Abstract：
In each round of translation elongation, the ribosome translocates along the mRNA by precisely one codon. Translocation is promoted by elongation factor G (EF-G) in bacteria (eEF2 in eukaryotes) and entails a number of precisely-timed large-scale structural rearrangements. As a rule, the movements of the ribosome, tRNAs, mRNA and EF-G are orchestrated to maintain the exact codon-wise step size. However, signals in the mRNA, as well as environmental cues, can change the timing and dynamics of the key rearrangements leading to recoding of the mRNA into production of trans-frame peptides from the same mRNA. In this review, we discuss recent advances on the mechanics of translocation and reading frame maintenance. Furthermore, we describe the mechanisms and biological relevance of non-canonical translocation pathways, such as hungry and programmed frameshifting and translational bypassing, and their link to disease and infection.
摘要：
在每一轮平移伸长中，核糖体通过恰好一个密码子沿着mRNA易位。细菌中的延伸因子G（EF-G）（真核生物中的eEF2）促进了易位，并需要许多精确定时的大规模结构重排。作为一项规则,核糖体的运动，tRNAs,协调mRNA和EF-G以保持精确的密码子步幅。然而,mRNA中的信号，以及环境线索，可以改变关键重排的时间和动力学，导致将mRNA重新编码为从相同mRNA产生反式框架肽。在这次审查中,我们讨论了移位和阅读框架维护力学的最新进展。此外，我们描述了非规范易位途径的机制和生物学相关性，例如饥饿和程序化的框架转移和翻译绕过，以及它们与疾病和感染的联系。
