VCP/p97 Is a Proviral Host Factor for Replication of Chikungunya Virus and Other Alphaviruses.

Guillaume Carissimo,Yi-Hao Chan,Farhana Abu Bakar,Andres Merits,Tze-Kwang Chua,Age Utt,Lisa F P Ng

doi:10.3389/fmicb.2019.02236

Abstract

The evolutionarily conserved AAA+ ATPase valosin-containing protein (VCP) was previously shown to be a proviral host factor for several viruses from different viral families such as Flaviviridae, Picornaviridae, and Herpesviridae. VCP was shown to affect trafficking of Sindbis virus receptor and functions as a component of Semliki Forest virus (SFV) replicase compartment. However, the role of this cellular protein was not evaluated during replication of alphaviruses including chikungunya virus (CHIKV). Using siRNA, chemical inhibitors, and trans-replication assays, we show here that VCP is a proviral factor involved in the replication of CHIKV. Immunofluorescence assays confirmed that VCP co-localized with non-structural replicase proteins but not with dsRNA foci possibly due to VCP epitope unavailability. VCP pro-viral role is also observed with other alphaviruses such as o’nyong’nyong virus (ONNV) and SFV in different human cell lines. VCP proviral roles on several viral families now extend to replication of alphaviruses CHIKV and ONNV, emphasizing the pivotal role of VCP in virus–host interaction biology.

Highlights

The valosin-containing protein (VCP), named p97, is a member of the hexameric AAA+ ATPase family and is highly conserved across all domains of life (Erzberger and Berger, 2006; Barthelme and Sauer, 2016)
In order to assess if VCP has a role during chikungunya virus (CHIKV) infection, transfection of a mix of three siRNAs targeting VCP followed by infection with CHIKV-expressing Gaussia luciferase (Gluc) inserted between non-structural and structural coding regions, as an indirect marker of viral replication, was performed
VCP knockdown significantly reduced viral infection (Figures 1D,E). These results suggest a proviral role of VCP during CHIKV infection

Summary

Introduction

The valosin-containing protein (VCP), named p97, is a member of the hexameric AAA+ ATPase family and is highly conserved across all domains of life (Erzberger and Berger, 2006; Barthelme and Sauer, 2016). Valosin-containing protein has been reported to be a pro- or anti-viral host factor for several viruses, such as picornaviruses (Arita et al, 2012; Wu et al, 2016; Wang et al, 2017), flaviviruses (Yi et al, 2016; Phongphaew et al, 2017; Yi and Yuan, 2017), coronaviruses (Wong et al, 2015), an herpesvirus (Lin et al, 2017), a phlebovirus (Brahms et al, 2017), and even an insect nucleopolyhedrovirus (Lyupina et al, 2018). VCP have been described as an important host factor for several flaviviruses (ssRNA+) West Nile virus replication (Phongphaew et al, 2017), as well as a component of Hepatitis C virus (HCV) and shown to prevent HCV replicase aggregation (Yi et al, 2016; Yi and Yuan, 2017)

Methods

Results

Conclusion