State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, PR China.
J Gen Virol. 2020 Apr;101(4):385-398. doi: 10.1099/jgv.0.001390.
The influenza A virus (IAV) ribonucleoprotein (vRNP) complex consists of polymerase subunits, nucleoprotein (NP) and viral RNA and is responsible for RNA transcription and replication. Interactions between the vRNP complex and host factors play important roles in virus replication, pathogenicity and species tropism. In this study, Strep-tag affinity purification coupled with mass spectrometry was used to identify host factors that interact with IAV vRNP complex in infected human cells. We purified vRNP complex from HEK 293T cells infected with a recombinant mouse-adapted IAV (A/Chicken/Hubei/489/2004) containing a Strep-tag PB2 subunit and identified Y-box-binding protein 3 (YBX3) as a negative regulator of IAV replication. Overexpression of YBX3 inhibited the virus replication, viral protein expression and vRNA synthesis. Conversely, RNAi knockdown of YBX3 resulted in significantly increased virus growth rate. Furthermore, knockdown of YBX3 augmented the nuclear accumulation of NP and viral primary transcription in infected cells. Our results suggest that YBX3 restricts IAV replication by interacting with vRNP complex and subsequently imparing its function.
甲型流感病毒（IAV）核糖核蛋白（vRNP）复合物由聚合酶亚基、核蛋白（NP）和病毒 RNA 组成，负责 RNA 的转录和复制。vRNP 复合物与宿主因子之间的相互作用对病毒复制、致病性和物种嗜性起着重要作用。在这项研究中，使用链霉亲和素亲和纯化结合质谱法来鉴定感染的人细胞中与 IAV vRNP 复合物相互作用的宿主因子。我们从感染了含有链霉亲和素 PB2 亚基的重组鼠适应型 IAV（A/Chicken/Hubei/489/2004）的 HEK 293T 细胞中纯化 vRNP 复合物，并鉴定出 Y 盒结合蛋白 3（YBX3）是 IAV 复制的负调控因子。YBX3 的过表达抑制了病毒复制、病毒蛋白表达和 vRNA 合成。相反，YBX3 的 RNAi 敲低导致病毒生长速度显著增加。此外，YBX3 的敲低增加了感染细胞中 NP 的核积累和病毒初级转录。我们的结果表明，YBX3 通过与 vRNP 复合物相互作用并随后损害其功能来限制 IAV 的复制。
