Characterization of nonstructural protein 3 of a neurovirulent Japanese encephalitis virus strain isolated from a pig

Xufang Deng,Donghua Shao,Guangzhi Tong,Yafeng Qiu,Xiaodu Wang,Zixue Shi,Shuqing Li,Jianchao Wei,Zhiyong Ma

doi:10.1186/1743-422x-8-209

Xufang Deng, Donghua Shao + Show 7 more

Open Access

https://doi.org/10.1186/1743-422x-8-209

Copy DOI

Abstract

BackgroundJapanese encephalitis virus (JEV), as a re-emerging virus that causes 10,000-15,000 human deaths from encephalitis in the world each year, has had a significant impact on public health. Pigs are the natural reservoirs of JEV and play an important role in the amplification, dispersal and epidemiology of JEV. The nonstructural protein 3 (NS3) of JEV possesses enzymatic activities of serine protease, helicase and nucleoside 5'-triphosphatase, and plays important roles in viral replication and pathogenesis.ResultsWe characterized the NS3 protein of a neurovirulent strain of JEV (SH-JEV01) isolated from a field-infected pig. The NS3 gene of the JEV SH-JEV01 strain is 1857 bp in length and encodes protein of approximately 72 kDa with 99% amino acid sequence identity to that of the representative immunotype strain JaGAr 01. The NS3 protein was detectable 12 h post-infection in a mouse neuroblastoma cell line, Neuro-2a, and was distributed in the cytoplasm of cells infected with the SH-JEV01 strain of JEV. In the brain of mice infected with the SH-JEV01 strain of JEV, NS3 was detected in the cytoplasm of neuronal cells, including pyramidal neurons of the cerebrum, granule cells, small cells and Purkinje cells of the cerebellum.ConclusionsThe NS3 protein of a neurovirulent strain of JEV isolated from a pig was characterized. It is an approximately 72 kDa protein and distributed in the cytoplasm of infected cells. The Purkinje cell of the cerebellum is one of the target cells of JEV infection. Our data should provide some basic information for the study of the role of NS3 in the pathogenesis of JEV and the immune response.

Highlights

Japanese encephalitis virus (JEV), as a re-emerging virus that causes 10,000-15,000 human deaths from encephalitis in the world each year, has had a significant impact on public health
We characterized the nonstructural protein 3 (NS3) protein of a neurovirulent strain of JEV (SH-JEV01) isolated from a field-infected pig, because NS3 is a multifunctional protein that plays important roles in viral replication, as described above, and in the host immune response and pathogenesis
Cloning and expression of the NS3 gene The gene encoding the full-length NS3 protein of JEV SH-JEV01 strain was amplified from JEV-infected cells by reverse transcription-polymerase chain reaction (RTPCR)

Summary

Introduction

Japanese encephalitis virus (JEV), as a re-emerging virus that causes 10,000-15,000 human deaths from encephalitis in the world each year, has had a significant impact on public health. The nonstructural protein 3 (NS3) of JEV possesses enzymatic activities of serine protease, helicase and nucleoside 5’triphosphatase, and plays important roles in viral replication and pathogenesis. The nonstructural protein 3 (NS3) of JEV is a multifunctional protein of 619 amino acid residues. It possesses enzymatic activities of serine protease, helicase and nucleoside 5’-triphosphatase, and plays important roles in the processing of the viral precursor polyprotein and the replication of viral genomic RNA [3]. NS3 is localized mainly at the JEV-induced convoluted membrane, a membrane vesicle structure, which has been proposed to originate from rough endoplasmic reticulum, Golgi apparatus or the trans-Golgi network, and serves as a reservoir for viral proteins during virus assembly [6]. NS3 has been considered to be a candidate target molecule for development of novel potent therapeutic substances [7]

Methods

Results

Discussion

Conclusion