Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan.
Department of Virology, Institute of Tropical Medicine (NEKKEN), Nagasaki University, Nagasaki, Japan.
J Gen Virol. 2014 Feb;95(Pt 2):373-383. doi: 10.1099/vir.0.057968-0.
Japanese encephalitis virus (JEV), which belongs to the genus Flavivirus of the family Flaviviridae, is a leading cause of meningo-encephalitis in Asian countries. The flavivirus non-structural protein 1 (NS1) plays a role in virus replication and in the elicitation of an immune response. The NS1' protein found among the members of the JEV subgroup is an extended form of NS1 and is generated by a -1 ribosomal frameshift. This protein is known to be involved in viral pathogenicity; however, its specific function is still unknown. Here, we describe an investigation of the molecular function of NS1' protein through the production of JEV NS1'-expressing and -non-expressing clones and their infection of avian and mammalian cells. Efficient NS1' protein expression was observed in avian cells and was found to facilitate JEV production in both avian cultured cells and embryonated chicken eggs. NS1' protein was observed to co-localize with NS5 protein and resulted in increased viral RNA levels in avian cells. These findings clearly indicate that NS1' enhances the production of JEV in avian cells and may facilitate the amplification/maintenance role of birds in the virus transmission cycle in nature.
日本脑炎病毒（JEV）属于黄病毒科黄病毒属，是亚洲国家脑膜脑炎的主要病因。黄病毒非结构蛋白 1（NS1）在病毒复制和免疫应答中发挥作用。在 JEV 亚群成员中发现的 NS1'蛋白是 NS1 的扩展形式，是通过 -1 核糖体移码产生的。该蛋白已知与病毒的致病性有关；然而，其具体功能尚不清楚。在这里，我们通过产生 JEV NS1'-表达和非表达克隆及其感染禽和哺乳动物细胞来描述对 NS1'蛋白的分子功能的研究。在禽细胞中观察到有效的 NS1'蛋白表达，并发现其促进了禽培养细胞和鸡胚中的 JEV 产生。观察到 NS1'蛋白与 NS5 蛋白共定位，并导致禽细胞中的病毒 RNA 水平增加。这些发现清楚地表明，NS1'增强了 JEV 在禽细胞中的产生，并可能有助于鸟类在自然界中病毒传播周期中的放大/维持作用。
