Zhang Bao-cun, Zhang Jian, Xiao Zhi-zhong, Sun Li
Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; Graduate University of the Chinese Academy of Sciences, Beijing 100049, China.
Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China.
Dev Comp Immunol. 2014 Jul;45(1):35-42. doi: 10.1016/j.dci.2014.02.001. Epub 2014 Feb 10.
Viperin in mammals is known to be an antiviral protein that inhibits the replication of diverse DNA and RNA viruses. In teleost, viperin homologues have been identified in a large number of species and, in some cases, are stimulated in transcription by viruses. However, the biological significance of fish viperin protein in antiviral immunity has not been investigated. In this study, we identified a viperin homologue from rock bream (Oplegnathus fasciatus) (named OfVip) and examined its expression pattern, subcellular localization, and immune effect. We found that OfVip expression occurred in eight tissues, and experimental challenge of rock bream with the viral fish pathogen megalocytivirus upregulated OfVip expression in kidney, liver, and spleen. OfVip was localized in the endoplasmic reticulum under normal physiological conditions, and viral infection induced subcellular redistribution of OfVip. Transient transfection of cultured fish cells with an OfVip-expressing plasmid caused enhanced cellular resistance against megalocytivirus challenge. Consistently, in vivo study showed that rock bream overexpressing OfVip exhibited significantly reduced viral loads in tissues following experimental infection with megalocytivirus. Furthermore, OfVip upregulated the expression of a wide range of immune genes, including those that are known to participate in antiviral immunity. Taken together, these results indicate for the first time that a teleost viperin is a virus-responsive protein that is modulated in subcellular localization by viral infection, and that viperin regulates the immune reactions of the host fish in a manner that augments resistance against viral infection.
在哺乳动物中，蝰蛇毒蛋白是一种抗病毒蛋白，可抑制多种DNA和RNA病毒的复制。在硬骨鱼中，已在大量物种中鉴定出蝰蛇毒蛋白同源物，在某些情况下，它们会受到病毒的转录刺激。然而，鱼类蝰蛇毒蛋白在抗病毒免疫中的生物学意义尚未得到研究。在本研究中，我们从条石鲷（Oplegnathus fasciatus）中鉴定出一种蝰蛇毒蛋白同源物（命名为OfVip），并检测了其表达模式、亚细胞定位和免疫效应。我们发现OfVip在八个组织中表达，用病毒性鱼类病原体巨细胞病毒对条石鲷进行实验性攻击后，肾脏、肝脏和脾脏中的OfVip表达上调。在正常生理条件下，OfVip定位于内质网，病毒感染诱导OfVip的亚细胞重新分布。用表达OfVip的质粒瞬时转染培养的鱼类细胞，可增强细胞对巨细胞病毒攻击的抗性。同样，体内研究表明，过表达OfVip的条石鲷在感染巨细胞病毒后，组织中的病毒载量显著降低。此外，OfVip上调了多种免疫基因的表达，包括那些已知参与抗病毒免疫的基因。综上所述，这些结果首次表明，硬骨鱼蝰蛇毒蛋白是一种病毒反应蛋白，其亚细胞定位受病毒感染调节，并且蝰蛇毒蛋白以增强宿主鱼类对病毒感染抗性的方式调节宿主的免疫反应。
