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Li L, Zhao J, Shao Y, Ma J, Lu T, Xu L. MK-0608 inhibits in vitro and in vivo RNA replication of infectious pancreatic necrosis virus. FISH & SHELLFISH IMMUNOLOGY 2024; 151:109732. [PMID: 38944252 DOI: 10.1016/j.fsi.2024.109732] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2024] [Revised: 06/16/2024] [Accepted: 06/26/2024] [Indexed: 07/01/2024]
Abstract
Infectious pancreatic necrosis virus (IPNV) is an important pathogen that is threatening the worldwide salmon and trout industry. But there is no therapeutic drug available for now. In this study, we demonstrate that MK-0608 is highly efficient against IPNV and low cytotoxic, with a 50 % effective concentration (EC50) of 0.20 μM and selectivity index (SI) of about 268. Time of addition assay illustrated that MK-0608 targeted the early stage of IPNV life cycle. Furthermore, we found that MK-0608 blocked IPNV attachment on the premise of sufficient pre-incubation time but MK-0608 did not influence viral internalization and release. MK-0608 could inhibit IPNV genome synthesis, and combination with ribavirin enhanced the inhibition effect, which might be functional via binding to IPNV RNA dependent RNA polymerase (RdRp), which was predicted by using molecular docking methods. In vivo test showed that IPNV was extremely suppressed in the rainbow trout (Oncorhynchus mykiss) with one single dose of MK-0608, and the higher dosage of 50 mg/kg could cause 3 log decrease of IPNV loads in fish tissues.
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Affiliation(s)
- Linfang Li
- University of Shanghai Ocean University, College of Fisheries and Life Sciences, Shanghai, China; Department of Aquatic Animal Diseases and Control, Heilongjiang River Fisheries Research Institute, Chinese Academy of Fishery Sciences, China
| | - Jingzhuang Zhao
- Department of Aquatic Animal Diseases and Control, Heilongjiang River Fisheries Research Institute, Chinese Academy of Fishery Sciences, China; Key Laboratory of Aquatic Animal Diseases and Immune Technology of Heilongjiang Province, Harbin, China
| | - Yizhi Shao
- Department of Aquatic Animal Diseases and Control, Heilongjiang River Fisheries Research Institute, Chinese Academy of Fishery Sciences, China; Key Laboratory of Aquatic Animal Diseases and Immune Technology of Heilongjiang Province, Harbin, China
| | - Jie Ma
- Department of Fish and Wildlife Sciences, University of Idaho, USA
| | - Tongyan Lu
- Department of Aquatic Animal Diseases and Control, Heilongjiang River Fisheries Research Institute, Chinese Academy of Fishery Sciences, China; Key Laboratory of Aquatic Animal Diseases and Immune Technology of Heilongjiang Province, Harbin, China.
| | - Liming Xu
- Department of Aquatic Animal Diseases and Control, Heilongjiang River Fisheries Research Institute, Chinese Academy of Fishery Sciences, China; Key Laboratory of Aquatic Animal Diseases and Immune Technology of Heilongjiang Province, Harbin, China.
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Wang W, He X, Zhang Y, Qiao Y, Shi J, Chen R, Chen J, Xiang Y, Wang Z, Chen G, Huang J, Huang T, Wei T, Mo M, Wei P. Analysis of the global origin, evolution and transmission dynamics of the emerging novel variant IBDV (A2dB1b): The accumulation of critical aa-residue mutations and commercial trade contributes to the emergence and transmission of novel variants. Transbound Emerg Dis 2022; 69:e2832-e2851. [PMID: 35717667 DOI: 10.1111/tbed.14634] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Revised: 06/15/2022] [Accepted: 06/15/2022] [Indexed: 12/18/2022]
Abstract
The Chinese IBDV novel variant (nvIBDV), belonging to the genotype A2dB1b, an emerging pathotype that can cause subclinical disease with severe, prolonged immunosuppression, poses a new threat to the poultry industry. The process of the global origin, evolution and transmission dynamics of nvIBDV, however, is poorly understood. In this study, phylogenetic trees, site substitutions of amino acid (aa) and highly accurate protein structure modelling, selection pressure, evolutionary and transmission dynamics of nvIBDV were analysed. Interestingly, nvIBDV was classified into the same genogroup with the early US antigenic variants (avIBDV) but in a new lineage with a markedly different and specific pattern of 17 aa-residual substitutions: 13 in VP2 (77D, 213N, 221K, 222T, 249K, 252I, 253Q, 254N, 284A, 286I, 299S, 318D and 323E) and four in VP1 (141I, 163V, 240E and 508K). Importantly, the aa-residues 299S and 163V may play a key role in cell binding and polymerase activity, respectively. The effective population size of the circulating avIBDV experienced two growth phases, respectively, in the years 1999-2007 (in North America) and 2015-2021 (in Asia), which is consistent with the observed trend of the epidemic outbreaks. The most recent common ancestor (tMRCA) of avIBDV most first originated in the USA and was dated around the 1970s. After its emergence, the ancestor virus of this group probably spread to China around the 1990s and the variants experienced a long-term latent circulation with the accumulation of several critical aa-residue mutations in VP2 until re-emerging in 2016. At present, central China has become the epicentre of nvIBDV spread to other parts of China and Asian countries. Importantly, a strong correlation seems to exist between the transmission patterns of virus and the flow of commercial trade of live poultry and products. These findings provide important insights into the origin, evolution and transmission of the nvIBDV and will assist in the development of programs for control strategies for these emerging viruses.
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Affiliation(s)
- Weiwei Wang
- Institute for Poultry Science and Health, Guangxi University, Nanning, China
| | - Xiumiao He
- Guangxi Key Laboratory for Polysaccharide Materials and Modifications, School of Marine Sciences and Biotechnology, Guangxi University for Nationalities, Nanning, China
| | - Yan Zhang
- Institute for Poultry Science and Health, Guangxi University, Nanning, China
| | - Yuanzheng Qiao
- Institute for Poultry Science and Health, Guangxi University, Nanning, China
| | - Jun Shi
- Institute for Poultry Science and Health, Guangxi University, Nanning, China
| | - Rui Chen
- Guangxi Key Laboratory for Polysaccharide Materials and Modifications, School of Marine Sciences and Biotechnology, Guangxi University for Nationalities, Nanning, China
| | - Jinnan Chen
- Guangxi Key Laboratory for Polysaccharide Materials and Modifications, School of Marine Sciences and Biotechnology, Guangxi University for Nationalities, Nanning, China
| | - Yanhua Xiang
- Guangxi Key Laboratory for Polysaccharide Materials and Modifications, School of Marine Sciences and Biotechnology, Guangxi University for Nationalities, Nanning, China
| | - Zhiyuan Wang
- Guangxi Key Laboratory for Polysaccharide Materials and Modifications, School of Marine Sciences and Biotechnology, Guangxi University for Nationalities, Nanning, China
| | - Guo Chen
- Institute for Poultry Science and Health, Guangxi University, Nanning, China
| | - Jianni Huang
- Institute for Poultry Science and Health, Guangxi University, Nanning, China
| | - Teng Huang
- Institute for Poultry Science and Health, Guangxi University, Nanning, China
| | - Tianchao Wei
- Institute for Poultry Science and Health, Guangxi University, Nanning, China
| | - Meilan Mo
- Institute for Poultry Science and Health, Guangxi University, Nanning, China
| | - Ping Wei
- Institute for Poultry Science and Health, Guangxi University, Nanning, China
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González-Catrilelbún S, Cartagena J, Vargas D, Breguel-Serrano P, Sandino AM, Rivas-Aravena A. The RNA-dependent RNA polymerase of the infectious pancreatic necrosis virus is linked to viral mRNA acting as a cap substitute. J Gen Virol 2022; 103. [DOI: 10.1099/jgv.0.001729] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The infectious pancreatic necrosis virus (IPNV) is responsible for significant economic losses in the aquaculture industry. It is an unenveloped virus with an icosahedral capsid. Its viral genome comprises two dsRNA segments, A and B. Segment A contains a small ORF, which encodes VP5, and a large ORF, which encodes a polyprotein that generates the structural proteins and the viral protease. Segment B encodes the RNA-dependent RNA polymerase (RdRp), called VP1 in this free form, or Vpg when it covalently attaches to the viral RNA. The viral genome does not have cap or poly(A). Instead, each 5′ end is linked to the Vpg. Recently, we demonstrated that mRNA-A contains an internal ribosome entry site (IRES) to command polyprotein synthesis. However, the presence of Vpg on IPNV mRNAs and its impact on cellular translation has not been investigated. This research demonstrates that IPNV mRNAs are linked to Vpg and that this protein inhibits cap-dependent translation on infected cells. Also, it is demonstrated that Vpg interacts with eIF4E and that rapamycin treatment partially diminishes the viral protein synthesis. In addition, we determined that an IRES does not command translation of IPNV mRNA-B. We show that VPg serves as a cap substitute during the initiation of IPNV translation, contributing to understanding the replicative cycle of Birnaviruses. Our results indicate that the viral protein VP1/Vpg is multifunctional, having a significant role during IPNV RNA synthesis as the RdRp and the primer for IPNV RNA synthesis and translation as the viral protein genome, acting as a cap substitute.
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Affiliation(s)
| | - Julio Cartagena
- Laboratorio de Virología, Centro de Biotecnología Acuícola, Universidad de Santiago de Chile, Santiago, Chile
| | - Deborah Vargas
- Laboratorio de Virología, Centro de Biotecnología Acuícola, Universidad de Santiago de Chile, Santiago, Chile
| | - Pamela Breguel-Serrano
- Laboratorio de Virología, Facultad de Medicina y Ciencia, Universidad San Sebastián, Santiago, Chile
| | - Ana María Sandino
- Laboratorio de Virología, Centro de Biotecnología Acuícola, Universidad de Santiago de Chile, Santiago, Chile
| | - Andrea Rivas-Aravena
- Laboratorio de Virología, Facultad de Medicina y Ciencia, Universidad San Sebastián, Santiago, Chile
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The Infectious Pancreatic Necrosis Virus (IPNV) and its Virulence Determinants: What is Known and What Should be Known. Pathogens 2020; 9:pathogens9020094. [PMID: 32033004 PMCID: PMC7168660 DOI: 10.3390/pathogens9020094] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2019] [Revised: 01/25/2020] [Accepted: 01/31/2020] [Indexed: 12/30/2022] Open
Abstract
Infectious pancreatic necrosis (IPN) is a disease of great concern in aquaculture, mainly among salmonid farmers, since losses in salmonid fish—mostly very young rainbow trout (Salmo gairdnery) fry and Atlantic salmon (Salmo salar) post-smolt—frequently reach 80–90% of stocks. The virus causing the typical signs of the IPN disease in salmonids, named infectious pancreatic necrosis virus (IPNV), has also been isolated from other fish species either suffering related diseases (then named IPNV-like virus) or asymptomatic; the general term aquabirnavirus is used to encompass all these viruses. Aquabirnaviruses are non-enveloped, icosahedral bisegmented dsRNA viruses, whose genome codifies five viral proteins, three of which are structural, and one of them is an RNA-dependent RNA polymerase. Due to the great importance of the disease, there have been great efforts to find a way to predict the level of virulence of IPNV isolates. The viral genome and proteins have been the main focus of research. However, to date such a reliable magic marker has not been discovered. This review describes the processes followed for decades in the attempts to discover the viral determinants of virulence, and to help the reader understand how viral components can be involved in virulence modulation in vitro and in vivo. There is also a brief description of the disease, of host defenses, and of the molecular structure and function of the virus and its viral components.
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Rivas-Aravena A, Muñoz P, Jorquera P, Diaz A, Reinoso C, González-Catrilelbún S, Sandino AM. Study of RNA-A Initiation Translation of The Infectious Pancreatic Necrosis Virus. Virus Res 2017; 240:121-129. [PMID: 28743463 DOI: 10.1016/j.virusres.2017.07.014] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Revised: 06/08/2017] [Accepted: 07/12/2017] [Indexed: 01/24/2023]
Abstract
The infectious pancreatic necrosis virus (IPNV) is a salmonid pathogen that causes significant economic losses to the aquaculture industry. IPNV is a non-enveloped virus containing two uncapped and non-polyadenylated double strand RNA genomic segments, RNA-A and RNA-B. The viral protein Vpg is covalently attached to the 5' end of both segments. There is little knowledge about its viral cycle, particularly about the translation of the RNAs. Through experiments using mono and bicistronic reporters, in this work we show that the 120-nucleotide-long 5'-UTR of RNA-A contains an internal ribosome entry site (IRES) that functions efficiently both in vitro and in salmon cells. IRES activity is strongly dependent on temperature. Also, the IRES structure is confined to the 5'UTR and is not affected by the viral coding sequence. This is the first report of IRES activity in a fish virus and can give us tools to generate antivirals to attack the virus without affecting fish directly.
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Affiliation(s)
- Andrea Rivas-Aravena
- Comisión Chilena de Energía Nuclear, Departamento de Aplicaciones Nucleares, Laboratorio de Radiobiología Celular y Molecular. Nueva Bilbao 12501, Las Condes, Santiago, Chile; Universidad San Sebastián, Facultad de Ciencias, Lota 2465, Providencia, Santiago, Chile.
| | - Patricio Muñoz
- Universidad de Santiago de Chile, Centro de Biotecnología Acuícola, Laboratorio de Virología,Av. Bernardo O'Higgins 3303, Estación Central, Santiago, Chile
| | - Patricia Jorquera
- Universidad de Santiago de Chile, Centro de Biotecnología Acuícola, Laboratorio de Virología,Av. Bernardo O'Higgins 3303, Estación Central, Santiago, Chile
| | - Alvaro Diaz
- Universidad de Santiago de Chile, Centro de Biotecnología Acuícola, Laboratorio de Virología,Av. Bernardo O'Higgins 3303, Estación Central, Santiago, Chile
| | - Claudia Reinoso
- Universidad de Santiago de Chile, Centro de Biotecnología Acuícola, Laboratorio de Virología,Av. Bernardo O'Higgins 3303, Estación Central, Santiago, Chile
| | - Sebastián González-Catrilelbún
- Comisión Chilena de Energía Nuclear, Departamento de Aplicaciones Nucleares, Laboratorio de Radiobiología Celular y Molecular. Nueva Bilbao 12501, Las Condes, Santiago, Chile; Universidad de Santiago de Chile, Centro de Biotecnología Acuícola, Laboratorio de Virología,Av. Bernardo O'Higgins 3303, Estación Central, Santiago, Chile
| | - Ana María Sandino
- Universidad de Santiago de Chile, Centro de Biotecnología Acuícola, Laboratorio de Virología,Av. Bernardo O'Higgins 3303, Estación Central, Santiago, Chile.
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Ferrero DS, Buxaderas M, Rodríguez JF, Verdaguer N. The Structure of the RNA-Dependent RNA Polymerase of a Permutotetravirus Suggests a Link between Primer-Dependent and Primer-Independent Polymerases. PLoS Pathog 2015; 11:e1005265. [PMID: 26625123 PMCID: PMC4666646 DOI: 10.1371/journal.ppat.1005265] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Accepted: 10/19/2015] [Indexed: 11/18/2022] Open
Abstract
Thosea asigna virus (TaV), an insect virus belonging to the Permutatetraviridae family, has a positive-sense single-stranded RNA (ssRNA) genome with two overlapping open reading frames, encoding for the replicase and capsid proteins. The particular TaV replicase includes a structurally unique RNA-dependent RNA polymerase (RdRP) with a sequence permutation in the palm sub-domain, where the active site is anchored. This non-canonical arrangement of the RdRP palm is also found in double-stranded RNA viruses of the Birnaviridae family. Both virus families also share a conserved VPg sequence motif at the polymerase N-terminus which in birnaviruses appears to be used to covalently link a fraction of the replicase molecules to the 5’-end of the genomic segments. Birnavirus VPgs are presumed to be used as primers for replication initiation. Here we have solved the crystal structure of the TaV RdRP, the first non-canonical RdRP of a ssRNA virus, in its apo- form and bound to different substrates. The enzyme arranges as a stable dimer maintained by mutual interactions between the active site cleft of one molecule and the flexible N-terminal tail of the symmetrically related RdRP. The latter, partially mimicking the RNA template backbone, is involved in regulating the polymerization activity. As expected from previous sequence-based bioinformatics predictions, the overall architecture of the TaV enzyme shows important resemblances with birnavirus polymerases. In addition, structural comparisons and biochemical analyses reveal unexpected similarities between the TaV RdRP and those of Flaviviruses. In particular, a long loop protruding from the thumb domain towards the central enzyme cavity appears to act as a platform for de novo initiation of RNA replication. Our findings strongly suggest an unexpected evolutionary relationship between the RdRPs encoded by these distant ssRNA virus groups. RNA dependent RNA polymerases (RdRPs) are the catalytic components of the RNA replication and transcription machineries, and thus central players in the life cycle of RNA viruses. The in-depth understanding of both the structure and regulation of viral RdRPs displaying different replication-transcription strategies might provide essential clues for an effective control of virus propagation. The characterization of the first non-canonical RdRP of a positive-stranded RNA virus, the permutotetravirus Thosea asigna virus, has unveiled two essential elements controlling polymerization activity: (i) the protein N-terminus that invades the central cleft of the neighboring RdRP molecule, thus stabilizing a dimeric form of the enzyme with partially occluded template binding channels; and (ii) a long loop protruding towards the catalytic cavity which harbors the binding site of incoming nucleotides, thus providing a platform for de novo replication initiation. The close structural and functional resemblance between this enzyme and flaviviral RdRPs strongly suggests the existence of an unexpected evolutionary link between these two distant virus groups.
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Affiliation(s)
- Diego S. Ferrero
- Institut de Biologia Molecular de Barcelona, CSIC, Parc Científic de Barcelona, Barcelona, Spain
- Centro Nacional de Biotecnología, CSIC, Madrid, Spain
| | - Mònica Buxaderas
- Institut de Biologia Molecular de Barcelona, CSIC, Parc Científic de Barcelona, Barcelona, Spain
| | - José F. Rodríguez
- Centro Nacional de Biotecnología, CSIC, Madrid, Spain
- * E-mail: (JFR); (NV)
| | - Núria Verdaguer
- Institut de Biologia Molecular de Barcelona, CSIC, Parc Científic de Barcelona, Barcelona, Spain
- * E-mail: (JFR); (NV)
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Lauksund S, Greiner-Tollersrud L, Chang CJ, Robertsen B. Infectious pancreatic necrosis virus proteins VP2, VP3, VP4 and VP5 antagonize IFNa1 promoter activation while VP1 induces IFNa1. Virus Res 2014; 196:113-21. [PMID: 25445351 PMCID: PMC7114410 DOI: 10.1016/j.virusres.2014.11.018] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2014] [Revised: 11/11/2014] [Accepted: 11/13/2014] [Indexed: 12/25/2022]
Abstract
IPNV genes preVP2, VP3, VP4 and VP5 inhibited activation of the IFNa1 promoter. The viral protease VP4 was the most potent inhibitor of IFN induction. IFN antagonism by VP4 is independent of its protease activity. The RNA polymerase VP1 activated the IFNa1 promoter.
Infectious pancreatic necrosis virus (IPNV) is one of the major viral pathogens causing disease in farmed Atlantic salmon worldwide. In the present work we show that several of the IPN proteins have powerful antagonistic properties against type I IFN induction in Atlantic salmon. Each of the five IPNV genes cloned into an expression vector were tested for the ability to influence activation of the Atlantic salmon IFNa1 promoter by the interferon promoter inducing protein one (IPS-1) or interferon regulatory factors (IRF). This showed that preVP2, VP3 and VP5 inhibited activation of both promoters, while VP4 only antagonized activation of the IFNa1 promoter. The viral protease VP4 was the most potent inhibitor of IFN induction, apparently targeting the IRF1 and IRF3 branch of the signaling cascade. VP4 antagonism is independent of its protease activity since the catalytically dead mutant VP4K674A inhibited activation of the IFNa1 promoter to a similar extent as wild type VP4. In contrast to the other IPNV proteins, the RNA-dependent RNA polymerase VP1 activated the IFNa1 promoter. The ability to activate the IFN response was disrupted in the mutant VP1S163A, which has lost the ability to produce dsRNA. VP1 also exhibited synergistic effects with IRF1 and IRF3 in inducing an IFNa1-dependent antiviral state in cells. Taken together these results suggest that IPNV has developed multiple IFN antagonistic properties to prevent IFN-induction by VP1 and its dsRNA genome.
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Affiliation(s)
- Silje Lauksund
- Norwegian College of Fishery Science, University of Tromsø, 9037 Tromsø, Norway
| | | | - Chia-Jung Chang
- Norwegian College of Fishery Science, University of Tromsø, 9037 Tromsø, Norway
| | - Børre Robertsen
- Norwegian College of Fishery Science, University of Tromsø, 9037 Tromsø, Norway.
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An influenza A virus hemagglutinin (HA) epitope inserted in and expressed from several loci of the infectious bursal disease virus genome induces HA-specific antibodies. Arch Virol 2014; 159:2033-41. [DOI: 10.1007/s00705-014-2036-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2013] [Accepted: 02/25/2014] [Indexed: 10/25/2022]
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9
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cDNA cloning of Korean human norovirus and nucleotidylylation of VPg by norovirus RNA-dependent RNA polymerase. J Microbiol 2012; 50:625-30. [PMID: 22923111 DOI: 10.1007/s12275-012-2087-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2012] [Accepted: 05/29/2012] [Indexed: 10/28/2022]
Abstract
Norovirus, a member of the Caliciviridae family, is a major causative agent of gastroenteritis worldwide. The cDNA of the entire genome of human norovirus (HuNV) was cloned using the RNA extracted from the stool sample of a Korean patient. The RNA genome consists of 7,559 nucleotides, carries 3 open reading frames (ORFs), 5 and 3 noncoding regions, and a poly(A) tail at the 3 end. Phylogenic analysis of the nucleotide sequence indicated that it belongs to GII.4, the most dominant genogroup. To analyze RNA synthesis and nucleotidylylation of VPg by RNA-dependent RNA polymerase (RdRp), recombinant RdRp and VPg were expressed in Escherichia coli as His-tagged forms. The HuNV RdRp exhibited template and divalent cation-dependent RNA synthesis in vitro. The HuNV RdRp nucleotidylylated HuNV VPg but not murine norovirus (MNV) VPg, whereas MNV RdRp nucleotidylylated both MNV and HuNV VPg more efficiently than HuNV RdRp.
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Rivas-Aravena A, Martin MCS, Galaz J, Imarai M, Miranda D, Spencer E, Sandino A. Evaluation of the immune response against immature viral particles of infectious pancreatic necrosis virus (IPNV): A new model to develop an attenuated vaccine. Vaccine 2012; 30:5110-7. [DOI: 10.1016/j.vaccine.2012.05.062] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2011] [Revised: 05/09/2012] [Accepted: 05/25/2012] [Indexed: 01/13/2023]
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11
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Le Nouën C, Toquin D, Müller H, Raue R, Kean KM, Langlois P, Cherbonnel M, Eterradossi N. Different domains of the RNA polymerase of infectious bursal disease virus contribute to virulence. PLoS One 2012; 7:e28064. [PMID: 22253687 PMCID: PMC3258228 DOI: 10.1371/journal.pone.0028064] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2011] [Accepted: 10/31/2011] [Indexed: 01/13/2023] Open
Abstract
BACKGROUND Infectious bursal disease virus (IBDV) is a pathogen of worldwide significance to the poultry industry. IBDV has a bi-segmented double-stranded RNA genome. Segments A and B encode the capsid, ribonucleoprotein and non-structural proteins, or the virus polymerase (RdRp), respectively. Since the late eighties, very virulent (vv) IBDV strains have emerged in Europe inducing up to 60% mortality. Although some progress has been made in understanding the molecular biology of IBDV, the molecular basis for the pathogenicity of vvIBDV is still not fully understood. METHODOLOGY, PRINCIPAL FINDINGS Strain 88180 belongs to a lineage of pathogenic IBDV phylogenetically related to vvIBDV. By reverse genetics, we rescued a molecular clone (mc88180), as pathogenic as its parent strain. To study the molecular basis for 88180 pathogenicity, we constructed and characterized in vivo reassortant or mosaic recombinant viruses derived from the 88180 and the attenuated Cu-1 IBDV strains. The reassortant virus rescued from segments A of 88180 (A88) and B of Cu-1 (BCU1) was milder than mc88180 showing that segment B is involved in 88180 pathogenicity. Next, the exchange of different regions of BCU1 with their counterparts in B88 in association with A88 did not fully restore a virulence equivalent to mc88180. This demonstrated that several regions if not the whole B88 are essential for the in vivo pathogenicity of 88180. CONCLUSION, SIGNIFICANCE The present results show that different domains of the RdRp, are essential for the in vivo pathogenicity of IBDV, independently of the replication efficiency of the mosaic viruses.
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Affiliation(s)
- Cyril Le Nouën
- Avian and Rabbit Virology, Immunology and Parasitology Unit, OIE Reference Laboratory for Infectious Bursal Disease, French Agency for Food, Environmental and Occupational Health Safety (Anses), Ploufragan, France
| | - Didier Toquin
- Avian and Rabbit Virology, Immunology and Parasitology Unit, OIE Reference Laboratory for Infectious Bursal Disease, French Agency for Food, Environmental and Occupational Health Safety (Anses), Ploufragan, France
| | - Hermann Müller
- Institute for Virology, Faculty of Veterinary Medicine, University of Leipzig, Leipzig, Germany
| | - Rüdiger Raue
- Institute for Virology, Faculty of Veterinary Medicine, University of Leipzig, Leipzig, Germany
| | | | - Patrick Langlois
- Virus Genetics and Biosecurity Unit, French Agency for Food, Environmental and Occupational Health Safety (ANSES), Ploufragan, France
| | - Martine Cherbonnel
- Avian and Rabbit Virology, Immunology and Parasitology Unit, OIE Reference Laboratory for Infectious Bursal Disease, French Agency for Food, Environmental and Occupational Health Safety (Anses), Ploufragan, France
| | - Nicolas Eterradossi
- Avian and Rabbit Virology, Immunology and Parasitology Unit, OIE Reference Laboratory for Infectious Bursal Disease, French Agency for Food, Environmental and Occupational Health Safety (Anses), Ploufragan, France
- * E-mail:
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12
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Graham SC, Sarin LP, Bahar MW, Myers RA, Stuart DI, Bamford DH, Grimes JM. The N-terminus of the RNA polymerase from infectious pancreatic necrosis virus is the determinant of genome attachment. PLoS Pathog 2011; 7:e1002085. [PMID: 21731487 PMCID: PMC3121795 DOI: 10.1371/journal.ppat.1002085] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2010] [Accepted: 04/11/2011] [Indexed: 12/30/2022] Open
Abstract
The RNA-dependent RNA polymerase VP1 of infectious pancreatic necrosis virus (IPNV) is a single polypeptide responsible for both viral RNA transcription and genome replication. Sequence analysis identifies IPNV VP1 as having an unusual active site topology. We have purified, crystallized and solved the structure of IPNV VP1 to 2.3 Å resolution in its apo form and at 2.2 Å resolution bound to the catalytically-activating metal magnesium. We find that recombinantly-expressed VP1 is highly active for RNA transcription and replication, yielding both free and polymerase-attached RNA products. IPNV VP1 also possesses terminal (deoxy)nucleotide transferase, RNA-dependent DNA polymerase (reverse transcriptase) and template-independent self-guanylylation activity. The N-terminus of VP1 interacts with the active-site cleft and we show that the N-terminal serine residue is required for formation of covalent RNA∶polymerase complexes, providing a mechanism for the genesis of viral genome∶polymerase complexes observed in vivo. Infectious pancreatic necrosis virus (IPNV) is highly contagious and causes severe disease in fish. As a result of intensive rearing conditions it has become a serious problem for the salmon and trout farming industries. IPNV, like many other viruses, replicates its genome using a protein (a ‘polymerase’) that is itself encoded by the viral genome. Unusually, in infectious IPNV particles the polymerase is found chemically linked to the viral genome. We have determined the atomic structure of IPNV polymerase using X-ray crystallography, revealing some significant differences in the fold of the protein chain compared to other well-characterized viral polymerases. By mutating an amino acid residue at the beginning of the protein we show how the chemical linkage to the viral genome can be disrupted. This provides an elegant mechanism for the attachment of the viral genome to the polymerase observed in vivo.
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Affiliation(s)
- Stephen C. Graham
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - L. Peter Sarin
- Institute of Biotechnology and Department of Biosciences, University of Helsinki, Biocenter 2, Helsinki, Finland
| | - Mohammad W. Bahar
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Reg A. Myers
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - David I. Stuart
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Dennis H. Bamford
- Institute of Biotechnology and Department of Biosciences, University of Helsinki, Biocenter 2, Helsinki, Finland
- * E-mail: (DHB); (JMG)
| | - Jonathan M. Grimes
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
- * E-mail: (DHB); (JMG)
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13
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Jofré C, Guzmán F, Cárdenas C, Albericio F, Marshall SH. A natural peptide and its variants derived from the processing of infectious pancreatic necrosis virus (IPNV) displaying enhanced antimicrobial activity: a novel alternative for the control of bacterial diseases. Peptides 2011; 32:852-8. [PMID: 21291934 DOI: 10.1016/j.peptides.2011.01.026] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2010] [Revised: 01/20/2011] [Accepted: 01/20/2011] [Indexed: 11/24/2022]
Abstract
The larger segment of the infectious pancreatic necrosis virus (IPNV) codifies most of the structural and non-structural proteins of the virus in two overlapping open reading frames (ORFs). The longer of the two ORF is expressed as a polyprotein which generates a number of variable length peptides of unknown function during processing. Since an appealing hypothesis would be that these peptides are generated by the virus to act as antimicrobial agents that favor viral infectivity in their fish host, we decided to test this possibility by selecting a master peptide and using it to generate substitution variants that may enhance their antimicrobial potential. A 20-residue master peptide (p20) was selected from the well-described maturation process of the structural viral protein VP2; several variants were then designed and chemically synthesized, ranging in size from 16 to 20 residues. The synthesized peptides were tested for in vitro activity against several prototype bacterial pathogens using standardized laboratory procedures. Chemically synthesized p20 and all its variants displayed broad activity against the tested bacteria and none of them were toxic to eukaryotic cells at least 10× the concentration used against the bacteria. Interestingly, when p20 was tested against the very aggressive bacterial pathogen Piscirickettsia salmonis, a common co-infectant of IPNV in salmonid fish, the specific activity of the novel peptide was significantly higher than that displayed for bactericidal fish farm antibiotics such as oxolinic acid, flumequine and florfenicol, which are commonly used to control Piscirickettsiosis in the field. It is potentially significant that the approach presented in this report provides a novel alternative for generating new and ideally more efficient and friendly safeguards for bacterial prophylaxis.
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Affiliation(s)
- Claudio Jofré
- Laboratorio de Genética e Inmunología Molecular, Instituto de Biología, Facultad de Ciencias, Pontificia Universidad Católica de Valparaíso, Campus Curauma, Av Parque Sur, Valparaíso, Chile.
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14
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Euprosterna elaeasa virus genome sequence and evolution of the Tetraviridae family: emergence of bipartite genomes and conservation of the VPg signal with the dsRNA Birnaviridae family. Virology 2009; 397:145-54. [PMID: 19954807 DOI: 10.1016/j.virol.2009.10.042] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2009] [Revised: 10/08/2009] [Accepted: 10/28/2009] [Indexed: 11/21/2022]
Abstract
The Tetraviridae is a family of non-enveloped positive-stranded RNA insect viruses that is defined by the T=4 symmetry of virions. We report the complete Euprosterna elaeasa virus (EeV) genome sequence of 5698 nt with no poly(A) tail and two overlapping open reading frames, encoding the replicase and capsid precursor, with approximately 67% amino acid identity to Thosea asigna virus (TaV). The N-terminally positioned 17 kDa protein is released from the capsid precursor by a NPGP motif. EeV has 40 nm non-enveloped isometric particles composed of 58 and 7 kDa proteins. The 3'-end of TaV/EeV is predicted to form a conserved pseudoknot. Replicases of TaV and EeV include a newly delineated VPg signal mediating the protein priming of RNA synthesis in dsRNA Birnaviridae. Results of rooted phylogenetic analysis of replicase and capsid proteins are presented to implicate recombination between monopartite tetraviruses, involving autonomization of a sgRNA, in the emergence of bipartite tetraviruses. They are also used to revise the Tetraviridae taxonomy.
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15
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Pan J, Lin L, Tao YJ. Self-guanylylation of birnavirus VP1 does not require an intact polymerase activity site. Virology 2009; 395:87-96. [PMID: 19801157 DOI: 10.1016/j.virol.2009.09.004] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2009] [Revised: 08/19/2009] [Accepted: 09/04/2009] [Indexed: 11/27/2022]
Abstract
Protein priming is an important mechanism that many viruses use to initiate genomic DNA or RNA synthesis. Birnaviruses are the only double-stranded (ds) RNA viruses that use protein priming. The viral-encoded VP1 of birnavirus functions as both a polymerase and a protein primer and is able to undergo self-guanylylation to acquire a covalently linked rGMP. By employing biochemical assays using recombinant proteins, we have shown that VP1 self-guanylylation does not require an RNA template but is dependent on divalent metal ions. VP1 reacts with all four types of rNTPs but strongly prefers rGTP. Unexpectedly, two fatal polymerase mutants D402A and E421Y, each having an essential catalytic residue mutated and unable to catalyze RNA synthesis, remain active in self-guanylylation. The guanylylation site was further mapped to the VP1 N-terminal domain. Our results support a mechanism in which VP1 self-guanylylation is catalyzed by a novel active site different from the polymerase active site.
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Affiliation(s)
- Junhua Pan
- Department of Biochemistry and Cell Biology, Rice University, 6100 Main Street, Houston, TX 77005, USA
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16
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Sabanadzovic S, Ghanem-Sabanadzovic NA, Gorbalenya AE. Permutation of the active site of putative RNA-dependent RNA polymerase in a newly identified species of plant alpha-like virus. Virology 2009; 394:1-7. [PMID: 19793602 DOI: 10.1016/j.virol.2009.08.006] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2009] [Revised: 06/05/2009] [Accepted: 08/04/2009] [Indexed: 11/30/2022]
Abstract
To direct the genome synthesis, RNA viruses without a DNA stage in the replication cycle use RNA-dependent RNA polymerase (RdRp). All RdRps have conserved right hand-like shape that includes characteristic A-->B-->C sequence motifs forming the active site. Recently, the structural permutation of the RdRp active site (C-->A-->B) has been described in few double-stranded RNA birnaviruses and a subset of positive-stranded RNA tetraviruses distantly related to Picorna-like viruses. Here we describe a permuted RdRp in the newly identified plant alpha-like virus with 6.5 kb-long polyadenylated genome, dubbed Grapevine virus Q (GVQ). The multi-domain layout and sequence similarities place GVQ into the genus Marafivirus of the family Tymoviridae. In contrast to other tymovirids, GVQ has 21 amino acid residues corresponding to the motif C relocated upstream of the motif A in the putative RdRp. This unique sequence characteristic was extensively verified and identified in several GVQ isolates infecting wild and cultivated Vitis and Rubus spp.
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Affiliation(s)
- Sead Sabanadzovic
- Department of Entomology, Mississippi State University, Mississippi State, MS 39762, USA.
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17
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Irigoyen N, Garriga D, Navarro A, Verdaguer N, Rodríguez JF, Castón JR. Autoproteolytic activity derived from the infectious bursal disease virus capsid protein. J Biol Chem 2009; 284:8064-72. [PMID: 19144647 PMCID: PMC2658100 DOI: 10.1074/jbc.m808942200] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2008] [Revised: 12/19/2008] [Indexed: 11/06/2022] Open
Abstract
Viral capsids are envisioned as vehicles to deliver the viral genome to the host cell. They are nonetheless dynamic protective shells, as they participate in numerous processes of the virus cycle such as assembly, genome packaging, binding to receptors, and uncoating among others. In so doing, they undergo large scale conformational changes. Capsid proteins with essential enzymatic activities are being described more frequently. Here we show that the precursor (pVP2) of the capsid protein VP2 of the infectious bursal disease virus (IBDV), an avian double-stranded RNA virus, has autoproteolytic activity. The pVP2 C-terminal region is first processed by the viral protease VP4. VP2 Asp-431, lying in a flexible loop preceding the C-terminal most alpha-helix, is responsible for the endopeptidase activity that cleaves the Ala-441-Phe-442 bond to generate the mature VP2 polypeptide. The D431N substitution abrogates the endopeptidase activity without introducing a significant conformational change, as deduced from the three-dimensional structure of the mutant protein at 3.1 A resolution. Combinations of VP2 polypeptides containing mutations affecting either the cleavage or the catalytic site revealed that pVP2 proteolytic processing is the result of a monomolecular cis-cleavage reaction. The D431N mutation does not affect the assembly of the VP2 trimers that constitute the capsid building block. Although VP2 D431N trimers are capable of assembling both pentamers and hexamers, expression of a polyprotein gene harboring the D431N mutation does not result in the assembly of IBDV virus-like particles. Reverse genetics analyses demonstrate that pVP2 self-processing is essential for the assembly of an infectious IBDV progeny.
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Affiliation(s)
- Nerea Irigoyen
- Department of Molecular and Cellular Biology, Centro Nacional de Biotecnología/Consejo Superior de Investigaciones Científicas (CSIC), Cantoblanco, 28049 Madrid, Spain
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18
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Hon CC, Lam TTY, Yip CW, Wong RTY, Shi M, Jiang J, Zeng F, Leung FCC. Phylogenetic evidence for homologous recombination within the family Birnaviridae. J Gen Virol 2009; 89:3156-3164. [PMID: 19008406 DOI: 10.1099/vir.0.2008/004101-0] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Birnaviruses are bi-segmented double-stranded RNA (dsRNA) viruses infecting insects, avian species and a wide range of aquatic species. Although homologous recombination is a common phenomenon in positive-sense RNA viruses, recombination in dsRNA viruses is rarely reported. Here we performed a comprehensive survey on homologous recombination in all available sequences (>1800) of the family Birnaviridae based on phylogenetic incongruence. Although inter-species recombination was not evident, potential intra-species recombination events were detected in aquabirnaviruses and infectious bursal disease virus (IBDV). Eight potential recombination events were identified and the possibility that these events were non-naturally occurring was assessed case by case. Five of the eight events were identified in IBDVs and all of these five events involved live attenuated vaccine strains. This finding suggests that homologous recombination between vaccine and wild-type IBDV strains may have occurred; the potential risk of mass vaccination using live vaccines is discussed. This is the first report of evidence for homologous recombination within the family Birnaviridae.
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Affiliation(s)
- Chung-Chau Hon
- School of Biological Sciences, The University of Hong Kong, Hong Kong SAR
| | - Tommy Tsan-Yuk Lam
- School of Biological Sciences, The University of Hong Kong, Hong Kong SAR
| | - Chi-Wai Yip
- School of Biological Sciences, The University of Hong Kong, Hong Kong SAR
| | | | - Mang Shi
- School of Biological Sciences, The University of Hong Kong, Hong Kong SAR
| | - Jingwei Jiang
- School of Biological Sciences, The University of Hong Kong, Hong Kong SAR
| | - Fanya Zeng
- School of Biological Sciences, The University of Hong Kong, Hong Kong SAR
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19
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Activation mechanism of a noncanonical RNA-dependent RNA polymerase. Proc Natl Acad Sci U S A 2007; 104:20540-5. [PMID: 18077388 DOI: 10.1073/pnas.0704447104] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Two lineages of viral RNA-dependent RNA polymerases (RDRPs) differing in the organization (canonical vs. noncanonical) of the palm subdomain have been identified. Phylogenetic analyses indicate that both lineages diverged at a very early stage of the evolution of the enzyme [Gorbalenya AE, Pringle FM, Zeddam JL, Luke BT, Cameron CE, Kalmakoff J, Hanzlik TN, Gordon KH, Ward VK (2002) J Mol Biol 324:47-62]. Here, we report the x-ray structure of a noncanonical birnaviral RDRP, named VP1, in its free form, bound to Mg(2+) ions, and bound to a peptide representing the polymerase-binding motif of the regulatory viral protein VP3. The structure of VP1 reveals that the noncanonical connectivity of the palm subdomain maintains the geometry of the catalytic residues found in canonical polymerases but results in a partial blocking of the active site cavity. The VP1-VP3 peptide complex shows a mode of polymerase activation in which VP3 binding promotes a conformational change that removes the steric blockade of the VP1 active site, facilitating the accommodation of the template and incoming nucleotides for catalysis. The striking structural similarities between birnavirus (dsRNA) and the positive-stranded RNA picornavirus and calicivirus RDRPs provide evidence supporting the existence of functional and evolutionary relationships between these two virus groups.
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20
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Letzel T, Mundt E, Gorbalenya AE. Evidence for functional significance of the permuted C motif in Co2+-stimulated RNA-dependent RNA polymerase of infectious bursal disease virus. J Gen Virol 2007; 88:2824-2833. [PMID: 17872536 DOI: 10.1099/vir.0.82890-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Segment B of bisegmented infectious bursal disease virus (IBDV) encodes virus protein 1 (VP1), possessing RNA-dependent RNA polymerase (RdRp) activity. This multidomain protein includes an RdRp domain with a non-canonical order of three sequence motifs forming the active site: C-A-B. The A-B-C order of the motifs, as found in RdRps of the majority of viruses, was converted by relocation (permutation) of motif C to a C-A-B order. Due to the unusual location and unproven significance, the motif was named 'C?'. This motif includes an Ala-Asp-Asn tripeptide that replaces the C motif Gly-Asp-Asp sequence, widely considered a hallmark of RdRps. In this study, functional significance of the C? motif was investigated by using purified His-tagged VP1 mutants with either a double replacement (ADN to GDD) or two single-site mutants (ADD or GDN). All mutants showed a significant reduction of RdRp activity in vitro, in comparison to that of VP1. Only the least-affected GDN mutant gave rise to viable, albeit partially impaired, progeny using a reverse-genetics system. Experiments performed to investigate whether the C motif was implicated in the control of metal dependence revealed that, compared with Mn2+ and Mg2+, Co2+ stimulated RdRp unconventionally. No activity was observed in the presence of several divalent cations. Of two Co2+ salts with Cl- and SO4(2-) anions, the former was a stronger stimulant for RdRp. When cell-culture medium was supplemented with 50 microM Co2+, an increase in IBDV progeny yield was observed. The obtained results provide evidence that the unusual Co2+ dependence of the IBDV RdRp might be linked to the permuted organization of the motif.
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Affiliation(s)
- Tobias Letzel
- Institutes of Molecular Biology, Friedrich-Loeffler-Institut, 17493 Greifswald-Insel Riems, Germany
| | - Egbert Mundt
- Institutes of Molecular Biology, Friedrich-Loeffler-Institut, 17493 Greifswald-Insel Riems, Germany
| | - Alexander E Gorbalenya
- Molecular Virology Laboratory, Department of Medical Microbiology, Leiden University Medical Center, PO Box 9600, 2300RC Leiden, The Netherlands
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Pan J, Vakharia VN, Tao YJ. The structure of a birnavirus polymerase reveals a distinct active site topology. Proc Natl Acad Sci U S A 2007; 104:7385-90. [PMID: 17456597 PMCID: PMC1855279 DOI: 10.1073/pnas.0611599104] [Citation(s) in RCA: 99] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Single-subunit polymerases are universally encoded in both cellular organisms and viruses. Their three-dimensional structures have the shape of a right-hand with the active site located in the palm region, which has a topology similar to that of the RNA recognition motif (RRM) found in many RNA-binding proteins. Considering that polymerases have well conserved structures, it was surprising that the RNA-dependent RNA polymerases from birnaviruses, a group of dsRNA viruses, have their catalytic motifs arranged in a permuted order in sequence. Here we report the 2.5 A structure of a birnavirus VP1 in which the polymerase palm subdomain adopts a new active site topology that has not been previously observed in other polymerases. In addition, the polymerase motif C of VP1 has the sequence of -ADN-, a highly unusual feature for RNA-dependent polymerases. Through site-directed mutagenesis, we have shown that changing the VP1 motif C from -ADN- to -GDD- results in a mutant with an increased RNA synthesis activity. Our results indicate that the active site topology of VP1 may represent a newly developed branch in polymerase evolution, and that birnaviruses may have acquired the -ADN- mutation to control their growth rate.
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Affiliation(s)
- Junhua Pan
- *Department of Biochemistry and Cell Biology, Rice University, Houston, TX 77005; and
| | - Vikram N. Vakharia
- Center for Biosystems Research, University of Maryland Biotechnology Institute, College Park, MD 20742
| | - Yizhi Jane Tao
- *Department of Biochemistry and Cell Biology, Rice University, Houston, TX 77005; and
- To whom correspondence should be addressed. E-mail:
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Pedersen T, Skjesol A, Jørgensen JB. VP3, a structural protein of infectious pancreatic necrosis virus, interacts with RNA-dependent RNA polymerase VP1 and with double-stranded RNA. J Virol 2007; 81:6652-63. [PMID: 17428850 PMCID: PMC1900092 DOI: 10.1128/jvi.02831-06] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Infectious pancreatic necrosis virus (IPNV) is a bisegmented, double-stranded RNA (dsRNA) virus of the Birnaviridae family that causes widespread disease in salmonids. Its two genomic segments are encapsulated together with the viral RNA-dependent RNA polymerase, VP1, and the assumed internal protein, VP3, in a single-shell capsid composed of VP2. Major aspects of the molecular biology of IPNV, such as particle assembly and interference with host macromolecules, are as yet poorly understood. To understand the infection process, analysis of viral protein interactions is of crucial importance. In this study, we focus on the interaction properties of VP3, the suggested key organizer of particle assembly in birnaviruses. By applying the yeast two-hybrid system in combination with coimmunoprecipitation, VP3 was proven to bind to VP1 and to self-associate strongly. In addition, VP3 was shown to specifically bind to dsRNA in a sequence-independent manner by in vitro pull-down experiments. The binding between VP3 and VP1 was not dependent on the presence of dsRNA. Deletion analyses mapped the VP3 self-interaction domain within the 101 N-terminal amino acids and the VP1 interaction domain within the 62 C-terminal amino acids of VP3. The C-terminal end was also crucial but not sufficient for the dsRNA binding capacity of VP3. For VP1, the 90 C-terminal amino acids constituted the only dispensable part for maintaining VP3-binding ability. Kinetic analysis revealed the presence of VP1-VP3 complexes prior to the formation of mature virions in IPNV-infected CHSE-214 cells, which indicates a role in promoting the assembly process.
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Affiliation(s)
- Torunn Pedersen
- Department of Marine Biotechnology, Norwegian College of Fishery Sciences, University of Tromsø, N-9037 Tromsø, Norway
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