畜牧兽医学报 ›› 2010, Vol. 41 ›› Issue (9): 1166-1171.doi:

• 预防兽医 • 上一篇    下一篇

牛气管抗菌肽的原核表达、体外抗菌活性及其组织分布分析

高小艳1,2,王长法1*,刘顺德2,李秋玲1,杨宏军1,杨少华1,仲跻峰1,何洪彬1*   

  1. 1.山东省农业科学院奶牛研究中心,济南250100;2.宁夏大学农学院动物科学系动物遗传育种与繁殖实验室,银川750021
  • 收稿日期:1900-01-01 修回日期:1900-01-01 出版日期:2010-09-20 发布日期:2010-09-20
  • 通讯作者: 王长法;何洪彬

Cloning, Expression of Bovine Tracheal Defensin in E.coli and Its Antibacterial Activity and Tissue Distribution

GAO Xiao-yan1,2,WANG Chang-fa1*, LIU Shun-de2, LI Qiu-ling1, YANG Hong-jun1,YANG Shao-hua1,ZHONG Ji-feng1, HE Hong-bin1*

  

  1. 1. Cow Research Center, Agricultural Science Academy of Shandong Province, Jinan 250100, China;2. College of Animal Science,Ningxia University,Yinchuan 750021, China
  • Received:1900-01-01 Revised:1900-01-01 Online:2010-09-20 Published:2010-09-20

摘要: 本文旨在对牛气管抗菌肽(tracheal antimicrobial peptide,TAP)基因进行原核表达,以及研究重组蛋白的抗菌活性,并分析TAP在各组织的表达分布情况,为开展转TAP基因抗乳腺炎奶牛研究提供技术资料。作者采用RT-PCR从荷斯坦奶牛气管扩增TAP基因,分析其序列后根据大肠杆菌表达系统对密码子的偏好性,人工合成牛TAP基因,构建pET32a(+)-TAP重组质粒;然后转化大肠杆菌BL21,IPTG诱导表达并纯化。对表达蛋白进行SDSPAGE、Western Blot鉴定;在线软件分析目的蛋白表达量。采用滤纸片法测定重组牛TAP的体外抗菌活性,并用RT-PCR法分析牛各组织中TAP表达情况。测序结果表明,扩增到114 bp目的基因片段,可编码含38个氨基酸残基的成熟蛋白。SDSPAGE分析表达的融合蛋白相对分子质量为24 ku,重组蛋白以可溶性方式存在,表达量占菌体总蛋白的52.1%。Western Blot检测只出现单一条带。抗菌效价分析表明0.115 μg·μL-1重组蛋白对牛源金黄色葡萄球菌有一定的抗菌活性。TAP基因在奶牛咽喉、肺、气管、小肠、肝、心脏及口腔黏膜中均有表达,在鼻黏膜和舌黏膜中微量表达,在皮肤中几乎不表达。作者成功表达了牛TAP基因,重组牛TAP蛋白在大肠杆菌中实现高效表达,并具有一定的抗奶牛乳腺炎致病菌的活性,为未来培育抗乳腺炎转基因奶牛及相关基因工程产品的开发奠定了基础。

Abstract: The study was conducted to clone bovine tracheal antimicrobial peptide gene (TAP) from bovine tracheas, and recombinant bovine TAP protein was expressed in E. coli. Its antimicrobial activity were determined. In addition, the tissue distribution of the TAP gene in bovine was investigated. The mRNA of bovine TAP was cloned from tracheas of Holstein cow by RT-PCR. Based on the analysis of the sequence of bTAP and the codon preference in E.coli expression system, the bovine TAP gene was synthesized and inserted into vector pET32a(+) to construct plasmid pET32a(+)-TAP. The plasmid was expressed in E. coli BL21(DE3) cell by induction of IPTG. The recombinant fusion protein was purified, and determined by SDS-PAGE and Western Blot. Antimicrobial activity of the recombinant fusion protein were measured by filter paper method. Tissues distribution of the TAP gene has been demonstrated in bovine by RT-PCR. The full length cDNA of bovine TAP was consisted of 114 bp, encoding 38 amino acid residues. Western Blot results showed that the recombinant proteins were expressed in E. coli with molecular weight of 24 kD, exists in soluble form and accounted for 52.1% of the whole bactera proteins. A single band appeared in Western Blot detection. The content of 0.115 μg·μL-1 of the purified TAP protein had antibacterial activity against bovine Sta.Aureus in vitro. Bovine TAP mRNA was widely expressed in the tissues of bovine, such as throat, lungs, trachea, small intestine, liver, heart, oral mucosa, and it was micro-expressed in the nasal mucosa, lingual mucosa and almost not expressed in the skin. The results showed that bovine TAP protein was highly expressed in E. coli, and can be used for transgenic dairy cow which anti-mastitis and developing the product of genetic engineering in future.