Shanghai Key Laboratory of Veterinary Biotechnology, Key Laboratory of Urban Agriculture (South), School of Agriculture and Biology, Shanghai Jiao Tong University, Ministry of Agriculture, Shanghai, China.
Front Immunol. 2019 Apr 17;10:822. doi: 10.3389/fimmu.2019.00822. eCollection 2019.
Asp-Glu-Ala-Asp (DEAD)-box polypeptide 3 X-linked (DDX3X) is an ATP-dependent RNA helicase, In addition to involvement of eukaryotic gene expression regulation, mammalian DDX3X has recently been found to regulate IFN-β production via the adaptor MAVS mediated cascade signaling. In our studies, we demonstrated that chicken DDX3X (chDDX3X) is also involved in the IFN-β regulation, and demonstrated that chDDX3X regulated IFN-β via an essential adaptor chicken stimulator of IFN genes (chSTING). We found that chDDX3X overexpression in DF-1 cells induced expression of IFN-β and inhibited avian influenza virus (AIV) or Newcastle disease virus (NDV) replication. Knockdown of chDDX3X decreased the production of IFN-β induced by RNA analog polyinosinic-polycytidylic acid and increased viral yield. Furthermore, chDDX3X was identified as a potential chSTING-interacting protein by co-immunoprecipitation (Co-IP) and liquid chromatography-tandem mass spectrometry (LC-MS/MS). And exogenous Co-IP in transfected cells with or without virus-stimulations further confirmed the interaction between chDDX3X and chSTING. With the gene overexpression and RNA interference studies, the chDDX3X was confirmed to be located upstream of chSTING and activate IFN-β via the chSTING-chTBK1-chIRF7-IFN-β signaling axis. In brief, our results suggest that chDDX3X is an important IFN-β mediator and is involved in RNA- and RNA virus-mediated chDDX3X-chSTING-IFN-β signaling pathway.
X 连锁的天冬氨酸-谷氨酸-丙氨酸-天冬氨酸（DEAD）框多肽 3 （DDX3X）是一种 ATP 依赖性 RNA 解旋酶，除了参与真核基因表达调控外，哺乳动物 DDX3X 最近还被发现通过衔接子 MAVS 介导的级联信号调节 IFN-β 的产生。在我们的研究中，我们证明鸡 DDX3X（chDDX3X）也参与 IFN-β 的调节，并证明 chDDX3X 通过必需的衔接子鸡干扰素基因刺激物（chSTING）来调节 IFN-β。我们发现，DF-1 细胞中 chDDX3X 的过表达诱导了 IFN-β 的表达，并抑制了禽流感病毒（AIV）或新城疫病毒（NDV）的复制。chDDX3X 的敲低降低了 RNA 类似物聚肌胞诱导的 IFN-β 的产生，并增加了病毒产量。此外，通过免疫共沉淀（Co-IP）和液相色谱-串联质谱（LC-MS/MS）鉴定 chDDX3X 是潜在的 chSTING 相互作用蛋白。并且转染细胞的外源 Co-IP 无论是在有无病毒刺激的情况下，都进一步证实了 chDDX3X 与 chSTING 之间的相互作用。通过基因过表达和 RNA 干扰研究，证实 chDDX3X 位于 chSTING 的上游，并通过 chSTING-chTBK1-chIRF7-IFN-β 信号轴激活 IFN-β。简而言之，我们的结果表明 chDDX3X 是一种重要的 IFN-β 介体，参与了 RNA 和 RNA 病毒介导的 chDDX3X-chSTING-IFN-β 信号通路。
