Molecular cloning and functional characterization of interferon regulatory factor 7 of the barbel chub, Squaliobarbus curriculus.
Molecular cloning and functional characterization of interferon regulatory factor 7 of the barbel chub, Squaliobarbus curriculus.
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DOI：
10.1016/j.fsi.2017.08.024
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发表时间：
2017-10
影响因子：
4.7
通讯作者：
Xin Zhao;Ronghua Wang;Yaoguo Li;T. Xiao
中科院分区：
文献类型：
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作者：
Xin Zhao;Ronghua Wang;Yaoguo Li;T. Xiao
干扰素调节因子7（interferon regulatory factor 7，IRF 7）是I型干扰素依赖性免疫反应的重要调节因子，在机体抗病毒免疫中起重要作用。为了研究赤眼鳟IRF 7（ScIRF 7）的抗病毒功能，克隆了赤眼鳟ScIRF 7的cDNA序列，并对其进行了结构分析。ScIRF 7的cDNA全长为1870 bp，由41 bp的5′-UTR、560 bp的3′-UTR和1269 bp的开放阅读框（ORF）组成。该基因编码423个氨基酸，分子量为49.426 KDa，理论等电点为5.71。ScIRF 7蛋白具有IRF家族的典型结构域，包括一个保守的N端DBD结合结构域、一个C端IRF结合结构域和一个富含丝氨酸的结构域。在DBD中，发现四个色氨酸位点在所有物种中高度保守，而在哺乳动物的另一个保守的色氨酸位点，相应的氨基酸是鱼类的甲硫氨酸。ScIRF 7在脾脏中的表达量最高，在肝脏中的表达量最低。IFN-β在鳃中的表达量最高，在肝脏中的表达量最低。感染GCRV后，ScIRF 7在脾脏和鳃中的表达水平变化总体上呈现先上调后下调的趋势，其中感染后24 h外周血淋巴细胞中ScIRF 7的表达水平最高。在pEGFP-ScIRF 7过表达细胞中，ScIRF 7的mRNA表达先上调后下调，IFN-β的表达在感染后12 h较对照组显著上调（P<0. 05），且显著高于pEGFP-N1过表达细胞。结果表明ScIRF 7可能在黄颡鱼抗GCRV的免疫应答中起关键作用，并可能在草鱼肾细胞中起作用。
The interferon regulatory factor 7 (IRF7) is a critical regulator of type-I interferon-dependent immune reaction that defense against virus. To investigate the antiviral function ofIRF7of barbel chubSqualiobarbus curriculus(ScIRF7), the cDNA ofScIRF7was cloned and characterized. The full length cDNA ofScIRF7was 1870 bp, consisted of 41 bp 5′-UTR, 560 bp 3′-UTR and a 1269 bp open reading frame (ORF). The ORF encoded 423 amino acids with a molecular weight of 49.426 KDa and a theoretical isoelectric point of 5.71. The putativeScIRF7protein possesses typical domains ofIRFfamily including a conserved N-terminal DBD-binding domain (DBD), a C-terminal IRF association domain and a serine-rich domain. In the DBD, four tryptophans were found to be highly conserved among all species, whilst in another conserved tryptophan site of mammals, the corresponding amino acids were methionine for fishes. The expression level ofScIRF7was highest in the spleen and lowest in the liver. The expression level ofIFN-βwas highest in the gill and lowest in the liver. After GCRV infection, expression levels changes ofScIRF7showed an overall tendency of firstly up-regulation and then down-regulation in the spleen and the gill; and expression levels ofScIRF7in peripheral blood lymphocyte at 24 h post-infection was highest among all time points. In pEGFP-ScIRF7 overexpressing cells, the mRNA level ofScIRF7was firstly up-regulation and then down-regulation; and the expression ofIFN-βwas significantly up-regulated at 12 h post-infection than that of control group (P< 0.05), which was significantly higher than those in pEGFP-N1 overexpressing cells. The results indicated thatScIRF7may play a key role in immune responses of barbel chubSqualiobarbus curriculusagainst GCRV and may also functions in theCtenopharyngodon idelluskidney cells.