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Shankar K, Sorin MN, Sharma H, Skoglund O, Dahmane S, Ter Beek J, Tesfalidet S, Nenzén L, Carlson LA. In vitro reconstitution reveals membrane clustering and RNA recruitment by the enteroviral AAA+ ATPase 2C. PLoS Pathog 2024; 20:e1012388. [PMID: 39102425 PMCID: PMC11326647 DOI: 10.1371/journal.ppat.1012388] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2024] [Revised: 08/15/2024] [Accepted: 07/02/2024] [Indexed: 08/07/2024] Open
Abstract
Enteroviruses are a vast genus of positive-sense RNA viruses that cause diseases ranging from common cold to poliomyelitis and viral myocarditis. They encode a membrane-bound AAA+ ATPase, 2C, that has been suggested to serve several roles in virus replication, e.g. as an RNA helicase and capsid assembly factor. Here, we report the reconstitution of full-length, poliovirus 2C's association with membranes. We show that the N-terminal membrane-binding domain of 2C contains a conserved glycine, which is suggested by structure predictions to divide the domain into two amphipathic helix regions, which we name AH1 and AH2. AH2 is the main mediator of 2C oligomerization, and is necessary and sufficient for its membrane binding. AH1 is the main mediator of a novel function of 2C: clustering of membranes. Cryo-electron tomography reveal that several 2C copies mediate this function by localizing to vesicle-vesicle interfaces. 2C-mediated clustering is partially outcompeted by RNA, suggesting a way by which 2C can switch from an early role in coalescing replication organelles and lipid droplets, to a later role where 2C assists RNA replication and particle assembly. 2C is sufficient to recruit RNA to membranes, with a preference for double-stranded RNA (the replicating form of the viral genome). Finally, the in vitro reconstitution revealed that full-length, membrane-bound 2C has ATPase activity and ATP-independent, single-strand ribonuclease activity, but no detectable helicase activity. Together, this study suggests novel roles for 2C in membrane clustering, RNA membrane recruitment and cleavage, and calls into question a role of 2C as an RNA helicase. The reconstitution of functional, 2C-decorated vesicles provides a platform for further biochemical studies into this protein and its roles in enterovirus replication.
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Affiliation(s)
- Kasturika Shankar
- Department of Medical Biochemistry and Biophysics, Umeå University, Umeå, Sweden
- Wallenberg Centre for Molecular Medicine, Umeå University, Umeå, Sweden
- Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University, Umeå, Sweden
- Umeå Centre for Microbial Research (UCMR), Umeå University, Umeå, Sweden
| | - Marie N Sorin
- Department of Medical Biochemistry and Biophysics, Umeå University, Umeå, Sweden
- Wallenberg Centre for Molecular Medicine, Umeå University, Umeå, Sweden
- Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University, Umeå, Sweden
- Umeå Centre for Microbial Research (UCMR), Umeå University, Umeå, Sweden
| | - Himanshu Sharma
- Department of Medical Biochemistry and Biophysics, Umeå University, Umeå, Sweden
- Wallenberg Centre for Molecular Medicine, Umeå University, Umeå, Sweden
- Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University, Umeå, Sweden
- Umeå Centre for Microbial Research (UCMR), Umeå University, Umeå, Sweden
| | - Oskar Skoglund
- Department of Medical Biochemistry and Biophysics, Umeå University, Umeå, Sweden
- Wallenberg Centre for Molecular Medicine, Umeå University, Umeå, Sweden
- Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University, Umeå, Sweden
- Umeå Centre for Microbial Research (UCMR), Umeå University, Umeå, Sweden
| | - Selma Dahmane
- Department of Medical Biochemistry and Biophysics, Umeå University, Umeå, Sweden
- Wallenberg Centre for Molecular Medicine, Umeå University, Umeå, Sweden
- Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University, Umeå, Sweden
- Umeå Centre for Microbial Research (UCMR), Umeå University, Umeå, Sweden
| | - Josy Ter Beek
- Department of Medical Biochemistry and Biophysics, Umeå University, Umeå, Sweden
- Wallenberg Centre for Molecular Medicine, Umeå University, Umeå, Sweden
- Umeå Centre for Microbial Research (UCMR), Umeå University, Umeå, Sweden
| | | | - Louise Nenzén
- Department of Medical Biochemistry and Biophysics, Umeå University, Umeå, Sweden
- Wallenberg Centre for Molecular Medicine, Umeå University, Umeå, Sweden
- Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University, Umeå, Sweden
- Umeå Centre for Microbial Research (UCMR), Umeå University, Umeå, Sweden
| | - Lars-Anders Carlson
- Department of Medical Biochemistry and Biophysics, Umeå University, Umeå, Sweden
- Wallenberg Centre for Molecular Medicine, Umeå University, Umeå, Sweden
- Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University, Umeå, Sweden
- Umeå Centre for Microbial Research (UCMR), Umeå University, Umeå, Sweden
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2
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Ward JC, Lasecka-Dykes L, Dobson SJ, Gold S, Kingston NJ, Herod MR, King DP, Tuthill TJ, Rowlands DJ, Stonehouse NJ. The dual role of a highly structured RNA (the S fragment) in the replication of foot-and-mouth disease virus. FASEB J 2024; 38:e23822. [PMID: 39072864 DOI: 10.1096/fj.202400500r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2024] [Revised: 06/18/2024] [Accepted: 07/03/2024] [Indexed: 07/30/2024]
Abstract
Secondary and tertiary RNA structures play key roles in genome replication of single-stranded positive sense RNA viruses. Complex, functional structures are particularly abundant in the untranslated regions of picornaviruses, where they are involved in initiation of translation, priming of new strand synthesis and genome circularization. The 5' UTR of foot-and-mouth disease virus (FMDV) is predicted to include a c. 360 nucleotide-long stem-loop, termed the short (S) fragment. This structure is highly conserved and essential for viral replication, but the precise function(s) are unclear. Here, we used selective 2' hydroxyl acetylation analyzed by primer extension (SHAPE) to experimentally determine aspects of the structure, alongside comparative genomic analyses to confirm structure conservation from a wide range of field isolates. To examine its role in virus replication in cell culture, we introduced a series of deletions to the distal and proximal regions of the stem-loop. These truncations affected genome replication in a size-dependent and, in some cases, host cell-dependent manner. Furthermore, during the passage of viruses incorporating the largest tolerated deletion from the proximal region of the S fragment stem-loop, an additional mutation was selected in the viral RNA-dependent RNA polymerase, 3Dpol. These data suggest that the S fragment and 3Dpol interact in the formation of the FMDV replication complex.
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Affiliation(s)
- Joseph C Ward
- School of Molecular and Cellular Biology, Faculty of Biological Sciences and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, UK
| | | | - Samuel J Dobson
- School of Molecular and Cellular Biology, Faculty of Biological Sciences and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, UK
| | | | - Natalie J Kingston
- School of Molecular and Cellular Biology, Faculty of Biological Sciences and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, UK
| | - Morgan R Herod
- School of Molecular and Cellular Biology, Faculty of Biological Sciences and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, UK
| | | | | | - David J Rowlands
- School of Molecular and Cellular Biology, Faculty of Biological Sciences and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, UK
| | - Nicola J Stonehouse
- School of Molecular and Cellular Biology, Faculty of Biological Sciences and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, UK
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3
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Attreed SE, Silva C, Rodriguez-Calzada M, Mogulothu A, Abbott S, Azzinaro P, Canning P, Skidmore L, Nelson J, Knudsen N, Medina GN, de los Santos T, Díaz-San Segundo F. Prophylactic treatment with PEGylated bovine IFNλ3 effectively bridges the gap in vaccine-induced immunity against FMD in cattle. Front Microbiol 2024; 15:1360397. [PMID: 38638908 PMCID: PMC11024232 DOI: 10.3389/fmicb.2024.1360397] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2023] [Accepted: 03/11/2024] [Indexed: 04/20/2024] Open
Abstract
Foot-and-mouth disease (FMD) is a vesicular disease of cloven-hoofed animals with devastating economic implications. The current FMD vaccine, routinely used in enzootic countries, requires at least 7 days to induce protection. However, FMD vaccination is typically not recommended for use in non-enzootic areas, underscoring the need to develop new fast-acting therapies for FMD control during outbreaks. Interferons (IFNs) are among the immune system's first line of defense against viral infections. Bovine type III IFN delivered by a replication defective adenovirus (Ad) vector has effectively blocked FMD in cattle. However, the limited duration of protection-usually only 1-3 days post-treatment (dpt)-diminishes its utility as a field therapeutic. Here, we test whether polyethylene glycosylation (PEGylation) of recombinant bovine IFNλ3 (PEGboIFNλ3) can extend the duration of IFN-induced prevention of FMDV infection in both vaccinated and unvaccinated cattle. We treated groups of heifers with PEGboIFNλ3 alone or in combination with an adenovirus-based FMD O1Manisa vaccine (Adt-O1M) at either 3 or 5 days prior to challenge with homologous wild type FMDV. We found that pre-treatment with PEGboIFNλ3 was highly effective at preventing clinical FMD when administered at either time point, with or without co-administration of Adt-O1M vaccine. PEGboIFNλ3 protein was detectable systemically for >10 days and antiviral activity for 4 days following administration. Furthermore, in combination with Adt-O1M vaccine, we observed a strong induction of FMDV-specific IFNγ+ T cell response, demonstrating its adjuvanticity when co-administered with a vaccine. Our results demonstrate the promise of this modified IFN as a pre-exposure prophylactic therapy for use in emergency outbreak scenarios.
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Affiliation(s)
- Sarah E. Attreed
- Plum Island Animal Disease Center, Plains Area, Agricultural Research Service, U.S. Department of Agriculture, Greenport, NY, United States
| | - Christina Silva
- Plum Island Animal Disease Center, Plains Area, Agricultural Research Service, U.S. Department of Agriculture, Greenport, NY, United States
| | - Monica Rodriguez-Calzada
- Plum Island Animal Disease Center, Plains Area, Agricultural Research Service, U.S. Department of Agriculture, Greenport, NY, United States
- Oak Ridge Institute for Science and Education Plum Island Animal Disease Center Research Participation Program, Oak Ridge, TN, United States
| | - Aishwarya Mogulothu
- Plum Island Animal Disease Center, Plains Area, Agricultural Research Service, U.S. Department of Agriculture, Greenport, NY, United States
- Department of Pathobiology and Veterinary Science, University of Connecticut, Storrs, CT, United States
| | - Sophia Abbott
- Plum Island Animal Disease Center, Plains Area, Agricultural Research Service, U.S. Department of Agriculture, Greenport, NY, United States
- Animal Biosciences and Biotechnology Laboratory, Northeast Area, Agricultural Research Service, U.S. Department of Agriculture, Beltsville, MD, United States
| | - Paul Azzinaro
- Plum Island Animal Disease Center, Plains Area, Agricultural Research Service, U.S. Department of Agriculture, Greenport, NY, United States
| | | | | | - Jay Nelson
- Ambrx Biopharma, Inc., La Jolla, CA, United States
| | - Nick Knudsen
- Ambrx Biopharma, Inc., La Jolla, CA, United States
| | - Gisselle N. Medina
- Plum Island Animal Disease Center, Plains Area, Agricultural Research Service, U.S. Department of Agriculture, Greenport, NY, United States
- National Bio-and Agro-Defense Facility, Plains Area, Agricultural Research Service, U.S. Department of Agriculture, Manhattan, KS, United States
| | - Teresa de los Santos
- Plum Island Animal Disease Center, Plains Area, Agricultural Research Service, U.S. Department of Agriculture, Greenport, NY, United States
| | - Fayna Díaz-San Segundo
- Plum Island Animal Disease Center, Plains Area, Agricultural Research Service, U.S. Department of Agriculture, Greenport, NY, United States
- Office of Biodefense, Research Resources and Translational Research, National Institute of Allergy and Infectious Disease, Rockville, MD, United States
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4
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Yin C, Zhao H, Xia X, Pan Z, Li D, Zhang L. Picornavirus 2C proteins: structure-function relationships and interactions with host factors. Front Cell Infect Microbiol 2024; 14:1347615. [PMID: 38465233 PMCID: PMC10921941 DOI: 10.3389/fcimb.2024.1347615] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Accepted: 02/07/2024] [Indexed: 03/12/2024] Open
Abstract
Picornaviruses, which are positive-stranded, non-enveloped RNA viruses, are known to infect people and animals with a broad spectrum of diseases. Among the nonstructural proteins in picornaviruses, 2C proteins are highly conserved and exhibit multiple structural domains, including amphipathic α-helices, an ATPase structural domain, and a zinc finger structural domain. This review offers a comprehensive overview of the functional structures of picornaviruses' 2C protein. We summarize the mechanisms by which the 2C protein enhances viral replication. 2C protein interacts with various host factors to form the replication complex, ultimately promoting viral replication. We review the mechanisms through which picornaviruses' 2C proteins interact with the NF-κB, RIG-I, MDA5, NOD2, and IFN pathways, contributing to the evasion of the antiviral innate immune response. Additionally, we provide an overview of broad-spectrum antiviral drugs for treating various enterovirus infections, such as guanidine hydrochloride, fluoxetine, and dibucaine derivatives. These drugs may exert their inhibitory effects on viral infections by targeting interactions with 2C proteins. The review underscores the need for further research to elucidate the precise mechanisms of action of 2C proteins and to identify additional host factors for potential therapeutic intervention. Overall, this review contributes to a deeper understanding of picornaviruses and offers insights into the antiviral strategies against these significant viral pathogens.
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Affiliation(s)
- Chunhui Yin
- Department of Clinical Laboratory Medicine, The First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan Hospital, Jinan, Shandong, China
- Department of Pathogen Biology, School of Clinical and Basic Medical Sciences, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, Shandong, China
- Medical Science and Technology Innovation Center, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, Shandong, China
| | - Haomiao Zhao
- Department of Clinical Laboratory Medicine, The First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan Hospital, Jinan, Shandong, China
- Department of Pathogen Biology, School of Clinical and Basic Medical Sciences, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, Shandong, China
- Medical Science and Technology Innovation Center, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, Shandong, China
| | - Xiaoyi Xia
- Department of Pathogen Biology, School of Clinical and Basic Medical Sciences, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, Shandong, China
- Medical Science and Technology Innovation Center, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, Shandong, China
| | - Zhengyang Pan
- Department of Pathogen Biology, School of Clinical and Basic Medical Sciences, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, Shandong, China
- Medical Science and Technology Innovation Center, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, Shandong, China
| | - Daoqun Li
- Department of Pathogen Biology, School of Clinical and Basic Medical Sciences, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, Shandong, China
- Medical Science and Technology Innovation Center, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, Shandong, China
| | - Leiliang Zhang
- Department of Clinical Laboratory Medicine, The First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan Hospital, Jinan, Shandong, China
- Department of Pathogen Biology, School of Clinical and Basic Medical Sciences, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, Shandong, China
- Medical Science and Technology Innovation Center, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, Shandong, China
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5
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He R, Li Y, Bernards MA, Wang A. Manipulation of the Cellular Membrane-Cytoskeleton Network for RNA Virus Replication and Movement in Plants. Viruses 2023; 15:744. [PMID: 36992453 PMCID: PMC10056259 DOI: 10.3390/v15030744] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Revised: 03/10/2023] [Accepted: 03/11/2023] [Indexed: 03/15/2023] Open
Abstract
Viruses infect all cellular life forms and cause various diseases and significant economic losses worldwide. The majority of viruses are positive-sense RNA viruses. A common feature of infection by diverse RNA viruses is to induce the formation of altered membrane structures in infected host cells. Indeed, upon entry into host cells, plant-infecting RNA viruses target preferred organelles of the cellular endomembrane system and remodel organellar membranes to form organelle-like structures for virus genome replication, termed as the viral replication organelle (VRO) or the viral replication complex (VRC). Different viruses may recruit different host factors for membrane modifications. These membrane-enclosed virus-induced replication factories provide an optimum, protective microenvironment to concentrate viral and host components for robust viral replication. Although different viruses prefer specific organelles to build VROs, at least some of them have the ability to exploit alternative organellar membranes for replication. Besides being responsible for viral replication, VROs of some viruses can be mobile to reach plasmodesmata (PD) via the endomembrane system, as well as the cytoskeleton machinery. Viral movement protein (MP) and/or MP-associated viral movement complexes also exploit the endomembrane-cytoskeleton network for trafficking to PD where progeny viruses pass through the cell-wall barrier to enter neighboring cells.
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Affiliation(s)
- Rongrong He
- London Research and Development Centre, Agriculture and Agri-Food Canada, 1391 Sandford St., London, ON N5V 4T3, Canada
- Department of Biology, University of Western Ontario, 1151 Richmond St. N., London, ON N6A 5B7, Canada
| | - Yinzi Li
- London Research and Development Centre, Agriculture and Agri-Food Canada, 1391 Sandford St., London, ON N5V 4T3, Canada
| | - Mark A. Bernards
- Department of Biology, University of Western Ontario, 1151 Richmond St. N., London, ON N6A 5B7, Canada
| | - Aiming Wang
- London Research and Development Centre, Agriculture and Agri-Food Canada, 1391 Sandford St., London, ON N5V 4T3, Canada
- Department of Biology, University of Western Ontario, 1151 Richmond St. N., London, ON N6A 5B7, Canada
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Yeager C, Carter G, Gohara DW, Yennawar NH, Enemark E, Arnold J, Cameron CE. Enteroviral 2C protein is an RNA-stimulated ATPase and uses a two-step mechanism for binding to RNA and ATP. Nucleic Acids Res 2022; 50:11775-11798. [PMID: 36399514 PMCID: PMC9723501 DOI: 10.1093/nar/gkac1054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Revised: 10/16/2022] [Accepted: 10/26/2022] [Indexed: 11/19/2022] Open
Abstract
The enteroviral 2C protein is a therapeutic target, but the absence of a mechanistic framework for this enzyme limits our understanding of inhibitor mechanisms. Here, we use poliovirus 2C and a derivative thereof to elucidate the first biochemical mechanism for this enzyme and confirm the applicability of this mechanism to other members of the enterovirus genus. Our biochemical data are consistent with a dimer forming in solution, binding to RNA, which stimulates ATPase activity by increasing the rate of hydrolysis without impacting affinity for ATP substantially. Both RNA and DNA bind to the same or overlapping site on 2C, driven by the phosphodiester backbone, but only RNA stimulates ATP hydrolysis. We propose that RNA binds to 2C driven by the backbone, with reorientation of the ribose hydroxyls occurring in a second step to form the catalytically competent state. 2C also uses a two-step mechanism for binding to ATP. Initial binding is driven by the α and β phosphates of ATP. In the second step, the adenine base and other substituents of ATP are used to organize the active site for catalysis. These studies provide the first biochemical description of determinants driving specificity and catalytic efficiency of a picornaviral 2C ATPase.
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Affiliation(s)
- Calvin Yeager
- Department of Microbiology & Immunology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Griffin Carter
- Department of Microbiology & Immunology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - David W Gohara
- Department of Biochemistry and Molecular Biology, St. Louis University, St. Louis, MO 63104, USA
| | - Neela H Yennawar
- The Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, PA 16802, USA
| | - Eric J Enemark
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
| | - Jamie J Arnold
- Department of Microbiology & Immunology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Craig E Cameron
- To whom correspondence should be addressed. Tel: +1 919 966 9699; Fax: +1 919 962 8103;
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7
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Sarry M, Vitour D, Zientara S, Bakkali Kassimi L, Blaise-Boisseau S. Foot-and-Mouth Disease Virus: Molecular Interplays with IFN Response and the Importance of the Model. Viruses 2022; 14:v14102129. [PMID: 36298684 PMCID: PMC9610432 DOI: 10.3390/v14102129] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Revised: 09/19/2022] [Accepted: 09/19/2022] [Indexed: 11/18/2022] Open
Abstract
Foot-and-mouth disease (FMD) is a highly contagious viral disease of cloven-hoofed animals with a significant socioeconomic impact. One of the issues related to this disease is the ability of its etiological agent, foot-and-mouth disease virus (FMDV), to persist in the organism of its hosts via underlying mechanisms that remain to be elucidated. The establishment of a virus–host equilibrium via protein–protein interactions could contribute to explaining these phenomena. FMDV has indeed developed numerous strategies to evade the immune response, especially the type I interferon response. Viral proteins target this innate antiviral response at different levels, ranging from blocking the detection of viral RNAs to inhibiting the expression of ISGs. The large diversity of impacts of these interactions must be considered in the light of the in vitro models that have been used to demonstrate them, some being sometimes far from biological systems. In this review, we have therefore listed the interactions between FMDV and the interferon response as exhaustively as possible, focusing on both their biological effect and the study models used.
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Affiliation(s)
- Morgan Sarry
- UMR VIROLOGIE, INRAE, École Nationale Vétérinaire d’Alfort, ANSES Laboratoire de Santé Animale, Université Paris-Est, 94700 Maisons-Alfort, France
- AgroParisTech, 75005 Paris, France
- Correspondence: (M.S.); (S.B.-B.)
| | - Damien Vitour
- UMR VIROLOGIE, INRAE, École Nationale Vétérinaire d’Alfort, ANSES Laboratoire de Santé Animale, Université Paris-Est, 94700 Maisons-Alfort, France
| | - Stephan Zientara
- UMR VIROLOGIE, INRAE, École Nationale Vétérinaire d’Alfort, ANSES Laboratoire de Santé Animale, Université Paris-Est, 94700 Maisons-Alfort, France
| | - Labib Bakkali Kassimi
- UMR VIROLOGIE, INRAE, École Nationale Vétérinaire d’Alfort, ANSES Laboratoire de Santé Animale, Université Paris-Est, 94700 Maisons-Alfort, France
| | - Sandra Blaise-Boisseau
- UMR VIROLOGIE, INRAE, École Nationale Vétérinaire d’Alfort, ANSES Laboratoire de Santé Animale, Université Paris-Est, 94700 Maisons-Alfort, France
- Correspondence: (M.S.); (S.B.-B.)
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8
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Heat Shock Protein 60 Is Involved in Viral Replication Complex Formation and Facilitates Foot and Mouth Virus Replication by Stabilizing Viral Nonstructural Proteins 3A and 2C. mBio 2022; 13:e0143422. [PMID: 36106732 PMCID: PMC9601101 DOI: 10.1128/mbio.01434-22] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The maintenance of viral protein homeostasis depends on the machinery of the infected host cells, giving us an insight into the interplay between host and virus. Accumulating evidence suggests that heat shock protein 60 (HSP60), as one molecular chaperone, is involved in regulating virus infection. However, the role of HSP60 during foot-and-mouth disease virus (FMDV) replication and its specific mechanisms have not been reported. We demonstrate that HSP60 modulates the FMDV life cycle. HSP60 plays a role at the postentry stage of the viral life cycle, including RNA replication and mRNA translation; however, HSP60 does not affect viral replication of Seneca Valley virus (SVA) or encephalomyocarditis virus (EMCV). We found that HSP60 is involved in FMDV replication complex (RC) formation. Furthermore, our results indicate that HSP60 interacts with FMDV nonstructural proteins 3A and 2C, key elements of the viral replication complex. We also show that HSP60 regulates the stability of 3A and 2C via caspase-dependent and autophagy-lysosome-dependent degradation, thereby promoting FMDV RNA synthesis and mRNA translation mediated by the RC. Additionally, we determined that the apical domain of HSP60 is responsible for interacting with 3A and 2C. The N terminus of 3A and ATPase domain of 2C are involved in binding to HSP60. Importantly, HSP60 depletion potently reduced FMDV pathogenicity in infected mice. Altogether, this study demonstrates a specific role of HSP60 in promoting FMDV replication. Furthermore, targeting host HSP60 will help us design the FMDV-specific antiviral drugs.
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Sathanantham P, Zhao W, He G, Murray A, Fenech E, Diaz A, Schuldiner M, Wang X. A conserved viral amphipathic helix governs the replication site-specific membrane association. PLoS Pathog 2022; 18:e1010752. [PMID: 36048900 PMCID: PMC9473614 DOI: 10.1371/journal.ppat.1010752] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Revised: 09/14/2022] [Accepted: 07/19/2022] [Indexed: 11/18/2022] Open
Abstract
Positive-strand RNA viruses assemble their viral replication complexes (VRCs) on specific host organelle membranes, yet it is unclear how viral replication proteins recognize and what motifs or domains in viral replication proteins determine their destinations. We show here that an amphipathic helix, helix B in replication protein 1a of brome mosaic virus (BMV), is necessary for 1a’s localization to the nuclear endoplasmic reticulum (ER) membrane where BMV assembles its VRCs. Helix B is also sufficient to target soluble proteins to the nuclear ER membrane in yeast and plant cells. We further show that an equivalent helix in several plant- and human-infecting viruses of the Alsuviricetes class targets fluorescent proteins to the organelle membranes where they form their VRCs, including ER, vacuole, and Golgi membranes. Our work reveals a conserved helix that governs the localization of VRCs among a group of viruses and points to a possible target for developing broad-spectrum antiviral strategies. Positive-strand RNA viruses [(+)RNA viruses] are the largest viral class that include numerous pathogens causing important diseases in humans, animals, and plants. During their infections, (+)RNA viruses assemble their viral replication complexes (VRCs), where they multiply themselves, at specific organelle membranes. An initial step to form VRCs is to target viral replication proteins to the designated organelle membranes. For brome mosaic virus (BMV), its replication protein 1a is responsible for the VRC formation at the nuclear endoplasmic reticulum (ER) membrane. We show that an amphipathic alpha-helix, helix B, in BMV 1a is necessary for the association of BMV 1a with the nuclear ER membrane and for BMV genome amplification. In addition, Helix B is sufficient to target several soluble proteins to the nuclear ER membrane in yeast and plant cells. BMV belongs to the Alsuviricetes class that includes viruses infecting humans, animals, and plants. We further show that the helix B across members of the Alsuviricetes class is sufficient to target fluorescence proteins to the designated organelle membranes. Our results reveal a conserved feature among a group of viruses in governing the associations with replication site-specific organelle membranes and point to a target to develop broad-spectrum antivirals.
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Affiliation(s)
- Preethi Sathanantham
- School of Plant and Environmental Sciences, Virginia Tech, Blacksburg, Virginia, United States of America
| | - Wenhao Zhao
- School of Plant and Environmental Sciences, Virginia Tech, Blacksburg, Virginia, United States of America
- Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Key Lab of Food Quality and Safety of Jiangsu Province-State Key Laboratory Breeding Base, Nanjing, China
| | - Guijuan He
- School of Plant and Environmental Sciences, Virginia Tech, Blacksburg, Virginia, United States of America
| | - Austin Murray
- School of Plant and Environmental Sciences, Virginia Tech, Blacksburg, Virginia, United States of America
| | - Emma Fenech
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Arturo Diaz
- Department of Biology, La Sierra University, Riverside, California, United States of America
| | - Maya Schuldiner
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Xiaofeng Wang
- School of Plant and Environmental Sciences, Virginia Tech, Blacksburg, Virginia, United States of America
- * E-mail:
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10
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Zhao VY, Rodrigues JV, Lozovsky ER, Hartl DL, Shakhnovich EI. Switching an active site helix in dihydrofolate reductase reveals limits to subdomain modularity. Biophys J 2021; 120:4738-4750. [PMID: 34571014 PMCID: PMC8595743 DOI: 10.1016/j.bpj.2021.09.032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Revised: 09/14/2021] [Accepted: 09/22/2021] [Indexed: 11/23/2022] Open
Abstract
To what degree are individual structural elements within proteins modular such that similar structures from unrelated proteins can be interchanged? We study subdomain modularity by creating 20 chimeras of an enzyme, Escherichia coli dihydrofolate reductase (DHFR), in which a catalytically important, 10-residue α-helical sequence is replaced by α-helical sequences from a diverse set of proteins. The chimeras stably fold but have a range of diminished thermal stabilities and catalytic activities. Evolutionary coupling analysis indicates that the residues of this α-helix are under selection pressure to maintain catalytic activity in DHFR. Reversion to phenylalanine at key position 31 was found to partially restore catalytic activity, which could be explained by evolutionary coupling values. We performed molecular dynamics simulations using replica exchange with solute tempering. Chimeras with low catalytic activity exhibit nonhelical conformations that block the binding site and disrupt the positioning of the catalytically essential residue D27. Simulation observables and in vitro measurements of thermal stability and substrate-binding affinity are strongly correlated. Several E. coli strains with chromosomally integrated chimeric DHFRs can grow, with growth rates that follow predictions from a kinetic flux model that depends on the intracellular abundance and catalytic activity of DHFR. Our findings show that although α-helices are not universally substitutable, the molecular and fitness effects of modular segments can be predicted by the biophysical compatibility of the replacement segment.
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Affiliation(s)
- Victor Y Zhao
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts
| | - João V Rodrigues
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts
| | - Elena R Lozovsky
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts
| | - Daniel L Hartl
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts
| | - Eugene I Shakhnovich
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts.
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11
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Klaitong P, Smith DR. Roles of Non-Structural Protein 4A in Flavivirus Infection. Viruses 2021; 13:v13102077. [PMID: 34696510 PMCID: PMC8538649 DOI: 10.3390/v13102077] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2021] [Revised: 10/11/2021] [Accepted: 10/12/2021] [Indexed: 12/11/2022] Open
Abstract
Infections with viruses in the genus Flavivirus are a worldwide public health problem. These enveloped, positive sense single stranded RNA viruses use a small complement of only 10 encoded proteins and the RNA genome itself to remodel host cells to achieve conditions favoring viral replication. A consequence of the limited viral armamentarium is that each protein exerts multiple cellular effects, in addition to any direct role in viral replication. The viruses encode four non-structural (NS) small transmembrane proteins (NS2A, NS2B, NS4A and NS4B) which collectively remain rather poorly characterized. NS4A is a 16kDa membrane associated protein and recent studies have shown that this protein plays multiple roles, including in membrane remodeling, antagonism of the host cell interferon response, and in the induction of autophagy, in addition to playing a role in viral replication. Perhaps most importantly, NS4A has been implicated as playing a critical role in fetal developmental defects seen as a consequence of Zika virus infection during pregnancy. This review provides a comprehensive overview of the multiple roles of this small but pivotal protein in mediating the pathobiology of flaviviral infections.
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12
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Chen P, Li Z, Cui S. Picornaviral 2C proteins: A unique ATPase family critical in virus replication. Enzymes 2021; 49:235-264. [PMID: 34696834 DOI: 10.1016/bs.enz.2021.06.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
The 2C proteins of Picornaviridae are unique members of AAA+ protein family. Although picornavirus 2C shares many conserved motifs with Super Family 3 DNA helicases, duplex unwinding activity of many 2C proteins remains undetected, and high-resolution structures of 2C hexamers are unavailable. All characterized 2C proteins exhibit ATPase activity, but the purpose of ATP hydrolysis is not fully understood. 2C is highly conserved among picornaviruses and plays crucial roles in nearly all steps of the virus lifecycle. It is therefore considered as an effective target for broad-spectrum antiviral drug development. Crystallographic investigation of enterovirus 2C proteins provide structural details important for the elucidation of 2C function and development of antiviral drugs. This chapter summarizes not only the findings of enzymatic activities, biochemical and structural characterizations of the 2C proteins, but also their role in virus replication, immune evasion and morphogenesis. The linkage between structure and function of the 2C proteins is discussed in detail. Inhibitors targeting the 2C proteins are also summarized to provide an overview of drug development. Finally, we raise several key questions to be addressed in this field and provide future research perspective on this unique class of ATPases.
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Affiliation(s)
- Pu Chen
- Institute of Pathogen Biology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Zhijian Li
- Institute of Pathogen Biology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Sheng Cui
- Institute of Pathogen Biology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China.
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13
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Mahajan S, Sharma GK, Bora K, Pattnaik B. Identification of novel interactions between host and non-structural protein 2C of foot-and-mouth disease virus. J Gen Virol 2021; 102. [PMID: 33729124 DOI: 10.1099/jgv.0.001577] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The 2C protein of foot-and-mouth disease virus (FMDV) is reported to play a critical role in the virus replication complex and modulating the host's immune response. However, the underlying molecular intricacies of subversion of cellular machinery remains poorly understood, thus emphasizing the need to study 2C-host interactions. In this study, we identified the host proteins interacting with the 2C using yeast-two hybrid (Y2H) approach, which is one of the most recognized, high-throughput tools to study protein-protein interactions. The FMDV-2C bait was characterized for auto-activation, toxicity, and expression and was found to be suitable for mating with cDNA library. On preliminary screening a total of 32 interacting host proteins were identified which were reduced to 22 on subsequent confirmation with alternative yeast based assays. Amongst these, NMI/2C interaction has been reported earlier by Wang et al. (2012) and remaining 21 are novel interactions. The Reactome analysis has revealed the role of the identified host proteins in cellular pathways exploited by 2C during FMDV replication. We also confirmed interaction of MARCH7, an E3 ubiquitin ligase with 2C using mammalian two-hybrid system and co-immunoprecipitation. This study leads to the identification of novel 2C interacting host proteins which enhance our understanding of 2C-host interface and may provide checkpoints for development of potential therapeutics against FMDV.
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Affiliation(s)
- Sonalika Mahajan
- Present address: Division of Veterinary Biotechnology, ICAR-Indian Veterinary Research Institute, Izatnagar, Uttar Pradesh, 243122, India.,ICAR-Project Directorate on Foot and Mouth Disease, Mukteswar, Uttarakhand, 263138, India
| | - Gaurav Kumar Sharma
- Present address: Centre for Animal Disease Research and Diagnosis, ICAR-Indian Veterinary Research Institute, Izatnagar, Uttar Pradesh, 243122, India.,ICAR-Project Directorate on Foot and Mouth Disease, Mukteswar, Uttarakhand, 263138, India
| | - Kavita Bora
- ICAR-Project Directorate on Foot and Mouth Disease, Mukteswar, Uttarakhand, 263138, India
| | - Bramhadev Pattnaik
- ICAR-Project Directorate on Foot and Mouth Disease, Mukteswar, Uttarakhand, 263138, India
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14
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Varkey J, Zhang J, Kim J, George G, He G, Belov G, Langen R, Wang X. An Amphipathic Alpha-Helix Domain from Poliovirus 2C Protein Tubulate Lipid Vesicles. Viruses 2020; 12:v12121466. [PMID: 33353144 PMCID: PMC7766222 DOI: 10.3390/v12121466] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2020] [Revised: 12/15/2020] [Accepted: 12/15/2020] [Indexed: 02/01/2023] Open
Abstract
Positive-strand RNA viruses universally remodel host intracellular membranes to form membrane-bound viral replication complexes, where viral offspring RNAs are synthesized. In the majority of cases, viral replication proteins are targeted to and play critical roles in the modulation of the designated organelle membranes. Many viral replication proteins do not have transmembrane domains, but contain single or multiple amphipathic alpha-helices. It has been conventionally recognized that these helices serve as an anchor for viral replication protein to be associated with membranes. We report here that a peptide representing the amphipathic α-helix at the N-terminus of the poliovirus 2C protein not only binds to liposomes, but also remodels spherical liposomes into tubules. The membrane remodeling ability of this amphipathic alpha-helix is similar to that recognized in other amphipathic alpha-helices from cellular proteins involved in membrane remodeling, such as BAR domain proteins. Mutations affecting the hydrophobic face of the amphipathic alpha-helix severely compromised membrane remodeling of vesicles with physiologically relevant phospholipid composition. These mutations also affected the ability of poliovirus to form plaques indicative of reduced viral replication, further underscoring the importance of membrane remodeling by the amphipathic alpha-helix in possible relation to the formation of viral replication complexes.
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Affiliation(s)
- Jobin Varkey
- Zilkha Neurogenetic Institute, University of Southern California, Los Angeles, CA 90033, USA; (J.V.); (G.G.)
| | - Jiantao Zhang
- School of Plant and Environmental Sciences, Virginia Tech, Blacksburg, VA 24061, USA; (J.Z.); (G.H.)
| | - Junghyun Kim
- Virginia-Maryland College of Veterinary Medicine, University of Maryland, College Park, MD 20742, USA; (J.K.); (G.B.)
| | - Gincy George
- Zilkha Neurogenetic Institute, University of Southern California, Los Angeles, CA 90033, USA; (J.V.); (G.G.)
| | - Guijuan He
- School of Plant and Environmental Sciences, Virginia Tech, Blacksburg, VA 24061, USA; (J.Z.); (G.H.)
| | - George Belov
- Virginia-Maryland College of Veterinary Medicine, University of Maryland, College Park, MD 20742, USA; (J.K.); (G.B.)
| | - Ralf Langen
- Zilkha Neurogenetic Institute, University of Southern California, Los Angeles, CA 90033, USA; (J.V.); (G.G.)
- Correspondence: (R.L.); (X.W.); Tel.: +1-323-442-1323 (R.L.); +1-540-231-1868 (X.W.)
| | - Xiaofeng Wang
- School of Plant and Environmental Sciences, Virginia Tech, Blacksburg, VA 24061, USA; (J.Z.); (G.H.)
- Correspondence: (R.L.); (X.W.); Tel.: +1-323-442-1323 (R.L.); +1-540-231-1868 (X.W.)
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15
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Yang B, Zhang X, Zhang D, Hou J, Xu G, Sheng C, Choudhury SM, Zhu Z, Li D, Zhang K, Zheng H, Liu X. Molecular Mechanisms of Immune Escape for Foot-and-Mouth Disease Virus. Pathogens 2020; 9:pathogens9090729. [PMID: 32899635 PMCID: PMC7558374 DOI: 10.3390/pathogens9090729] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Revised: 08/19/2020] [Accepted: 09/01/2020] [Indexed: 12/25/2022] Open
Abstract
Foot-and-mouth disease virus (FMDV) causes a highly contagious vesicular disease in cloven-hoofed livestock that results in severe consequences for international trade, posing a great economic threat to agriculture. The FMDV infection antagonizes the host immune responses via different signaling pathways to achieve immune escape. Strategies to escape the cell immune system are key to effective infection and pathogenesis. This review is focused on summarizing the recent advances to understand how the proteins encoded by FMDV antagonize the host innate and adaptive immune responses.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | - Keshan Zhang
- Correspondence: (K.Z.); (H.Z.); Tel.: +86-15214078335 (K.Z.)
| | - Haixue Zheng
- Correspondence: (K.Z.); (H.Z.); Tel.: +86-15214078335 (K.Z.)
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16
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Garcés-Parada T, Arbeláez-Ramírez LF. Caracterización de la proteína no capsidal 3D, del virus de la fiebre aftosa y producción de anticuerpos policlonales. INFECTIO 2019. [DOI: 10.22354/in.v23i4.814] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Las proteínas no capsidales del virus de la fiebre aftosa se utilizan como marcadoras en la evaluación de animales que han estado en contacto con el virus, a diferencia de los inmunizados, ya que la vacuna no debe tener estas proteínas, por lo tanto los animales no deben presentar anticuerpos contra ellas. El objetivo de esta investigación fue la caracterización de la proteína no capsidal 3D y la producción de anticuerpos policlonales in vivo. La proteína se purificó del cultivo de virus inactivo, por cromatografía de intercambio iónico. La elución de los picos fue sometida a electroforesis uni-bidimensional; demostrándose un alto grado de pureza (>90%) en el pico tres, donde se identifico la proteína 3D, por la técnica de MALDI-TOF y electroespray de trampa iónica. La proteína purificada, se inoculó en cabras y el suero hiperinmune fue precipitado y sometido a cromatografía de afinidad para la obtención de inmunoglobulinas; la reacción inmunitaria se confirmó por medio de inmunodifusión y Western blot. El proceso de purificación demostró ser eficiente y útil para la obtención de anticuerpos específicos, los cuales tendrán utilidad en la elaboración de un ensayo inmunoenzimático que mida la pureza de la vacuna frente al contenido de estas proteínas.
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17
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Viral Generated Inter-Organelle Contacts Redirect Lipid Flux for Genome Replication. Cell 2019; 178:275-289.e16. [PMID: 31204099 DOI: 10.1016/j.cell.2019.05.030] [Citation(s) in RCA: 80] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Revised: 12/05/2018] [Accepted: 05/14/2019] [Indexed: 11/24/2022]
Abstract
Positive-stranded RNA viruses extensively remodel host cell architecture to enable viral replication. Here, we examined the poorly understood formation of specialized membrane compartments that are critical sites for the synthesis of the viral genome. We show that the replication compartments (RCs) of enteroviruses are created through novel membrane contact sites that recruit host lipid droplets (LDs) to the RCs. Viral proteins tether the RCs to the LDs and interact with the host lipolysis machinery to enable transfer of fatty acids from LDs, thereby providing lipids essential for RC biogenesis. Inhibiting the formation of the membrane contact sites between LDs and RCs or inhibition of the lipolysis pathway disrupts RC biogenesis and enterovirus replication. Our data illuminate mechanistic and functional aspects of organelle remodeling in viral infection and establish that pharmacological targeting of contact sites linking viral and host compartments is a potential strategy for antiviral development.
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18
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Medina GN, Segundo FDS, Stenfeldt C, Arzt J, de Los Santos T. The Different Tactics of Foot-and-Mouth Disease Virus to Evade Innate Immunity. Front Microbiol 2018; 9:2644. [PMID: 30483224 PMCID: PMC6241212 DOI: 10.3389/fmicb.2018.02644] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Accepted: 10/17/2018] [Indexed: 12/18/2022] Open
Abstract
Like all pathogens, foot-and-mouth disease virus (FMDV) is recognized by the immune system inducing a heightened immune response mainly mediated by type I and type III IFNs. To overcome the strong antiviral response induced by these cytokines, FMDV has evolved many strategies exploiting each region of its small RNA genome. These include: (a) inhibition of IFN induction at the transcriptional and translational level, (b) inhibition of protein trafficking; (c) blockage of specific post-translational modifications in proteins that regulate innate immune signaling; (d) modulation of autophagy; (e) inhibition of stress granule formation; and (f) in vivo modulation of immune cell function. Here, we summarize and discuss FMDV virulence factors and the host immune footprint that characterize infection in cell culture and in the natural hosts.
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Affiliation(s)
- Gisselle N Medina
- Plum Island Animal Disease Center, United States Department of Agriculture, Agricultural Research Service, Orient, NY, United States.,Codagenix Inc., Farmingdale, NY, United States
| | - Fayna Díaz-San Segundo
- Plum Island Animal Disease Center, United States Department of Agriculture, Agricultural Research Service, Orient, NY, United States.,Animal and Plant Health Inspection Service, Plum Island Animal Disease Center, United States Department of Agriculture, Orient, NY, United States
| | - Carolina Stenfeldt
- Plum Island Animal Disease Center, United States Department of Agriculture, Agricultural Research Service, Orient, NY, United States.,Department of Veterinary Population Medicine, University of Minnesota, St. Paul, MN, United States
| | - Jonathan Arzt
- Plum Island Animal Disease Center, United States Department of Agriculture, Agricultural Research Service, Orient, NY, United States
| | - Teresa de Los Santos
- Plum Island Animal Disease Center, United States Department of Agriculture, Agricultural Research Service, Orient, NY, United States
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19
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Gao Y, Sun SQ, Guo HC. Biological function of Foot-and-mouth disease virus non-structural proteins and non-coding elements. Virol J 2016; 13:107. [PMID: 27334704 PMCID: PMC4917953 DOI: 10.1186/s12985-016-0561-z] [Citation(s) in RCA: 74] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Accepted: 06/13/2016] [Indexed: 02/08/2023] Open
Abstract
Foot-and-mouth disease virus (FMDV) represses host translation machinery, blocks protein secretion, and cleaves cellular proteins associated with signal transduction and the innate immune response to infection. Non-structural proteins (NSPs) and non-coding elements (NCEs) of FMDV play a critical role in these biological processes. The FMDV virion consists of capsid and nucleic acid. The virus genome is a positive single stranded RNA and encodes a single long open reading frame (ORF) flanked by a long structured 5ʹ-untranslated region (5ʹ-UTR) and a short 3ʹ-UTR. The ORF is translated into a polypeptide chain and processed into four structural proteins (VP1, VP2, VP3, and VP4), 10 NSPs (Lpro, 2A, 2B, 2C, 3A, 3B1–3, 3Cpro, and 3Dpol), and some cleavage intermediates. In the past decade, an increasing number of studies have begun to focus on the molecular pathogenesis of FMDV NSPs and NCEs. This review collected recent research progress on the biological functions of these NSPs and NCEs on the replication and host cellular regulation of FMDV to understand the molecular mechanism of host–FMDV interactions and provide perspectives for antiviral strategy and development of novel vaccines.
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Affiliation(s)
- Yuan Gao
- State Key Laboratory of Veterinary Etiological Biology and OIE/National Foot and Mouth Disease Reference Laboratory, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu, 730046, China
| | - Shi-Qi Sun
- State Key Laboratory of Veterinary Etiological Biology and OIE/National Foot and Mouth Disease Reference Laboratory, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu, 730046, China
| | - Hui-Chen Guo
- State Key Laboratory of Veterinary Etiological Biology and OIE/National Foot and Mouth Disease Reference Laboratory, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu, 730046, China.
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20
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Beilstein F, Carrière V, Leturque A, Demignot S. Characteristics and functions of lipid droplets and associated proteins in enterocytes. Exp Cell Res 2015; 340:172-9. [PMID: 26431584 DOI: 10.1016/j.yexcr.2015.09.018] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Accepted: 09/26/2015] [Indexed: 01/23/2023]
Abstract
Cytosolic lipid droplets (LDs) are observed in enterocytes of jejunum during lipid absorption. One important function of the intestine is to secrete chylomicrons, which provide dietary lipids throughout the body, from digested lipids in meals. The current hypothesis is that cytosolic LDs in enterocytes constitute a transient pool of stored lipids that provides lipids during interprandial period while lowering chylomicron production during the post-prandial phase. This smoothens the magnitude of peaks of hypertriglyceridemia. Here, we review the composition and functions of lipids and associated proteins of enterocyte LDs, the known physiological functions of LDs as well as the role of LDs in pathological processes in the context of the intestine.
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Affiliation(s)
- Frauke Beilstein
- Sorbonne Universités, UPMC Univ Paris 06, Inserm, Université Paris Descartes, Sorbonne Paris Cité, UMR_S 1138, Centre de recherche des Cordeliers, F-75006 Paris, France; EPHE, Ecole Pratique des Hautes Etudes, Laboratoire de Pharmacologie Cellulaire et Moléculaire, F-75014 Paris, France
| | - Véronique Carrière
- Sorbonne Universités, UPMC Univ Paris 06, Inserm, Université Paris Descartes, Sorbonne Paris Cité, UMR_S 1138, Centre de recherche des Cordeliers, F-75006 Paris, France
| | - Armelle Leturque
- Sorbonne Universités, UPMC Univ Paris 06, Inserm, Université Paris Descartes, Sorbonne Paris Cité, UMR_S 1138, Centre de recherche des Cordeliers, F-75006 Paris, France
| | - Sylvie Demignot
- Sorbonne Universités, UPMC Univ Paris 06, Inserm, Université Paris Descartes, Sorbonne Paris Cité, UMR_S 1138, Centre de recherche des Cordeliers, F-75006 Paris, France; EPHE, Ecole Pratique des Hautes Etudes, Laboratoire de Pharmacologie Cellulaire et Moléculaire, F-75014 Paris, France.
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21
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Han SC, Guo HC, Sun SQ. Three-dimensional structure of foot-and-mouth disease virus and its biological functions. Arch Virol 2014; 160:1-16. [PMID: 25377637 DOI: 10.1007/s00705-014-2278-x] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Accepted: 10/31/2014] [Indexed: 11/26/2022]
Abstract
Foot-and-mouth disease (FMD), an acute, violent, infectious disease of cloven-hoofed animals, remains widespread in most parts of the world. It can lead to a major plague of livestock and an economical catastrophe. Structural studies of FMD virus (FMDV) have greatly contributed to our understanding of the virus life cycle and provided new horizons for the control and eradication of FMDV. To examine host-FMDV interactions and viral pathogenesis from a structural perspective, the structures of viral structural and non-structural proteins are reviewed in the context of their relevance for virus assembly and dissociation, formation of capsid-like particles and virus-receptor complexes, and viral penetration and uncoating. Moreover, possibilities for devising novel antiviral treatments are discussed.
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Affiliation(s)
- Shi-Chong Han
- State Key Laboratory of Veterinary Etiological Biology and OIE/National Foot and Mouth Disease Reference Laboratory, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Xujiaping 1, Lanzhou, 730046, Gansu, People's Republic of China
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22
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Zheng W, Li X, Wang J, Li X, Cao H, Wang Y, Zeng Q, Zheng SJ. A critical role of interferon-induced protein IFP35 in the type I interferon response in cells induced by foot-and-mouth disease virus (FMDV) protein 2C. Arch Virol 2014; 159:2925-35. [DOI: 10.1007/s00705-014-2147-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2014] [Accepted: 06/05/2014] [Indexed: 11/30/2022]
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23
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Wu MJ, Ke PY, Hsu JTA, Yeh CT, Horng JT. Reticulon 3 interacts with NS4B of the hepatitis C virus and negatively regulates viral replication by disrupting NS4B self-interaction. Cell Microbiol 2014; 16:1603-18. [DOI: 10.1111/cmi.12318] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2013] [Revised: 05/14/2014] [Accepted: 05/16/2014] [Indexed: 12/14/2022]
Affiliation(s)
- Ming-Jhan Wu
- Graduate Institute of Biomedical Sciences; Chang Gung University; Taoyuan Taiwan
| | - Po-Yuan Ke
- Graduate Institute of Biomedical Sciences; Chang Gung University; Taoyuan Taiwan
| | - John T.-A. Hsu
- Institute of Biotechnology and Pharmaceutical Research; National Health Research Institutes; Miaoli Taiwan
| | - Chau-Ting Yeh
- Liver Research Center; Chang Gung Memorial Hospital; Taoyuan Taiwan
| | - Jim-Tong Horng
- Graduate Institute of Biomedical Sciences; Chang Gung University; Taoyuan Taiwan
- Research Center for Emerging Viral Infections; College of Medicine; Chang Gung University; Taoyuan Taiwan
- Department of Medical Research; Chang Gung Memorial Hospital; Taoyuan Taiwan
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24
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Hung YF, Valdau O, Schünke S, Stern O, Koenig BW, Willbold D, Hoffmann S. Recombinant production of the amino terminal cytoplasmic region of dengue virus non-structural protein 4A for structural studies. PLoS One 2014; 9:e86482. [PMID: 24466115 PMCID: PMC3900556 DOI: 10.1371/journal.pone.0086482] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2013] [Accepted: 12/09/2013] [Indexed: 01/17/2023] Open
Abstract
Background Dengue virus (DENV) is a mosquito-transmitted positive single strand RNA virus belonging to the Flaviviridae family. DENV causes dengue fever, currently the world's fastest-spreading tropical disease. Severe forms of the disease like dengue hemorrhagic fever and dengue shock syndrome are life-threatening. There is no specific treatment and no anti-DENV vaccines. Our recent data suggests that the amino terminal cytoplasmic region of the dengue virus non-structural protein 4A (NS4A) comprising amino acid residues 1 to 48 forms an amphipathic helix in the presence of membranes. Its amphipathic character was shown to be essential for viral replication. NMR-based structure-function analysis of the NS4A amino terminal region depends on its milligram-scale production and labeling with NMR active isotopes. Methodology/Principal Findings This report describes the optimization of a uniform procedure for the expression and purification of the wild type NS4A(1-48) peptide and a peptide derived from a replication-deficient mutant NS4A(1-48; L6E, M10E) with disrupted amphipathic nature. A codon-optimized, synthetic gene for NS4A(1-48) was expressed as a fusion with a GST-GB1 dual tag in E. coli. Tobacco etch virus (TEV) protease mediated cleavage generated NS4A(1-48) peptides without any artificial overhang. Using the described protocol up to 4 milligrams of the wild type or up to 5 milligrams of the mutant peptide were obtained from a one-liter culture. Isotopic labeling of the peptides was achieved and initial NMR spectra were recorded. Conclusions/Significance Small molecules targeting amphipathic helices in the related Hepatitis C virus were shown to inhibit viral replication, representing a new class of antiviral drugs. These findings highlight the need for an efficient procedure that provides large quantities of the amphipathic helix containing NS4A peptides. The double tag strategy presented in this manuscript answers these needs yielding amounts that are sufficient for comprehensive biophysical and structural studies, which might reveal new drug targets.
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Affiliation(s)
- Yu-Fu Hung
- Institut für Physikalische Biologie, Heinrich-Heine-Universität, Düsseldorf, Germany
| | - Olga Valdau
- Institute of Complex Systems, Structural Biochemistry (ICS-6), Forschungszentrum Jülich, Jülich, Germany
| | - Sven Schünke
- Institute of Complex Systems, Structural Biochemistry (ICS-6), Forschungszentrum Jülich, Jülich, Germany
| | - Omer Stern
- Department Clinical Microbiology and Immunology, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Bernd W. Koenig
- Institute of Complex Systems, Structural Biochemistry (ICS-6), Forschungszentrum Jülich, Jülich, Germany
- Institut für Physikalische Biologie, Heinrich-Heine-Universität, Düsseldorf, Germany
| | - Dieter Willbold
- Institute of Complex Systems, Structural Biochemistry (ICS-6), Forschungszentrum Jülich, Jülich, Germany
- Institut für Physikalische Biologie, Heinrich-Heine-Universität, Düsseldorf, Germany
| | - Silke Hoffmann
- Institute of Complex Systems, Structural Biochemistry (ICS-6), Forschungszentrum Jülich, Jülich, Germany
- * E-mail:
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Strategies for purifying variants of human rhinovirus 14 2C protein. Protein Expr Purif 2013; 95:28-37. [PMID: 24316192 DOI: 10.1016/j.pep.2013.11.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2013] [Revised: 11/14/2013] [Accepted: 11/25/2013] [Indexed: 11/22/2022]
Abstract
The positive strand RNA genome of picornaviruses, including human rhinovirus (HRV), poliovirus (PV) and foot-and-mouth disease virus, is translated immediately into a polyprotein that is cleaved by virally encoded proteinases into 10-13 mature proteins. These include the four proteins required to assemble the viral particle as well as 3D(pol) (the viral RNA polymerase) and 2C, an ATPase and putative helicase. 2C is a protein which is responsible, together with 2B and 3A, for anchoring the replication complexes to membranous structures in the infected cell on which RNA replication takes place. Additionally, expression of 2C and its precursor 2BC in mammalian cells leads to vesicle formation observed in infected cells. 2C is encoded by all picornaviruses; nevertheless, its exact role in viral replication remains unclear. A contributing factor is the absence of structural data for this hydrophobic protein the generation of which has been hampered by an inability to produce soluble and stable material. Here, we compare 2C from several genera and show that the 2C protein has considerable heterogeneity. Using protein structure meta-analysis, we developed models of HRV14 2C that should be useful for mutational analysis. Based on these analyses, we expressed and purified two domains of HRV14 2C using three different protocols and examined the folding by thermal denaturation or (1)H NMR. Both domains were concentrated sufficiently to allow crystal screens or NMR pilot experiments to be performed. This work provides a platform to explore 2C proteins from all picornaviral genera to generate candidates for structural analysis.
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Mahajan S, Mohapatra JK, Pandey LK, Sharma GK, Pattnaik B. Truncated recombinant non-structural protein 2C-based indirect ELISA for FMD sero-surveillance. J Virol Methods 2013; 193:405-14. [PMID: 23850716 DOI: 10.1016/j.jviromet.2013.07.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2013] [Revised: 06/21/2013] [Accepted: 07/01/2013] [Indexed: 12/27/2022]
Abstract
Foot-and-mouth disease (FMD) is a transboundary animal disease caused by foot-and-mouth disease virus. In India, systematic preventive vaccination using inactivated trivalent (O, A and Asia 1) vaccine is the strategy being adopted to control FMD. The use of non-structural protein (NSP)-contaminated inactivated vaccine raises concerns over differentiation of infected and vaccinated animals (DIVA) by NSP based immunoassays. However, 2C being a membrane associated protein usually remain absent in vaccine formulations and thus, anti-2C response is one of the most reliable indicator of the FMDV infection. In this study, 34 amino acids from N-terminus of 2C protein were removed to eliminate membrane-binding amphipathic helicase activity for the expression of recombinant protein in soluble form. Truncated 2C (2Ct) was utilized for development of an indirect ELISA (I-ELISA) for bovine and the developed 2Ct I-ELISA was validated using a panel constituting of serum of naïve, vaccinated and infected animals. The assay was compared with the in-house r3AB3 I-ELISA and the overall concordance was 85.31%. The diagnostic sensitivity and specificity of the 2Ct I-ELISA were 92.9% and 94.0%, respectively. The apparent prevalence of anti-2C antibodies for random bovine samples tested by the developed assay was 23.7%. The developed ELISA will help in augmenting the sensitivity of detection if used in combination with r3AB3 I-ELISA for sero-surveillance.
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Affiliation(s)
- Sonalika Mahajan
- Project Directorate on Foot and Mouth Disease, Indian Council of Agricultural Research, IVRI Campus, Mukteswar 263138, Uttarakhand, India
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Selective serotonin reuptake inhibitor fluoxetine inhibits replication of human enteroviruses B and D by targeting viral protein 2C. Antimicrob Agents Chemother 2013; 57:1952-6. [PMID: 23335743 DOI: 10.1128/aac.02084-12] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Although the genus Enterovirus contains many important human pathogens, there is no licensed drug for either the treatment or the prophylaxis of enterovirus infections. We report that fluoxetine (Prozac)--a selective serotonin reuptake inhibitor--inhibits the replication of human enterovirus B (HEV-B) and HEV-D but does not affect the replication of HEV-A and HEV-C or human rhinovirus A or B. We show that fluoxetine interferes with viral RNA replication, and we identified viral protein 2C as the target of this compound.
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Wang J, Wang Y, Liu J, Ding L, Zhang Q, Li X, Cao H, Tang J, Zheng SJ. A critical role of N-myc and STAT interactor (Nmi) in foot-and-mouth disease virus (FMDV) 2C-induced apoptosis. Virus Res 2012; 170:59-65. [PMID: 22974759 DOI: 10.1016/j.virusres.2012.08.018] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2012] [Revised: 08/26/2012] [Accepted: 08/28/2012] [Indexed: 10/27/2022]
Abstract
Foot-and-mouth disease virus (FMDV) 2C, is one of the most highly-conserved viral proteins among the serotypes of FMDV. However, its effect on host cells is not very clear. Using yeast two-hybrid system and immunoprecipitation approaches, we found that FMDV 2C interacted with the N-myc and STAT interactor (Nmi) protein. When expressed in cells, FMDV 2C is mainly associated with endoplasmic reticulum in the forms of speckles. In the absence of FMDV 2C, Nmi was distributed diffusely in the cytoplasm. However, upon FMDV 2C overexpression Nmi was recruited into FMDV 2C containing speckles where both proteins are co-localized. In addition, FMDV 2C induced apoptosis in BHK-21 cells, which was markedly inhibited by Nmi knockdown, suggesting that Nmi may play a critical role in FMDV 2C-induced apoptosis. These findings may help to further understand the molecular mechanism of pathogenesis of FMDV infection.
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Affiliation(s)
- Jianchang Wang
- State Key Laboratory of Agrobiotechnology, China Agricultural University, Beijing 100193, China
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29
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Foot-and-mouth disease virus nonstructural protein 2C interacts with Beclin1, modulating virus replication. J Virol 2012; 86:12080-90. [PMID: 22933281 DOI: 10.1128/jvi.01610-12] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Foot-and-mouth disease virus (FMDV), the causative agent of foot-and-mouth disease, is an Apthovirus within the Picornaviridae family. Replication of the virus occurs in association with replication complexes that are formed by host cell membrane rearrangements. The largest viral protein in the replication complex, 2C, is thought to have multiple roles during virus replication. However, studies examining the function of FMDV 2C have been rather limited. To better understand the role of 2C in the process of virus replication, we used a yeast two-hybrid approach to identify host proteins that interact with 2C. We report here that cellular Beclin1 is a specific host binding partner for 2C. Beclin1 is a regulator of the autophagy pathway, a metabolic pathway required for efficient FMDV replication. The 2C-Beclin1 interaction was further confirmed by coimmunoprecipitation and confocal microscopy to actually occur in FMDV-infected cells. Overexpression of either Beclin1 or Bcl-2, another important autophagy factor, strongly affects virus yield in cell culture. The fusion of lysosomes to autophagosomes containing viral proteins is not seen during FMDV infection, a process that is stimulated by Beclin1; however, in FMDV-infected cells overexpressing Beclin1 this fusion occurs, suggesting that 2C would bind to Beclin1 to prevent the fusion of lysosomes to autophagosomes, allowing for virus survival. Using reverse genetics, we demonstrate here that modifications to the amino acids in 2C that are critical for interaction with Beclin1 are also critical for virus growth. These results suggest that interaction between FMDV 2C and host protein Beclin1 could be essential for virus replication.
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Subramaniam S, Sanyal A, Mohapatra JK, Hemadri D, Pattnaik B. Comparative complete genome analysis of Indian type A foot-and-mouth disease virus field isolates. Virus Genes 2011; 43:224-33. [PMID: 21604149 DOI: 10.1007/s11262-011-0622-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2010] [Accepted: 05/07/2011] [Indexed: 11/30/2022]
Abstract
Comparative complete genome analysis of 17 serotype A Indian field isolates representing different genotypes and sub-lineages is presented in this report. Overall 79% of amino acids were invariant in the coding region. Chunk deletion of nucleotide was observed in S and L fragment of 5'-UTR. More variability which is comparable to that of capsid coding region was found in L and 3A region. Functional motifs and residues critical for virus biology were conserved most. Polyprotein cleavage sites accepted few changes. Many sites were detected to be under positive selection in L, P1, 2C, 3A, 3C, and 3D region and of which some are functionally important and antigenically critical. Genotype/lineage specific signature residues could be identified which implies evolution under different selection pressure. Transmembrane domain could be predicted in 2B, 2C, 3A, and 3C proteins in agreement with their membrane binding properties. Phylogenetic analysis at complete coding region placed the isolates in genotype IV, VI, and VII and two broad clusters comprising VP3(59)-deletion and non-deletion group within genotypes VII. The VP3(59)-deletion group has diversified genetically with time giving rise to three lineages. Incongruence in tree topology observed for different non structural protein coding region and UTRs-based phylogeny indicate suspected recombination.
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Affiliation(s)
- Saravanan Subramaniam
- Project Directorate on Foot-and-mouth disease, Mukteswar-Kumaon, Nainital 263138, Uttarakhand, India
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31
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Norder H, De Palma AM, Selisko B, Costenaro L, Papageorgiou N, Arnan C, Coutard B, Lantez V, De Lamballerie X, Baronti C, Solà M, Tan J, Neyts J, Canard B, Coll M, Gorbalenya AE, Hilgenfeld R. Picornavirus non-structural proteins as targets for new anti-virals with broad activity. Antiviral Res 2011; 89:204-18. [DOI: 10.1016/j.antiviral.2010.12.007] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2009] [Revised: 08/23/2010] [Accepted: 12/23/2010] [Indexed: 12/12/2022]
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den Boon JA, Ahlquist P. Organelle-like membrane compartmentalization of positive-strand RNA virus replication factories. Annu Rev Microbiol 2010; 64:241-56. [PMID: 20825348 DOI: 10.1146/annurev.micro.112408.134012] [Citation(s) in RCA: 329] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Positive-strand RNA virus genome replication is invariably associated with extensively rearranged intracellular membranes. Recent biochemical and electron microscopy analyses, including three-dimensional electron microscope tomographic imaging, have fundamentally advanced our understanding of the ultrastructure and function of organelle-like RNA replication factories. Notably, for a range of positive-strand RNA viruses embodying many major differences, independent studies have revealed multiple common principles. These principles include that RNA replication often occurs inside numerous virus-induced vesicles invaginated or otherwise elaborated from a continuous, often endoplasmic reticulum-derived membrane network. Where analyzed, each such vesicle typically contains only one or a few genome replication intermediates in conjunction with many copies of viral nonstructural proteins. In addition, these genome replication compartments often are closely associated with sites of virion assembly and budding. Our understanding of these complexes is growing, providing substantial new insights into the organization, coordination, and potential control of crucial processes in virus replication.
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Affiliation(s)
- Johan A den Boon
- Institute for Molecular Virology, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA.
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33
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Abstract
Many viruses that replicate in the cytoplasm compartmentalize their genome replication and transcription in organelle-like structures that enhance replication efficiency and protection from host defenses. In particular, recent studies with diverse positive-strand RNA viruses have further elucidated the ultrastructure of membrane-bound RNA replication complexes and how these complexes function in close coordination with virion assembly and budding. The structure, function, and assembly of some positive-strand RNA virus replication complexes have parallels and potential evolutionary links with the replicative cores of double-strand RNA virus and retrovirus virions and more general similarities with the replication factories of cytoplasmic DNA viruses.
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Direct interaction between two viral proteins, the nonstructural protein 2C and the capsid protein VP3, is required for enterovirus morphogenesis. PLoS Pathog 2010; 6:e1001066. [PMID: 20865167 PMCID: PMC2928791 DOI: 10.1371/journal.ppat.1001066] [Citation(s) in RCA: 101] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2010] [Accepted: 07/26/2010] [Indexed: 12/27/2022] Open
Abstract
In spite of decades-long studies, the mechanism of morphogenesis of plus-stranded RNA viruses belonging to the genus Enterovirus of Picornaviridae, including poliovirus (PV), is not understood. Numerous attempts to identify an RNA encapsidation signal have failed. Genetic studies, however, have implicated a role of the non-structural protein 2C(ATPase) in the formation of poliovirus particles. Here we report a novel mechanism in which protein-protein interaction is sufficient to explain the specificity in PV encapsidation. Making use of a novel "reporter virus", we show that a quasi-infectious chimera consisting of the capsid precursor of C-cluster coxsackie virus 20 (C-CAV20) and the nonstructural proteins of the closely related PV translated and replicated its genome with wild type kinetics, whereas encapsidation was blocked. On blind passages, encapsidation of the chimera was rescued by a single mutation either in capsid protein VP3 of CAV20 or in 2C(ATPase) of PV. Whereas each of the single-mutation variants expressed severe proliferation phenotypes, engineering both mutations into the chimera yielded a virus encapsidating with wild type kinetics. Biochemical analyses provided strong evidence for a direct interaction between 2C(ATPase) and VP3 of PV and CAV20. Chimeras of other C-CAVs (CAV20/CAV21 or CAV18/CAV20) were blocked in encapsidation (no virus after blind passages) but could be rescued if the capsid and 2C(ATPase) coding regions originated from the same virus. Our novel mechanism explains the specificity of encapsidation without apparent involvement of an RNA signal by considering that (i) genome replication is known to be stringently linked to translation, (ii) morphogenesis is known to be stringently linked to genome replication, (iii) newly synthesized 2C(ATPase) is an essential component of the replication complex, and (iv) 2C(ATPase) has specific affinity to capsid protein(s). These conditions lead to morphogenesis at the site where newly synthesized genomes emerge from the replication complex.
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35
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Sweeney TR, Cisnetto V, Bose D, Bailey M, Wilson JR, Zhang X, Belsham GJ, Curry S. Foot-and-mouth disease virus 2C is a hexameric AAA+ protein with a coordinated ATP hydrolysis mechanism. J Biol Chem 2010; 285:24347-59. [PMID: 20507978 PMCID: PMC2915670 DOI: 10.1074/jbc.m110.129940] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Foot-and-mouth disease virus (FMDV), a positive sense, single-stranded RNA virus, causes a highly contagious disease in cloven-hoofed livestock. Like other picornaviruses, FMDV has a conserved 2C protein assigned to the superfamily 3 helicases a group of AAA+ ATPases that has a predicted N-terminal membrane-binding amphipathic helix attached to the main ATPase domain. In infected cells, 2C is involved in the formation of membrane vesicles, where it co-localizes with viral RNA replication complexes, but its precise role in virus replication has not been elucidated. We show here that deletion of the predicted N-terminal amphipathic helix enables overexpression in Escherichia coli of a highly soluble truncated protein, 2C(34–318), that has ATPase and RNA binding activity. ATPase activity was abrogated by point mutations in the Walker A (K116A) and B (D160A) motifs and Motif C (N207A) in the active site. Unliganded 2C(34–318) exhibits concentration-dependent self-association to yield oligomeric forms, the largest of which is tetrameric. Strikingly, in the presence of ATP and RNA, FMDV 2C(34–318) containing the N207A mutation, which binds but does not hydrolyze ATP, was found to oligomerize specifically into hexamers. Visualization of FMDV 2C-ATP-RNA complexes by negative stain electron microscopy revealed hexameric ring structures with 6-fold symmetry that are characteristic of AAA+ ATPases. ATPase assays performed by mixing purified active and inactive 2C(34–318) subunits revealed a coordinated mechanism of ATP hydrolysis. Our results provide new insights into the structure and mechanism of picornavirus 2C proteins that will facilitate new investigations of their roles in infection.
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Affiliation(s)
- Trevor R Sweeney
- Biophysics Section, Blackett Laboratory, Division of Cell and Molecular Biology, Imperial College London, London SW7 2AZ, United Kingdom
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Teterina NL, Levenson EA, Ehrenfeld E. Viable polioviruses that encode 2A proteins with fluorescent protein tags. J Virol 2010; 84:1477-88. [PMID: 19939919 PMCID: PMC2812313 DOI: 10.1128/jvi.01578-09] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2009] [Accepted: 11/12/2009] [Indexed: 11/20/2022] Open
Abstract
The 2A proteins of the Picornaviridae enterovirus genus are small cysteine proteinases that catalyze essential cleavages in the viral polyprotein in cis and in several cellular proteins in trans. In addition, 2A has been implicated in the process of viral RNA replication, independent of its protease functions. We have generated viable polioviruses that encode 2A proteins containing fluorescent protein tag insertions at either of two sites in the 2A protein structure. Viruses containing an insertion of Discosoma sp. red fluorescent protein (DsRed) after residue 144 of 2A, near the C terminus, produced plaques only slightly smaller than wild-type (wt) virus. The polyprotein harboring the 2A-DsRed fusion protein was efficiently and accurately cleaved; fluorescent 2A proteinase retained protease activity in trans and supported translation and replication of viral RNA, both in vitro and in infected cells. Intracellular membrane reorganization to support viral RNA synthesis was indistinguishable from that induced by wt virus. Infected cells exhibited strong red fluorescence from expression of the 2A-DsRed fusion protein, and the progeny virus was stable for three to four passages, after which deletions within the DsRed coding sequence began to accumulate. Confocal microscopic imaging and analysis revealed a portion of 2A-DsRed in punctate foci concentrated in the perinuclear region that colocalized with replication protein 2C. The majority of 2A, however, was associated with an extensive structural matrix throughout the cytoplasm and was not released from infected cells permeabilized with digitonin.
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Affiliation(s)
- Natalya L. Teterina
- Laboratory of Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892
| | - Eric A. Levenson
- Laboratory of Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892
| | - Ellie Ehrenfeld
- Laboratory of Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892
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Ishikawa K, Sasaki J, Taniguchi K. Overall linkage map of the nonstructural proteins of Aichi virus. Virus Res 2009; 147:77-84. [PMID: 19879907 DOI: 10.1016/j.virusres.2009.10.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2009] [Revised: 10/08/2009] [Accepted: 10/17/2009] [Indexed: 11/16/2022]
Abstract
Aichi virus (AiV), which is associated with acute gastroenteritis in humans, is a member of the genus Kobuvirus of the family Picornaviridae. Picornavirus genome replication occurs in replication complexes that include viral nonstructural proteins, host proteins and viral RNA. In poliovirus, all nonstructural proteins are found in the replication complexes, suggesting the ability of the viral nonstructural proteins to interact with each other. In this study, we examined the interactions between the AiV nonstructural proteins using a mammalian two-hybrid system. The results showed that all of the tested proteins could interact with more than one protein. We observed homodimerization of five proteins, bidirectional heterodimerization of six protein pairs, and unidirectional heterodimerization of eighteen protein pairs. Among the interactions detected in this study, the 2A-2BC, 2A-2BC, 2A-2C, 2BC-3CD, 2BC-3C, 2C-3C, 2C-3CD and 3AB-3C interactions have not been observed in the previous two-hybrid studies with other picornaviruses. The strongest interaction was observed between 2A and 3CD. AiV 2A has already been shown to be involved in genome replication. Domain mapping of the 2A and 3CD interaction in mammalian two-hybrid analysis revealed that the C-terminal quarter of 2A is not required for the interaction with 3CD.
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Affiliation(s)
- Kumiko Ishikawa
- Department of Virology and Parasitology, Fujita Health University School of Medicine, Dengakugakubo 1-98, Kutsukake-cho, Toyoake, Aichi 470-1192, Japan
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Adams P, Kandiah E, Effantin G, Steven AC, Ehrenfeld E. Poliovirus 2C protein forms homo-oligomeric structures required for ATPase activity. J Biol Chem 2009; 284:22012-22021. [PMID: 19520852 DOI: 10.1074/jbc.m109.031807] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The poliovirus protein 2C plays an essential role in viral RNA replication, although its precise biochemical activities or structural requirements have not been elucidated. The protein has several distinctive properties, including ATPase activity and membrane and RNA binding, that are conserved among orthologs of many positive-strand RNA viruses. Sequence alignments have placed these proteins in the SF3 helicase family, a subset of the AAA+ ATPase superfamily. A feature common to AAA+ proteins is the formation of oligomeric rings that are essential for their catalytic functions. Here we show that a recombinant protein, MBP-2C, in which maltose-binding protein was fused to 2C, formed soluble oligomers and that ATPase activity was restricted to oligomer-containing fractions from gel-filtration chromatography. The active fraction was visualized by negative-staining electron microscopy as ring-like particles composed of 5-8 protomers. This conclusion was confirmed by mass measurements obtained by scanning transmission electron microscopy. Mutation of amino acid residues in the 2C nucleotide-binding domain demonstrated that loss of the ability to bind or hydrolyze ATP did not affect oligomerization. Co-expression of active MBP-2C and inactive mutant proteins generated mixed oligomers that exhibited little ATPase activity, suggesting that incorporation of inactive subunits eliminates the function of the entire particle. Finally, deletion of the N-terminal 38 amino acids blocked oligomerization of the fusion protein and eliminated ATPase activity, despite retention of an unaltered nucleotide-binding domain.
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Affiliation(s)
| | | | - Grégory Effantin
- NIAMS, National Institutes of Health, Bethesda, Maryland 20892-8011
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Abstract
Plus-stranded RNA viruses induce large membrane structures that might support the replication of their genomes. Similarly, cytoplasmic replication of poxviruses (large DNA viruses) occurs in associated membranes. These membranes originate from the endoplasmic reticulum (ER) or endosomes. Membrane vesicles that support viral replication are induced by a number of RNA viruses. Similarly, the poxvirus replication site is surrounded by a double-membraned cisterna that is derived from the ER. Analogies to autophagy have been proposed since the finding that autophagy cellular processes involve the formation of double-membrane vesicles. However, molecular evidence to support this hypothesis is lacking. Membrane association of the viral replication complex is mediated by the presence of one or more viral proteins that contain sequences which associate with, or integrate into, membranes. Replication-competent membranes might contain viral or cellular proteins that contain amphipathic helices, which could mediate the membrane bending that is required to form spherical vesicles. Whereas poxvirus DNA replication occurs inside the ER-enclosed site, for most RNA viruses the topology of replication is not clear. Preliminary results for some RNA viruses suggest that their replication could also occur inside double-membrane vesicles. We speculate that cytoplasmic replication might occur inside sites that are 'enwrapped' by an ER-derived cisterna, and that these cisternae are open to the cytoplasm. Thus, RNA and DNA viruses could use a common mechanism for replication that involves membrane wrapping by cellular cisternal membranes. We propose that three-dimensional analyses using high-resolution electron-microscopy techniques could be useful for addressing this issue. High-throughput small-interfering-RNA screens should also shed light on molecular requirements for virus-induced membrane modifications.
Many viruses induce the formation of altered membrane structures upon replication in host cells. This Review examines how viruses modify intracellular membranes, highlights similarities between the structures that are induced by viruses from different families and discusses how these structures could be formed. Viruses are intracellular parasites that use the host cell they infect to produce new infectious progeny. Distinct steps of the virus life cycle occur in association with the cytoskeleton or cytoplasmic membranes, which are often modified during infection. Plus-stranded RNA viruses induce membrane proliferations that support the replication of their genomes. Similarly, cytoplasmic replication of some DNA viruses occurs in association with modified cellular membranes. We describe how viruses modify intracellular membranes, highlight similarities between the structures that are induced by viruses of different families and discuss how these structures could be formed.
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Beske O, Reichelt M, Taylor MP, Kirkegaard K, Andino R. Poliovirus infection blocks ERGIC-to-Golgi trafficking and induces microtubule-dependent disruption of the Golgi complex. J Cell Sci 2007; 120:3207-18. [PMID: 17711878 DOI: 10.1242/jcs.03483] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Cells infected with poliovirus exhibit a rapid inhibition of protein secretion and disruption of the Golgi complex. Neither the precise step at which the virus inhibits protein secretion nor the fate of the Golgi complex during infection has been determined. We find that transport-vesicle exit from the endoplasmic reticulum (ER) and trafficking to the ER-Golgi intermediate compartment (ERGIC) are unaffected in the poliovirus-infected cell. By contrast, poliovirus infection blocks transport from the ERGIC to the Golgi complex. Poliovirus infection also induces fragmentation of the Golgi complex resulting in diffuse distribution of both large and small vesicles throughout the cell. Pre-treatment with nocodazole prevents complete fragmentation, indicating that microtubules are required for poliovirus-induced Golgi dispersion. However, virally induced inhibition of the secretory pathway is not affected by nocodazole, and Golgi dispersion was found to occur during infection with mutant viruses with reduce ability to inhibit protein secretion. We conclude that the dispersion of the Golgi complex is not in itself the cause of inhibition of traffic between the ERGIC and the Golgi. Instead, these phenomena are independent effects of poliovirus infection on the host secretory complex.
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Affiliation(s)
- Oren Beske
- Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA 94143, USA
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41
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Teterina NL, Levenson E, Rinaudo MS, Egger D, Bienz K, Gorbalenya AE, Ehrenfeld E. Evidence for functional protein interactions required for poliovirus RNA replication. J Virol 2007; 80:5327-37. [PMID: 16699013 PMCID: PMC1472133 DOI: 10.1128/jvi.02684-05] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Poliovirus protein 2C contains a predicted N-terminal amphipathic helix that mediates association of the protein with the membranes of the viral RNA replication complex. A chimeric virus that contains sequences encoding the 18-residue core from the orthologous amphipathic helix from human rhinovirus type 14 (HRV14) was constructed. The chimeric virus exhibited defects in viral RNA replication and produced minute plaques on HeLa cell monolayers. Large plaque variants that contained mutations within the 2C-encoding region were generated upon subsequent passage. However, the majority of viruses that emerged with improved growth properties contained no changes in the region encoding 2C. Sequence analysis and reconstruction of genomes with individual mutations revealed changes in 3A or 2B sequences that compensated for the HRV14 amphipathic helix in the polio 2C-containing proteins, implying functional interactions among these proteins during the replication process. Direct binding between these viral proteins was confirmed by mammalian cell two-hybrid analysis.
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Affiliation(s)
- Natalya L Teterina
- Laboratory of Infectious Diseases, National Institute of Allergy and Infectious Diseases/NIH, Bldg. 50, 50 South Drive, Bethesda, MD 20892-8011, USA
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42
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Krogerus C, Samuilova O, Pöyry T, Jokitalo E, Hyypiä T. Intracellular localization and effects of individually expressed human parechovirus 1 non-structural proteins. J Gen Virol 2007; 88:831-841. [PMID: 17325355 DOI: 10.1099/vir.0.82201-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Human parechovirus 1 (HPEV-1) has many unique features compared with other picornaviruses and it has been shown that the replication complex formed during HPEV-1 infection is different from that of other picornaviruses. Here, the intracellular localization and functional effects of individually expressed HPEV-1 non-structural proteins were studied. The 2A and 3D proteins were found diffusely in the cytoplasm and nucleus of the cell. The 3A and 3AB proteins were observed to co-localize with the markers for the Golgi apparatus, whereas 2B co-localized with markers for the endoplasmic reticulum and the 2C and 2BC proteins were observed mainly on the surface of lipid droplets. The 2C protein, which has been implicated in replication-complex formation in enterovirus-infected cells, was not able to induce vesicles similar to those seen in HPEV-1-infected cells when expressed individually. However, in superinfected cells, the fusion protein was able to relocate to the virus replication complexes. Similar to other picornaviruses, HPEV-1 was found to interfere with cellular secretion, but this function could not be ascribed to any of the individually expressed non-structural proteins.
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Affiliation(s)
- Camilla Krogerus
- Haartman Institute, Department of Virology, University of Helsinki, PO Box 21, FIN-00014 Helsinki, Finland
| | - Olga Samuilova
- Haartman Institute, Department of Virology, University of Helsinki, PO Box 21, FIN-00014 Helsinki, Finland
| | - Tuija Pöyry
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1GA, UK
- Haartman Institute, Department of Virology, University of Helsinki, PO Box 21, FIN-00014 Helsinki, Finland
| | - Eija Jokitalo
- Institute of Biotechnology, EM-Unit, University of Helsinki, PO Box 56, FIN-00014 Helsinki, Finland
| | - Timo Hyypiä
- Department of Virology, University of Turku, Kiinamyllynkatu 13, FIN-20520 Turku, Finland
- Haartman Institute, Department of Virology, University of Helsinki, PO Box 21, FIN-00014 Helsinki, Finland
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43
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Brass V, Pal Z, Sapay N, Deléage G, Blum HE, Penin F, Moradpour D. Conserved determinants for membrane association of nonstructural protein 5A from hepatitis C virus and related viruses. J Virol 2006; 81:2745-57. [PMID: 17192310 PMCID: PMC1866014 DOI: 10.1128/jvi.01279-06] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Nonstructural protein 5A (NS5A) is a membrane-associated essential component of the hepatitis C virus (HCV) replication complex. An N-terminal amphipathic alpha helix mediates in-plane membrane association of HCV NS5A and at the same time is likely involved in specific protein-protein interactions required for the assembly of a functional replication complex. The aim of this study was to identify the determinants for membrane association of NS5A from the related GB viruses and pestiviruses. Although primary amino acid sequences differed considerably, putative membrane anchor domains with amphipathic features were predicted in the N-terminal domains of NS5A proteins from these viruses. Confocal laser scanning microscopy, as well as membrane flotation analyses, demonstrated that NS5As from GB virus B (GBV-B), GBV-C, and bovine viral diarrhea virus, the prototype pestivirus, display membrane association characteristics very similar to those of HCV NS5A. The N-terminal 27 to 33 amino acid residues of these NS5A proteins were sufficient for membrane association. Circular dichroism analyses confirmed the capacity of these segments to fold into alpha helices upon association with lipid-like molecules. Despite structural conservation, only very limited exchanges with sequences from related viruses were tolerated in the context of functional HCV RNA replication, suggesting virus-specific interactions of these segments. In conclusion, membrane association of NS5A by an N-terminal amphipathic alpha helix is a feature shared by HCV and related members of the family Flaviviridae. This observation points to conserved roles of the N-terminal amphipathic alpha helices of NS5A in replication complex formation.
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Affiliation(s)
- Volker Brass
- Department of Medicine II, University of Freiburg, D-79106 Freiburg, Germany
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44
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Spuul P, Salonen A, Merits A, Jokitalo E, Kääriäinen L, Ahola T. Role of the amphipathic peptide of Semliki forest virus replicase protein nsP1 in membrane association and virus replication. J Virol 2006; 81:872-83. [PMID: 17093195 PMCID: PMC1797454 DOI: 10.1128/jvi.01785-06] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Semliki Forest virus RNA replication takes place in association with specific cytoplasmic vacuoles, derived from the endosomal apparatus. Of the four virus-encoded replicase proteins, nsP1 serves as the membrane anchor of the replication complex. An amphipathic peptide segment, G245STLYTESRKLLRSWHLPSV264, has been implicated in the membrane binding of nsP1. nsP1 variants with changes within the peptide were studied after protein expression and in the context of virus infection. Proteins with mutations R253E and W259A accumulated in the cytoplasm and were very poorly palmitoylated. The same mutations also drastically affected the localization of the precursor polyprotein P123, and they were lethal when introduced into the virus genome. Mutations R253A and L255A+L256A partially changed the localization of nsP1, and the respective viruses acquired compensatory changes. L255A+L256A only yielded virus encoding L255A+L256V, indicating the importance of a hydrophobic residue in the central 256 position. When fused to green fluorescent protein, the peptide was required in at least two tandem copies to effect a change in localization, but even then the fusion protein was associated with membranes in a nonspecific manner. Thus, the amphipathic peptide is a crucial element for the membrane association of nsP1 and the replication complex. It provides essential affinity for membranes, and other regions of nsP1 also appear to contribute to the localization of the protein.
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Affiliation(s)
- Pirjo Spuul
- Program in Cellular Biotechnology, Institute of Biotechnology, University of Helsinki, Helsinki, Finland
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45
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Heath L, van der Walt E, Varsani A, Martin DP. Recombination patterns in aphthoviruses mirror those found in other picornaviruses. J Virol 2006; 80:11827-32. [PMID: 16971423 PMCID: PMC1642601 DOI: 10.1128/jvi.01100-06] [Citation(s) in RCA: 217] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Foot-and-mouth disease virus (FMDV) is thought to evolve largely through genetic drift driven by the inherently error-prone nature of its RNA polymerase. There is, however, increasing evidence that recombination is an important mechanism in the evolution of these and other related picornoviruses. Here, we use an extensive set of recombination detection methods to identify 86 unique potential recombination events among 125 publicly available FMDV complete genome sequences. The large number of events detected between members of different serotypes suggests that horizontal flow of sequences among the serotypes is relatively common and does not incur severe fitness costs. Interestingly, the distribution of recombination breakpoints was found to be largely nonrandom. Whereas there are clear breakpoint cold spots within the structural genes, two statistically significant hot spots precisely separate these from the nonstructural genes. Very similar breakpoint distributions were found for other picornovirus species in the genera Enterovirus and Teschovirus. Our results suggest that genome regions encoding the structural proteins of both FMDV and other picornaviruses are functionally interchangeable modules, supporting recent proposals that the structural and nonstructural coding regions of the picornaviruses are evolving largely independently of one another.
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Affiliation(s)
- Livio Heath
- Department of Molecular and Cell Biology, Faculty of Science, University of Cape Town, Rondebosch 7701, South Africa
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