SUMO化修饰的Apak对核糖体RNA合成的调控作用  

SUMOylation of Apak Regulates Ribosome RNA Synthesis

作　　者：杨利华[1,2] 王珊[2] 汪思应[1] 张令强[1,2] 

机构地区：[1]安徽医科大学基础医学院,合肥230001 [2]军事医学科学院放射与辐射医学研究所,北京100850

出　　处：《中国科学：生命科学》2015年第11期1117-1123,共7页Scientia Sinica(Vitae)

基　　金：国家自然科学基金(批准号:31125010;81221004);国家重点基础研究发展计划(批准号:2011CB910802;2013CB910803;2012CB910702)资助

摘　　要：核糖体是由核糖体RNA和核糖体蛋白组成的复合体,其功能是参与蛋白质合成.SUMO化修饰的底物蛋白对核糖体的形成有重要调控作用.前期研究发现,KRAB型锌指蛋白Apak能特异地抑制p53所介导的凋亡通路.进一步研究发现,在核仁应激及癌基因激活条件下,抑癌蛋白ARF促进Apak发生SUMO化修饰并促使其移位于核仁.为了进一步探讨SUMO化修饰的Apak对核糖体RNA合成的调控功能,本研究通过Northern blot检测SUMO化修饰的Apak对核糖体RNA合成的影响,实时定量PCR检测核糖体RNA转录水平,RNA-Ch IP方法检测核糖体RNA与Apak蛋白的相互作用,结果表明,SUMO化修饰的Apak抑制47S核糖体RNA前体的合成且抑制RNA聚合酶Ⅰ介导转录的18S和5.8S r RNA的合成;在放线菌素D以及癌基因诱导下,促进Apak与18S,5.8S r RNA相互作用.本研究对理解Apak的功能和作用机制提供了新的依据,为深入研究KRAB型锌指蛋白家族分子对核糖体RNA的调控奠定了基础.Ribosome is a complex consisted by ribosomal RNA and ribosomal proteins, which is required for protein synthesis. SUMOylation of substrate proteins have an important role in ribosome biogenesis. Previous studies found that the KRAB-type zinc-finger protein Apak specifically suppresses p53-mediated apoptosis. Upon ribosomal stress, the tumor suppressor protein ARF promotes Apak SUMOylation and translocation to the nucleolus. To evaluate the regulation of ribosome RNA synthesis by SUMOylation of Apak, in this study, Northern blot assay was used to detect the level of ribosome RNA to evaluate the regulation of ribosome RNA synthesis by SUMOylation of Apak. Real-time PCR detect the level of ribosome RNA transcripts. RNA-Ch IP examined the interaction between Apak and ribosomal RNA. Here we showed that SUMOylation of Apak inhibits 47 S ribosomal RNA precursor synthesis and specifically reduced 18 S r RNA and 5.8S rRNA transcribed by RNA polymerase I. Moreover, our data demonstrated the specific interaction between endogenous Apak and 18 S rRNA or 5.8S rRNA in human cells following Act D treatment and oncogenic stress. These finding provide new evidences for understanding functions of Apak in cellular process and new insights into the regulatory mechanism of KRAB type zinc finger proteins in ribosomal RNA synthesis.

关 键 词：Apak SUMO化修饰 核糖体RNA 

分 类 号：Q75[生物学—分子生物学]