结核分枝杆菌抗原蛋白ESAT—6基因重组穿梭质粒的构建与鉴定

目的：构建分泌性表达结核分枝杆菌抗原蛋白ESAT－6的重组卡介苗，方法：分别以卡介苗（BCG）和结核分枝杆菌H37Rv株基因组DNA为模板。通过PCR扩增得到的117bp的BCGα抗原（α－Ag)信号肽序列和285bp的结核杆菌esat-6基因序列，将esat-6基因与大肠杆菌－卡介苗穿梭质粒载体pMV261重组，得到重组质粒pME,再将BCGα－Ag信号肽序列克隆至pME中，得到重组质粒pSME。结果：质粒pSME用双酶切和PCR扩增鉴定证实，克隆基因α-Ag信号肽序列和esat-6正确插入载体pMV261，结论：重组质粒pSME可望在BCG中分泌性表达结核分枝杆菌的免疫保护性抗原蛋白ESAT－6，该质粒的构建成功为改造卡介苗，发展新型结核病疫苗奠定了基础。

Construction and identification of recombinant shuttle-plasmid with ESAT-6 from Mycobacterium tuberculosis]

OBJECTIVE: To construct a recombinant BCG secretively expressing ESAT-6 of Mycobacterium tuberculosis. METHODS: alpha-antigen(alpha-Ag) signal sequence and esat-6 gene were amplified from the genome of Bacille Calmette-Guerin (BCG) and Mycobacterium tuberculosis by PCR respectively. esat-6 gene was cloned in E. coli-BCG shuttle-plasmid pMV261 to get pME. Then a new recombinant plasmid pSME was constructed by inserting BCG alpha-Ag signal sequence into pME. RESULTS: The cloned genes alpha-Ag signal sequence and esat-6 were correctly inserted into the vector pMV261, which was confirmed by restriction endonuclease digestion and PCR amplification of pSME. CONCLUSION: pSME was expected to secretively express ESAT-6 of Mycobacterium tuberculosis in BCG. This study provides the possibility of further researches on the development of new anti-tuberculosis vaccine.