尼罗罗非鱼γ-干扰素基因的克隆、结构分析及组织表达

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

  • 摘要: 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cDNA,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 IFN γ)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IFN γ晶体结构最相似。qPCR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 IFN γ在脾脏、肾和鳃中的表达均显著上调(P < 0.05)。On IFN γ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 IFN γ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。

     

    Abstract: 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.

     

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