早幼粒白血病-维甲酸受体α融合蛋白对RIAM基因转录的负调控作用探讨  

The transcriptional downregulation of RIAM gene mediated by PML-RARα fusion protein

作　　者：赵旭杰[1] 朱雪花[1] 张济[1] 王侃侃[1] 

机构地区：[1]上海交通大学医学院附属瑞金医院医学基因组学国家重点实验室,上海200025

出　　处：《肿瘤》2012年第10期767-774,共8页Tumor

基　　金：国家自然科学基金资助项目(编号:31171257)

摘　　要：目的:研究异常转录因子早幼粒白血病-维甲酸受体α(promyelocytic leukemia-retinoic acid receptor alpha,PML-RARα)融合蛋白对RIAM基因的转录调控机制。方法:利用表达谱数据库(GSE1159)比较RIAM基因在急性髓系白血病(acute myeloid leukemia,AML)各亚型中的表达情况,以及RIAM基因和PML-RARα融合蛋白之间的相关性。采用蛋白质印迹法和实时荧光定量-PCR法分别检测PML-RARα融合蛋白和RIAM基因在急性早幼粒细胞白血病(acute promyelocytic leukemia,APL)模式细胞株PR9及APL患者来源的细胞株NB4中的表达情况,以及在全反式维甲酸(all-trans retinoicacid,ATRA)处理前后的RIAMmRNA的表达情况。利用染色质免疫沉淀技术检测细胞内PML-RARα融合蛋白在RIAM基因启动子附近的结合情况。结果:RIAM基因在APL(即M3型AML)中的表达水平明显低于其他AML亚型(M0、M1、M2、M4、M5和M7型)和正常造血细胞(P<0.05)。随着PML-RARα融合蛋白的表达,RIAM基因的表达水平明显降低。ATRA能激活RIAM基因的表达,且PML-RARα融合蛋白的表达能增强ATRA对RIAM基因表达的激活效应。PML-RARα融合蛋白结合在RIAM基因的启动子区域。结论:RIAM基因是PML-RARα融合蛋白的靶基因,PML-RARα融合蛋白通过结合到RIAM基因的启动子区域对其转录进行负调控。Objective： To investigate the effect of transcriptional regulation of aberrant transcription factor PML-RARα （promyelocytic leukemia-retinoic acid receptor alpha） on RIAM （Rap1-guanosine triphosphate-interacting adaptor molecule） gene expression in APL （acute promyelocytic leukemia）, and to explore the possible mechanism of PML-RARα fusion protein involved in occurrence, progression and treatment of APL. Methods： The expression profile of AML （acute myeloid leukemia） patients was collected by using Gene Expression Omnibus Database GSE1159 to compare the expression levels of RIAM gene in different AML subtypes and the correlation of RIAM gene and PML-RARα fusion protein. The expression levels of PML-RARα fusion protein in PR9 cells and NB4 cells with or without ATRA （all-trans retinoic acid） treatment were detected by RFQ-PCR （real-time fluorogenic quantitative-PCR）. The enrichment of ML-RARα fusion protein at the promoter region of RIAM gene was detected by ChIP （chromatin immunoprecipitation）. Results： The expression level of RIAM gene was lower in APL （M3） than in other subtypes of AML （M0, M1, M2, M4, M5 and M7） and normal hematopoietic cells （P 〈 0.05）. PML-RARα fusion protein suppressed the expression of RIAM gene. ATRA increased the expression of RIAM gene, and this effect could be enhanced by the presence of PML-RARα fusion protein which bound to the promoter region of RIAM gene. Conclusion： RIAM is a target gene for PML-RARα fusion protein which downregulates the transcription of RIAM gene by binding to the promoter region of RIAM gene.

关 键 词：白血病 早幼粒细胞 急性 调节元件 转录 融合蛋白类 PML-RARα RIAM基因 

分 类 号：R733.71[医药卫生—肿瘤]