive-stranded RNA viruses, many of which represent a serious threat to global human health due to their high rates of morbidity and mortality. All flaviviruses studied so far have been shown to counteract the host's immune response to establish a productive infection and facilitate viral spread. Here, we review the current knowledge on the main strategies that human pathogenic flaviviruses utilize to escape both type I IFN induction and effector pathways. A better understanding of the specific mechanisms by which flaviviruses activate and evade innate immune responses is critical for the development of better therapeutics and vaccines.
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Affiliation(s)
- Lisa Miorin
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, United States; Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, United States
| | - Ana M Maestre
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, United States
| | - Ana Fernandez-Sesma
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, United States; Department of Medicine, Division of Infectious Diseases, Icahn School of Medicine at Mount Sinai, New York, NY 10029, United States.
| | - Adolfo García-Sastre
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, United States; Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, United States; Department of Medicine, Division of Infectious Diseases, Icahn School of Medicine at Mount Sinai, New York, NY 10029, United States.
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85
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Arbovirus Adaptation: Roles in Transmission and Emergence. CURRENT CLINICAL MICROBIOLOGY REPORTS 2017. [DOI: 10.1007/s40588-017-0068-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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86
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Göertz GP, Abbo SR, Fros JJ, Pijlman GP. Functional RNA during Zika virus infection. Virus Res 2017; 254:41-53. [PMID: 28864425 DOI: 10.1016/j.virusres.2017.08.015] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Revised: 08/28/2017] [Accepted: 08/28/2017] [Indexed: 12/24/2022]
Abstract
Zika virus (ZIKV; family Flaviviridae; genus Flavivirus) is a pathogenic mosquito-borne RNA virus that currently threatens human health in the Americas, large parts of Asia and occasionally elsewhere in the world. ZIKV infection is often asymptomatic but can cause severe symptoms including congenital microcephaly and Guillain-Barré syndrome. The positive single-stranded RNA genome of the mosquito-borne ZIKV requires effective replication in two evolutionary distinct hosts - mosquitoes and primates. In addition to some of the viral proteins, the ZIKV genomic RNA and functional RNAs produced thereof aid in the establishment of productive infection and the evasion of host cell antiviral responses. ZIKV has evolved to contain a nucleotide composition and RNA modifications, such as methylation and the formation of G-quadruplexes that allow effective replication in both hosts. Furthermore, a number of host factors interact with the viral genome to modulate RNA replication. Importantly, the ZIKV genome produces non-coding subgenomic flavivirus RNA (sfRNA) due to stalling of host 5'- 3' ribonucleases on viral RNA structures in the 3' untranslated region (UTR). This sfRNA (sfRNA) exerts important proviral functions such as antagonizing the innate interferon response and RNA interference. Here, we discuss the ZIKV genomic RNA and functional RNAs thereof to assess their significance during ZIKV infection. Understanding the details of the ZIKV infection cycle will aid in the development of effective antiviral strategies and safe vaccines.
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Affiliation(s)
- Giel P Göertz
- Laboratory of Virology, Wageningen University & Research, Wageningen, The Netherlands.
| | - Sandra R Abbo
- Laboratory of Virology, Wageningen University & Research, Wageningen, The Netherlands.
| | - Jelke J Fros
- Laboratory of Virology, Wageningen University & Research, Wageningen, The Netherlands; Nuffield Department of Medicine, Peter Medawar Building for Pathogen Research, University of Oxford, Oxford, UK.
| | - Gorben P Pijlman
- Laboratory of Virology, Wageningen University & Research, Wageningen, The Netherlands.
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87
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Pompon J, Manuel M, Ng GK, Wong B, Shan C, Manokaran G, Soto-Acosta R, Bradrick SS, Ooi EE, Missé D, Shi PY, Garcia-Blanco MA. Dengue subgenomic flaviviral RNA disrupts immunity in mosquito salivary glands to increase virus transmission. PLoS Pathog 2017; 13:e1006535. [PMID: 28753642 PMCID: PMC5555716 DOI: 10.1371/journal.ppat.1006535] [Citation(s) in RCA: 87] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Revised: 08/14/2017] [Accepted: 07/15/2017] [Indexed: 12/21/2022] Open
Abstract
Globally re-emerging dengue viruses are transmitted from human-to-human by Aedes mosquitoes. While viral determinants of human pathogenicity have been defined, there is a lack of knowledge of how dengue viruses influence mosquito transmission. Identification of viral determinants of transmission can help identify isolates with high epidemiological potential. Additionally, mechanistic understanding of transmission will lead to better understanding of how dengue viruses harness evolution to cycle between the two hosts. Here, we identified viral determinants of transmission and characterized mechanisms that enhance production of infectious saliva by inhibiting immunity specifically in salivary glands. Combining oral infection of Aedes aegypti mosquitoes and reverse genetics, we identified two 3’ UTR substitutions in epidemic isolates that increased subgenomic flaviviral RNA (sfRNA) quantity, infectious particles in salivary glands and infection rate of saliva, which represents a measure of transmission. We also demonstrated that various 3’UTR modifications similarly affect sfRNA quantity in both whole mosquitoes and human cells, suggesting a shared determinism of sfRNA quantity. Furthermore, higher relative quantity of sfRNA in salivary glands compared to midgut and carcass pointed to sfRNA function in salivary glands. We showed that the Toll innate immune response was preferentially inhibited in salivary glands by viruses with the 3’UTR substitutions associated to high epidemiological fitness and high sfRNA quantity, pointing to a mechanism for higher saliva infection rate. By determining that sfRNA is an immune suppressor in a tissue relevant to mosquito transmission, we propose that 3’UTR/sfRNA sequence evolution shapes dengue epidemiology not only by influencing human pathogenicity but also by increasing mosquito transmission, thereby revealing a viral determinant of epidemiological fitness that is shared between the two hosts. Dengue is a re-emerging global disease transmitted from human-to-human by mosquitoes. While environmental and host immune factors are important, viral determinants of mosquito transmission also shape the epidemiology of dengue. Understanding how dengue viruses influence transmission will help identify isolates with high epidemic potential and untangle the evolutionary pressures at play in the dual-host cycle. Here, we identified 2 substitutions in the 3’UTR of epidemic isolates that increase transmission through immune suppression in the salivary glands. Using oral infection of Aedes aegypti mosquitoes, we reported that epidemic isolates produced more subgenomic flaviviral RNA (sfRNA) in salivary glands. SfRNA is generated from the 3’UTR sequence remaining after partial genome degradation by a host nuclease. Using reverse genetics, we identified the two 3’UTR substitutions responsible for the higher sfRNA quantity in salivary glands. We further showed that these substitutions increased dengue virus titer in salivary glands and rate of saliva infection, and suppressed the Toll immune response in salivary glands. Our study identifies the substitutions that determine virus epidemiological fitness and provides a mechanism for sfRNA-mediated enhancement of transmission. Together with previous work demonstrating that sfRNA sequence modification influences dengue virus pathogenicity in human, and that shows variation in sfRNA sequence when the viruses transition from one host to vector and vice versa, our study supports that sfRNA evolution is constrained in the two hosts.
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Affiliation(s)
- Julien Pompon
- Programme in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore
- UMR IRD-CNRS MIVEGEC, IRD, Montpellier, France
- * E-mail: (JP); (MAGB)
| | - Menchie Manuel
- Programme in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore
| | - Geok Kee Ng
- Programme in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore
| | - Benjamin Wong
- Programme in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore
| | - Chao Shan
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX, United States of America
| | - Gayathri Manokaran
- Programme in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore
| | - Ruben Soto-Acosta
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX, United States of America
| | - Shelton S. Bradrick
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX, United States of America
| | - Eng Eong Ooi
- Programme in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore
| | | | - Pei-Yong Shi
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX, United States of America
| | - Mariano A. Garcia-Blanco
- Programme in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX, United States of America
- * E-mail: (JP); (MAGB)
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88
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Hamlin RE, Rahman A, Pak TR, Maringer K, Mena I, Bernal-Rubio D, Potla U, Maestre AM, Fredericks AC, Amir EAD, Kasarskis A, Ramos I, Merad M, Fernandez-Sesma A. High-dimensional CyTOF analysis of dengue virus-infected human DCs reveals distinct viral signatures. JCI Insight 2017; 2:92424. [PMID: 28679950 PMCID: PMC5499363 DOI: 10.1172/jci.insight.92424] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Accepted: 05/19/2017] [Indexed: 01/11/2023] Open
Abstract
Dengue virus (DENV) is the most prevalent mosquito-borne virus causing human disease. Of the 4 DENV serotypes, epidemiological data suggest that DENV-2 secondary infections are associated with more severe disease than DENV-4 infections. Mass cytometry by time-of-flight (CyTOF) was used to dissect immune changes induced by DENV-2 and DENV-4 in human DCs, the initial targets of primary infections that likely affect infection outcomes. Strikingly, DENV-4 replication peaked earlier and promoted stronger innate immune responses, with increased expression of DC activation and migration markers and increased cytokine production, compared with DENV-2. In addition, infected DCs produced higher levels of inflammatory cytokines compared with bystander DCs, which mainly produced IFN-induced cytokines. These high-dimensional analyses during DENV-2 and DENV-4 infections revealed distinct viral signatures marked by different replication strategies and antiviral innate immune induction in DCs, which may result in different viral fitness, transmission, and pathogenesis.
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Affiliation(s)
| | - Adeeb Rahman
- Human Immune Monitoring Core
- Department of Genetics and Genomic Sciences, and
| | - Theodore R. Pak
- Graduate School of Biomedical Sciences
- Department of Genetics and Genomic Sciences, and
- Icahn Institute for Genomics and Multiscale Biology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Kevin Maringer
- Department of Microbiology
- Department of Microbial Sciences, Faculty of Health and Medical Sciences, University of Surrey, Guildford Surrey, United Kingdom
| | | | | | | | | | | | - El-ad D. Amir
- Human Immune Monitoring Core
- Department of Oncological Sciences, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Andrew Kasarskis
- Graduate School of Biomedical Sciences
- Department of Genetics and Genomic Sciences, and
- Icahn Institute for Genomics and Multiscale Biology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | | | - Miriam Merad
- Graduate School of Biomedical Sciences
- Human Immune Monitoring Core
- Department of Oncological Sciences, Icahn School of Medicine at Mount Sinai, New York, New York, USA
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The 5' and 3' Untranslated Regions of the Flaviviral Genome. Viruses 2017; 9:v9060137. [PMID: 28587300 PMCID: PMC5490814 DOI: 10.3390/v9060137] [Citation(s) in RCA: 122] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Revised: 05/16/2017] [Accepted: 05/29/2017] [Indexed: 01/30/2023] Open
Abstract
Flaviviruses are enveloped arthropod-borne viruses with a single-stranded, positive-sense RNA genome that can cause serious illness in humans and animals. The 11 kb 5′ capped RNA genome consists of a single open reading frame (ORF), and is flanked by 5′ and 3′ untranslated regions (UTR). The ORF is a polyprotein that is processed into three structural and seven non-structural proteins. The UTRs have been shown to be important for viral replication and immune modulation. Both of these regions consist of elements that are essential for genome cyclization, resulting in initiation of RNA synthesis. Genome mutation studies have been employed to investigate each component of the essential elements to show the necessity of each component and its role in viral RNA replication and growth. Furthermore, the highly structured 3′UTR is responsible for the generation of subgenomic flavivirus RNA (sfRNA) that helps the virus evade host immune response, thereby affecting viral pathogenesis. In addition, changes within the 3′UTR have been shown to affect transmissibility between vector and host, which can influence the development of vaccines.
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