Coxsackievirus B3 Responds to Polyamine Depletion via Enhancement of 2A and 3C Protease Activity

Polyamines are small positively-charged molecules abundant in eukaryotic cells that are crucial to RNA virus replication. In eukaryotic cells, polyamines facilitate processes such as transcription, translation, and DNA replication, and viruses similarly rely on polyamines to facilitate transcription...

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Main Authors: Courtney N. Dial, Patrick M. Tate, Thomas M. Kicmal, Bryan C. Mounce
Format: Article
Language:English
Published: MDPI AG 2019-04-01
Series:Viruses
Subjects:
Online Access:https://www.mdpi.com/1999-4915/11/5/403
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author Courtney N. Dial
Patrick M. Tate
Thomas M. Kicmal
Bryan C. Mounce
author_facet Courtney N. Dial
Patrick M. Tate
Thomas M. Kicmal
Bryan C. Mounce
author_sort Courtney N. Dial
collection DOAJ
description Polyamines are small positively-charged molecules abundant in eukaryotic cells that are crucial to RNA virus replication. In eukaryotic cells, polyamines facilitate processes such as transcription, translation, and DNA replication, and viruses similarly rely on polyamines to facilitate transcription and translation. Whether polyamines function at additional stages in viral replication remains poorly understood. Picornaviruses, including Coxsackievirus B3 (CVB3), are sensitive to polyamine depletion both in vitro and in vivo; however, precisely how polyamine function in picornavirus infection has not been described. Here, we describe CVB3 mutants that arise with passage in polyamine-depleted conditions. We observe mutations in the 2A and 3C proteases, and we find that these mutant proteases confer resistance to polyamine depletion. Using a split luciferase reporter system to measure protease activity, we determined that polyamines facilitate viral protease activity. We further observe that the 2A and 3C protease mutations enhance reporter protease activity in polyamine-depleted conditions. Finally, we find that these mutations promote cleavage of cellular eIF4G during infection of polyamine-depleted cells. In sum, our results suggest that polyamines are crucial to protease function during picornavirus infection. Further, these data highlight viral proteases as potential antiviral targets and highlight how CVB3 may overcome polyamine-depleting antiviral therapies.
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spelling doaj.art-1f2853ace6f44a5aa62349ed09f3f8c72022-12-21T20:13:36ZengMDPI AGViruses1999-49152019-04-0111540310.3390/v11050403v11050403Coxsackievirus B3 Responds to Polyamine Depletion via Enhancement of 2A and 3C Protease ActivityCourtney N. Dial0Patrick M. Tate1Thomas M. Kicmal2Bryan C. Mounce3Department of Microbiology and Immunology, Stritch School of Medicine, Loyola University Chicago, Maywood, IL 60153, USADepartment of Microbiology and Immunology, Stritch School of Medicine, Loyola University Chicago, Maywood, IL 60153, USADepartment of Microbiology and Immunology, Stritch School of Medicine, Loyola University Chicago, Maywood, IL 60153, USADepartment of Microbiology and Immunology, Stritch School of Medicine, Loyola University Chicago, Maywood, IL 60153, USAPolyamines are small positively-charged molecules abundant in eukaryotic cells that are crucial to RNA virus replication. In eukaryotic cells, polyamines facilitate processes such as transcription, translation, and DNA replication, and viruses similarly rely on polyamines to facilitate transcription and translation. Whether polyamines function at additional stages in viral replication remains poorly understood. Picornaviruses, including Coxsackievirus B3 (CVB3), are sensitive to polyamine depletion both in vitro and in vivo; however, precisely how polyamine function in picornavirus infection has not been described. Here, we describe CVB3 mutants that arise with passage in polyamine-depleted conditions. We observe mutations in the 2A and 3C proteases, and we find that these mutant proteases confer resistance to polyamine depletion. Using a split luciferase reporter system to measure protease activity, we determined that polyamines facilitate viral protease activity. We further observe that the 2A and 3C protease mutations enhance reporter protease activity in polyamine-depleted conditions. Finally, we find that these mutations promote cleavage of cellular eIF4G during infection of polyamine-depleted cells. In sum, our results suggest that polyamines are crucial to protease function during picornavirus infection. Further, these data highlight viral proteases as potential antiviral targets and highlight how CVB3 may overcome polyamine-depleting antiviral therapies.https://www.mdpi.com/1999-4915/11/5/403polyaminesCoxsackievirus B3protease
spellingShingle Courtney N. Dial
Patrick M. Tate
Thomas M. Kicmal
Bryan C. Mounce
Coxsackievirus B3 Responds to Polyamine Depletion via Enhancement of 2A and 3C Protease Activity
Viruses
polyamines
Coxsackievirus B3
protease
title Coxsackievirus B3 Responds to Polyamine Depletion via Enhancement of 2A and 3C Protease Activity
title_full Coxsackievirus B3 Responds to Polyamine Depletion via Enhancement of 2A and 3C Protease Activity
title_fullStr Coxsackievirus B3 Responds to Polyamine Depletion via Enhancement of 2A and 3C Protease Activity
title_full_unstemmed Coxsackievirus B3 Responds to Polyamine Depletion via Enhancement of 2A and 3C Protease Activity
title_short Coxsackievirus B3 Responds to Polyamine Depletion via Enhancement of 2A and 3C Protease Activity
title_sort coxsackievirus b3 responds to polyamine depletion via enhancement of 2a and 3c protease activity
topic polyamines
Coxsackievirus B3
protease
url https://www.mdpi.com/1999-4915/11/5/403
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