表达HIV Vpr细胞株的建立及其促细胞凋亡作用的研究

目的 建立稳定表达人免疫缺陷病毒(HIV)Vpr蛋白的细胞株,观察Vpr蛋白促进感染细胞凋亡的特性,以及Vpr变异后对其致凋亡作用的影响.方法 以携带野生株HIV Vpr基因和突变株HIV vpr-FS基因的质粒分别转染HeLa细胞,建立稳定表达HIV Vpr蛋白的细胞株,以流式细胞仪和细胞内DNA片段分析法检测细胞凋亡效果,观察Vpr蛋白促细胞凋亡的特性,以及两者致凋亡作用的区别.结果 重组质粒pcDNA3.1-vpr和pcDNA3.1-vpr-FS经酶切后均可获得342bp产物,DNA测序结果与目的 基因已知序列完全一致;上述质粒转染的HeLa细胞,RT-PCR检测到目的 基因vpr或vpr-FS的表达,Western blot检测到明显Vpr或Vpr-FS蛋白的表达.流式细胞仪和细胞内DNA片段分析法分别检测细胞凋亡,显示野生株HeLa pcDNA3.1-vpr组的凋亡率明显高于对照组,而变异株HeLa pcDNA3.1-vpr-FS的凋亡率与对照组无明显差别.结论 成功建立了表达HIV Vpr和HIVVpr-FS蛋白的感染细胞株.实验显示HIV Vpr蛋白能促进感染细胞的凋亡,而Vpr蛋白的变异可能使其促进细胞凋亡作用减弱.实验结果为下一步研究提供了基础资料.

The establishment of a cell strain expressing HIV Vpr and the study on Vpr induced apoptosis

Objective To establish cell strain expressing the genes of HIV vpr and mutant HIV vpr-FS, and to explore cell apoptosis ability by HIV Vpr and Vpr-FS. Methods The recombinant plasmids were constructed by cloning HIV vpr and HIV vpr-FS genes into the eukaryotic expression vector pcDNA3.1respectively. To determine the primary structures of HIV vpr and HIV vpr-FS, plasmids were cleaved by restriction enzymes. After the plasmids were transfected into HeLa cells by liposome, the HeLa cells were selected with G418 selective medium, mRNA expression of HIV vpr or HIV vpr-FS of transfected cells was detected by RT-PCR, and Vpr and Vpr-FS protein expression were detected by Western blot assay respectively. The DNA content and the percentage of apoptosis in HeLa HIV vpr cell, HeLa HIV vpr-FS cell and HeLa pcDNA3.1 cell were monitored by flow cytometry and the DNA fragmentation was analyzed by agarose gel electrophoresis. Results BamH Ⅰ and Hind Ⅲ cleavaged products of pcDNA3.1-vpr and pcDNA3.1-vpr-Fincluded 342 bp length fragments suggesting that the length of DNA sequence containing HIV vpr (HIV vpr-FS) within pcDNA3.1 was the same as theoretical length. The HeLa cells transfected by pcDNA3.1-vpr or pcDNA3, l-vpr-FS and selected with G418 could express HIV vpr or HIV vpr-FS by RT-PCR, and express HIV Vpr or HIV Vpr-FS protein by Western blot. The results of flow cytometry and DNA fragmentation showed that there was significant different in the number of apoptotic cells between HeLa HIV vpr cell and HeLa HIV vpr-FS cell, but the difference between HeLa HIV vpr-FS cell and control group was not obvious. Conclusion Recombinant plasmids pcDNA3.1-vpr and pcDNA3. 1-vpr-FS were constructed successfully, and the cell strain expressing HIV Vpr and HIV Vpr-FS proteins was established. The HIV Vpr could induce host cell apoptosis, while the mutant of Vpr did not or weakened this ability. This study provides foundation for further study on HIV vpr gene.