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Characterization of Pseudorabies Virus Associated with Severe Respiratory and Neuronal Signs in Old Pigs. Transbound Emerg Dis 2023. [DOI: 10.1155/2023/8855739] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/04/2023]
Abstract
Pseudorabies virus (PRV) represents a leading threat to the global pig industry. Generally, pigs exhibit a pronounced age resistance against PRV, and the virus generally does not cause severe clinical signs and even death in old pigs. However, we characterized two PRV strains (HeN21 and HuB20) associated with severe respiratory and neuronal signs in old pigs. Among these two strains, HeN21 was isolated from the tonsil of a 24-week-old pig that died from severe neuronal and respiratory signs in a PRV-outbreak farm where a commercial PRV attenuated vaccine developed based on a PRV variant was used; while, HuB20 was isolated from the lung and lymph node of a 20-week-old with symptoms in another farm where Bartha-K61 vaccine was used. In vitro evaluations in different cell models demonstrated that HeN21 and HuB20 led to similar cytotoxic effects to those caused by PRV variants on PK-15, Vero, and SK-N-SH cells after 30 hours of inoculation. However, HeN21 possessed a higher titer than the other PRV variants from the first to the fifth passage on PK-15 cells and induced plaques with larger size. In vivo assessments in mouse and fattening pig models showed that inoculations of HeN21 and HuB20 caused higher morbidity and mortality and severe pathological damages in tested animals. In particular, challenge of HeN21 led to severe respiratory and neuronal signs in 90-day-old pigs. These two strains displayed higher virus loads on the main organs of challenged mice and pigs. Phylogenetic analysis revealed that HeN21 and HuB20 belonged to genotype II. In addition, recombinant events were identified in the genomes of HeN21 and HuB20, and several events were located within genes associated with PRV virulence. Our data herein may suggest the emergence of novel PRV strains in China.
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Ariza ME, Cox B, Martinez B, Mena-Palomo I, Zarate GJ, Williams MV. Viral dUTPases: Modulators of Innate Immunity. Biomolecules 2022; 12:227. [PMID: 35204728 PMCID: PMC8961515 DOI: 10.3390/biom12020227] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Revised: 01/24/2022] [Accepted: 01/26/2022] [Indexed: 11/17/2022] Open
Abstract
Most free-living organisms encode for a deoxyuridine triphosphate nucleotidohydrolase (dUTPase; EC 3.6.1.23). dUTPases represent a family of metalloenzymes that catalyze the hydrolysis of dUTP to dUMP and pyrophosphate, preventing dUTP from being incorporated into DNA by DNA polymerases, maintaining a low dUTP/dTTP pool ratio and providing a necessary precursor for dTTP biosynthesis. Thus, dUTPases are involved in maintaining genomic integrity by preventing the uracilation of DNA. Many DNA-containing viruses, which infect mammals also encode for a dUTPase. This review will summarize studies demonstrating that, in addition to their classical enzymatic activity, some dUTPases possess novel functions that modulate the host innate immune response.
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Affiliation(s)
- Maria Eugenia Ariza
- Department of Cancer Biology and Genetics, The Ohio State University Wexner Medical Center, Columbus, OH 43210, USA;
- Institute for Behavioral Medicine Research, The Ohio State University Wexner Medical Center, Columbus, OH 43210, USA; (B.C.); (B.M.); (I.M.-P.); (G.J.Z.)
| | - Brandon Cox
- Institute for Behavioral Medicine Research, The Ohio State University Wexner Medical Center, Columbus, OH 43210, USA; (B.C.); (B.M.); (I.M.-P.); (G.J.Z.)
| | - Britney Martinez
- Institute for Behavioral Medicine Research, The Ohio State University Wexner Medical Center, Columbus, OH 43210, USA; (B.C.); (B.M.); (I.M.-P.); (G.J.Z.)
| | - Irene Mena-Palomo
- Institute for Behavioral Medicine Research, The Ohio State University Wexner Medical Center, Columbus, OH 43210, USA; (B.C.); (B.M.); (I.M.-P.); (G.J.Z.)
| | - Gloria Jeronimo Zarate
- Institute for Behavioral Medicine Research, The Ohio State University Wexner Medical Center, Columbus, OH 43210, USA; (B.C.); (B.M.); (I.M.-P.); (G.J.Z.)
| | - Marshall Vance Williams
- Department of Cancer Biology and Genetics, The Ohio State University Wexner Medical Center, Columbus, OH 43210, USA;
- Institute for Behavioral Medicine Research, The Ohio State University Wexner Medical Center, Columbus, OH 43210, USA; (B.C.); (B.M.); (I.M.-P.); (G.J.Z.)
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Li W, Zhuang D, Li H, Zhao M, Zhu E, Xie B, Chen J, Zhao M. Recombinant pseudorabies virus with gI/gE deletion generated by overlapping polymerase chain reaction and homologous recombination technology induces protection against the PRV variant PRV-GD2013. BMC Vet Res 2021; 17:164. [PMID: 33853597 PMCID: PMC8048318 DOI: 10.1186/s12917-021-02861-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Accepted: 03/27/2021] [Indexed: 01/30/2023] Open
Abstract
BACKGROUND Since 2011, numerous highly virulent and antigenic variant viral strains have been reported in pigs that were vaccinated against the swine pseudorabies virus. These infections have led to substantial economic losses in the Chinese swine industry. RESULTS This study, constructed a novel recombinant vaccine strain with gI/gE deletion (PRV-GD2013-ΔgI/gE) by overlapping PCR and homologous recombination technology. The growth curves and plaque morphology of the recombinant virus were similar to those of the parental strain. However, PRV-GD2013-ΔgI/gE infection was significantly attenuated in mice compared with that of PRV-GD2013. Two-week-old piglets had normal rectal temperatures and displayed no clinical symptoms after being inoculated with 105 TCID50 PRV-GD2013-ΔgI/gE, indicating that the recombinant virus was avirulent in piglets. Piglets were immunized with different doses of PRV-GD2013-ΔgI/gE, or a single dose of Bartha-K61 or DMEM, and infected with PRV-GD2013 at 14 days post-vaccination. Piglets given high doses of PRV-GD2013-ΔgI/gE showed no obvious clinical symptoms, and their antibody levels were higher than those of other groups, indicating that the piglets were completely protected from PRV-GD2013. CONCLUSIONS The PRV-GD2013-ΔgI/gE vaccine strain could be effective for immunizing Chinese swine herds against the pseudorabies virus (PRV) strain.
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Affiliation(s)
- Wenhui Li
- College of Veterinary Medicine, South China Agricultural University, 483 Wu Shan Road, Tianhe District, Guangzhou, 510642, Guangdong Province, China
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, China
| | - Dijing Zhuang
- College of Veterinary Medicine, South China Agricultural University, 483 Wu Shan Road, Tianhe District, Guangzhou, 510642, Guangdong Province, China
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, China
| | - Hong Li
- Shandong Qianxi Agriculture & Animal Husbandry Development Co., Ltd., Zaozhuang, China
| | - Mengpo Zhao
- College of Veterinary Medicine, South China Agricultural University, 483 Wu Shan Road, Tianhe District, Guangzhou, 510642, Guangdong Province, China
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, China
| | - Erpeng Zhu
- College of Veterinary Medicine, South China Agricultural University, 483 Wu Shan Road, Tianhe District, Guangzhou, 510642, Guangdong Province, China
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, China
| | - Baoming Xie
- College of Veterinary Medicine, South China Agricultural University, 483 Wu Shan Road, Tianhe District, Guangzhou, 510642, Guangdong Province, China
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, China
| | - Jinding Chen
- College of Veterinary Medicine, South China Agricultural University, 483 Wu Shan Road, Tianhe District, Guangzhou, 510642, Guangdong Province, China
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, China
| | - Mingqiu Zhao
- College of Veterinary Medicine, South China Agricultural University, 483 Wu Shan Road, Tianhe District, Guangzhou, 510642, Guangdong Province, China.
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, China.
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Schröder L, Klafack S, Bergmann SM, Fichtner D, Jin Y, Lee PY, Höper D, Mettenleiter TC, Fuchs W. Generation of a potential koi herpesvirus live vaccine by simultaneous deletion of the viral thymidine kinase and dUTPase genes. J Gen Virol 2018; 100:642-655. [PMID: 30230443 DOI: 10.1099/jgv.0.001148] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Koi herpesvirus (KHV, Cyprinidherpesvirus 3) causes a fatal disease of koi and common carp. To obtain safe and efficacious live vaccines, we generated deletion mutants of KHV lacking the nonessential genes encoding two enzymes of nucleotide metabolism, thymidine kinase (TK, ORF55) and deoxyuridine-triphosphatase (DUT, ORF123). Since single-deletion mutants based on a KHV isolate from Israel (KHV-I) only exhibited partial attenuation (Fuchs W, Fichtner D, Bergmann SM, Mettenleiter TC. Arch Virol 2011;156 : 1059-1063), a corresponding double mutant was generated and tested in vivo, and shown to be almost avirulent but still protective. To overcome the low in vitro virus titres of KHV-I (≤105 p.f.u. ml-1), single and double TK and DUT deletions were also introduced into a cell culture-adapted KHV strain from Taiwan (KHV-T). The deletions did not affect in vitro virus replication, and all KHV-T mutants exhibited wild-type-like plaque sizes and titres exceeding 107 p.f.u. ml-1, as a prerequisite for economic vaccine production. Compared to wild-type and revertant viruses, the single-deletion mutants of KHV-T were significantly attenuated in vivo, and immersion of juvenile carp in water containing high doses of the double mutant caused almost no fatalities. Nevertheless, the deletion mutants induced similar levels of KHV-specific serum antibodies to the parental wild-type virus, and conferred solid protection against disease after challenge with wild-type KHV. For the convenient differentiation of DNA samples prepared from gill swabs of carp infected with wild-type and TK-deleted KHV we developed a triplex real-time PCR. Thus, KHV-TΔDUT/TK might be suitable as a genetic DIVA vaccine in the field.
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Affiliation(s)
- Lars Schröder
- 1Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Greifswald-Insel Riems, Germany
| | - Sandro Klafack
- 2Institute of Infectology, Friedrich-Loeffler-Institut, Greifswald-Insel Riems, Germany
| | - Sven M Bergmann
- 2Institute of Infectology, Friedrich-Loeffler-Institut, Greifswald-Insel Riems, Germany
| | - Dieter Fichtner
- 2Institute of Infectology, Friedrich-Loeffler-Institut, Greifswald-Insel Riems, Germany
| | - Yeonhwa Jin
- 2Institute of Infectology, Friedrich-Loeffler-Institut, Greifswald-Insel Riems, Germany
| | - Pei-Yu Lee
- 3GeneReach Biotechnology Corporation, Taichung, Taiwan, ROC
| | - Dirk Höper
- 4Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Greifswald-Insel Riems, Germany
| | - Thomas C Mettenleiter
- 1Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Greifswald-Insel Riems, Germany
| | - Walter Fuchs
- 1Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Greifswald-Insel Riems, Germany
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Murine cytomegalovirus M72 promotes acute virus replication in vivo and is a substrate of the TRiC/CCT complex. Virology 2018; 522:92-105. [PMID: 30029015 DOI: 10.1016/j.virol.2018.07.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Revised: 07/05/2018] [Accepted: 07/07/2018] [Indexed: 01/30/2023]
Abstract
Betaherpesvirus dUTPase homologs are core herpesvirus proteins, but little is known about their role during infection. Human cytomegalovirus (HCMV) UL72 and murine cytomegalovirus (MCMV) M72 have been designated dUTPase homologs, and previous studies indicate UL72 is dispensable for replication and enzymatically inactive. Here, we report the initial characterization of MCMV M72. M72 does not possess dUTPase activity, and is expressed as a leaky-late gene product with multiple protein isoforms. Importantly, M72 augments MCMV replication in vitro and during the early stage of acute infection in vivo. We identify and confirm interaction of M72 with the eukaryotic chaperonin tailless complex protein -1 (TCP-1) ring complex (TRiC) or chaperonin containing tailless complex polypeptide 1 (CCT). Accumulating biochemical evidence indicates M72 forms homo-oligomers and is a substrate of TRiC/CCT. Taken together, we provide the first evidence of M72's contribution to viral pathogenesis, and identify a novel interaction with the TRiC/CCT complex.
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Fuchs W, Fichtner D, Bergmann SM, Mettenleiter TC. Generation and characterization of koi herpesvirus recombinants lacking viral enzymes of nucleotide metabolism. Arch Virol 2011; 156:1059-63. [PMID: 21387205 DOI: 10.1007/s00705-011-0953-8] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2010] [Accepted: 02/10/2011] [Indexed: 12/01/2022]
Abstract
Koi herpesvirus (KHV) causes a fatal disease in koi and common carp, but no reliable and genetically characterized vaccines are available up to now. Therefore, we generated KHV recombinants possessing deletions within the viral ribonucleotide reductase (RNR), thymidine kinase (TK), dUTPase, or TK and dUTPase genes, and their corresponding rescuants. All KHV mutants were replication competent in cultured cells. Whereas plaque sizes and titers of RNR-negative KHV were reduced, replication of the other mutants was not affected. Experimental infection of carp indicated attenuation of TK- or dUTPase-deleted KHV, and PCR analysis of tissue samples permitted differentiation of mutant from wild-type virus.
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Affiliation(s)
- Walter Fuchs
- Institute of Molecular Biology, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, 17493 Greifswald-Insel Riems, Germany.
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Tóth JS, Tombácz D, Takács IF, Boldogkoi Z. The effects of viral load on pseudorabies virus gene expression. BMC Microbiol 2010; 10:311. [PMID: 21134263 PMCID: PMC3016322 DOI: 10.1186/1471-2180-10-311] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2010] [Accepted: 12/06/2010] [Indexed: 05/08/2023] Open
Abstract
Background Herpesvirus genes are classified into distinct kinetic groups on the basis of their expression dynamics during lytic growth of the virus in cultured cells at a high, typically 10 plaque-forming units/cell multiplicity of infection (MOI). It has been shown that both the host response and the success of a pathogen are dependent on the quantity of particles infecting an organism. This work is a continuation of an earlier study [1], in which we characterized the overall expression of PRV genes following low-MOI infection. In the present study, we have addressed the question of whether viral gene expressions are dependent on the multiplicity of infection by comparing gene expressions under low and high-MOI conditions. Results In the present study, using a real-time RT-PCR assay, we address the question of whether the expression properties of the pseudorabies virus (PRV) genes are dependent on the number of virion particles infecting a single cell in a culture. Our analysis revealed a significant dependence of the gene expression on the MOI in most of these genes. Specifically, we found that most of the examined viral genes were expressed at a lower level at a low MOI (0.1) than at a high MOI (10) experiment in the early stage of infection; however, this trend reversed by six hour post-infection in more than half of the genes. Furthermore, in the high-MOI infection, several PRV genes substantially declined within the 4 to 6-h infection period, which was not the case in the low-MOI infection. In the low-MOI infection, the level of antisense transcript (AST), transcribed from the antiparallel DNA strand of the immediate-early 180 (ie180) gene, was comparable to that of ie180 mRNA, while in the high-MOI experiment (despite the 10 times higher copy number of the viral genome in the infected cells) the amount of AST dropped by more than two log values at the early phase of infection. Furthermore, our analysis suggests that adjacent PRV genes are under a common regulation. This is the first report on the effect of the multiplicity of infection on genome-wide gene expression of large DNA viruses, including herpesviruses. Conclusion Our results show a strong dependence of the global expression of PRV genes on the MOI. Furthermore, our data indicate a strong interrelation between the expressions of ie180 mRNA and AST, which determines the expression properties of the herpesvirus genome and possibly the replication strategy (lytic or latent infection) of the virus in certain cell types.
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Affiliation(s)
- Judit S Tóth
- Department of Medical Biology, Faculty of Medicine, University of Szeged, Hungary
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Ward TM, Williams MV, Traina-Dorge V, Gray WL. The simian varicella virus uracil DNA glycosylase and dUTPase genes are expressed in vivo, but are non-essential for replication in cell culture. Virus Res 2009; 142:78-84. [PMID: 19200445 DOI: 10.1016/j.virusres.2009.01.013] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2008] [Revised: 01/15/2009] [Accepted: 01/15/2009] [Indexed: 10/21/2022]
Abstract
Neurotropic herpesviruses express viral deoxyuridine triphosphate nucleotidohydrolase (dUTPase) and uracil DNA glycosylase (UDG) enzymes which may reduce uracil misincorporation into viral DNA, particularly in neurons of infected ganglia. The simian varicella virus (SVV) dUTPase (ORF 8) and UDG (ORF 59) share 37.7% and 53.9% amino acid identity, respectively, with varicella-zoster virus (VZV) homologs. Infectious SVV mutants defective in either dUTPase (SVV-dUTPase(-)) or UDG (SVV-UDG(-)) activity or both (SVV-dUTPase(-)/UDG(-)) were constructed using recA assisted restriction endonuclease cleavage (RARE) and a cosmid recombination system. Loss of viral dUTPase and UDG enzymatic activity was confirmed in CV-1 cells infected with the SVV mutants. The SVV-dUTPase(-), SVV-UDG(-), and SVV-dUTPase(-)/UDG(-) mutants replicated as efficiently as wild-type SVV in cell culture. SVV dUTPase and UDG expression was detected in tissues derived from acutely infected animals, but not in tissues derived from latently infected animals. Further studies will evaluate the pathogenesis of SVV dUTPase and UDG mutants and their potential as varicella vaccines.
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Affiliation(s)
- Toby M Ward
- Department of Microbiology and Immunology, 4301 West Markham Street, University of Arkansas for Medical Sciences, Slot 511, Little Rock, AR 72205, United States
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Spatz SJ, Petherbridge L, Zhao Y, Nair V. Comparative full-length sequence analysis of oncogenic and vaccine (Rispens) strains of Marek's disease virus. J Gen Virol 2007; 88:1080-1096. [PMID: 17374751 DOI: 10.1099/vir.0.82600-0] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
The complete DNA sequence of the Marek's disease virus serotype 1 vaccine strain CVI988 was determined and consists of 178 311 bp with an overall gene organization identical to that of the oncogenic strains. In examining open reading frames (ORFs), nine differ between vaccine and oncogenic strains. A 177 bp insertion was identified in the overlapping genes encoding the Meq, RLORF6 and 23 kDa proteins of CVI988. Three ORFs are predicted to encode truncated proteins. One, designated 49.1, overlaps the gene encoding the large tegument protein UL36 and encodes a severely truncated protein of 34 aa. The others, ORF5.5/ORF75.91 and ORF3.0/78.0, located in the repeat regions (diploid), encode a previously unidentified ORF of 52 aa and a truncated version of the virus-encoded chemokine (vIL-8), respectively. Subtle genetic changes were identified in the two ORFs encoding tegument proteins UL36 and UL49. Only one diploid ORF (ORF6.2/ORF75.6) present in the genomes of the three virulent strains is absent in the CVI988-BAC genome. Seventy non-synonymous amino acid substitutions were identified that could differentiate CVI988-BAC from all three oncogenic strains collectively. Estimates of the non-synonymous to synonymous substitution ratio (ω) indicate that CVI988 ORFs are generally under purifying selection (ω<1), whereas UL39, UL49, UL50, RLORF6 and RLORF7 (Meq) appear to evolve under relaxed selective constraints. No CVI988 ORF was found to be under positive evolutionary selection (ω≫1).
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Affiliation(s)
- Stephen J Spatz
- Southeast Poultry Research Laboratory, Agricultural Research Service, United States Department of Agriculture, Athens, GA 30605, USA
| | | | - Yuguang Zhao
- Institute for Animal Health, Compton, Berkshire RG20 7NN, UK
| | - Venugopal Nair
- Institute for Animal Health, Compton, Berkshire RG20 7NN, UK
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10
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Nauwynck H, Glorieux S, Favoreel H, Pensaert M. Cell biological and molecular characteristics of pseudorabies virus infections in cell cultures and in pigs with emphasis on the respiratory tract. Vet Res 2007; 38:229-41. [PMID: 17257571 DOI: 10.1051/vetres:200661] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2006] [Accepted: 11/23/2006] [Indexed: 11/14/2022] Open
Abstract
In the present review, several cell biological and molecular aspects of virus-cell and virus-host (pig) interactions are reviewed for pseudorabies (Aujeszky's disease) virus. Concerning the virus-cell interactions, the complex cascade of events in the virus replication cycle is given together with the different mechanisms of cell-to-cell spread. The pathogenesis of pseudorabies virus infections in pigs is concentrated on the sequence of events in the respiratory tract. Finally, a short overview is given on the control of the disease and eradication of the virus by the combination of marker vaccines and discriminating ELISA.
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Affiliation(s)
- Hans Nauwynck
- Laboratory of Virology, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium.
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Pomeranz LE, Reynolds AE, Hengartner CJ. Molecular biology of pseudorabies virus: impact on neurovirology and veterinary medicine. Microbiol Mol Biol Rev 2005; 69:462-500. [PMID: 16148307 PMCID: PMC1197806 DOI: 10.1128/mmbr.69.3.462-500.2005] [Citation(s) in RCA: 580] [Impact Index Per Article: 30.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Pseudorabies virus (PRV) is a herpesvirus of swine, a member of the Alphaherpesvirinae subfamily, and the etiological agent of Aujeszky's disease. This review describes the contributions of PRV research to herpesvirus biology, neurobiology, and viral pathogenesis by focusing on (i) the molecular biology of PRV, (ii) model systems to study PRV pathogenesis and neurovirulence, (iii) PRV transsynaptic tracing of neuronal circuits, and (iv) veterinary aspects of pseudorabies disease. The structure of the enveloped infectious particle, the content of the viral DNA genome, and a step-by-step overview of the viral replication cycle are presented. PRV infection is initiated by binding to cellular receptors to allow penetration into the cell. After reaching the nucleus, the viral genome directs a regulated gene expression cascade that culminates with viral DNA replication and production of new virion constituents. Finally, progeny virions self-assemble and exit the host cells. Animal models and neuronal culture systems developed for the study of PRV pathogenesis and neurovirulence are discussed. PRV serves asa self-perpetuating transsynaptic tracer of neuronal circuitry, and we detail the original studies of PRV circuitry mapping, the biology underlying this application, and the development of the next generation of tracer viruses. The basic veterinary aspects of pseudorabies management and disease in swine are discussed. PRV infection progresses from acute infection of the respiratory epithelium to latent infection in the peripheral nervous system. Sporadic reactivation from latency can transmit PRV to new hosts. The successful management of PRV disease has relied on vaccination, prevention, and testing.
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Affiliation(s)
- Lisa E Pomeranz
- Department of Molecular Biology, Princeton University, Princeton, New Jersey 08540, USA.
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12
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Zhang Y, Moriyama H, Homma K, Van Etten JL. Chlorella virus-encoded deoxyuridine triphosphatases exhibit different temperature optima. J Virol 2005; 79:9945-53. [PMID: 16014955 PMCID: PMC1181562 DOI: 10.1128/jvi.79.15.9945-9953.2005] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A putative deoxyuridine triphosphatase (dUTPase) gene from chlorella virus PBCV-1 was cloned, and the recombinant protein was expressed in Escherichia coli. The recombinant protein has dUTPase activity and requires Mg(2+) for optimal activity, while it retains some activity in the presence of other divalent cations. Kinetic studies of the enzyme revealed a K(m) of 11.7 microM, a turnover k(cat) of 6.8 s(-1), and a catalytic efficiency of k(cat)/K(m) = 5.8 x 10(5) M(-1) s(-1). dUTPase genes were cloned and expressed from two other chlorella viruses IL-3A and SH-6A. The two dUTPases have similar properties to PBCV-1 dUTPase except that IL-3A dUTPase has a lower temperature optimum (37 degrees C) than PBCV-1 dUTPase (50 degrees C). The IL-3A dUTPase differs from the PBCV-1 enzyme by nine amino acids, including two amino acid substitutions, Glu81-->Ser81 and Thr84-->Arg84, in the highly conserved motif III of the proteins. To investigate the difference in temperature optima between the two enzymes, homology modeling and docking simulations were conducted. The results of the simulation and comparisons of amino acid sequence suggest that adjacent amino acids are important in the temperature optima. To confirm this suggestion, three site-directed amino acid substitutions were made in the IL-3A enzyme: Thr84-->Arg84, Glu81-->Ser81, and Glu81-->Ser81 plus Thr84-->Arg84. The single substitutions affected the optimal temperature for enzyme activity. The temperature optimum increased from 37 to 55 degrees C for the enzyme containing the two amino acid substitutions. We postulate that the change in temperature optimum is due to reduction in charge and balkiness in the active cavity that allows more movement of the ligand and protein before the enzyme and substrate complex is formed.
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Affiliation(s)
- Yuanzheng Zhang
- Department of Plant Pathology, University of Nebraska-Lincoln, 68583-0722, USA
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13
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Cottone R, Büttner M, McInnes CJ, Wood AR, Rziha HJ. Orf virus encodes a functional dUTPase gene. J Gen Virol 2002; 83:1043-1048. [PMID: 11961258 DOI: 10.1099/0022-1317-83-5-1043] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The present study is the first report on the functional activity of a parapoxvirus-encoded dUTPase. The dUTPase gene of the attenuated orf virus (ORFV), strain D1701, was expressed as a bacterial thioredoxin fusion protein. In vitro assays showed that ORFV dUTPase was highly specific for dUTP as substrate. The enzyme was active over a broad pH range (pH 6.0-9.0), with maximal enzymatic activity at pH 7.0 in the presence of Mg(2+) cations. Kinetic studies of the recombinant ORFV dUTPase revealed an apparent K(m) of 4.0 microM, which is more similar to that of the mammalian or African swine fever virus enzyme than to the K(m) of vaccinia virus dUTPase. Enzyme activity was also found with purified ORFV particles, indicating its virion association.
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Affiliation(s)
- R Cottone
- Federal Research Centre for Virus Diseases of Animals, Institute for Immunology, Paul-Ehrlich-Straße 28, D-72076 Tübingen, Federal Republic of Germany1
| | - M Büttner
- Federal Research Centre for Virus Diseases of Animals, Institute for Immunology, Paul-Ehrlich-Straße 28, D-72076 Tübingen, Federal Republic of Germany1
| | - C J McInnes
- Moredun Research Institute, International Research Centre, Pentlands Science Park, Penicuik, Midlothian EH26 OPZ, UK2
| | - A R Wood
- Moredun Research Institute, International Research Centre, Pentlands Science Park, Penicuik, Midlothian EH26 OPZ, UK2
| | - H-J Rziha
- Federal Research Centre for Virus Diseases of Animals, Institute for Immunology, Paul-Ehrlich-Straße 28, D-72076 Tübingen, Federal Republic of Germany1
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14
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Lüschow D, Werner O, Mettenleiter TC, Fuchs W. Protection of chickens from lethal avian influenza A virus infection by live-virus vaccination with infectious laryngotracheitis virus recombinants expressing the hemagglutinin (H5) gene. Vaccine 2001; 19:4249-59. [PMID: 11457552 DOI: 10.1016/s0264-410x(01)00167-0] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
The H5 hemagglutinin (HA) gene of a highly pathogenic avian influenza virus (AIV) isolate (A/chicken/Italy/8/98) was cloned and sequenced, and inserted at the non-essential UL50 (dUTPase) gene locus of a virulent strain of infectious laryngotracheitis virus (ILTV). Northern and Western blot analyses of the obtained ILTV recombinants demonstrated stable expression of the HA gene under control of the human cytomegalovirus immediate-early gene promoter. In vitro replication of the HA-expressing ILTV mutants was not affected, and infection of chickens revealed a reduced but still considerable virulence, similar to that of a UL50 gene deletion mutant without foreign gene insertion. The immunized animals produced specific antibodies against ILTV and AIV HA, and were protected against challenge infections with either virulent ILTV, or two different highly pathogenic AIV strains (A/chicken/Italy/8/98, A/chicken/Scotland/59). After challenge, no ILTV could be reisolated from protected animals, and shedding of AIV was considerably reduced. Thus, although attenuation remains to be improved, genetically engineered ILTV live-virus vaccines might be used as vectors to protect chickens also against other pathogens.
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Affiliation(s)
- D Lüschow
- Institute of Molecular Biology, Friedrich-Loeffler-Institutes, Federal Research Centre for Virus Diseases of Animals, D-17498, Insel Riems, Germany
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15
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Nord J, Nyman P, Larsson G, Drakenberg T. The C-terminus of dUTPase: observation on flexibility using NMR. FEBS Lett 2001; 492:228-32. [PMID: 11257499 DOI: 10.1016/s0014-5793(01)02257-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The dynamics of the C-terminus of the dUTPases from Escherichia coli and equine infectious anaemia virus (EIAV) were studied by 1H-(15)N nuclear magnetic resonance spectroscopy. The two enzymes differ with regard to flexibility in the backbone of the 15 most C-terminal amino acid residues, some of which are conserved and essential for enzymic activity. In the bacterial enzyme, the residues closest to the C-terminus are highly flexible and display a correlation time in the nanosecond time range. No similar high flexibility could be detected for the C-terminal part of EIAV dUTPase, indicating a different time range of flexibility.
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Affiliation(s)
- J Nord
- Department of Biochemistry, Center for Chemistry and Chemical Engineering, Lund University, Sweden. johan.nord@astrazeneca
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16
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Nord J, Kiefer M, Adolph HW, Zeppezauer MM, Nyman PO. Transient kinetics of ligand binding and role of the C-terminus in the dUTPase from equine infectious anemia virus. FEBS Lett 2000; 472:312-6. [PMID: 10788633 DOI: 10.1016/s0014-5793(00)01453-8] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Transient kinetics of the equine infectious anemia virus deoxyuridine 5'-triphosphate nucleotide hydrolase were characterized by monitoring the fluorescence of the protein. Rate constants for the association and dissociation of substrate and inhibitors were determined and found to be consistent with a one-step mechanism for substrate binding. A C-terminal part of the enzyme presumed to be flexible was removed by limited trypsinolysis. As a result, the activity of the dUTPase was completely quenched, but the rate constants and fluorescent signal of the truncated enzyme were affected only to a minor degree. We conclude that the flexible C-terminus is not a prerequisite for substrate binding, but indispensable for catalysis.
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Affiliation(s)
- J Nord
- Department of Biochemistry, Center for Chemistry and Chemical Engineering, University of Lund, P.O. Box 124, S-221 00, Lund, Sweden.
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17
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Fuchs W, Ziemann K, Teifke JP, Werner O, Mettenleiter TC. The non-essential UL50 gene of avian infectious laryngotracheitis virus encodes a functional dUTPase which is not a virulence factor. J Gen Virol 2000; 81:627-38. [PMID: 10675400 DOI: 10.1099/0022-1317-81-3-627] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The DNA sequence of the infectious laryngotracheitis virus (ILTV) UL50, UL51 and UL52 gene homologues was determined. Although the deduced UL50 protein lacks the first of five conserved domains of the corresponding proteins of mammalian alphaherpesviruses, the ILTV gene product was also shown to possess dUTPase activity. The generation of UL50-negative ILTV mutants was facilitated by recombination plasmids encoding green fluorescent protein (GFP), and expression constructs of predicted transactivator proteins of ILTV (alphaTIF, ICP4) were successfully used to increase the infectivity of viral genomic DNA. A GFP-expressing UL50-deletion mutant of ILTV showed reduced cell-to-cell spread in vitro, and was attenuated in vivo. A similar deletion mutant without the foreign gene, however, propagated like wild-type ILTV in cell culture and was pathogenic in chickens. We conclude that the viral dUTPase is not required for efficient replication of ILTV in the respiratory tract of infected animals. The replication defect of the GFP-expressing ILTV recombinant is most likely caused by toxic effects of the reporter gene product, since spontaneously occurring inactivation mutants exhibited wild-type-like growth.
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Affiliation(s)
- W Fuchs
- Institute of Molecular Biology, Friedrich-Loeffler-Institutes, Federal Research Centre for Virus Diseases of Animals, D-17498 Insel Riems, Germany.
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18
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Bergman AC, Nyman PO, Larsson G. Kinetic properties and stereospecificity of the monomeric dUTPase from herpes simplex virus type 1. FEBS Lett 1998; 441:327-30. [PMID: 9883909 DOI: 10.1016/s0014-5793(98)01575-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Kinetic properties of the monomeric enzyme dUTPase from herpes simplex virus type 1 (HSV) were investigated and compared to those previously determined for homotrimeric dUTPases of bacterial and retroviral origins. The HSV and Escherichia coli dUTPases are equally potent as catalysts towards the native substrate dUTP with a kcat/K(M) of about 10(7) M(-1) s(-1) and a K(M) of 0.3 microM. However, the viral enzymes are less specific than the bacterial enzyme. The HSV and E. coli dUTPases show the same stereospecificity towards the racemic substrate analogue dUTPalphaS (2'-deoxyuridine 5'-(alpha-thio)triphosphate), suggesting that they have identical reaction mechanisms.
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Affiliation(s)
- A C Bergman
- Department of Biochemistry, Center for Chemistry and Chemical Engineering, Lund University, Sweden
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