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Bluetongue Virus Nonstructural Protein 3 Orchestrates Virus Maturation and Drives Non-Lytic Egress via Two Polybasic Motifs

Bluetongue virus (BTV) is an arthropod-borne virus that infects domestic and wild ruminants. The virion is a non-enveloped double-layered particle with an outer capsid that encloses a core containing the segmented double-stranded RNA genome. Although BTV is canonically released by cell lysis, it als...

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Autores principales: Labadie, Thomas, Jegouic, Sophie, Roy, Polly
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2019
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6949946/
https://www.ncbi.nlm.nih.gov/pubmed/31795485
http://dx.doi.org/10.3390/v11121107
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author Labadie, Thomas
Jegouic, Sophie
Roy, Polly
author_facet Labadie, Thomas
Jegouic, Sophie
Roy, Polly
author_sort Labadie, Thomas
collection PubMed
description Bluetongue virus (BTV) is an arthropod-borne virus that infects domestic and wild ruminants. The virion is a non-enveloped double-layered particle with an outer capsid that encloses a core containing the segmented double-stranded RNA genome. Although BTV is canonically released by cell lysis, it also exits non-lytically. In infected cells, the BTV nonstructural glycoprotein 3 (NS3) is found to be associated with host membranes and traffics from the endoplasmic reticulum through the Golgi apparatus to the plasma membrane. This suggests a role for NS3 in BTV particle maturation and non-lytic egress. However, the mechanism by which NS3 coordinates these events has not yet been elucidated. Here, we identified two polybasic motifs (PMB1/PMB2), consistent with the membrane binding. Using site-directed mutagenesis, confocal and electron microscopy, and flow cytometry, we demonstrated that PBM1 and PBM2 mutant viruses retained NS3 either in the Golgi apparatus or in the endoplasmic reticulum, suggesting a distinct role for each motif. Mutation of PBM2 motif decreased NS3 export to the cell surface and virus production. However, both mutant viruses produced predominantly inner core particles that remained close to their site of assembly. Together, our data demonstrates that correct trafficking of the NS3 protein is required for virus maturation and release.
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spelling pubmed-69499462020-01-16 Bluetongue Virus Nonstructural Protein 3 Orchestrates Virus Maturation and Drives Non-Lytic Egress via Two Polybasic Motifs Labadie, Thomas Jegouic, Sophie Roy, Polly Viruses Article Bluetongue virus (BTV) is an arthropod-borne virus that infects domestic and wild ruminants. The virion is a non-enveloped double-layered particle with an outer capsid that encloses a core containing the segmented double-stranded RNA genome. Although BTV is canonically released by cell lysis, it also exits non-lytically. In infected cells, the BTV nonstructural glycoprotein 3 (NS3) is found to be associated with host membranes and traffics from the endoplasmic reticulum through the Golgi apparatus to the plasma membrane. This suggests a role for NS3 in BTV particle maturation and non-lytic egress. However, the mechanism by which NS3 coordinates these events has not yet been elucidated. Here, we identified two polybasic motifs (PMB1/PMB2), consistent with the membrane binding. Using site-directed mutagenesis, confocal and electron microscopy, and flow cytometry, we demonstrated that PBM1 and PBM2 mutant viruses retained NS3 either in the Golgi apparatus or in the endoplasmic reticulum, suggesting a distinct role for each motif. Mutation of PBM2 motif decreased NS3 export to the cell surface and virus production. However, both mutant viruses produced predominantly inner core particles that remained close to their site of assembly. Together, our data demonstrates that correct trafficking of the NS3 protein is required for virus maturation and release. MDPI 2019-11-29 /pmc/articles/PMC6949946/ /pubmed/31795485 http://dx.doi.org/10.3390/v11121107 Text en © 2019 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Labadie, Thomas
Jegouic, Sophie
Roy, Polly
Bluetongue Virus Nonstructural Protein 3 Orchestrates Virus Maturation and Drives Non-Lytic Egress via Two Polybasic Motifs
title Bluetongue Virus Nonstructural Protein 3 Orchestrates Virus Maturation and Drives Non-Lytic Egress via Two Polybasic Motifs
title_full Bluetongue Virus Nonstructural Protein 3 Orchestrates Virus Maturation and Drives Non-Lytic Egress via Two Polybasic Motifs
title_fullStr Bluetongue Virus Nonstructural Protein 3 Orchestrates Virus Maturation and Drives Non-Lytic Egress via Two Polybasic Motifs
title_full_unstemmed Bluetongue Virus Nonstructural Protein 3 Orchestrates Virus Maturation and Drives Non-Lytic Egress via Two Polybasic Motifs
title_short Bluetongue Virus Nonstructural Protein 3 Orchestrates Virus Maturation and Drives Non-Lytic Egress via Two Polybasic Motifs
title_sort bluetongue virus nonstructural protein 3 orchestrates virus maturation and drives non-lytic egress via two polybasic motifs
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6949946/
https://www.ncbi.nlm.nih.gov/pubmed/31795485
http://dx.doi.org/10.3390/v11121107
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