Role of PDZ-binding motif from West Nile virus NS5 protein on viral replication

Emilie Giraud,Célia Caillet-Saguy,Cécile Khou,Yves Jacob,Chloé Otero Del Val,Nathalie Pardigon,Nicolas Wolff,Nada Zehrouni,Joël Caillet

doi:10.1038/s41598-021-82751-x

Abstract

West Nile virus (WNV) is a Flavivirus, which can cause febrile illness in humans that may progress to encephalitis. Like any other obligate intracellular pathogens, Flaviviruses hijack cellular protein functions as a strategy for sustaining their life cycle. Many cellular proteins display globular domain known as PDZ domain that interacts with PDZ-Binding Motifs (PBM) identified in many viral proteins. Thus, cellular PDZ-containing proteins are common targets during viral infection. The non-structural protein 5 (NS5) from WNV provides both RNA cap methyltransferase and RNA polymerase activities and is involved in viral replication but its interactions with host proteins remain poorly known. In this study, we demonstrate that the C-terminal PBM of WNV NS5 recognizes several human PDZ-containing proteins using both in vitro and in cellulo high-throughput methods. Furthermore, we constructed and assayed in cell culture WNV replicons where the PBM within NS5 was mutated. Our results demonstrate that the PBM of WNV NS5 is important in WNV replication. Moreover, we show that knockdown of the PDZ-containing proteins TJP1, PARD3, ARHGAP21 or SHANK2 results in the decrease of WNV replication in cells. Altogether, our data reveal that interactions between the PBM of NS5 and PDZ-containing proteins affect West Nile virus replication.

Highlights

West Nile virus (WNV) is a Flavivirus, which can cause febrile illness in humans that may progress to encephalitis
As non-structural protein 5 (NS5) of Flaviviruses provides RNA cap MTase and RNA-dependent RNA polymerase (RdRp) activities, we focused our efforts to determine whether the PDZ-Binding Motifs (PBM) of WNV NS5 affects virus replication
We constructed a negative control replicon coding for an inactive RdRp with a single mutation in the replication “pocket” on WNV NS5 (Rep-IS98-Gluc-GVD) and a replicon with a deletion of the three residues -TVL identified as the PBM motif (Rep-IS98-Gluc-∆PBM) (Fig. 1A)

Summary

Introduction

West Nile virus (WNV) is a Flavivirus, which can cause febrile illness in humans that may progress to encephalitis. The non-structural protein 5 (NS5) from WNV provides both RNA cap methyltransferase and RNA polymerase activities and is involved in viral replication but its interactions with host proteins remain poorly known. Internal and C-terminal PBMs are present in the non-structural (NS) proteins NS5 of Flaviviruses which provides the RNA cap methyltransferase (MTase) and the RNA-dependent RNA polymerase (RdRp) activities as well as suppression of type 1 interferon signaling[8]. Their association with PDZ-containing proteins has been demonstrated for TBEV and dengue virus (DV)[9,10]. It is highly probable that the PBM of WNV NS5 protein plays a role during infection, in particular during replication by interacting with host partners

Methods

Results

Conclusion