去帽蛋白增强子Edc1p和Edc2p可结合RNA并刺激去帽酶的活性。
The enhancer of decapping proteins, Edc1p and Edc2p, bind RNA and stimulate the activity of the decapping enzyme.
作者信息
Schwartz David, Decker Carolyn J, Parker Roy
机构信息
Department of Molecular and Cellular Biology and Howard Hughes Medical Institute, University of Arizona, 1007 E. Lowell Street, Tucson, AZ 85704, USA.
出版信息
RNA. 2003 Feb;9(2):239-51. doi: 10.1261/rna.2171203.
A major pathway of eukaryotic mRNA turnover initiates with deadenylation, which allows a decapping reaction leading to 5'-3' exonucleolytic degradation. A key control point in this pathway is the decapping of the mRNA. Two proteins, Edc1 and Edc2, were genetically identified previously as enhancers of the decapping reaction. In this work, we demonstrate that Edc1p and Edc2p are RNA-binding proteins. In addition, recombinant Edc1p or Edc2p stimulates mRNA decapping in cell-free extracts or with purified decapping enzyme. These results suggest that Edc1p and Edc2p activate decapping directly by binding to the mRNA substrate and enhancing the activity of the decapping enzyme. Interestingly, edc1Delta strains show defects in utilization of glycerol as a carbon source and misregulation of several mRNAs in response to carbon-source changes. This identifies a critical role for decapping and Edc1p in alterations of gene expression in response to carbon-source changes.
真核生物mRNA周转的一条主要途径始于去腺苷酸化，这会引发脱帽反应，进而导致5'-3'核酸外切酶降解。该途径中的一个关键控制点是mRNA的脱帽。此前通过遗传学方法鉴定出两种蛋白质Edc1和Edc2是脱帽反应的增强子。在这项研究中，我们证明Edc1p和Edc2p是RNA结合蛋白。此外，重组的Edc1p或Edc2p在无细胞提取物中或与纯化的脱帽酶一起使用时，能刺激mRNA脱帽。这些结果表明，Edc1p和Edc2p通过与mRNA底物结合并增强脱帽酶的活性来直接激活脱帽。有趣的是，edc1Δ菌株在利用甘油作为碳源方面存在缺陷，并且在响应碳源变化时，几种mRNA的调控出现异常。这确定了脱帽和Edc1p在响应碳源变化时基因表达改变中的关键作用。
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