Recently, new progress has been made in regulation of vertebrate IFN response by the Research Group of Fish Developmental Genetics and Cell Engineering of Institute of Hydrobiology, Chinese Academy of Sciences (IHB) led by Prof. GUI Jianfang. 

IFN response was the first line for host against viral infection in vertebrate. In mammals, interferon regulatory factor 3 (IRF3) is the main regulator for initiation of IFN response. The present study found that fish IRF3, similar to mammalian orthologs, could induce the expression of IFN and ISGs, which indicates that regulation of IFN response by IRF3 is an ancient trait in vertebrate. However, fish IRF3 could be induced by IFN, but mammalian IRF3 not, which is further verified by promoter analysis of vertebrate IRF3 genes revealed the presence of typical ISRE in fish and amphibians only. Furthermore, fish IFN could induce the phosphorylation and cytoplamic-to-nuclear translocation of IRF3, which in turn initiate the transcription of IFN. In view of the activation of mammalian IRF3 only in viral-infected cells, IHB researchers inferred that regulation of IFN response by IRF3 is rough in fish and amphibians, but accurate and mature in mammals. 

This work was supported by grants from the 973 National Basic Research Program of China. The research was fulfilled by IHB Ph.D student Sun Fan et al. under the supervision of Profs. GUI Jianfang and ZHANG Yibing. The related article was published online in Journal of Immunology on November 17, 2010 (http://www.jimmunol.org/content/early/2010/11/17/jimmunol.1002401).