Tucker M, Parker R
Department of Molecular and Cellular Biology and Howard Hughes Medical Institute, University of Arizona, Tucson, Arizona 85721, USA.
Annu Rev Biochem. 2000;69:571-95. doi: 10.1146/annurev.biochem.69.1.571.
The process of mRNA turnover is a critical component of the regulation of gene expression. In the past few years a discrete set of pathways for the degradation of polyadenylated mRNAs in eukaryotic cells have been described. A major pathway of mRNA degradation in yeast occurs by deadenylation of the mRNA, which leads to a decapping reaction, thereby exposing the mRNA to rapid 5' to 3' exonucleolytic degradation. A critical step in this pathway is decapping, since it effectively terminates the existence of the mRNA and is the site of numerous control inputs. In this review, we discuss the properties of the decapping enzyme and how its activity is regulated to give rise to differential mRNA turnover. A key point is that decapping appears to be controlled by access of the enzyme to the cap structure in a competition with the translation initiation complex. Strikingly, several proteins required for mRNA decapping show interactions with the translation machinery and suggest possible mechanisms for the triggering of mRNA decapping.
mRNA 周转过程是基因表达调控的关键组成部分。在过去几年里，已经描述了真核细胞中多聚腺苷酸化 mRNA 降解的一系列离散途径。酵母中 mRNA 降解的主要途径是通过 mRNA 的去腺苷酸化，这会导致脱帽反应，从而使 mRNA 暴露于快速的 5' 到 3' 核酸外切酶降解。该途径中的一个关键步骤是脱帽，因为它有效地终止了 mRNA 的存在，并且是众多控制输入的位点。在本综述中，我们讨论了脱帽酶的特性以及其活性如何被调节以产生不同的 mRNA 周转。一个关键点是，脱帽似乎是由酶与翻译起始复合物竞争进入帽结构所控制的。引人注目的是，mRNA 脱帽所需的几种蛋白质显示出与翻译机制的相互作用，并暗示了触发 mRNA 脱帽的可能机制。
