人CD81真核表达载体的构建及在COS-7细胞中的表达

目的:构建含人CD81基因的真核表达载体,探讨CD81在COS-7细胞的表达,为研究丙型肝炎病毒(HCV)与CD81相互作用奠定基础.方法:从我们构建的含人CD81全编码基因载体pMD18-T-CD81,应用双酶切回收基因片段,定向克隆入真核表达载体pVAX1;通过脂质体介导的基因转染技术将pVAX1-CD81和空载体转入COS-7细胞;应用抗CD81单克隆抗体通过间接免疫荧光法检测COS-7细胞的表达产物.结果:重组的含CD81基因的真核表达载体pVAX1-CD81经酶切和PCR鉴定分析正确,并证明在COS-7细胞表面有效地表达CD81蛋白.结论:成功构建含CD81全编码基因的真核表达载体pVAX1-CD81,并在COS-7细胞表面有效表达CD81分子,该转染细胞可作为研究CD81在HCV感染中的作用提供模型.

小鼠AFP-CTLA4融合蛋白真核表达载体的构建及鉴定

目的:克隆小鼠甲胎蛋白(mAFP)基因并构建小鼠甲胎蛋白-细胞毒性T淋巴细胞抗原4(mAFP-CTLA4)融合蛋白真核表达载体.方法:从Hepal-6细胞中提取总RNA进行RT-PCR,扩增出mAFP基因,亚克隆于pcDNA3.1载体.PCR法从质粒pmCTLA4-Ig中克隆出mCTLA4膜外部分基因并通过重叠PCR法添加接头,重组连接于pmAFP质粒中mAFP基因后,转化大肠杆菌DH5α,筛选阳性克隆酶切、测序鉴定.用质粒瞬时转染CHO细胞,Westernblot检测融合蛋白的表达.结果:利用RT-PCR从Hepal-6细胞总RNA中成功克隆出1.8kb的nAFP基因;重组阳性克隆经酶切鉴定证实连有接头的CTLA4膜外部分基因已正确插入pmAFP质粒中,测序结果证实各片段连接方向及阅读框正确.用质粒瞬时转染CHO细胞,Western blot检测到预计大小分子量蛋白的表达.结论:mAFP-CTLA4融合蛋白真核表达载体的构建成功,为进一步研究其在肝癌免疫治疗中的作用奠定了基础.

Objective:In order to explore the radioprotective effects of the expression of hematopoietic growth factors regulated by radio-inducible promoter on radiation injury. Methods:The human FL (Flt3 ligand) cDNA and EGFP (enhanced green fluorescent protein) cDNA were linked together with IRES and then inserted into the eukaryotic expression vector pCI-Egr, which was constructed by substituting CMV promoter in pCIneo with the Egr-1 promoter (Egr-EF). The vector was transferred into human bone marrow stromal cell line HFCL by lipofectin. The transduced cell clones (HFCL/EF) had been selected by the addition of G418. The cells were exposed to γ-radiation by 60 Co source for 0.5-20Gy. The expressions of transduced cells were detected with FACS, Northern blot ELISA and CFU assay. The HFCL/EF and CD34+ cells from human umbilical cord blood were one after the other transplanted i.v. into sublethally irradiated severe combined immunodeficient (SCID) mice. The white blood cell amount in peripheral blood and human cell engrafted in recipent mice were detected by flow cytometry and CFU-GM etc. Results:The activity of EGFP in transduced cells increased by 3.1 fold as compared to non-transduced cells at 18h after exposure to 2.5Gy. The amounts of secreted FL in serum-free supernatants of Egr-EF increased by 605.46±107.21pg/ml, which were significantly higher than the control group (214.45±35.61pg/ml). The effects of FL in HFCL/EF cultural supernatants on expansion of CD34+ cells derived from cord blood in the presence of SCF, IL-6 and IL-3 were also studied. The results showed that at day 10 of culture the number of CD34+ cells increased by 173. 09±11.58×103/ml, which was significantly higher than that of non-radiation group(68. 04± 13. 73 × 103/ml). It showed that radiation can enhance the ability of the supernatants containing FL of HFCL/EF to expand early hematopoietic progenitor cells and protect hematopoietic cells from radiation-injury effects. The HFCL/EF and CD34+cells from human umbilical cord blood were one after the other transplanted i. v. into sublethally irradiated severe combined immunodeficient (SCID) mice. In contrast to two control groups (HFCL and HFCL/F), HFCL/EF (the Egr-1 regulatory element-drived expression of FL gene therapy) resulted in a proportionally obvious increase in the number of the white blood cell at early stage after radiation, while no significant differences were found for CD45+ 、CD34+ cells in bone marrow cells. In contrast to two control groups (HFCL and HFCL/F), HFCL/EF (the Egr1 regulatory element-drived expression of FL gene therapy) resulted in a proportionally obvious increase in the number of the white blood cell at early stage after radiation, without significant differences being found for CD45+、CD34+ 、CFU-GM and marrow nucleared cells in bone marrow cells. Conclusions:The results suggested both in vivo and in vitro use of the gene therapy of FL gene regulated by Egr-1 promoter could protect hematopoiesis from irradiation-induced damage.

人乳头瘤病毒6bL1双顺反子载体的构建及其在哺乳动物细胞内的表达

目的构建尖锐湿疣患者人乳头瘤病毒6b型晚期基因(HPV6b L1)的双顺反子表达载体,并使其在哺乳动物细胞内表达,以期建立含有HPV6b L1的细胞模型.方法表达质粒pEGFP-HPV6bL1经双酶切纯化后与经过相同双酶切的真核表达质粒pIRES2-EGFP连接,酶切鉴定,挑选阳性克隆进行测序.重组质粒pIRES2-HPV6bL1-EGFP转染进小鼠成纤维细胞(NIH3T3),荧光显微镜下观察EGFP蛋白的表达.RT-PCR检测HPV6b L1 mRNA的生成.结果成功构建含HPV6b L1的重组质粒pIRES2-HPV6bL1-EGFP.重组体成功转染进NIH3T3细胞,并用G418筛选.同时荧光倒置显微镜下可观察到细胞内有绿色荧光蛋白的表达.进一步进行RT-PCR,检测到HPV6b L1 mRNA的生成.结论成功构建携带HPV6b L1的重组体pIRES2-HPV6bL1-EGFP并转染入NIH3T3细胞.经荧光倒置显微镜观察及RT-PCR方法检测证明HPV6b L1在NIH3T3细胞内成功表达.