SIPAR和STAT3相互作用并对其信号通路进行负调控  

SIPAR Interacts with STAT3 and Negatively Regulates Its Activities

作　　者：宁红秀[1] 戎煜[1] 张原江[1] 任芳丽[1] 常智杰[1] 

机构地区：[1]清华大学生物科学与技术系,清华大学生命科学与医学研究院,北京100084

出　　处：《生物化学与生物物理进展》2005年第2期173-179,共7页Progress In Biochemistry and Biophysics

基　　金：国家自然科学基金资助项目(39970369;30070703) ;清华大学985资助项目.~~

摘　　要：STAT3对细胞的生长、存活、增殖以及机体的发育都具有重要的作用. STAT3基因的失活可以引起多种疾病,而STAT3基因的过度激活又可以引发很多癌症. 为了对STAT3信号通路的调控做进一步的研究,采用酵母双杂交的方法,以STAT3蛋白全长作为诱饵蛋白,筛选了小鼠7天的胚胎文库. 得到了与STAT3相互作用的一个功能未知的蛋白质,将其命名为SIPAR (Stat3 interacting protein as a repressor). 免疫染色的实验结果表明,SIPAR是一种在核内分布为主,细胞质中也有少许分布的蛋白质. 荧光酶活性测定结果表明SIPAR对STAT3的转录活性具有抑制作用. 斑马鱼注射实验说明SIPAR基因表达严重影响了斑马鱼的正常发育.STAT3 plays very important roles in cell survive, proliferation, differentiation, and transformation. Constitutively activated STAT3 was found in many cancers and tumors, including melanoma, breast cancer, head and neck cancer. In order to reveal the mechanisms of STAT3 signaling regulation, a yeast two hybrid screening using STAT3 as bait was performed in the 7days mouse cDNA library. Among the positive clones, a novel protein with 259 amino acids, named SIPAR (STAT3 interacting protein as a repressor) with a GenBank accession number AY714985, was isolated to interact with STAT3. The interaction between STAT3 and SPAR was analyzed using yeast two hybrid experiments and the functions of the interaction in STAT3 activities as a major signaling transducer was studied. The data from beta-Gal activity colony-lift filter assay and liquid assay showed that SIPAR had a strong interaction with STAT3. The Western blot experiment showed SIPAR was expressed as a 28 ku protein and a larger protein and mainly located in nucleus in mammalian cells. In order to investigate the function of SIPAR on STAT3 signal pathway, STAT3 luciferase reporter system and SIPAR expression plasmids were co-transfected into mammalian cells. The data demonstrated that when SIPAR was overexpressed, STAT3 transcription activity was inhibited dramatically. Finally, the effect of SPAR on development was investigated in zebrafish. When SPAR mRNA was injected, the zebrafish development was affected seriously with shortened body axis, which was in agreement with the experiment of inhibition of STAT3. The data suggested that SIPAR was a novel negative regulator on STAT3 activities.

关 键 词：STAT3 SIPAR 蛋白质相互作用 基因调控 

分 类 号：Q7[生物学—分子生物学]