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Complete Genome Sequence, Molecular Characterization and Phylogenetic Relationships of a Temminck's Stint Calicivirus: Evidence for a New Genus within Caliciviridae Family. Microorganisms 2022; 10:microorganisms10081540. [PMID: 36013958 PMCID: PMC9416405 DOI: 10.3390/microorganisms10081540] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Revised: 07/26/2022] [Accepted: 07/26/2022] [Indexed: 11/16/2022] Open
Abstract
Caliciviridae is a family of viral pathogens that naturally infects vertebrates, including humans, and causes a range of highly contagious infectious diseases. Caliciviruses are not well studied because of the lack of a universal approach to their cultivation; however, the development of molecular genetics and bioinformatics methods can shed light on their genetic architecture and evolutionary relationships. Here, we present and characterize the complete genome sequence of calicivirus isolated from a sandpiper-Temminck's stint (Calidris temminckii), preliminarily named Temminck's stint calicivirus (TsCV). Its genome is a linear, non-segmented, single-stranded (+sense) RNA with genome organization typical of avian caliciviruses. Comparative studies have shown significant divergence of the nucleotide sequence of the TsCV genome, as well as the amino acid sequence of the major capsid protein from all publicly available genomic and protein sequences, with the highest genome sequence similarity to unclassified Ruddy turnstone calicivirus A (43.68%) and the lowest pairwise divergence of the major capsid protein with unclassified goose calicivirus (57.44%). Phylogenetic analysis, as well as a comparative analysis of the homologous proteins, showed evidence of another separate genus within the Caliciviridae family-previously proposed, but not yet accepted by International Committee on Taxonomy of Viruses (ICTV)-the Sanovirus genus, which combines seven previously unclassified genomic sequences of avian caliciviruses, including the newly discovered TsCV, which we propose to consider as a separate species.
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Guo Z, He Q, Yue H, Zhang B, Tang C. Genomic characterization of a RdRp-recombinat nebovirus strain with a novel VP1 genotype. Virus Res 2018; 251:6-13. [PMID: 29709508 DOI: 10.1016/j.virusres.2018.04.016] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Revised: 04/26/2018] [Accepted: 04/26/2018] [Indexed: 01/12/2023]
Abstract
Nebovirus is a new genus within the family Caliciviridae and is a causative agent of calf diarrhea. The limited nebovirus genomic sequences that are currently available has hampered understanding of nebovirus genetic evolution. The aim of the present study was to determine the genomic characterization of strain Bo/LZB-1/17/CH, which was previously identified as being similar to the novel genotype strain Bo/DijonA216/06/FR based on partial capsid sequences. Our results show that the complete RNA genome of strain Bo/LZB-1/17/CH is 7453 nucleotides (nt) in length and shares 79.0%-83.5% nt identity with all available nebovirus genomes in the GenBank database. A phylogenetic analysis based on its complete genome sequence revealed that strain Bo/LZB-1/17/CH clustered into an independent branch. Two interesting characteristics were observed in the genome of strain Bo/LZB-1/17/CH. First, the major capsid protein (VP1) of strain Bo/LZB-1/17/CH shares 96.6% amino acid (aa) identity with strain Bo/DijonA216/06/FR but shares only 75.2%-76.8% aa identity with other nebovirus strains and has an even lower identity in the P2 domain (61.1%-65% aa identity). Second, the RNA-dependent RNA polymerase (RdRp) of strain Bo/LZB-1/17/CH is more closely related to NB-like strains than it is to strain Bo/DijonA216/06/FR, and a recombination event was identified within the 3' end of the RdRp in strain Bo/LZB-1/17/CH. In conclusion, the results in this study indicate that strain Bo/LZB-1/17/CH may represent a novel nebovirus strain. To the best of our knowledge, this is the first description of a recombinant event in nebovirus RdRp.
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Affiliation(s)
- Zijing Guo
- College of Life Science and Technology, Southwest University for Nationalities, Chengdu, China
| | - Qifu He
- College of Life Science and Technology, Southwest University for Nationalities, Chengdu, China
| | - Hua Yue
- College of Life Science and Technology, Southwest University for Nationalities, Chengdu, China
| | - Bin Zhang
- College of Life Science and Technology, Southwest University for Nationalities, Chengdu, China
| | - Cheng Tang
- College of Life Science and Technology, Southwest University for Nationalities, Chengdu, China.
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Structure and Function of Caliciviral RNA Polymerases. Viruses 2017; 9:v9110329. [PMID: 29113097 PMCID: PMC5707536 DOI: 10.3390/v9110329] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Revised: 10/26/2017] [Accepted: 11/02/2017] [Indexed: 11/16/2022] Open
Abstract
Caliciviruses are a leading agent of human and animal gastroenteritis and respiratory tract infections, which are growing concerns in immunocompromised individuals. However, no vaccines or therapeutics are yet available. Since the rapid rate of genetic evolution of caliciviruses is mainly due to the error-prone nature of RNA-dependent RNA polymerase (RdRp), this article focuses on recent studies of the structures and functions of RdRp from caliciviruses. It also provides recent advances in the interactions of RdRp with virion protein genome-linked (VPg) and RNA and the structural and functional features of its precursor.
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Miras M, Miller WA, Truniger V, Aranda MA. Non-canonical Translation in Plant RNA Viruses. FRONTIERS IN PLANT SCIENCE 2017; 8:494. [PMID: 28428795 PMCID: PMC5382211 DOI: 10.3389/fpls.2017.00494] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Accepted: 03/21/2017] [Indexed: 05/03/2023]
Abstract
Viral protein synthesis is completely dependent upon the host cell's translational machinery. Canonical translation of host mRNAs depends on structural elements such as the 5' cap structure and/or the 3' poly(A) tail of the mRNAs. Although many viral mRNAs are devoid of one or both of these structures, they can still translate efficiently using non-canonical mechanisms. Here, we review the tools utilized by positive-sense single-stranded (+ss) RNA plant viruses to initiate non-canonical translation, focusing on cis-acting sequences present in viral mRNAs. We highlight how these elements may interact with host translation factors and speculate on their contribution for achieving translational control. We also describe other translation strategies used by plant viruses to optimize the usage of the coding capacity of their very compact genomes, including leaky scanning initiation, ribosomal frameshifting and stop-codon readthrough. Finally, future research perspectives on the unusual translational strategies of +ssRNA viruses are discussed, including parallelisms between viral and host mRNAs mechanisms of translation, particularly for host mRNAs which are translated under stress conditions.
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Affiliation(s)
- Manuel Miras
- Centro de Edafología y Biología Aplicada del Segura - CSICMurcia, Spain
| | - W. Allen Miller
- Department of Plant Pathology and Microbiology, Iowa State UniversityAmes, IA, USA
| | - Verónica Truniger
- Centro de Edafología y Biología Aplicada del Segura - CSICMurcia, Spain
| | - Miguel A. Aranda
- Centro de Edafología y Biología Aplicada del Segura - CSICMurcia, Spain
- *Correspondence: Miguel A. Aranda
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Olspert A, Hosmillo M, Chaudhry Y, Peil L, Truve E, Goodfellow I. Protein-RNA linkage and posttranslational modifications of feline calicivirus and murine norovirus VPg proteins. PeerJ 2016; 4:e2134. [PMID: 27375966 PMCID: PMC4928471 DOI: 10.7717/peerj.2134] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Accepted: 05/24/2016] [Indexed: 12/01/2022] Open
Abstract
Members of the Caliciviridae family of positive sense RNA viruses cause a wide range of diseases in both humans and animals. The detailed characterization of the calicivirus life cycle had been hampered due to the lack of robust cell culture systems and experimental tools for many of the members of the family. However, a number of caliciviruses replicate efficiently in cell culture and have robust reverse genetics systems available, most notably feline calicivirus (FCV) and murine norovirus (MNV). These are therefore widely used as representative members with which to examine the mechanistic details of calicivirus genome translation and replication. The replication of the calicivirus RNA genome occurs via a double-stranded RNA intermediate that is then used as a template for the production of new positive sense viral RNA, which is covalently linked to the virus-encoded protein VPg. The covalent linkage to VPg occurs during genome replication via the nucleotidylylation activity of the viral RNA-dependent RNA polymerase. Using FCV and MNV, we used mass spectrometry-based approach to identify the specific amino acid linked to the 5′ end of the viral nucleic acid. We observed that both VPg proteins are covalently linked to guanosine diphosphate (GDP) moieties via tyrosine positions 24 and 26 for FCV and MNV respectively. These data fit with previous observations indicating that mutations introduced into these specific amino acids are deleterious for viral replication and fail to produce infectious virus. In addition, we also detected serine phosphorylation sites within the FCV VPg protein with positions 80 and 107 found consistently phosphorylated on VPg-linked viral RNA isolated from infected cells. This work provides the first direct experimental characterization of the linkage of infectious calicivirus viral RNA to the VPg protein and highlights that post-translational modifications of VPg may also occur during the viral life cycle.
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Affiliation(s)
- Allan Olspert
- Faculty of Science, Department of Gene Technology, Tallinn University of Technology , Tallinn , Estonia
| | - Myra Hosmillo
- Division of Virology, Department of Pathology, University of Cambridge , Cambridge , United Kingdom
| | - Yasmin Chaudhry
- Division of Virology, Department of Pathology, University of Cambridge , Cambridge , United Kingdom
| | - Lauri Peil
- Faculty of Science and Technology, Institute of Technology, University of Tartu , Tartu , Estonia
| | - Erkki Truve
- Faculty of Science, Department of Gene Technology, Tallinn University of Technology , Tallinn , Estonia
| | - Ian Goodfellow
- Division of Virology, Department of Pathology, University of Cambridge , Cambridge , United Kingdom
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Royall E, Locker N. Translational Control during Calicivirus Infection. Viruses 2016; 8:104. [PMID: 27104553 PMCID: PMC4848598 DOI: 10.3390/v8040104] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Revised: 04/14/2016] [Accepted: 04/15/2016] [Indexed: 12/22/2022] Open
Abstract
In this review, we provide an overview of the strategies developed by caliciviruses to subvert or regulate the host protein synthesis machinery to their advantage. As intracellular obligate parasites, viruses strictly depend on the host cell resources to produce viral proteins. Thus, many viruses have developed strategies that regulate the function of the host protein synthesis machinery, often leading to preferential translation of viral mRNAs. Caliciviruses lack a 5′ cap structure but instead have a virus-encoded VPg protein covalently linked to the 5′ end of their mRNAs. Furthermore, they encode 2–4 open reading frames within their genomic and subgenomic RNAs. Therefore, they use alternative mechanisms for translation whereby VPg interacts with eukaryotic initiation factors (eIFs) to act as a proteinaceous cap-substitute, and some structural proteins are produced by reinitiation of translation events. This review discusses our understanding of these key mechanisms during caliciviruses infection as well as recent insights into the global regulation of eIF4E activity.
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Affiliation(s)
- Elizabeth Royall
- Faculty of Health and Medical Sciences, School of Biosciences and Medicine, University of Surrey, Guildford GU2 7HX, UK.
| | - Nicolas Locker
- Faculty of Health and Medical Sciences, School of Biosciences and Medicine, University of Surrey, Guildford GU2 7HX, UK.
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Leen EN, Sorgeloos F, Correia S, Chaudhry Y, Cannac F, Pastore C, Xu Y, Graham SC, Matthews SJ, Goodfellow IG, Curry S. A Conserved Interaction between a C-Terminal Motif in Norovirus VPg and the HEAT-1 Domain of eIF4G Is Essential for Translation Initiation. PLoS Pathog 2016; 12:e1005379. [PMID: 26734730 PMCID: PMC4703368 DOI: 10.1371/journal.ppat.1005379] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2015] [Accepted: 12/10/2015] [Indexed: 11/28/2022] Open
Abstract
Translation initiation is a critical early step in the replication cycle of the positive-sense, single-stranded RNA genome of noroviruses, a major cause of gastroenteritis in humans. Norovirus RNA, which has neither a 5´ m7G cap nor an internal ribosome entry site (IRES), adopts an unusual mechanism to initiate protein synthesis that relies on interactions between the VPg protein covalently attached to the 5´-end of the viral RNA and eukaryotic initiation factors (eIFs) in the host cell. For murine norovirus (MNV) we previously showed that VPg binds to the middle fragment of eIF4G (4GM; residues 652–1132). Here we have used pull-down assays, fluorescence anisotropy, and isothermal titration calorimetry (ITC) to demonstrate that a stretch of ~20 amino acids at the C terminus of MNV VPg mediates direct and specific binding to the HEAT-1 domain within the 4GM fragment of eIF4G. Our analysis further reveals that the MNV C terminus binds to eIF4G HEAT-1 via a motif that is conserved in all known noroviruses. Fine mutagenic mapping suggests that the MNV VPg C terminus may interact with eIF4G in a helical conformation. NMR spectroscopy was used to define the VPg binding site on eIF4G HEAT-1, which was confirmed by mutagenesis and binding assays. We have found that this site is non-overlapping with the binding site for eIF4A on eIF4G HEAT-1 by demonstrating that norovirus VPg can form ternary VPg-eIF4G-eIF4A complexes. The functional significance of the VPg-eIF4G interaction was shown by the ability of fusion proteins containing the C-terminal peptide of MNV VPg to inhibit in vitro translation of norovirus RNA but not cap- or IRES-dependent translation. These observations define important structural details of a functional interaction between norovirus VPg and eIF4G and reveal a binding interface that might be exploited as a target for antiviral therapy. Norovirus infections cause acute gastroenteritis and are a growing worldwide problem in human health. A critical early step in infection is translation of the viral RNA genome to produce the proteins needed to assemble new virus particles. In mouse noroviruses (MNV), which provide a useful model for studying human noroviruses, the VPg protein attached to the viral RNA is essential for this process because it interacts with a cellular protein, eIF4G, that is normally involved in initiating protein synthesis from the messenger RNA of host genes. We have used a variety of biochemical and biophysical experiments to measure how well MNV VPg binds to eIF4G and to identify the parts of both proteins that are involved in this interaction. We show that a sequence of about 20 amino acids at one end of MNV VPg–the C terminus– allows it to bind to a well-defined domain within eIF4G (called HEAT-1), and that it may adopt a helical structure when doing so. Our data suggest that this interaction is common to all noroviruses, including types that infect humans. We have also shown that the MNV VPg C-terminal peptide can inhibit norovirus protein synthesis, which raises the possibility that the VPg-eIF4G interaction could be targeted in the design of antiviral drugs.
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Affiliation(s)
- Eoin N Leen
- Department of Life Sciences, Imperial College London, London, United Kingdom
| | - Frédéric Sorgeloos
- Division of Virology, Department of Pathology, University of Cambridge, Addenbrooke's Hospital, Cambridge, United Kingdom
| | - Samantha Correia
- Department of Life Sciences, Imperial College London, London, United Kingdom
| | - Yasmin Chaudhry
- Division of Virology, Department of Pathology, University of Cambridge, Addenbrooke's Hospital, Cambridge, United Kingdom
| | - Fabien Cannac
- Department of Life Sciences, Imperial College London, London, United Kingdom
| | - Chiara Pastore
- Department of Life Sciences, Imperial College London, London, United Kingdom
| | - Yingqi Xu
- Department of Life Sciences, Imperial College London, London, United Kingdom
| | - Stephen C Graham
- Division of Virology, Department of Pathology, University of Cambridge, Addenbrooke's Hospital, Cambridge, United Kingdom
| | - Stephen J Matthews
- Department of Life Sciences, Imperial College London, London, United Kingdom
| | - Ian G Goodfellow
- Division of Virology, Department of Pathology, University of Cambridge, Addenbrooke's Hospital, Cambridge, United Kingdom
| | - Stephen Curry
- Department of Life Sciences, Imperial College London, London, United Kingdom
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Functional expression, monodispersity and conformational changes in the SBMV virus viral VPg on binding TFE. Int J Biol Macromol 2015; 83:178-84. [PMID: 26592780 DOI: 10.1016/j.ijbiomac.2015.11.026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Revised: 11/08/2015] [Accepted: 11/10/2015] [Indexed: 11/21/2022]
Abstract
Southern bean mosaic virus (SBMV) RNA purified from infected plants was used for cloning the viral genome-linked protein (VPg) and was subsequently expressed in Escherichia coli. Circular dichroism (CD), dynamic light scattering (DLS) and saturation transfer difference (STD) by nuclear magnetic resonance (NMR) measurements were employed to determine the degree of monodispersity and to investigate the conformational changes in the absence and presence of trifluoroethanol (TFE) which indicated increased helical content with increasing concentration of TFE. 8-Anilino-1-naphthalenesulfonic acid (ANS) was used as a probe to compare the unfolding regions of the protein before and after addition of TFE. The results indicated that although the TFE concentration influences VPg folding, it does not play a role in nucleotide binding and that the local solvent hydrophobicity causes significant conformational changes.
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