Fast-Forward Genetics Identifies Plant CPL Phosphatases as Regulators of miRNA Processing Factor HYL1.

发布者:刘冉发布时间:2012-12-28浏览次数:479

    德国马克思•普朗克发育生物学研究所的科学家在miRNA研究中获重要发现。研究者在植物中新发现CPL磷酸酶为调控成熟miRNA形成过程的关键因子,为miRNA定义了一种新的调控过程,此过程作为遗传机制的一个调控开关,能快速的适应环境的变化。相关研究11月6日在线发表在《Cell》杂志上。

  

    

    生物体成熟miRNA是通过较长的初级转录前体经一系列核酸酶的剪切加工而产生,随后组装入沉默复合体,通过碱基互补配对的方式靶向识别mRNA,抑制或降解而调控基因的表达。与动物相似,植物体中起调节miRNA的关键因素为Dicer蛋白,但其组装过程较为复杂。德国科学家开展一系列研究以确定植物体中调控miRNA成熟的关键因子。研究者通过将特异性调控的miRNA前体插入拟南芥基因片段中,以抑制已整合荧光素酶基因个体中其基因的表达。经荧光素酶活性精确检测,大部分拟南芥中未检测出荧光素酶,miRNA发挥沉默基因的效应,其中仍有少部分突变个体仍表达荧光素酶。为确定植物突变体miRNA沉默功能失效的原因,科学家采用新一代高通量全基因组测序技术,快速获得了miRNA生物活性缺陷的突变体全部基因序列,经信息学分析及蛋白组学验证分析发现由于miRNA信号通路受损,不再能够沉默荧光素酶,从而确定了磷酸酶CPL1是miRNA生物合成信号通路的一个关键元件,这一蛋白的缺失破坏了miRNA精确形成的过程。植物中的miRNAs较动物中的较为特异,这一调控miRNA过程为许多遗传调控机制其中的一种,能发育过程不断改变的需求提供了快速高效的应答。这一研究发现为植物中miRNA形成理论提供了新的定义。

   

Fast-Forward Genetics Identifies Plant CPL Phosphatases as Regulators of miRNA Processing Factor HYL1.

Cell. 2012 Nov 9;151(4):859-70. doi: 10.1016/j.cell.2012.09.039.

Abstract:MicroRNAs (miRNAs) are processed from primary transcripts that contain partially self-complementary foldbacks. As in animals, the core microprocessor in plants is a Dicer protein, DICER-LIKE1 (DCL1). Processing accuracy and strand selection is greatly enhanced through the RNA binding protein HYPONASTIC LEAVES 1 (HYL1) and the zinc finger protein SERRATE (SE). We have combined a luciferase-based genetic screen with whole-genome sequencing for rapid identification of new regulators of miRNA biogenesis and action. Among the first six mutants analyzed were three alleles of C-TERMINAL DOMAIN PHOSPHATASE-LIKE 1 (CPL1)/FIERY2 (FRY2). In the miRNA processing complex, SE functions as a scaffold to mediate CPL1 interaction with HYL1, which needs to be dephosphorylated for optimal activity. In the absence of CPL1, HYL1 dephosphorylation and hence accurate processing and strand selection from miRNA duplexes are compromised. Our findings thus define a new regulatory step in plant miRNA biogenesis.