卵形鲳鲹干扰素调节因子IRF3亚家族的抗菌功能与机制研究

干扰素调节因子（IRFs）是调节干扰素及其相关基因的转录因子，其中IRF3和IRF7属IRF3亚家族，在机体抗病原免疫中具有重要作用。本项目针对目前鱼类IRF3亚家族抗病原功能研究主要集中于抗病毒而对其抗菌功能了解不足的现状，选择海南主要深水网箱养殖鱼类卵形鲳鲹为研究对象，在前期已克隆其IRF3和IRF7基因并初步确定其参与机体抗菌免疫的基础上，阐明不同病原菌刺激对IRF3和IRF7基因表达及调控规律、磷酸化水平和亚细胞定位的影响；以过量表达和干扰表达技术，确定细菌刺激后TLR通路及其关键接头蛋白对IRF3亚家族的诱导作用；以体外重组表达及定点突变等方法，揭示IRF3和IRF7不同功能区域对IFN、ISGs及其启动子活性的影响；确定IRF3亚家族的抗菌功能和机制。研究成果不仅有助于全面揭示鱼类IRF3亚家族的抗病原功能，对深入了解卵形鲳鲹免疫机制和建立安全高效疾病防控措施均有重要意义。

Interferon regulatory factors (IRFs) are crucial transcription factors in modulating transcription of IFN and IFN-stimulated genes (ISGs). IRF3 and IRF7 are two important members of the IRF3 subfamily, which are elicited on challenge to the host defense and are essential for mobilizing immune responses to pathogens. IRFs of IRF3 subfamily are primarily associated with host defense against viral infections. However, less is known about the bacterial activities of IRF3 and IRF7. Previously, we have cloned IRF3 and IRF7 from golden pompano (Trichinous ovatus) which are cultured in deep sea-cages in Hainan and demonstrated that they are involved in the process of host response to bacteria. In this study, the roles of G+ bacteria and G- bacteria in expression and regulatory, phosphorylation, and cytoplasmic-to-nuclear translocation of IRF3 and IRF7 will be explored; and overexpression and interference expression techniques are applied to identify which Toll-like receptor (TLR) pathway in response to bacterial stimulation and the IRF3 and IRF7 inducible property of its key adaptor proteins. Moreover, recombinant expression and mutational analysis method are used to elucidate that the main functional domain of IRF3 and IRF7 activates production of IFN that in turn triggers ISG transcription through increasing the activity of their promoter. Analysis the antibacterial activity and mechanism of golden pompano IRF3 and IRF7 not only helps to improve the current understanding of anti-pathogen function of IRF3 subfamily in fish, but also has important significance in understanding the immune system of golden pompano and providing safe and efficient measures for its protection against pathogen infection.