中文摘要：

目的：探讨HIV-1Tat蛋白对DNA修复基因及细胞周期相关基因表达影响。方法：使用包含102个与DNA损伤修复和细胞周期相关的基因微阵列检测人横纹肌肉瘤细胞（TE671）及已转染tat基因的TE671细胞（TT2）基因表达谱的改变；使用半定量RT—PCR分析DNA-PKcs在mRNA水平表达；Western印迹法检测DNA-PKcs表达变化；荧光染色法检测电离辐射后细胞凋亡。结果：在基因芯片的检测中，发现与DNA损伤修复及细胞周期调控相关的6个基因CdC25C、KIF2C、CdC20、DNA-PKcs、CTS1、WEE1在转染tal基因的细胞中表达下调；DNA-PKcs的表达在表达Tat蛋白细胞中不论是在mRNA和蛋白水平均被抑制；接受电离辐射后，表达Tat蛋白的细胞凋亡增加。结论：HIV-1 Tat蛋白使细胞对电离辐射敏感，部分通过抑制DNA-PKcs表达来降低DNA双链断裂的修复能力，本研究为了解AIDS合并肿瘤患者对放射治疗敏感性提供了重要实验数据。

英文摘要：

Objective： To explore effects of HIV - I Tat protein on expression of DNA repair genes and cell cycle related genes. Methods ： A human rhabdomyosarcoma cell lines TE671 and TI＇2 cells transfected with tat gene of the HIV - 1 strain were employed in this study. Microarray, which contains the oligonueleotide probes corresponding to 102 human DNA repair genes and cell cycle - related genes, was used to analyze the changes of gene expression in above two cell lines. The DNA - PKcs expression on mRNA and protein level was analyzed by RT - PCR and Western blot, respectively;the extent of apoptosis induced by ionizing radiation in Tat - expressing cells was detected by fluorescence staining. Results： Microarray assay demonstrated that cell cycle related genes CdC25C, KIF2C, CdC20, DNA - PKes, CTS1 and WEE1 were down - regulated in Tat - expressing TI＇2 cells;DNA - PKcs expression was inhibited whether on mRNA or on protein level. Furthermore, the extent of apoptosis induced by ionizing radiation in Tat - expressing cells was significantly higher than that in control cells. Conclusion ： HIV - 1 Tat protein may sensitize cells to ionizing radiation via at least partially depressing DNA - PKcs expression to lower repair ability of a cell following DNA double - strand break. Dysregulated cell cycle checkpoint in Tat - expressing cells could provide new information to understand the radiation responsiveness of AIDS patients with cancer to radiotherapy.