天然免疫是机体抵御病毒入侵的第一道防线，但是过激的天然免疫反应会导致一些疾病的产生。因此，对于天然免疫负向调控子和负向调控机制的研究是近年来免疫学领域的热点。PIAS蛋白是重要的负调控子，在免疫相关信号通路中发挥重要的调节作用。迄今为止，鱼类中PIAS1功能报道较少。我们前期工作中成功克隆了石斑鱼PIAS1基因，过量表达PIAS1可抑制病毒诱导的NF-κB，ISRE和IFN-β启动子的激活。本项目拟在此基础上，利用基因克隆、荧光定量PCR、免疫荧光、免疫共沉淀、免疫印迹、报告基因、点突变、基因过表达/敲降等技术，开展如下研究：1）PIAS1表达模式、细胞定位和SUMO E3 ligases活性；2）PIAS1调控NF-κB激活的作用机理；3）PIAS1调控病毒诱导IRF3激活的作用机理。研究结果将为阐明鱼类细胞抗病毒免疫反应的分子机制奠定一定理论基础，也为鱼类病毒病防控提供潜在的治疗靶点。

Though innate immunity is the first line of host defense against invading viruses，excessive innate immune response give rise to the immunopathological alterations. Thus, the molecular mechanism of negative regulators and regulation of the innate immunity is becoming one of the research hotspots in recent years. The protein inhibitor of activated STAT (PIAS) protein family is one of the most important negative regulators, and has many important functions, especially in the regulation of immune related signaling pathway. But so far, little related information of PIAS1 has been reported in fish. In our previous research, a PIAS1 sequence from grouper (EcPIAS1) was identified. Overexpression of EcPIAS1 inhibited NF-κB, ISRE and IFN-β activation. In this project, the mechanisms of virus-induced expression of type I interferon by PIAS1 in grouper (Epinephelus coioides) will be thoroughly studied by using molecular and cellular techniques, including gene cloning, real-time quantitative PCR, immunofluorescence, Co-Immunoprecipitation, western blot, luciferase reporter assay, single base substitution and gene overexpression/silencing. This investigation will focus on: 1) The expression patterns, intracellular localization and SUMO E3 ligases activities of EcPIAS1. 2) The regulations of NF-κB activation by EcPIAS1. 3) The regulations of virus-induced IRF3 activation by EcPIAS1. The finding will contribute to the elucidation of molecular mechanisms of fish cellular antiviral responses, and provide potential therapeutic targets for fish virus disease prevention and control.