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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: 176] [Impact Index Per Article: 29.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [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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Černý J, Selinger M, Palus M, Vavrušková Z, Tykalová H, Bell-Sakyi L, Štěrba J, Grubhoffer L, Růžek D. Expression of a second open reading frame present in the genome of tick-borne encephalitis virus strain Neudoerfl is not detectable in infected cells. Virus Genes 2016; 52:309-16. [PMID: 26924586 DOI: 10.1007/s11262-015-1273-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2015] [Accepted: 12/10/2015] [Indexed: 12/30/2022]
Abstract
A short upstream open reading frame (uORF) was recently identified in the 5' untranslated region of some tick-borne encephalitis virus (TBEV) strains. However, it is not known if the peptide encoded by TBEV uORF (TuORF) is expressed in infected cells. Here we show that TuORF forms three phylogenetically separated clades which are typical of European, Siberian, and Far-Eastern TBEV subtypes. Analysis of selection pressure acting on the TuORF area showed that it is under positive selection pressure. Theoretically, TuORF may code for a short hydrophobic peptide embedded in a biological membrane. However, expression of TuORF was detectable neither by immunoblotting in tick and mammalian cell lines infected with TBEV nor by immunofluorescence in TBEV-infected mammalian cell lines. These results support the idea that TuORF is not expressed in TBEV-infected cell or expressed in undetectably low concentrations. Therefore we can assume that TuORF has either minor or no biological role in the TBEV life cycle.
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Affiliation(s)
- Jiří Černý
- Institute of Parasitology, Biology Centre of the Czech Academy of Sciences, Branišovská 31, 370 05, České Budějovice, Czech Republic. .,Faculty of Science, University of South Bohemia in České Budějovice, Branišovská 31, 370 05, České Budějovice, Czech Republic. .,Veterinary Research Institute, Hudcova 296/70, 621 00, Brno, Czech Republic.
| | - Martin Selinger
- Institute of Parasitology, Biology Centre of the Czech Academy of Sciences, Branišovská 31, 370 05, České Budějovice, Czech Republic.,Faculty of Science, University of South Bohemia in České Budějovice, Branišovská 31, 370 05, České Budějovice, Czech Republic
| | - Martin Palus
- Institute of Parasitology, Biology Centre of the Czech Academy of Sciences, Branišovská 31, 370 05, České Budějovice, Czech Republic.,Faculty of Science, University of South Bohemia in České Budějovice, Branišovská 31, 370 05, České Budějovice, Czech Republic.,Veterinary Research Institute, Hudcova 296/70, 621 00, Brno, Czech Republic
| | - Zuzana Vavrušková
- Institute of Parasitology, Biology Centre of the Czech Academy of Sciences, Branišovská 31, 370 05, České Budějovice, Czech Republic
| | - Hana Tykalová
- Institute of Parasitology, Biology Centre of the Czech Academy of Sciences, Branišovská 31, 370 05, České Budějovice, Czech Republic.,Faculty of Science, University of South Bohemia in České Budějovice, Branišovská 31, 370 05, České Budějovice, Czech Republic
| | - Lesley Bell-Sakyi
- The Pirbright Institute, Ash Road, Pirbright, Woking, Surrey, GU24 0NF, UK
| | - Ján Štěrba
- Institute of Parasitology, Biology Centre of the Czech Academy of Sciences, Branišovská 31, 370 05, České Budějovice, Czech Republic.,Faculty of Science, University of South Bohemia in České Budějovice, Branišovská 31, 370 05, České Budějovice, Czech Republic
| | - Libor Grubhoffer
- Institute of Parasitology, Biology Centre of the Czech Academy of Sciences, Branišovská 31, 370 05, České Budějovice, Czech Republic.,Faculty of Science, University of South Bohemia in České Budějovice, Branišovská 31, 370 05, České Budějovice, Czech Republic
| | - Daniel Růžek
- Institute of Parasitology, Biology Centre of the Czech Academy of Sciences, Branišovská 31, 370 05, České Budějovice, Czech Republic.,Veterinary Research Institute, Hudcova 296/70, 621 00, Brno, Czech Republic
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Bet A, Maze EA, Bansal A, Sterrett S, Gross A, Graff-Dubois S, Samri A, Guihot A, Katlama C, Theodorou I, Mesnard JM, Moris A, Goepfert PA, Cardinaud S. The HIV-1 antisense protein (ASP) induces CD8 T cell responses during chronic infection. Retrovirology 2015; 12:15. [PMID: 25809376 PMCID: PMC4335690 DOI: 10.1186/s12977-015-0135-y] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2014] [Accepted: 01/05/2015] [Indexed: 12/18/2022] Open
Abstract
Background CD8+ T cells recognize HIV-1 epitopes translated from a gene’s primary reading frame (F1) and any one of its five alternative reading frames (ARFs) in the forward (F2, F3) or reverse (R1-3) directions. The 3’ end of HIV-1’s proviral coding strand contains a conserved sequence that is directly overlapping but antiparallel to the env gene (ARF R2) and encodes for a putative antisense HIV-1 protein called ASP. ASP expression has been demonstrated in vitro using HIV-transfected cell lines or infected cells. Although antibodies to ASP were previously detected in patient sera, T cell recognition of ASP-derived epitopes has not been evaluated. We therefore investigated the ex vivo and in vitro induction of ASP-specific T cell responses as a measure of immune recognition and protein expression during HIV-1 infection. Results A panel of overlapping peptides was initially designed from the full-length ASP sequence to perform a global assessment of T cell responses. Recognition of ASP-derived antigens was evaluated in an IFN-γELISpot assay using PBMCs from HIV-1 seropositive and seronegative individuals. Eight of 25 patients had positive responses to ASP antigens and none of the seronegative donors responded. As a complimentary approach, a second set of antigens was designed using HLA-I binding motifs and affinities. Two ASP-derived peptides with high predicted binding affinities for HLA-A*02 (ASP-YL9) and HLA-B*07 (ASP-TL10) were tested using PBMCs from HIV-1 seropositive and seronegative individuals who expressed the matching HLA-I-restricting allele. We found that HLA-I-restricted ASP peptides were only recognized by CD8+ T cells from patients with the relevant HLA-I and did not induce responses in any of the seronegative donors or patients who do not express the restrictive HLA alleles. Further, ASP-YL9-specific CD8+ T cells had functional profiles that were similar to a previously described HLA-A*02-restricted epitope (Gag-SL9). Specific recognition of ASP-YL9 by CD8+ T cells was also demonstrated by tetramer staining using cells from an HLA-A*02 HIV-infected patient. Conclusion Our results provide the first description of CD8+ T cell-mediated immune responses to ASP in HIV-1-infected patients, demonstrating that ASP is expressed during infection. Our identification of epitopes within ASP has implications for designing HIV vaccines. Electronic supplementary material The online version of this article (doi:10.1186/s12977-015-0135-y) contains supplementary material, which is available to authorized users.
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Brinton MA. Replication cycle and molecular biology of the West Nile virus. Viruses 2013; 6:13-53. [PMID: 24378320 DOI: 10.3390/v6010013] [Citation(s) in RCA: 95] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2013] [Revised: 12/12/2013] [Accepted: 12/12/2013] [Indexed: 12/27/2022] Open
Abstract
West Nile virus (WNV) is a member of the genus Flavivirus in the family Flaviviridae. Flaviviruses replicate in the cytoplasm of infected cells and modify the host cell environment. Although much has been learned about virion structure and virion-endosomal membrane fusion, the cell receptor(s) used have not been definitively identified and little is known about the early stages of the virus replication cycle. Members of the genus Flavivirus differ from members of the two other genera of the family by the lack of a genomic internal ribosomal entry sequence and the creation of invaginations in the ER membrane rather than double-membrane vesicles that are used as the sites of exponential genome synthesis. The WNV genome 3' and 5' sequences that form the long distance RNA-RNA interaction required for minus strand initiation have been identified and contact sites on the 5' RNA stem loop for NS5 have been mapped. Structures obtained for many of the viral proteins have provided information relevant to their functions. Viral nonstructural protein interactions are complex and some may occur only in infected cells. Although interactions between many cellular proteins and virus components have been identified, the functions of most of these interactions have not been delineated.
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Faggioni G, Pomponi A, De Santis R, Masuelli L, Ciammaruconi A, Monaco F, Di Gennaro A, Marzocchella L, Sambri V, Lelli R, Rezza G, Bei R, Lista F. West Nile alternative open reading frame (N-NS4B/WARF4) is produced in infected West Nile Virus (WNV) cells and induces humoral response in WNV infected individuals. Virol J 2012; 9:283. [PMID: 23173701 PMCID: PMC3574045 DOI: 10.1186/1743-422x-9-283] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2011] [Accepted: 11/12/2012] [Indexed: 01/29/2023] Open
Abstract
Background West Nile Virus (WNV) is a flavivirus that requires an efficient humoral and cellular host response for the control of neuroinvasive infection. We previously reported the existence of six alternative open reading frame proteins in WNV genome, one of which entitled WARF4 is exclusively restricted to the lineage I of the virus. WARF4 is able to elicit antibodies in WNV infected horses; however, there was no direct experimental proof of the existence of this novel protein. The purpose of this study was to demonstrate the in vitro production of WARF4 protein following WNV infection of cultured VERO cells and its immunity in WNV infected individuals. Results We produced a monoclonal antibody against WARF4 protein (MAb 3A12) which detected the novel protein in WNV lineage I-infected, cultured VERO cells while it did not react with WNV lineage II infected cells. MAb 3A12 specificity to WARF4 protein was confirmed by its reactivity to only one peptide among four analyzed that cover the full WARF4 amino acids sequence. In addition, WARF4 protein was expressed in the late phase of WNV lineage I infection. Western blotting and bioinformatics analyses strongly suggest that the protein could be translated by programmed −1 ribosomal frameshifting process. Since WARF4 is embedded in the NS4B gene, we rename this novel protein N-NS4B/WARF4. Furthermore, serological analysis shows that N-NS4B/WARF4 is able to elicit antibodies in WNV infected individuals. Conclusions N-NS4B/WARF4 is the second Alternative Reading Frame (ARF) protein that has been demonstrated to be produced following WNV infection and might represent a novel tool for a better characterization of immune response in WNV infected individuals. Further serological as well as functional studies are required to characterize the function of the N-NS4B/WARF4 protein. Since the virus might actually make an extensive use of ARFs, it appears important to investigate the novel six ARF putative proteins of WNV.
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Affiliation(s)
- Giovanni Faggioni
- Histology and Molecular Biology Section, Army Medical and Veterinary Research Center Via Santo Stefano Rotondo, 4 00184 Rome, Italy.
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