IRF-2调控鱼类干扰素基因及ISG基因的转录研究

Interferon regulatory factor (IRF) is an important transcription factor involved in transcription of type I IFN, IFN-stimulated genes (ISG) and other cytokine and chemokine genes by means of the binding to the characteristic elements within their promoters. There are many kinds of IRFs which have different functions in cells. Phylogenetic relationship analysis revealed that CiIRF2 acts as a repressor of ISG gene and belongs to the IRF1subfamily. Currently, little datum is available in fish function of IRF2. Our previous studies indicated that fish IRF2 down-regulated the transcription of IFN and ISG genes by playing an antagonistic role to IRF1. However, the process is not clearly. To further understand the function of fish IRF2, we plan to carry out the following studies. (1) To design promoter-mutants of ISG genes (including PKR, PKZ, ADAR1, IFN), for analyzing the transcriptional regulation mechanisms of IRF1 and IRF2. (2) Analysis of the relationship of IRF1 and IRF2 expression pattern, study the intrinsical inner link. (3) To study the competitive relation of IRF2 and IRF1 through binding the same promotor elements. (4) To explore the interaction of IRF2 with the positive regulator fact IRF1. This project will help us further understand the molecular mechanisms of interferon system genes transcription.

干扰素调节因子(IRF)是一种非常重要的转录调控因子，能够与启动子上的特异性元件结合，从而调节Ⅰ型干扰素基因、干扰素刺激基因(ISG)及其他细胞因子和趋化因子基因的转录。干扰素调节因子种类较多，功能各异。IRF-2属于IRF-1亚家族，是ISG转录的负调控因子。目前，对鱼类IRF2的功能研究还不多见，我们前期研究表明IRF2通过与IRF1的拮抗作用来下调鱼类ISG的转录水平，但其过程还不清楚。为进一步解析IRF2在其中的功能，拟开展如下工作：1、利用启动子突变研究IRF2和IRF1结合ISG (包括PKR、PKZ、ADAR1、IFN)启动子的顺式调控元件；2、分析IRF2与IRF1的表达特征，研究他们之间的内在联系；3、研究IRF2与IRF1竞争性结合ISG调控元件；4、探讨IRF2与IRF1等正调控因子之间的相互作用。该项工作的开展，有利于我们进一步了解鱼类干扰素系统基因转录的分子机制。

IRF-2属于IRF-1亚家族，是ISG转录的负调控因子。目前，对鱼类IRF2的功能研究还不多见，我们前期研究表明IRF2通过与IRF1的拮抗作用来下调鱼类ISG的转录水平，但其过程还不清楚。为进一步解析IRF2在其中的功能，我们开展了如下工作：1、凝胶阻滞实验发现草鱼IRF2可以与IFN以及PKR、PKZ的启动子有亲和性，双荧光素酶实验进一步证明草鱼IRF2可以显著抑制IFN及ISG基因的转录活性，而草鱼IRF1效果与之相反；2、共转染实验发现，草鱼IRF2与IRF1之间有明显的拮抗作用，草鱼IRF2可以抑制显著抑制IRF1对IFN和ISG基因的激活；3、进一步实验发现，草鱼IRF2还可以抑制IRF3或IRF7这两个IFN正调控因子对IFN的转录激活。