干扰素α调控维甲酸诱导基因G表达分子机制的新发现  

A novel molecular mechanism of interferon α-regulated expression of retinoic acid-induced gene G

作　　者：楼叶江[1] 潘晓蓉[1] 贾培敏[1] 李冬[2] 张长林[1] 许桂平[1] 童建华[1] 

机构地区：[1]上海交通大学医学院附属瑞金医院上海血液学研究所,200025 [2]同济大学附属同济医院检验科

出　　处：《中华肿瘤杂志》2010年第2期88-92,共5页Chinese Journal of Oncology

基　　金：基金项目：国家自然科学基金（30570778,30670882）;国家863计划（2006AA02219A）;上海市人才发展基金

摘　　要：目的探讨干扰素α（IFN-α）调控维甲酸诱导基因G（RIG-G）表达调控的分子机制。方法采用Westernblot方法检测急性早幼粒白血病细胞系NB4经IFN-α处理后信号传导和转录活化因子1（STAT1）、p-STATI和RIG—G蛋白的表达变化。采用细胞转染、报告基因实验、免疫共沉淀实验和染色质免疫沉淀实验等技术，研究STAT1缺失的U3A细胞中，STAT1、STAT2和IFN调节因子9（IRF-9）在IFN-α调控RIG—G基因表达中的作用及其机制。结果在U3A细胞中，只有当STAT2和IRF-9共同转染时，RIG—G启动子荧光素酶报告基因的表达活性才明显升高，约为空载对照组的8倍。在无IFN-α作用时，野生型或突变型STAT2与IRF-9共同转染U3A细胞可产生相似的效应；但IFN-α能进一步增强野生型STAT2与IRF-9的转录激活作用，约为未加IFN-α时的6倍，而对突变型STAT2无效。STAT2能与IRF-9相互作用，并能与RIG-G基因的启动子结合。结论STAT2和IRF-9能以不依赖于STATl的形式发生相互作用，所形成的复合物是介导IFN-α调控RIG—G基因表达的关键性转录因子，这是一种有别于经典JAK—STAT途径的新的干扰素信号转导方式。Objective To investigate the molecular mechanisms by which IFN-α regulated retinoic acid-induced gene G （RIG-G） expression. Methods The expression of STAT1, p-STAT1 and RIG-G in IFN-α-treated NB4 cells was detected by Western blot. The roles of STAT1, STAT2 and IRF-9 in IFN-α- induced RIG-G expression were analyzed in STAT1-null U3A cells by cell transfection, reporter gene assay, co-immunoprecipitation and ehromatin immunoprecipitaion. Results In U3A cells, only when STAT2 and IRF-9 were co-transfected, the luciferase activities of RIG-G promoter-containing reporter gene could be highly increased about 8-fold compared with that in the control group. Moreover, in the absence of IFN-α, similar effects were observed in either IRF-9 co-transfected with wild type or mutant form of STAT2, whereas IFN-α could increase the transactivation activity of wild type STAT2 and IRF-9 by 6-fold compared with that without IFN-α, but had no effect on mutant STAT2. In addition, STAT2 could interact with IRF-9 and bind to the RIG-G promoter. Conclusion STAT2 may interact with IRF-9 in a STATl-independent manner. The complex STAT2/IRF-9 is the key factor mediating the expression of RIG-G gene regulated by IFN-α. This is a novel signal transduction cascade for IFN which is different from the classical JAK-STAT pathway.

关 键 词：干扰素Α 信号转导 维甲酸诱导基因G 

分 类 号：R733.7[医药卫生—肿瘤]