鸡IL-2受体α亚基成熟蛋白基因的克隆及其胞外段的原核表达

Cloning of gene encoding the mature protein of chicken IL-2 receptor α chain and prokaryotic expression of the extracellular domain fragment

以鸡脾淋巴细胞总RNA为模板，采用RT—PCR方法克隆了鸡白细胞介素-2受体α亚基（ChIL-2Rα）编码区基因。将ChIL-2Rα胞外段基因克隆到pET-32a（＋）中，获得重组质粒pET32a—exChIL-2Rα，转化宿主菌E．coli Rosseta^TM（DE3）后，经IPTG诱导表达的融合蛋白大小约为34ku。序列分析发现，鸡IL-2Rα编码区基因与GenBank上已登录序列的核苷酸同源性为99．2％，氨基酸同源性为99．5％。ChIL-2Rα与其他哺乳动物IL-2Rα在核苷酸和氨基酸水平上的同源性分别为29．6％～54．5％和18．8％～28．0％。表明，禽类IL-2Rα与哺乳类的差异较大。

The gene encoding mature protein of chicken interleukin-2 receptor alpha chain（ChIL-2Rα） was cloned from the total RNA of chicken spleen lymphocyte by RT-PCR. The cDNA sequence encoding ChIL-2Rα extracellular domain （exChIL-2Rα） was amplified and subcloned into the expression vector pET32α（＋） to construct recombinant plasmid pET32a-exChIL-2Rα. The pET32a-exChIL-2Rα was expressed in Escherichia coli RossetaTM （DE3） induced with IPTG,and the expressed protein was 34 ku in size. In results of the sequence analysis,the identity of ChIL-2Rα with that in GenBank was 99.2% at nucleotide level and 99.5% at amino acid level. ChIL-2Rα had the low identities with those of other mammalian,ranging from 29.6% to 54.5% at nucleotide level and from 18.8% to 28.0% at amino acid level. The results demonstrated that ChIL-2Rα of chicken was significantly different from that of mammalian.