日本鳗鲡两个RIG-I介导的免疫识别及对I型IFN抗病毒免疫应答调控作用的研究

视黄酸诱导基因I（Retinoic acid inducible gene I, RIG-I）是位于细胞质中的模式识别受体，可识别胞浆中的病毒RNA进而活化下游信号通路，启动I型干扰素和促炎症因子的表达。在前期的研究中，我们发现日本鳗鲡中存在两个RIG-I基因，且两者分别定位于细胞质与细胞核。目前有关鱼类RIG-I介导的免疫识别和信号转导过程尚不清楚，关于细胞核内的免疫识别和应答机制更是知之甚少。因此，本项目拟利用RNase酶切印迹、RIP-seq、免疫共沉淀等方法探究日本鳗鲡细胞核、细胞质RIG-I识别配体的异同及活化的机制；结合定点突变、免疫印迹等方法阐释核内RIG-I入核转运的机理；利用报告基因、差异表达谱分析等手段解析两者介导的信号转导通路。本项目的完成将首次解析鱼类细胞核内免疫识别和调节机制，研究结果将有助于深入了解鱼类的免疫抗病机理，为宿主与病毒相互作用机制提供更多创新性观点。

Retinoic acid inducible gene I（RIG-I）has always been regarded as cytosolic pattern recognition receptor that recognizes viral RNA and initiates signaling cascades, leading to the induction of antiviral immune response by producing pro-inflammatory cytokines and type I interferon. In our previous study, two RIG-I-encoding genes were identified in Japanese eel (Anguilla japonica), being distributed in the cytoplasm and nucleus respectively. However, much less is known about the molecular mechanism of RIG-I-mediated immune response in fish, especially regarding pathways that link the nuclear immune recognition with activation of antiviral immune response. This proposed research is thus designed to reveal the difference in ligand specificities between the two eel RIG-I genes. Then, the structural basis and molecular mechanism of the RIG-I-mediated immune recognition and the nuclear import mechanism of nuclear-resident RIG-I will be further deciphered. The effect of the cytoplasm-resident and nuclear-resident RIG-I on antiviral immunity will be evaluated eventually by examining their ligand recognition, signaling pathways and regulation of downstream genes. It is believed that this proposed research will for the first time provide the mechanistic insight into nuclear viral RNA sensing paradigm regulation mechanism in lower vertebrate, offering new perspectives in our knowledge of antiviral immune response in fish, being thus significantly important in understanding the immune response of fish.