State Key Laboratory of Developmental Biology of Freshwater Fish, College of Life Science, Hunan Normal University, Changsha, 410081, China.
State Key Laboratory of Developmental Biology of Freshwater Fish, College of Life Science, Hunan Normal University, Changsha, 410081, China.
Fish Shellfish Immunol. 2017 Nov;70:13-24. doi: 10.1016/j.fsi.2017.08.037. Epub 2017 Aug 30.
Stimulator of interferon genes (STING) is a central and multifaceted mediator in the innate immune response of higher vertebrates. To explore its role in teleost fish, the STING homolog of black carp (Mylopharyngodon piceus) (bcSTING) has been cloned and characterized in this paper. bcSTING transcription in Mylopharyngodon piceus fin (MPF) cells increased remarkably in response to GCRV and SVCV infection, or poly (I:C) stimulation. bcSTING migrated around 42 KDa in immunoblot assay and was identified as a cytosolic protein locating on ER majorly through immunofluorescence staining. Under condition of SVCV/GCRV infection or poly (I:C) stimulation, the subcellular distribution of bcSTING majorly displayed on mitochondria, which overlapped with that of bcMAVS. HA-bcSTING instead of bcSTING-HA presented strong IFN-inducing activity in reporter assay and antiviral ability against both SVCV and GCRV in plaque assay. Site mutation of serine (S) on C-terminus of bcSTING demonstrated that both S371 and S379 were crucial for its mediated signaling. Taken together, our study support the conclusion that bcSTING plays an important role in host innate immune defense against RNA virus such as SVCV and GCRV, in which its C-terminus functions crucially.
干扰素基因刺激蛋白（STING）是高等脊椎动物先天免疫反应的核心和多方面的介质。为了探索其在硬骨鱼类中的作用，本文克隆并鉴定了草鱼（Mylopharyngodon piceus）的 STING 同源物（bcSTING）。bcSTING 在草鱼鳍细胞（MPF）中的转录在 GCRV 和 SVCV 感染或 poly（I:C）刺激时显著增加。免疫印迹分析表明，bcSTING 迁移约 42 kDa，被鉴定为主要位于内质网上的细胞质蛋白，通过免疫荧光染色进一步证实。在 SVCV/GCRV 感染或 poly（I:C）刺激条件下，bcSTING 的亚细胞分布主要显示在线粒体上，与 bcMAVS 重叠。HA-bcSTING 而不是 bcSTING-HA 在报告基因测定中表现出强烈的 IFN 诱导活性，并在斑块测定中对 SVCV 和 GCRV 具有抗病毒能力。bcSTING C 末端丝氨酸（S）的位点突变表明 S371 和 S379 对其介导的信号通路都至关重要。综上所述，我们的研究支持以下结论：bcSTING 在宿主对 RNA 病毒（如 SVCV 和 GCRV）的先天免疫防御中发挥重要作用，其 C 末端在其中起着关键作用。
