PCR介导嗜肺军团菌疫苗候选基因lvgA和Hsp60的融合及其在大肠杆菌中表达的初步研究  

Legionella pneumophila lvgA and Hsp60 gene splicing and the fusion gene expression in E. coli

作　　者：刘明杰[1] 陈建平[1] 王涛[1] 廖涛[2] 陈宪[1] 芦殿香 田玉[1] 

机构地区：[1]四川大学华西医学中心基础医学与法医学院寄生虫学教研室,四川成都610041 [2]川北医学院附属医院检验科,四川泸州637000 [3]四川大学生物材料工程研究中心,四川成都610064

出　　处：《南方医科大学学报》2006年第7期904-909,共6页Journal of Southern Medical University

基　　金：国家自然科学基金(30300302)~~

摘　　要：目的采用PCR法进行嗜肺军团菌lvgA和Hsp60二基因的拼接融合,克隆并检测该融合基因在原核系统中表达情况,为进一步研究其免疫性能作必要的准备。方法采用重组聚合酶链反应,设计引物首先分别从嗜肺军团菌基因组DNA中扩得待融合端互补的军团菌毒力基因(lvgA)和热休克蛋白60基因(Hsp60),经琼脂糖电泳纯化回收,再以适量lvgA和Hsp60为模板变性、退火、重叠延伸,实现二基因的PCR水平融合,随后采用外引物进行新一轮扩增,扩得足量lvgA/Hsp60融合基因的PCR产物,继而将其定向克隆至原核表达载体pGEX-4T-1,构建原核表达重组质粒,转化宿主菌BL21,经PCR、酶切及测序鉴定后,IPTG诱导表达,产物进行SDS-PAGE电泳、免疫印迹分析等鉴定。结果扩增出了约2292bp的lvgA/Hsp60融合基因,构建了原核表达重组质粒pGlvgA/Hsp60,并检测到Mr约117000的GST-lvgA-Hsp60融合蛋白表达条带。结论采用PCR法实现了嗜肺军团菌lvgA和Hsp60二基因的融合,构建了其原核表达重组质粒,并使该融合蛋白在原核系统中得到了有效的表达,为进一步研究该融合基因的免疫学特性奠定了基础.Objective To fuse Legionella virulence gene （lvgA） with heat shock protein 60 gene （Hsp60） by PCR and detect the fusion gene expression in E.coli. Methods The fragments oflvgA and Hsp60 genes having matching sequences at their ends to be fused were amplified from the genomic DNA of Legionella pneurnophila by PCR, and the PCR products were mixed, denatured, rearmealed, so that the strands with matching sequences at their 3＇ ends overlapped to serve as primers for each other. Extension of this overlap by DNA polymerase produced recombinant products. After amplification with outer primers, sufficient product of the fusion gene was harvested, which was inserted into the prokaryotic expression vector pGEX-4T-1 to construct the prokaryotic expression recombinant plasmid. After identification with restrictionenzyme analysis, polymerase chain reaction and nucleotide sequence analysis, the E.coli BL21 containing the recombinant plasmid pGlvgA/Hsp60 was induced with IPTG and the expression of lvgA/Hsp60 was detected by SDS-PAGE and Western blot analysis. Results The lvgA/ltsp60 fusion gene of 2 292 bp was amplified and the recombinant plasmid pGlvgA/Hsp60 was constructed successfully. A 117-kD GST-lvgA-Hsp60 fusion protein was detected in the E.coli containing the recombinant plasmid. Conclusion The recombinant plasmid for Legionella pneurnophila lvgA/Hsp60 fusion gene is constructed successfully and this fusion protein can be expressed in prokaryotic cells efficiently, which make possible the immunological characterization of this fusion gene.

关 键 词：嗜肺军团菌 lvgA基因 Hsp60基因 重组聚合酶链反应 基因表达 

分 类 号：R378[医药卫生—病原生物学]