Department of Biomedical Sciences, Chang Gung University, TaoYuan, 33302, Taiwan.
Virol J. 2011 Mar 20;8:128. doi: 10.1186/1743-422X-8-128.
The serum-free medium from Japanese encephalitis virus (JEV) infected Baby Hamster Kidney-21 (BHK-21) cell cultures was analyzed by liquid chromatography tandem mass spectrometry (LC-MS) to identify host proteins that were secreted upon viral infection. Five proteins were identified, including the molecular chaperones Hsp90, GRP78, and Hsp70. The functional role of GRP78 in the JEV life cycle was then investigated. Co-migration of GRP78 with JEV particles in sucrose density gradients was observed and co-localization of viral E protein with GRP78 was detected by immunofluorescence analysis in vivo. Knockdown of GRP78 expression by siRNA did not effect viral RNA replication, but did impair mature viral production. Mature viruses that do not co-fractionate with GPR78 displayed a significant decrease in viral infectivity. Our results support the hypothesis that JEV co-opts host cell GPR78 for use in viral maturation and in subsequent cellular infections.
用液相色谱-串联质谱（LC-MS）分析乙型脑炎病毒（JEV）感染的仓鼠肾细胞（BHK-21）无血清培养基，以鉴定病毒感染时分泌的宿主蛋白。鉴定出 5 种蛋白，包括分子伴侣 Hsp90、GRP78 和 Hsp70。然后研究了 GRP78 在 JEV 生命周期中的功能作用。在蔗糖密度梯度中观察到 GRP78 与 JEV 颗粒共迁移，并通过免疫荧光分析在体内检测到病毒 E 蛋白与 GRP78 的共定位。siRNA 敲低 GRP78 表达不会影响病毒 RNA 复制，但会损害成熟病毒的产生。与 GPR78 不同分馏的成熟病毒的病毒感染力显著降低。我们的结果支持 JEV 劫持宿主细胞 GPR78 用于病毒成熟和随后的细胞感染的假说。
