小鼠CXCR4基因慢病毒载体构建与真核表达

本研究旨在克隆小鼠CXC型趋化因子受体4（CXCR4）基因，构建携带增强型绿色荧光蛋白（EGFP）的CXCR4重组慢病毒载体并在真核细胞中表达。采用逆转录-聚合酶链式反应（RT-PCR）以C57BL／6小鼠骨髓细胞为模板克隆全长型CXCR4基因，连接至克隆载体pCR-Blunt，经限制性内切酶酶切后亚克隆至慢病毒转移载体，构建携带EGFP及CXCR4双顺反子结构的自身失活型重组慢病毒表达质粒；同时构建LV-IRES-EGFP作为对照质粒；通过脂质体转染法与包装质粒及包膜蛋白质粒共转染包装细胞293FT，超速离心浓缩病毒颗粒后转染293FT细胞，采用荧光显微镜和流式细胞术（FCM）检测EGFP的表达，Western blot鉴定CXCR4蛋白表达。结果表明，成功克隆小鼠CXCR4基因，构建重组慢病毒转移质粒LV-IRES-EGFP-CXCR4及对照质粒LV-IRES-EGFP，三质粒系统共转染293FT细胞后获得病毒滴度可达到10^8TU／ml。以重组慢病毒颗粒感染293Fr细胞后第3天，在荧光显微镜下观察到较强绿色荧光表达，FCM检测显示感染效率可达95％，FCM及Western blot结果显示感染后293Fr细胞表达CXCR4蛋白。结论：成功构建自身失活型慢病毒载体LV-IRES-EGFP-CXCR4，并在真核细胞中获得表达。

Construction of Lentiviral Vector for Mouse CXC Chemokine Receptor 4 Gene and Its Expression in Eukaryotic Cells

This study was aimed to clone the gene coding mouse CXC chemokine receptor 4 （ CXCR4）, to construct the recombinant lentiviral vector carrying enhanced green fluorescence protein （EGFP） and to explore its expression in eukaryotic cells （293FT cells）. The full length CXCR4 gene was cloned by RT-PCR using bone marrow cells from C57BL/6 mouse as template and inserted into PCR-Blunt vector. CXCR4 fragment was generated by digestion with restriction endonuclease and subcloned into a lentiviral vector to generate recombinant lentiviral vector LV-IRES-EGFP- CXCR4, which was co-transfected into 293PT cells together with envelope plasmid and packaging plasmid by lipofectamine 2000. Viruses were gathered and concentrated using ultracentrifuge, and then transfected into 293Fr cells. Expression of EGFP was detected by fluorescent microscopy and flow cytometry （FCM）. And the exprossion of CXCR4 protein was detected by Western blot. The results demonstrated that mouse CXCR4 gene was cloned and the lentivirai vector was successfully constructed. The lentiviral particles were correctly packaged, and the virus titers were above 108 TU/ml in the supernatant after concentration. Expression of EGFP was detected by fluorescent microscopy in the transfected 293FT cells, and the transfection efficacy 〉 95% was determined by FCM. Expression of CXCR4 protein detected by FCM and Western blot was significantly higher than that in control group. It is concluded that the CXCR4 gene along with the gene coding EGFP is successfully inserted into a lentiviral vector to construct a recombinant lentivirai vector, which can be expressed in eukaryotic cells.