目的研究HIV-1载体中的一些元件如Rev和Tat蛋白对其骨架的转录及外源基因表达水平的影响。方法将HIV-1表达GFP载体(FUGW)单独或分别与Rev蛋白表达质粒(pLP2)、Tat蛋白表达质粒(pcDNA3.1-Tat),及表达Rev和Tat蛋白的质粒(△8.9)等摩尔共转染人293T细胞后,经实时定量RT-PCR、FACS、荧光显微镜镜检等方法检测,比较其表达量。结果Rev与RRE结合后,载体骨架及外源基因的转录是单独转染FUGW时的3倍,Tat与TAR结合后,则提高其骨架及外源基因的转录近4倍,而Rev和Tat蛋白的协同作用,其转录本则可提高至6倍。FACS和荧光显微镜镜检也显示GFP蛋白表达量明显提高。F-TPO载体(HIV-1载体乳腺特异表达促血小板生成素)与△8.9在小鼠乳腺上皮细胞HC-11共转染和表达,则TPO蛋白的表达量接近pcDNA3.1-TPO载体的8倍。结论HIV-1载体中存在着提高转录和翻译基因的元件,可提高其骨架的转录和外源基因的表达,且该现象并不依赖于细胞类型和外源基因的种类。
Objective To study the impact of some HIV-1 vector elements, like Rev and Tat protein, on its backbone transcription and transgene expression. Methods We transfected HIV-1 vector containing GFP expression cassette, either alone, or together with rev plasmid (pLP2), tat plasmid (pcDNA3.1-Tat), or rev and tat plasmid (△8.9), into 293T cells, and detected the backbone transcription and GFP expression by real time RT-PCR, FACS and fluorescence micro- scope respectively. Results The transcription was enhanced to 3-fold in the case of co-transfection with pLP2, 4-fold with pcDNA3.1-Tat, and 6-fold with A8.9. GFP expression was also significantly enhanced as assessed by FACS and fluorescence microscopic observation. Moreover, the con- tent of thrombopoietin (TPO) protein in HC-11 cell culture, a murine mammary epithelial cell line, after co-transfection of HIV-1 expressing TPO vector (F-TPO) with △8.9, was nearly seven times higher than its negative control, as determined by ELISA. Conclusion Therefore, we pro- pose that some elements in HIV-1 vector as described here are able to enhance transcription and translation, which is independent of cell types and transgenes.