两种大黄鱼Ｉ型干扰素的转录调控与功能研究

鱼类利用多种I型干扰素来调节其抗病毒免疫。不同鱼类I型干扰素在诱导表达特征 、抗病毒能力及受体利用等方面存在差异，但目前对于这些不同鱼类干扰素的表达调控机制及其在抗病毒免疫中的确切功能仍不清楚。我们前期通过大黄鱼基因组测序，发现了2种I型干扰素基因，其中1种为新的鱼类I型干扰素。它们在组织分布、诱导表达及启动子活性等方面存在明显不同。本项目拟在此基础上进一步研究该两种干扰素的抗病毒效应、对抗病毒基因的诱导、自诱导和相互诱导、及对转录因子IRF3和7的激活作用来明确它们的功能；通过启动子调控元件的删除突变、转录因子对其启动子活性的激活及EMSA等实验来阐明不同转录因子对该两种干扰素启动子的诱导激活作用；进而鉴定两种干扰素的受体及其所激活信号通路。研究结果将系统揭示两种大黄鱼I型干扰素在转录调控、功能及其信号通路等方面的异同，对于深入认识鱼类不同种I型干扰素的调控、功能及进化具有重要的意义。

Teleost fish possess multiple type I interferons (IFNs) to coordinate antiviral defenses. Previous studies have demonstrated that distinct type I IFNs of fish show significant differences in expression modulation, antiviral action and receptor usage among or within fish species. However, the regulation mechanisms of these distinct IFNs and their exact functions in antiviral immunity remain unclear in fish. We have found two type I IFN genes in large yellow croaker (Larimichthys crocea) from previous genome sequencing, one of which was a totally novel interferon gene in teleost fish. Furthermore, these two type I IFNs showed obvious differences in tissue distribution, expression modulation, and promoter constituent and activity. Based on these results, this project focuses on the antiviral properties, induction of antiviral genes, auto- or cross-induction of the two IFNs, and whether they could activate interferon regulation factor 3 and 7 (IRF3 and IRF7). We will also demonstrate the specific regulation of transcriptional factors (mainly IRF3 and IRF7) on two IFNs through promoter deletion mutation, promoter activity analysis controlled by various transcriptional factors and EMSA analyses. Finally, we will identify specific receptors and signal pathways for these two type I IFNs. These results may reveal the similarities and differences between two type I IFNs in mechanisms for transcriptional regulation, functions and signal pathways activated by them, which will be of important significance to further understand the regulation, function and evolution of distinct type I IFNs in bony fish.