Doma Meenakshi K
Division of Biology and Howard Hughes Medical Institute, California Institute of Technology, Pasadena, California, USA.
Methods Enzymol. 2008;449:3-21. doi: 10.1016/S0076-6879(08)02401-4.
In eukaryotic cells, conserved mRNA surveillance systems target and degrade aberrant mRNAs, eliminating translation errors that occur during protein synthesis and thereby imposing quality control of gene expression. Two such cytoplasmic quality control systems, nonsense-mediated mRNA decay and nonstop mRNA decay, have evolved to target mRNAs with aberrancies in translation. A third novel quality control system has been identified for yeast mRNAs with defects in translation elongation due to strong translation pause sites. This subset of mRNAs with ribosome pause sites is recognized and targeted for degradation by an endonucleolytic cleavage in a process referred to as no-go mRNA decay (NGD). The methods described herein are designed to aid in the study of NGD in Saccharomyces cerevisiae. They include procedures to create an efficient translation elongation pause, assay decay characteristics of NGD substrates, and characterize NGD-dependent endonucleolytic cleavage of mRNA. The logic of the design and methods described can be modulated and used for the identification and analysis of novel RNA quality control pathways in other organisms.
在真核细胞中,保守的mRNA监测系统会靶向并降解异常mRNA,消除蛋白质合成过程中出现的翻译错误,从而对基因表达进行质量控制。两种这样的细胞质质量控制系统,即无义介导的mRNA降解和无终止密码子mRNA降解,已经进化到可以靶向翻译过程中出现异常的mRNA。对于因强翻译暂停位点而导致翻译延伸缺陷的酵母mRNA,已经鉴定出第三种新型质量控制系统。这种带有核糖体暂停位点的mRNA子集在一个被称为无进展mRNA降解(NGD)的过程中,通过核酸内切酶切割被识别并靶向降解。本文所述的方法旨在帮助研究酿酒酵母中的NGD。它们包括创建高效翻译延伸暂停的程序、分析NGD底物的降解特征以及表征NGD依赖的mRNA核酸内切酶切割。所描述的设计逻辑和方法可以进行调整,并用于识别和分析其他生物体中的新型RNA质量控制途径。