Characterization And Role Of IRF9 In Immune Signal Pathways In Miichthys Miiuy

Interferon regulatory factors are a very important member in many kinds of transcription factors.The earliest function was discovered that it could regulate the expression of interferon.All interferon regulatory factor family members can regulate interferon and interferon related genes.In addition,it plays an essential role in immune response,antiviral,cell growth regulation and apoptosis.So far,a large number of family members of interferon regulatory factors have been studied in mammals,but it is relatively rare in lower vertebrates.In this paper,the IRF9 gene of miiuy croaker was identified,and the molecular characteristics and evolution characteristics were analyzed.In addition,the regulation function of IRF9 gene is also studied.The main conclusions are as follows:(1)The full-length sequence of the IRF9 gene from miiuy croaker is obtained from the genome.The length of its ORF region is 1305 bp,encoding 434 amino acids.The comparative analysis of the miiuy croaker IRF9 gene structure and the IRF9 gene structure of other species found that IRF9 gene of miiuy croaker was consistent with the IRF9 of other lower vertebrates,and they had similar structures and a very conservative domain.(2)In fish,the IRF9 gene of miiuy croaker has very conservative synteny,and its upstream and downstream genes are rnf31 and emc9 respectively.In amphibian and mammal comparative analysis,IRF9 gene has also very conservative synteny,and its upstream and downstream genes are rnf31 and rec8 respectively.(3)The IRF9 gene belongs to the IRF4 subfamily,and the IRF4 subfamily genes include IRF4,IRF8,IRF9 and IRF10 genes.According to the results of phylogenetic tree analysis of IRF4 subfamily,IRF4 is an independent branch,but it has relatively strong homology with IRF10.In addition,all quadruped IRF9 genes were clustered together,and all fish IRF9 genes were clustered on one branch.In the course of evolution,IRF9 gene has been found and studied in other vertebrates except birds.(4)The results of real-time fluorescence quantitative analysis showed that IRF9 can be widely expressed in many tissues.In normal tissue,infected tissues and macrophages,IRF9 gene was expressed and the expression of IRF9 in liver,kidney and macrophage was increased after the stimulation of poly(I:C).(5)Immunofluorescence result analysis revealed that IRF9 gene was mainly distributed in the cytoplasm of Hela cells.(6)The double luciferase reporter gene assay showed that IRF9 can induce the expression of IFN? and IFN ? reporter genes.(7)The IRF9 gene can inhibit TRIF mediated NF-?B signaling pathway,and IRF9-shRNA can alleviate this inhibition by knocking down the expression of IRF9 gene.In addition,we found that the domain of inhibition was mainly the DBD domain of IRF9 gene.