The trans Golgi Network Is Lost from Cells Infected with African Swine Fever Virus

ABSTRACT The cellular secretory pathway is important during the assembly and envelopment of viruses and also controls the transport of host proteins, such as cytokines and major histocompatibility proteins, that function during the elimination of viruses by the immune system. African swine fever virus (ASFV) encodes at least 26 proteins with stretches of hydrophobic amino acids suggesting entry into the secretory pathway (R. J. Yanez, J. M. Rodriguez, M. L. Nogal, L. Yuste, C. Enriquez, J. F. Rodriguez, and E. Vinuela, Virology 208:249–278, 1995). To predict how and where these potential membrane proteins function, we have studied the integrity of the secretory pathway in cells infected with ASFV. Remarkably, ASFV caused complete loss of immunofluorescence signal for the trans Golgi network (TGN) marker protein TGN46 and dispersed the AP1 TGN adapter complex. Loss of TGN46 signal was not due to degradation of TGN46, suggesting redistribution of TGN46 to other membrane compartments. ASFV markedly slowed transport of cathepsin D to lysosomes, demonstrating that loss of TGN structure correlated with loss of TGN function. ASFV shows a tropism for macrophages, and it is possible that ASFV compromises TGN function to augment the activity of viral membrane proteins or to suppress the function of host immunoregulatory proteins.

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African Swine Fever Virus Causes Microtubule-Dependent Dispersal of thetrans-Golgi Network and Slows Delivery of Membrane Protein to the PlasmaMembrane

Journal of Virology ◽

10.1128/jvi.00439-06 ◽

2006 ◽

Vol 80 (22) ◽

pp. 11385-11392 ◽

Cited By ~ 13

Author(s):

Christopher L. Netherton ◽

Mari-Clare McCrossan ◽

Michael Denyer ◽

Sreenivasan Ponnambalam ◽

John Armstrong ◽

...

Keyword(s):

Plasma Membrane ◽

Mhc Class I ◽

Secretory Pathway ◽

African Swine Fever Virus ◽

African Swine Fever ◽

Fever Virus ◽

Class I ◽

Cell Surface Expression ◽

Common Mechanism ◽

Golgi Network

ABSTRACT Viral interference with secretory cargo is a common mechanism for pathogen immune evasion. Selective down regulation of critical immune system molecules such as major histocompatibility complex (MHC) proteins enables pathogens to mask themselves from their host. African swine fever virus (ASFV) disrupts the trans-Golgi network (TGN) by altering the localization of TGN46, an organelle marker for the distal secretory pathway. Reorganization of membrane transport components may provide a mechanism whereby ASFV can disrupt the correct secretion and/or cell surface expression of host proteins. In the study reported here, we used the tsO45 temperature-sensitive mutant of the G protein of vesicular stomatitis virus to show that ASFV significantly reduces the rate at which the protein is delivered to the plasma membrane. This is linked to a general reorganization of the secretory pathway during infection and a specific, microtubule-dependent disruption of structural components of the TGN. Golgin p230 and TGN46 are separated into distinct vesicles, whereupon TGN46 is depleted. These data suggest that disruption of the TGN by ASFV can slow membrane traffic during viral infection. This may be functionally important because infection of macrophages with virulent isolates of ASFV increased the expression of MHC class I genes, but there was no parallel increase in MHC class I molecule delivery to the plasma membrane.

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A Proteomic Atlas of the African Swine Fever Virus Particle

Journal of Virology ◽

10.1128/jvi.01293-18 ◽

2018 ◽

Vol 92 (23) ◽

Cited By ~ 46

Author(s):

Alí Alejo ◽

Tania Matamoros ◽

Milagros Guerra ◽

Germán Andrés

Keyword(s):

Virus Particle ◽

Immunoelectron Microscopy ◽

Protein Modification ◽

Molecular Mechanisms ◽

African Swine Fever Virus ◽

African Swine Fever ◽

Fever Virus ◽

Sub Saharan Africa ◽

Future Research ◽

Host Proteins

ABSTRACTAfrican swine fever virus (ASFV) is a large and complex DNA virus that causes a highly lethal swine disease for which there is no vaccine available. The ASFV particle, with an icosahedral multilayered structure, contains multiple polypeptides whose identity is largely unknown. Here, we analyzed by mass spectroscopy the protein composition of highly purified extracellular ASFV particles and performed immunoelectron microscopy to localize several of the detected proteins. The proteomic analysis identified 68 viral proteins, which account for 39% of the genome coding capacity. The ASFV proteome includes essentially all the previously described virion proteins and, interestingly, 44 newly identified virus-packaged polypeptides, half of which have an unknown function. A great proportion of the virion proteins are committed to the virus architecture, including two newly identified structural proteins, p5 and p8, which are derived from the core polyproteins pp220 and pp62, respectively. In addition, the virion contains a full complement of enzymes and factors involved in viral transcription, various enzymes implicated in DNA repair and protein modification, and some proteins concerned with virus entry and host defense evasion. Finally, 21 host proteins, many of them localized at the cell surface and related to the cortical actin cytoskeleton, were reproducibly detected in the ASFV particle. Immunoelectron microscopy strongly supports the suggestion that these host membrane-associated proteins are recruited during virus budding at actin-dependent membrane protrusions. Altogether, the results of this study provide a comprehensive model of the ASFV architecture that integrates both compositional and structural information.IMPORTANCEAfrican swine fever virus causes a highly contagious and lethal disease of swine that currently affects many countries of sub-Saharan Africa, the Caucasus, the Russian Federation, and Eastern Europe and has very recently spread to China. Despite extensive research, effective vaccines or antiviral strategies are still lacking, and many basic questions on the molecular mechanisms underlying the infective cycle remain. One such gap regards the composition and structure of the infectious virus particle. In the study described in this report, we identified the set of viral and host proteins that compose the virion and determined or inferred the localization of many of them. This information significantly increases our understanding of the biological and structural features of an infectious African swine fever virus particle and will help direct future research efforts.

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The MGF360-16R ORF of African Swine Fever Virus Strain Georgia Encodes for a Nonessential Gene That Interacts with Host Proteins SERTAD3 and SDCBP

Viruses ◽

10.3390/v12010060 ◽

2020 ◽

Vol 12 (1) ◽

pp. 60 ◽

Cited By ~ 4

Author(s):

Elizabeth Ramírez-Medina ◽

Elizabeth A. Vuono ◽

Lauro Velazquez-Salinas ◽

Ediane Silva ◽

Ayushi Rai ◽

...

Keyword(s):

African Swine Fever Virus ◽

Field Isolate ◽

African Swine Fever ◽

Fever Virus ◽

Host Protein ◽

Parental Virus ◽

Virus Protein ◽

Host Proteins ◽

Swine Industry ◽

Nonessential Gene

African swine fever virus (ASFV) causes a contagious and frequently lethal disease of pigs with significant economic consequences to the swine industry. The ASFV genome encodes for more than 160 genes, but only a few of them have been studied in detail. Here we report the characterization of open reading frame (ORF) MGF360-16R. Kinetic studies of virus RNA transcription demonstrated that the MGF360-16R gene is transcribed as a late virus protein. Analysis of host–protein interactions for the MGF360-16R gene using a yeast two-hybrid screen identified SERTA domain containing 3 (SERTAD3) and syndecan-binding protein (SDCBP) as host protein binding partners. SERTAD3 and SDCBP are both involved in nuclear transcription and SDCBP has been shown to be involved in virus traffic inside the host cell. Interaction between MGF360-16R and SERTAD3 and SDCBP host proteins was confirmed in eukaryotic cells transfected with plasmids expressing MGF360-16R and SERTAD3 or SDCBP fused to fluorescent tags. A recombinant ASFV lacking the MGF360-16R gene (ASFV-G-ΔMGF360-16R) was developed from the highly virulent field isolate Georgia2007 (ASFV-G) and was used to show that MGF360-16R is a nonessential gene. ASFV-G-ΔMGF360-16R had a similar replication ability in primary swine macrophage cell cultures when compared to its parental virus ASFV-G. Experimental infection of domestic pigs showed that ASFV-G-ΔMGF360-16R is as virulent as the parental virus ASFV-G.

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