目的在能够转化小鼠沙眼衣原体的穿梭质粒pGFP::CM中加入新的开放读码框,为研究衣原体单个蛋白功能奠定基础。方法用聚合酶链反应(PCR)扩增质粒pGFP::CM和新的开放读码框(包括质粒蛋白pgp4的启动子、红色荧光蛋白mCherry基因和沙眼衣原体CT579的转录终止序列),将连接产物转化至大肠埃希菌感受态Stellar中,提取质粒进行PCR、酶切和测序鉴定。将重组质粒利用氯化钙法转化至无质粒的CMUT3中,荧光显微镜下观察并挑选带有荧光的转化衣原体包涵体,经过氨苄西林筛选和噬菌斑纯化后,采用间接免疫荧光染色法检测转化株CMUT3-pGFP·mCherry-CM中pgp3和glgA蛋白的表达。结果经PCR、酶切和测序鉴定后得到正确序列的重组质粒,转化CMUT3后可见含有绿色和红色荧光的衣原体包涵体。氨苄西林筛选和噬菌斑实验纯化后得到新的转化株CMUT3-pGFP-mCherry-CM。免疫荧光证实pgp3和glgA蛋白在衣原体CMUT3-pGFP-mCherry-CM和CMUT3-pGFP::CM中表达相似。结论在质粒pGFP::CM中成功加入开放读码框,转化衣原体后能够表达外源性基因,使衣原体转化技术能够用于衣原体蛋白质功能研究,为临床沙眼衣原体感染的防治提供新的线索。
Objective To add an open reading frame in the shuttle vector of pGFP :: CM for transfection of exogenous genes into Chlamydia muridarum. Methods The sequence of plasmid pGFP :: CM and new open reading frame (including promoter of pgp4, mCherry gene of red fluorescence protein and transcription termination sequence of Chlamydia trachomatis CT579 ) were amplified by polymerase chain reaction (PCR) , and the products were transfected into Stellar competent cells. The recombinant plasmids were identified by PCR, enzyme digestion and sequencing. Then the recombinant plasmid was transfected into plasmid-free strain CMUT3, and the GFP- and mCherry-positive inclusions were observed under the fluorescence microscope. After the ampicillin selection and plaque purification, the purified CMUT3-pGFP- mCherry-CM was identified by indirect immunofluorecesent stain using anti-pgp3 and anti-glgA antibodies. Results The correct recombinant plasmid after sequencing identification, enzyme digestion and PCR amplification was successfully transfected into CMUT3, and the GFP- and mCherry-positive inclusions were observed. The transfected strain CMUT3-pGFP-mCherry-CM was purified after ampicillin selection and plaque purification. The expression of pgp3 and glgA protein in CMUT3-pGFP-mCherry-CM was similar to that in CMUT3-pGFP :: CM. Conclusion An open reading frame is successfully added in the plasmid pGFP :: CM, and the new plasmid can be transfected into CMUT3 and express exogenous protein, which can be used for further study on the function of single chlamydial protein.