Interferon (IFN)-stimulated genes (ISGs) exert multiple functions in immune system, and IFN-induced protein 35 (IFP35), which is a member of ISG, has been suggested to be involved in numerous cellular activities including the regulation of antiviral immunity in mammals. However, the role of IFP35 in fish innate immunity remains largely unknown. In the present study, we characterized the IFP35 gene in mandarin fish Siniperca chuatsi, which contains two conserved Nmi/IFP35 homology domains (NIDs) at C-terminus, but no leucine zipper motif, with its genomic DNA sequence consisting of eight exons and seven introns. High and constitutive mRNA level of IFP35 was observed in all examined tissues, with the highest level being observed in gills. Moreover, the IFP35 gene was significantly induced in vivo for 120 h following the infection of infectious spleen and kidney necrosis virus (ISKNV), and its mRNA and protein level was also significantly induced in vitro following the treatment of poly I:C, IFNh, IFNc, as well as IFN-γ. The subcellular localization results indicated that exogenous IFP35 protein was mainly located in cytoplasm, while endogenous IFP35 protein was transferred into, or aggregated around, the nucleus with the induction of poly I:C or IFNs. The dual luciferase activity analysis indicated that the IFP35 promoter was activated by type I and type II IFNs through ISRE site. It is considered that IFP35 in fish is involved in antiviral, as well as in IFN-induced innate immunity.

干扰素 (IFN) 刺激基因 (ISG) 在免疫系统中发挥多种功能，而作为 ISG 成员的 IFN 诱导蛋白 35 (IFP35) 被认为参与多种细胞活动，包括调节抗病毒免疫在哺乳动物中。然而，IFP35 在鱼类先天免疫中的作用仍然很大程度上未知。在本研究中，我们对鳜鱼Siniperca chuatsi 中的 IFP35 基因进行了表征，该基因在C 端包含两个保守的 Nmi/IFP35 同源结构域 (NID)，但没有亮氨酸拉链基序，其基因组 DNA 序列由 8 个外显子和 7 个外显子组成。内含子。在所有检查的组织中都观察到 IFP35 的高和组成型 mRNA 水平，在鳃中观察到最高水平。此外，IFP35 基因在体内被显着诱导感染性脾肾坏死病毒 (ISKNV) 120 h 后，在poly I:C、IFNh、IFNc 和 IFN-γ 处理后，其 mRNA 和蛋白水平在体外也显着诱导。亚细胞定位结果表明，外源性IFP35蛋白主要定位于细胞质，而内源性IFP35蛋白在poly I:C或IFNs的诱导下转移或聚集在细胞核周围。双荧光素酶活性分析表明 IFP35 启动子被 I 型和 II 型干扰素通过 ISRE 位点激活。认为鱼类中的 IFP35 参与抗病毒以及 IFN 诱导的先天免疫。