KSHV RTA上调宿主细胞Bcl-2表达的分子机制研究  

Molecular mechanism of upregulation of cellular Bcl-2 by the KSHV encoded RTA

作　　者：高建明[1] Erle S.Robertson 

机构地区：[1]三峡大学医学院病理生理学教研室,湖北宜昌443002 [2]美国宾夕法尼亚大学医学院微生物学教研室,宾夕法尼亚费城19104

出　　处：《中国当代医药》2012年第30期12-15,共4页China Modern Medicine

基　　金：National Cancer Institute 5R01CA091792-08;5R01CA108461-05;1R01CA137894-01 and 1R01CA138434-01A209;National Institute of Allergy and Infectious Diseases 5R01AI067037-04;National Institute of Dental and Craniofacial Research 5R01DE017338-03(to ESR)

摘　　要：目的研究卡波氏肉瘤病毒(Kaposis's Sarcoma-Associated Herpesvirus,KSHV)编码的复制转录激活因子(replication and transcription activator,RTA)调控宿主细胞Bcl-2表达的分子机制。方法用实时聚合酶链反应(RT-PCR)、蛋白质印迹(Western blot)技术检测RTA转染的细胞、TPA诱导的KSHV阳性细胞Bcl-2 mRNA和蛋白质表达水平;采用PCR定点突变和荧光素酶报告基因技术,检测RTA对Bcl-2基因启动子活性的调节,并鉴定启动子序列中对RTA调控具有重要作用的顺式反应元件。结果 RTA转染的细胞、TPA诱导的KSHV阳性细胞Bcl-2 mRNA和蛋白质表达水平显著增高。RTA通过与Bcl-2基因启动子中CCN9GG反应元件结合激活Bcl-2的转录,这种激活作用呈剂量依赖性,并且P2启动子对RTA反式激活Bcl-2基因不可或缺。结论 KSHVRTA能够上调宿主细胞Bcl-2表达,CCN9GG样RTA反应元件和P2启动子对RTA调控Bcl-2表达具有重要作用。Objective To explore the molecular mechanism and biological significance of upregulation of cellular Bcl-2 by the KSHV （Kaposis＇s Sarcoma-Associated Herpesvirus） encoded RTA （replication and transcription activator）.Methods The mRNA and protein levels of Bcl-2 in RTA-transfected 293,DG75 cells and TPA-induced KSHV positive cells were analyzed by RT-PCR and Western blot.Regulation of the Bcl-2 promoter activity by RTA was investigated,and the improtant cis-acting elements within the Bcl-2 gene promoter were identified by PCR site-directed mutation and luciferase assay.Results RTA upregulated the mRNA and protein levels of Bcl-2 in RTA-expressing 293,DG75 cells and TPA-induced KSHV positive cells.Further analysis revealed that the upregulation of cellular Bcl-2 promoter by RTA was dose-dependent and acts through targeting of the CCN9GG motifs within the Bcl-2 promoter.The Bcl-2 P2 but not the P1 promoter was primarily responsive to RTA.Conclusion KSHV RTA can upregulate the expression of cellular Bcl-2,and the CCN9GG RTA responsive elements and P2 promoter are impotant for RTA-mediated upregulation of Bcl-2.

关 键 词：卡波氏肉瘤病毒 复制转录激活因子 Bcl-2 表达上调 启动子活性 

分 类 号：R392.1[医药卫生—免疫学]