弓形虫真核表达质粒pcDNA3／GRA1的构建及序列测定

目的：构建弓形虫致密颗粒抗原-1(GRA1)真核表达质粒，为进一步开展DNA疫苗的保护性研究打下基础。方法：采用PCR扩增出编码GRAl目的基因，用EcoR Ⅰ／XhoⅠ分别对扩增产物和真核表达质粒pcDNA3进行双酶切，将GRA1定向克隆到pcDNA3 EcoRⅠ／XhoⅠ位点；对重组质粒进行PCR，双酶切初步鉴定后做序列测定。结果：特异扩增出预计的GRAl片段，大小为573bp；扩增产物双酶切后成功连接到pcDNA3中，经PCR，双酶切及序列测定结果表明重组质粒中含有GRA1读框。结论：成功构建弓形虫GRAl真核表达质粒。

Construction and sequencing of recombinant plasmid pcDNA3/GRA1 from Toxoplasma gondii]

OBJECTIVE: To construct a mammalian expression plasmid pcDNA3/GRA1 to express dense granules antigen-1 (GRA1) of Toxoplasma gondii, and to lay a foundation for further studying the protective immunity of pcDNA3/GRA1 as a DNA vaccine. METHODS: The GRA1 opening reading frame (ORF) was amplified with two specific primers. The ORF and plasmid pcDNA3 were digested with EcoR I and Xho I respectively and the ORF was ligated into the pcDNA3 at polylinker. The recombinant vector pcDNA3/GRA1 was characterized by PCR, restriction enzyme digestion, and sequencing analysis. RESULTS: The expected ORF, 573 bp long, was amplified by PCR, and inserted into plasmid pcDNA3. PCR, restriction enzyme digestion and sequencing analysis showed that pcDNA3/GRA1 contained GRA1 ORF with the right orientation. CONCLUSION: The mammalian expression vector pcDNA3/GRA1 is successfully constructed.