Institut de Recherche en Immunologie et en Cancérologie, Université de Montréal, C.P. 6128, Succursale Centre-ville, Montréal, Québec H3C 3J7, Canada.
J Virol. 2011 Nov;85(21):11022-37. doi: 10.1128/JVI.00719-11. Epub 2011 Aug 17.
The hepatitis C virus (HCV) NS3/4A protein has several essential roles in the virus life cycle, most probably through dynamic interactions with host factors. To discover cellular cofactors that are co-opted by HCV for its replication, we elucidated the NS3/4A interactome using mass spectrometry and identified Y-box-binding protein 1 (YB-1) as an interacting partner of NS3/4A protein and HCV genomic RNA. Importantly, silencing YB-1 expression decreased viral RNA replication and severely impaired the propagation of the infectious HCV molecular clone JFH-1. Immunofluorescence studies further revealed a drastic HCV-dependent redistribution of YB-1 to the surface of the lipid droplets, an important organelle for HCV assembly. Core and NS3 protein-dependent polyprotein maturation were shown to be required for YB-1 relocalization. Unexpectedly, YB-1 knockdown cells showed the increased production of viral infectious particles while HCV RNA replication was impaired. Our data support that HCV hijacks YB-1-containing ribonucleoparticles and that YB-1-NS3/4A-HCV RNA complexes regulate the equilibrium between HCV RNA replication and viral particle production.
丙型肝炎病毒（HCV）NS3/4A 蛋白在病毒生命周期中具有几个重要作用，很可能通过与宿主因子的动态相互作用来实现。为了发现 HCV 用于复制的细胞辅助因子，我们使用质谱法阐明了 NS3/4A 相互作用组，并鉴定出 Y 盒结合蛋白 1（YB-1）是 NS3/4A 蛋白和 HCV 基因组 RNA 的相互作用伙伴。重要的是，沉默 YB-1 的表达会降低病毒 RNA 的复制，并严重损害传染性 HCV 分子克隆 JFH-1 的传播。免疫荧光研究进一步揭示了 HCV 依赖性 YB-1 向脂质滴表面的剧烈重分布，脂质滴是 HCV 组装的重要细胞器。核心和 NS3 蛋白依赖性多蛋白成熟被证明是 YB-1 再定位所必需的。出乎意料的是，YB-1 敲低细胞显示出增加的病毒感染性颗粒的产生，而 HCV RNA 复制受到损害。我们的数据支持 HCV 劫持含有 YB-1 的核糖核蛋白体，并且 YB-1-NS3/4A-HCV RNA 复合物调节 HCV RNA 复制和病毒颗粒产生之间的平衡。
