中文摘要：

ISG15由干扰素刺激基因15编码，是最早被发现的类泛素修饰分子．病毒感染以及干扰素刺激可以强烈诱导其表达．与泛素类似，ISG15可以共价连接到其他蛋白分子上进行修饰，但ISG15及其连接修饰的功能作用还有很多尚未知，最近的研究表明，ISG15及其修饰作用在先天免疫中起着重要的作用。将牛类ISG15基因克隆进入pET28a（＋）原核表达载体，并且表达了可溶的融合有Histag标签的bISG15融合蛋白．使用Ni-NTA葡聚糖进行纯化浓缩．纯化蛋白免疫Balb／c小鼠并获得抗血清．Western印迹实验显示，抗血清可以特异地识别在真核细胞中表达的bISG15．浓缩的bISG15以及制备的抗血清用于建立bISG15的体外修饰系统．实验证明，使用该系统bISG15可以连接到细胞蛋白上进行修饰。

英文摘要：

ISG15, the first ubiquitin-like molecule identified two decades ago, is encoded by interferon stimulated gene 15 （ISG 15）, where its robust expression can be induced by viral infections or interferon treatments. ISG 15 conjugate to other proteins as the ubiquitin and was found to be involved in innate immune response. However, the functions of ISG15 modification remained unclear. We cloned bovine ISG15（bisglS） into a prokaryotic expression vector pET28a（ ＋ ） with a His-tag to generate a soluble form of bISG15 fusion protein, and purified with Ni-NTA Sepharose chromatography. The purified protein was concentrated and used to immune Balb/c mice to raise the antiserum, which could specifically recognize bISG15 expressed in eukaryotic ceils by Western blot analysis. The concentrated bISG15 protein and its antiserum were then used to establish an in vitro bISG15 modification system. Our studies have demonstrated that cellular proteins could be conjugated to bISG15 with this system.