Doma Meenakshi K, Parker Roy
Howard Hughes Medical Institute, Department of Molecular and Cellular Biology, University of Arizona, Tucson, Arizona 85721, USA.
Nature. 2006 Mar 23;440(7083):561-4. doi: 10.1038/nature04530.
A fundamental aspect of the biogenesis and function of eukaryotic messenger RNA is the quality control systems that recognize and degrade non-functional mRNAs. Eukaryotic mRNAs where translation termination occurs too soon (nonsense-mediated decay) or fails to occur (non-stop decay) are rapidly degraded. We show that yeast mRNAs with stalls in translation elongation are recognized and targeted for endonucleolytic cleavage, referred to as 'no-go decay'. The cleavage triggered by no-go decay is dependent on translation and involves Dom34p and Hbs1p. Dom34p and Hbs1p are similar to the translation termination factors eRF1 and eRF3 (refs 3, 4), indicating that these proteins might function in recognizing the stalled ribosome and triggering endonucleolytic cleavage. No-go decay provides a mechanism for clearing the cell of stalled translation elongation complexes, which could occur as a result of damaged mRNAs or ribosomes, or as a mechanism of post-transcriptional control.
真核生物信使核糖核酸(mRNA)生物合成及功能的一个基本方面是识别并降解无功能mRNA的质量控制系统。翻译提前终止(无义介导的mRNA降解)或未能终止(无终止密码子的mRNA降解)的真核生物mRNA会迅速被降解。我们发现,翻译延伸过程中出现停滞的酵母mRNA会被识别并靶向进行核酸内切酶切割,即“停滞介导的降解”。停滞介导的降解引发的切割依赖于翻译过程,且涉及Dom34p和Hbs1p。Dom34p和Hbs1p与翻译终止因子eRF1和eRF3相似(参考文献3、4),这表明这些蛋白质可能在识别停滞的核糖体及触发核酸内切酶切割中发挥作用。停滞介导的降解为清除细胞内停滞的翻译延伸复合物提供了一种机制,这种复合物可能因受损的mRNA或核糖体而出现,或者作为一种转录后调控机制。