尼罗罗非鱼γ-干扰素基因的克隆、结构分析及组织表达

γ-干扰素(interferon,IFN)是调控天然免疫与细胞免疫的一种重要细胞因子,在抵抗病毒入侵和细菌感染中发挥重要作用。该研究从尼罗罗非鱼(Oreochromis niloticus)脾脏组织中扩增到γ-干扰素基因的c DNA,大小为621 bp,编码206个氨基酸。生物信息学分析表明,尼罗罗非鱼γ-干扰素分子(On IFNγ)具有信号肽、IFN特征序列及核定位信号。预测的三级结构与人类IFNγ晶体结构最相似。q PCR检测显示,IFNγ在正常鱼体内的脾脏中表达量最高,其次是肠、鳃和肾脏。感染无乳链球菌(Streptococcus agalactiae)后,On IFNγ在脾脏、肾和鳃中的表达均显著上调(P0.05)。On IFNγ在相关免疫器官中的高表达、受感染后的表达上调,说明其在罗非鱼免疫防御中可能具有重要作用。该研究为进一步开展On IFNγ基因的功能研究、探讨其在抗病转基因及抗病选育中的开发应用奠定了基础。

Cloning,structure analysis and expression of interferon gamma (IFN-γ) gene in Oreochromis niloticus

Interferon-γ is a cytokine crucial for the regulation of both natural and cellular immunity,playing an important role in defending against virus invasion and bacterial infection.In this study,the cDNA of interferon-γ genes was amplified from the spleen tissues of Nile tilapia;this cDNA had an open reading frame of 621 bp,encodeing 206 amino acids.Bioinformatics analysis shows that the interferon-γ molecule of Nile tilapia contains one signal peptide and one nuclear localization signal.Its tertiary structure was similar with the crystal structure of human interferon-γ.Real-time fluorescent quantitative polymerase chain reaction(PCR)shows that the expression level of interferon-γ gene was the highest in the spleen of normal Nile tilapia,followed by the intestines,gills and kidneys(P<0.05).Both the high expression of interferon-γ in immune-associated tissues and its upregulated expression after GBS infection reveal the significant role of interferon-γ in the immune defense of Nile tilapia.This study lays foundation for further research on the function of interferon-γ gene in Nile tilapia as well as its development and application in transgenesis and selective breeding for disease resistance.