Amrani Nadia, Sachs Matthew S, Jacobson Allan
Department of Molecular Genetics and Microbiology, University of Massachusetts Medical School, Worcester, Massachusetts 01655-0122, USA.
Nat Rev Mol Cell Biol. 2006 Jun;7(6):415-25. doi: 10.1038/nrm1942.
Gene expression is highly accurate and rarely generates defective proteins. Several mechanisms ensure this fidelity, including specialized surveillance pathways that rid the cell of mRNAs that are incompletely processed or that lack complete open reading frames. One such mechanism, nonsense-mediated mRNA decay, is triggered when ribosomes encounter a premature translation-termination--or nonsense--codon. New evidence indicates that the specialized factors that are recruited for this process not only promote rapid mRNA degradation, but are also required to resolve a poorly dissociable termination complex.
基因表达高度精确，很少产生有缺陷的蛋白质。有几种机制确保了这种保真度，包括专门的监测途径，这些途径可清除细胞中未完全加工或缺乏完整开放阅读框的mRNA。其中一种机制，即无义介导的mRNA降解，是在核糖体遇到提前的翻译终止密码子（即无义密码子）时触发的。新证据表明，为此过程招募的专门因子不仅促进mRNA的快速降解，而且对于解决难以解离的终止复合物也是必需的。
