Function of Host Protein Staufen1 in Rabies Virus Replication.

Gaowen Liu,Ruixian Xu,Xueshan Xia,Yuzhu Song,Ming Yang,Qinqin Han,Jinyang Zhang,Congjie Chen,Binghui Wang

doi:10.3390/v13081426

Abstract

Rabies virus is a highly neurophilic negative-strand RNA virus with high lethality and remains a huge public health problem in developing countries to date. The double-stranded RNA-binding protein Staufen1 (STAU1) has multiple functions in RNA virus replication, transcription, and translation. However, its function in RABV infection and its mechanism of action are not clear. In this study, we investigated the role of host factor STAU1 in RABV infection of SH-SY-5Y cells. Immunofluorescence, TCID50 titers, confocal microscopy, quantitative real-time PCR and Western blotting were carried out to determine the molecular function and subcellular distribution of STAU1 in these cell lines. Expression of STAU1 in SH-SY-5Y cells was down-regulated by RNA interference or up-regulated by transfection of eukaryotic expression vectors. The results showed that N proficiently colocalized with STAU1 in SH-SY-5Y at 36 h post-infection, and the expression level of STAU1 was also proportional to the time of infection. Down-regulation of STAU1 expression increased the number of Negri body-like structures, enhanced viral replication, and a caused 10-fold increase in viral titers. Meanwhile, N protein and G protein mRNA levels also accumulated gradually with increasing infection time, which implied that STAU1 inhibited rabies virus infection of SH-SY-5Y cells in vitro. In conclusion, our results provide important clues for the detailed replication mechanism of rabies virus and the discovery of therapeutic targets.

Highlights

Rabies is an important zoonotic infectious disease caused by rabies virus (RABV), with a mortality rate of almost 100% [1]
During RABV infection of cells, a large number of host proteins are recruited into Negri bodies (NBs), such as CCTγ, CCTα, and Prefoldin 1, which have an impact on virus replication
To determine whether STAU1 is recruited into RABV Negri bodies (NBs) upon viral infection, we infected SH-SY-5Y cells with the RABV HEP-Flury strain for 36 h and visualized the localization of endogenous

Summary

Introduction

Rabies is an important zoonotic infectious disease caused by rabies virus (RABV), with a mortality rate of almost 100% [1]. The N protein participates in the formation of the viral nuclear capsid and binds genomic RNA to form the ribonucleoprotein complex (RNP). This allows the cellular nuclease P protein to bind to viral genomic RNA and L protein in RNP by bridging the N protein [8]. The G protein is the only surface protein of the viral particle that allows RABV to enter the nervous system from peripheral sites through interaction with host cell receptors and is a major contributor to viral pathogenicity [10]. The L protein is the largest protein in the virus and has multiple enzymatic activities in the synthesis and processing of viral RNA, performing the function of an RNA-dependent RNA polymerase [11]

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Results

Conclusion