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Hinojosa Y, Liniger M, García-Nicolás O, Gerber M, Rajaratnam A, Muñoz-González S, Coronado L, Frías MT, Perera CL, Ganges L, Ruggli N. Evolutionary-Related High- and Low-Virulent Classical Swine Fever Virus Isolates Reveal Viral Determinants of Virulence. Viruses 2024; 16:147. [PMID: 38275957 PMCID: PMC10820463 DOI: 10.3390/v16010147] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2023] [Revised: 01/13/2024] [Accepted: 01/15/2024] [Indexed: 01/27/2024] Open
Abstract
Classical swine fever (CSF) has been eradicated from Western and Central Europe but remains endemic in parts of Central and South America, Asia, and the Caribbean. CSF virus (CSFV) has been endemic in Cuba since 1993, most likely following an escape of the highly virulent Margarita/1958 strain. In recent years, chronic and persistent infections with low-virulent CSFV have been observed. Amino acid substitutions located in immunodominant epitopes of the envelope glycoprotein E2 of the attenuated isolates were attributed to positive selection due to suboptimal vaccination and control. To obtain a complete picture of the mutations involved in attenuation, we applied forward and reverse genetics using the evolutionary-related low-virulent CSFV/Pinar del Rio (CSF1058)/2010 (PdR) and highly virulent Margarita/1958 isolates. Sequence comparison of the two viruses recovered from experimental infections in pigs revealed 40 amino acid differences. Interestingly, the amino acid substitutions clustered in E2 and the NS5A and NS5B proteins. A long poly-uridine sequence was identified previously in the 3' untranslated region (UTR) of PdR. We constructed functional cDNA clones of the PdR and Margarita strains and generated eight recombinant viruses by introducing single or multiple gene fragments from Margarita into the PdR backbone. All chimeric viruses had comparable replication characteristics in porcine monocyte-derived macrophages. Recombinant PdR viruses carrying either E2 or NS5A/NS5B of Margarita, with 36 or 5 uridines in the 3'UTR, remained low virulent in 3-month-old pigs. The combination of these elements recovered the high-virulent Margarita phenotype. These results show that CSFV evolution towards attenuated variants in the field involved mutations in both structural and non-structural proteins and the UTRs, which act synergistically to determine virulence.
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Affiliation(s)
- Yoandry Hinojosa
- Division of Virology, Institute of Virology and Immunology IVI, 3147 Mittelhäusern, Switzerland; (Y.H.); (M.L.); (O.G.-N.); (M.G.)
- Department of Infectious Diseases and Pathobiology (DIP), University of Bern, 3012 Bern, Switzerland
- Graduate School for Cellular and Biomedical Sciences (GCB), University of Bern, 3012 Bern, Switzerland
- Centro Nacional de Sanidad Agropecuaria (CENSA), San José de las Lajas 32700, Cuba; (M.T.F.); (C.L.P.)
| | - Matthias Liniger
- Division of Virology, Institute of Virology and Immunology IVI, 3147 Mittelhäusern, Switzerland; (Y.H.); (M.L.); (O.G.-N.); (M.G.)
- Department of Infectious Diseases and Pathobiology (DIP), University of Bern, 3012 Bern, Switzerland
| | - Obdulio García-Nicolás
- Division of Virology, Institute of Virology and Immunology IVI, 3147 Mittelhäusern, Switzerland; (Y.H.); (M.L.); (O.G.-N.); (M.G.)
- Department of Infectious Diseases and Pathobiology (DIP), University of Bern, 3012 Bern, Switzerland
| | - Markus Gerber
- Division of Virology, Institute of Virology and Immunology IVI, 3147 Mittelhäusern, Switzerland; (Y.H.); (M.L.); (O.G.-N.); (M.G.)
- Department of Infectious Diseases and Pathobiology (DIP), University of Bern, 3012 Bern, Switzerland
| | - Anojen Rajaratnam
- Division of Virology, Institute of Virology and Immunology IVI, 3147 Mittelhäusern, Switzerland; (Y.H.); (M.L.); (O.G.-N.); (M.G.)
- Department of Infectious Diseases and Pathobiology (DIP), University of Bern, 3012 Bern, Switzerland
| | - Sara Muñoz-González
- WOAH Reference Laboratory for Classical Swine Fever, IRTA-CReSA, 08193 Barcelona, Spain; (S.M.-G.); (L.C.); (L.G.)
- Unitat Mixta d’Investigació IRTA-UAB en Sanitat Animal, Centre de Recerca en Sanitat Animal (CReSA), 08193 Barcelona, Spain
| | - Liani Coronado
- WOAH Reference Laboratory for Classical Swine Fever, IRTA-CReSA, 08193 Barcelona, Spain; (S.M.-G.); (L.C.); (L.G.)
- Unitat Mixta d’Investigació IRTA-UAB en Sanitat Animal, Centre de Recerca en Sanitat Animal (CReSA), 08193 Barcelona, Spain
- IRTA, Programa de Sanitat Animal, Centre de Recerca en Sanitat Animal (CReSA), 08193 Barcelona, Spain
| | - María Teresa Frías
- Centro Nacional de Sanidad Agropecuaria (CENSA), San José de las Lajas 32700, Cuba; (M.T.F.); (C.L.P.)
| | - Carmen Laura Perera
- Centro Nacional de Sanidad Agropecuaria (CENSA), San José de las Lajas 32700, Cuba; (M.T.F.); (C.L.P.)
| | - Llilianne Ganges
- WOAH Reference Laboratory for Classical Swine Fever, IRTA-CReSA, 08193 Barcelona, Spain; (S.M.-G.); (L.C.); (L.G.)
- Unitat Mixta d’Investigació IRTA-UAB en Sanitat Animal, Centre de Recerca en Sanitat Animal (CReSA), 08193 Barcelona, Spain
- IRTA, Programa de Sanitat Animal, Centre de Recerca en Sanitat Animal (CReSA), 08193 Barcelona, Spain
| | - Nicolas Ruggli
- Division of Virology, Institute of Virology and Immunology IVI, 3147 Mittelhäusern, Switzerland; (Y.H.); (M.L.); (O.G.-N.); (M.G.)
- Department of Infectious Diseases and Pathobiology (DIP), University of Bern, 3012 Bern, Switzerland
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2
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Sherwood AV, Rivera-Rangel LR, Ryberg LA, Larsen HS, Anker KM, Costa R, Vågbø CB, Jakljevič E, Pham LV, Fernandez-Antunez C, Indrisiunaite G, Podolska-Charlery A, Grothen JER, Langvad NW, Fossat N, Offersgaard A, Al-Chaer A, Nielsen L, Kuśnierczyk A, Sølund C, Weis N, Gottwein JM, Holmbeck K, Bottaro S, Ramirez S, Bukh J, Scheel TKH, Vinther J. Hepatitis C virus RNA is 5'-capped with flavin adenine dinucleotide. Nature 2023:10.1038/s41586-023-06301-3. [PMID: 37407817 DOI: 10.1038/s41586-023-06301-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Accepted: 06/08/2023] [Indexed: 07/07/2023]
Abstract
RNA viruses have evolved elaborate strategies to protect their genomes, including 5' capping. However, until now no RNA 5' cap has been identified for hepatitis C virus1,2 (HCV), which causes chronic infection, liver cirrhosis and cancer3. Here we demonstrate that the cellular metabolite flavin adenine dinucleotide (FAD) is used as a non-canonical initiating nucleotide by the viral RNA-dependent RNA polymerase, resulting in a 5'-FAD cap on the HCV RNA. The HCV FAD-capping frequency is around 75%, which is the highest observed for any RNA metabolite cap across all kingdoms of life4-8. FAD capping is conserved among HCV isolates for the replication-intermediate negative strand and partially for the positive strand. It is also observed in vivo on HCV RNA isolated from patient samples and from the liver and serum of a human liver chimeric mouse model. Furthermore, we show that 5'-FAD capping protects RNA from RIG-I mediated innate immune recognition but does not stabilize the HCV RNA. These results establish capping with cellular metabolites as a novel viral RNA-capping strategy, which could be used by other viruses and affect anti-viral treatment outcomes and persistence of infection.
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Affiliation(s)
- Anna V Sherwood
- Section for Computational and RNA Biology, Department of Biology, University of Copenhagen, Copenhagen N, Denmark
| | - Lizandro R Rivera-Rangel
- Copenhagen Hepatitis C Program (CO-HEP), Department of Infectious Diseases, Copenhagen University Hospital, Hvidovre, Denmark
- Copenhagen Hepatitis C Program (CO-HEP), Department of Immunology and Microbiology, University of Copenhagen, Copenhagen N, Denmark
| | - Line A Ryberg
- Copenhagen Hepatitis C Program (CO-HEP), Department of Infectious Diseases, Copenhagen University Hospital, Hvidovre, Denmark
- Copenhagen Hepatitis C Program (CO-HEP), Department of Immunology and Microbiology, University of Copenhagen, Copenhagen N, Denmark
| | - Helena S Larsen
- Copenhagen Hepatitis C Program (CO-HEP), Department of Infectious Diseases, Copenhagen University Hospital, Hvidovre, Denmark
- Copenhagen Hepatitis C Program (CO-HEP), Department of Immunology and Microbiology, University of Copenhagen, Copenhagen N, Denmark
| | - Klara M Anker
- Section for Computational and RNA Biology, Department of Biology, University of Copenhagen, Copenhagen N, Denmark
| | - Rui Costa
- Copenhagen Hepatitis C Program (CO-HEP), Department of Infectious Diseases, Copenhagen University Hospital, Hvidovre, Denmark
- Copenhagen Hepatitis C Program (CO-HEP), Department of Immunology and Microbiology, University of Copenhagen, Copenhagen N, Denmark
| | - Cathrine B Vågbø
- Proteomics and Modomics Experimental Core (PROMEC), Norwegian University of Science and Technology and the Central Norway Regional Health Authority, Trondheim, Norway
| | - Eva Jakljevič
- Copenhagen Hepatitis C Program (CO-HEP), Department of Infectious Diseases, Copenhagen University Hospital, Hvidovre, Denmark
- Copenhagen Hepatitis C Program (CO-HEP), Department of Immunology and Microbiology, University of Copenhagen, Copenhagen N, Denmark
| | - Long V Pham
- Copenhagen Hepatitis C Program (CO-HEP), Department of Infectious Diseases, Copenhagen University Hospital, Hvidovre, Denmark
- Copenhagen Hepatitis C Program (CO-HEP), Department of Immunology and Microbiology, University of Copenhagen, Copenhagen N, Denmark
| | - Carlota Fernandez-Antunez
- Copenhagen Hepatitis C Program (CO-HEP), Department of Infectious Diseases, Copenhagen University Hospital, Hvidovre, Denmark
- Copenhagen Hepatitis C Program (CO-HEP), Department of Immunology and Microbiology, University of Copenhagen, Copenhagen N, Denmark
| | - Gabriele Indrisiunaite
- Section for Computational and RNA Biology, Department of Biology, University of Copenhagen, Copenhagen N, Denmark
| | - Agnieszka Podolska-Charlery
- Section for Computational and RNA Biology, Department of Biology, University of Copenhagen, Copenhagen N, Denmark
| | - Julius E R Grothen
- Section for Computational and RNA Biology, Department of Biology, University of Copenhagen, Copenhagen N, Denmark
| | - Nicklas W Langvad
- Section for Computational and RNA Biology, Department of Biology, University of Copenhagen, Copenhagen N, Denmark
| | - Nicolas Fossat
- Copenhagen Hepatitis C Program (CO-HEP), Department of Infectious Diseases, Copenhagen University Hospital, Hvidovre, Denmark
- Copenhagen Hepatitis C Program (CO-HEP), Department of Immunology and Microbiology, University of Copenhagen, Copenhagen N, Denmark
| | - Anna Offersgaard
- Copenhagen Hepatitis C Program (CO-HEP), Department of Infectious Diseases, Copenhagen University Hospital, Hvidovre, Denmark
- Copenhagen Hepatitis C Program (CO-HEP), Department of Immunology and Microbiology, University of Copenhagen, Copenhagen N, Denmark
| | - Amal Al-Chaer
- Section for Computational and RNA Biology, Department of Biology, University of Copenhagen, Copenhagen N, Denmark
| | - Louise Nielsen
- Copenhagen Hepatitis C Program (CO-HEP), Department of Infectious Diseases, Copenhagen University Hospital, Hvidovre, Denmark
- Copenhagen Hepatitis C Program (CO-HEP), Department of Immunology and Microbiology, University of Copenhagen, Copenhagen N, Denmark
| | - Anna Kuśnierczyk
- Proteomics and Modomics Experimental Core (PROMEC), Norwegian University of Science and Technology and the Central Norway Regional Health Authority, Trondheim, Norway
| | - Christina Sølund
- Department of Infectious Diseases, Copenhagen University Hospital, Hvidovre, Denmark
- Department of Clinical Medicine, University of Copenhagen, Copenhagen N, Denmark
| | - Nina Weis
- Department of Infectious Diseases, Copenhagen University Hospital, Hvidovre, Denmark
- Department of Clinical Medicine, University of Copenhagen, Copenhagen N, Denmark
| | - Judith M Gottwein
- Copenhagen Hepatitis C Program (CO-HEP), Department of Infectious Diseases, Copenhagen University Hospital, Hvidovre, Denmark
- Copenhagen Hepatitis C Program (CO-HEP), Department of Immunology and Microbiology, University of Copenhagen, Copenhagen N, Denmark
| | - Kenn Holmbeck
- Copenhagen Hepatitis C Program (CO-HEP), Department of Infectious Diseases, Copenhagen University Hospital, Hvidovre, Denmark
- Copenhagen Hepatitis C Program (CO-HEP), Department of Immunology and Microbiology, University of Copenhagen, Copenhagen N, Denmark
| | - Sandro Bottaro
- Section for Biomolecular Sciences, Department of Biology, University of Copenhagen, Copenhagen N, Denmark
| | - Santseharay Ramirez
- Copenhagen Hepatitis C Program (CO-HEP), Department of Infectious Diseases, Copenhagen University Hospital, Hvidovre, Denmark
- Copenhagen Hepatitis C Program (CO-HEP), Department of Immunology and Microbiology, University of Copenhagen, Copenhagen N, Denmark
| | - Jens Bukh
- Copenhagen Hepatitis C Program (CO-HEP), Department of Infectious Diseases, Copenhagen University Hospital, Hvidovre, Denmark.
- Copenhagen Hepatitis C Program (CO-HEP), Department of Immunology and Microbiology, University of Copenhagen, Copenhagen N, Denmark.
| | - Troels K H Scheel
- Copenhagen Hepatitis C Program (CO-HEP), Department of Infectious Diseases, Copenhagen University Hospital, Hvidovre, Denmark.
- Copenhagen Hepatitis C Program (CO-HEP), Department of Immunology and Microbiology, University of Copenhagen, Copenhagen N, Denmark.
- Laboratory of Virology and Infectious Disease, The Rockefeller University, New York, NY, USA.
| | - Jeppe Vinther
- Section for Computational and RNA Biology, Department of Biology, University of Copenhagen, Copenhagen N, Denmark.
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3
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Glassman KF, Brugge JS, Purchio AF, Kakach LT, Fuerst TR, Woods RM, Stover CK, Chunduru SK, Hincks JR, McKinlay MA, Nash CH, Pevear DC, Monath TP, Rice CM, Peters P. Biographical Feature: Marc S. Collett (23 May 1951-11 June 2022): the Battle against Viral Disease Has Lost a Valiant Warrior, and the World Has Lost a Splendid Human Being. J Virol 2023; 97:e0164322. [PMID: 36468860 PMCID: PMC9888289 DOI: 10.1128/jvi.01643-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/09/2022] Open
Affiliation(s)
| | - Joan S. Brugge
- Ludwig Center, Harvard Medical School, Harvard University, Boston, Massachusetts, USA
| | | | | | - Thomas R. Fuerst
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland, USA
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Host Cell Receptors Implicated in the Cellular Tropism of BVDV. Viruses 2022; 14:v14102302. [PMID: 36298858 PMCID: PMC9607657 DOI: 10.3390/v14102302] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2022] [Revised: 10/13/2022] [Accepted: 10/17/2022] [Indexed: 12/02/2022] Open
Abstract
Bovine viral diarrhea virus (BVDV) is one of the most hazardous viruses, which causes huge economic losses in the cattle industry around the world. In recent years, there has been a continuous increase in the diversity of pestivirus worldwide. As a member of the genus Pestivirus in the Flaviviridae family, BVDV has a wide range of host animals including cattle, goat, sheep, pig, camel and other cloven-hoofed animals, and it has multi-tissue tropism as well. The recognition of their permissive cells by viruses via interaction with the cellular receptors is a prerequisite for successful infection. So far, little is known about the cellular receptors essential for BVDV entry and their detailed functions during BVDV infection. Thus, discovery of the cellular receptors involved in the entry of BVDV and other pestiviruses is significant for development of the novel intervention. The viral envelope glycoprotein Erns and E2 are crucial determinants of the cellular tropism of BVDV. The cellular proteins bound with Erns and E2 potentially participate in BVDV entry, and their abundance might determine the cellular tropism of BVDV. Here, we summarize current knowledge regarding the cellular molecules have been described for BVDV entry, such as, complement regulatory protein 46 (CD46), heparan sulfate (HS), the low-density lipoprotein (LDL) receptor, and a disintegrin and metalloproteinase 17 (ADAM17). Furthermore, we focus on their implications of the recently identified cellular receptors for pestiviruses in BVDV life cycle. This knowledge provides a theoretical basis for BVDV prevention and treatment by targeting the cellular receptors essential for BVDV infection.
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5
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DNAJC14-Independent Replication of the Atypical Porcine Pestivirus. J Virol 2022; 96:e0198021. [PMID: 35852352 PMCID: PMC9364808 DOI: 10.1128/jvi.01980-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Atypical porcine pestiviruses (APPV; Pestivirus K) are a recently discovered, very divergent species of the genus Pestivirus within the family Flaviviridae. The presence of APPV in piglet-producing farms is associated with the occurrence of so-called “shaking piglets,” suffering from mild to severe congenital tremor type A-II. Previous studies showed that the cellular protein DNAJC14 is an essential cofactor of the NS2 autoprotease of all classical pestiviruses. Consequently, genetically engineered DNAJC14 knockout cell lines were resistant to all tested noncytopathogenic (non-cp) pestiviruses. Surprisingly, we found that the non-cp APPV can replicate in these cells in the absence of DNAJC14, suggesting a divergent mechanism of polyprotein processing. A complete laboratory system for the study of APPV was established to learn more about the replication of this unusual virus. The inactivation of the APPV NS2 autoprotease using reverse genetics resulted in nonreplicative genomes. To further investigate whether a regulation of the NS2-3 cleavage is also existing in APPV, we constructed synthetic viral genomes with deletions and duplications leading to the NS2 independent release of mature NS3. As observed with other pestiviruses, the increase of mature NS3 resulted in elevated viral RNA replication levels and increased protein expression. Our data suggest that APPV exhibit a divergent mechanism for the regulation of the NS2 autoprotease activity most likely utilizing a different cellular protein for the adjustment of replication levels. IMPORTANCE DNAJC14 is an essential cofactor of the pestiviral NS2 autoprotease, limiting replication to tolerable levels as a prerequisite for the noncytopathogenic biotype of pestiviruses. Surprisingly, we found that the atypical porcine pestivirus (APPV) is able to replicate in the absence of DNAJC14. We further investigated the NS2-3 processing of APPV using a molecular clone, monoclonal antibodies, and DNAJC14 knockout cells. We identified two potential active site residues of the NS2 autoprotease and could demonstrate that the release of NS3 by the NS2 autoprotease is essential for APPV replication. Defective interfering genomes and viral genomes with duplicated NS3 sequences that produce mature NS3 independent of the NS2 autoprotease activity showed increased replication and antigen expression. It seems likely that an alternative cellular cofactor controls NS2-3 cleavage and thus replication of APPV. The replication-optimized synthetic APPV genomes might be suitable live vaccine candidates, whose establishment and testing warrant further research.
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6
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Removal of the E rns RNase Activity and of the 3' Untranslated Region Polyuridine Insertion in a Low-Virulence Classical Swine Fever Virus Triggers a Cytokine Storm and Lethal Disease. J Virol 2022; 96:e0043822. [PMID: 35758667 PMCID: PMC9327722 DOI: 10.1128/jvi.00438-22] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
In this study, we assessed the potential synergistic effect of the Erns RNase activity and the poly-U insertion in the 3′ untranslated region (UTR) of the low-virulence classical swine fever virus (CSFV) isolate Pinar de Rio (PdR) in innate and adaptive immunity regulation and its relationship with classical swine fever (CSF) pathogenesis in pigs. We knocked out the Erns RNase activity of PdR and replaced the long polyuridine sequence of the 3′ UTR with 5 uridines found typically at this position, resulting in a double mutant, vPdR-H30K-5U. This mutant induced severe CSF in 5-day-old piglets and 3-week-old pigs, with higher lethality in the newborn (89.5%) than in the older (33.3%) pigs. However, the viremia and viral excretion were surprisingly low, while the virus load was high in the tonsils. Only alpha interferon (IFN-α) and interleukin 12 (IL-12) were highly and consistently elevated in the two groups. Additionally, high IL-8 levels were found in the newborn but not in the older pigs. This points toward a role of these cytokines in the CSF outcome, with age-related differences. The disproportional activation of innate immunity might limit systemic viral spread from the tonsils and increase virus clearance, inducing strong cytokine-mediated symptoms. Infection with vPdR-H30K-5U resulted in poor neutralizing antibody responses compared with results obtained previously with the parent and RNase knockout PdR. This study shows for the first time the synergistic effect of the 3′ UTR and the Erns RNase function in regulating innate immunity against CSFV, favoring virus replication in target tissue and thus contributing to disease severity. IMPORTANCE CSF is one of the most relevant viral epizootic diseases of swine, with high economic and sanitary impact. Systematic stamping out of infected herds with and without vaccination has permitted regional virus eradication. However, the causative agent, CSFV, persists in certain areas of the world, leading to disease reemergence. Nowadays, low- and moderate-virulence strains that could induce unapparent CSF forms are prevalent, posing a challenge for disease eradication. Here, we show for the first time the synergistic role of lacking the Erns RNase activity and the 3′ UTR polyuridine insertion from a low-virulence CSFV isolate in innate immunity disproportional activation. This might limit systemic viral spread to the tonsils and increase virus clearance, inducing strong cytokine-mediated symptoms, thus contributing to disease severity. These results highlight the role played by the Erns RNase activity and the 3′ UTR in CSFV pathogenesis, providing new perspectives for novel diagnostic tools and vaccine strategies.
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7
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Gosavi D, Wower I, Beckmann IK, Hofacker IL, Wower J, Wolfinger MT, Sztuba-Solinska J. Insights into the secondary and tertiary structure of the Bovine Viral Diarrhea Virus Internal Ribosome Entry Site. RNA Biol 2022; 19:496-506. [PMID: 35380920 PMCID: PMC8986297 DOI: 10.1080/15476286.2022.2058818] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
The internal ribosome entry site (IRES) RNA of bovine viral diarrhoea virus (BVDV), an economically significant Pestivirus, is required for the cap-independent translation of viral genomic RNA. Thus, it is essential for viral replication and pathogenesis. We applied a combination of high-throughput biochemical RNA structure probing (SHAPE-MaP) and in silico modelling approaches to gain insight into the secondary and tertiary structures of BVDV IRES RNA. Our study demonstrated that BVDV IRES RNA in solution forms a modular architecture composed of three distinct structural domains (I-III). Two regions within domain III are represented in tertiary interactions to form an H-type pseudoknot. Computational modelling of the pseudoknot motif provided a fine-grained picture of the tertiary structure and local arrangement of helices in the BVDV IRES. Furthermore, comparative genomics and consensus structure predictions revealed that the pseudoknot is evolutionarily conserved among many Pestivirus species. These studies provide detailed insight into the structural arrangement of BVDV IRES RNA H-type pseudoknot and encompassing motifs that likely contribute to the optimal functionality of viral cap-independent translation element.
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Affiliation(s)
- Devadatta Gosavi
- Department of Biological Sciences, Auburn University, 120 W. Samford Ave, Rouse Life Sciences Building, Auburn, AL, United States
| | - Iwona Wower
- Department of Animal and Dairy Sciences, Auburn University, Auburn, AL, United States
| | - Irene K Beckmann
- Department of Theoretical Chemistry, University of Vienna, Vienna, Austria
| | - Ivo L Hofacker
- Department of Theoretical Chemistry, University of Vienna, Vienna, Austria.,Research Group Bioinformatics and Computational Biology, Faculty of Computer Science, University of Vienna, Vienna, Austria
| | - Jacek Wower
- Department of Animal and Dairy Sciences, Auburn University, Auburn, AL, United States
| | - Michael T Wolfinger
- Department of Theoretical Chemistry, University of Vienna, Vienna, Austria.,Research Group Bioinformatics and Computational Biology, Faculty of Computer Science, University of Vienna, Vienna, Austria
| | - Joanna Sztuba-Solinska
- Department of Biological Sciences, Auburn University, 120 W. Samford Ave, Rouse Life Sciences Building, Auburn, AL, United States.,Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznan, Poland
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8
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Development and assessment of a new bioassay for accurate quantification of Type I interferons induced by bovine respiratory viruses. J Immunol Methods 2022; 504:113256. [PMID: 35300990 DOI: 10.1016/j.jim.2022.113256] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Revised: 03/10/2022] [Accepted: 03/10/2022] [Indexed: 11/20/2022]
Abstract
Type I interferon (IFN-I) plays a major role in antiviral and inflammatory processes of the infected host. In the bovine industry, the bovine respiratory disease complex is a major cause of economic and health problems. This disease is caused by interactions of pathogens, together with environmental and host factors. Several pathogens have been identified as causal agents of respiratory diseases in cattle. To better understand how primary infections by viruses predispose animals to further infections by pathogenic bacteria, tools to accurately detect antiviral and immunoregulatory cytokines are needed. To facilitate the detection and quantification of bovine IFN-I, we have established a new specific and sensitive bioassay studies in the bovine host. This assay is based on a Madin-Darby Bovine Kidney (MDBK) cell line that carries a luciferase gene under the control of the IFN-I inducible bovine Mx1 promoter. Specific luciferase activity was measured after stimulation with serial dilutions of recombinant bovine alpha and beta IFNs and human IFN-α. With this novel bioassay we have successfully measured IFN-I production in supernatant from MDBK cells after stimulation of Toll-like receptors (TLR3, TLR7 and TLR8) and RIG-I-like receptors (RIG-I and MDA5), after viral infection with bovine respiratory pathogens, but also in samples from infected calves. Finally, this new bioassay is an easy-to-use and low cost tool to measure the production of bovine Type-I Interferon.
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9
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Lindenbach BD. Reinventing positive-strand RNA virus reverse genetics. Adv Virus Res 2022; 112:1-29. [PMID: 35840179 PMCID: PMC9273853 DOI: 10.1016/bs.aivir.2022.03.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/09/2022]
Abstract
Reverse genetics is the prospective analysis of how genotype determines phenotype. In a typical experiment, a researcher alters a viral genome, then observes the phenotypic outcome. Among RNA viruses, this approach was first applied to positive-strand RNA viruses in the mid-1970s and over nearly 50 years has become a powerful and widely used approach for dissecting the mechanisms of viral replication and pathogenesis. During this time the global health importance of two virus groups, flaviviruses (genus Flavivirus, family Flaviviridae) and betacoronaviruses (genus Betacoronavirus, subfamily Orthocoronavirinae, family Coronaviridae), have dramatically increased, yet these viruses have genomes that are technically challenging to manipulate. As a result, several new techniques have been developed to overcome these challenges. Here I briefly review key historical aspects of positive-strand RNA virus reverse genetics, describe some recent reverse genetic innovations, particularly as applied to flaviviruses and coronaviruses, and discuss their benefits and limitations within the larger context of rigorous genetic analysis.
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10
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Saied AA, Metwally AA, Mohamed HMA, Haridy MAM. The contribution of bovines to human health against viral infections. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2021; 28:46999-47023. [PMID: 34272669 PMCID: PMC8284698 DOI: 10.1007/s11356-021-14941-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Accepted: 06/12/2021] [Indexed: 04/12/2023]
Abstract
In the last 40 years, novel viruses have evolved at a much faster pace than other pathogens. Viral diseases pose a significant threat to public health around the world. Bovines have a longstanding history of significant contributions to human nutrition, agricultural, industrial purposes, medical research, drug and vaccine development, and livelihood. The life cycle, genomic structures, viral proteins, and pathophysiology of bovine viruses studied in vitro paved the way for understanding the human counterparts. Calf model has been used for testing vaccines against RSV, papillomavirus vaccines and anti-HCV agents were principally developed after using the BPV and BVDV model, respectively. Some bovine viruses-based vaccines (BPIV-3 and bovine rotaviruses) were successfully developed, clinically tried, and commercially produced. Cows, immunized with HIV envelope glycoprotein, produced effective broadly neutralizing antibodies in their serum and colostrum against HIV. Here, we have summarized a few examples of human viral infections for which the use of bovines has contributed to the acquisition of new knowledge to improve human health against viral infections covering the convergence between some human and bovine viruses and using bovines as disease models. Additionally, the production of vaccines and drugs, bovine-based products were covered, and the precautions in dealing with bovines and bovine-based materials.
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Affiliation(s)
- AbdulRahman A Saied
- Department of Food Establishments Licensing (Aswan Branch), National Food Safety Authority (NFSA), Aswan, 81511, Egypt.
- Touristic Activities and Interior Offices Sector (Aswan Office), Ministry of Tourism and Antiquities, Aswan, 81511, Egypt.
| | - Asmaa A Metwally
- Department of Surgery, Anesthesiology, and Radiology, Faculty of Veterinary Medicine, Aswan University, Aswan, 81511, Egypt
| | - Hams M A Mohamed
- Department of Microbiology, Faculty of Veterinary Medicine, South Valley University, Qena, 83523, Egypt
| | - Mohie A M Haridy
- Department of Pathology and Clinical Pathology, Faculty of Veterinary Medicine, South Valley University, Qena, 83523, Egypt.
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11
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Wang M, Bohórquez JA, Hinojosa Y, Muñoz-González S, Gerber M, Coronado L, Perera CL, Liniger M, Ruggli N, Ganges L. Abrogation of the RNase activity of E rns in a low virulence classical swine fever virus enhances the humoral immune response and reduces virulence, transmissibility, and persistence in pigs. Virulence 2021; 12:2037-2049. [PMID: 34339338 PMCID: PMC8331007 DOI: 10.1080/21505594.2021.1959715] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The prevalence of low virulence classical swine fever virus (CSFV) strains makes viral eradication difficult in endemic countries. However, the determinants for natural CSFV attenuation and persistence in the field remain unidentified. The aim of the present study was to assess the role of the RNase activity of CSFV Erns in pathogenesis, immune response, persistent infection, and viral transmission in pigs. To this end, a functional cDNA clone pPdR-H30K-36U with an Erns lacking RNase activity was constructed based on the low virulence CSFV field isolate Pinar de Rio (PdR). Eighteen 5-day-old piglets were infected with vPdR-H30K-36U. Nine piglets were introduced as contacts. The vPdR-H30K-36U virus was attenuated in piglets compared to the parental vPdR-36U. Only RNA traces were detected in sera and body secretions and no virus was isolated from tonsils, showing that RNase inactivation may reduce CSFV persistence and transmissibility. The vPdR-H30K-36U mutant strongly activated the interferon-α (IFN-α) production in plasmacytoid dendritic cells, while in vivo, the IFN-α response was variable, from moderate to undetectable depending on the animal. This suggests a role of the CSFV Erns RNase activity in the regulation of innate immune responses. Infection with vPdR-H30K-36U resulted in higher antibody levels against the E2 and Erns glycoproteins and in enhanced neutralizing antibody responses when compared with vPdR-36U. These results pave the way toward a better understanding of viral attenuation mechanisms of CSFV in pigs. In addition, they provide novel insights relevant for the development of DIVA vaccines in combination with diagnostic assays for efficient CSF control.
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Affiliation(s)
- Miaomiao Wang
- OIE Reference Laboratory for Classical Swine Fever, IRTA-CReSA, Barcelona, Spain
| | | | - Yoandry Hinojosa
- Division of Virology, Institute of Virology and Immunology IVI, Mittelhäusern, Switzerland.,Department of Infectious Diseases and Pathobiology (DIP), Vetsuisse Faculty, University of Bern, Bern, Switzerland.,Graduate School for Cellular and Biomedical Sciences (GCB), University of Bern, Bern, Switzerland.,Centro Nacional De Sanidad Agropecuaria (CENSA), Mayabeque, Cuba
| | - Sara Muñoz-González
- OIE Reference Laboratory for Classical Swine Fever, IRTA-CReSA, Barcelona, Spain
| | - Markus Gerber
- Division of Virology, Institute of Virology and Immunology IVI, Mittelhäusern, Switzerland.,Department of Infectious Diseases and Pathobiology (DIP), Vetsuisse Faculty, University of Bern, Bern, Switzerland
| | - Liani Coronado
- Centro Nacional De Sanidad Agropecuaria (CENSA), Mayabeque, Cuba
| | | | - Matthias Liniger
- Division of Virology, Institute of Virology and Immunology IVI, Mittelhäusern, Switzerland.,Department of Infectious Diseases and Pathobiology (DIP), Vetsuisse Faculty, University of Bern, Bern, Switzerland
| | - Nicolas Ruggli
- Division of Virology, Institute of Virology and Immunology IVI, Mittelhäusern, Switzerland.,Department of Infectious Diseases and Pathobiology (DIP), Vetsuisse Faculty, University of Bern, Bern, Switzerland
| | - Llilianne Ganges
- OIE Reference Laboratory for Classical Swine Fever, IRTA-CReSA, Barcelona, Spain
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12
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Reuscher CM, Schmidt L, Netsch A, Lamp B. Characterization of a Cytopathogenic Reporter CSFV. Viruses 2021; 13:1209. [PMID: 34201706 PMCID: PMC8310069 DOI: 10.3390/v13071209] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 06/16/2021] [Accepted: 06/21/2021] [Indexed: 12/30/2022] Open
Abstract
Cytopathogenic (cp) pestiviruses frequently emerge in cattle that are persistently infected with the bovine viral diarrhea virus (BVDV) as a consequence of RNA recombination and mutation. They induce apoptosis in infected tissue cultures, are highly attenuated in the immunocompetent host, and unable to establish persistent infections after diaplacental infections. Cp strains of BVDV have been used as naturally attenuated live vaccines and for species-specific plaque reduction tests for the indirect serological detection of BVDV. Here, we present a genetically engineered cp strain of the classical swine fever virus (CSFV). Cytopathogenicity of the strain was induced by the insertion of ubiquitin embedded in a large NS3 to NS4B duplication. The CSFV RNA genome was stabilized by the inactivation of the NS2 autoprotease, hindering the deletion of the insertion and the reversion to a wild-type genome. Additional insertion of a mCherry gene at the 5'-end of the E2 gene allowed fluorescence-verified plaque reduction assays for CSFV, thus providing a novel, cost-efficient diagnostic tool. This genetically stabilized cp CSFV strain could be further used as a basis for potential new modified live vaccines. Taken together, we applied reverse genetics to rationally fixate a typical cp NS3 duplication in a CSFV genome.
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Affiliation(s)
- Carina Maria Reuscher
- Institute of Virology, Faculty of Veterinary Medicine, Justus-Liebig-University, Biomedical Research Center, Schubertstrasse 81, 35392 Giessen, Germany
| | - Lisa Schmidt
- Institute of Virology, Faculty of Veterinary Medicine, Justus-Liebig-University, Biomedical Research Center, Schubertstrasse 81, 35392 Giessen, Germany
| | - Anette Netsch
- Institute of Virology, Faculty of Veterinary Medicine, Justus-Liebig-University, Biomedical Research Center, Schubertstrasse 81, 35392 Giessen, Germany
| | - Benjamin Lamp
- Institute of Virology, Faculty of Veterinary Medicine, Justus-Liebig-University, Biomedical Research Center, Schubertstrasse 81, 35392 Giessen, Germany
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13
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A β-Hairpin Motif in the Envelope Protein E2 Mediates Receptor Binding of Bovine Viral Diarrhea Virus. Viruses 2021; 13:v13061157. [PMID: 34204224 PMCID: PMC8235316 DOI: 10.3390/v13061157] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Revised: 06/09/2021] [Accepted: 06/10/2021] [Indexed: 12/29/2022] Open
Abstract
Pestivirus envelope protein E2 is crucial to virus infection and accomplishes virus-receptor interaction during entry. However, mapping of E2 residues mediating these interactions has remained unexplored. In this study, to investigate the structure-function relationship for a β-hairpin motif exposed to the solvent in the crystal structure of bovine viral diarrhea virus (BVDV) E2, we designed two amino acidic substitutions that result in a change of electrostatic potential. First, using wild type and mutant E2 expressed as soluble recombinant proteins, we found that the mutant protein had reduced binding to susceptible cells compared to wild type and diminished ability to inhibit BVDV infection, suggesting a lower affinity for BVDV receptors. We then analyzed the effect of β-hairpin mutations in the context of recombinant viral particles. Mutant viruses recovered from cell culture supernatant after transfection of recombinant RNA had almost completely inhibited ability to re-infect susceptible cells, indicating an impact of mutations on BVDV infectivity. Finally, sequential passaging of the mutant virus resulted in the selection of a viral population in which β-hairpin mutations reverted to the wild type sequence to restore infectivity. Taken together, our results show that this conserved region of the E2 protein is critical for the interaction with host cell receptors.
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14
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Hoffmann HH, Schneider WM, Rozen-Gagnon K, Miles LA, Schuster F, Razooky B, Jacobson E, Wu X, Yi S, Rudin CM, MacDonald MR, McMullan LK, Poirier JT, Rice CM. TMEM41B Is a Pan-flavivirus Host Factor. Cell 2021; 184:133-148.e20. [PMID: 33338421 PMCID: PMC7954666 DOI: 10.1016/j.cell.2020.12.005] [Citation(s) in RCA: 104] [Impact Index Per Article: 34.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Revised: 11/13/2020] [Accepted: 12/02/2020] [Indexed: 12/12/2022]
Abstract
Flaviviruses pose a constant threat to human health. These RNA viruses are transmitted by the bite of infected mosquitoes and ticks and regularly cause outbreaks. To identify host factors required for flavivirus infection, we performed full-genome loss of function CRISPR-Cas9 screens. Based on these results, we focused our efforts on characterizing the roles that TMEM41B and VMP1 play in the virus replication cycle. Our mechanistic studies on TMEM41B revealed that all members of the Flaviviridae family that we tested require TMEM41B. We tested 12 additional virus families and found that SARS-CoV-2 of the Coronaviridae also required TMEM41B for infection. Remarkably, single nucleotide polymorphisms present at nearly 20% in East Asian populations reduce flavivirus infection. Based on our mechanistic studies, we propose that TMEM41B is recruited to flavivirus RNA replication complexes to facilitate membrane curvature, which creates a protected environment for viral genome replication.
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Affiliation(s)
- H-Heinrich Hoffmann
- Laboratory of Virology and Infectious Disease, The Rockefeller University, New York, NY, USA
| | - William M Schneider
- Laboratory of Virology and Infectious Disease, The Rockefeller University, New York, NY, USA
| | - Kathryn Rozen-Gagnon
- Laboratory of Virology and Infectious Disease, The Rockefeller University, New York, NY, USA
| | - Linde A Miles
- Human Oncology & Pathogenesis Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Felix Schuster
- Laboratory of Virology and Infectious Disease, The Rockefeller University, New York, NY, USA; Institute of Virology, Medical Faculty "Carl Gustav Carus", Technische Universität Dresden, Dresden, Germany
| | - Brandon Razooky
- Laboratory of Virology and Infectious Disease, The Rockefeller University, New York, NY, USA
| | - Eliana Jacobson
- Laboratory of Virology and Infectious Disease, The Rockefeller University, New York, NY, USA
| | - Xianfang Wu
- Laboratory of Virology and Infectious Disease, The Rockefeller University, New York, NY, USA
| | - Soon Yi
- Laboratory of Virology and Infectious Disease, The Rockefeller University, New York, NY, USA
| | - Charles M Rudin
- Druckenmiller Center for Lung Cancer Research and Department of Medicine, Thoracic Oncology Service, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Margaret R MacDonald
- Laboratory of Virology and Infectious Disease, The Rockefeller University, New York, NY, USA
| | - Laura K McMullan
- Virus Special Pathogens Branch, Division of High Consequence Pathogens and Pathology, Centers of Disease Control and Prevention, Atlanta, GA, USA
| | - John T Poirier
- Laura and Isaac Perlmutter Cancer Center, New York University Langone Health, New York, NY, USA.
| | - Charles M Rice
- Laboratory of Virology and Infectious Disease, The Rockefeller University, New York, NY, USA.
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15
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Hoffmann HH, Schneider WM, Rozen-Gagnon K, Miles LA, Schuster F, Razooky B, Jacobson E, Wu X, Yi S, Rudin CM, MacDonald MR, McMullan LK, Poirier JT, Rice CM. TMEM41B is a pan-flavivirus host factor. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2020:2020.10.09.334128. [PMID: 33052348 PMCID: PMC7553181 DOI: 10.1101/2020.10.09.334128] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Flaviviruses pose a constant threat to human health. These RNA viruses are transmitted by the bite of infected mosquitoes and ticks and regularly cause outbreaks. To identify host factors required for flavivirus infection we performed full-genome loss of function CRISPR-Cas9 screens. Based on these results we focused our efforts on characterizing the roles that TMEM41B and VMP1 play in the virus replication cycle. Our mechanistic studies on TMEM41B revealed that all members of the Flaviviridae family that we tested require TMEM41B. We tested 12 additional virus families and found that SARS-CoV-2 of the Coronaviridae also required TMEM41B for infection. Remarkably, single nucleotide polymorphisms (SNPs) present at nearly twenty percent in East Asian populations reduce flavivirus infection. Based on our mechanistic studies we hypothesize that TMEM41B is recruited to flavivirus RNA replication complexes to facilitate membrane curvature, which creates a protected environment for viral genome replication. HIGHLIGHTS TMEM41B and VMP1 are required for both autophagy and flavivirus infection, however, autophagy is not required for flavivirus infection.TMEM41B associates with viral proteins and likely facilitates membrane remodeling to establish viral RNA replication complexes.TMEM41B single nucleotide polymorphisms (SNPs) present at nearly twenty percent in East Asian populations reduce flavivirus infection.TMEM41B-deficient cells display an exaggerated innate immune response upon high multiplicity flavivirus infection.
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Affiliation(s)
- H-Heinrich Hoffmann
- Laboratory of Virology and Infectious Disease, The Rockefeller University, New York, NY, USA
| | - William M Schneider
- Laboratory of Virology and Infectious Disease, The Rockefeller University, New York, NY, USA
| | - Kathryn Rozen-Gagnon
- Laboratory of Virology and Infectious Disease, The Rockefeller University, New York, NY, USA
| | - Linde A Miles
- Human Oncology & Pathogenesis Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Felix Schuster
- Laboratory of Virology and Infectious Disease, The Rockefeller University, New York, NY, USA
- Institute of Virology, Medical Faculty "Carl Gustav Carus", Technische Universität Dresden, Dresden, Germany
| | - Brandon Razooky
- Laboratory of Virology and Infectious Disease, The Rockefeller University, New York, NY, USA
| | - Eliana Jacobson
- Laboratory of Virology and Infectious Disease, The Rockefeller University, New York, NY, USA
| | - Xianfang Wu
- Laboratory of Virology and Infectious Disease, The Rockefeller University, New York, NY, USA
| | - Soon Yi
- Laboratory of Virology and Infectious Disease, The Rockefeller University, New York, NY, USA
| | - Charles M Rudin
- Druckenmiller Center for Lung Cancer Research and Department of Medicine, Thoracic Oncology Service, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Margaret R MacDonald
- Laboratory of Virology and Infectious Disease, The Rockefeller University, New York, NY, USA
| | - Laura K McMullan
- Virus Special Pathogens Branch, Division of High Consequence Pathogens and Pathology, Centers of Disease Control and Prevention, Atlanta, GA, USA
| | - John T Poirier
- Laura and Isaac Perlmutter Cancer Center, New York University Langone Health, New York, NY, USA
| | - Charles M Rice
- Laboratory of Virology and Infectious Disease, The Rockefeller University, New York, NY, USA
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16
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A Polyuridine Insertion in the 3' Untranslated Region of Classical Swine Fever Virus Activates Immunity and Reduces Viral Virulence in Piglets. J Virol 2020; 94:JVI.01214-19. [PMID: 31645448 PMCID: PMC6955259 DOI: 10.1128/jvi.01214-19] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Accepted: 10/11/2019] [Indexed: 01/15/2023] Open
Abstract
Classical swine fever (CSF), a highly contagious viral disease of pigs, is still endemic in some countries of Asia and Central and South America. Considering that the 3′ untranslated region (3′ UTR) plays an important role in flavivirus replication, the present study showed for the first time that a long polyuridine sequence acquired in the 3′ UTR by an endemic CSFV isolate can activate immunity, control viral replication, and modulate disease in piglets. Our findings provide new avenues for the development of novel vaccines against infections with CSF virus and other flaviviruses. Knowledge of molecular virulence determinants is also relevant for future development of rapid and efficient diagnostic tools for the prediction of the virulence of field isolates and for efficient CSF control. Low-virulence classical swine fever virus (CSFV) strains make CSF eradication particularly difficult. Few data are available on the molecular determinants of CSFV virulence. The aim of the present study was to assess a possible role for CSFV virulence of a unique, uninterrupted 36-uridine (poly-U) sequence found in the 3′ untranslated region (3′ UTR) of the low-virulence CSFV isolate Pinar de Rio (PdR). To this end, a pair of cDNA-derived viruses based on the PdR backbone were generated, one carrying the long poly-U insertion in the 3′ UTR (vPdR-36U) and the other harboring the standard 5 uridines at this position (vPdR-5U). Two groups of 20 5-day-old piglets were infected with vPdR-36U and vPdR-5U. Ten contact piglets were added to each group. Disease progression, virus replication, and immune responses were monitored for 5 weeks. The vPdR-5U virus was significantly more virulent than the vPdR-36U virus, with more severe disease, higher mortality, and significantly higher viral loads in serum and body secretions, despite similar replication characteristics in cell culture. The two viruses were transmitted to all contact piglets. Ninety percent of the piglets infected with vPdR-36U seroconverted, while only one vPdR-5U-infected piglet developed antibodies. The vPdR-5U-infected piglets showed only transient alpha interferon (IFN-α) responses in serum after 1 week of infection, while the vPdR-36U-infected piglets showed sustained IFN-α levels during the first 2 weeks. Taken together, these data show that the 3′ UTR poly-U insertion acquired by the PdR isolate reduces viral virulence and activates the innate and humoral immune responses without affecting viral transmission. IMPORTANCE Classical swine fever (CSF), a highly contagious viral disease of pigs, is still endemic in some countries of Asia and Central and South America. Considering that the 3′ untranslated region (3′ UTR) plays an important role in flavivirus replication, the present study showed for the first time that a long polyuridine sequence acquired in the 3′ UTR by an endemic CSFV isolate can activate immunity, control viral replication, and modulate disease in piglets. Our findings provide new avenues for the development of novel vaccines against infections with CSF virus and other flaviviruses. Knowledge of molecular virulence determinants is also relevant for future development of rapid and efficient diagnostic tools for the prediction of the virulence of field isolates and for efficient CSF control.
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17
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Tran PT, Fang M, Widyasari K, Kim KH. A plant intron enhances the performance of an infectious clone in planta. J Virol Methods 2019; 265:26-34. [PMID: 30578897 DOI: 10.1016/j.jviromet.2018.12.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2018] [Revised: 12/18/2018] [Accepted: 12/18/2018] [Indexed: 01/13/2023]
Abstract
Although infectious clones are fundamental tools in virology and plant pathology, their efficacy is often reduced by the instability of viral sequences in Escherichia coli. In this study, we constructed an infectious clone of PepMoV (pPepMoV) in a bacterial binary vector (pSNU1); the clone induces symptoms of PepMoV in agroinfiltrated plants. During its modification and maintenance in E. coli, however, the pPepMoV infectious clone was instable in the bacteria. Manipulation of this unstable clone in the bacterial strain DH10B led to the spontaneous formation of a recombined clone with high stability in the bacteria but with reduced infectivity due to an unwanted insertion of an E. coli sequence in the NIa-protease coding region. Replacement of this sequence with a plant intron restored infectivity and maintained plasmid stability. In addition to restoring plasmid growth in both E. coli and Agrobacterium, the presence of the intron in the PepMoV sequence enhanced the accumulation of PepMoV in agroinfiltrated leaves and resulted in symptom induction in upper systemic leaves that was nearly as strong as with PepMoV sap-inoculation. Plant introns have been previously used to stabilize plasmids in E. coli without any effect or with an unexpected lag in symptom development. In contrast, the current results demonstrated the in vivo enhancement of an infectious clone by a plant intron.
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Affiliation(s)
- Phu-Tri Tran
- Department of Agricultural Biotechnology, College of Agriculture and Life Sciences, Seoul National University, Seoul 08826, Republic of Korea; Plant Genomics and Breeding Institute, College of Agriculture and Life Sciences, Seoul National University, Seoul 08826, Republic of Korea
| | - Miao Fang
- Department of Agricultural Biotechnology, College of Agriculture and Life Sciences, Seoul National University, Seoul 08826, Republic of Korea
| | - Kristin Widyasari
- Department of Agricultural Biotechnology, College of Agriculture and Life Sciences, Seoul National University, Seoul 08826, Republic of Korea
| | - Kook-Hyung Kim
- Department of Agricultural Biotechnology, College of Agriculture and Life Sciences, Seoul National University, Seoul 08826, Republic of Korea; Plant Genomics and Breeding Institute, College of Agriculture and Life Sciences, Seoul National University, Seoul 08826, Republic of Korea; Research Institute of Agriculture and Life Sciences, College of Agriculture and Life Sciences, Seoul National University, Seoul 08826, Republic of Korea.
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18
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CRISPR/Cas9-Mediated Knockout of DNAJC14 Verifies This Chaperone as a Pivotal Host Factor for RNA Replication of Pestiviruses. J Virol 2019; 93:JVI.01714-18. [PMID: 30518653 DOI: 10.1128/jvi.01714-18] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Accepted: 11/20/2018] [Indexed: 12/19/2022] Open
Abstract
Pestiviruses like bovine viral diarrhea virus (BVDV) are a threat to livestock. For pestiviruses, cytopathogenic (cp) and noncytopathogenic (noncp) strains are distinguished in cell culture. The noncp biotype of BVDV is capable of establishing persistent infections, which is a major problem in disease control. The noncp biotype rests on temporal control of viral RNA replication, mediated by regulated cleavage of nonstructural protein 2-3 (NS2-3). This cleavage is catalyzed by the autoprotease in NS2, the activity of which depends on its cellular cofactor, DNAJC14. Since this chaperone is available in small amounts and binds tightly to NS2, NS2-3 translated later in infection is no longer cleaved. As NS3 is an essential constituent of the viral replicase, this shift in polyprotein processing correlates with downregulation of RNA replication. In contrast, cp BVDV strains arising mostly by RNA recombination show highly variable genome structures and display unrestricted NS3 release. The functional importance of DNAJC14 for noncp pestiviruses has been established so far only for BVDV-1. It was therefore enigmatic whether replication of other noncp pestiviruses is also DNAJC14 dependent. By generating bovine and porcine DNAJC14 knockout cells, we could show that (i) replication of 6 distinct noncp pestivirus species (A to D, F, and G) depends on DNAJC14, (ii) the pestiviral replicase NS3-5B can assemble into functional complexes in the absence of DNAJC14, and (iii) all cp pestiviruses replicate their RNA and generate infectious progeny independent of host DNAJC14. Together, these findings confirm DNAJC14 as a pivotal cellular cofactor for the replication and maintenance of the noncp biotype of pestiviruses.IMPORTANCE Only noncp pestivirus strains are capable of establishing life-long persistent infections to generate the virus reservoir in the field. The molecular basis for this biotype is only partially understood and only investigated in depth for BVDV-1 strains. Temporal control of viral RNA replication correlates with the noncp biotype and is mediated by limiting amounts of cellular DNAJC14 that activate the viral NS2 protease to catalyze the release of the essential replicase component NS3. Here, we demonstrate that several species of noncp pestiviruses depend on DNAJC14 for their RNA replication. Moreover, all cp pestiviruses, in sharp contrast to their noncp counterparts, replicate independently of DNAJC14. The generation of a cp BVDV in the persistently infected animal is causative for onset of mucosal disease. Therefore, the observed strict biotype-specific difference in DNAJC14 dependency should be further examined for its role in cell type/tissue tropism and the pathogenesis of this lethal disease.
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19
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Cell-to-Cell Transmission Is the Main Mechanism Supporting Bovine Viral Diarrhea Virus Spread in Cell Culture. J Virol 2019; 93:JVI.01776-18. [PMID: 30404802 DOI: 10.1128/jvi.01776-18] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2018] [Accepted: 10/24/2018] [Indexed: 12/30/2022] Open
Abstract
After initiation of an infective cycle, spread of virus infection can occur in two fundamentally different ways: (i) viral particles can be released into the external environment and diffuse through the extracellular space until they interact with a new host cell, and (ii) virions can remain associated with infected cells, promoting the direct passage between infected and uninfected cells that is referred to as direct cell-to-cell transmission. Although evidence of cell-associated transmission has accumulated for many different viruses, the ability of members of the genus Pestivirus to use this mode of transmission has not been reported. In the present study, we used a novel recombinant virus expressing the envelope glycoprotein E2 fused to mCherry fluorescent protein to monitor the spreading of bovine viral diarrhea virus (BVDV) (the type member of the pestiviruses) infection. To demonstrate direct cell-to-cell transmission of BVDV, we developed a cell coculture system that allowed us to prove direct transmission from infected to uninfected cells in the presence of neutralizing antibodies. This mode of transmission requires cell-cell contacts and clathrin-mediated receptor-dependent endocytosis. Notably, it overcomes antibody blocking of the BVDV receptor CD46, indicating that cell-to-cell transmission of the virus involves the engagement of coreceptors on the target cell.IMPORTANCE BVDV causes one of the most economically important viral infections for the cattle industry. The virus is able to cross the placenta and infect the fetus, leading to the birth of persistently infected animals, which are reservoirs for the spread of BVDV. The occurrence of persistent infection has hampered the efficacy of vaccination because it requires eliciting levels of protection close to sterilizing immunity to prevent fetal infections. While vaccination prevents disease, BVDV can be detected if animals with neutralizing antibodies are challenged with the virus. Virus cell-to-cell transmission allows the virus to overcome barriers to free virus dissemination, such as antibodies or epithelial barriers. Here we show that BVDV exploits cell-cell contacts to propagate infection in a process that is resistant to antibody neutralization. Our results provide new insights into the mechanisms underlying the pathogenesis of BVDV infection and can aid in the design of effective control strategies.
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20
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Lussi C, Sauter KS, Schweizer M. Homodimerisation-independent cleavage of dsRNA by a pestiviral nicking endoribonuclease. Sci Rep 2018; 8:8226. [PMID: 29844335 PMCID: PMC5974291 DOI: 10.1038/s41598-018-26557-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Accepted: 05/09/2018] [Indexed: 12/12/2022] Open
Abstract
The glycoprotein Erns plays a central role in the biology of the pestivirus bovine viral diarrhea virus (BVDV). This soluble endonuclease mediates the escape from an interferon (IFN) response in the infected fetus, thereby permitting the establishment of persistent infection. Viral single-stranded (ss) and double-stranded (ds) RNA act as potent IFN inducing signals and we previously showed that Erns efficiently cleaves these substrates, thereby inhibiting an IFN response that is crucial for successful fetal infection. Considering that a large variety of RNases and DNases require dimerisation to cleave double-stranded substrates, the activity of Erns against dsRNA was postulated to depend on homodimer formation mediated by disulfide bonds involving residue Cys171. Here, we show that monomeric Erns is equally able to cleave dsRNA and to inhibit dsRNA-induced IFN synthesis as the wild-type form. Furthermore, both forms were able to degrade RNA within a DNA/RNA- as well as within a methylated RNA/RNA-hybrid, with the DNA and the methylated RNA strand being resistant to degradation. These results support our model that Erns acts as 'nicking endoribonuclease' degrading ssRNA within double-stranded substrates. This efficiently prevents the activation of IFN and helps to maintain a state of innate immunotolerance in persistently infected animals.
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Affiliation(s)
- Carmela Lussi
- Institute of Virology and Immunology, Laenggass-Str. 122, CH-3001, Bern, Switzerland.,Department of Infectious Diseases and Pathobiology, Vetsuisse Faculty, University of Bern, Bern, Switzerland.,Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland
| | - Kay-Sara Sauter
- Institute of Virology and Immunology, Laenggass-Str. 122, CH-3001, Bern, Switzerland.,Department of Clinical Research, Faculty of Medicine, University of Bern, CH-3010, Bern, Switzerland
| | - Matthias Schweizer
- Institute of Virology and Immunology, Laenggass-Str. 122, CH-3001, Bern, Switzerland. .,Department of Infectious Diseases and Pathobiology, Vetsuisse Faculty, University of Bern, Bern, Switzerland.
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21
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Pascual MJ, Merwaiss F, Leal E, Quintana ME, Capozzo AV, Cavasotto CN, Bollini M, Alvarez DE. Structure-based drug design for envelope protein E2 uncovers a new class of bovine viral diarrhea inhibitors that block virus entry. Antiviral Res 2018; 149:179-190. [DOI: 10.1016/j.antiviral.2017.10.010] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2017] [Revised: 10/09/2017] [Accepted: 10/11/2017] [Indexed: 01/13/2023]
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22
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Ma Q, Li L, Tang Y, Fu Q, Liu S, Hu S, Qiao J, Chen C, Ni W. Analyses of long non-coding RNAs and mRNA profiling through RNA sequencing of MDBK cells at different stages of bovine viral diarrhea virus infection. Res Vet Sci 2017; 115:508-516. [PMID: 28968572 DOI: 10.1016/j.rvsc.2017.09.020] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Revised: 09/13/2017] [Accepted: 09/22/2017] [Indexed: 11/27/2022]
Abstract
BACKGROUND Bovine viral diarrhea virus (BVDV) infection is a dynamic and complex process that leads to significant economic losses in the dairy and cattle industries. However, our understanding of the protective and pathological mechanism underlying host infection is limited. METHODS To determine whether BVDV regulates specific activities of the host cell, the expression of long non-coding RNA (lncRNA) during BVDV NADL infection was studied by deep sequencing. RESULTS A total of 1236 lncRNA transcripts and 3261 mRNA transcripts were differentially regulated at 2h, 6h, and 18h post-infection. The lncRNAs shared same characteristics with other mammals in terms of exon length, number, expression level, and conservation. The Gene Ontology (GO) enrichment and KEGG pathway analyses showed that lncRNAs regulate immune reaction during BVDV infection. Thirteen differentially expressed genes in 18 hpi were selected and independently validated by reverse-transcription qPCR. CONCLUSIONS The present study is the first to provide insights into the biological connection of lncRNAs and BVDV, which can be further explored for the development of antiviral prevention strategies and in understanding persistent infection between viral and host components.
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Affiliation(s)
- Qiman Ma
- College of Medicine, Shihezi University, Shihezi, Xinjiang 832003, China
| | - Liangyuan Li
- College of Animal Science and Technology, Shihezi University, Shihezi, Xinjiang 832003, China; State Key Laboratory of Sheep Genetic Improvement and Healthy Production, Xinjiang Academy of Agricultural and Reclamation Sciences, Shihezi, Xinjiang 832000, China
| | - Yan Tang
- Animal Science and Technology Branch, Xinjiang Agricultural Vocational Technical College, Changji, Xinjiang 831100, China
| | - Qiang Fu
- College of Veterinary Medicine, Xinjiang Agricultural University, Urumqi, Xinjiang 830052, China
| | - Sheng Liu
- College of Animal Science and Technology, Shihezi University, Shihezi, Xinjiang 832003, China
| | - Shengwei Hu
- College of Life Technology, Shihezi University, Shihezi, Xinjiang 832003, China.
| | - Jun Qiao
- College of Animal Science and Technology, Shihezi University, Shihezi, Xinjiang 832003, China
| | - Chuangfu Chen
- College of Animal Science and Technology, Shihezi University, Shihezi, Xinjiang 832003, China.
| | - Wei Ni
- College of Life Technology, Shihezi University, Shihezi, Xinjiang 832003, China.
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Scheel TKH, Luna JM, Liniger M, Nishiuchi E, Rozen-Gagnon K, Shlomai A, Auray G, Gerber M, Fak J, Keller I, Bruggmann R, Darnell RB, Ruggli N, Rice CM. A Broad RNA Virus Survey Reveals Both miRNA Dependence and Functional Sequestration. Cell Host Microbe 2016; 19:409-23. [PMID: 26962949 DOI: 10.1016/j.chom.2016.02.007] [Citation(s) in RCA: 97] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Revised: 01/25/2016] [Accepted: 02/18/2016] [Indexed: 12/19/2022]
Abstract
Small non-coding RNAs have emerged as key modulators of viral infection. However, with the exception of hepatitis C virus, which requires the liver-specific microRNA (miRNA)-122, the interactions of RNA viruses with host miRNAs remain poorly characterized. Here, we used crosslinking immunoprecipitation (CLIP) of the Argonaute (AGO) proteins to characterize strengths and specificities of miRNA interactions in the context of 15 different RNA virus infections, including several clinically relevant pathogens. Notably, replication of pestiviruses, a major threat to milk and meat industries, critically depended on the interaction of cellular miR-17 and let-7 with the viral 3' UTR. Unlike canonical miRNA interactions, miR-17 and let-7 binding enhanced pestivirus translation and RNA stability. miR-17 sequestration by pestiviruses conferred reduced AGO binding and functional de-repression of cellular miR-17 targets, thereby altering the host transcriptome. These findings generalize the concept of RNA virus dependence on cellular miRNAs and connect virus-induced miRNA sequestration to host transcriptome regulation.
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Affiliation(s)
- Troels K H Scheel
- Laboratory of Virology and Infectious Disease, Center for the Study of Hepatitis C, The Rockefeller University, New York, NY 10065, USA; Copenhagen Hepatitis C Program, Department of Infectious Diseases and Clinical Research Centre, Copenhagen University Hospital, 2650 Hvidovre, Denmark; Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Joseph M Luna
- Laboratory of Virology and Infectious Disease, Center for the Study of Hepatitis C, The Rockefeller University, New York, NY 10065, USA; Laboratory of Molecular Neuro-Oncology, and Howard Hughes Medical Institute, The Rockefeller University, New York, NY 10065, USA
| | - Matthias Liniger
- Department of Virology, Institute of Virology and Immunology IVI, 3147 Mittelhäusern, Switzerland; Department of Infectious Diseases and Pathobiology, University of Bern, 3012 Bern, Switzerland
| | - Eiko Nishiuchi
- Laboratory of Virology and Infectious Disease, Center for the Study of Hepatitis C, The Rockefeller University, New York, NY 10065, USA
| | - Kathryn Rozen-Gagnon
- Laboratory of Virology and Infectious Disease, Center for the Study of Hepatitis C, The Rockefeller University, New York, NY 10065, USA
| | - Amir Shlomai
- Laboratory of Virology and Infectious Disease, Center for the Study of Hepatitis C, The Rockefeller University, New York, NY 10065, USA
| | - Gaël Auray
- Department of Virology, Institute of Virology and Immunology IVI, 3147 Mittelhäusern, Switzerland; Department of Infectious Diseases and Pathobiology, University of Bern, 3012 Bern, Switzerland
| | - Markus Gerber
- Department of Virology, Institute of Virology and Immunology IVI, 3147 Mittelhäusern, Switzerland; Department of Infectious Diseases and Pathobiology, University of Bern, 3012 Bern, Switzerland
| | - John Fak
- Laboratory of Molecular Neuro-Oncology, and Howard Hughes Medical Institute, The Rockefeller University, New York, NY 10065, USA
| | - Irene Keller
- Interfaculty Bioinformatics Unit and Swiss Institute of Bioinformatics, University of Bern, 3012 Bern, Switzerland
| | - Rémy Bruggmann
- Interfaculty Bioinformatics Unit and Swiss Institute of Bioinformatics, University of Bern, 3012 Bern, Switzerland
| | - Robert B Darnell
- Laboratory of Molecular Neuro-Oncology, and Howard Hughes Medical Institute, The Rockefeller University, New York, NY 10065, USA; New York Genome Center, New York, NY 10013, USA
| | - Nicolas Ruggli
- Department of Virology, Institute of Virology and Immunology IVI, 3147 Mittelhäusern, Switzerland; Department of Infectious Diseases and Pathobiology, University of Bern, 3012 Bern, Switzerland
| | - Charles M Rice
- Laboratory of Virology and Infectious Disease, Center for the Study of Hepatitis C, The Rockefeller University, New York, NY 10065, USA.
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24
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Tao J, Liao J, Wang J, Zhang X, Zhang Q, Zhu L, Zhang W, Liu H, Zhu G. Pig BVDV-2 non-structural protein (N pro) links to cellular antiviral response in vitro. Virus Genes 2016; 53:233-239. [PMID: 27866318 DOI: 10.1007/s11262-016-1410-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Accepted: 11/10/2016] [Indexed: 10/20/2022]
Abstract
In this study, we constructed for the first time a full-length cDNA clone of pig-original bovine viral diarrhea virus 2 (BVDV-2) strain SH-28, modified the cDNA clone (pASH28) for mutant pASHΔNpro and derived virus strain vASHΔNpro by deleting the genomic region encoding the Npro polypeptide, and examined significance of protein Npro for antiviral responses in vitro. Data showed that Npro-deletion mutant virus vASHΔNpro led to significant overexpression of oligo adenylate synthetase (OAS), myxovirus-resistant protein 1 (Mx1), and ubiquitin-like protein 15 (ISG15). Data also revealed that overexpression of Npro, but not NS2 and NS3 proteins, resulted in significant down-regulation of OAS, Mx1, and ISG15 production (p ≤ 0.05) in bovine cells as well as porcine cells transfected with Npro recombinant eukaryotic expression plasmids. Npro (but not NS2 and NS3) was also found to inhibit poly(IC) from inducing production of type I interferon (IFN-I). These results indicated that protein Npro may play multiple roles in regulating antiviral response in host cells interfered by pig BVDV-2 strain, and provided useful information to understand better the mechanism of BVDV-2 persistent infection in pigs.
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Affiliation(s)
- Jie Tao
- College of Veterinary Medicine, and Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, 225009, China.,Institute of Animal Sciences and Veterinary Medicine, Shanghai Academy of Agricultural Sciences, Shanghai, 201106, China
| | - Jinhu Liao
- College of Veterinary Medicine, and Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, 225009, China
| | - Jianye Wang
- College of Veterinary Medicine, and Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, 225009, China
| | - Xinjun Zhang
- College of Veterinary Medicine, and Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, 225009, China
| | - Qian Zhang
- College of Veterinary Medicine, and Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, 225009, China
| | - Liqian Zhu
- College of Veterinary Medicine, and Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, 225009, China
| | - Weiping Zhang
- College of Veterinary Medicine, Kansas State University, Manhattan, KS, 66506, USA
| | - Huili Liu
- Institute of Animal Sciences and Veterinary Medicine, Shanghai Academy of Agricultural Sciences, Shanghai, 201106, China
| | - Guoqiang Zhu
- College of Veterinary Medicine, and Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, 225009, China.
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25
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Li L, Pang H, Wu R, Zhang Y, Tan Y, Pan Z. Development of a novel single-step reverse genetics system for the generation of classical swine fever virus. Arch Virol 2016; 161:1831-8. [DOI: 10.1007/s00705-016-2851-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Accepted: 03/31/2016] [Indexed: 12/21/2022]
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26
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Callens N, Brügger B, Bonnafous P, Drobecq H, Gerl MJ, Krey T, Roman-Sosa G, Rümenapf T, Lambert O, Dubuisson J, Rouillé Y. Morphology and Molecular Composition of Purified Bovine Viral Diarrhea Virus Envelope. PLoS Pathog 2016; 12:e1005476. [PMID: 26939061 PMCID: PMC4777508 DOI: 10.1371/journal.ppat.1005476] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2015] [Accepted: 02/07/2016] [Indexed: 11/17/2022] Open
Abstract
The family Flaviviridae includes viruses that have different virion structures and morphogenesis mechanisms. Most cellular and molecular studies have been so far performed with viruses of the Hepacivirus and Flavivirus genera. Here, we studied bovine viral diarrhea virus (BVDV), a member of the Pestivirus genus. We set up a method to purify BVDV virions and analyzed their morphology by electron microscopy and their protein and lipid composition by mass spectrometry. Cryo-electron microscopy showed near spherical viral particles displaying an electron-dense capsid surrounded by a phospholipid bilayer with no visible spikes. Most particles had a diameter of 50 nm and about 2% were larger with a diameter of up to 65 nm, suggesting some size flexibility during BVDV morphogenesis. Morphological and biochemical data suggested a low envelope glycoprotein content of BVDV particles, E1 and E2 being apparently less abundant than Erns. Lipid content of BVDV particles displayed a ~2.3 to 3.5-fold enrichment in cholesterol, sphingomyelin and hexosyl-ceramide, concomitant with a 1.5 to 5-fold reduction of all glycerophospholipid classes, as compared to lipid content of MDBK cells. Although BVDV buds in the endoplasmic reticulum, its lipid content differs from a typical endoplasmic reticulum membrane composition. This suggests that BVDV morphogenesis includes a mechanism of lipid sorting. Functional analyses confirmed the importance of cholesterol and sphingomyelin for BVDV entry. Surprisingly, despite a high cholesterol and sphingolipid content of BVDV envelope, E2 was not found in detergent-resistant membranes. Our results indicate that there are differences between the structure and molecular composition of viral particles of Flaviviruses, Pestiviruses and Hepaciviruses within the Flaviviridae family. Bovine viral diarrhea virus (BVDV) is the etiologic agent of mucosal disease and bovine viral diarrhea, two economically important diseases of the livestock. BVDV is a member of the Pestivirus genus in the Flaviviridae family, which also includes Hepacivirus and Flavivirus genera. Members of this family share similar genome organization and replication strategies, but differ about their mode of transmission and particle structure. Whereas most studies have been so far performed on viruses of the Hepacivirus and Flavivirus genera, little is known about infectious particles of pestiviruses. In this study, we set up a novel purification method of BVDV infectious particles and analyzed their morphology by cryo-electron microscopy and their molecular composition by mass spectrometry. Our results provide new insights into the structure and biochemical composition of a pestivirus infectious particle, and have implications for research on molecular mechanisms of their morphogenesis and entry.
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Affiliation(s)
- Nathalie Callens
- Univ. Lille, CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, U1019-UMR 8204-CIIL-Center for Infection and Immunity of Lille, Lille, France
| | - Britta Brügger
- Heidelberg University Biochemistry Center, INF 328, Heidelberg, Germany
| | - Pierre Bonnafous
- Institut de Chimie et Biologie des Membranes et des Nano-objets, CNRS UMR-5248, Université de Bordeaux, Pessac, France
| | - Hervé Drobecq
- Univ. Lille, CNRS, Institut Pasteur de Lille, UMR 8161-M3T-Mechanisms of Tumorigenesis and Target Therapies, Lille, France
| | - Mathias J Gerl
- Heidelberg University Biochemistry Center, INF 328, Heidelberg, Germany
| | - Thomas Krey
- Institut Pasteur, Unité de Virologie Structurale, Département de Virologie, Paris, France.,CNRS UMR 3569, 25-28 Rue du Docteur Roux, Paris Cedex 15, France
| | - Gleyder Roman-Sosa
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut (FLI), 17493 Greifswald-Insel Riems, Germany
| | - Till Rümenapf
- Institute of Virology, University of Veterinary Medicine, Vienna, Austria
| | - Olivier Lambert
- Institut de Chimie et Biologie des Membranes et des Nano-objets, CNRS UMR-5248, Université de Bordeaux, Pessac, France
| | - Jean Dubuisson
- Univ. Lille, CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, U1019-UMR 8204-CIIL-Center for Infection and Immunity of Lille, Lille, France
| | - Yves Rouillé
- Univ. Lille, CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, U1019-UMR 8204-CIIL-Center for Infection and Immunity of Lille, Lille, France
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27
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Li L, Wu R, Zheng F, Zhao C, Pan Z. The N-terminus of classical swine fever virus (CSFV) nonstructural protein 2 modulates viral genome RNA replication. Virus Res 2015; 210:90-9. [PMID: 26232654 DOI: 10.1016/j.virusres.2015.07.021] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2015] [Revised: 07/17/2015] [Accepted: 07/21/2015] [Indexed: 10/23/2022]
Abstract
Pestivirus nonstructural protein 2 (NS2) is a multifunctional, hydrophobic protein with an important but poorly understood role in viral RNA replication and infectious virus production. In the present study, based on sequence analysis, we mutated several representative conserved residues within the N-terminus of NS2 of classical swine fever virus (CSFV) and investigated how these mutations affected viral RNA replication and infectious virus production. Our results demonstrated that the mutation of two aspartic acids, NS2/D60A or NS2/D60K and NS2/D78K, in the N-terminus of NS2 abolished infectious virus production and that the substitution of arginine for alanine at position 100 (NS2/R100A) resulted in significantly decreased viral titer. The serial passage of cells containing viral genomic RNA molecules generated the revertants NS2/A60D, NS2/K60D and NS2/K78D, leading to the recovery of infectious virus. In the context of the NS2/R100A mutant, the NS2/I90L mutation compensated for infectious virus production. The regulatory roles of the indicated amino acid residues were identified to occur at the viral RNA replication level. These results revealed a novel function for the NS2 N-terminus of CSFV in modulating viral RNA replication.
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Affiliation(s)
- Ling Li
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Rui Wu
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Fengwei Zheng
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Cheng Zhao
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Zishu Pan
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China.
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28
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Zhang YY, Hu KQ. Rethinking the pathogenesis of hepatitis B virus (HBV) infection. J Med Virol 2015; 87:1989-99. [PMID: 25989114 DOI: 10.1002/jmv.24270] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2015] [Revised: 05/05/2015] [Accepted: 05/10/2015] [Indexed: 12/11/2022]
Abstract
Chronic hepatitis B virus (HBV) infection affects approximately 375 million people worldwide. Current antiviral treatment effectively controls, but rarely clears chronic HBV infection. In addition, a significant portion of chronic HBV infected patients are not suitable for currently available antiviral therapy, and still face higher risk for cirrhosis and hepatocellular carcinoma. The poorly understood pathogenesis of HBV infection is the main barrier for developing more effective treatment strategies. HBV has long been viewed as non-cytopathic and the central hypothesis for HBV pathogenesis lies in the belief that hepatitis B is a host specific immunity-mediated liver disease. However, this view has been challenged by the accumulating experimental and clinical data that support a model of cytopathic HBV replication. In this article we systematically review the pathogenic role of HBV replication in hepatitis B and suggest possible HBV replication related mechanisms for HBV-mediated liver injury. We propose that a full understanding of HBV pathogenesis should consider the following elements. I. Liver injury can be caused by high levels of HBV replication and accumulation of viral products in the infected hepatocytes. II. HBV infection can be either directly cytopathic, non-cytopathic, or a mix of both in an individual patient depending upon accumulation levels of viral products that are usually associated with HBV replication activity in individual infected hepatocytes.
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Affiliation(s)
| | - Ke-Qin Hu
- Division of Gastroenterology and Hepatology, University of California, Irvine Medical Center, Orange, California
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29
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Abstract
Pestiviruses are among the economically most important pathogens of livestock. The biology of these viruses is characterized by unique and interesting features that are both crucial for their success as pathogens and challenging from a scientific point of view. Elucidation of these features at the molecular level has made striking progress during recent years. The analyses revealed that major aspects of pestivirus biology show significant similarity to the biology of human hepatitis C virus (HCV). The detailed molecular analyses conducted for pestiviruses and HCV supported and complemented each other during the last three decades resulting in elucidation of the functions of viral proteins and RNA elements in replication and virus-host interaction. For pestiviruses, the analyses also helped to shed light on the molecular basis of persistent infection, a special strategy these viruses have evolved to be maintained within their host population. The results of these investigations are summarized in this chapter.
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Affiliation(s)
- Norbert Tautz
- Institute for Virology and Cell Biology, University of Lübeck, Lübeck, Germany
| | - Birke Andrea Tews
- Institut für Immunologie, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Greifswald-Insel Riems, Germany
| | - Gregor Meyers
- Institut für Immunologie, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Greifswald-Insel Riems, Germany.
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30
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Shubin AV, Demidyuk IV, Lunina NA, Komissarov AA, Roschina MP, Leonova OG, Kostrov SV. Protease 3C of hepatitis A virus induces vacuolization of lysosomal/endosomal organelles and caspase-independent cell death. BMC Cell Biol 2015; 16:4. [PMID: 25886889 PMCID: PMC4355371 DOI: 10.1186/s12860-015-0050-z] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2014] [Accepted: 01/26/2015] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND 3C proteases, the main proteases of picornaviruses, play the key role in viral life cycle by processing polyproteins. In addition, 3C proteases digest certain host cell proteins to suppress antiviral defense, transcription, and translation. The activity of 3C proteases per se induces host cell death, which makes them critical factors of viral cytotoxicity. To date, cytotoxic effects have been studied for several 3C proteases, all of which induce apoptosis. This study for the first time describes the cytotoxic effect of 3C protease of human hepatitis A virus (3Cpro), the only proteolytic enzyme of the virus. RESULTS Individual expression of 3Cpro induced catalytic activity-dependent cell death, which was not abrogated by the pan-caspase inhibitor (z-VAD-fmk) and was not accompanied by phosphatidylserine externalization in contrast to other picornaviral 3C proteases. The cell survival was also not affected by the inhibitors of cysteine proteases (z-FA-fmk) and RIP1 kinase (necrostatin-1), critical enzymes involved in non-apoptotic cell death. A substantial fraction of dying cells demonstrated numerous non-acidic cytoplasmic vacuoles with not previously described features and originating from several types of endosomal/lysosomal organelles. The lysosomal protein Lamp1 and GTPases Rab5, Rab7, Rab9, and Rab11 were associated with the vacuolar membranes. The vacuolization was completely blocked by the vacuolar ATPase inhibitor (bafilomycin A1) and did not depend on the activity of the principal factors of endosomal transport, GTPases Rab5 and Rab7, as well as on autophagy and macropinocytosis. CONCLUSIONS 3Cpro, apart from other picornaviral 3C proteases, induces caspase-independent cell death, accompanying by cytoplasmic vacuolization. 3Cpro-induced vacuoles have unique properties and are formed from several organelle types of the endosomal/lysosomal compartment. The data obtained demonstrate previously undocumented morphological characters of the 3Cpro-induced cell death, which can reflect unknown aspects of the human hepatitis A virus-host cell interaction.
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Affiliation(s)
- Andrey V Shubin
- Laboratory of Protein Engineering, Institute of Molecular Genetics, Russian Academy of Science, Moscow, 123182, Russia.
| | - Ilya V Demidyuk
- Laboratory of Protein Engineering, Institute of Molecular Genetics, Russian Academy of Science, Moscow, 123182, Russia.
| | - Nataliya A Lunina
- Laboratory of Protein Engineering, Institute of Molecular Genetics, Russian Academy of Science, Moscow, 123182, Russia.
| | - Alexey A Komissarov
- Laboratory of Protein Engineering, Institute of Molecular Genetics, Russian Academy of Science, Moscow, 123182, Russia.
| | - Marina P Roschina
- Laboratory of Protein Engineering, Institute of Molecular Genetics, Russian Academy of Science, Moscow, 123182, Russia.
| | - Olga G Leonova
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow, 119992, Russia.
| | - Sergey V Kostrov
- Laboratory of Protein Engineering, Institute of Molecular Genetics, Russian Academy of Science, Moscow, 123182, Russia.
- National Research Center "Kurchatov Institute", Moscow, 123182, Russia.
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31
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Fu Q, Shi H, Shi M, Meng L, Bao H, Zhang G, Ren Y, Zhang H, Guo F, Qiao J, Jia B, Wang P, Ni W, Sheng J, Chen C. Roles of bovine viral diarrhea virus envelope glycoproteins in inducing autophagy in MDBK cells. Microb Pathog 2014; 76:61-6. [DOI: 10.1016/j.micpath.2014.09.011] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2014] [Revised: 09/16/2014] [Accepted: 09/18/2014] [Indexed: 01/07/2023]
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Arenhart S, Flores EF, Weiblen R, Gil LHVG. Insertion and stable expression of Gaussia luciferase gene by the genome of bovine viral diarrhea virus. Res Vet Sci 2014; 97:439-48. [PMID: 25108838 DOI: 10.1016/j.rvsc.2014.07.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2013] [Revised: 06/29/2014] [Accepted: 07/08/2014] [Indexed: 11/16/2022]
Abstract
As a tool to address selected issues of virus biology, we constructed a recombinant cDNA clone of bovine viral diarrhea virus (BVDV) expressing Gaussia luciferase (Gluc) reporter gene. A full-length genomic cDNA clone of a non-cytopathic BVDV isolate was assembled by recombination in yeast Saccharomyces cerevisiae. The Gluc gene was inserted between the N(pro) and Core protein coding regions by recombination. The cDNA transcribed in vitro was infectious upon transfection of MDBK cells, resulting in reporter gene expression and productive virus replication. The rescued viruses were stable for 15 passages in cell culture, maintaining the replication kinetics, focus size and morphology similar to those of the parental virus. Expression and correct processing of the reporter protein were also maintained, as demonstrated by Gluc activity. These results demonstrate that genes up to 555 bp are simply assembled by a single step in yeast recombination and are stably expressed by this cDNA clone.
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Affiliation(s)
- S Arenhart
- Laboratório de Virologia e Terapia Experimental (LaViTE), Departamento de Virologia e Terapia Experimental, Centro de Pesquisas Aggeu Magalhães (CPqAM), Fundação Oswaldo Cruz (Fiocruz), Recife, PE 50670-420, Brasil; Setor de Virologia (SV), Departamento de Medicina Veterinária Preventiva (DMVP), Centro de Ciências Rurais (CCR), Universidade Federal de Santa Maria, Santa Maria, RS 97105-900, Brasil
| | - E F Flores
- Setor de Virologia (SV), Departamento de Medicina Veterinária Preventiva (DMVP), Centro de Ciências Rurais (CCR), Universidade Federal de Santa Maria, Santa Maria, RS 97105-900, Brasil
| | - R Weiblen
- Setor de Virologia (SV), Departamento de Medicina Veterinária Preventiva (DMVP), Centro de Ciências Rurais (CCR), Universidade Federal de Santa Maria, Santa Maria, RS 97105-900, Brasil
| | - L H V G Gil
- Laboratório de Virologia e Terapia Experimental (LaViTE), Departamento de Virologia e Terapia Experimental, Centro de Pesquisas Aggeu Magalhães (CPqAM), Fundação Oswaldo Cruz (Fiocruz), Recife, PE 50670-420, Brasil.
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33
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Bovine viral diarrhea virus infection induces autophagy in MDBK cells. J Microbiol 2014; 52:619-25. [DOI: 10.1007/s12275-014-3479-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2013] [Revised: 02/20/2014] [Accepted: 04/05/2014] [Indexed: 01/07/2023]
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Castro EF, Campos RH, Cavallaro LV. Stability of the resistance to the thiosemicarbazone derived from 5,6-dimethoxy-1-indanone, a non-nucleoside polymerase inhibitor of bovine viral diarrhea virus. PLoS One 2014; 9:e100528. [PMID: 24950191 PMCID: PMC4065067 DOI: 10.1371/journal.pone.0100528] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2014] [Accepted: 05/28/2014] [Indexed: 12/03/2022] Open
Abstract
Bovine viral diarrhea virus (BVDV) is the prototype Pestivirus. BVDV infection is distributed worldwide and causes serious problems for the livestock industry. The thiosemicarbazone of 5,6-dimethoxy-1-indanone (TSC) is a non-nucleoside polymerase inhibitor (NNI) of BVDV. All TSC-resistant BVDV variants (BVDV-TSCr T1–5) present an N264D mutation in the NS5B gene (RdRp) whereas the variant BVDV-TSCr T1 also presents an NS5B A392E mutation. In the present study, we carried out twenty passages of BVDV-TSCr T1–5 in MDBK cells in the absence of TSC to evaluate the stability of the resistance. The viral populations obtained (BVDV R1–5) remained resistant to the antiviral compound and conserved the mutations in NS5B associated with this phenotype. Along the passages, BVDV R2, R3 and R5 presented a delay in the production of cytopathic effect that correlated with a decrease in cell apoptosis and intracellular accumulation of viral RNA. The complete genome sequences that encode for NS2 to NS5B, Npro and Erns were analyzed. Additional mutations were detected in the NS5B of BVDV R1, R3 and R4. In both BVDV R2 and R3, most of the mutations found were localized in NS5A, whereas in BVDV R5, the only mutation fixed was NS5A V177A. These results suggest that mutations in NS5A could alter BVDV cytopathogenicity. In conclusion, the stability of the resistance to TSC may be due to the fixation of different compensatory mutations in each BVDV-TSCr. During their replication in a TSC-free medium, some virus populations presented a kind of interaction with the host cell that resembled a persistent infection: decreased cytopathogenicity and viral genome synthesis. This is the first report on the stability of antiviral resistance and on the evolution of NNI-resistant BVDV variants. The results obtained for BVDV-TSCr could also be applied for other NNIs.
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Affiliation(s)
- Eliana F. Castro
- Cátedra de Virología, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Rodolfo H. Campos
- Cátedra de Virología, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Lucía V. Cavallaro
- Cátedra de Virología, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Buenos Aires, Argentina
- * E-mail:
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Mucosal disease-like syndrome in a calf persistently infected by Hobi-like pestivirus. J Clin Microbiol 2014; 52:2946-54. [PMID: 24899039 DOI: 10.1128/jcm.00986-14] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A calf persistently infected with Hobi-like pestivirus displayed severe clinical signs and subsequently died. Gross lesions and histopathological changes were suggestive of hemorrhagic and necrotic inflammation involving several tissues. A Hobi-like pestivirus pair was isolated from the dead calf, i.e., cytopathogenic (CP) and noncytopathogenic (NCP) strains strictly related to each other and to Italian prototype isolates at the genetic level. Two biotype-specific real-time reverse transcription-PCR assays determined the time of the emergence of the CP virus as 1 month before the calf's death. This highest RNA titers were reached in lymphoid and nervous system tissues, whereas only traces of CP viral RNA were found in blood. In contrast, great NCP virus loads were present in all tissues and biological fluids. The present report provides new insights into the pathogenesis and molecular mechanisms of this emerging group of pestiviruses.
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Gebauer M, Behrens M, König M, Behrens SE. A bi-cistronic, reporter-encoding bovine viral diarrhea virus applied in a new, effective diagnostic test. J Gen Virol 2014; 95:1522-1531. [PMID: 24760759 DOI: 10.1099/vir.0.063800-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Infections with bovine viral diarrhea virus (BVDV) have a huge economic impact on cattle production and reproduction worldwide. A key factor for BVDV surveillance and eventual eradication is to efficiently detect infections and to monitor herd immunity. In this study, we generated a stable, bi-cistronic BVDV that encoded EGFP in addition to the viral proteins. Applying this recombinant virus, a new flow-cytometry-based virus neutralization test was established that enabled accurate and reliable detection of field-virus-infected and vaccinated animals. The test, which is simple and fast, is expected to support novel, effective screening procedures in eradication and vaccination programmes.
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Affiliation(s)
- Mandy Gebauer
- Institute of Biochemistry and Biotechnology, Faculty of Life Sciences (NFI), Martin Luther University Halle-Wittenberg, Halle, Germany
| | - Martina Behrens
- Institute of Biochemistry and Biotechnology, Faculty of Life Sciences (NFI), Martin Luther University Halle-Wittenberg, Halle, Germany
| | - Matthias König
- Institue of Virology, Faculty of Veterinary Medicine, Justus-Liebig-University Giessen, Giessen, Germany
| | - Sven-Erik Behrens
- Institute of Biochemistry and Biotechnology, Faculty of Life Sciences (NFI), Martin Luther University Halle-Wittenberg, Halle, Germany
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Fu Q, Shi H, Zhang H, Ren Y, Guo F, Qiao J, Jia B, Wang P, Chen C. Autophagy during early stages contributes to bovine viral diarrhea virus replication in MDBK cells. J Basic Microbiol 2013; 54:1044-52. [PMID: 24347372 DOI: 10.1002/jobm.201300750] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2013] [Accepted: 11/16/2013] [Indexed: 12/18/2022]
Abstract
Autophagy (or autophagocytosis) is an essential and precise control process by which cells degrade unnecessary or dysfunctional cellular components or organelles in the cytoplasm in response to nutrient depletion, exogenous pathogens, or other stimuli. This process results in the removal of damaged or surplus organelles and macromolecular complexes via a lysosome-dependent mechanism. Bovine viral diarrhea virus (BVDV) is a ssRNA virus of the Flaviviridae family (genus Pestivirus). BVDV infection results in major economic losses due to poor reproductive performance and poor calf performance in cattle herds. In our previous studies, we have shown that BVDV NADL infection significantly increases autophagy in MDBK cells. To further define the interactions between autophagy and BVDV infection, we investigated the effects of autophagy on the replication of BVDV NADL. The findings showed that autophagy was inhibited by treatment with 3-methyladenine (3-MA) or wortmannin and that the knockdown of LC3 and Beclin1 using lentivirus-mediated RNA interference (RNAi) suppressed BVDV NADL replication. In contrast, the findings showed the replication of BVDV NADL was significantly increased by treatment with the autophagy inducer rapamycin within 18 h post-infection (pi). However, the mRNA levels of BVDV NADL 5'UTRs showed a downward trend after 18 h pi, and this effect was reversed by chloroquine treatment. Therefore, we inferred that infection with BVDV NADL increases autophagy, which in turn favors BVDV NADL replication at early stages.
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Affiliation(s)
- Qiang Fu
- College of Animal Science and Technology, Shihezi University, Shihezi, 832003, Xinjiang, People's Republic of China
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Abstract
Pestiviruses cause economically important diseases among domestic ruminants and pigs, but they may also infect a wide spectrum of wild species of even-toed ungulates (Artiodactyla). Bovine viral diarrhea virus (BVDV) and Border disease virus of sheep infect their hosts either transiently or persistently. Cellular and humoral immunotolerance to the infecting strain is a unique feature of persistent infection (PI) by ruminant pestiviruses. Persistence, caused by transplacental infection early in fetal development, depends on virally encoded interferon antagonists that inactivate the host's innate immune response to the virus without globally interfering with its function against other viruses. At epidemiological equilibrium, approximately 1-2% of animals are PI. Successful BVDV control programs show that removal of PI animals results in viral extinction in the host population. The nucleotide sequences of ruminant pestiviruses change little during persistent infection. Nevertheless, they display large heterogeneity, pointing to a long history of virus-host coevolution in which avirulent strains are more successful.
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Affiliation(s)
- Matthias Schweizer
- Institute of Veterinary Virology, University of Bern, CH-3001 Bern, Switzerland; ,
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Molecular biology of bovine viral diarrhea virus. Biologicals 2013; 41:2-7. [DOI: 10.1016/j.biologicals.2012.07.002] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2012] [Revised: 06/27/2012] [Accepted: 07/06/2012] [Indexed: 11/21/2022] Open
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Henningson JN, Steffen DJ, Topliff CL, Kurth KL, Dubielzig RR, Brodersen BW, Bedenice D, Eskridge KM, Callan RJ, Reggiardo C, Rupp GP, Kelling CL. Systemic Distribution of Viral Antigen in Alpacas Persistently Infected With Bovine Pestivirus. Vet Pathol 2012; 50:308-17. [DOI: 10.1177/0300985812447827] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Recently, confirmed occurrences of persistent bovine viral diarrhea virus (BVDV) infection in North American alpacas have raised concerns about the role of persistently infected (PI) alpacas in transmission of virus among herds, yet only limited pathological descriptions of persistent infections in alpacas have been reported. The objective of this study was to characterize BVDV antigen distribution in 10 PI alpacas of varying age and to compare viral antigen distribution and localization in tissues of PI alpacas with 5 PI calves of varying age. Ocular dysplasia was evident in 1 PI alpaca, constituting the first reported congenital ocular lesion in PI alpacas. Viral antigen was widely distributed in alpaca tissues and was prominent in neurons, endothelial cells, and vascular tunica media myocytes but had limited distribution in lymphoid tissues and moderate distribution in epithelium of several organ systems of alpacas. Macrophages in the alpaca gastrointestinal system submucosa and lymph node medullary sinuses often had prominent labeling. In addition, only 1 alpaca had antigen labeling in the bone marrow in contrast to PI cattle. Labeled cells in calf tissues were more widely distributed, occurring prominently in lymphoid and epithelial tissues. Common features of the 2 host species were widespread antigen labeling and absence of lymphoid depletion.
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Affiliation(s)
- J. N. Henningson
- School of Veterinary Medicine and Biomedical
Sciences, University of Nebraska, Lincoln, Nebraska
- Current address: Kansas State Veterinary
Diagnostic Laboratory, Kansas State University, Manhattan, Kansas
| | - D. J. Steffen
- School of Veterinary Medicine and Biomedical
Sciences, University of Nebraska, Lincoln, Nebraska
| | - C. L. Topliff
- School of Veterinary Medicine and Biomedical
Sciences, University of Nebraska, Lincoln, Nebraska
| | - K. L. Kurth
- Wisconsin Veterinary Diagnostic Laboratory,
Madison, Wisconsin
| | - R. R. Dubielzig
- Department of Pathobiology, University of
Wisconsin School of Veterinary Medicine, Madison, Wisconsin
| | - B. W. Brodersen
- School of Veterinary Medicine and Biomedical
Sciences, University of Nebraska, Lincoln, Nebraska
| | - D. Bedenice
- Cummings School of Veterinary Medicine, Tufts
University, North Grafton, Massachusetts
| | - K. M. Eskridge
- Department of Statistics, University of
Nebraska, Lincoln, Nebraska
| | - R. J. Callan
- College of Veterinary Medicine, Colorado State
University, Fort Collins, Colorado
| | - C. Reggiardo
- Arizona Veterinary Diagnostic Laboratory,
University of Arizona, Tucson, Arizona
| | - G. P. Rupp
- School of Veterinary Medicine and Biomedical
Sciences, University of Nebraska, Lincoln, Nebraska
| | - C. L. Kelling
- School of Veterinary Medicine and Biomedical
Sciences, University of Nebraska, Lincoln, Nebraska
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41
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Development of a reporter bovine viral diarrhea virus and initial evaluation of its application for high throughput antiviral drug screening. J Virol Methods 2011; 180:54-61. [PMID: 22227616 DOI: 10.1016/j.jviromet.2011.12.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2011] [Revised: 12/15/2011] [Accepted: 12/22/2011] [Indexed: 11/21/2022]
Abstract
Bovine viral diarrhea virus (BVDV) causes lethal mucosal disease of cattle and leads to severe economic loss of cattle production and reproduction worldwide. Over the past decades, vaccination was not very successful in providing prevention of BVDV infection. This reality demands that anti-BVDV drugs should be used as an alternative treatment strategy. In this study, a BAC cDNA of noncytopathic BVDV strain SD-1 is constructed to contain an enhanced green fluorescence protein (eGFP) gene between viral NS3 and NS4A coding sequences. The recombinant reporter virus is generated subsequently by transfection of MDBK cells with the transcripts produced in vitro. The rescued reporter virus is stable in MDBK cells and the eGFP protein is expressed and processed properly. Of most importance, the reporter virus shows a growth property similar to the SD-1 parent and the fluorescent signal intensity increases in parallel to the reporter virus RNA and protein replication. In addition, two known anti-BVDV drug G418 (viral assembly/release inhibitor) and ribavirin (viral RNA replication inhibitor) are identified as hits in a high-throughput format, suggesting that this system is capable of identifying BVDV inhibitors that target different steps in viral life cycle. The cell-based system developed provides a useful and versatile tool which should facilitate the identification of BVDV inhibitors on a large scale.
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Gao Y, Wang S, Du R, Wang Q, Sun C, Wang N, Zhang P, Zhang L. Isolation and identification of a bovine viral diarrhea virus from sika deer in china. Virol J 2011; 8:83. [PMID: 21352530 PMCID: PMC3052189 DOI: 10.1186/1743-422x-8-83] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2011] [Accepted: 02/25/2011] [Indexed: 02/03/2023] Open
Abstract
Background Bovine viral diarrhea virus (BVDV) infections continue to cause significantly losses in the deer population. Better isolation and identification of BVDV from sika deer may contribute significantly to the development of prophylactic therapeutic, and diagnostic reagents as well as help in prevention and control of BVDV. However, isolation and identification of BVDV from sika deer is seldom reported in literature. In this study, we collected some samples according to clinical sign of BVDV to isolation and identification of BVDV from sika deer. Results we isolated a suspected BVDV strain from livers of an aborted fetus from sika deer in Changchun (China) using MDBK cell lines, named as CCSYD strain, and identified it by cytopathic effect (CPE), indirect immunoperoxidase test (IPX) and electron microscopy(EM). The results indicated that this virus was BVDV by a series of identification. The structural proteins E0 gene was cloned and sequenced. The obtained E0 gene sequence has been submitted to GenBank with the accession number: FJ555203. Alignment with other 9 strains of BVDV, 7 strains of classical swine fever virus (CSFV) and 3 strains of border disease virus(BDV) in the world, showed that the homology were 98.6%-84.8%, 76.0%-74.7%, 76.6%-77.0% for nucleotide sequence, respectively. The phylogenetic analysis indicated that new isolation and identification CCSYD strain belonged to BVDV1b. Conclusion To the best of our knowledge, this is the first report that BVDV was isolated and identified in sika deer. This current research contributes development new BVDV vaccine to prevent and control of BVD in sika deer.
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Affiliation(s)
- Yugang Gao
- College of Traditional Material Medicine, Jinlin Agriculture University, Changchun, 130118, PR China
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43
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Yoshii K, Igarashi M, Ito K, Kariwa H, Holbrook MR, Takashima I. Construction of an infectious cDNA clone for Omsk hemorrhagic fever virus, and characterization of mutations in NS2A and NS5. Virus Res 2011; 155:61-8. [DOI: 10.1016/j.virusres.2010.08.023] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2010] [Revised: 08/26/2010] [Accepted: 08/26/2010] [Indexed: 10/19/2022]
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44
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Fan ZC, Bird RC. The extra 16-amino-acid peptide at C-terminal NS2 of the hypervirulent type-2 bovine viral diarrhea viruses has no effect on viral replication and NS2-3 processing of type-1 virus. Virus Genes 2010; 41:218-23. [DOI: 10.1007/s11262-010-0503-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2009] [Accepted: 06/11/2010] [Indexed: 11/24/2022]
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Pankraz A, Preis S, Thiel HJ, Gallei A, Becher P. A single point mutation in nonstructural protein NS2 of bovine viral diarrhea virus results in temperature-sensitive attenuation of viral cytopathogenicity. J Virol 2009; 83:12415-23. [PMID: 19776121 PMCID: PMC2786742 DOI: 10.1128/jvi.01487-09] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2009] [Accepted: 09/15/2009] [Indexed: 11/20/2022] Open
Abstract
For Bovine viral diarrhea virus (BVDV), the type species of the genus Pestivirus in the family Flaviviridae, cytopathogenic (cp) and noncytopathogenic (ncp) viruses are distinguished according to their effect on cultured cells. It has been established that cytopathogenicity of BVDV correlates with efficient production of viral nonstructural protein NS3 and with enhanced viral RNA synthesis. Here, we describe generation and characterization of a temperature-sensitive (ts) mutant of cp BVDV strain CP7, termed TS2.7. Infection of bovine cells with TS2.7 and the parent CP7 at 33 degrees C resulted in efficient viral replication and a cytopathic effect. In contrast, the ability of TS2.7 to cause cytopathogenicity at 39.5 degrees C was drastically reduced despite production of high titers of infectious virus. Further experiments, including nucleotide sequencing of the TS2.7 genome and reverse genetics, showed that a Y1338H substitution at residue 193 of NS2 resulted in the temperature-dependent attenuation of cytopathogenicity despite high levels of infectious virus production. Interestingly, TS2.7 and the reconstructed mutant CP7-Y1338H produced NS3 in addition to NS2-3 throughout infection. Compared to the parent CP7, NS2-3 processing was slightly decreased at both temperatures. Quantification of viral RNAs that were accumulated at 10 h postinfection demonstrated that attenuation of the cytopathogenicity of the ts mutants at 39.5 degrees C correlated with reduced amounts of viral RNA, while the efficiency of viral RNA synthesis at 33 degrees C was not affected. Taken together, the results of this study show that a mutation in BVDV NS2 attenuates viral RNA replication and suppresses viral cytopathogenicity at high temperature without altering NS3 expression and infectious virus production in a temperature-dependent manner.
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Affiliation(s)
- Alexander Pankraz
- Institute of Virology, Justus-Liebig University, D-35392 Giessen, Germany, Institute of Virology, Department of Infectious Diseases, University of Veterinary Medicine, D-30559 Hannover, Germany
| | - Simone Preis
- Institute of Virology, Justus-Liebig University, D-35392 Giessen, Germany, Institute of Virology, Department of Infectious Diseases, University of Veterinary Medicine, D-30559 Hannover, Germany
| | - Heinz-Jürgen Thiel
- Institute of Virology, Justus-Liebig University, D-35392 Giessen, Germany, Institute of Virology, Department of Infectious Diseases, University of Veterinary Medicine, D-30559 Hannover, Germany
| | - Andreas Gallei
- Institute of Virology, Justus-Liebig University, D-35392 Giessen, Germany, Institute of Virology, Department of Infectious Diseases, University of Veterinary Medicine, D-30559 Hannover, Germany
| | - Paul Becher
- Institute of Virology, Justus-Liebig University, D-35392 Giessen, Germany, Institute of Virology, Department of Infectious Diseases, University of Veterinary Medicine, D-30559 Hannover, Germany
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Weiskircher E, Aligo J, Ning G, Konan KV. Bovine viral diarrhea virus NS4B protein is an integral membrane protein associated with Golgi markers and rearranged host membranes. Virol J 2009; 6:185. [PMID: 19887001 PMCID: PMC2777160 DOI: 10.1186/1743-422x-6-185] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2009] [Accepted: 11/03/2009] [Indexed: 12/22/2022] Open
Abstract
Background Very little is known about BVDV NS4B, a protein of approximately 38 kDa. However, a missense mutation in NS4B has been implicated in changing BVDV from a cytopathic to noncytopathic virus, suggesting that NS4B might play a role in BVDV pathogenesis. Though this is one possible function, it is also likely that NS4B plays a role in BVDV genome replication. For example, BVDV NS4B interacts with NS3 and NS5A, implying that NS4B is part of a complex, which contains BVDV replicase proteins. Other possible BVDV NS4B functions can be inferred by analogy to hepatitis C virus (HCV) NS4B protein. For instance, HCV NS4B remodels host membranes to form the so-called membranous web, the site for HCV genome replication. Finally, HCV NS4B is membrane-associated, implying that HCV NS4B may anchor the virus replication complex to the membranous web structure. Unlike its HCV counterpart, we know little about the subcellular distribution of BVDV NS4B protein. Further, it is not clear whether NS4B is localized to host membrane alterations associated with BVDV infection. Results We show first that release of infectious BVDV correlates with the kinetics of BVDV genome replication in infected cells. Secondly, we found that NS4B subcellular distribution changes over the course of BVDV infection. Further, BVDV NS4B is an integral membrane protein, which colocalizes mainly with the Golgi compartment when expressed alone or in the context of BVDV infection. Additionally, BVDV induces host membrane rearrangement and these membranes contain BVDV NS4B protein. Finally, NS4B colocalizes with replicase proteins NS5A and NS5B proteins, raising the possibility that NS4B is a component of the BVDV replication complex. Interestingly, NS4B was found to colocalize with mitochondria suggesting that this organelle might play a role in BVDV genome replication or cytopathogenicity. Conclusion These results show that BVDV NS4B is an integral membrane protein associated with the Golgi apparatus and virus-induced membranes, the putative site for BVDV genome replication. On the basis of NS4B Colocalization with NS5A and NS5B, we conclude that NS4B protein is an integral component of the BVDV replication complex.
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Affiliation(s)
- Erica Weiskircher
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802, USA
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47
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Mischkale K, Reimann I, Zemke J, König P, Beer M. Characterisation of a new infectious full-length cDNA clone of BVDV genotype 2 and generation of virus mutants. Vet Microbiol 2009; 142:3-12. [PMID: 19875251 DOI: 10.1016/j.vetmic.2009.09.036] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Based on their genomic sequences, two genotypes of Bovine viral diarrhea virus (BVDV) can be differentiated, BVDV type 1 (BVDV-1) and BVDV type 2 (BVDV-2). The complete genomic sequence of the highly virulent BVDV-2 strain 890 was cloned as cDNA to establish the infectious cDNA clone p890FL. In vitro-synthesised full-length RNA of p890FL was transfected into bovine cells and infectious virus could be recovered (v890FL). In vitro, recombinant v890FL showed similar growth characteristics as wild type virus v890WT. However, infection experiments in calves revealed an attenuation of recombinant v890FL in comparison to the parental isolate. Both leukocytopenia and fever were less pronounced in v890FL-infected calves. Nevertheless, viremia and virus shedding were comparable between recombinant and parental BVDV 890. Furthermore, mutants with partial deletions of the genomic region encoding for the autoprotease N(pro) (p890DeltaN(pro)) or the capsid protein (p890DeltaC) were constructed and characterised. In order to generate pseudovirions, replicon p890DeltaC was efficiently trans-complemented on a helper cell line. In summary, the newly developed construct p890FL represents the first infectious full-length cDNA clone for the BVDV-2 strain 890 and offers a useful tool for further studies on the pathogenesis of BVDV-2 and the development of novel recombinant BVDV-2 specific vaccine candidates.
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Affiliation(s)
- Katrin Mischkale
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Südufer 10, D-17493 Greifswald-Insel Riems, Germany
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Okamoto M, Sakai M, Goto Y, Salim MTA, Baba C, Goto K, Watashi K, Shimotohno K, Baba M. Anti-bovine viral diarrhoea virus and hepatitis C virus activity of the cyclooxygenase inhibitor SC-560. Antivir Chem Chemother 2009; 20:47-54. [PMID: 19794231 DOI: 10.3851/imp1372] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND A number of compounds were examined for their inhibitory effect on bovine viral diarrhoea virus (BVDV) replication in cell cultures and found that some cyclooxygenase (COX) inhibitors had antiviral activity against the virus. METHODS Determination of compounds for their anti-BVDV activity was on the basis of the inhibition of virus-induced cytopathogenicity in Mardin-Darby bovine kidney (MDBK) cells. Anti-hepatitis C virus (HCV) activity was assessed by the inhibition of viral RNA synthesis in the subgenomic HCV RNA replicon cells. RESULTS Among the test compounds, 5-(4-chlorophenyl)-1-(4-methoxyphenyl)-3-(trifluoromethyl)-1H-pyrazole (SC-560) was the most active against BVDV, and its 50% effective and cytotoxic concentrations were 10.9 +/-2.8 and 93.9 +/-24.5 microM in virus and mock-infected MDBK cells, respectively. The compound also suppressed BVDV RNA synthesis in a dose-dependent fashion. Studies on the mechanism of action revealed that SC-560 did not interfere with viral entry to the host cells. Furthermore, it was assumed that the antiviral activity of SC-560 was not associated with its inhibitory effect on COX. The combination of SC-560 and interferon-alpha was additive to synergistic in inhibiting BVDV replication. More importantly, the compound proved to be a selective inhibitor of HCV replication. CONCLUSIONS SC-560 and its derivative might have potential as novel antiviral agents against HCV.
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Affiliation(s)
- Mika Okamoto
- Division of Antiviral Chemotherapy, Center for Chronic Viral Diseases, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan
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49
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Mätzener P, Magkouras I, Rümenapf T, Peterhans E, Schweizer M. The viral RNase E(rns) prevents IFN type-I triggering by pestiviral single- and double-stranded RNAs. Virus Res 2008; 140:15-23. [PMID: 19041350 DOI: 10.1016/j.virusres.2008.10.015] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2008] [Revised: 10/27/2008] [Accepted: 10/28/2008] [Indexed: 12/25/2022]
Abstract
Interferon (IFN) type-I is of utmost importance in the innate antiviral defence of eukaryotic cells. The cells express intra- and extracellular receptors that monitor their surroundings for the presence of viral genomes. Bovine viral diarrhoea virus (BVDV), a Pestivirus of the family Flaviviridae, is able to prevent IFN synthesis induced by poly(IC), a synthetic dsRNA. The evasion of innate immunity might be a decisive ability of BVDV to establish persistent infection in its host. We report that ds- as well as ssRNA fragments of viral origin are able to trigger IFN synthesis, and that the viral envelope glycoprotein E(rns), that is also secreted from infected cells, is able to inhibit IFN expression induced by these extracellular viral RNAs. The RNase activity of E(rns) is required for this inhibition, and E(rns) degrades ds- and ssRNA at neutral pH. In addition, cells infected with a cytopathogenic strain of BVDV contain more dsRNA than cells infected with the homologous non-cytopathogenic strain, and the intracellular viral RNA was able to excite the IFN system in a 5'-triphosphate-, i.e. RIG-I-, independent manner. Functionally, E(rns) might represent a decoy receptor that binds and enzymatically degrades viral RNA that otherwise might activate the IFN defence by binding to Toll-like receptors of uninfected cells. Thus, the pestiviral RNase efficiently manipulates the host's self-nonself discrimination to successfully establish and maintain persistence and immunotolerance.
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Affiliation(s)
- Philippe Mätzener
- Institute of Veterinary Virology, University of Bern, Laenggass-Str. 122, P.O. Box 8466, CH-3001 Bern, Switzerland
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Regeneration and characterization of a recombinant bovine viral diarrhea virus and determination of its efficacy to cross the bovine placenta. Virus Genes 2008; 38:129-35. [PMID: 19067148 DOI: 10.1007/s11262-008-0308-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2008] [Accepted: 11/17/2008] [Indexed: 10/21/2022]
Abstract
The capacity of different bovine viral diarrhea virus (BVDV) strains to cause transplacental infection is variable. BVDV strain SD-1 was isolated from a persistently infected heifer. Its genome represents the only reported nucleotide sequence of a noncytopathic viral isolate determined without cell culture passage in the laboratory. Thus, SD-1 might possess biological advantages over other NCP BVDV strains to be used as a model virus for investigation of viral transplacental transmission. To evaluate if a molecularly generated BVDV SD-1 is capable of crossing the bovine placenta efficiently, a full-length cDNA clone of SD-1 was constructed using RT-PCR amplification and standard molecular techniques. In vitro transcripts synthesized from the cDNA template directed the generation of infectious virus in MDBK cells with a transfection efficiency as high as 4.7 x 10(5) FFU/mug RNA. The recovered virus termed ASD1 harbored five silent point mutations engineered as genetic markers and was similar to wild type (wt) SD-1 in viral growth kinetics. As evaluated in the pregnant heifers, ASD1 was capable of crossing the bovine placenta efficiently, suggesting that NCP BVDV SD-1 is a suitable viral backbone for investigation of the role of viral genetic element(s) in viral transplacental transmission by allowing for evaluation of newly created viral mutants.
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