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Wöhnke E, Cackett G, Werner F, Blome S, Mettenleiter TC, Karger A. Proteome Analysis of Swine Macrophages after Infection with Two Genotype II African Swine Fever Isolates of Different Pathogenicity. Viruses 2022; 14:v14102140. [PMID: 36298696 PMCID: PMC9607119 DOI: 10.3390/v14102140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Revised: 09/25/2022] [Accepted: 09/26/2022] [Indexed: 11/17/2022] Open
Abstract
Since the introduction of a highly pathogenic genotype II isolate of the African swine fever virus (ASFV) into Georgia in 2007, African swine fever (ASF) has gone panzootic. Outbreaks have been reported in Europe, Asia and, more recently, Latin America. Thus, ASFV has become a major threat to the pig industry worldwide, as broadly applicable vaccines are not available. While the majority of ASFV strains show high virulence in domestic pigs and wild boar, variations within the ASFV genome have resulted in the emergence of attenuated strains with low or moderate virulence. However, the molecular basis of the differences in virulence has not yet been discovered. To reveal virulence-associated protein expression patterns, we analysed the proteomes of the natural target cells of ASFV, primary porcine macrophages, after infection with two genotype II ASFV strains displaying high (Armenia 2008) and moderate (Estonia 2014) virulence using quantitative mass spectrometry. Very similar expression patterns were observed for the viral genes, and any differences were limited to the deletions within the Estonia 2014 genome. In addition to the canonical ASFV proteins, twelve novel protein products from recently described transcripts were confirmed in both isolates. Pathway analyses showed that both isolates evoked a similar host proteome response, despite their difference in virulence. However, subtle differences in the manipulation of the proteins involved in the proinflammatory response mediated by the MAPK14/p38 signalling cascade were observed.
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Affiliation(s)
- Elisabeth Wöhnke
- Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Südufer 10, 17493 Greifswald, Germany
| | - Gwenny Cackett
- Institute for Structural and Molecular Biology, Darwin Building, University College London, Gower Street, London WC1E 6BT, UK
| | - Finn Werner
- Institute for Structural and Molecular Biology, Darwin Building, University College London, Gower Street, London WC1E 6BT, UK
| | - Sandra Blome
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Südufer 10, 17493 Greifswald, Germany
| | - Thomas C. Mettenleiter
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Südufer 10, 17493 Greifswald, Germany
| | - Axel Karger
- Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Südufer 10, 17493 Greifswald, Germany
- Correspondence: ; Tel.: +49-38351-7-1247
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Duan X, Ru Y, Yang W, Ren J, Hao R, Qin X, Li D, Zheng H. Research progress on the proteins involved in African swine fever virus infection and replication. Front Immunol 2022; 13:947180. [PMID: 35935977 PMCID: PMC9353306 DOI: 10.3389/fimmu.2022.947180] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Accepted: 06/28/2022] [Indexed: 12/02/2022] Open
Abstract
African swine fever (ASF) is an acute, hemorrhagic and highly contagious infectious disease caused by African swine fever virus (ASFV), which infects domestic pigs or wild boars. It is characterized by short course of disease, high fever and hemorrhagic lesions, with mortality of up to 100% from acute infection. Up to now, the lack of commercial vaccines and effective drugs has seriously threatened the healthy economic development of the global pig industry. ASFV is a double-stranded DNA virus and genome varies between about 170-194 kb, which encodes 150-200 viral proteins, including 68 structural proteins and more than 100 non-structural proteins. In recent years, although the research on structure and function of ASFV-encoded proteins has been deepened, the structure and infection process of ASFV are still not clear. This review summarizes the main process of ASFV infection, replication and functions of related viral proteins to provide scientific basis and theoretical basis for ASFV research and vaccine development.
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Affiliation(s)
- Xianghan Duan
- State Key Laboratory of Veterinary Etiological Biology and OIE/National Foot and Mouth Disease Reference Laboratory, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China
| | - Yi Ru
- State Key Laboratory of Veterinary Etiological Biology and OIE/National Foot and Mouth Disease Reference Laboratory, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China
| | - Wenping Yang
- State Key Laboratory of Veterinary Etiological Biology and OIE/National Foot and Mouth Disease Reference Laboratory, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China
| | - Jingjing Ren
- State Key Laboratory of Veterinary Etiological Biology and OIE/National Foot and Mouth Disease Reference Laboratory, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China
| | - Rongzeng Hao
- State Key Laboratory of Veterinary Etiological Biology and OIE/National Foot and Mouth Disease Reference Laboratory, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China
| | - Xiaodong Qin
- State Key Laboratory of Veterinary Etiological Biology and OIE/National Foot and Mouth Disease Reference Laboratory, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China
| | - Dan Li
- State Key Laboratory of Veterinary Etiological Biology and OIE/National Foot and Mouth Disease Reference Laboratory, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China
- State Key Laboratory of Veterinary Etiological Biology, College of Veterinary Medicine, Lanzhou University, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China
| | - Haixue Zheng
- State Key Laboratory of Veterinary Etiological Biology and OIE/National Foot and Mouth Disease Reference Laboratory, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China
- State Key Laboratory of Veterinary Etiological Biology, College of Veterinary Medicine, Lanzhou University, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China
- *Correspondence: Haixue Zheng,
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Zajac MD, Sangewar N, Lokhandwala S, Bray J, Sang H, McCall J, Bishop RP, Waghela SD, Kumar R, Kim T, Mwangi W. Adenovirus-Vectored African Swine Fever Virus pp220 Induces Robust Antibody, IFN-γ, and CTL Responses in Pigs. Front Vet Sci 2022; 9:921481. [PMID: 35711803 PMCID: PMC9195138 DOI: 10.3389/fvets.2022.921481] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Accepted: 05/02/2022] [Indexed: 11/13/2022] Open
Abstract
African Swine Fever Virus (ASFV) poses a serious threat to the pork industry worldwide; however, there is no safe vaccine or treatment available. The development of an efficacious subunit vaccine will require the identification of protective antigens. The ASFV pp220 polyprotein is essential for virus structural integrity. This polyprotein is processed to generate p5, p34, p14, p37, and p150 individual proteins. Immunization of pigs with a cocktail of adenoviruses expressing the proteins induced significant IgG, IFN-γ-secreting cells, and cytotoxic T lymphocyte responses. Four predicted SLA-I binding nonamer peptides, namely p34161−169, p37859−867, p1501363−1371, and p1501463−1471, recalled strong IFN-γ+ PBMC and splenocyte responses. Notably, peptide p34161−169 was recognized by PBMCs isolated from 7/10 pigs and by splenocytes isolated from 8/10 pigs. Peptides p37859−867 and p1501363−1371 stimulated recall IFN-γ+ responses in PBMCs and splenocytes isolated from 8/10 pigs, whereas peptide p1501463−1471 recalled responses in PBMCs and splenocytes isolated from 7/10 to 9/10 pigs, respectively. The results demonstrate that the pp220 polyprotein contains multiple epitopes that induce robust immune responses in pigs. Importantly, these epitopes are 100% conserved among different ASFV genotypes and were predicted to bind multiple SLA-I alleles. The outcomes suggest that pp220 is a promising candidate for inclusion in a prototype subunit vaccine.
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Affiliation(s)
- Michelle D. Zajac
- Department of Diagnostic Medicine/Pathobiology, Kansas State University, Manhattan, KS, United States
- *Correspondence: Michelle D. Zajac
| | - Neha Sangewar
- Department of Diagnostic Medicine/Pathobiology, Kansas State University, Manhattan, KS, United States
| | - Shehnaz Lokhandwala
- Department of Diagnostic Medicine/Pathobiology, Kansas State University, Manhattan, KS, United States
| | - Jocelyne Bray
- Department of Veterinary Pathobiology, Texas A&M University, College Station, TX, United States
| | - Huldah Sang
- Department of Diagnostic Medicine/Pathobiology, Kansas State University, Manhattan, KS, United States
| | - Jayden McCall
- Department of Diagnostic Medicine/Pathobiology, Kansas State University, Manhattan, KS, United States
| | - Richard P. Bishop
- Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, WA, United States
| | - Suryakant D. Waghela
- Department of Veterinary Pathobiology, Texas A&M University, College Station, TX, United States
| | - Rakshith Kumar
- Department of Diagnostic Medicine/Pathobiology, Kansas State University, Manhattan, KS, United States
| | - Tae Kim
- Department of Diagnostic Medicine/Pathobiology, Kansas State University, Manhattan, KS, United States
| | - Waithaka Mwangi
- Department of Diagnostic Medicine/Pathobiology, Kansas State University, Manhattan, KS, United States
- Waithaka Mwangi
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Jia N, Ou Y, Pejsak Z, Zhang Y, Zhang J. Roles of African Swine Fever Virus Structural Proteins in Viral Infection. J Vet Res 2017; 61:135-143. [PMID: 29978065 PMCID: PMC5894393 DOI: 10.1515/jvetres-2017-0017] [Citation(s) in RCA: 69] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2017] [Accepted: 05/25/2017] [Indexed: 11/15/2022] Open
Abstract
African swine fever virus (ASFV) is a large, double-stranded DNA virus and the sole member of the Asfarviridae family. ASFV infects domestic pigs, wild boars, warthogs, and bush pigs, as well as soft ticks (Ornithodoros erraticus), which likely act as a vector. The major target is swine monocyte-macrophage cells. The virus can cause high fever, haemorrhagic lesions, cyanosis, anorexia, and even fatalities in domestic pigs. Currently, there is no vaccine and effective disease control strategies against its spread are culling infected pigs and maintaining high biosecurity standards. African swine fever (ASF) spread to Europe from Africa in the middle of the 20th century, and later also to South America and the Caribbean. Since then, ASF has spread more widely and thus is still a great challenge for swine breeding. The genome of ASFV ranges in length from about 170 to 193 kbp depending on the isolate and contains between 150 and 167 open reading frames (ORFs). The ASFV genome encodes 150 to 200 proteins, around 50 of them structural. The roles of virus structural proteins in viral infection have been described. These proteins, such as pp220, pp62, p72, p54, p30, and CD2v, serve as the major component of virus particles and have roles in attachment, entry, and replication. All studies on ASFV proteins lay a good foundation upon which to clarify the infection mechanism and develop vaccines and diagnosis methods. In this paper, the roles of ASFV structural proteins in viral infection are reviewed.
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Affiliation(s)
- Ning Jia
- College of Veterinary Medicine, Gansu Agricultural University, Lanzhou 730070, China
| | - Yunwen Ou
- College of Veterinary Medicine, Gansu Agricultural University, Lanzhou 730070, China.,State Key Laboratory of Veterinary Etiological Biology, OIE/National Foot-and-Mouth Disease Reference Laboratory, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou 730046, China
| | - Zygmunt Pejsak
- Department of Swine Diseases, National Veterinary Research Institute, 24-100 Pulawy, Poland
| | - Yongguang Zhang
- State Key Laboratory of Veterinary Etiological Biology, OIE/National Foot-and-Mouth Disease Reference Laboratory, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou 730046, China
| | - Jie Zhang
- State Key Laboratory of Veterinary Etiological Biology, OIE/National Foot-and-Mouth Disease Reference Laboratory, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou 730046, China
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5
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Burrage TG. African swine fever virus infection in Ornithodoros ticks. Virus Res 2012; 173:131-9. [PMID: 23085123 DOI: 10.1016/j.virusres.2012.10.010] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2012] [Revised: 09/29/2012] [Accepted: 10/07/2012] [Indexed: 01/08/2023]
Abstract
African swine fever virus (ASFV) is an arbovirus which is vectored by soft ticks of the Ornithodoros spp. and in the sylvatic cycle infects wart hogs and bush pigs. ASFV infection of domestic swine causes a high mortality disease. On the other hand, ASFV infection of the tick can result in a high-titered and persistent infection depending upon the ASFV isolate and the tick combination. Recently, morphological, classical virology (titration) and recombinant ASFV have been used to study the cellular, molecular and genetic interactions that occur between ASFV and its host tick.
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Affiliation(s)
- Thomas G Burrage
- Department of Homeland Security, S & T, Targeted Advance Development, Virus, Cellular and Molecular Imaging, PO Box 848, Plum Island Animal Disease Center, Greenport, NY 11944, United States.
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Windsor M, Hawes P, Monaghan P, Snapp E, Salas ML, Rodríguez JM, Wileman T. Mechanism of collapse of endoplasmic reticulum cisternae during African swine fever virus infection. Traffic 2011; 13:30-42. [PMID: 21951707 DOI: 10.1111/j.1600-0854.2011.01293.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Infection of cells with African swine fever virus (ASFV) can lead to the formation of zipper-like stacks of structural proteins attached to collapsed endoplasmic reticulum (ER) cisternae. We show that the collapse of ER cisternae observed during ASFV infection is dependent on the viral envelope protein, J13Lp. Expression of J13Lp alone in cells is sufficient to induce collapsed ER cisternae. Collapse was dependent on a cysteine residue in the N-terminal domain of J13Lp exposed to the ER lumen. Luminal collapse was also dependent on the expression of J13Lp within stacks of ER where antiparallel interactions between the cytoplasmic domains of J13Lp orientated N-terminal domains across ER cisternae. Cisternal collapse was then driven by disulphide bonds between N-terminal domains arranged in antiparallel arrays across the ER lumen. This provides a novel mechanism for biogenesis of modified stacks of ER present in cells infected with ASFV, and may also be relevant to cellular processes.
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Affiliation(s)
- Miriam Windsor
- Institute for Animal Health, Pirbright Laboratory, Surrey, UK
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7
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Abstract
African swine fever virus (ASFV) is a large, intracytoplasmically-replicating DNA arbovirus and the sole member of the family Asfarviridae. It is the etiologic agent of a highly lethal hemorrhagic disease of domestic swine and therefore extensively studied to elucidate the structures, genes, and mechanisms affecting viral replication in the host, virus-host interactions, and viral virulence. Increasingly apparent is the complexity with which ASFV replicates and interacts with the host cell during infection. ASFV encodes novel genes involved in host immune response modulation, viral virulence for domestic swine, and in the ability of ASFV to replicate and spread in its tick vector. The unique nature of ASFV has contributed to a broader understanding of DNA virus/host interactions.
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Affiliation(s)
- E R Tulman
- Department of Pathobiology and Veterinary Science, Center of Excellence for Vaccine Research, University of Connecticut, Storrs 06269, USA.
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Armer H, Moffat K, Wileman T, Belsham GJ, Jackson T, Duprex WP, Ryan M, Monaghan P. Foot-and-mouth disease virus, but not bovine enterovirus, targets the host cell cytoskeleton via the nonstructural protein 3Cpro. J Virol 2008; 82:10556-66. [PMID: 18753210 PMCID: PMC2573224 DOI: 10.1128/jvi.00907-08] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2008] [Accepted: 08/13/2008] [Indexed: 12/20/2022] Open
Abstract
Foot-and-mouth disease virus (FMDV), a member of the Picornaviridae, is a pathogen of cloven-hoofed animals and causes a disease of major economic importance. Picornavirus-infected cells show changes in cell morphology and rearrangement of cytoplasmic membranes, which are a consequence of virus replication. We show here, by confocal immunofluorescence and electron microscopy, that the changes in morphology of FMDV-infected cells involve changes in the distribution of microtubule and intermediate filament components during infection. Despite the continued presence of centrosomes in infected cells, there is a loss of tethering of microtubules to the microtubule organizing center (MTOC) region. Loss of labeling for gamma-tubulin, but not pericentrin, from the MTOC suggests a targeting of gamma-tubulin (or associated proteins) rather than a total breakdown in MTOC structure. The identity of the FMDV protein(s) responsible was determined by the expression of individual viral nonstructural proteins and their precursors in uninfected cells. We report that the only viral nonstructural protein able to reproduce the loss of gamma-tubulin from the MTOC and the loss of integrity of the microtubule system is FMDV 3C(pro). In contrast, infection of cells with another picornavirus, bovine enterovirus, did not affect gamma-tubulin distribution, and the microtubule network remained relatively unaffected.
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Affiliation(s)
- Hannah Armer
- Institute for Animal Health, Woking, Surrey, United Kingdom
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Netherton C, Moffat K, Brooks E, Wileman T. A guide to viral inclusions, membrane rearrangements, factories, and viroplasm produced during virus replication. Adv Virus Res 2007; 70:101-82. [PMID: 17765705 PMCID: PMC7112299 DOI: 10.1016/s0065-3527(07)70004-0] [Citation(s) in RCA: 164] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Virus replication can cause extensive rearrangement of host cell cytoskeletal and membrane compartments leading to the “cytopathic effect” that has been the hallmark of virus infection in tissue culture for many years. Recent studies are beginning to redefine these signs of viral infection in terms of specific effects of viruses on cellular processes. In this chapter, these concepts have been illustrated by describing the replication sites produced by many different viruses. In many cases, the cellular rearrangements caused during virus infection lead to the construction of sophisticated platforms in the cell that concentrate replicase proteins, virus genomes, and host proteins required for replication, and thereby increase the efficiency of replication. Interestingly, these same structures, called virus factories, virus inclusions, or virosomes, can recruit host components that are associated with cellular defences against infection and cell stress. It is possible that cellular defence pathways can be subverted by viruses to generate sites of replication. The recruitment of cellular membranes and cytoskeleton to generate virus replication sites can also benefit viruses in other ways. Disruption of cellular membranes can, for example, slow the transport of immunomodulatory proteins to the surface of infected cells and protect against innate and acquired immune responses, and rearrangements to cytoskeleton can facilitate virus release.
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Affiliation(s)
- Christopher Netherton
- Vaccinology Group, Pirbright Laboratories, Institute for Animal Health, Surrey, United Kingdom
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Cobbold C, Windsor M, Parsley J, Baldwin B, Wileman T. Reduced redox potential of the cytosol is important for African swine fever virus capsid assembly and maturation. J Gen Virol 2007; 88:77-85. [PMID: 17170439 DOI: 10.1099/vir.0.82257-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Assembly of African swine fever virus (ASFV) involves the transfer of the major capsid protein, p73, from the cytosol onto the cytoplasmic face of endoplasmic reticulum-derived membranes. During this process, the folding of p73 is dependent upon transient association with a specific viral chaperone, CAP80. The cell cytoplasm maintains high concentrations of reduced glutathione, leading to a reducing environment. Here, the effects of redox environment on the assembly of ASFV have been studied. Diamide, which oxidizes the cell cytosol, slowed the folding of p73 and prevented release from CAP80 and subsequent binding of p73 to membranes. Similarly, cell oxidation slowed the assembly of p73 molecules already bound to membranes into virus capsid precursors. Interestingly, addition of oxidized glutathione to newly assembled virus capsid precursors in vitro led to disassembly; however, virus particles released from cells were resistant to oxidized glutathione. These data show that assembly of ASFV requires the reducing environment that prevails in the cytosol, but as the virus matures, it becomes resistant to oxidation, possibly indicating preparation for release from the cell.
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Affiliation(s)
- Christian Cobbold
- Department of Biomedical and Biomolecular Sciences, Griffith University, Nathan, QLD 4111, Australia
| | - Miriam Windsor
- Division of Immunology, Institute for Animal Health, Pirbright Laboratories, Woking, Surrey GU24 0NF, UK
| | - James Parsley
- Division of Immunology, Institute for Animal Health, Pirbright Laboratories, Woking, Surrey GU24 0NF, UK
| | - Ben Baldwin
- Department of Biomedical and Biomolecular Sciences, Griffith University, Nathan, QLD 4111, Australia
| | - Thomas Wileman
- Division of Immunology, Institute for Animal Health, Pirbright Laboratories, Woking, Surrey GU24 0NF, UK
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Stefanovic S, Windsor M, Nagata KI, Inagaki M, Wileman T. Vimentin rearrangement during African swine fever virus infection involves retrograde transport along microtubules and phosphorylation of vimentin by calcium calmodulin kinase II. J Virol 2005; 79:11766-75. [PMID: 16140754 PMCID: PMC1212593 DOI: 10.1128/jvi.79.18.11766-11775.2005] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
African swine fever virus (ASFV) infection leads to rearrangement of vimentin into a cage surrounding virus factories. Vimentin rearrangement in cells generally involves phosphorylation of N-terminal domains of vimentin by cellular kinases to facilitate disassembly and transport of vimentin filaments on microtubules. Here, we demonstrate that the first stage in vimentin rearrangement during ASFV infection involves a microtubule-dependent concentration of vimentin into an "aster" within virus assembly sites located close to the microtubule organizing center. The aster may play a structural role early during the formation of the factory. Conversion of the aster into a cage required ASFV DNA replication. Interestingly, viral DNA replication also resulted in the activation of calcium calmodulin-dependent protein kinase II (CaM kinase II) and phosphorylation of the N-terminal domain of vimentin on serine 82. Immunostaining showed that vimentin within the cage was phosphorylated on serine 82. Significantly, both viral DNA replication and Ser 82 phosphorylation were blocked by KN93, an inhibitor of CaM kinase II, suggesting a link between CaM kinase II activation, DNA replication, and late gene expression. Phosphorylation of vimentin on serine 82 may be necessary for cage formation or may simply be a consequence of activation of CaM kinase II by ASFV. The vimentin cage may serve a cytoprotective function and prevent movement of viral components into the cytoplasm and at the same time concentrate late structural proteins at sites of virus assembly.
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Affiliation(s)
- Sandra Stefanovic
- Division of Immunology, Pirbright Laboratories, Institute for Animal Health, Surrey Ash Road, Woking, Surrey GU24 ONF, United Kingdom
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12
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Jouvenet N, Monaghan P, Way M, Wileman T. Transport of African swine fever virus from assembly sites to the plasma membrane is dependent on microtubules and conventional kinesin. J Virol 2004; 78:7990-8001. [PMID: 15254171 PMCID: PMC446130 DOI: 10.1128/jvi.78.15.7990-8001.2004] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
African swine fever virus (ASFV) is a large DNA virus that assembles in perinuclear viral factories located close to the microtubule organizing center. In this study, we have investigated the mechanism by which ASFV reaches the cell surface from the site of assembly. Immunofluorescence microscopy revealed that at 16 h postinfection, mature virions were aligned along microtubules. Furthermore, virus movement to the cell periphery was inhibited when microtubules were depolymerized by nocodazole. In addition, ASFV infection resulted in the increased acetylation of microtubules as well as their protection against depolymerization by nocodazole. Immunofluorescence microscopy showed that conventional kinesin was recruited to virus factories and to a large fraction of virus particles in the cytoplasm. Consistent with a role for conventional kinesin during ASFV egress to the cell periphery, overexpression of the cargo-binding domain of the kinesin light chain severely inhibited the movement of particles to the plasma membrane. Based on our observations, we propose that ASFV is recognized as cargo by conventional kinesin and uses this plus-end microtubule motor to move from perinuclear assembly sites to the plasma membrane.
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Affiliation(s)
- Nolwenn Jouvenet
- Department of Immunology and Pathology, Institute for Animal Health, Surrey GU24 0NF, United Kingdom
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Rodríguez JM, García-Escudero R, Salas ML, Andrés G. African swine fever virus structural protein p54 is essential for the recruitment of envelope precursors to assembly sites. J Virol 2004; 78:4299-1313. [PMID: 15047843 PMCID: PMC374266 DOI: 10.1128/jvi.78.8.4299-4313.2004] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The assembly of African swine fever virus (ASFV) at the cytoplasmic virus factories commences with the formation of precursor membranous structures, which are thought to be collapsed cisternal domains recruited from the surrounding endoplasmic reticulum (ER). This report analyzes the role in virus morphogenesis of the structural protein p54, a 25-kDa polypeptide encoded by the E183L gene that contains a putative transmembrane domain and localizes at the ER-derived envelope precursors. We show that protein p54 behaves in vitro and in infected cells as a type I membrane-anchored protein that forms disulfide-linked homodimers through its unique luminal cysteine. Moreover, p54 is targeted to the ER membranes when it is transiently expressed in transfected cells. Using a lethal conditional recombinant, vE183Li, we also demonstrate that the repression of p54 synthesis arrests virus morphogenesis at a very early stage, even prior to the formation of the precursor membranes. Under restrictive conditions, the virus factories appeared as discrete electron-lucent areas essentially free of viral structures. In contrast, outside the assembly sites, large amounts of aberrant zipper-like structures formed by the unprocessed core polyproteins pp220 and pp62 were produced in close association to ER cisternae. Altogether, these results indicate that the transmembrane structural protein p54 is critical for the recruitment and transformation of the ER membranes into the precursors of the viral envelope.
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Affiliation(s)
- Javier M Rodríguez
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid, Facultad de Ciencias, Cantoblanco, 28049 Madrid, Spain
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14
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Satheshkumar PS, Lokesh GL, Savithri HS. Polyprotein processing: cis and trans proteolytic activities of Sesbania mosaic virus serine protease. Virology 2004; 318:429-38. [PMID: 14972568 DOI: 10.1016/j.virol.2003.09.035] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2003] [Revised: 09/22/2003] [Accepted: 09/23/2003] [Indexed: 11/16/2022]
Abstract
Sesbania mosaic virus (SeMV) polyprotein was shown to undergo proteolytic processing when expressed in E. coli. Mutational analysis of the proposed catalytic triad residues (H181, D216, and S284) present in the N-terminal serine protease domain of the polyprotein showed that the protease was indeed responsible for this processing. Analysis of the cleavage site mutants confirmed the cleavage between protease-viral protein genome linked (VPg) and VPg-RNA-dependent RNA polymerase (RdRP) at E(325)-T(326) and E(402)-T(403) sites, respectively. An additional suboptimal cleavage at E(498)-S(499) site was also identified which resulted in the further processing of RdRP to 10- and 52-kDa proteins. Thus, the protease has both E-T and E-S specificities. The polyprotein has a domain arrangement of protease-VPg-p10-RdRP, which is cleaved by the protease. The purified serine protease was also active in trans and cleaved the polyprotein at the same specific sites. These results demonstrate that the serine protease domain is responsible for the processing of SeMV polyprotein both in cis and in trans.
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Affiliation(s)
- P S Satheshkumar
- Department of Biochemistry, Indian Institute of Science, Bangalore, 560 012, India
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