Lin Jing-Yun, Hu Guo-Bin, Liu Da-Hai, Li Song, Liu Qiu-Ming, Zhang Shi-Cui
College of Marine Life Sciences, Ocean University of China, Qingdao 266003, China.
College of Marine Life Sciences, Ocean University of China, Qingdao 266003, China; Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao 266003, China.
Fish Shellfish Immunol. 2015 Aug;45(2):895-900. doi: 10.1016/j.fsi.2015.05.050. Epub 2015 Jun 18.
The interferon stimulated gene 15 (ISG15) is strongly induced in many cell types by double-stranded RNA (polyinosinic: polycytidylic acid, poly I:C) and viral infection. In this study, we described the nucleotide, mRNA tissue distribution and regulation of an ISG15 gene from turbot, Scophthalmus maximus (SmISG15). SmISG15 gene is 862 bp in length, composed of two exons and one intron, and encodes 158 amino acids. The deduced protein exhibits the highest homology (44.7-71.2% identity) with ISG15s from other fishes and possesses two conserved tandem ubiquitin-like (UBL) domains and a C-terminal RLRGG conjugating motif known to be important for the functions of ISG15s in vertebrates. Phylogenetic analysis grouped SmISG15 into fish ISG15. SmISG15 mRNA was constitutively expressed in all tissues examined, with higher levels observed in immune organs. Gene expression analysis was performed for SmISG15 in the spleen, head kidney, gills and muscle of turbots challenged with poly I:C or turbot reddish body iridovirus (TRBIV) over a 7-day time course. The result showed that SmISG15 was upregulated by both stimuli in all four tissues, with induction by poly I:C apparently stronger and initiated more quickly. A two-wave induced expression of SmISG15 was seen in the spleen, head kidney and gills, suggesting an induction of SmISG15 either by IFN-dependent or -independent pathway. These results provide insights into the roles of fish ISG15 in antiviral immunity.
干扰素刺激基因15（ISG15）在许多细胞类型中被双链RNA（聚肌苷酸：聚胞苷酸，聚I:C）和病毒感染强烈诱导。在本研究中，我们描述了大菱鲆（Scophthalmus maximus）ISG15基因（SmISG15）的核苷酸序列、mRNA组织分布及其调控。SmISG15基因长度为862 bp，由两个外显子和一个内含子组成，编码158个氨基酸。推导的蛋白质与其他鱼类的ISG15具有最高的同源性（同一性为44.7 - 71.2%），并拥有两个保守的串联泛素样（UBL）结构域和一个C末端RLRGG缀合基序，已知该基序对脊椎动物中ISG15的功能很重要。系统发育分析将SmISG15归入鱼类ISG15。SmISG15 mRNA在所有检测的组织中组成性表达，在免疫器官中表达水平更高。在7天的时间进程中，对用聚I:C或大菱鲆红体虹彩病毒（TRBIV）攻击的大菱鲆的脾脏、头肾、鳃和肌肉中的SmISG15进行了基因表达分析。结果表明，在所有四个组织中，两种刺激均使SmISG15上调，聚I:C的诱导作用明显更强且启动更快。在脾脏、头肾和鳃中观察到SmISG15的两波诱导表达，表明SmISG15可能通过IFN依赖性或非依赖性途径被诱导。这些结果为鱼类ISG15在抗病毒免疫中的作用提供了见解。
