人胶质细胞源性神经营养因子和血管内皮生长因子165双基因真核表达载体的构建与鉴定

背景：人胶质细胞源性神经营养因子（glialcell line-derived neurotrophic factor,GDNF）和血管内皮生长因子165（vascular endothelial growth factor 165,VEGF165）在细胞分化过程中有重要作用。目的：构建双基因共表达载体pIRES2-GDNF-VEGF165并对其进行鉴定。方法：采用PCR法从人外周血单个核细胞的基因组DNA中获取人胶质细胞源性神经营养因子基因,然后将人胶质细胞源性神经营养因子的cDNA片段插入到pIRES2-EGFP多克隆位点构建成为pIRES2-GDNF-EGFP。人血管内皮生长因子165 cDNA片段是通过双PCR的方法从pIRES2-VEGF165-EGFP质粒中获取,接着将血管内皮生长因子165 cDNA片段以替换EGFP的方式插入pIRES2-BDNF-EGFP中,最后构建成为含有内部核糖体进入位点（IRES）的pIRES2-GDNF-VEGF165双基因共表达载体。通过双酶切和DNA测序方法对其鉴定,将重组的双基因共表达载体感染HEK293细胞,利用RT-PCR与Western-blot方法检测双基因的表达。结果与结论：DNA测序显示,提取的人胶质细胞源性神经营养因子和血管内皮生长因子165均与基因库报道序列一致,相对分子质量分别为636 bp和576 bp。构建的pIRES2-GDNF-VEGF165双基因共表达载体经Bgl II/Bam HI切出GDNF条带,经Bam HI/Not I双酶切后切出IRES-VEGF165片段,经Bgl II/Not I双酶切后切出GDNF-IRES-VEGF165片段。RT-PCR与Western-blot方法检测显示,此载体转染后,HEK293细胞均能表达人胶质细胞源性神经营养因子和血管内皮生长因子165 mRNA和蛋白。说明实验成功构建了能表达人胶质细胞源性神经营养因子和血管内皮生长因子165的双基因真核表达载体。

Construction and identification of pIRES2-GDNF-VEGF165 bicistronic eukaryotic expression vector

BACKGROUND： Human glial cell line-derived neurotrophic factor （GDNF） and vascular endothelial growth factor 165 （VEGF16s） are essential genes for cell differentiation. OBJECTIVE： To construct and identify plRES2-GDNF-VEGF165 bicistronic eukaryotic expression vector. METHODS： Human GDNF genes were obtained from the genomic DNA of human peripheral blood mononuclear cells by PCR. Then the GDNF cDNA fragment was inserted into the multiple cloning sites of ptRES2-EGFP, to generate the bicistronic eukaryotic expression ptasmid ptRES2-GDNF-EGFP. The VEGF165 gene was obtained from plRES2-VEGF165-EGFP plasmid by twin PCR. Then VEGF165 cDNA fragment was cloned into the plRES2-GDNF-EGFP, instead of EGFP, to create a double gene co-expressing vector plasmid plRES2-GDNF-VEGF~6s containing internal ribosome entry sites. Then plRES2-GDNF-VEGF165 was used to transfect HEK293 cells. RT-PCR and western blot analysis were performed to test the co-expression of double genes. RESULTS AND CONCLUSION： DNA sequencing analysis demonstrated that the GDNF and VEGF165 were exactly consistent with the sequence recorded in the GenBank. The size of GDNF gene was 636 bp and the size of VEGF165 gene was 576 bp. Enzyme digestion analysis indicated that, plRES2-GDNF-VEGF165 bicistronic eukaryotic expression vector inserted GDNF band by Bgl IIIBam HI, inserted IRES-VEGF~65 fragment by Barn HIINot 1, and inserted GDNF-IRES-VEGF165 fragment by Bgl IIINot1. RT-PCR and western blot analysis showed that, after HEK293 ceils were transfected with plRES2-GDNF-VEGF165, doubte genes were expressed at the mRNA and protein levels. The plRES2-GDNE-VEGF~ss bicistronic eukaryotic expression vector is successfully constructed.