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.

中文翻译：

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Y盒结合蛋白3（YBX3）通过与病毒核糖核蛋白复合物相互作用并影响其功能来限制甲型流感病毒。

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转录和复制。vRNP复合体与宿主因子之间的相互作用在病毒复制，致病性和物种嗜性中起重要作用。在这项研究中，使用Strep-tag亲和纯化与质谱联用来鉴定与感染人类细胞中IAV vRNP复合体相互作用的宿主因子。我们从HEK 293T细胞中纯化了vRNP复合物，该细胞感染了含有Strep-tag PB2亚基的重组小鼠适应IAV（A / Chicken / Hubei / 489/2004），并鉴定了Y盒结合蛋白3（YBX3）作为负调控因子。 IAV复制。YBX3的过表达抑制病毒复制，病毒蛋白表达和vRNA合成。反过来，YBX3的RNAi抑制导致病毒生长速率显着提高。此外，敲低YBX3可以增加被感染细胞中NP的核积累和病毒初级转录。我们的结果表明，YBX3通过与vRNP复合体相互作用并随后阻碍其功能来限制IAV复制。