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Ferrer-Orta C, Ferrero DS, Verdaguer N. Dual role of the foot-and-mouth disease virus 3B1 protein in the replication complex: As protein primer and as an essential component to recruit 3Dpol to membranes. PLoS Pathog 2023; 19:e1011373. [PMID: 37126532 PMCID: PMC10174528 DOI: 10.1371/journal.ppat.1011373] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Revised: 05/11/2023] [Accepted: 04/18/2023] [Indexed: 05/02/2023] Open
Abstract
Picornavirus genome replication takes place in specialized intracellular membrane compartments that concentrate viral RNA and proteins as well as a number of host factors that also participate in the process. The core enzyme in the replication machinery is the viral RNA-dependent RNA polymerase (RdRP) 3Dpol. Replication requires the primer protein 3B (or VPg) attached to two uridine molecules. 3B uridylylation is also catalysed by 3Dpol. Another critical interaction in picornavirus replication is that between 3Dpol and the precursor 3AB, a membrane-binding protein responsible for the localization of 3Dpol to the membranous compartments at which replication occurs. Unlike other picornaviruses, the animal pathogen foot-and-mouth disease virus (FMDV), encodes three non-identical copies of the 3B (3B1, 3B2, and 3B3) that could be specialized in different functions within the replication complex. Here, we have used a combination of biophysics, molecular and structural biology approaches to characterize the functional binding of FMDV 3B1 to the base of the palm of 3Dpol. The 1.7 Å resolution crystal structure of the FMDV 3Dpol -3B1 complex shows that 3B1 simultaneously links two 3Dpol molecules by binding at the bottom of their palm subdomains in an almost symmetric way. The two 3B1 contact surfaces involve a combination of hydrophobic and basic residues at the N- (G5-P6, R9; Region I) and C-terminus (R16, L19-P20; Region II) of this small protein. Enzyme-Linked Immunosorbent Assays (ELISA) show that the two 3B1 binding sites play a role in 3Dpol binding, with region II presenting the highest affinity. ELISA assays show that 3Dpol has higher binding affinity for 3B1 than for 3B2 or 3B3. Membrane-based pull-down assays show that 3B1 region II, and to a lesser extent also region I play essential roles in mediating the interaction of 3AB with the polymerase and its recruitment to intracellular membranes.
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Affiliation(s)
- Cristina Ferrer-Orta
- Instituto de Biología Molecular de Barcelona. Consejo Superior de Investigaciones Científicas (IBMB-CSIC), Barcelona, Spain
| | - Diego S Ferrero
- Instituto de Biología Molecular de Barcelona. Consejo Superior de Investigaciones Científicas (IBMB-CSIC), Barcelona, Spain
| | - Nuria Verdaguer
- Instituto de Biología Molecular de Barcelona. Consejo Superior de Investigaciones Científicas (IBMB-CSIC), Barcelona, Spain
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VPg Impact on Ryegrass Mottle Virus Serine-like 3C Protease Proteolysis and Structure. Int J Mol Sci 2023; 24:ijms24065347. [PMID: 36982419 PMCID: PMC10048871 DOI: 10.3390/ijms24065347] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Revised: 03/03/2023] [Accepted: 03/09/2023] [Indexed: 03/16/2023] Open
Abstract
Sobemoviruses encode serine-like 3C proteases (Pro) that participate in the processing and maturation of other virus-encoded proteins. Its cis and trans activity is mediated by the naturally unfolded virus-genome-linked protein (VPg). Nuclear magnetic resonance studies show a Pro–VPg complex interaction and VPg tertiary structure; however, information regarding structural changes of the Pro–VPg complex during interaction is lacking. Here, we solved a full Pro–VPg 3D structure of ryegrass mottle virus (RGMoV) that demonstrates the structural changes in three different conformations due to VPg interaction with Pro. We identified a unique site of VPg interaction with Pro that was not observed in other sobemoviruses, and observed different conformations of the Pro β2 barrel. This is the first report of a full plant Pro crystal structure with its VPg cofactor. We also confirmed the existence of an unusual previously unmapped cleavage site for sobemovirus Pro in the transmembrane domain: E/A. We demonstrated that RGMoV Pro in cis activity is not regulated by VPg and that in trans, VPg can also mediate Pro in free form. Additionally, we observed Ca2+ and Zn2+ inhibitory effects on the Pro cleavage activity.
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Revisiting Viral RNA-Dependent RNA Polymerases: Insights from Recent Structural Studies. Viruses 2022; 14:v14102200. [PMID: 36298755 PMCID: PMC9612308 DOI: 10.3390/v14102200] [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: 08/31/2022] [Revised: 09/29/2022] [Accepted: 10/02/2022] [Indexed: 11/07/2022] Open
Abstract
RNA-dependent RNA polymerases (RdRPs) represent a distinctive yet versatile class of nucleic acid polymerases encoded by RNA viruses for the replication and transcription of their genome. The structure of the RdRP is comparable to that of a cupped right hand consisting of fingers, palm, and thumb subdomains. Despite the presence of a common structural core, the RdRPs differ significantly in the mechanistic details of RNA binding and polymerization. The present review aims at exploring these incongruities in light of recent structural studies of RdRP complexes with diverse cofactors, RNA moieties, analogs, and inhibitors.
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Eruera AR, McSweeney AM, McKenzie-Goldsmith GM, Ward VK. Protein Nucleotidylylation in +ssRNA Viruses. Viruses 2021; 13:1549. [PMID: 34452414 PMCID: PMC8402628 DOI: 10.3390/v13081549] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 07/30/2021] [Accepted: 08/02/2021] [Indexed: 12/22/2022] Open
Abstract
Nucleotidylylation is a post-transcriptional modification important for replication in the picornavirus supergroup of RNA viruses, including members of the Caliciviridae, Coronaviridae, Picornaviridae and Potyviridae virus families. This modification occurs when the RNA-dependent RNA polymerase (RdRp) attaches one or more nucleotides to a target protein through a nucleotidyl-transferase reaction. The most characterized nucleotidylylation target is VPg (viral protein genome-linked), a protein linked to the 5' end of the genome in Caliciviridae, Picornaviridae and Potyviridae. The nucleotidylylation of VPg by RdRp is a critical step for the VPg protein to act as a primer for genome replication and, in Caliciviridae and Potyviridae, for the initiation of translation. In contrast, Coronaviridae do not express a VPg protein, but the nucleotidylylation of proteins involved in replication initiation is critical for genome replication. Furthermore, the RdRp proteins of the viruses that perform nucleotidylylation are themselves nucleotidylylated, and in the case of coronavirus, this has been shown to be essential for viral replication. This review focuses on nucleotidylylation within the picornavirus supergroup of viruses, including the proteins that are modified, what is known about the nucleotidylylation process and the roles that these modifications have in the viral life cycle.
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Affiliation(s)
| | | | | | - Vernon K. Ward
- Department of Microbiology & Immunology, School of Biomedical Sciences, University of Otago, PO Box 56, Dunedin 9054, New Zealand; (A.-R.E.); (A.M.M.); (G.M.M.-G.)
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Noroviruses-The State of the Art, Nearly Fifty Years after Their Initial Discovery. Viruses 2021; 13:v13081541. [PMID: 34452406 PMCID: PMC8402810 DOI: 10.3390/v13081541] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 07/06/2021] [Accepted: 07/31/2021] [Indexed: 12/11/2022] Open
Abstract
Human noroviruses are recognised as the major global cause of viral gastroenteritis. Here, we provide an overview of notable advances in norovirus research and provide a short recap of the novel model systems to which much of the recent progress is owed. Significant advances include an updated classification system, the description of alternative virus-like protein morphologies and capsid dynamics, and the further elucidation of the functions and roles of various viral proteins. Important milestones include new insights into cell tropism, host and microbial attachment factors and receptors, interactions with the cellular translational apparatus, and viral egress from cells. Noroviruses have been detected in previously unrecognised hosts and detection itself is facilitated by improved analytical techniques. New potential transmission routes and/or viral reservoirs have been proposed. Recent in vivo and in vitro findings have added to the understanding of host immunity in response to norovirus infection, and vaccine development has progressed to preclinical and even clinical trial testing. Ongoing development of therapeutics includes promising direct-acting small molecules and host-factor drugs.
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Katayama K. [Review Norovirus]. Uirusu 2020; 70:117-128. [PMID: 34544926 DOI: 10.2222/jsv.70.117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Noroviruses commonly cause infectious gastroenteritis and massive food poisoning. There is an urgent need to elucidate the infection mechanism of noroviruses and to develop vaccines and therapeutic drugs. In addition to human disease, noroviruses have been implicated in animal disease. Noroviruses that cause murine diseases can be propagated in strained cultured cells, and for many years, murine norovirus has been used as a model for human noroviruses that could not be propagated in cultured cells. That model and advances in technology have been instrumental in basic studies of noroviruses. From structural biology, noroviruses undergo dynamic shape changes to improve their infectivity when they infect cells. New culture techniques have made human intestinal organoids available for studying the mechanisms of pathogenic expression of human noroviruses in the intestinal tract, mechanisms of infection growth, and the search for receptor molecules. Vaccines and antivirals using human intestinal organoids are under active development, and some are already in clinical trials. In this paper, I review the latest research results, vaccine development, and other advances from the history of norovirus discovery.
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Affiliation(s)
- Kazuhiko Katayama
- Laboratory of Viral Infection I, Department of Infection Control and Immunology, Ōmura Satoshi Memorial Institute & Graduate School of Infection Control Sciences, Kitasato University
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Smertina E, Urakova N, Strive T, Frese M. Calicivirus RNA-Dependent RNA Polymerases: Evolution, Structure, Protein Dynamics, and Function. Front Microbiol 2019; 10:1280. [PMID: 31244803 PMCID: PMC6563846 DOI: 10.3389/fmicb.2019.01280] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Accepted: 05/22/2019] [Indexed: 12/11/2022] Open
Abstract
The Caliciviridae are viruses with a positive-sense, single-stranded RNA genome that is packaged into an icosahedral, environmentally stable protein capsid. The family contains five genera (Norovirus, Nebovirus, Sapovirus, Lagovirus, and Vesivirus) that infect vertebrates including amphibians, reptiles, birds, and mammals. The RNA-dependent RNA polymerase (RdRp) replicates the genome of RNA viruses and can speed up evolution due to its error-prone nature. Studying calicivirus RdRps in the context of genuine virus replication is often hampered by a lack of suitable model systems. Enteric caliciviruses and RHDV in particular are notoriously difficult to propagate in cell culture; therefore, molecular studies of replication mechanisms are challenging. Nevertheless, research on recombinant proteins has revealed several unexpected characteristics of calicivirus RdRps. For example, the RdRps of RHDV and related lagoviruses possess the ability to expose a hydrophobic motif, to rearrange Golgi membranes, and to copy RNA at unusually high temperatures. This review is focused on the structural dynamics, biochemical properties, kinetics, and putative interaction partners of these RdRps. In addition, we discuss the possible existence of a conserved but as yet undescribed structural element that is shared amongst the RdRps of all caliciviruses.
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Affiliation(s)
- Elena Smertina
- Commonwealth Scientific and Industrial Research Organisation, Health and Biosecurity, Canberra, ACT, Australia
- Faculty of Science and Technology, University of Canberra, Canberra, ACT, Australia
| | - Nadya Urakova
- Department of Entomology, Pennsylvania State University, University Park, PA, United States
| | - Tanja Strive
- Commonwealth Scientific and Industrial Research Organisation, Health and Biosecurity, Canberra, ACT, Australia
- Invasive Animals Cooperative Research Centre, University of Canberra, Canberra, ACT, Australia
| | - Michael Frese
- Faculty of Science and Technology, University of Canberra, Canberra, ACT, Australia
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Han KR, Lee JH, Kotiguda GG, Jung KH, Chung MS, Kang S, Hwang S, Kim KH. Nucleotide triphosphatase and RNA chaperone activities of murine norovirus NS3. J Gen Virol 2018; 99:1482-1493. [PMID: 30265237 DOI: 10.1099/jgv.0.001151] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Modulation of RNA structure is essential in the life cycle of RNA viruses. Immediate replication upon infection requires RNA unwinding to ensure that RNA templates are not in intra- or intermolecular duplex forms. The calicivirus NS3, one of the highly conserved nonstructural (NS) proteins, has conserved motifs common to helicase superfamily 3 among six genogroups. However, its biological functions are not fully understood. In this study we report the oligomeric state and the nucleotide triphosphatase (NTPase) and RNA chaperone activities of the recombinant full-length NS3 derived from murine norovirus (MNV). The MNV NS3 has an Mg2+-dependent NTPase activity, and site-directed mutagenesis of the conserved NTPase motifs blocked enzyme activity and viral replication in cells. Further, the NS3 was found via fluorescence resonance energy transfer (FRET)-based assays to destabilize double-stranded RNA in the presence of Mg2+ or Mn2+ in an NTP-independent manner. However, the RNA destabilization activity was not affected by mutagenesis of the conserved motifs of NTPase. These results reveal that the MNV NS3 has an NTPase-independent RNA chaperone-like activity, and that a FRET-based RNA destabilization assay has the potential to identify new antiviral drugs targeting NS3.
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Affiliation(s)
- Kang Rok Han
- 1Department of Biotechnology and Bioinformatics, Korea University, Sejong 339-700, Republic of Korea.,†Present address: Konkuk University, Seoul, Republic of Korea
| | - Ji-Hye Lee
- 1Department of Biotechnology and Bioinformatics, Korea University, Sejong 339-700, Republic of Korea
| | - Giri Gowda Kotiguda
- 1Department of Biotechnology and Bioinformatics, Korea University, Sejong 339-700, Republic of Korea.,‡Present address: Department of Biochemistry, Indian Institute of Science, Bangalore 560012, India
| | - Kyoung Ho Jung
- 1Department of Biotechnology and Bioinformatics, Korea University, Sejong 339-700, Republic of Korea
| | - Mi Sook Chung
- 2Department of Food and Nutrition, Duksung Women's University, Seoul 132-714, Republic of Korea
| | - Soowon Kang
- 3Department of Pathology, The University of Chicago, Chicago, IL 60637, USA
| | - Seungmin Hwang
- 3Department of Pathology, The University of Chicago, Chicago, IL 60637, USA
| | - Kyung Hyun Kim
- 1Department of Biotechnology and Bioinformatics, Korea University, Sejong 339-700, Republic of Korea
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