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Arita M. An efficient trans complementation system for in vivo replication of defective poliovirus mutants. J Virol 2024; 98:e0052324. [PMID: 38837378 PMCID: PMC11265389 DOI: 10.1128/jvi.00523-24] [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: 03/19/2024] [Accepted: 05/13/2024] [Indexed: 06/07/2024] Open
Abstract
The picornavirus genome encodes a large, single polyprotein that is processed by viral proteases to form an active replication complex. The replication complex is formed with the viral genome, host proteins, and viral proteins that are produced/translated directly from each of the viral genomes (viral proteins provided in cis). Efficient complementation in vivo of replication complex formation by viral proteins provided in trans, thus exogenous or ectopically expressed viral proteins, remains to be demonstrated. Here, we report an efficient trans complementation system for the replication of defective poliovirus (PV) mutants by a viral polyprotein precursor in HEK293 cells. Viral 3AB in the polyprotein, but not 2BC, was processed exclusively in cis. Replication of a defective PV replicon mutant, with a disrupted cleavage site for viral 3Cpro protease between 3Cpro and 3Dpol (3C/D[A/G] mutant) could be rescued by a viral polyprotein provided in trans. Only a defect of 3Dpol activity of the replicon could be rescued in trans; inactivating mutations in 2CATPase/hel, 3B, and 3Cpro of the replicon completely abrogated the trans-rescued replication. An intact N-terminus of the 3Cpro domain of the 3CDpro provided in trans was essential for the trans-active function. By using this trans complementation system, a high-titer defective PV pseudovirus (PVpv) (>107 infectious units per mL) could be produced with the defective mutants, whose replication was completely dependent on trans complementation. This work reveals potential roles of exogenous viral proteins in PV replication and offers insights into protein/protein interaction during picornavirus infection. IMPORTANCE Viral polyprotein processing is an elaborately controlled step by viral proteases encoded in the polyprotein; fully processed proteins and processing intermediates need to be correctly produced for replication, which can be detrimentally affected even by a small modification of the polyprotein. Purified/isolated viral proteins can retain their enzymatic activities required for viral replication, such as protease, helicase, polymerase, etc. However, when these proteins of picornavirus are exogenously provided (provided in trans) to the viral replication complex with a defective viral genome, replication is generally not rescued/complemented, suggesting the importance of viral proteins endogenously provided (provided in cis) to the replication complex. In this study, I discovered that only the viral polymerase activity of poliovirus (PV) (the typical member of picornavirus family) could be efficiently rescued by exogenously expressed viral proteins. The current study reveals potential roles for exogenous viral proteins in viral replication and offers insights into interactions during picornavirus infection.
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Affiliation(s)
- Minetaro Arita
- Department of Virology II, National Institute of Infectious Diseases, Musashimurayama-shi, Tokyo, Japan
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2
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Daniels MG, Werner ME, Li RT, Pascal SM. Exploration of Potential Broad-Spectrum Antiviral Targets in the Enterovirus Replication Element: Identification of Six Distinct 5' Cloverleaves. Viruses 2024; 16:1009. [PMID: 39066172 PMCID: PMC11281424 DOI: 10.3390/v16071009] [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: 05/16/2024] [Revised: 06/18/2024] [Accepted: 06/21/2024] [Indexed: 07/28/2024] Open
Abstract
Enterovirus genomic replication initiates at a predicted RNA cloverleaf (5'CL) at the 5' end of the RNA genome. The 5'CL contains one stem (SA) and three stem-loops (SLB, SLC, SLD). Here, we present an analysis of 5'CL conservation and divergence for 209 human health-related serotypes from the enterovirus genus, including enterovirus and rhinovirus species. Phylogenetic analysis indicates six distinct 5'CL serotypes that only partially correlate with the species definition. Additional findings include that 5'CL sequence conservation is higher between the EV species than between the RV species, the 5'CL of EVA and EVB are nearly identical, and RVC has the lowest 5'CL conservation. Regions of high conservation throughout all species include SA and the loop and nearby bases of SLB, which is consistent with known protein interactions at these sites. In addition to the known protein binding site for the Poly-C binding protein in the loop of SLB, other conserved consecutive cytosines in the stems of SLB and SLC provide additional potential interaction sites that have not yet been explored. Other sites of conservation, including the predicted bulge of SLD and other conserved stem, loop, and junction regions, are more difficult to explain and suggest additional interactions or structural requirements that are not yet fully understood. This more intricate understanding of sequence and structure conservation and variability in the 5'CL may assist in the development of broad-spectrum antivirals against a wide range of enteroviruses, while better defining the range of virus isotypes expected to be affected by a particular antiviral.
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Affiliation(s)
- Morgan G. Daniels
- Department of Chemistry and Biochemistry, Old Dominion University, Norfolk, VA 23529, USA; (M.G.D.); (M.E.W.)
| | - Meagan E. Werner
- Department of Chemistry and Biochemistry, Old Dominion University, Norfolk, VA 23529, USA; (M.G.D.); (M.E.W.)
| | - Rockwell T. Li
- Math and Science Academy, Ocean Lakes High School, Virginia Beach, VA 23454, USA;
| | - Steven M. Pascal
- Department of Chemistry and Biochemistry, Old Dominion University, Norfolk, VA 23529, USA; (M.G.D.); (M.E.W.)
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3
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Kenward C, Vuckovic M, Paetzel M, Strynadka NCJ. Kinetic comparison of all eleven viral polyprotein cleavage site processing events by SARS-CoV-2 main protease using a linked protein FRET platform. J Biol Chem 2024; 300:107367. [PMID: 38750796 PMCID: PMC11209022 DOI: 10.1016/j.jbc.2024.107367] [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: 02/22/2024] [Revised: 04/30/2024] [Accepted: 05/09/2024] [Indexed: 06/13/2024] Open
Abstract
The main protease (Mpro) remains an essential therapeutic target for COVID-19 post infection intervention given its critical role in processing the majority of viral proteins encoded by the genome of severe acute respiratory syndrome related coronavirus 2 (SARS-CoV-2). Upon viral entry, the +ssRNA genome is translated into two long polyproteins (pp1a or the frameshift-dependent pp1ab) containing all the nonstructural proteins (nsps) required by the virus for immune modulation, replication, and ultimately, virion assembly. Included among these nsps is the cysteine protease Mpro (nsp5) which self-excises from the polyprotein, dimerizes, then sequentially cleaves 11 of the 15 cut-site junctions found between each nsp within the polyprotein. Many structures of Mpro (often bound to various small molecule inhibitors or peptides) have been detailed recently, including structures of Mpro bound to each of the polyprotein cleavage sequences, showing that Mpro can accommodate a wide range of targets within its active site. However, to date, kinetic characterization of the interaction of Mpro with each of its native cleavage sequences remains incomplete. Here, we present a robust and cost-effective FRET based system that benefits from a more consistent presentation of the substrate that is also closer in organization to the native polyprotein environment compared to previously reported FRET systems that use chemically modified peptides. Using this system, we were able to show that while each site maintains a similar Michaelis constant, the catalytic efficiency of Mpro varies greatly between cut-site sequences, suggesting a clear preference for the order of nsp processing.
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Affiliation(s)
- Calem Kenward
- Department of Biochemistry and Molecular Biology and Centre for Blood Research, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Marija Vuckovic
- Department of Biochemistry and Molecular Biology and Centre for Blood Research, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Mark Paetzel
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia, Canada.
| | - Natalie C J Strynadka
- Department of Biochemistry and Molecular Biology and Centre for Blood Research, The University of British Columbia, Vancouver, British Columbia, Canada.
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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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Protease-Independent Production of Poliovirus Virus-like Particles in Pichia pastoris: Implications for Efficient Vaccine Development and Insights into Capsid Assembly. Microbiol Spectr 2023; 11:e0430022. [PMID: 36507670 PMCID: PMC9927490 DOI: 10.1128/spectrum.04300-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The production of enterovirus virus-like particles (VLPs) that lack the viral genome have great potential as vaccines for a number of diseases, such as poliomyelitis and hand, foot, and mouth disease. These VLPs can mimic empty capsids, which are antigenically indistinguishable from mature virions, produced naturally during viral infection. Both in infection and in vitro, capsids and VLPs are generated by the cleavage of the P1 precursor protein by a viral protease. Here, using a stabilized poliovirus 1 (PV-1) P1 sequence as an exemplar, we show the production of PV-1 VLPs in Pichia pastoris in the absence of the potentially cytotoxic protease, 3CD, instead using the porcine teschovirus 2A (P2A) peptide sequence to terminate translation between individual capsid proteins. We compare this to protease-dependent production of PV-1 VLPs. Analysis of all permutations of the order of the capsid protein sequences revealed that only VP3 could be tagged with P2A and maintain native antigenicity. Transmission electron microscopy of these VLPs reveals the classic picornaviral icosahedral structure. Furthermore, these particles were thermostable above 37°C, demonstrating their potential as next generation vaccine candidates for PV. Finally, we believe the demonstration that native antigenic VLPs can be produced using protease-independent methods opens the possibility for future enteroviral vaccines to take advantage of recent vaccine technological advances, such as adenovirus-vectored vaccines and mRNA vaccines, circumventing the potential problems of cytotoxicity associated with 3CD, allowing for the production of immunogenic enterovirus VLPs in vivo. IMPORTANCE The widespread use of vaccines has dramatically reduced global incidence of poliovirus infections over a period of several decades and now the wild-type virus is only endemic in Pakistan and Afghanistan. However, current vaccines require the culture of large quantities of replication-competent virus for their manufacture, thus presenting a potential risk of reintroduction into the environment. It is now widely accepted that vaccination will need to be extended posteradication into the foreseeable future to prevent the potentially catastrophic reintroduction of poliovirus into an immunologically naive population. It is, therefore, imperative that novel vaccines are developed which are not dependent on the growth of live virus for their manufacture. We have expressed stabilized virus-like particles in yeast, from constructs that do not require coexpression of the protease. This is an important step in the development of environmentally safe and commercially viable vaccines against polio, which also provides some intriguing insights into the viral assembly process.
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Bouin A, Vu MN, Al-Hakeem A, Tran GP, Nguyen JHC, Semler BL. Enterovirus-Cardiomyocyte Interactions: Impact of Terminally Deleted Genomic RNAs on Viral and Host Functions. J Virol 2023; 97:e0142622. [PMID: 36475766 PMCID: PMC9888282 DOI: 10.1128/jvi.01426-22] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Accepted: 11/21/2022] [Indexed: 12/14/2022] Open
Abstract
Group B enteroviruses, including coxsackievirus B3 (CVB3), can persistently infect cardiac tissue and cause dilated cardiomyopathy. Persistence is linked to 5' terminal deletions of viral genomic RNAs that have been detected together with minor populations of full-length genomes in human infections. In this study, we explored the functions and interactions of the different viral RNA forms found in persistently infected patients and their putative role(s) in pathogenesis. Since enterovirus cardiac pathogenesis is linked to the viral proteinase 2A, we investigated the effect of different terminal genomic RNA deletions on 2A activity. We discovered that 5' terminal deletions in CVB3 genomic RNAs decreased the levels of 2A proteinase activity but could not abrogate it. Using newly generated viral reporters encoding nano-luciferase, we found that 5' terminal deletions resulted in decreased levels of viral protein and RNA synthesis in singly transfected cardiomyocyte cultures. Unexpectedly, when full-length and terminally deleted forms were cotransfected into cardiomyocytes, a cooperative interaction was observed, leading to increased viral RNA and protein production. However, when viral infections were carried out in cells harboring 5' terminally deleted CVB3 RNAs, a decrease in infectious particle production was observed. Our results provide a possible explanation for the necessity of full-length viral genomes during persistent infection, as they would stimulate efficient viral replication compared to that of the deleted genomes alone. To avoid high levels of viral particle production that would trigger cellular immune activation and host cell death, the terminally deleted RNA forms act to limit the production of viral particles, possibly as trans-dominant inhibitors. IMPORTANCE Enteroviruses like coxsackievirus B3 are able to initiate acute infections of cardiac tissue and, in some cases, to establish a long-term persistent infection that can lead to serious disease sequelae, including dilated cardiomyopathy. Previous studies have demonstrated the presence of 5' terminally deleted forms of enterovirus RNAs in heart tissues derived from patients with dilated cardiomyopathy. These deleted RNAs are found in association with very low levels of full-length enterovirus genomic RNAs, an interaction that may facilitate continued persistence while limiting virus particle production. Even in the absence of detectable infectious virus particle production, these deleted viral RNA forms express viral proteinases at levels capable of causing viral pathology. Our studies provide mechanistic insights into how full-length and deleted forms of enterovirus RNA cooperate to stimulate viral protein and RNA synthesis without stimulating infectious viral particle production. They also highlight the importance of targeting enteroviral proteinases to inhibit viral replication while at the same time limiting the long-term pathologies they trigger.
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Affiliation(s)
- Alexis Bouin
- Department of Microbiology & Molecular Genetics, School of Medicine and Center for Virus Research, University of California, Irvine, California, USA
| | - Michelle N. Vu
- Department of Microbiology & Molecular Genetics, School of Medicine and Center for Virus Research, University of California, Irvine, California, USA
| | - Ali Al-Hakeem
- Department of Microbiology & Molecular Genetics, School of Medicine and Center for Virus Research, University of California, Irvine, California, USA
| | - Genevieve P. Tran
- Department of Microbiology & Molecular Genetics, School of Medicine and Center for Virus Research, University of California, Irvine, California, USA
| | - Joseph H. C. Nguyen
- Department of Microbiology & Molecular Genetics, School of Medicine and Center for Virus Research, University of California, Irvine, California, USA
| | - Bert L. Semler
- Department of Microbiology & Molecular Genetics, School of Medicine and Center for Virus Research, University of California, Irvine, California, USA
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Polio and Its Epidemiology. Infect Dis (Lond) 2023. [DOI: 10.1007/978-1-0716-2463-0_839] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/10/2023] Open
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Sherry L, Grehan K, Swanson JJ, Bahar MW, Porta C, Fry EE, Stuart DI, Rowlands DJ, Stonehouse NJ. Production and Characterisation of Stabilised PV-3 Virus-like Particles Using Pichia pastoris. Viruses 2022; 14:2159. [PMID: 36298714 PMCID: PMC9611624 DOI: 10.3390/v14102159] [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: 08/16/2022] [Revised: 09/21/2022] [Accepted: 09/28/2022] [Indexed: 11/05/2022] Open
Abstract
Following the success of global vaccination programmes using the live-attenuated oral and inactivated poliovirus vaccines (OPV and IPV), wild poliovirus (PV) is now only endemic in Afghanistan and Pakistan. However, the continued use of these vaccines poses potential risks to the eradication of PV. The production of recombinant PV virus-like particles (VLPs), which lack the viral genome offer great potential as next-generation vaccines for the post-polio world. We have previously reported production of PV VLPs using Pichia pastoris, however, these VLPs were in the non-native conformation (C Ag), which would not produce effective protection against PV. Here, we build on this work and show that it is possible to produce wt PV-3 and thermally stabilised PV-3 (referred to as PV-3 SC8) VLPs in the native conformation (D Ag) using Pichia pastoris. We show that the PV-3 SC8 VLPs provide a much-improved D:C antigen ratio as compared to wt PV-3, whilst exhibiting greater thermostability than the current IPV vaccine. Finally, we determine the cryo-EM structure of the yeast-derived PV-3 SC8 VLPs and compare this to previously published PV-3 D Ag structures, highlighting the similarities between these recombinantly expressed VLPs and the infectious virus, further emphasising their potential as a next-generation vaccine candidate for PV.
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Affiliation(s)
- Lee Sherry
- School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Keith Grehan
- School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Jessica J. Swanson
- School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Mohammad W. Bahar
- Division of Structural Biology, University of Oxford, The Henry Wellcome Building for Genomic Medicine, Headington, Oxford OX3 7BN, UK
| | - Claudine Porta
- Division of Structural Biology, University of Oxford, The Henry Wellcome Building for Genomic Medicine, Headington, Oxford OX3 7BN, UK
| | - Elizabeth E. Fry
- Division of Structural Biology, University of Oxford, The Henry Wellcome Building for Genomic Medicine, Headington, Oxford OX3 7BN, UK
| | - David I. Stuart
- Division of Structural Biology, University of Oxford, The Henry Wellcome Building for Genomic Medicine, Headington, Oxford OX3 7BN, UK
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot OX11 0DE, UK
| | - David J. Rowlands
- School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Nicola J. Stonehouse
- School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
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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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Jackson T, Belsham GJ. Picornaviruses: A View from 3A. Viruses 2021; 13:v13030456. [PMID: 33799649 PMCID: PMC7999760 DOI: 10.3390/v13030456] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Revised: 03/08/2021] [Accepted: 03/09/2021] [Indexed: 12/14/2022] Open
Abstract
Picornaviruses are comprised of a positive-sense RNA genome surrounded by a protein shell (or capsid). They are ubiquitous in vertebrates and cause a wide range of important human and animal diseases. The genome encodes a single large polyprotein that is processed to structural (capsid) and non-structural proteins. The non-structural proteins have key functions within the viral replication complex. Some, such as 3Dpol (the RNA dependent RNA polymerase) have conserved functions and participate directly in replicating the viral genome, whereas others, such as 3A, have accessory roles. The 3A proteins are highly divergent across the Picornaviridae and have specific roles both within and outside of the replication complex, which differ between the different genera. These roles include subverting host proteins to generate replication organelles and inhibition of cellular functions (such as protein secretion) to influence virus replication efficiency and the host response to infection. In addition, 3A proteins are associated with the determination of host range. However, recent observations have challenged some of the roles assigned to 3A and suggest that other viral proteins may carry them out. In this review, we revisit the roles of 3A in the picornavirus life cycle. The 3AB precursor and mature 3A have distinct functions during viral replication and, therefore, we have also included discussion of some of the roles assigned to 3AB.
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Affiliation(s)
- Terry Jackson
- The Pirbright Institute, Pirbright, Woking, Surrey GU24 0NF, UK;
| | - Graham J. Belsham
- Department of Veterinary and Animal Sciences, University of Copenhagen, 1870 Frederiksberg, Denmark
- Correspondence:
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Processing of the SARS-CoV pp1a/ab nsp7-10 region. Biochem J 2020; 477:1009-1019. [PMID: 32083638 PMCID: PMC7078746 DOI: 10.1042/bcj20200029] [Citation(s) in RCA: 79] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Revised: 02/19/2020] [Accepted: 02/21/2020] [Indexed: 12/14/2022]
Abstract
Severe acute respiratory syndrome coronavirus is the causative agent of a respiratory disease with a high case fatality rate. During the formation of the coronaviral replication/transcription complex, essential steps include processing of the conserved polyprotein nsp7-10 region by the main protease Mpro and subsequent complex formation of the released nsp's. Here, we analyzed processing of the coronavirus nsp7-10 region using native mass spectrometry showing consumption of substrate, rise and fall of intermediate products and complexation. Importantly, there is a clear order of cleavage efficiencies, which is influenced by the polyprotein tertiary structure. Furthermore, the predominant product is an nsp7+8(2 : 2) hetero-tetramer with nsp8 scaffold. In conclusion, native MS, opposed to other methods, can expose the processing dynamics of viral polyproteins and the landscape of protein interactions in one set of experiments. Thereby, new insights into protein interactions, essential for generation of viral progeny, were provided, with relevance for development of antivirals.
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12
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Structural Biology of the Enterovirus Replication-Linked 5'-Cloverleaf RNA and Associated Virus Proteins. Microbiol Mol Biol Rev 2020; 84:84/2/e00062-19. [PMID: 32188627 DOI: 10.1128/mmbr.00062-19] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Although enteroviruses are associated with a wide variety of diseases and conditions, their mode of replication is well conserved. Their genome is carried as a single, positive-sense RNA strand. At the 5' end of the strand is an approximately 90-nucleotide self-complementary region called the 5' cloverleaf, or the oriL. This noncoding region serves as a platform upon which host and virus proteins, including the 3B, 3C, and 3D virus proteins, assemble in order to initiate replication of a negative-sense RNA strand. The negative strand in turn serves as a template for synthesis of multiple positive-sense RNA strands. Building on structural studies of individual RNA stem-loops, the structure of the intact 5' cloverleaf from rhinovirus has recently been determined via nuclear magnetic resonance/small-angle X-ray scattering (NMR/SAXS)-based methods, while structures have also been determined for enterovirus 3A, 3B, 3C, and 3D proteins. Analysis of these structures, together with structural and modeling studies of interactions between host and virus proteins and RNA, has begun to provide insight into the enterovirus replication mechanism and the potential to inhibit replication by blocking these interactions.
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Hassine IH, Gharbi J, Hamrita B, Almalki MA, Rodríguez JF, Ben M'hadheb M. Characterization of Coxsackievirus B4 virus-like particles VLP produced by the recombinant baculovirus-insect cell system expressing the major capsid protein. Mol Biol Rep 2020; 47:2835-2843. [PMID: 32240468 DOI: 10.1007/s11033-020-05333-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Accepted: 02/18/2020] [Indexed: 01/17/2023]
Abstract
Coxsackievirus B4 (CV-B4) is suspected to be an environmental factor that has the intrinsic capacity to damage the pancreatic beta cells and therefore causes insulitis and type 1 diabetes (T1D). Although vaccination against CV-B4 could reduce the incidence of this chronic auto-immune disease, there is currently no therapeutic reagent or vaccine in clinical use. By the employment of the Bac-to-Bac® vector system to express the major viral capsid protein, we contributed towards the development of a CV-B4 vaccine by producing CV-B4 virus-like particles (VLPs) from recombinant baculovirus in infected insect cells. In fact Western blot and Immunofluorescence analysis detected the viral protein 1 (VP1) in the cells resulting from the construction of a recombinant bacmid DNA carrying the key immunogenic protein then transfected in the insect cells. Sucrose gradient ultracentrifugation fractions of the infected cell lysates contained the recombinant protein and the electron microscopy demonstrated the presence of VLPs in these sucrose fractions. This study clearly shows for the first time the expression of CVB4 VP1 structure protein alone can form VLPs in the baculovirus-infected insect cell keeping conserved both characteristics and morphology.
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Affiliation(s)
- Ikbel Hadj Hassine
- Unité de Recherche UR17ES30 "Génomique, Biotechnologie et Stratégies Antivirales", Institut Supérieur de Biotechnologie, Université de Monastir, BP74, Avenue Tahar Hadded, 5000, Monastir, Tunisia.,Department of Molecular and Cellular Biology, Centro Nacional de Biotecnología-CSIC, Cantoblanco, 28049, Madrid, Spain
| | - Jawhar Gharbi
- Unité de Recherche UR17ES30 "Génomique, Biotechnologie et Stratégies Antivirales", Institut Supérieur de Biotechnologie, Université de Monastir, BP74, Avenue Tahar Hadded, 5000, Monastir, Tunisia. .,Department of Biological Sciences, College of Science, King Faisal University, P.O. Box 380, Al-Ahsa, 31982, Saudi Arabia.
| | - Bechr Hamrita
- Unité de Recherche UR17ES30 "Génomique, Biotechnologie et Stratégies Antivirales", Institut Supérieur de Biotechnologie, Université de Monastir, BP74, Avenue Tahar Hadded, 5000, Monastir, Tunisia
| | - Mohammed A Almalki
- Department of Biological Sciences, College of Science, King Faisal University, P.O. Box 380, Al-Ahsa, 31982, Saudi Arabia
| | - José Francisco Rodríguez
- Department of Molecular and Cellular Biology, Centro Nacional de Biotecnología-CSIC, Cantoblanco, 28049, Madrid, Spain
| | - Manel Ben M'hadheb
- Unité de Recherche UR17ES30 "Génomique, Biotechnologie et Stratégies Antivirales", Institut Supérieur de Biotechnologie, Université de Monastir, BP74, Avenue Tahar Hadded, 5000, Monastir, Tunisia
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14
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Comparative Molecular Biology Approaches for the Production of Poliovirus Virus-Like Particles Using Pichia pastoris. mSphere 2020; 5:5/2/e00838-19. [PMID: 32161150 PMCID: PMC7067596 DOI: 10.1128/msphere.00838-19] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Although the current poliovirus immunization program has been extremely successful in reducing the number of cases of paralytic polio worldwide, now more cases are caused by vaccine-derived polioviruses than by wild poliovirus. Switching to inactivated poliovirus vaccines will reduce this over time; however, their production requires the growth of large amounts of virus. This biosafety concern can be addressed by producing just the virus capsid. The capsid serves to protect the genetic material, which causes disease when introduced into a cell. Therefore, empty capsids (virus-like particles [VLPs]), which lack the viral RNA genome, are safe both to make and to use. We exploit yeast as a versatile model expression system to produce VLPs, and here we specifically highlight the potential of this system to supply next-generation poliovirus vaccines to secure a polio-free world for the future. For enteroviruses such as poliovirus (PV), empty capsids, which are antigenically indistinguishable from mature virions, are produced naturally during viral infection. The production of such capsids recombinantly, in heterologous systems such as yeast, have great potential as virus-like particle (VLP) vaccine candidates. Here, using PV as an exemplar, we show the production of VLPs in Pichia pastoris by coexpression of the structural precursor protein P1 and the viral protease 3CD. The level of expression of the potentially cytotoxic protease relative to that of the P1 precursor was modulated by three different approaches: expression of the P1 precursor and protease from different transcription units, separation of the P1 and protease proteins using the Thosea asigna virus (TaV) 2A translation interruption sequence, or separation of the P1 and protease-coding sequences by an internal ribosome entry site sequence from Rhopalosiphum padi virus (RhPV). We also investigate the antigenicity of VLPs containing previously characterized mutations when produced in Pichia. Finally, using transmission electron microscopy and two-dimensional classification, we show that Pichia-derived VLPs exhibited the classical icosahedral capsid structure displayed by enteroviruses. IMPORTANCE Although the current poliovirus immunization program has been extremely successful in reducing the number of cases of paralytic polio worldwide, now more cases are caused by vaccine-derived polioviruses than by wild poliovirus. Switching to inactivated poliovirus vaccines will reduce this over time; however, their production requires the growth of large amounts of virus. This biosafety concern can be addressed by producing just the virus capsid. The capsid serves to protect the genetic material, which causes disease when introduced into a cell. Therefore, empty capsids (virus-like particles [VLPs]), which lack the viral RNA genome, are safe both to make and to use. We exploit yeast as a versatile model expression system to produce VLPs, and here we specifically highlight the potential of this system to supply next-generation poliovirus vaccines to secure a polio-free world for the future.
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15
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Mosaheb MM, Dobrikova EY, Brown MC, Yang Y, Cable J, Okada H, Nair SK, Bigner DD, Ashley DM, Gromeier M. Genetically stable poliovirus vectors activate dendritic cells and prime antitumor CD8 T cell immunity. Nat Commun 2020; 11:524. [PMID: 31988324 PMCID: PMC6985231 DOI: 10.1038/s41467-019-13939-z] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Accepted: 12/06/2019] [Indexed: 12/20/2022] Open
Abstract
Viruses naturally engage innate immunity, induce antigen presentation, and mediate CD8 T cell priming against foreign antigens. Polioviruses can provide a context optimal for generating antigen-specific CD8 T cells, as they have natural tropism for dendritic cells, preeminent inducers of CD8 T cell immunity; elicit Th1-promoting inflammation; and lack interference with innate or adaptive immunity. However, notorious genetic instability and underlying neuropathogenicity has hampered poliovirus-based vector applications. Here we devised a strategy based on the polio:rhinovirus chimera PVSRIPO, devoid of viral neuropathogenicity after intracerebral inoculation in human subjects, for stable expression of exogenous antigens. PVSRIPO vectors infect, activate, and induce epitope presentation in DCs in vitro; they recruit and activate DCs with Th1-dominant cytokine profiles at the injection site in vivo. They efficiently prime tumor antigen-specific CD8 T cells in vivo, induce CD8 T cell migration to the tumor site, delay tumor growth and enhance survival in murine tumor models. Experimental PVSRIPO oncolytic virus therapy of glioblastoma has shown long-term efficacy in a subset of patients. Here the authors engineer the virus to enable incorporation of tumor-specific antigens, and show proof-of-principle evidence that this modification increases anti-tumor immunity and extends survival in mice.
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Affiliation(s)
- Mubeen M Mosaheb
- Department of Molecular Genetics & Microbiology, Duke University Medical School, Durham, NC, 27701, USA
| | - Elena Y Dobrikova
- Department of Neurosurgery, Duke University Medical School, Durham, NC, 27701, USA
| | - Michael C Brown
- Department of Neurosurgery, Duke University Medical School, Durham, NC, 27701, USA
| | - Yuanfan Yang
- Department of Pathology, Duke University Medical School, Durham, NC, 27701, USA
| | - Jana Cable
- Department of Molecular Genetics & Microbiology, Duke University Medical School, Durham, NC, 27701, USA
| | - Hideho Okada
- Parker Institute for Cancer Immunotherapy, University of California at San Francisco, San Francisco, CA, 94129, USA.,Department of Neurological Surgery, University of California at San Francisco, San Francisco, CA, 94129, USA
| | - Smita K Nair
- Department of Surgery, Duke University Medical School, Durham, NC, 27701, USA
| | - Darell D Bigner
- Department of Neurosurgery, Duke University Medical School, Durham, NC, 27701, USA
| | - David M Ashley
- Department of Neurosurgery, Duke University Medical School, Durham, NC, 27701, USA
| | - Matthias Gromeier
- Department of Molecular Genetics & Microbiology, Duke University Medical School, Durham, NC, 27701, USA. .,Department of Neurosurgery, Duke University Medical School, Durham, NC, 27701, USA.
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16
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Host Cell Calpains Can Cleave Structural Proteins from the Enterovirus Polyprotein. Viruses 2019; 11:v11121106. [PMID: 31795245 PMCID: PMC6950447 DOI: 10.3390/v11121106] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Revised: 11/26/2019] [Accepted: 11/26/2019] [Indexed: 12/25/2022] Open
Abstract
Enteroviruses are small RNA viruses that cause diseases with various symptoms ranging from mild to severe. Enterovirus proteins are translated as a single polyprotein, which is cleaved by viral proteases to release capsid and nonstructural proteins. Here, we show that also cellular calpains have a potential role in the processing of the enteroviral polyprotein. Using purified calpains 1 and 2 in an in vitro assay, we show that addition of calpains leads to an increase in the release of VP1 and VP3 capsid proteins from P1 of enterovirus B species, detected by western blotting. This was prevented with a calpain inhibitor and was dependent on optimal calcium concentration, especially for calpain 2. In addition, calpain cleavage at the VP3-VP1 interface was supported by a competition assay using a peptide containing the VP3-VP1 cleavage site. Moreover, a mass spectrometry analysis showed that calpains can cleave this same peptide at the VP3-VP1 interface, the cutting site being two amino acids aside from 3C’s cutting site. Furthermore, we show that calpains cannot cleave between P1 and 2A. In conclusion, we show that cellular proteases, calpains, can cleave structural proteins from enterovirus polyprotein in vitro. Whether they assist polyprotein processing in infected cells remains to be shown.
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17
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Lin JY, Kung YA, Shih SR. Antivirals and vaccines for Enterovirus A71. J Biomed Sci 2019; 26:65. [PMID: 31481071 PMCID: PMC6720414 DOI: 10.1186/s12929-019-0560-7] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Accepted: 08/23/2019] [Indexed: 01/23/2023] Open
Abstract
Enterovirus A71 (EV-A71) is an important emerging virus posing a threat to children under five years old. EV-A71 infection in infants or young children can cause hand-foot-and-mouth disease, herpangina, or severe neurological complications. However, there are still no effective antivirals for treatment of these infections. In this review, we summarize the antiviral compounds developed to date based on various targets of the EV-A71 life cycle. Moreover, development of a vaccine would be the most effective approach to prevent EV-A71 infection. Therefore, we also summarize the development and clinical progress of various candidate EV-A71 vaccines, including inactivated whole virus, recombinant VP1 protein, synthetic peptides, viral-like particles, and live attenuated vaccines.
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Affiliation(s)
- Jing-Yi Lin
- Department of Clinical Laboratory Sciences and Medical Biotechnology, College of Medicine, National Taiwan University, Taipei City, Taiwan
| | - Yu-An Kung
- Research Center for Emerging Viral Infections, College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Shin-Ru Shih
- Research Center for Emerging Viral Infections, College of Medicine, Chang Gung University, Taoyuan, Taiwan. .,Department of Medical Biotechnology and Laboratory Science, College of Medicine, Chang Gung University, Taoyuan, Taiwan. .,Department of Laboratory Medicine, Linkou Chang Gung Memorial Hospital, Taoyuan, Taiwan. .,Research Center for Chinese Herbal Medicine, Research Center for Food and Cosmetic Safety, and Graduate Institute of Health Industry Technology, College of Human Ecology, Chang Gung University of Science and Technology, Taoyuan, Taiwan.
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18
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Characterization of a Non-Canonical Signal Peptidase Cleavage Site in a Replication Protein from Tomato Ringspot Virus. PLoS One 2016; 11:e0162223. [PMID: 27589230 PMCID: PMC5010249 DOI: 10.1371/journal.pone.0162223] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Accepted: 08/18/2016] [Indexed: 11/19/2022] Open
Abstract
The NTB-VPg polyprotein from tomato ringspot virus is an integral membrane replication protein associated with endoplasmic reticulum membranes. A signal peptidase (SPase) cleavage was previously detected in the C-terminal region of NTB-VPg downstream of a 14 amino acid (aa)-long hydrophobic region (termed TM2). However, the exact location of the cleavage site was not determined. Using in vitro translation assays, we show that the SPase cleavage site is conserved in the NTB-VPg protein from various ToRSV isolates, although the rate of cleavage varies from one isolate to another. Systematic site-directed mutagenesis of the NTB-VPg SPase cleavage sites of two ToRSV isolates allowed the identification of sequences that affect cleavage efficiency. We also present evidence that SPase cleavage in the ToRSV-Rasp2 isolate occurs within a GAAGG sequence likely after the AAG (GAAG/G). Mutation of a downstream MAAV sequence to AAAV resulted in SPase cleavage at both the natural GAAG/G and the mutated AAA/V sequences. Given that there is a distance of seven aa between the two cleavage sites, this indicates that there is flexibility in the positioning of the cleavage sites relative to the inner surface of the membrane and the SPase active site. SPase cleavage sites are typically located 3–7 aa downstream of the hydrophobic region. However, the NTB-VPg GAAG/G cleavage site is located 17 aa downstream of the TM2 hydrophobic region, highlighting unusual features of the NTB-VPg SPase cleavage site. A putative 11 aa-long amphipathic helix was identified immediately downstream of the TM2 region and five aa upstream of the GAAG/G cleavage site. Based on these results, we present an updated topology model in which the hydrophobic and amphipathic domains form a long tilted helix or a bent helix in the membrane lipid bilayer, with the downstream cleavage site(s) oriented parallel to the membrane inner surface.
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19
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Coxsackievirus B3 infection induces autophagic flux, and autophagosomes are critical for efficient viral replication. Arch Virol 2016; 161:2197-205. [DOI: 10.1007/s00705-016-2896-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Accepted: 05/13/2016] [Indexed: 10/21/2022]
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20
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Laitinen OH, Svedin E, Kapell S, Nurminen A, Hytönen VP, Flodström-Tullberg M. Enteroviral proteases: structure, host interactions and pathogenicity. Rev Med Virol 2016; 26:251-67. [PMID: 27145174 PMCID: PMC7169145 DOI: 10.1002/rmv.1883] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Revised: 03/22/2016] [Accepted: 03/23/2016] [Indexed: 12/22/2022]
Abstract
Enteroviruses are common human pathogens, and infections are particularly frequent in children. Severe infections can lead to a variety of diseases, including poliomyelitis, aseptic meningitis, myocarditis and neonatal sepsis. Enterovirus infections have also been implicated in asthmatic exacerbations and type 1 diabetes. The large disease spectrum of the closely related enteroviruses may be partially, but not fully, explained by differences in tissue tropism. The molecular mechanisms by which enteroviruses cause disease are poorly understood, but there is increasing evidence that the two enteroviral proteases, 2Apro and 3Cpro, are important mediators of pathology. These proteases perform the post‐translational proteolytic processing of the viral polyprotein, but they also cleave several host‐cell proteins in order to promote the production of new virus particles, as well as to evade the cellular antiviral immune responses. Enterovirus‐associated processing of cellular proteins may also contribute to pathology, as elegantly demonstrated by the 2Apro‐mediated cleavage of dystrophin in cardiomyocytes contributing to Coxsackievirus‐induced cardiomyopathy. It is likely that improved tools to identify targets for these proteases will reveal additional host protein substrates that can be linked to specific enterovirus‐associated diseases. Here, we discuss the function of the enteroviral proteases in the virus replication cycle and review the current knowledge regarding how these proteases modulate the infected cell in order to favour virus replication, including ways to avoid detection by the immune system. We also highlight new possibilities for the identification of protease‐specific cellular targets and thereby a way to discover novel mechanisms contributing to disease. Copyright © 2016 John Wiley & Sons, Ltd.
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Affiliation(s)
- Olli H Laitinen
- BioMediTech, Finland and Fimlab Laboratories, University of Tampere, Tampere, Finland
| | - Emma Svedin
- The Center for Infectious Medicine, Department of Medicine HS, Karolinska Institutet, Stockholm, Sweden
| | - Sebastian Kapell
- The Center for Infectious Medicine, Department of Medicine HS, Karolinska Institutet, Stockholm, Sweden
| | - Anssi Nurminen
- BioMediTech, Finland and Fimlab Laboratories, University of Tampere, Tampere, Finland
| | - Vesa P Hytönen
- BioMediTech, Finland and Fimlab Laboratories, University of Tampere, Tampere, Finland
| | - Malin Flodström-Tullberg
- BioMediTech, Finland and Fimlab Laboratories, University of Tampere, Tampere, Finland.,The Center for Infectious Medicine, Department of Medicine HS, Karolinska Institutet, Stockholm, Sweden
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21
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Schimer J, Pávová M, Anders M, Pachl P, Šácha P, Cígler P, Weber J, Majer P, Řezáčová P, Kräusslich HG, Müller B, Konvalinka J. Triggering HIV polyprotein processing by light using rapid photodegradation of a tight-binding protease inhibitor. Nat Commun 2015; 6:6461. [PMID: 25751579 PMCID: PMC4366505 DOI: 10.1038/ncomms7461] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2014] [Accepted: 01/29/2015] [Indexed: 12/23/2022] Open
Abstract
HIV protease (PR) is required for proteolytic maturation in the late phase of HIV replication and represents a prime therapeutic target. The regulation and kinetics of viral polyprotein processing and maturation are currently not understood in detail. Here we design, synthesize, validate and apply a potent, photodegradable HIV PR inhibitor to achieve synchronized induction of proteolysis. The compound exhibits subnanomolar inhibition in vitro. Its photolabile moiety is released on light irradiation, reducing the inhibitory potential by 4 orders of magnitude. We determine the structure of the PR-inhibitor complex, analyze its photolytic products, and show that the enzymatic activity of inhibited PR can be fully restored on inhibitor photolysis. We also demonstrate that proteolysis of immature HIV particles produced in the presence of the inhibitor can be rapidly triggered by light enabling thus to analyze the timing, regulation and spatial requirements of viral processing in real time. The study of HIV proteolysis during maturation and replication can be difficult since different steps in these processes occur simultaneously. Here, the authors present a photolabile HIV protease inhibitor which can be deactivated by light irradiation, allowing synchronized induction of viral maturation.
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Affiliation(s)
- Jiří Schimer
- 1] Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Gilead Sciences and IOCB Research Center, Flemingovo n.2, 166 10, Prague 6, Czech Republic [2] Department of Biochemistry, Faculty of Science, Charles University in Prague, Hlavova 8, 128 43, Prague 2, Czech Republic
| | - Marcela Pávová
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Gilead Sciences and IOCB Research Center, Flemingovo n.2, 166 10, Prague 6, Czech Republic
| | - Maria Anders
- Department of Infectious Diseases, Virology, University Hospital Heidelberg, Im Neuenheimer Feld 324, 69120 Heidelberg, Germany
| | - Petr Pachl
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Gilead Sciences and IOCB Research Center, Flemingovo n.2, 166 10, Prague 6, Czech Republic
| | - Pavel Šácha
- 1] Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Gilead Sciences and IOCB Research Center, Flemingovo n.2, 166 10, Prague 6, Czech Republic [2] Department of Biochemistry, Faculty of Science, Charles University in Prague, Hlavova 8, 128 43, Prague 2, Czech Republic
| | - Petr Cígler
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Gilead Sciences and IOCB Research Center, Flemingovo n.2, 166 10, Prague 6, Czech Republic
| | - Jan Weber
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Gilead Sciences and IOCB Research Center, Flemingovo n.2, 166 10, Prague 6, Czech Republic
| | - Pavel Majer
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Gilead Sciences and IOCB Research Center, Flemingovo n.2, 166 10, Prague 6, Czech Republic
| | - Pavlína Řezáčová
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Gilead Sciences and IOCB Research Center, Flemingovo n.2, 166 10, Prague 6, Czech Republic
| | - Hans-Georg Kräusslich
- 1] Department of Infectious Diseases, Virology, University Hospital Heidelberg, Im Neuenheimer Feld 324, 69120 Heidelberg, Germany [2] Molecular Medicine Partnership Unit, Heidelberg, Germany
| | - Barbara Müller
- 1] Department of Infectious Diseases, Virology, University Hospital Heidelberg, Im Neuenheimer Feld 324, 69120 Heidelberg, Germany [2] Molecular Medicine Partnership Unit, Heidelberg, Germany
| | - Jan Konvalinka
- 1] Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Gilead Sciences and IOCB Research Center, Flemingovo n.2, 166 10, Prague 6, Czech Republic [2] Department of Biochemistry, Faculty of Science, Charles University in Prague, Hlavova 8, 128 43, Prague 2, Czech Republic
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22
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Coxsackievirus B3 VLPs purified by ion exchange chromatography elicit strong immune responses in mice. Antiviral Res 2014; 104:93-101. [DOI: 10.1016/j.antiviral.2014.01.013] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2013] [Revised: 12/20/2013] [Accepted: 01/20/2014] [Indexed: 01/29/2023]
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23
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24
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Schünemann K, Connelly S, Kowalczyk R, Sperry J, Wilson IA, Fraser JD, Brimble MA. A simple solid phase, peptide-based fluorescent assay for the efficient and universal screening of HRV 3C protease inhibitors. Bioorg Med Chem Lett 2012; 22:5018-24. [PMID: 22763202 DOI: 10.1016/j.bmcl.2012.06.015] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2012] [Accepted: 06/06/2012] [Indexed: 11/30/2022]
Abstract
With over a 100 different serotypes, the human rhinovirus (HRV) is the major aetiological agent for the common cold, for which only symptomatic treatment is available. HRV maturation and replication is entirely dependent on the activity of a virally encoded 3C protease that represents an attractive target for the development of therapeutics to treat the common cold. Although a variety of small molecules and peptidomimetics have been found to inhibit HRV 3C protease, no universally compatible assay exists to reliably quantify the activity of the enzyme in vitro. Herein we report the development of a universal and robust solid phase peptide assay that utilizes the full HRV-14 3C protease recognition sequence and the release of 5(6)-carboxyfluorescein to sensitively quantify protease activity. This novel assay overcomes several limitations of existing assays allowing for the simple and efficient analysis of HRV-14 3C protease activity facilitating both high-throughput screening and the accurate kinetic study of HRV-14 3C protease inhibitors.
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Affiliation(s)
- Katrin Schünemann
- School of Chemical Sciences, The University of Auckland, Auckland, New Zealand
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25
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Zhang XN, Song ZG, Jiang T, Shi BS, Hu YW, Yuan ZH. Rupintrivir is a promising candidate for treating severe cases of Enterovirus-71 infection. World J Gastroenterol 2010; 16:201-9. [PMID: 20066739 PMCID: PMC2806558 DOI: 10.3748/wjg.v16.i2.201] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/07/2009] [Revised: 11/08/2009] [Accepted: 11/15/2009] [Indexed: 02/06/2023] Open
Abstract
AIM To evaluate the suitability of rupintrivir against Enterovirus 71 (EV71) induced severe clinical symptoms using computational methods. METHODS The structure of EV71 3C protease was predicted by homology modeling. The binding free energies between rupintrivir and EV71 3C and human rhinovirus 3C protease were computed by molecular dynamics and molecular mechanics Poisson-Boltzmann/surface area and molecular mechanics generalized-born/surface area methods. EV71 3C fragments obtained from clinical samples collected during May to July 2008 in Shanghai were amplified by reverse-transcription and polymerase chain reaction and sequenced. RESULTS We observed that rupintrivir had favorable binding affinity with EV71 3C protease (-10.76 kcal/mol). The variability of the 3C protein sequence in isolates of various outbreaks, including those obtained in our hospital from May to July 2008, were also analyzed to validate the conservation of the drug binding pocket. CONCLUSION Rupintrivir, whose safety profiles had been proved, is an attractive candidate and can be quickly utilized for treating severe EV71 infection.
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26
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Schrauf C, Kirchberger S, Majdic O, Seyerl M, Zlabinger GJ, Stuhlmeier KM, Sachet M, Seipelt J, Stöckl J. The ssRNA genome of human rhinovirus induces a type I IFN response but fails to induce maturation in human monocyte-derived dendritic cells. THE JOURNAL OF IMMUNOLOGY 2009; 183:4440-8. [PMID: 19734213 DOI: 10.4049/jimmunol.0804147] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Dendritic cells (DCs) use pattern recognition receptors to sense invading viruses and triggering of these receptors induces a maturation program. Human rhinoviruses (HRVs) belong to the family of Picornaviridae, which have a single-stranded, coding RNA genome. Because HRV does not replicate in DCs, we used genomic RNA from HRV in this study to analyze the impact of natural occurring viral ssRNA on DC function. We found that transfection of human monocyte-derived DCs with viral ssRNA induced type I IFN production but failed to activate the NF-kappaB pathway in DCs. In line with this observation, the up-regulation of typical maturation markers such as CD83 or the production of the proinflammatory cytokines IL-12p40, IL-6, and TNF-alpha was not detectable. Most importantly, the T cell stimulatory capacity of viral ssRNA-treated DCs was not enhanced and remained at the level of immature DCs. Taken together, our results demonstrate that viral ssRNA efficiently activates the innate defense arm of DCs, whereas it is insufficient to activate the stimulatory capacity of DCs for the adaptive defense responses.
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Affiliation(s)
- Catharina Schrauf
- Institute of Immunology, Medical University of Vienna, Vienna 1090, Austria
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27
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Poliovirus 2A(Pro) increases viral mRNA and polysome stability coordinately in time with cleavage of eIF4G. J Virol 2008; 82:5847-59. [PMID: 18400852 DOI: 10.1128/jvi.01514-07] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Poliovirus (PV) 2A protease (2A(Pro)) cleaves eukaryotic initiation factors 4GI and 4GII (eIF4GI and eIF4GII) within virus-infected cells, effectively halting cap-dependent mRNA translation. PV mRNA, which does not possess a 5' cap, is translated via cap-independent mechanisms within viral protease-modified messenger ribonucleoprotein (mRNP) complexes. In this study, we determined that 2A(Pro) activity was required for viral polysome formation and stability. 2A(Pro) cleaved eIF4GI and eIF4GII as PV polysomes assembled. A 2A(Cys109Ser) (2A(Pro) with a Cys109Ser mutation) protease active site mutation that prevented cleavage of eIF4G coordinately inhibited the de novo formation of viral polysomes, the stability of viral polysomes, and the stability of PV mRNA within polysomes. 2A(Cys109Ser)-associated defects in PV mRNA and polysome stability correlated with defects in PV mRNA translation. 3C(Pro) activity was not required for viral polysome formation or stability. 2A(Pro)-mediated cleavage of eIF4G along with poly(rC) binding protein binding to the 5' terminus of uncapped PV mRNA appear to be concerted mechanisms that allow PV mRNA to form mRNP complexes that evade cellular mRNA degradation machinery.
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Abstract
Hepatitis E virus (HEV) is the aetiological agent of non-HAV enterically transmitted hepatitis. It is the major cause of sporadic as well as epidemic hepatitis, which is no longer confined to Asia and developing countries but has also become a concern of the developed nations. In the Indian subcontinent, it accounts for 30-60% of sporadic hepatitis. It is generally accepted that hepatitis E is mostly self-limited and never progresses to chronicity. It has a higher mortality in pregnant women where the disease condition is accentuated with the development of fulminant liver disease. Currently, no antiviral drug or vaccine is licensed for HEV, although a vaccine candidate is in clinical trials. HEV genome is 7.2kb in size with three open reading frames (ORFs) and 5' and 3' cis acting elements, which have important roles to play in HEV replication and transcription. ORF1 codes for methyl transferase, protease, helicase and replicase; ORF2 codes for the capsid protein and ORF3 for a protein of undefined function. HEV has recently been classified in the genus Hepevirus of the family Hepeviridae. There are four major recognised genotypes with a single known serotype. The absence of a reliable in vitro propagation system is an obstacle to deciphering HEV biology. The genome of HEV has been cloned, sequenced and the infectious nature of these replicons has been established. However, questions related to replication, transcription, virus-host interactions and pathogenesis remain to be answered. This comprehensive review summarises the progress made so far in HEV research, and addresses some of the unanswered questions.
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Affiliation(s)
- Subrat Kumar Panda
- Department of Pathology, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, India.
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Schmidtke M, Knorre C, Blei L, Stelzner A, Birch-Hirschfeld E. Penetration and Antiviral Activity of Coxsackievirus B3 (Cvb3)-Specific Phosphorothioate Oligodeoxynucleotides (Ps-Odn). ACTA ACUST UNITED AC 2006. [DOI: 10.1080/07328319808004686] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- M. Schmidtke
- a Institute of Virology, Friedrich Schiller University , 07745 , Jena , Germany
| | - C. Knorre
- a Institute of Virology, Friedrich Schiller University , 07745 , Jena , Germany
| | - L. Blei
- b Hans-Knöll-Institute for Natural Product Research , 07745 , Jena , Germany
| | - A. Stelzner
- a Institute of Virology, Friedrich Schiller University , 07745 , Jena , Germany
| | - E. Birch-Hirschfeld
- a Institute of Virology, Friedrich Schiller University , 07745 , Jena , Germany
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30
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Murray KE, Barton DJ. Poliovirus CRE-dependent VPg uridylylation is required for positive-strand RNA synthesis but not for negative-strand RNA synthesis. J Virol 2003; 77:4739-50. [PMID: 12663781 PMCID: PMC152113 DOI: 10.1128/jvi.77.8.4739-4750.2003] [Citation(s) in RCA: 112] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The cis-acting replication element (CRE) is a 61-nucleotide stem-loop RNA structure found within the coding sequence of poliovirus protein 2C. Although the CRE is required for viral RNA replication, its precise role(s) in negative- and positive-strand RNA synthesis has not been defined. Adenosine in the loop of the CRE RNA structure functions as the template for the uridylylation of the viral protein VPg. VPgpUpU(OH), the predominant product of CRE-dependent VPg uridylylation, is a putative primer for the poliovirus RNA-dependent RNA polymerase. By examining the sequential synthesis of negative- and positive-strand RNAs within preinitiation RNA replication complexes, we found that mutations that disrupt the structure of the CRE prevent VPg uridylylation and positive-strand RNA synthesis. The CRE mutations that inhibited the synthesis of VPgpUpU(OH), however, did not inhibit negative-strand RNA synthesis. A Y3F mutation in VPg inhibited both VPgpUpU(OH) synthesis and negative-strand RNA synthesis, confirming the critical role of the tyrosine hydroxyl of VPg in VPg uridylylation and negative-strand RNA synthesis. trans-replication experiments demonstrated that the CRE and VPgpUpU(OH) were not required in cis or in trans for poliovirus negative-strand RNA synthesis. Because these results are inconsistent with existing models of poliovirus RNA replication, we propose a new four-step model that explains the roles of VPg, the CRE, and VPgpUpU(OH) in the asymmetric replication of poliovirus RNA.
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Affiliation(s)
- Kenneth E Murray
- Department of Microbiology, University of Colorado Health Sciences Center, Denver, Colorado 80262, USA
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31
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Henke A, Launhardt H, Klement K, Stelzner A, Zell R, Munder T. Apoptosis in coxsackievirus B3-caused diseases: interaction between the capsid protein VP2 and the proapoptotic protein siva. J Virol 2000; 74:4284-90. [PMID: 10756043 PMCID: PMC111945 DOI: 10.1128/jvi.74.9.4284-4290.2000] [Citation(s) in RCA: 107] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Coxsackievirus B3 (CVB3) is a common factor in human myocarditis. Apoptotic events are present in CVB3-induced disease, but it is unclear how CVB3 is involved in apoptosis and which viral proteins may induce the apoptotic pathway. In this report we demonstrate that the human and murine proapoptotic protein Siva specifically interact with the CVB3 capsid protein VP2. Furthermore, the transcription of Siva is strongly induced in tissue of CVB3-infected mice and is present in the same area which is positively stained for apoptosis, CD27, and CD70. It has been proposed that Siva is involved in the CD27/CD70-transduced apoptosis. Therefore, we suggest a molecular mechanism through which apoptotic events contributes to CVB3-caused pathogenesis.
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Affiliation(s)
- A Henke
- Institute of Virology, Medical Center, Friedrich Schiller University Jena, Germany.
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32
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Huber M, Watson KA, Selinka HC, Carthy CM, Klingel K, McManus BM, Kandolf R. Cleavage of RasGAP and phosphorylation of mitogen-activated protein kinase in the course of coxsackievirus B3 replication. J Virol 1999; 73:3587-94. [PMID: 10196249 PMCID: PMC104132 DOI: 10.1128/jvi.73.5.3587-3594.1999] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Recently, we reported on tyrosine phosphorylation of distinct cellular proteins in the course of enterovirus infections (M. Huber, H.-C. Selinka, and R. Kandolf, J. Virol. 71:595-600, 1997). These phosphorylation events were mediated by Src-like kinases and were shown to be necessary for effective virus replication. That study is now extended by examination of the interaction of the adapter protein Sam68, a cellular target of Src-like kinases which has been shown to interact with the poliovirus 3D polypeptide, with cellular signaling proteins as well as the function of the latter during infection. Here, we report that the RNA-binding and protein-binding protein Sam68 associates with the p21(ras) GTPase-activating protein RasGAP. Remarkably, RasGAP is cleaved during infections with different strains of coxsackievirus B3 as well as with echovirus 11 and echovirus 12, yielding a 104-kDa protein fragment. This cleavage event, which cannot be prevented by the general caspase inhibitor benzyloxycarbonyl-Val-Ala-Asp-fluoromethylketone, may promote the activation of the Ras pathway, as shown by the activating dual phosphorylation of the mitogen-activated protein kinases Erk-1 and Erk-2 in the late phase of infection. Moreover, downstream targets of the mitogen-activated protein kinases, i.e., the p21(ras) exchange factor Sos-1 and cytoplasmic phospholipase A2, are phosphorylated with parallel time courses during infection. Activation or inhibition of cellular signaling pathways may play a general role in regulating effective enterovirus replication and pathogenesis, and the results of this study begin to unravel the molecular cross talk between enterovirus infection and key cellular signaling networks.
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Affiliation(s)
- M Huber
- Department of Molecular Pathology, Institute for Pathology, University of Tübingen, D-72076 Tübingen, Germany
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Lawson TG, Gronros DL, Evans PE, Bastien MC, Michalewich KM, Clark JK, Edmonds JH, Graber KH, Werner JA, Lurvey BA, Cate JM. Identification and Characterization of a Protein Destruction Signal in the Encephalomyocarditis Virus 3C Protease. J Biol Chem 1999. [DOI: 10.1074/jbc.274.14.9871] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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Wang QM. Protease inhibitors as potential antiviral agents for the treatment of picornaviral infections. PROGRESS IN DRUG RESEARCH. FORTSCHRITTE DER ARZNEIMITTELFORSCHUNG. PROGRES DES RECHERCHES PHARMACEUTIQUES 1999; 52:197-219. [PMID: 10396129 DOI: 10.1007/978-3-0348-8730-4_5] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/13/2023]
Abstract
The picornavirus family contains several human pathogens including human rhinovirus (HRV) and hepatitis A virus (HAV). In the case of HRVs, these small single-stranded positive-sense RNA viruses translate their genetic information into a polyprotein precursor which is further processed mainly by two viral proteases designated 2A and 3C. The 2A protease (2Apro) makes the first cleavage between the structural and non-structural proteins, while 3C protease (3Cpro) catalyzes most of the remaining internal cleavages. It has been shown that both 2Apro and 3Cpro are cysteine proteases but their overall protein folding is more like trypsin-type serine proteases. Due to their unique protein structure and essential roles in viral replication, 2Apro and 3Cpro have been viewed as excellent targets for antiviral intervention. In recent years, considerable efforts have been made in the development of antiviral compounds targeting these proteases. This article summarizes the recent approaches in the design of novel 2A and 3C protease inhibitors as potential antiviral agents for the treatment of picornaviral infections.
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Affiliation(s)
- Q M Wang
- Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN 46285, USA
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Zell R, Stelzner A. Application of genome sequence information to the classification of bovine enteroviruses: the importance of 5'- and 3'-nontranslated regions. Virus Res 1997; 51:213-29. [PMID: 9498619 DOI: 10.1016/s0168-1702(97)00096-8] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Comparative genomics of viruses in evolutionary and phylogenetic studies is well established. Previous nucleic acid sequence analyses have demonstrated that enteroviruses and rhinoviruses of the family Picornaviridae exhibit a similar structure of the 5'-nontranslated region (NTR) differing significantly from the 5'-NTR of cardiovirus, aphthovirus, hepatovirus, and echovirus 22 (provisionally parechovirus 1). Available nucleotide sequence information of the 5'- and 3'-nontranslated regions of more than 70 serotypes of enteroviruses, bovine enteroviruses and rhinoviruses has been compared and correlated with previous findings obtained after analysis of the coding and noncoding genome regions. As a result, the 5'- and 3'-NTRs of all three virus groups are characterized by group-specific nucleotide sequences. Focusing on bovine enterovirus (BEV) serotypes, unique characteristics in all secondary structures of the NTRs were observed. These features clearly separate the BEVs from the human enteroviruses and rhinoviruses. Concerning the 5'-NTR, the most remarkable property is an insertion of about 110 nucleotides between the putative cloverleaf structure at the very 5'-end of the viral genome and the IRES element. This insertion was demonstrated for BEV 1 and 2 and has a predicted folding pattern which is very similar to the 5'-cloverleaf structure. One stem-loop of this second cloverleaf is almost identical to the 3CDpro-binding domain of rhinoviral 5'-cloverleafs. It was also demonstrated that the IRES elements and the 3'-NTRs of both, enteroviruses and rhinoviruses, have group-specific features which differ significantly from the corresponding genome regions of BEV. These results suggest that bovine enteroviruses hold an exceptional taxonomic position besides the established genera Enterovirus and Rhinovirus. Within the Enterovirus and Rhinovirus genera, the existence of virus clusters representing subgenera was previously proposed. Whereas the 5'-NTRs of the four human enterovirus clusters fall into two groups, all four clusters have characteristic secondary structures at the 3'-NTR supporting the concept of enterovirus clusters. For rhinoviruses, the existence of two virus clusters was confirmed.
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Affiliation(s)
- R Zell
- Institut für Virologie, Klinikum der Friedrich-Schiller-Universität, Jena, Germany.
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Gladding RL, Haas AL, Gronros DL, Lawson TG. Evaluation of the susceptibility of the 3C proteases of hepatitis A virus and poliovirus to degradation by the ubiquitin-mediated proteolytic system. Biochem Biophys Res Commun 1997; 238:119-25. [PMID: 9299463 DOI: 10.1006/bbrc.1997.7251] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The picornavirus 3C proteases are required for the processing of viral polyproteins during infections of host cells. Here we report that the 3C protease of the hepatitis A virus, like that of the encephalomyocarditis virus, is a substrate for rapid, ubiquitin-mediated degradation in vitro. Ubiquitin was shown to stimulate the turnover of the hepatitis virus 3C protease, and labeled protease was found to become incorporated into a mixture of high molecular weight species, which is characteristic of conjugation with polyubiquitin chains. In the presence of methylated ubiquitin, a new 33 kDa species formed, consistent with the generation of a monoubiquitin-3C protease conjugate. The rate of degradation of the 3C protease was reduced by inhibitors of the 26S proteasome. A similar evaluation of the 3C protease of poliovirus revealed that it is stable protein and is not conjugated with ubiquitin. It was also determined that the hepatitis A and encephalomyocarditis virus 3C proteases compete with each other for conjugation with ubiquitin and for degradation. This suggests that the two 3C proteases are both recognized by the same ubiquitin system enzyme, or enzymes, responsible for selecting them as targets for destruction.
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Affiliation(s)
- R L Gladding
- Department of Chemistry, Bates College, Lewiston, Maine 04240, USA
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37
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Huber M, Selinka HC, Kandolf R. Tyrosine phosphorylation events during coxsackievirus B3 replication. J Virol 1997; 71:595-600. [PMID: 8985388 PMCID: PMC191089 DOI: 10.1128/jvi.71.1.595-600.1997] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
In order to study cellular and viral determinants of pathogenicity, interactions between coxsackievirus B3 (CVB3) replication and cellular protein tyrosine phosphorylation were investigated. During CVB3 infection of HeLa cells, distinct proteins become phosphorylated on tyrosine residues, as detected by the use of antiphosphotyrosine Western blotting. Two proteins of 48 and 200 kDa showed enhanced tyrosine phosphorylation 4 to 5 h postinfection (p.i.), although virus-induced inhibition of cellular protein synthesis had already occurred 3 to 4 h p.i. Subcellular fractionation experiments revealed distinct localization of tyrosine-phosphorylated proteins of 48 and 200 kDa in the cytosol and membrane fractions of infected cells, respectively. In addition, in Vero cells infected with CVB3, echovirus (EV)11, or EV12, increased tyrosine phosphorylation of a 200-kDa protein was detected 6 h p.i. Herbimycin A, a specific inhibitor of Src-like protein tyrosine kinases, was shown to inhibit virus-induced tyrosine phosphorylations and to reduce the production of progeny virions. In contrast, in cells treated with the inhibitors staurosporine and calphostin C, the synthesis of progeny virions was not affected. Immunoprecipitation experiments suggested that the tyrosine-phosphorylated 200-kDa protein in CVB3-infected cells is of cellular origin. In summary, these investigations have begun to unravel the effect of CVB3 as well as EV11 and EV12 replication on cellular tyrosine phosphorylation and support the importance of tyrosine phosphorylation events for effective virus replication. Such cellular phosphorylation events triggered in the course of enterovirus infection may enhance virus replication.
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Affiliation(s)
- M Huber
- Institute for Pathology, Department of Molecular Pathology, University of Tübingen, Germany
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38
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Zell R, Klingel K, Sauter M, Fortmüller U, Kandolf R. Coxsackieviral proteins functionally recognize the polioviral cloverleaf structure of the 5'-NTR of a chimeric enterovirus RNA: influence of species-specific host cell factors on virus growth. Virus Res 1995; 39:87-103. [PMID: 8837877 DOI: 10.1016/0168-1702(95)00075-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The 5'-non-translated region (NTR) of enteroviruses contains secondary structures which do not only serve in the initiation of translation but also in the initiation of plus-strand RNA synthesis by binding of viral and cellular proteins. To investigate a very early step of enteroviral replication by cis- and trans-complementation, 220 nucleotides of the 5'-region of coxsackievirus B3 (CVB3) were exchanged with the corresponding region of poliovirus type 1 (PV1) to yield the chimeric virus CVB3[PV5']. The viability of this chimera demonstrates that the polioviral cloverleaf structure of the 5'-NTR is functional in the replication of a chimeric CVB3 RNA. The HeLa-generated chimera reveals a 4-nucleotide deletion (nt 232-235) within a short direct repeat. Besides clearly reduced growth characteristics in all permissive cell lines, the chimera exhibits a small-plaque phenotype. The host range is changed since the virus grows well in human HeLa cells, but does not replicate in murine YAC-1 and Ltk cells, although these cell lines are permissive for the replication of both parental viruses. Moreover, in simian Vero, COS-1, or FRhK-4 cells the HeLa-generated chimera CVB3[PV5'] exhibits a strict temperature sensitivity at 39 degrees C. After infection of simian cells with high m.o.i. in situ hybridization data reveal that the chimera replicates in single cells at almost normal rates indicating that only a small fraction of HeLa-generated virus is able to multiplicate in simian cell lines. After passaging the virus chimera in Vero cells two further mutations occur at nucleotide positions 185 and 227. Since this genome region is known to interact with viral proteins and several host cell factors during the initiation of replication and translation, interactions of such factors with either viral RNA or viral proteins may be disturbed but still functional at permissive temperatures in HeLa cells and simian cell lines, whereas murine cell lines are not permissive. These experiments suggest that phenomena like host range, tissue tropism and cell-type specificity may be explained as a complex interplay of cellular surface receptors and intracellular host factors. Such intracellular factors could be part of the enteroviral initiation complex during the plus-strand RNA synthesis or during translation initiation and could be expressed in a tissue-, organ- or species-specific way or might be regulated developmentally.
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Affiliation(s)
- R Zell
- Institut für Pathologie, Molekulare Pathologie, Eberhard-Karls-Universität Tübingen, Germany
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40
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Klump WM, Bergmann I, Müller BC, Ameis D, Kandolf R. Complete nucleotide sequence of infectious Coxsackievirus B3 cDNA: two initial 5' uridine residues are regained during plus-strand RNA synthesis. J Virol 1990; 64:1573-83. [PMID: 2157045 PMCID: PMC249292 DOI: 10.1128/jvi.64.4.1573-1583.1990] [Citation(s) in RCA: 194] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
A full-length reverse-transcribed, infectious cDNA copy of coxsackievirus B3 (CVB3) was used to determine the nucleotide sequence of this cardiotropic enterovirus. Comparison of the nucleotide sequence and the deduced amino acid sequence of the viral precursor polyprotein with the sequences of other group B coxsackieviruses (CVB1 and CVB4) demonstrates a high degree of genetic identity. They share about 80% homology at the nucleotide level and about 90% when the amino acid sequences of the polyproteins are compared. The potential processing sites of the coxsackievirus polyproteins, as deduced from alignment with the poliovirus sequence, are conserved among these enteroviruses with the exception of the cleavage sites between VP1 and 2Apro and between polypeptides 2B and 2C. Comparison of the 5' termini of the enteroviral genomes reveals a high degree of identity, including the initial 5' consensus UUAAAACAGC, suggesting essential functions in virus replication. An important finding concerning the molecular basis of infectivity was that both recombinant CVB3 cDNA and in vitro-synthesized CVB3 RNA transcripts are infectious, although two initial 5' uridine residues found on the authentic CVB3 RNA were missing. Here, we report that cDNA-generated CVB3, as well as CVB3 generated by in vitro-synthesized RNA transcripts, regains the authentic initial 5' uridine residues during replication in transfected cells, indicating that the picornaviral primer molecule VPg-pUpU may be uridylylated in a template-independent fashion. The generation of virus or virus mutants with infectious recombinant CVB3 cDNA and in vitro-synthesized infectious CVB3 transcripts should provide a valuable means for studying the molecular basis of the pathogenicity of this cardiotropic enterovirus.
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Affiliation(s)
- W M Klump
- Max-Planck-Institut für Biochemie, Martinsried, Federal Republic of Germany
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41
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Lawson MA, Semler BL. Picornavirus Protein Processing—Enzymes, Substrates, and Genetic Regulation. Curr Top Microbiol Immunol 1990. [DOI: 10.1007/978-3-642-75602-3_3] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
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Lawson TG, Smith LL, Palmenberg AC, Thach RE. Inducible expression of encephalomyocarditis virus 3C protease activity in stably transformed mouse cell lines. J Virol 1989; 63:5013-22. [PMID: 2555538 PMCID: PMC251161 DOI: 10.1128/jvi.63.12.5013-5022.1989] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
An inducible expression vector system has been developed to facilitate the study of the effects of individual virus gene products on cell function. The vector utilizes the mouse metallothionein promoter carried on the bovine papillomavirus genome. Conditions which optimize the induced expression of open reading frames inserted downstream from the mouse metallothionein promoter have recently been described. In this communication we describe the use of this system to clone and express the encephalomyocarditis virus 3C protease in cultured mouse cells. Stably transformed cell lines could be induced to produce levels of 3C protease activity comparable to those observed during normal virus infection. In spite of this, no effects on cellular protein synthesis rate or membrane permeability were observed. It was also discovered that 3C protease as well as 3C protease-containing polyproteins are turned over. This was true not only in the induced cell clones, but also during the normal course of encephalomyocarditis virus infection, as well as in translation systems in vitro. This phenomenon was highly specific for this family of polypeptides, perhaps explaining their apparent lack of cytotoxic effects.
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Affiliation(s)
- T G Lawson
- Department of Biology, Washington University, St. Louis, Missouri 63130-4899
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