Mutation of the N-Terminal Region of Chikungunya Virus Capsid Protein: Implications for Vaccine Design

ABSTRACT Mosquito-transmitted chikungunya virus (CHIKV) is an arthritogenic alphavirus of the Togaviridae family responsible for frequent outbreaks of arthritic disease in humans. Capsid protein, a structural protein encoded by the CHIKV RNA genome, is able to translocate to the host cell nucleolus....

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Autores principales:	Adam Taylor, Xiang Liu, Ali Zaid, Lucas Y. H. Goh, Jody Hobson-Peters, Roy A. Hall, Andres Merits, Suresh Mahalingam
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Publicado:	American Society for Microbiology 2017
Materias:	Microbiology QR1-502
Acceso en línea:	https://doaj.org/article/81b757c4f7e64d60899db9b431272658
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spelling	oai:doaj.org-article:81b757c4f7e64d60899db9b4312726582021-11-15T15:51:07ZMutation of the N-Terminal Region of Chikungunya Virus Capsid Protein: Implications for Vaccine Design10.1128/mBio.01970-162150-7511https://doaj.org/article/81b757c4f7e64d60899db9b4312726582017-03-01T00:00:00Zhttps://journals.asm.org/doi/10.1128/mBio.01970-16https://doaj.org/toc/2150-7511ABSTRACT Mosquito-transmitted chikungunya virus (CHIKV) is an arthritogenic alphavirus of the Togaviridae family responsible for frequent outbreaks of arthritic disease in humans. Capsid protein, a structural protein encoded by the CHIKV RNA genome, is able to translocate to the host cell nucleolus. In encephalitic alphaviruses, nuclear translocation induces host cell transcriptional shutoff; however, the role of capsid protein nucleolar localization in arthritogenic alphaviruses remains unclear. Using recombinant enhanced green fluorescent protein (EGFP)-tagged expression constructs and CHIKV infectious clones, we describe a nucleolar localization sequence (NoLS) in the N-terminal region of capsid protein, previously uncharacterized in CHIKV. Mutation of the NoLS by site-directed mutagenesis reduced efficiency of nuclear import of CHIKV capsid protein. In the virus, mutation of the capsid protein NoLS (CHIKV-NoLS) attenuated replication in mammalian and mosquito cells, producing a small-plaque phenotype. Attenuation of CHIKV-NoLS is likely due to disruption of the viral replication cycle downstream of viral RNA synthesis. In mice, CHIKV-NoLS infection caused no disease signs compared to wild-type CHIKV (CHIKV-WT)-infected mice; lack of disease signs correlated with significantly reduced viremia and decreased expression of proinflammatory factors. Mice immunized with CHIKV-NoLS, challenged with CHIKV-WT at 30 days postimmunization, develop no disease signs and no detectable viremia. Serum from CHIKV-NoLS-immunized mice is able to efficiently neutralize CHIKV infection in vitro. Additionally, CHIKV-NoLS-immunized mice challenged with the related alphavirus Ross River virus showed reduced early and peak viremia postchallenge, indicating a cross-protective effect. The high degree of CHIKV-NoLS attenuation may improve CHIKV antiviral and rational vaccine design. IMPORTANCE CHIKV is a mosquito-borne pathogen capable of causing explosive epidemics of incapacitating joint pain affecting millions of people. After a series of major outbreaks over the last 10 years, CHIKV and its mosquito vectors have been able to expand their range extensively, now making CHIKV a human pathogen of global importance. With no licensed vaccine or antiviral therapy for the treatment of CHIKV disease, there is a growing need to understand the molecular determinants of viral pathogenesis. These studies identify a previously uncharacterized nucleolar localization sequence (NoLS) in CHIKV capsid protein, begin a functional analysis of site-directed mutants of the capsid protein NoLS, and examine the effect of the NoLS mutation on CHIKV pathogenesis in vivo and its potential to influence CHIKV vaccine design. A better understanding of the pathobiology of CHIKV disease will aid the development of effective therapeutic strategies.Adam TaylorXiang LiuAli ZaidLucas Y. H. GohJody Hobson-PetersRoy A. HallAndres MeritsSuresh MahalingamAmerican Society for MicrobiologyarticleMicrobiologyQR1-502ENmBio, Vol 8, Iss 1 (2017)
institution	DOAJ
collection	DOAJ
language	EN
topic	Microbiology QR1-502
spellingShingle	Microbiology QR1-502 Adam Taylor Xiang Liu Ali Zaid Lucas Y. H. Goh Jody Hobson-Peters Roy A. Hall Andres Merits Suresh Mahalingam Mutation of the N-Terminal Region of Chikungunya Virus Capsid Protein: Implications for Vaccine Design
description	ABSTRACT Mosquito-transmitted chikungunya virus (CHIKV) is an arthritogenic alphavirus of the Togaviridae family responsible for frequent outbreaks of arthritic disease in humans. Capsid protein, a structural protein encoded by the CHIKV RNA genome, is able to translocate to the host cell nucleolus. In encephalitic alphaviruses, nuclear translocation induces host cell transcriptional shutoff; however, the role of capsid protein nucleolar localization in arthritogenic alphaviruses remains unclear. Using recombinant enhanced green fluorescent protein (EGFP)-tagged expression constructs and CHIKV infectious clones, we describe a nucleolar localization sequence (NoLS) in the N-terminal region of capsid protein, previously uncharacterized in CHIKV. Mutation of the NoLS by site-directed mutagenesis reduced efficiency of nuclear import of CHIKV capsid protein. In the virus, mutation of the capsid protein NoLS (CHIKV-NoLS) attenuated replication in mammalian and mosquito cells, producing a small-plaque phenotype. Attenuation of CHIKV-NoLS is likely due to disruption of the viral replication cycle downstream of viral RNA synthesis. In mice, CHIKV-NoLS infection caused no disease signs compared to wild-type CHIKV (CHIKV-WT)-infected mice; lack of disease signs correlated with significantly reduced viremia and decreased expression of proinflammatory factors. Mice immunized with CHIKV-NoLS, challenged with CHIKV-WT at 30 days postimmunization, develop no disease signs and no detectable viremia. Serum from CHIKV-NoLS-immunized mice is able to efficiently neutralize CHIKV infection in vitro. Additionally, CHIKV-NoLS-immunized mice challenged with the related alphavirus Ross River virus showed reduced early and peak viremia postchallenge, indicating a cross-protective effect. The high degree of CHIKV-NoLS attenuation may improve CHIKV antiviral and rational vaccine design. IMPORTANCE CHIKV is a mosquito-borne pathogen capable of causing explosive epidemics of incapacitating joint pain affecting millions of people. After a series of major outbreaks over the last 10 years, CHIKV and its mosquito vectors have been able to expand their range extensively, now making CHIKV a human pathogen of global importance. With no licensed vaccine or antiviral therapy for the treatment of CHIKV disease, there is a growing need to understand the molecular determinants of viral pathogenesis. These studies identify a previously uncharacterized nucleolar localization sequence (NoLS) in CHIKV capsid protein, begin a functional analysis of site-directed mutants of the capsid protein NoLS, and examine the effect of the NoLS mutation on CHIKV pathogenesis in vivo and its potential to influence CHIKV vaccine design. A better understanding of the pathobiology of CHIKV disease will aid the development of effective therapeutic strategies.
format	article
author	Adam Taylor Xiang Liu Ali Zaid Lucas Y. H. Goh Jody Hobson-Peters Roy A. Hall Andres Merits Suresh Mahalingam
author_facet	Adam Taylor Xiang Liu Ali Zaid Lucas Y. H. Goh Jody Hobson-Peters Roy A. Hall Andres Merits Suresh Mahalingam
author_sort	Adam Taylor
title	Mutation of the N-Terminal Region of Chikungunya Virus Capsid Protein: Implications for Vaccine Design
title_short	Mutation of the N-Terminal Region of Chikungunya Virus Capsid Protein: Implications for Vaccine Design
title_full	Mutation of the N-Terminal Region of Chikungunya Virus Capsid Protein: Implications for Vaccine Design
title_fullStr	Mutation of the N-Terminal Region of Chikungunya Virus Capsid Protein: Implications for Vaccine Design
title_full_unstemmed	Mutation of the N-Terminal Region of Chikungunya Virus Capsid Protein: Implications for Vaccine Design
title_sort	mutation of the n-terminal region of chikungunya virus capsid protein: implications for vaccine design
publisher	American Society for Microbiology
publishDate	2017
url	https://doaj.org/article/81b757c4f7e64d60899db9b431272658
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Mutation of the N-Terminal Region of Chikungunya Virus Capsid Protein: Implications for Vaccine Design

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