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Arita M. An efficient trans complementation system for in vivo replication of defective poliovirus mutants. J Virol 2024:e0052324. [PMID: 38837378 DOI: 10.1128/jvi.00523-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [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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Devaux CA, Pontarotti P, Levasseur A, Colson P, Raoult D. Is it time to switch to a formulation other than the live attenuated poliovirus vaccine to prevent poliomyelitis? Front Public Health 2024; 11:1284337. [PMID: 38259741 PMCID: PMC10801389 DOI: 10.3389/fpubh.2023.1284337] [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: 08/28/2023] [Accepted: 12/14/2023] [Indexed: 01/24/2024] Open
Abstract
The polioviruses (PVs) are mainly transmitted by direct contact with an infected person through the fecal-oral route and respiratory secretions (or more rarely via contaminated water or food) and have a primary tropism for the gut. After their replication in the gut, in rare cases (far less than 1% of the infected individuals), PVs can spread to the central nervous system leading to flaccid paralysis, which can result in respiratory paralysis and death. By the middle of the 20th century, every year the wild polioviruses (WPVs) are supposed to have killed or paralyzed over half a million people. The introduction of the oral poliovirus vaccines (OPVs) through mass vaccination campaigns (combined with better application of hygiene measures), was a success story which enabled the World Health Organization (WHO) to set the global eradication of poliomyelitis as an objective. However this strategy of viral eradication has its limits as the majority of poliomyelitis cases today arise in individuals infected with circulating vaccine-derived polioviruses (cVDPVs) which regain pathogenicity following reversion or recombination. In recent years (between January 2018 and May 2023), the WHO recorded 8.8 times more cases of polio which were linked to the attenuated OPV vaccines (3,442 polio cases after reversion or recombination events) than cases linked to a WPV (390 cases). Recent knowledge of the evolution of RNA viruses and the exchange of genetic material among biological entities of the intestinal microbiota, call for a reassessment of the polio eradication vaccine strategies.
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Affiliation(s)
- Christian Albert Devaux
- Laboratory Microbes Evolution Phylogeny and Infection (MEPHI), Aix-Marseille Université, IRD, APHM, Institut Hospitalo-Universitaire Méditerranée Infection, Marseille, France
- Centre National de la Recherche Scientifique (CNRS-SNC5039), Marseille, France
| | - Pierre Pontarotti
- Laboratory Microbes Evolution Phylogeny and Infection (MEPHI), Aix-Marseille Université, IRD, APHM, Institut Hospitalo-Universitaire Méditerranée Infection, Marseille, France
- Centre National de la Recherche Scientifique (CNRS-SNC5039), Marseille, France
| | - Anthony Levasseur
- Laboratory Microbes Evolution Phylogeny and Infection (MEPHI), Aix-Marseille Université, IRD, APHM, Institut Hospitalo-Universitaire Méditerranée Infection, Marseille, France
| | - Philippe Colson
- Laboratory Microbes Evolution Phylogeny and Infection (MEPHI), Aix-Marseille Université, IRD, APHM, Institut Hospitalo-Universitaire Méditerranée Infection, Marseille, France
| | - Didier Raoult
- Laboratory Microbes Evolution Phylogeny and Infection (MEPHI), Aix-Marseille Université, IRD, APHM, Institut Hospitalo-Universitaire Méditerranée Infection, Marseille, France
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3
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Doherty JS, Kirkegaard K. Differential inhibition of intra- and inter-molecular protease cleavages by antiviral compounds. J Virol 2023; 97:e0092823. [PMID: 38047713 PMCID: PMC10734437 DOI: 10.1128/jvi.00928-23] [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: 06/27/2023] [Accepted: 09/27/2023] [Indexed: 12/05/2023] Open
Abstract
IMPORTANCE Most protease-targeted antiviral development evaluates the ability of small molecules to inhibit the cleavage of artificial substrates. However, before they can cleave any other substrates, viral proteases need to cleave themselves out of the viral polyprotein in which they have been translated. This can occur either intra- or inter-molecularly. Whether this process occurs intra- or inter-molecularly has implications for the potential for precursors to accumulate and for the effectiveness of antiviral drugs. We argue that evaluating candidate antivirals for their ability to block these cleavages is vital to drug development because the buildup of uncleaved precursors can be inhibitory to the virus and potentially suppress the selection of drug-resistant variants.
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Affiliation(s)
| | - Karla Kirkegaard
- Department of Genetics, Stanford University, Palo Alto, California, USA
- Department of Microbiology and Immunology, Stanford University, Palo Alto, California, USA
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4
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Dobrikov MI, Dobrikova EY, Nardone-White DT, McKay ZP, Brown MC, Gromeier M. Early enterovirus translation deficits extend viral RNA replication and elicit sustained MDA5-directed innate signaling. mBio 2023; 14:e0191523. [PMID: 37962360 PMCID: PMC10746184 DOI: 10.1128/mbio.01915-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Accepted: 10/02/2023] [Indexed: 11/15/2023] Open
Abstract
IMPORTANCE Multiple pattern recognition receptors sense vRNAs and initiate downstream innate signaling: endosomal Toll-like receptors (TLRs) 3, 7, and 8 and cytoplasmic RIG-I-like receptors (RLRs) RIG-I, and MDA5. They engage distinct signaling scaffolds: mitochondrial antiviral signaling protein (RLR), MyD88, and TLR-adaptor interacting with SLC15A4 on the lysosome (TLR7 and TLR8) and toll/IL-1R domain-containing adaptor inducing IFN (TLR3). By virtue of their unusual vRNA structure and direct host cell entry path, the innate response to EVs uniquely is orchestrated by MDA5. We reported that PVSRIPO's profound attenuation and loss of cytopathogenicity triggers MDA5-directed polar TBK1-IRF3 signaling that generates priming of polyfunctional antitumor CD8+ T-cell responses and durable antitumor surveillance in vivo. Here we unraveled EV-host relations that control suppression of host type-I IFN responses and show that PVSRIPO's deficient immediate host eIF4G cleavage generates unopposed MDA5-directed downstream signaling cascades resulting in sustained type-I IFN release.
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Affiliation(s)
- Mikhail I. Dobrikov
- Department of Neurosurgery, Duke University Medical School, Durham, North Carolina, USA
| | - Elena Y. Dobrikova
- Department of Neurosurgery, Duke University Medical School, Durham, North Carolina, USA
| | - Dasean T. Nardone-White
- Department of Neurosurgery, Duke University Medical School, Durham, North Carolina, USA
- Department of Molecular Genetics and Microbiology, Duke University Medical School, Durham, North Carolina, USA
| | - Zachary P. McKay
- Department of Neurosurgery, Duke University Medical School, Durham, North Carolina, USA
| | - Michael C. Brown
- Department of Neurosurgery, Duke University Medical School, Durham, North Carolina, USA
| | - Matthias Gromeier
- Department of Neurosurgery, Duke University Medical School, Durham, North Carolina, USA
- Department of Molecular Genetics and Microbiology, Duke University Medical School, Durham, North Carolina, USA
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5
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Pei J, Liu RL, Yang ZH, Du YX, Qian SS, Meng SL, Guo J, Zhang B, Shen S. Identification of Critical Amino Acids of Coxsackievirus A10 Associated with Cell Tropism and Viral RNA Release during Uncoating. Viruses 2023; 15:2114. [PMID: 37896891 PMCID: PMC10611408 DOI: 10.3390/v15102114] [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: 09/19/2023] [Revised: 10/07/2023] [Accepted: 10/17/2023] [Indexed: 10/29/2023] Open
Abstract
Coxsackievirus A10 (CV-A10) is a prevailing causative agent of hand-foot-mouth disease, necessitating the isolation and adaptation of appropriate strains in cells allowed for human vaccine development. In this study, amino acid sequences of CV-A10 strains with different cell tropism on RD and Vero cells were compared. Various amino acids on the structural and non-structural proteins related to cell tropism were identified. The reverse genetic systems of several CV-A10 strains with RD+/Vero- and RD+/Vero+ cell tropism were developed, and a set of CV-A10 recombinants were produced. The binding, entry, uncoating, and proliferation steps in the life cycle of these viruses were evaluated. P1 replacement of CV-A10 strains with different cell tropism revealed the pivotal role of the structural proteins in cell tropism. Further, seven amino acid substitutions in VP2 and VP1 were introduced to further investigate their roles played in cell tropism. These mutations cooperated in the growth of CV-A10 in Vero cells. Particularly, the valine to isoleucine mutation at the position VP1-236 (V1236I) was found to significantly restrict viral uncoating in Vero cells. Co-immunoprecipitation assays showed that the release of viral RNA from the KREMEN1 receptor-binding virions was restricted in r0195-V1236I compared with the parental strain r0195 (a RD+/Vero+ strain). Overall, this study highlights the dominant effect of structural proteins in CV-A10 adaption in Vero cells and the importance of V1236 in viral uncoating, providing a foundation for the mechanism study of CV-A10 cell tropism, and facilitating the development of vaccine candidates.
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Affiliation(s)
- Jie Pei
- Wuhan Institute of Biological Products Co., Ltd., Wuhan 430207, China; (J.P.); (R.-L.L.); (Z.-H.Y.); (Y.-X.D.); (S.-S.Q.); (S.-L.M.); (J.G.)
| | - Rui-Lun Liu
- Wuhan Institute of Biological Products Co., Ltd., Wuhan 430207, China; (J.P.); (R.-L.L.); (Z.-H.Y.); (Y.-X.D.); (S.-S.Q.); (S.-L.M.); (J.G.)
| | - Zhi-Hui Yang
- Wuhan Institute of Biological Products Co., Ltd., Wuhan 430207, China; (J.P.); (R.-L.L.); (Z.-H.Y.); (Y.-X.D.); (S.-S.Q.); (S.-L.M.); (J.G.)
| | - Ya-Xin Du
- Wuhan Institute of Biological Products Co., Ltd., Wuhan 430207, China; (J.P.); (R.-L.L.); (Z.-H.Y.); (Y.-X.D.); (S.-S.Q.); (S.-L.M.); (J.G.)
| | - Sha-Sha Qian
- Wuhan Institute of Biological Products Co., Ltd., Wuhan 430207, China; (J.P.); (R.-L.L.); (Z.-H.Y.); (Y.-X.D.); (S.-S.Q.); (S.-L.M.); (J.G.)
| | - Sheng-Li Meng
- Wuhan Institute of Biological Products Co., Ltd., Wuhan 430207, China; (J.P.); (R.-L.L.); (Z.-H.Y.); (Y.-X.D.); (S.-S.Q.); (S.-L.M.); (J.G.)
| | - Jing Guo
- Wuhan Institute of Biological Products Co., Ltd., Wuhan 430207, China; (J.P.); (R.-L.L.); (Z.-H.Y.); (Y.-X.D.); (S.-S.Q.); (S.-L.M.); (J.G.)
| | - Bo Zhang
- Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, China;
| | - Shuo Shen
- Wuhan Institute of Biological Products Co., Ltd., Wuhan 430207, China; (J.P.); (R.-L.L.); (Z.-H.Y.); (Y.-X.D.); (S.-S.Q.); (S.-L.M.); (J.G.)
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6
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Ma ZH, Nawal Bahoussi A, Tariq Shah P, Guo YY, Dong L, Wu C, Xing L. Phylogeographic dynamics and molecular characteristics of Enterovirus 71 in China. Front Microbiol 2023; 14:1182382. [PMID: 37275165 PMCID: PMC10235518 DOI: 10.3389/fmicb.2023.1182382] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Accepted: 05/02/2023] [Indexed: 06/07/2023] Open
Abstract
Enterovirus 71 (EV71) and coxsackievirus (CV-A16) are the major etiological agents of hand, foot and mouth disease (HFMD). This report reviewed the full-length genomic sequences of EV71 identified in different provinces of China between 1998 and 2019 (a total of 312) in addition to eight worldwide reference genomes to address the genomic evolution and genetic events. The main prevalent EV71 strians in China are C4 genotypes, co-circulating with a few A, B5, C1, and C2 subgenotypes. A new emerging subgenotype in China was identified and classified as B6 genotype. Phylogeographic analysis revealed multiple branches, where a Jiangsu strain 2006-52-9 (GenBank ID: KP266579.1) was linked to different subgenotypes through multiple long mutant branches, including the CV-A16 viruses through the A genotype. Furthermore, identification of 28 natural recombination events suggests that the emergence of new genotypes are associated with intratypic recombination involving EV71 strains and intertypic recombination between EV71 and CV-A16 strains. Compared with the structural proteins, the non-structural proteins of EV71 seem to be highly variable with the highest variable regions of peptidase C3 (3C protein), P2A, and the N-terminus of RNA-dependent RNA polymerase. This study updates the phylogenetic and phylogeographic information of EV71 and provides clues to the emergence of new genotypes of EV71 based on genetics.
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Affiliation(s)
- Zi-Hui Ma
- Institutes of Biomedical Sciences, Shanxi University, Taiyuan, China
| | | | - Pir Tariq Shah
- Institutes of Biomedical Sciences, Shanxi University, Taiyuan, China
| | - Yan-Yan Guo
- Institutes of Biomedical Sciences, Shanxi University, Taiyuan, China
| | - Li Dong
- Institutes of Biomedical Sciences, Shanxi University, Taiyuan, China
| | - Changxin Wu
- Institutes of Biomedical Sciences, Shanxi University, Taiyuan, China
- Shanxi Provincial Key Laboratory of Medical Molecular Cell Biology, Shanxi University, Taiyuan, China
- Shanxi Provincial Key Laboratory for Prevention and Treatment of Major Infectious Diseases, Taiyuan, China
- The Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Shanxi University, Taiyuan, China
| | - Li Xing
- Institutes of Biomedical Sciences, Shanxi University, Taiyuan, China
- Shanxi Provincial Key Laboratory of Medical Molecular Cell Biology, Shanxi University, Taiyuan, China
- Shanxi Provincial Key Laboratory for Prevention and Treatment of Major Infectious Diseases, Taiyuan, China
- The Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Shanxi University, Taiyuan, China
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7
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Wu X, Cui L, Bai Y, Bian L, Liang Z. Pseudotyped Viruses for Enterovirus. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2023; 1407:209-228. [PMID: 36920699 DOI: 10.1007/978-981-99-0113-5_11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/16/2023]
Abstract
Using a non-pathogenic pseudotyped virus as a surrogate for a wide-type virus in scientific research complies with the recent requirements for biosafety. Enterovirus (EV) contains many species of viruses, which are a type of nonenveloped virus. The preparation of its corresponding pseudotyped virus often needs customized construction compared to some enveloped viruses. This article describes the procedures and challenges in the construction of pseudotyped virus for enterovirus (pseudotyped enterovirus, EVpv) and also introduces the application of EVpv in basic virological research, serological monitoring, and the detection of neutralizing antibody (NtAb).
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Affiliation(s)
- Xing Wu
- Division of Hepatitis Virus & Enterovirus Vaccines, Institute for Biological Products, National Institutes for Food and Drug Control, Beijing, China
- WHO Collaborating Center for Standardization and Evaluation of Biologicals, Beijing, China
| | - Lisha Cui
- Minhai biotechnology Co. Ltd, Beijing, China
| | - Yu Bai
- Division of Hepatitis Virus & Enterovirus Vaccines, Institute for Biological Products, National Institutes for Food and Drug Control, Beijing, China
- WHO Collaborating Center for Standardization and Evaluation of Biologicals, Beijing, China
| | - Lianlian Bian
- Division of Hepatitis Virus & Enterovirus Vaccines, Institute for Biological Products, National Institutes for Food and Drug Control, Beijing, China
- WHO Collaborating Center for Standardization and Evaluation of Biologicals, Beijing, China
| | - Zhenglun Liang
- Division of Hepatitis Virus & Enterovirus Vaccines, Institute for Biological Products, National Institutes for Food and Drug Control, Beijing, China
- WHO Collaborating Center for Standardization and Evaluation of Biologicals, Beijing, China
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Nadkarni R, Chu WC, Lee CQE, Mohamud Y, Yap L, Toh GA, Beh S, Lim R, Fan YM, Zhang YL, Robinson K, Tryggvason K, Luo H, Zhong F, Ho L. Viral proteases activate the CARD8 inflammasome in the human cardiovascular system. J Exp Med 2022; 219:213484. [PMID: 36129453 PMCID: PMC9499823 DOI: 10.1084/jem.20212117] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Revised: 06/18/2022] [Accepted: 08/08/2022] [Indexed: 01/10/2023] Open
Abstract
Nucleotide-binding oligomerization domain (NBD), leucine-rich repeat (LRR) containing protein family (NLRs) are intracellular pattern recognition receptors that mediate innate immunity against infections. The endothelium is the first line of defense against blood-borne pathogens, but it is unclear which NLRs control endothelial cell (EC) intrinsic immunity. Here, we demonstrate that human ECs simultaneously activate NLRP1 and CARD8 inflammasomes in response to DPP8/9 inhibitor Val-boro-Pro (VbP). Enterovirus Coxsackie virus B3 (CVB3)-the most common cause of viral myocarditis-predominantly activates CARD8 in ECs in a manner that requires viral 2A and 3C protease cleavage at CARD8 p.G38 and proteasome function. Genetic deletion of CARD8 in ECs and human embryonic stem cell-derived cardiomyocytes (HCMs) attenuates CVB3-induced pyroptosis, inflammation, and viral propagation. Furthermore, using a stratified endothelial-cardiomyocyte co-culture system, we demonstrate that deleting CARD8 in ECs reduces CVB3 infection of the underlying cardiomyocytes. Our study uncovers the unique role of CARD8 inflammasome in endothelium-intrinsic anti-viral immunity.
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Affiliation(s)
- Rhea Nadkarni
- Duke-NUS Medical School, Program in Cardiovascular and Metabolic Disorders, Singapore, Singapore
| | - Wern Cui Chu
- Duke-NUS Medical School, Program in Cardiovascular and Metabolic Disorders, Singapore, Singapore
| | - Cheryl Q E Lee
- Duke-NUS Medical School, Program in Cardiovascular and Metabolic Disorders, Singapore, Singapore
| | - Yasir Mohamud
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Lynn Yap
- Duke-NUS Medical School, Program in Cardiovascular and Metabolic Disorders, Singapore, Singapore
| | - Gee Ann Toh
- Lee Kong Chian School of Medicine, Nanyang Technological University Singapore, Singapore, Singapore
| | - Sheryl Beh
- Duke-NUS Medical School, Program in Cardiovascular and Metabolic Disorders, Singapore, Singapore
| | - Radiance Lim
- Duke-NUS Medical School, Program in Cardiovascular and Metabolic Disorders, Singapore, Singapore
| | - Yiyun Michelle Fan
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Yizhuo Lyanne Zhang
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Kim Robinson
- Skin Research Institute of Singapore, A*STAR, Singapore, Singapore
| | - Karl Tryggvason
- Duke-NUS Medical School, Program in Cardiovascular and Metabolic Disorders, Singapore, Singapore
| | - Honglin Luo
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Franklin Zhong
- Lee Kong Chian School of Medicine, Nanyang Technological University Singapore, Singapore, Singapore
- Skin Research Institute of Singapore, A*STAR, Singapore, Singapore
| | - Lena Ho
- Duke-NUS Medical School, Program in Cardiovascular and Metabolic Disorders, Singapore, Singapore
- Institute of Molecular and Cell Biology, A*STAR, Singapore, Singapore
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Moghimi S, Viktorova EG, Gabaglio S, Zimina A, Budnik B, Wynn BG, Sztul E, Belov GA. A Proximity biotinylation assay with a host protein bait reveals multiple factors modulating enterovirus replication. PLoS Pathog 2022; 18:e1010906. [PMID: 36306280 PMCID: PMC9645661 DOI: 10.1371/journal.ppat.1010906] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Revised: 11/09/2022] [Accepted: 09/30/2022] [Indexed: 11/07/2022] Open
Abstract
As ultimate parasites, viruses depend on host factors for every step of their life cycle. On the other hand, cells evolved multiple mechanisms of detecting and interfering with viral replication. Yet, our understanding of the complex ensembles of pro- and anti-viral factors is very limited in virtually every virus-cell system. Here we investigated the proteins recruited to the replication organelles of poliovirus, a representative of the genus Enterovirus of the Picornaviridae family. We took advantage of a strict dependence of enterovirus replication on a host protein GBF1, and established a stable cell line expressing a truncated GBF1 fused to APEX2 peroxidase that effectively supported viral replication upon inhibition of the endogenous GBF1. This construct biotinylated multiple host and viral proteins on the replication organelles. Among the viral proteins, the polyprotein cleavage intermediates were overrepresented, suggesting that the GBF1 environment is linked to viral polyprotein processing. The proteomics characterization of biotinylated host proteins identified multiple proteins previously associated with enterovirus replication, as well as more than 200 new factors recruited to the replication organelles. RNA metabolism proteins, many of which normally localize in the nucleus, constituted the largest group, underscoring the massive release of nuclear factors into the cytoplasm of infected cells and their involvement in viral replication. Functional analysis of several newly identified proteins revealed both pro- and anti-viral factors, including a novel component of infection-induced stress granules. Depletion of these proteins similarly affected the replication of diverse enteroviruses indicating broad conservation of the replication mechanisms. Thus, our data significantly expand the knowledge of the composition of enterovirus replication organelles, provide new insights into viral replication, and offer a novel resource for identifying targets for anti-viral interventions.
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Affiliation(s)
- Seyedehmahsa Moghimi
- Department of Veterinary Medicine and Virginia-Maryland College of Veterinary Medicine, University of Maryland, College Park, Maryland, United States of America
| | - Ekaterina G. Viktorova
- Department of Veterinary Medicine and Virginia-Maryland College of Veterinary Medicine, University of Maryland, College Park, Maryland, United States of America
| | - Samuel Gabaglio
- Department of Veterinary Medicine and Virginia-Maryland College of Veterinary Medicine, University of Maryland, College Park, Maryland, United States of America
| | - Anna Zimina
- Department of Veterinary Medicine and Virginia-Maryland College of Veterinary Medicine, University of Maryland, College Park, Maryland, United States of America
| | - Bogdan Budnik
- Mass Spectrometry and Proteomics Resource Laboratory (MSPRL), FAS Division of Science, Harvard University, Cambridge, Massachusetts, United States of America
| | - Bridge G. Wynn
- Department of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham; Birmingham, Alabama, United States of America
| | - Elizabeth Sztul
- Department of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham; Birmingham, Alabama, United States of America
| | - George A. Belov
- Department of Veterinary Medicine and Virginia-Maryland College of Veterinary Medicine, University of Maryland, College Park, Maryland, United States of America
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Ravn Warncke S, Rohde Knudsen C. Detection methods targeting the positive- and negative-sense RNA transcripts from plus-stranded RNA viruses. APMIS 2021; 130:284-292. [PMID: 34939239 PMCID: PMC9306919 DOI: 10.1111/apm.13202] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Accepted: 12/16/2021] [Indexed: 11/27/2022]
Abstract
The largest group of viruses in the Baltimore classification system comprises viruses with a positive-sense, single-stranded RNA genome. Once the viral genome is released into the cytoplasm of a specific host cell following virus entry, it functions directly as a mRNA and the virus-encoded proteins that are essential for genome replication, are produced by the translation apparatus of the host cell. The positive-sense genome is replicated in two stages, initially the positive strand is copied to make a negative-sense RNA, which then functions as the template for transcription of many new positive-sense genomes. Virus infections can be detected at different stages throughout the infection cycle for diagnostic and scientific purposes. Here, the advantages and disadvantages of some of the relevant methods for genome detection will be briefly reviewed with special emphasis on techniques allowing strand-specific RNA detection. Furthermore, tools of the future are considered.
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Affiliation(s)
- Signe Ravn Warncke
- Department of Molecular Biology & Genetics, University of Aarhus, Gustav Wieds Vej 10 C, DK-8000, Aarhus C, Denmark
| | - Charlotte Rohde Knudsen
- Department of Molecular Biology & Genetics, University of Aarhus, Gustav Wieds Vej 10 C, DK-8000, Aarhus C, Denmark
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11
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Interaction of Poliovirus Capsid Proteins with the Cellular Autophagy Pathway. Viruses 2021; 13:v13081587. [PMID: 34452452 PMCID: PMC8402707 DOI: 10.3390/v13081587] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Revised: 07/28/2021] [Accepted: 08/10/2021] [Indexed: 12/23/2022] Open
Abstract
The capsid precursor P1 constitutes the N-terminal part of the enterovirus polyprotein. It is processed into VP0, VP3, and VP1 by the viral proteases, and VP0 is cleaved autocatalytically into VP4 and VP2. We observed that poliovirus VP0 is recognized by an antibody against a cellular autophagy protein, LC3A. The LC3A-like epitope overlapped the VP4/VP2 cleavage site. Individually expressed VP0-EGFP and P1 strongly colocalized with a marker of selective autophagy, p62/SQSTM1. To assess the role of capsid proteins in autophagy development we infected different cells with poliovirus or encapsidated polio replicon coding for only the replication proteins. We analyzed the processing of LC3B and p62/SQSTM1, markers of the initiation and completion of the autophagy pathway and investigated the association of the viral antigens with these autophagy proteins in infected cells. We observed cell-type-specific development of autophagy upon infection and found that only the virion signal strongly colocalized with p62/SQSTM1 early in infection. Collectively, our data suggest that activation of autophagy is not required for replication, and that capsid proteins contain determinants targeting them to p62/SQSTM1-dependent sequestration. Such a strategy may control the level of capsid proteins so that viral RNAs are not removed from the replication/translation pool prematurely.
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Domanska A, Guryanov S, Butcher SJ. A comparative analysis of parechovirus protein structures with other picornaviruses. Open Biol 2021; 11:210008. [PMID: 34315275 PMCID: PMC8316810 DOI: 10.1098/rsob.210008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Parechoviruses belong to the genus Parechovirus within the family Picornaviridae and are non-enveloped icosahedral viruses with a single-stranded RNA genome. Parechoviruses include human and animal pathogens classified into six species. Those that infect humans belong to the Parechovirus A species and can cause infections ranging from mild gastrointestinal or respiratory illness to severe neonatal sepsis. There are no approved antivirals available to treat parechovirus (nor any other picornavirus) infections. In this parechovirus review, we focus on the cleaved protein products resulting from the polyprotein processing after translation comparing and contrasting their known or predicted structures and functions to those of other picornaviruses. The review also includes our original analysis from sequence and structure prediction. This review highlights significant structural differences between parechoviral and other picornaviral proteins, suggesting that parechovirus drug development should specifically be directed to parechoviral targets.
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Affiliation(s)
- Aušra Domanska
- Faculty of Biological and Environmental Sciences, Molecular and Integrative Bioscience Research Programme, and Helsinki Institute of Life Sciences-Institute of Biotechnology, University of Helsinki, FI-00014 Helsinki, Finland
| | - Sergey Guryanov
- Faculty of Biological and Environmental Sciences, Molecular and Integrative Bioscience Research Programme, and Helsinki Institute of Life Sciences-Institute of Biotechnology, University of Helsinki, FI-00014 Helsinki, Finland
| | - Sarah J Butcher
- Faculty of Biological and Environmental Sciences, Molecular and Integrative Bioscience Research Programme, and Helsinki Institute of Life Sciences-Institute of Biotechnology, University of Helsinki, FI-00014 Helsinki, Finland
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13
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Enterovirus 2A pro Cleavage of the YTHDF m 6A Readers Implicates YTHDF3 as a Mediator of Type I Interferon-Driven JAK/STAT Signaling. mBio 2021; 12:mBio.00116-21. [PMID: 33849973 PMCID: PMC8092205 DOI: 10.1128/mbio.00116-21] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Enteroviruses (EV) deploy two proteases that mediate viral polyprotein cleavage and host cell manipulation. Here, we report that EV 2A proteases cleave all three members of the YTHDF protein family, cytosolic N 6-methyladenosine (m6A) "readers" that regulate target mRNA fate. YTHDF protein cleavage occurs very early during infection, before viral translation is detected or cytopathogenic effects are observed. Preemptive YTHDF protein depletion enhanced viral translation and replication but only in cells with restrained viral translation, signs of inefficient 2A protease activity, and protective innate host immune responses. This effect corresponded with repression of interferon (IFN)-stimulated gene (ISG) induction, while type I/III IFN production was not significantly altered. Moreover, YTHDF3 depletion impaired JAK/STAT signaling in cells treated with type I, but not type II, IFN. YTHDF3 depletion's stimulatory effect on viral dynamics was dampened by JAK/STAT blockade and enhanced by type I IFN pretreatment of cells. We propose that EV 2A proteases cleave YTHDF proteins to antagonize ISG induction in infected cells.IMPORTANCE It is believed that ∼7,000 messenger RNAs (mRNAs) are subject to N 6-methyladenosine modification. The biological significance of this remains mysterious. The YTHDF m6A readers are three related proteins with high affinity for m6A-modified mRNA, yet their biological functions remain obscure. We discovered that polio/enteroviruses elicit very early proteolysis of YTHDF1 to 3 in infected cells. Our research demonstrates that YTHDF3 acts as a positive regulator of antiviral JAK/STAT signaling in response to positive single-strand RNA virus infection, enabling type I interferon (IFN)-mediated gene regulatory programs to unfurl in infected cells. Our observation of viral degradation of the YTHDF proteins demonstrates that they are key response modifiers in the innate antiviral immune response.
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14
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Defining the proteolytic landscape during enterovirus infection. PLoS Pathog 2020; 16:e1008927. [PMID: 32997711 PMCID: PMC7549765 DOI: 10.1371/journal.ppat.1008927] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Revised: 10/12/2020] [Accepted: 08/24/2020] [Indexed: 12/20/2022] Open
Abstract
Viruses cleave cellular proteins to remodel the host proteome. The study of these cleavages has revealed mechanisms of immune evasion, resource exploitation, and pathogenesis. However, the full extent of virus-induced proteolysis in infected cells is unknown, mainly because until recently the technology for a global view of proteolysis within cells was lacking. Here, we report the first comprehensive catalog of proteins cleaved upon enterovirus infection and identify the sites within proteins where the cleavages occur. We employed multiple strategies to confirm protein cleavages and assigned them to one of the two enteroviral proteases. Detailed characterization of one substrate, LSM14A, a p body protein with a role in antiviral immunity, showed that cleavage of this protein disrupts its antiviral function. This study yields a new depth of information about the host interface with a group of viruses that are both important biological tools and significant agents of disease. Enteroviruses are associated with a variety of human diseases, including gastroenteritis, the common cold, hand-foot-and-mouth disease, acute hemorrhagic conjunctivitis, and skin rash. In some cases, the infection can lead to myocarditis, encephalitis, progressive muscle weakness, and paralysis. Exactly how enteroviruses invade human tissues, defeat the host immune system, and alter normal cell biology is unknown. Understanding these cellular and molecular mechanisms will blaze the trail for the development of novel vaccine and therapeutic strategies. Here, we have applied a global N-terminomics approach to investigate how various enteroviruses recruit their proteases to remodel an infected cell, disarm host immunity, and create a favorable environment for their replication. This effort identified several new protease substrates, which we then confirmed by other experimental approaches. To our knowledge, this is the first systematic analysis of host proteins targeted for cleavage during enterovirus infection. The data generated in this study will serve as a valuable resource for the research community in the quest to uncover the molecular details of enterovirus cell biology and disease pathogenesis.
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15
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Mosaheb MM, Brown MC, Dobrikova EY, Dobrikov MI, Gromeier M. Harnessing virus tropism for dendritic cells for vaccine design. Curr Opin Virol 2020; 44:73-80. [PMID: 32771959 DOI: 10.1016/j.coviro.2020.07.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Accepted: 07/17/2020] [Indexed: 01/13/2023]
Abstract
Dendritic cells (DCs) are pivotal stimulators of T cell responses. They provide essential signals (epitope presentation, proinflammatory cytokines, co-stimulation) to T cells and prime adaptive immunity. Therefore, they are paramount to immunization strategies geared to generate T cell immunity. The inflammatory signals DCs respond to, classically occur in the context of acute virus infection. Yet, enlisting viruses for engaging DCs is hampered by their penchant for targeting DCs with sophisticated immune evasive and suppressive ploys. In this review, we discuss our work on devising vectors based on a recombinant polio:rhinovirus chimera for effectively targeting and engaging DCs. We are juxtaposing this approach with commonly used, recently studied dsDNA virus vector platforms.
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Affiliation(s)
- Mubeen M Mosaheb
- Departments of Molecular Genetics & Microbiology and Neurosurgery, Duke University Medical School, MSRB1 Room 423, Box 3020 Durham, NC 27710, United States
| | - Michael C Brown
- Departments of Molecular Genetics & Microbiology and Neurosurgery, Duke University Medical School, MSRB1 Room 423, Box 3020 Durham, NC 27710, United States
| | - Elena Y Dobrikova
- Departments of Molecular Genetics & Microbiology and Neurosurgery, Duke University Medical School, MSRB1 Room 423, Box 3020 Durham, NC 27710, United States
| | - Mikhail I Dobrikov
- Departments of Molecular Genetics & Microbiology and Neurosurgery, Duke University Medical School, MSRB1 Room 423, Box 3020 Durham, NC 27710, United States
| | - Matthias Gromeier
- Departments of Molecular Genetics & Microbiology and Neurosurgery, Duke University Medical School, MSRB1 Room 423, Box 3020 Durham, NC 27710, United States.
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Human Enterovirus Group B Viruses Rely on Vimentin Dynamics for Efficient Processing of Viral Nonstructural Proteins. J Virol 2020; 94:JVI.01393-19. [PMID: 31619557 PMCID: PMC6955253 DOI: 10.1128/jvi.01393-19] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Accepted: 10/08/2019] [Indexed: 12/15/2022] Open
Abstract
We report that several viruses from the human enterovirus group B cause massive vimentin rearrangements during lytic infection. Comprehensive studies suggested that viral protein synthesis was triggering the vimentin rearrangements. Blocking the host cell vimentin dynamics with β, β'-iminodipropionitrile (IDPN) did not significantly affect the production of progeny viruses and only moderately lowered the synthesis of structural proteins such as VP1. In contrast, the synthesis of the nonstructural proteins 2A, 3C, and 3D was drastically lowered. This led to attenuation of the cleavage of the host cell substrates PABP and G3BP1 and reduced caspase activation, leading to prolonged cell survival. Furthermore, the localization of the proteins differed in the infected cells. Capsid protein VP1 was found diffusely around the cytoplasm, whereas 2A and 3D followed vimentin distribution. Based on protein blotting, smaller amounts of nonstructural proteins did not result from proteasomal degradation but from lower synthesis without intact vimentin cage structure. In contrast, inhibition of Hsp90 chaperone activity, which regulates P1 maturation, lowered the amount of VP1 but had less effect on 2A. The results suggest that the vimentin dynamics regulate viral nonstructural protein synthesis while having less effect on structural protein synthesis or overall infection efficiency. The results presented here shed new light on differential fate of structural and nonstructural proteins of enteroviruses, having consequences on host cell survival.IMPORTANCE A virus needs the host cell in order to replicate and produce new progeny viruses. For this, the virus takes over the host cell and modifies it to become a factory for viral proteins. Irrespective of the specific virus family, these proteins can be divided into structural and nonstructural proteins. Structural proteins are the building blocks for the new progeny virions, whereas the nonstructural proteins orchestrate the takeover of the host cell and its functions. Here, we have shown a mechanism that viruses exploit in order to regulate the host cell. We show that viral protein synthesis induces vimentin cages, which promote production of specific viral proteins that eventually control apoptosis and host cell death. This study specifies vimentin as the key regulator of these events and indicates that viral proteins have different fates in the cells depending on their association with vimentin cages.
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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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18
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Huang SW, Cheng D, Wang JR. Enterovirus A71: virulence, antigenicity, and genetic evolution over the years. J Biomed Sci 2019; 26:81. [PMID: 31630680 PMCID: PMC6802317 DOI: 10.1186/s12929-019-0574-1] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Accepted: 10/01/2019] [Indexed: 01/06/2023] Open
Abstract
As a neurotropic virus, enterovirus A71 (EV-A71) emerge and remerge in the Asia-Pacific region since the 1990s, and has continuously been a threat to global public health, especially in children. Annually, EV-A71 results in hand-foot-and-mouth disease (HFMD) and occasionally causes severe neurological disease. Here we reviewed the global epidemiology and genotypic evolution of EV-A71 since 1997. The natural selection, mutation and recombination events observed in the genetic evolution were described. In addition, we have updated the antigenicity and virulence determinants that are known to date. Understanding EV-A71 epidemiology, genetic evolution, antigenicity, and virulence determinants can expand our insights of EV-A71 pathogenesis, which may benefit us in the future.
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Affiliation(s)
- Sheng-Wen Huang
- National Mosquito-Borne Diseases Control Research Center, National Health Research Institutes, Tainan, Taiwan
| | - Dayna Cheng
- National Institute of Infectious Diseases and Vaccinology, National Health Research Institutes, Tainan, Taiwan
| | - Jen-Ren Wang
- National Institute of Infectious Diseases and Vaccinology, National Health Research Institutes, Tainan, Taiwan. .,Department of Medical Laboratory Science and Biotechnology, College of Medicine, National Cheng Kung University, Tainan, Taiwan. .,Center of Infectious Disease and Signaling Research, National Cheng Kung University, One, University Road, Tainan, 701, Taiwan. .,Department of Pathology, National Cheng Kung University Hospital, Tainan, Taiwan.
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19
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Identification of plasticity and interactions of a highly conserved motif within a picornavirus capsid precursor required for virus infectivity. Sci Rep 2019; 9:11747. [PMID: 31409836 PMCID: PMC6692319 DOI: 10.1038/s41598-019-48170-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Accepted: 07/30/2019] [Indexed: 02/06/2023] Open
Abstract
The picornavirus family includes poliovirus (PV) (genus: enterovirus), human rhinoviruses (enterovirus) and foot-and-mouth disease virus (FMDV) (aphthovirus). These are responsible for important human and animal health concerns worldwide including poliomyelitis, the common cold and foot-and-mouth disease (FMD) respectively. In picornavirus particles, the positive-sense RNA genome (ca. 7–9 kb) is packaged within a protein shell (capsid) usually consisting of three surface exposed proteins, VP1, VP2 and VP3 plus the internal VP4, which are generated following cleavage of the capsid precursor by a virus-encoded protease. We have previously identified a motif near the C-terminus of FMDV VP1 that is required for capsid precursor processing. This motif is highly conserved among other picornaviruses, and is also likely to be important for their capsid precursor processing. We have now determined the plasticity of residues within this motif for virus infectivity and found an important interaction between FMDV residue VP1 R188 within this conserved motif and residue W129 in VP2 that is adjacent in the virus capsid. The FMDV (VP1 R188A) mutant virus has only been rescued with the secondary substitution VP2 W129R. This additional change compensates for the defect resulting from the VP1 R188A substitution and restored both capsid precursor processing and virus viability.
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Validating Enterovirus D68-2A pro as an Antiviral Drug Target and the Discovery of Telaprevir as a Potent D68-2A pro Inhibitor. J Virol 2019; 93:JVI.02221-18. [PMID: 30674624 DOI: 10.1128/jvi.02221-18] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Accepted: 01/11/2019] [Indexed: 02/08/2023] Open
Abstract
Enterovirus D68 (EV-D68) is a viral pathogen that leads to severe respiratory illness and has been linked with the development of acute flaccid myelitis (AFM) in children. No vaccines or antivirals are currently available for EV-D68 infection, and treatment options for hospitalized patients are limited to supportive care. Here, we report the expression of the EV-D68 2A protease (2Apro) and characterization of its enzymatic activity. Furthermore, we discovered that telaprevir, an FDA-approved drug used for the treatment of hepatitis C virus (HCV) infections, is a potent antiviral against EV-D68 by targeting the 2Apro enzyme. Using a fluorescence resonance energy transfer-based substrate cleavage assay, we showed that the purified EV-D68 2Apro has proteolytic activity selective against a peptide sequence corresponding to the viral VP1-2A polyprotein junction. Telaprevir inhibits EV-D68 2Apro through a nearly irreversible, biphasic binding mechanism. In cell culture, telaprevir showed submicromolar-to-low-micromolar potency against several recently circulating neurotropic strains of EV-D68 in different human cell lines. To further confirm the antiviral drug target, serial viral passage experiments were performed to select for resistance against telaprevir. An N84T mutation near the active site of 2Apro was identified in resistant viruses, and this mutation reduced the potency of telaprevir in both the enzymatic and cellular antiviral assays. Collectively, we report for the first time the in vitro enzymatic activity of EV-D68 2Apro and the identification of telaprevir as a potent EV-D68 2Apro inhibitor. These findings implicate EV-D68 2Apro as an antiviral drug target and highlight the repurposing potential of telaprevir to treat EV-D68 infection.IMPORTANCE A 2014 EV-D68 outbreak in the United States has been linked to the development of acute flaccid myelitis in children. Unfortunately, no treatment options against EV-D68 are currently available, and the development of effective therapeutics is urgently needed. Here, we characterize and validate a new EV-D68 drug target, the 2Apro, and identify telaprevir-an FDA-approved drug used to treat hepatitis C virus (HCV) infections-as a potent antiviral with a novel mechanism of action toward 2Apro 2Apro functions as a viral protease that cleaves a peptide sequence corresponding to the VP1-2A polyprotein junction. The binding of telaprevir potently inhibits its enzymatic activity, and using drug resistance selection, we show that the potent antiviral activity of telaprevir was due to 2Apro inhibition. This is the first inhibitor to selectively target the 2Apro from EV-D68 and can be used as a starting point for the development of therapeutics with selective activity against EV-D68.
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21
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Kristensen T, Belsham GJ. Identification of a short, highly conserved, motif required for picornavirus capsid precursor processing at distal sites. PLoS Pathog 2019; 15:e1007509. [PMID: 30657784 PMCID: PMC6338358 DOI: 10.1371/journal.ppat.1007509] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Accepted: 12/06/2018] [Indexed: 12/15/2022] Open
Abstract
Many picornaviruses cause important diseases in humans and other animals including poliovirus, rhinoviruses (causing the common cold) and foot-and-mouth disease virus (FMDV). These small, non-enveloped viruses comprise a positive-stranded RNA genome (ca. 7-9 kb) enclosed within a protein shell composed of 60 copies of three or four different capsid proteins. For the aphthoviruses (e.g. FMDV) and cardioviruses, the capsid precursor, P1-2A, is cleaved by the 3C protease (3Cpro) to generate VP0, VP3 and VP1 plus 2A. For enteroviruses, e.g. poliovirus, the capsid precursor is P1 alone, which is cleaved by the 3CD protease to generate just VP0, VP3 and VP1. The sequences required for correct processing of the FMDV capsid protein precursor in mammalian cells were analyzed. Truncation of the P1-2A precursor from its C-terminus showed that loss of the 2A peptide (18 residues long) and 27 residues from the C-terminus of VP1 (211 residues long) resulted in a precursor that cannot be processed by 3Cpro although it still contained two unmodified internal cleavage sites (VP0/VP3 and VP3/VP1 junctions). Furthermore, introduction of small deletions within P1-2A identified residues 185-190 within VP1 as being required for 3Cpro-mediated processing and for optimal accumulation of the precursor. Within this C-terminal region of VP1, five of these residues (YCPRP), are very highly conserved in all FMDVs and are also conserved amongst other picornaviruses. Mutant FMDV P1-2A precursors with single amino acid substitutions within this motif were highly resistant to cleavage at internal junctions. Such substitutions also abrogated virus infectivity. These results can explain earlier observations that loss of the C-terminus (including the conserved motif) from the poliovirus capsid precursor conferred resistance to processing. Thus, this motif seems essential for maintaining the correct structure of picornavirus capsid precursors prior to processing and subsequent capsid assembly; it may represent a site that interacts with cellular chaperones.
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Affiliation(s)
- Thea Kristensen
- DTU National Veterinary Institute, Technical University of Denmark, Lindholm, Kalvehave, Denmark
| | - Graham J. Belsham
- DTU National Veterinary Institute, Technical University of Denmark, Lindholm, Kalvehave, Denmark
- * E-mail:
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22
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Wang Y, Ma L, Stipkovits L, Szathmary S, Li X, Liu Y. The Strategy of Picornavirus Evading Host Antiviral Responses: Non-structural Proteins Suppress the Production of IFNs. Front Microbiol 2018; 9:2943. [PMID: 30619109 PMCID: PMC6297142 DOI: 10.3389/fmicb.2018.02943] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Accepted: 11/15/2018] [Indexed: 12/22/2022] Open
Abstract
Viral infections trigger the innate immune system to produce interferons (IFNs), which play important role in host antiviral responses. Co-evolution of viruses with their hosts has favored development of various strategies to evade the effects of IFNs, enabling viruses to survive inside host cells. One such strategy involves inhibition of IFN signaling pathways by non-structural proteins. In this review, we provide a brief overview of host signaling pathways inducing IFN production and their suppression by picornavirus non-structural proteins. Using this strategy, picornaviruses can evade the host immune response and replicate inside host cells.
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Affiliation(s)
- Yining Wang
- State Key Laboratory of Veterinary Etiological Biology, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China
| | - Lina Ma
- State Key Laboratory of Veterinary Etiological Biology, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China
| | | | | | - Xuerui Li
- State Key Laboratory of Veterinary Etiological Biology, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China
| | - Yongsheng Liu
- State Key Laboratory of Veterinary Etiological Biology, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China
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23
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Han M, Rajput C, Hinde JL, Wu Q, Lei J, Ishikawa T, Bentley JK, Hershenson MB. Construction of a recombinant rhinovirus accommodating fluorescent marker expression. Influenza Other Respir Viruses 2018; 12:717-727. [PMID: 30120824 PMCID: PMC6185886 DOI: 10.1111/irv.12602] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Revised: 07/02/2018] [Accepted: 08/15/2018] [Indexed: 12/28/2022] Open
Abstract
Background Rhinovirus (RV) causes the common cold and asthma exacerbations. The RV genome is a 7.3 kb single‐strand positive‐sense RNA. Objective Using minor group RV1A as a backbone, we sought to design and generate a recombinant RV1A accommodating fluorescent marker expression, thereby allowing tracking of viral infection. Method Recombinant RV1A infectious cDNA clones harboring the coding sequence of green fluorescent protein (GFP), Renilla luciferase, or iLOV (for light, oxygen, or voltage sensing) were engineered and constructed. RV‐infected cells were determined by flow cytometry, immunohistochemistry, and immunofluorescence microscopy. Results RV1A‐GFP showed a cytopathic effect in HeLa cells but failed to express GFP or Renilla luciferase due to deletion. The smaller fluorescent protein construct, RV1A‐iLOV, was stably expressed in infected cells. RV1A‐iLOV expression was used to examine the antiviral effect of bafilomycin in HeLa cells. Compared to parental virus, RV1A‐iLOV infection of BALB/c mice yielded a similar viral load and level of cytokine mRNA expression. However, imaging of fixed lung tissue failed to reveal a fluorescent signal, likely due to the oxidation and bleaching of iLOV‐bound flavin mononucleotide. We therefore employed an anti‐iLOV antibody for immunohistochemical and immunofluorescence imaging. The iLOV signal was identified in airway epithelial cells and CD45+ CD11b+ lung macrophages. Conclusions These results suggest that RV1A‐iLOV is a useful molecular tool for studying RV pathogenesis. The construction strategy for RV1A‐iLOV could be applied to other RV serotypes. However, the detection of iLOV‐expressing RV in fixed tissue required the use of an anti‐iLOV antibody, limiting the value of this construct.
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Affiliation(s)
- Mingyuan Han
- Department of Pediatrics & Communicable Diseases, University of Michigan Medical School, Ann Arbor, Michigan
| | - Charu Rajput
- Department of Pediatrics & Communicable Diseases, University of Michigan Medical School, Ann Arbor, Michigan
| | - Joanna L Hinde
- Department of Pediatrics & Communicable Diseases, University of Michigan Medical School, Ann Arbor, Michigan
| | - Qian Wu
- Department of Pediatrics & Communicable Diseases, University of Michigan Medical School, Ann Arbor, Michigan
| | - Jing Lei
- Department of Pediatrics & Communicable Diseases, University of Michigan Medical School, Ann Arbor, Michigan
| | - Tomoko Ishikawa
- Department of Pediatrics & Communicable Diseases, University of Michigan Medical School, Ann Arbor, Michigan
| | - J Kelley Bentley
- Department of Pediatrics & Communicable Diseases, University of Michigan Medical School, Ann Arbor, Michigan
| | - Marc B Hershenson
- Department of Pediatrics & Communicable Diseases, University of Michigan Medical School, Ann Arbor, Michigan.,Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan
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Russo AG, Eden JS, Enosi Tuipulotu D, Shi M, Selechnik D, Shine R, Rollins LA, Holmes EC, White PA. Viral Discovery in the Invasive Australian Cane Toad ( Rhinella marina) Using Metatranscriptomic and Genomic Approaches. J Virol 2018; 92:JVI.00768-18. [PMID: 29899109 PMCID: PMC6096826 DOI: 10.1128/jvi.00768-18] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Accepted: 06/07/2018] [Indexed: 12/19/2022] Open
Abstract
Cane toads are poisonous amphibians that were introduced to Australia in 1935 for insect control. Since then, their population has increased dramatically, and they now threaten many native Australian species. One potential method to control the population is to release a cane toad virus with high mortality rates, yet few cane toad viruses have been characterized. This study samples cane toads from different Australian locations and uses an RNA sequencing and computational approach to find new viruses. We report novel complete picornavirus and retrovirus sequences that were genetically similar to viruses infecting frogs, reptiles, and fish. Using data generated in other studies, we show that these viral sequences are present in cane toads from distinct Australian locations. Three sequences related to circoviruses were also found in the toad genome. The identification of new viral sequences will aid future studies that investigate their prevalence and potential as agents for biocontrol. Cane toads are a notorious invasive species, inhabiting over 1.2 million km2 of Australia and threatening native biodiversity. The release of pathogenic cane toad viruses is one possible biocontrol strategy yet is currently hindered by the poorly described cane toad virome. Metatranscriptomic analysis of 16 cane toad livers revealed the presence of a novel and full-length picornavirus, Rhimavirus A (RhiV-A), a member of a reptile- and amphibian-specific cluster of the Picornaviridae basal to the Kobuvirus-like group. In the combined liver transcriptome, we also identified a complete genome sequence of a distinct epsilonretrovirus, Rhinella marina endogenous retrovirus (RMERV). The recently sequenced cane toad genome contains 8 complete RMERV proviruses as well as 21 additional truncated insertions. The oldest full-length RMERV provirus was estimated to have inserted 1.9 million years ago (MYA). To screen for these viral sequences in additional toads, we analyzed publicly available transcriptomes from six diverse Australian locations. RhiV-A transcripts were identified in toads sampled from three locations across 1,000 km of Australia, stretching to the current Western Australia (WA) invasion front, while RMERV transcripts were observed at all six sites. Finally, we scanned the cane toad genome for nonretroviral endogenous viral elements, finding three sequences related to small DNA viruses in the family Circoviridae. This shows ancestral circoviral infection with subsequent genomic integration. The identification of these current and past viral infections enriches our knowledge of the cane toad virome, an understanding of which will facilitate future work on infection and disease in this important invasive species. IMPORTANCE Cane toads are poisonous amphibians that were introduced to Australia in 1935 for insect control. Since then, their population has increased dramatically, and they now threaten many native Australian species. One potential method to control the population is to release a cane toad virus with high mortality rates, yet few cane toad viruses have been characterized. This study samples cane toads from different Australian locations and uses an RNA sequencing and computational approach to find new viruses. We report novel complete picornavirus and retrovirus sequences that were genetically similar to viruses infecting frogs, reptiles, and fish. Using data generated in other studies, we show that these viral sequences are present in cane toads from distinct Australian locations. Three sequences related to circoviruses were also found in the toad genome. The identification of new viral sequences will aid future studies that investigate their prevalence and potential as agents for biocontrol.
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Affiliation(s)
- Alice G. Russo
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, New South Wales, Australia
| | - John-Sebastian Eden
- Marie Bashir Institute for Infectious Disease and Biosecurity, School of Life and Environmental Sciences and Sydney Medical School, Charles Perkins Centre, The University of Sydney, Sydney, New South Wales, Australia
- The Westmead Institute of Medical Research, Centre for Virus Research, Westmead, NSW, Australia
| | - Daniel Enosi Tuipulotu
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, New South Wales, Australia
| | - Mang Shi
- Marie Bashir Institute for Infectious Disease and Biosecurity, School of Life and Environmental Sciences and Sydney Medical School, Charles Perkins Centre, The University of Sydney, Sydney, New South Wales, Australia
| | - Daniel Selechnik
- School of Life and Environmental Sciences, The University of Sydney, Sydney, New South Wales, Australia
| | - Richard Shine
- School of Life and Environmental Sciences, The University of Sydney, Sydney, New South Wales, Australia
| | - Lee Ann Rollins
- Centre for Integrative Ecology, School of Life and Environmental Sciences, Deakin University, Geelong, Victoria, Australia
- Evolution and Ecology Research Centre, School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, New South Wales, Australia
| | - Edward C. Holmes
- Marie Bashir Institute for Infectious Disease and Biosecurity, School of Life and Environmental Sciences and Sydney Medical School, Charles Perkins Centre, The University of Sydney, Sydney, New South Wales, Australia
| | - Peter A. White
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, New South Wales, Australia
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Oh HS, Banerjee S, Aponte-Diaz D, Sharma SD, Aligo J, Lodeiro MF, Ning G, Sharma R, Arnold JJ, Cameron CE. Multiple poliovirus-induced organelles suggested by comparison of spatiotemporal dynamics of membranous structures and phosphoinositides. PLoS Pathog 2018; 14:e1007036. [PMID: 29702686 PMCID: PMC5942851 DOI: 10.1371/journal.ppat.1007036] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Revised: 05/09/2018] [Accepted: 04/17/2018] [Indexed: 11/25/2022] Open
Abstract
At the culmination of poliovirus (PV) multiplication, membranes are observed that contain phosphatidylinositol-4-phosphate (PI4P) and appear as vesicular clusters in cross section. Induction and remodeling of PI4P and membranes prior to or concurrent with genome replication has not been well studied. Here, we exploit two PV mutants, termed EG and GG, which exhibit aberrant proteolytic processing of the P3 precursor that substantially delays the onset of genome replication and/or impairs virus assembly, to illuminate the pathway of formation of PV-induced membranous structures. For WT PV, changes to the PI4P pool were observed as early as 30 min post-infection. PI4P remodeling occurred even in the presence of guanidine hydrochloride, a replication inhibitor, and was accompanied by formation of membrane tubules throughout the cytoplasm. Vesicular clusters appeared in the perinuclear region of the cell at 3 h post-infection, a time too slow for these structures to be responsible for genome replication. Delays in the onset of genome replication observed for EG and GG PVs were similar to the delays in virus-induced remodeling of PI4P pools, consistent with PI4P serving as a marker of the genome-replication organelle. GG PV was unable to convert virus-induced tubules into vesicular clusters, perhaps explaining the nearly 5-log reduction in infectious virus produced by this mutant. Our results are consistent with PV inducing temporally distinct membranous structures (organelles) for genome replication (tubules) and virus assembly (vesicular clusters). We suggest that the pace of formation, spatiotemporal dynamics, and the efficiency of the replication-to-assembly-organelle conversion may be set by both the rate of P3 polyprotein processing and the capacity for P3 processing to yield 3AB and/or 3CD proteins. All positive-strand RNA viruses replicate their genomes in association with host cell membranes. PV does not just remodel existing membranes, but induces membranes with unique structure and lipid composition. There has been some suggestion that the functions of the PV-induced structures observed during infection may not be those that perform genome replication. This study uses kinetic analysis and kinetic traps of virus-induced membrane formation/transformation and PI4P induction by WT PV and two PV mutants to provide evidence for the existence of a virus-induced genome-replication organelle temporally and spatially distinct from a virus-assembly organelle. In addition, our studies suggest that formation of both organelles may require participation of viral proteins, 3AB and/or 3CD. Therefore, this study provides a new perspective on the cell biology of PV infection and should inspire a fresh look at picornavirus-induced organelles, their functions and the role of P3 proteins in their formation and interconversion.
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Affiliation(s)
- Hyung S. Oh
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Sravani Banerjee
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - David Aponte-Diaz
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Suresh D. Sharma
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Jason Aligo
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Maria F. Lodeiro
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Gang Ning
- Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Rajni Sharma
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Jamie J. Arnold
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Craig E. Cameron
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania, United States of America
- * E-mail:
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26
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Jagdeo JM, Dufour A, Klein T, Solis N, Kleifeld O, Kizhakkedathu J, Luo H, Overall CM, Jan E. N-Terminomics TAILS Identifies Host Cell Substrates of Poliovirus and Coxsackievirus B3 3C Proteinases That Modulate Virus Infection. J Virol 2018; 92:e02211-17. [PMID: 29437971 PMCID: PMC5874412 DOI: 10.1128/jvi.02211-17] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Accepted: 01/26/2018] [Indexed: 12/19/2022] Open
Abstract
Enteroviruses encode proteinases that are essential for processing of the translated viral polyprotein. In addition, viral proteinases also target host proteins to manipulate cellular processes and evade innate antiviral responses to promote replication and infection. Although some host protein substrates of enterovirus proteinases have been identified, the full repertoire of targets remains unknown. We used a novel quantitative in vitro proteomics-based approach, termed terminal amine isotopic labeling of substrates (TAILS), to identify with high confidence 72 and 34 new host protein targets of poliovirus and coxsackievirus B3 (CVB3) 3C proteinases (3Cpros) in HeLa cell and cardiomyocyte HL-1 cell lysates, respectively. We validated a subset of candidate substrates that are targets of poliovirus 3Cproin vitro including three common protein targets, phosphoribosylformylglycinamidine synthetase (PFAS), hnRNP K, and hnRNP M, of both proteinases. 3Cpro-targeted substrates were also cleaved in virus-infected cells but not noncleavable mutant proteins designed from the TAILS-identified cleavage sites. Knockdown of TAILS-identified target proteins modulated infection both negatively and positively, suggesting that cleavage by 3Cpro promotes infection. Indeed, expression of a cleavage-resistant mutant form of the endoplasmic reticulum (ER)-Golgi vesicle-tethering protein p115 decreased viral replication and yield. As the first comprehensive study to identify and validate functional enterovirus 3Cpro substrates in vivo, we conclude that N-terminomics by TAILS is an effective strategy to identify host targets of viral proteinases in a nonbiased manner.IMPORTANCE Enteroviruses are positive-strand RNA viruses that encode proteases that cleave the viral polyprotein into the individual mature viral proteins. In addition, viral proteases target host proteins in order to modulate cellular pathways and block antiviral responses in order to facilitate virus infection. Although several host protein targets have been identified, the entire list of proteins that are targeted is not known. In this study, we used a novel unbiased proteomics approach to identify ∼100 novel host targets of the enterovirus 3C protease, thus providing further insights into the network of cellular pathways that are modulated to promote virus infection.
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Affiliation(s)
- Julienne M Jagdeo
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, British Columbia, Canada
- Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Antoine Dufour
- Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada
- Centre for Blood Research, Faculty of Dentistry, Department of Oral Biological and Medical Sciences, University of British Columbia, Vancouver, British Columbia, Canada
| | - Theo Klein
- Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada
- Centre for Blood Research, Faculty of Dentistry, Department of Oral Biological and Medical Sciences, University of British Columbia, Vancouver, British Columbia, Canada
| | - Nestor Solis
- Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada
- Centre for Blood Research, Faculty of Dentistry, Department of Oral Biological and Medical Sciences, University of British Columbia, Vancouver, British Columbia, Canada
| | - Oded Kleifeld
- School of Biomedical Sciences, Monash University, Victoria, Australia
| | - Jayachandran Kizhakkedathu
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Honglin Luo
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Christopher M Overall
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, British Columbia, Canada
- Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada
- Centre for Blood Research, Faculty of Dentistry, Department of Oral Biological and Medical Sciences, University of British Columbia, Vancouver, British Columbia, Canada
| | - Eric Jan
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, British Columbia, Canada
- Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada
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27
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Modifications to the Foot-and-Mouth Disease Virus 2A Peptide: Influence on Polyprotein Processing and Virus Replication. J Virol 2018; 92:JVI.02218-17. [PMID: 29386286 DOI: 10.1128/jvi.02218-17] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Accepted: 01/20/2018] [Indexed: 12/11/2022] Open
Abstract
Foot-and-mouth disease virus (FMDV) has a positive-sense single-stranded RNA (ssRNA) genome that includes a single, large open reading frame encoding a polyprotein. The cotranslational "cleavage" of this polyprotein at the 2A/2B junction is mediated by the 2A peptide (18 residues in length) using a nonproteolytic mechanism termed "ribosome skipping" or "StopGo." Multiple variants of the 2A polypeptide with this property among the picornaviruses share a conserved C-terminal motif [D(V/I)E(S/T)NPG↓P]. The impact of 2A modifications within this motif on FMDV protein synthesis, polyprotein processing, and virus viability were investigated. Amino acid substitutions are tolerated at residues E14, S15, and N16 within the 2A sequences of infectious FMDVs despite their reported "cleavage" efficiencies at the 2A/2B junction of only ca. 30 to 50% compared to that of the wild type (wt). In contrast, no viruses containing substitutions at residue P17, G18, or P19, which displayed little or no "cleavage" activity in vitro, were rescued, but wt revertants were obtained. The 2A substitutions impaired the replication of an FMDV replicon. Using transient-expression assays, it was shown that certain amino acid substitutions at residues E14, S15, N16, and P19 resulted in partial "cleavage" of a protease-free polyprotein, indicating that these specific residues are not essential for cotranslational "cleavage." Immunofluorescence studies, using full-length FMDV RNA transcripts encoding mutant 2A peptides, indicated that the 2A peptide remained attached to adjacent proteins, presumably 2B. These results show that efficient "cleavage" at the 2A/2B junction is required for optimal virus replication. However, maximal StopGo activity does not appear to be essential for the viability of FMDV.IMPORTANCE Foot-and-mouth disease virus (FMDV) causes one of the most economically important diseases of farm animals. Cotranslational "cleavage" of the FMDV polyprotein precursor at the 2A/2B junction, termed StopGo, is mediated by the short 2A peptide through a nonproteolytic mechanism which leads to release of the nascent protein and continued translation of the downstream sequence. Improved understanding of this process will not only give a better insight into how this peptide influences the FMDV replication cycle but may also assist the application of this sequence in biotechnology for the production of multiple proteins from a single mRNA. Our data show that single amino acid substitutions in the 2A peptide can have a major influence on viral protein synthesis, virus viability, and polyprotein processing. They also indicate that efficient "cleavage" at the 2A/2B junction is required for optimal virus replication. However, maximal StopGo activity is not essential for the viability of FMDV.
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Koehler S, Brähler S, Braun F, Hagmann H, Rinschen MM, Späth MR, Höhne M, Wunderlich FT, Schermer B, Benzing T, Brinkkoetter PT. Construction of a viral T2A-peptide based knock-in mouse model for enhanced Cre recombinase activity and fluorescent labeling of podocytes. Kidney Int 2017; 91:1510-1517. [PMID: 28187984 DOI: 10.1016/j.kint.2016.12.011] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Revised: 11/23/2016] [Accepted: 12/01/2016] [Indexed: 12/16/2022]
Abstract
Podocyte injury is a key event in glomerular disease leading to proteinuria and opening the path toward glomerular scarring. As a consequence, glomerular research strives to discover molecular mechanisms and signaling pathways affecting podocyte health. The hNphs2.Cre mouse model has been a valuable tool to manipulate podocyte-specific genes and to label podocytes for lineage tracing and purification. Here we designed a novel podocyte-specific tricistronic Cre mouse model combining codon improved Cre expression and fluorescent cell labeling with mTomato under the control of the endogenous Nphs2 promoter using viral T2A-peptides. Independent expression of endogenous podocin, codon improved Cre, and mTomato was confirmed by immunofluorescence, fluorescent activated cell sorting and protein analyses. Nphs2pod.T2A.ciCre.T2A.mTomato/wild-type mice developed normally and did not show any signs of glomerular disease or off-target effects under basal conditions and in states of disease. Nphs2pod.T2A.ciCre.T2A.mTomato/wild-type-mediated gene recombination was superior to conventional hNphs2.Cre mice-mediated gene recombination. Last, we compared Cre efficiency in a disease model by mating Nphs2pod.T2A.ciCre.T2A.mTomato/wild-type and hNphs2.Cre mice to Phb2fl/fl mice. The podocyte-specific Phb2 knockout by Nphs2pod.T2A.ciCre.T2A.mTomato/wild-type mice resulted in an aggravated glomerular injury as compared to a podocyte-specific Phb2 gene deletion triggered by hNphs2.Cre. Thus, we generated the first tricistronic podocyte mouse model combining enhanced Cre recombinase efficiency and fluorescent labeling in podocytes without the need for additional matings with conventional reporter mouse lines.
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Affiliation(s)
- Sybille Koehler
- Department II of Internal Medicine and Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany
| | - Sebastian Brähler
- Department II of Internal Medicine and Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany; Department of Pathology and Immunology, Division of Immunobiology, Washington University School of Medicine, St Louis, Missouri, USA
| | - Fabian Braun
- Department II of Internal Medicine and Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany
| | - Henning Hagmann
- Department II of Internal Medicine and Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany
| | - Markus M Rinschen
- Department II of Internal Medicine and Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany; Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases, University of Cologne, Cologne, Germany
| | - Martin R Späth
- Department II of Internal Medicine and Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany
| | - Martin Höhne
- Department II of Internal Medicine and Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany; Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases, University of Cologne, Cologne, Germany; Systems Biology of Ageing Cologne, University of Cologne, Cologne, Germany
| | | | - Bernhard Schermer
- Department II of Internal Medicine and Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany; Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases, University of Cologne, Cologne, Germany; Systems Biology of Ageing Cologne, University of Cologne, Cologne, Germany
| | - Thomas Benzing
- Department II of Internal Medicine and Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany; Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases, University of Cologne, Cologne, Germany; Systems Biology of Ageing Cologne, University of Cologne, Cologne, Germany
| | - Paul T Brinkkoetter
- Department II of Internal Medicine and Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany.
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Yee PTI, Laa Poh C. Impact of genetic changes, pathogenicity and antigenicity on Enterovirus- A71 vaccine development. Virology 2017; 506:121-129. [PMID: 28384566 DOI: 10.1016/j.virol.2017.03.017] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Revised: 03/27/2017] [Accepted: 03/28/2017] [Indexed: 01/17/2023]
Abstract
Enterovirus-A71 (EV-A71) is an etiological agent of the hand, foot and mouth disease (HFMD). EV-A71 infection produces high fever and ulcers in children. Some EV-A71 strains produce severe infections leading to pulmonary edema and death. Although the protective efficacy of the inactivated vaccine (IV) was ≥90% against mild HFMD, there was approximately 80% protection against severe HFMD. The monovalent EV-A71 IV elicits humoral immunity but lacks long-term immunogenicity. Spontaneous mutations of the EV-A71 genome could lead to antigenicity changes and the virus may not be neutralized by antibodies elicited by the IV. A better alternative would be the live attenuated vaccine (LAV) that elicits cellular and humoral immunity. The LAV induces excellent antigenicity and chances of reversion is reduced by presence of multiple mutations which could reduce pathogenicity. Besides CV-A16, outbreaks have been caused by CV-A6 and CV-A10, hence the development of bivalent and trivalent vaccines is required.
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Affiliation(s)
- Pinn Tsin Isabel Yee
- Research Centre for Biomedical Sciences, Sunway University, Bandar Sunway, Kuala Lumpur, Selangor 47500, Malaysia.
| | - Chit Laa Poh
- Research Centre for Biomedical Sciences, Sunway University, Bandar Sunway, Kuala Lumpur, Selangor 47500, Malaysia.
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Yee PTI, Tan KO, Othman I, Poh CL. Identification of molecular determinants of cell culture growth characteristics of Enterovirus 71. Virol J 2016; 13:194. [PMID: 27894305 PMCID: PMC5126835 DOI: 10.1186/s12985-016-0645-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2016] [Accepted: 11/10/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Hand, foot and mouth disease is caused by Enterovirus 71 (EV-A71) and Coxsackieviruses. EV-A71 infection is associated with high fever, rashes and ulcers but more severe symptoms such as cardiopulmonary failure and death have been reported. The lack of vaccines highlighted the urgency of developing preventive agents against EV-A71. The molecular determinants of virulent phenotypes of EV-A71 is unclear. It remains to be investigated if specific molecular determinants would affect the cell culture growth characteristics of the EV-A71 fatal strain in Rhabdomyosarcoma (RD) cells. RESULTS In this study, several genetically modified sub-genotype B4 EV-A71 mutants were constructed by site-directed mutations at positions 158, 475, 486, 487 and 5262 or through partial deletion of the 5'-NTR region (∆ 11 bp from nt 475 to 486) to generate a deletion mutant (PD). EV-A71 mutants 475 and PD caused minimal cytopathic effects, produced lowest viral RNA copy number, viral particles as well as minimal amount of viral protein (VP1) in RD cells when compared to mutants 158, 486, 487 and 5262. CONCLUSIONS The molecular determinants of virulent phenotypes of EV-A71 sub-genotype B4 strain 41 (5865/Sin/000009) were found to differ from the C158 molecular determinant reported for the fatal EV-A71 sub-genotype B1 strain (clinical isolate 237). The site-directed mutations (SDM) introduced at various sites of the cDNA affected growth of the various mutants when compared to the wild type. Lowest viral RNA copy number, minimal number of plaques formed, higher infectious doses required for 50% lethality of RD cells and much reduced VP1 of the EV-A71 sub-genotype B4 strain 41 genome was attained in mutants carrying SDM at position 475 and through partial deletion of 11 bp at the 5'-NTR region.
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Affiliation(s)
- Pinn Tsin Isabel Yee
- Research Centre for Biomedical Sciences, Sunway University, Bandar Sunway, Kuala Lumpur, Selangor 47500 Malaysia
| | - Kuan Onn Tan
- Research Centre for Biomedical Sciences, Sunway University, Bandar Sunway, Kuala Lumpur, Selangor 47500 Malaysia
| | - Iekhsan Othman
- Jeffrey Cheah School of Medicine and Health Sciences, Monash University, Bandar Sunway, Malaysia
| | - Chit Laa Poh
- Research Centre for Biomedical Sciences, Sunway University, Bandar Sunway, Kuala Lumpur, Selangor 47500 Malaysia
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31
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Deshpande JM, Sharma DK, Saxena VK, Shetty SA, Qureshi THIH, Nalavade UP. Genomic characterization of two new enterovirus types, EV-A114 and EV-A121. J Med Microbiol 2016; 65:1465-1471. [PMID: 27902407 DOI: 10.1099/jmm.0.000380] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Enteroviruses cause a variety of illnesses of the gastrointestinal tract, central nervous system and cardiovascular system. Phylogenetic analysis of VP1 sequences has identified 106 different human enteroviruses classified into four enterovirus species within the genus Enterovirus of the family Picornaviridae. It is likely that not all enterovirus types have been discovered. Between September 2013 and October 2014, stool samples of 6274 apparently healthy children of up to 5 years of age residing in Gorakhpur district, Uttar Pradesh, India were screened for enteroviruses. Virus isolates obtained in RD and Hep-2c cells were identified by complete VP1 sequencing. Enteroviruses were isolated from 3042 samples. A total of 87 different enterovirus types were identified. Two isolates with 71 and 74 % nucleotide sequence similarity to all other known enteroviruses were recognized as novel types. In this paper we report identification and complete genome sequence analysis of these two isolates classified as EV-A114 and EV-A121.
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Affiliation(s)
- Jagadish M Deshpande
- Enterovirus Research Centre, Haffkine Institute Compound, AD Marg, Parel, Mumbai, Maharashtra 400012, India
| | - Deepa K Sharma
- Enterovirus Research Centre, Haffkine Institute Compound, AD Marg, Parel, Mumbai, Maharashtra 400012, India
| | - Vinay K Saxena
- Enterovirus Research Centre, Haffkine Institute Compound, AD Marg, Parel, Mumbai, Maharashtra 400012, India
| | - Sushmitha A Shetty
- Enterovirus Research Centre, Haffkine Institute Compound, AD Marg, Parel, Mumbai, Maharashtra 400012, India
| | - Tarique Husain I H Qureshi
- Enterovirus Research Centre, Haffkine Institute Compound, AD Marg, Parel, Mumbai, Maharashtra 400012, India
| | - Uma P Nalavade
- Enterovirus Research Centre, Haffkine Institute Compound, AD Marg, Parel, Mumbai, Maharashtra 400012, India
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32
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Abstract
Cell death is a common outcome of virus infection. In some cases, cell death curbs virus replication. In others, cell death enhances virus dissemination and contributes to tissue injury, exacerbating viral disease. Three forms of cell death are observed following virus infection-apoptosis, necroptosis, and pyroptosis. In this review, I describe the core machinery needed for each of these forms of cell death. Using representative viruses, I highlight how distinct stages of virus replication initiate signaling pathways that elicit these forms of cell death. I also discuss viral strategies to overcome the deleterious effects of cell death on virus propagation and the consequences of cell death for host physiology.
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Affiliation(s)
- Pranav Danthi
- Department of Biology, Indiana University, Bloomington, Indiana 47405;
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33
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A Single Amino Acid Substitution in Poliovirus Nonstructural Protein 2CATPase Causes Conditional Defects in Encapsidation and Uncoating. J Virol 2016; 90:6174-6186. [PMID: 27076638 PMCID: PMC4936127 DOI: 10.1128/jvi.02877-15] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Accepted: 03/28/2016] [Indexed: 12/11/2022] Open
Abstract
The specificity of encapsidation of C-cluster enteroviruses depends on an interaction between capsid proteins and nonstructural protein 2CATPase. In particular, residue N252 of poliovirus 2CATPase interacts with VP3 of coxsackievirus A20, in the context of a chimeric virus. Poliovirus 2CATPase has important roles both in RNA replication and encapsidation. In this study, we searched for additional sites in 2CATPase, near N252, that are required for encapsidation. Accordingly, segments adjacent to N252 were analyzed by combining triple and single alanine mutations to identify residues required for function. Two triple alanine mutants exhibited defects in RNA replication. The remaining two mutations, located in secondary structures in a predicted three-dimensional model of 2CATPase, caused lethal growth phenotypes. Most single alanine mutants, derived from the lethal variants, were either quasi-infectious and yielded variants with wild-type (wt) or temperature-sensitive (ts) growth phenotypes or had a lethal growth phenotype due to defective RNA replication. The K259A mutation, mapping to an α helix in the predicted structure of 2CATPase, resulted in a cold-sensitive virus. In vivo protein synthesis and virus production were strikingly delayed at 33°C relative to the wt, suggesting a defect in uncoating. Studies with a reporter virus indicated that this mutant is also defective in encapsidation at 33°C. Cell imaging confirmed a much-reduced production of K259A mature virus at 33°C relative to the wt. In conclusion, we have for the first time linked a cold-sensitive encapsidation defect in 2CATPase (K259A) to a subsequent delay in uncoating of the virus particle at 33°C during the next cycle of infection. IMPORTANCE Enterovirus morphogenesis, which involves the encapsidation of newly made virion RNA, is a process still poorly understood. Elucidation of this process is important for future drug development for a large variety of diseases caused by these agents. We have previously shown that the specificity of encapsidation of poliovirus and of C-cluster coxsackieviruses, which are prototypes of enteroviruses, is dependent on an interaction of capsid proteins with the multifunctional nonstructural protein 2CATPase. In this study, we have searched for residues in poliovirus 2CATPase, near a presumed capsid-interacting site, important for encapsidation. An unusual cold-sensitive mutant of 2CATPase possessed a defect in encapsidation at 37°C and subsequently in uncoating during the next cycle of infection at 33°C. These studies not only reveal a new site in 2CATPase that is involved in encapsidation but also identify a link between encapsidation and uncoating.
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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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Yee PTI, Poh CL. Development of Novel Vaccines against Enterovirus-71. Viruses 2015; 8:v8010001. [PMID: 26729152 PMCID: PMC4728561 DOI: 10.3390/v8010001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Revised: 12/10/2015] [Accepted: 12/15/2015] [Indexed: 12/30/2022] Open
Abstract
The hand, foot and mouth disease is caused by a group of Enteroviruses such as Enterovirus 71 (EV-A71) and Coxsackievirus CV-A5, CV-A8, and CV-A16. Mild symptoms of EV-A71 infection in children range from high fever, vomiting, rashes and ulcers in mouth but can produce more severe symptoms such as brainstem and cerebellar encephalitis, leading up to cardiopulmonary failure and death. The lack of vaccines and antiviral drugs against EV-A71 highlights the urgency of developing preventive and treatment agents against EV-A71 to prevent further fatalities. Research groups have developed experimental inactivated vaccines, recombinant Viral Protein 1 (VP1) vaccine and virus-like particles (VLPs). The inactivated EV-A71 vaccine is considered the safest viral vaccine, as there will be no reversion to the infectious wild type strain. The recombinant VP1 vaccine is a cost-effective immunogen, while VLPs contain an arrangement of epitopes that can elicit neutralizing antibodies against the virus. As each type of vaccine has its advantages and disadvantages, increased studies are required in the development of such vaccines, whereby high efficacy, long-lasting immunity, minimal risk to those vaccinated, safe and easy production, low cost, dispensing the need for refrigeration and convenient delivery are the major goals in their design.
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Affiliation(s)
- Pinn Tsin Isabel Yee
- Virology Research Group, Vice Chancellor's Office, Sunway University, Bandar Sunway, Kuala Lumpur, Selangor 47500, Malaysia.
| | - Chit Laa Poh
- Virology Research Group, Vice Chancellor's Office, Sunway University, Bandar Sunway, Kuala Lumpur, Selangor 47500, Malaysia.
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A Conserved Inhibitory Mechanism of a Lycorine Derivative against Enterovirus and Hepatitis C Virus. Antimicrob Agents Chemother 2015; 60:913-24. [PMID: 26596952 DOI: 10.1128/aac.02274-15] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2015] [Accepted: 11/19/2015] [Indexed: 02/06/2023] Open
Abstract
Enterovirus 71 (EV71) (Picornaviridae family) and hepatitis C virus (HCV) (Flaviviridae family) are the causative agents of human hand, foot, and mouth disease (HFMD) and hepatitis C, resulting in a severe pandemic involving millions of infections in the Asia-Pacific region and worldwide. The great impact of EV71 and HCV on public health highlights the need to further our understanding of the biology of these two viruses and develop effective therapeutic antivirals. Here, we evaluated a total of 32 lycorine derivatives and demonstrated that 1-acetyllycorine suppressed the proliferation of multiple strains of EV71 in various cells. The results of the drug resistance analysis revealed that 1-acetyllycorine targeted a phenylalanine (F76) in EV71 2A protease (2A(pro)) to stabilize the conformation of a unique zinc finger. Most interestingly, the zinc binding site in EV71 2A(pro) is the exclusive homolog of HCV NS3 among all viruses. Further analysis revealed that 1-acetyllycorine also inhibits HCV with high efficacy, and the mutation on R118 in HCV NS3, which corresponds to F76 in EV71 2A(pro), confers the resistance of HCV to 1-acetyllycorine. These results revealed a conserved mechanism of 1-acetyllycorine against EV71 and HCV through targeting viral proteases. We also documented the significant synergistic anti-EV71 and anti-HCV effects of 1-acetyllycorine with reported inhibitors, supporting potential combination therapy for the treatment of EV71 and HCV infections.
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Jagdeo JM, Dufour A, Fung G, Luo H, Kleifeld O, Overall CM, Jan E. Heterogeneous Nuclear Ribonucleoprotein M Facilitates Enterovirus Infection. J Virol 2015; 89:7064-78. [PMID: 25926642 PMCID: PMC4473559 DOI: 10.1128/jvi.02977-14] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2014] [Accepted: 04/20/2015] [Indexed: 12/15/2022] Open
Abstract
UNLABELLED Picornavirus infection involves a dynamic interplay of host and viral protein interactions that modulates cellular processes to facilitate virus infection and evade host antiviral defenses. Here, using a proteomics-based approach known as TAILS to identify protease-generated neo-N-terminal peptides, we identify a novel target of the poliovirus 3C proteinase, the heterogeneous nuclear ribonucleoproteinM(hnRNP M), a nucleocytoplasmic shuttling RNA-binding protein that is primarily known for its role in pre-mRNA splicing. hnRNPMis cleaved in vitro by poliovirus and coxsackievirus B3 (CVB3) 3C proteinases and is targeted in poliovirus- and CVB3-infected HeLa cells and in the hearts of CVB3-infected mice. hnRNPMrelocalizes from the nucleus to the cytoplasm during poliovirus infection. Finally, depletion of hnRNPMusing small interfering RNA knockdown approaches decreases poliovirus and CVB3 infections in HeLa cells and does not affect poliovirus internal ribosome entry site translation and viral RNA stability. We propose that cleavage of and subverting the function of hnRNPMis a general strategy utilized by picornaviruses to facilitate viral infection. IMPORTANCE Enteroviruses, a member of the picornavirus family, are RNA viruses that cause a range of diseases, including respiratory ailments, dilated cardiomyopathy, and paralysis. Although enteroviruses have been studied for several decades, the molecular basis of infection and the pathogenic mechanisms leading to disease are still poorly understood. Here, we identify hnRNPMas a novel target of a viral proteinase. We demonstrate that the virus subverts the function of hnRNPMand redirects it to a step in the viral life cycle. We propose that cleavage of hnRNPMis a general strategy that picornaviruses use to facilitate infection.
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Affiliation(s)
- Julienne M. Jagdeo
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Antoine Dufour
- Department of Oral Biological and Medical Sciences, University of British Columbia, Vancouver, British Columbia, Canada
| | - Gabriel Fung
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Honglin Luo
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Oded Kleifeld
- School of Biomedical Sciences, Monash University, Victoria, Australia
| | - Christopher M. Overall
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Oral Biological and Medical Sciences, University of British Columbia, Vancouver, British Columbia, Canada
| | - Eric Jan
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, British Columbia, Canada
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Abstract
The Picornaviridae represent a large family of small plus-strand RNA viruses that cause a bewildering array of important human and animal diseases. Morphogenesis is the least-understood step in the life cycle of these viruses, and this process is difficult to study because encapsidation is tightly coupled to genome translation and RNA replication. Although the basic steps of assembly have been known for some time, very few details are available about the mechanism and factors that regulate this process. Most of the information available has been derived from studies of enteroviruses, in particular poliovirus, where recent evidence has shown that, surprisingly, the specificity of encapsidation is governed by a viral protein-protein interaction that does not involve an RNA packaging signal. In this review, we make an attempt to summarize what is currently known about the following topics: (i) encapsidation intermediates, (ii) the specificity of encapsidation (iii), viral and cellular factors that are required for encapsidation, (iv) inhibitors of encapsidation, and (v) a model of enterovirus encapsidation. Finally, we compare some features of picornavirus morphogenesis with those of other plus-strand RNA viruses.
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Discovery of itraconazole with broad-spectrum in vitro antienterovirus activity that targets nonstructural protein 3A. Antimicrob Agents Chemother 2015; 59:2654-65. [PMID: 25691649 DOI: 10.1128/aac.05108-14] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2015] [Accepted: 02/13/2015] [Indexed: 12/18/2022] Open
Abstract
There is currently no approved antiviral therapy for the prophylaxis or treatment of enterovirus infections, which remain a substantial threat to public health. To discover inhibitors that can be immediately repurposed for treatment of enterovirus infections, we developed a high-throughput screening assay that measures the cytopathic effect induced by enterovirus 71 (EV71) to screen an FDA-approved drug library. Itraconazole (ITZ), a triazole antifungal agent, was identified as an effective inhibitor of EV71 replication in the low-micromolar range (50% effective concentrations [EC50s], 1.15 μM). Besides EV71, the compound also inhibited other enteroviruses, including coxsackievirus A16, coxsackievirus B3, poliovirus 1, and enterovirus 68. Study of the mechanism of action by time-of-addition assay and transient-replicon assay revealed that ITZ targeted a step involved in RNA replication or polyprotein processing. We found that the mutations (G5213U and U5286C) conferring the resistance to the compound were in nonstructural protein 3A, and we confirmed the target amino acid substitutions (3A V51L and 3A V75A) using a reverse genetic approach. Interestingly, posaconazole, a new oral azole with a molecular structure similar to that of ITZ, also exhibited anti-EV71 activity. Moreover, ITZ-resistant viruses do not exhibit cross-resistance to posaconazole or the enviroxime-like compound GW5074, which also targets the 3A region, indicating that they may target a specific site(s) in viral genome. Although the protective activity of ITZ or posaconazole (alone or in combination with other antivirals) remains to be assessed in animal models, our findings may represent an opportunity to develop therapeutic interventions for enterovirus infection.
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Martínez-Salas E, Francisco-Velilla R, Fernandez-Chamorro J, Lozano G, Diaz-Toledano R. Picornavirus IRES elements: RNA structure and host protein interactions. Virus Res 2015; 206:62-73. [PMID: 25617758 DOI: 10.1016/j.virusres.2015.01.012] [Citation(s) in RCA: 96] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2014] [Revised: 01/05/2015] [Accepted: 01/12/2015] [Indexed: 01/26/2023]
Abstract
Internal ribosome entry site (IRES) elements were discovered in picornaviruses. These elements are cis-acting RNA sequences that adopt diverse three-dimensional structures and recruit the translation machinery using a 5' end-independent mechanism assisted by a subset of translation initiation factors and various RNA binding proteins termed IRES transacting factors (ITAFs). Many of these factors suffer important modifications during infection including cleavage by picornavirus proteases, changes in the phosphorylation level and/or redistribution of the protein from the nuclear to the cytoplasm compartment. Picornavirus IRES are amongst the most potent elements described so far. However, given their large diversity and complexity, the mechanistic basis of its mode of action is not yet fully understood. This review is focused to describe recent advances on the studies of RNA structure and RNA-protein interactions modulating picornavirus IRES activity.
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Affiliation(s)
- Encarnación Martínez-Salas
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas - Universidad Autónoma de Madrid, Nicolas Cabrera 1, 28049 Madrid, Spain.
| | - Rosario Francisco-Velilla
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas - Universidad Autónoma de Madrid, Nicolas Cabrera 1, 28049 Madrid, Spain
| | - Javier Fernandez-Chamorro
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas - Universidad Autónoma de Madrid, Nicolas Cabrera 1, 28049 Madrid, Spain
| | - Gloria Lozano
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas - Universidad Autónoma de Madrid, Nicolas Cabrera 1, 28049 Madrid, Spain
| | - Rosa Diaz-Toledano
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas - Universidad Autónoma de Madrid, Nicolas Cabrera 1, 28049 Madrid, Spain
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Structural basis for host membrane remodeling induced by protein 2B of hepatitis A virus. J Virol 2015; 89:3648-58. [PMID: 25589659 DOI: 10.1128/jvi.02881-14] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
UNLABELLED The complexity of viral RNA synthesis and the numerous participating factors require a mechanism to topologically coordinate and concentrate these multiple viral and cellular components, ensuring a concerted function. Similarly to all other positive-strand RNA viruses, picornaviruses induce rearrangements of host intracellular membranes to create structures that act as functional scaffolds for genome replication. The membrane-targeting proteins 2B and 2C, their precursor 2BC, and protein 3A appear to be primarily involved in membrane remodeling. Little is known about the structure of these proteins and the mechanisms by which they induce massive membrane remodeling. Here we report the crystal structure of the soluble region of hepatitis A virus (HAV) protein 2B, consisting of two domains: a C-terminal helical bundle preceded by an N-terminally curved five-stranded antiparallel β-sheet that displays striking structural similarity to the β-barrel domain of enteroviral 2A proteins. Moreover, the helicoidal arrangement of the protein molecules in the crystal provides a model for 2B-induced host membrane remodeling during HAV infection. IMPORTANCE No structural information is currently available for the 2B protein of any picornavirus despite it being involved in a critical process in viral factory formation: the rearrangement of host intracellular membranes. Here we present the structure of the soluble domain of the 2B protein of hepatitis A virus (HAV). Its arrangement, both in crystals and in solution under physiological conditions, can help to understand its function and sheds some light on the membrane rearrangement process, a putative target of future antiviral drugs. Moreover, this first structure of a picornaviral 2B protein also unveils a closer evolutionary relationship between the hepatovirus and enterovirus genera within the Picornaviridae family.
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Abstract
Human rhinoviruses (HRV) are the major etiological agents of the common cold and asthma exacerbations, with significant worldwide health and economic impact. Although large-scale population vaccination has proved successful in limiting or even eradicating many viruses, the more than 100 distinct serotypes mean that conventional vaccination is not a feasible strategy to combat HRV. An alternative strategy is to target conserved viral proteins such as the HRV proteases, 2A(pro) and 3C(pro), the focus of this review. Necessary for host cell shutoff, virus replication, and pathogenesis, 2A(pro) and 3C(pro) are clearly viable drug targets, and indeed, 3C(pro) has been successfully targeted for treating the common cold in experimental infection. 2A(pro) and 3C(pro) are crucial for virus replication due to their role in polyprotein processing as well as cleavage of key cellular proteins to inhibit cellular transcription and translation. Intriguingly, the action of the HRV proteases also disrupts nucleocytoplasmic trafficking, contributing to HRV cytopathic effects. Improved understanding of the protease-cell interactions should enable new therapeutic approaches to be identified for drug development.
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Affiliation(s)
- Lora M Jensen
- Faculty of Education, Science, Technology and Mathematics, Centre for Research in Therapeutic Solutions, University of Canberra, 1 Kirinari Street, Bruce, Canberra, ACT, 2601, Australia
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Dong H, Guo HC, Sun SQ. Virus-like particles in picornavirus vaccine development. Appl Microbiol Biotechnol 2014; 98:4321-9. [PMID: 24647496 DOI: 10.1007/s00253-014-5639-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2013] [Revised: 02/20/2014] [Accepted: 02/23/2014] [Indexed: 12/19/2022]
Abstract
Virus-like particles (VLP), which are similar to natural virus particles but do not contain viral genes, have brought about significant breakthroughs in many research fields because of their unique advantages. The ordered repeating epitopes of VLP can induce immunity responses similar to those prompted by natural viral infection; thus, VLP vaccines are regarded as candidate alternatives to whole-virus vaccines. As picornavirus has serious impacts on human and animal health, the development of efficient and safe vaccines is a key endeavor in preventing virus infections. The characteristics of picornavirus capsid proteins allow the development of VLP vaccines. This paper investigates research scenarios and progress on picornavirus VLP vaccines with the aim of providing a reference for researchers focusing on virology and vaccinology.
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Affiliation(s)
- Hu Dong
- State Key Laboratory of Veterinary Etiological Biology, OIE/National Foot and Mouth Disease Reference Laboratory, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Xujiaping 1, Lanzhou, 730046, People's Republic of China
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Strategies for purifying variants of human rhinovirus 14 2C protein. Protein Expr Purif 2013; 95:28-37. [PMID: 24316192 DOI: 10.1016/j.pep.2013.11.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2013] [Revised: 11/14/2013] [Accepted: 11/25/2013] [Indexed: 11/22/2022]
Abstract
The positive strand RNA genome of picornaviruses, including human rhinovirus (HRV), poliovirus (PV) and foot-and-mouth disease virus, is translated immediately into a polyprotein that is cleaved by virally encoded proteinases into 10-13 mature proteins. These include the four proteins required to assemble the viral particle as well as 3D(pol) (the viral RNA polymerase) and 2C, an ATPase and putative helicase. 2C is a protein which is responsible, together with 2B and 3A, for anchoring the replication complexes to membranous structures in the infected cell on which RNA replication takes place. Additionally, expression of 2C and its precursor 2BC in mammalian cells leads to vesicle formation observed in infected cells. 2C is encoded by all picornaviruses; nevertheless, its exact role in viral replication remains unclear. A contributing factor is the absence of structural data for this hydrophobic protein the generation of which has been hampered by an inability to produce soluble and stable material. Here, we compare 2C from several genera and show that the 2C protein has considerable heterogeneity. Using protein structure meta-analysis, we developed models of HRV14 2C that should be useful for mutational analysis. Based on these analyses, we expressed and purified two domains of HRV14 2C using three different protocols and examined the folding by thermal denaturation or (1)H NMR. Both domains were concentrated sufficiently to allow crystal screens or NMR pilot experiments to be performed. This work provides a platform to explore 2C proteins from all picornaviral genera to generate candidates for structural analysis.
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Burrill CP, Westesson O, Schulte MB, Strings VR, Segal M, Andino R. Global RNA structure analysis of poliovirus identifies a conserved RNA structure involved in viral replication and infectivity. J Virol 2013; 87:11670-83. [PMID: 23966409 PMCID: PMC3807356 DOI: 10.1128/jvi.01560-13] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2013] [Accepted: 08/15/2013] [Indexed: 01/06/2023] Open
Abstract
The genomes of RNA viruses often contain RNA structures that are crucial for translation and RNA replication and may play additional, uncharacterized roles during the viral replication cycle. For the picornavirus family member poliovirus, a number of functional RNA structures have been identified, but much of its genome, especially the open reading frame, has remained uncharacterized. We have now generated a global RNA structure map of the poliovirus genome using a chemical probing approach that interrogates RNA structure with single-nucleotide resolution. In combination with orthogonal evolutionary analyses, we uncover several conserved RNA structures in the open reading frame of the viral genome. To validate the ability of our global analyses to identify functionally important RNA structures, we further characterized one of the newly identified structures, located in the region encoding the RNA-dependent RNA polymerase, 3D(pol), by site-directed mutagenesis. Our results reveal that the structure is required for viral replication and infectivity, since synonymous mutants are defective in these processes. Furthermore, these defects can be partially suppressed by mutations in the viral protein 3C(pro), which suggests the existence of a novel functional interaction between an RNA structure in the 3D(pol)-coding region and the viral protein(s) 3C(pro) and/or its precursor 3CD(pro).
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Affiliation(s)
- Cecily P. Burrill
- Tetrad Graduate Program, University of California, San Francisco, California, USA
- Department of Microbiology & Immunology, University of California, San Francisco, California, USA
| | - Oscar Westesson
- Department of Bioengineering, University of California, Berkeley, California, USA
| | - Michael B. Schulte
- Tetrad Graduate Program, University of California, San Francisco, California, USA
- Department of Microbiology & Immunology, University of California, San Francisco, California, USA
| | - Vanessa R. Strings
- Tetrad Graduate Program, University of California, San Francisco, California, USA
- Department of Microbiology & Immunology, University of California, San Francisco, California, USA
| | - Mark Segal
- Department of Epidemiology & Biostatistics, University of California, San Francisco, California, USA
| | - Raul Andino
- Department of Microbiology & Immunology, University of California, San Francisco, California, USA
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An open conformation determined by a structural switch for 2A protease from coxsackievirus A16. Protein Cell 2013; 4:782-92. [PMID: 24026848 DOI: 10.1007/s13238-013-3914-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2013] [Accepted: 09/10/2013] [Indexed: 01/23/2023] Open
Abstract
Coxsackievirus A16 belongs to the family Picornaviridae, and is a major agent of hand-foot-and-mouth disease that infects mostly children, and to date no vaccines or antiviral therapies are available. 2A protease of enterovirus is a nonstructural protein and possesses both self-cleavage activity and the ability to cleave the eukaryotic translation initiation factor 4G. Here we present the crystal structure of coxsackievirus A16 2A protease, which interestingly forms hexamers in crystal as well as in solution. This structure shows an open conformation, with its active site accessible, ready for substrate binding and cleavage activity. In conjunction with a previously reported "closed" state structure of human rhinovirus 2, we were able to develop a detailed hypothesis for the conformational conversion triggered by two "switcher" residues Glu88 and Tyr89 located within the bll2-cII loop. Substrate recognition assays revealed that amino acid residues P1', P2 and P4 are essential for substrate specificity, which was verified by our substrate binding model. In addition, we compared the in vitro cleavage efficiency of 2A proteases from coxsackievirus A16 and enterovirus 71 upon the same substrates by fluorescence resonance energy transfer (FRET), and observed higher protease activity of enterovirus 71 compared to that of coxsackievirus A16. In conclusion, our study shows an open conformation of coxsackievirus A16 2A protease and the underlying mechanisms for conformational conversion and substrate specificity. These new insights should facilitate the future rational design of efficient 2A protease inhibitors.
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Crystal structure of 2A proteinase from hand, foot and mouth disease virus. J Mol Biol 2013; 425:4530-43. [PMID: 23973886 DOI: 10.1016/j.jmb.2013.08.016] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2013] [Revised: 08/07/2013] [Accepted: 08/20/2013] [Indexed: 11/22/2022]
Abstract
EV71 is responsible for several epidemics worldwide; however, the effective antiviral drug is unavailable to date. The 2A proteinase (2A(pro)) of EV71 presents a promising drug target due to its multiple roles in virus replication, inhibition of host protein synthesis and evasion of innate immunity. We determined the crystal structure of EV71 2A(pro) at 1.85Å resolution, revealing that the proteinase maintains a chymotrypsin-like fold. The active site is composed of the catalytic triads C110A, H21 and D39 with the geometry similar to that in other picornaviral 2A(pro), 3C(pro) and serine proteinases. The cI-to-eI2 loop at the N-terminal domain of EV71 2A(pro) adopts a highly stable conformation and contributes to the hydrophilic surface property, which are strikingly different in HRV2 2A(pro) but are similar in CVB4 2A(pro). We identified a hydrophobic motif "LLWL" followed by an acidic motif "DEE" at the C-terminus of EV71 2A(pro). The "LLWL" motif is folded into the β-turn structure that is essential for the positioning of the acidic motif. Our structural and mutagenesis study demonstrated that both the negative charging and the correct positioning of the C-terminus are essential for EV71 replication. Deletion of the "LLWL" motif abrogated the proteolytic activity, indicating that the motif is critical for maintaining the active proteinase conformation. Our findings provide the structural and functional insights into EV71 2A(pro) and establish a framework for structure-based inhibitor design.
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Processing of the VP1/2A junction is not necessary for production of foot-and-mouth disease virus empty capsids and infectious viruses: characterization of "self-tagged" particles. J Virol 2013; 87:11591-603. [PMID: 23966400 DOI: 10.1128/jvi.01863-13] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The foot-and-mouth disease virus (FMDV) capsid protein precursor, P1-2A, is cleaved by 3C(pro) to generate VP0, VP3, VP1, and the peptide 2A. The capsid proteins self-assemble into empty capsid particles or viruses which do not contain 2A. In a cell culture-adapted strain of FMDV (O1 Manisa [Lindholm]), three different amino acid substitutions (E83K, S134C, and K210E) were identified within the VP1 region of the P1-2A precursor compared to the field strain (wild type [wt]). Expression of the O1 Manisa P1-2A (wt or with the S134C substitution in VP1) plus 3C(pro), using a transient expression system, resulted in efficient capsid protein production and self-assembly of empty capsid particles. Removal of the 2A peptide from the capsid protein precursor had no effect on capsid protein processing or particle assembly. However, modification of E83K alone abrogated particle assembly with no apparent effect on protein processing. Interestingly, the K210E substitution, close to the VP1/2A junction, completely blocked processing by 3C(pro) at this cleavage site, but efficient assembly of "self-tagged" empty capsid particles, containing the uncleaved VP1-2A, was observed. These self-tagged particles behaved like the unmodified empty capsids in antigen enzyme-linked immunosorbent assays and integrin receptor binding assays. Furthermore, mutant viruses with uncleaved VP1-2A could be rescued in cells from full-length FMDV RNA transcripts encoding the K210E substitution in VP1. Thus, cleavage of the VP1/2A junction is not essential for virus viability. The production of such engineered self-tagged empty capsid particles may facilitate their purification for use as diagnostic reagents and vaccines.
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Antiviral activities of some synthesized methylsulfanyltriazoloquinazoline derivatives. RESEARCH ON CHEMICAL INTERMEDIATES 2013. [DOI: 10.1007/s11164-013-1177-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Neubauer D, Aumayr M, Gösler I, Skern T. Specificity of human rhinovirus 2A(pro) is determined by combined spatial properties of four cleavage site residues. J Gen Virol 2013; 94:1535-1546. [PMID: 23580429 DOI: 10.1099/vir.0.051201-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The 2A proteinase (2A(pro)) of human rhinoviruses cleaves the virally encoded polyprotein between the C terminus of VP1 and its own N terminus. Poor understanding of the 2A(pro) substrate specificity of this enzyme has hampered progress in developing inhibitors that may serve as antiviral agents. We show here that the 2A(pro) of human rhinovirus (HRV) 1A and 2 (rhinoviruses from genetic group A) cannot self-process at the HRV14 (a genetic group B rhinovirus) cleavage site. When the amino acids in the cleavage site of HRV2 2A(pro) (Ile-Ile-Thr-Thr-Ala*Gly-Pro-Ser-Asp) were singly or doubly replaced with the corresponding HRV14 residues (Asp-Ile-Lys-Ser-Tyr*Gly-Leu-Gly-Pro) at positions from P3 to P2', HRV1A and HRV2 2A(pro) cleavage took place at WT levels. However, when three or more positions of the HRV1A or 2 2A(pro) were substituted (e.g. at P2, P1 and P2'), cleavage in vitro was essentially eliminated. Introduction of the full HRV14 cleavage site into a full-length clone of the HRV1A and transfection of HeLa cells with a transcribed RNA did not give rise to viable virus. In contrast, revertant viruses bearing cysteine at the P1 position or proline at P2' were obtained when an RNA bearing the three inhibitory amino acids was transfected. Reversions in the enzyme affecting substrate specificity were not found in any of the in vivo experiments. Modelling of oligopeptide substrates onto the structure of HRV2 2A(pro) revealed no appreciable differences in residues of HRV2 and HRV14 in the respective substrate binding sites, suggesting that the overall shape of the substrate is important in determining binding efficiency.
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Affiliation(s)
- David Neubauer
- Max F. Perutz Laboratories, Medical University of Vienna, Dr. Bohr-Gasse 9/3, A-1030 Vienna, Austria
| | - Martina Aumayr
- Max F. Perutz Laboratories, Medical University of Vienna, Dr. Bohr-Gasse 9/3, A-1030 Vienna, Austria
| | - Irene Gösler
- Max F. Perutz Laboratories, Medical University of Vienna, Dr. Bohr-Gasse 9/3, A-1030 Vienna, Austria
| | - Tim Skern
- Max F. Perutz Laboratories, Medical University of Vienna, Dr. Bohr-Gasse 9/3, A-1030 Vienna, Austria
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