Ling Roger, Firth Andrew E
Division of Virology, Department of Pathology, University of Cambridge, Cambridge CB2 1QP, UK.
J Gen Virol. 2017 Aug;98(8):2100-2105. doi: 10.1099/jgv.0.000888. Epub 2017 Aug 8.
Programmed -1 ribosomal frameshifting is a mechanism of gene expression whereby specific signals within messenger RNAs direct a proportion of ribosomes to shift -1 nt and continue translating in the new reading frame. Such frameshifting normally depends on an RNA structure stimulator 3'-adjacent to a 'slippery' heptanucleotide shift site sequence. Recently we identified an unusual frameshifting mechanism in encephalomyocarditis virus, where the stimulator involves a trans-acting virus protein. Thus, in contrast to other examples of -1 frameshifting, the efficiency of frameshifting in encephalomyocarditis virus is best studied in the context of virus infection. Here we use metabolic labelling to analyse the frameshifting efficiency of wild-type and mutant viruses. Confirming previous results, frameshifting depends on a G_GUU_UUU shift site sequence and a 3'-adjacent stem-loop structure, but is not appreciably affected by the 'StopGo' sequence present ~30 nt upstream. At late timepoints, frameshifting was estimated to be 46-76 % efficient.
程序性-1核糖体移码是一种基因表达机制，信使核糖核酸（mRNA）中的特定信号可引导一部分核糖体移动-1个核苷酸，并在新的阅读框中继续翻译。这种移码通常依赖于一个位于“滑溜”七核苷酸移码位点序列3'端相邻的RNA结构刺激元件。最近，我们在脑心肌炎病毒中发现了一种不同寻常的移码机制，其中刺激元件涉及一种反式作用病毒蛋白。因此，与其他-1移码的例子不同，脑心肌炎病毒中的移码效率最好在病毒感染的背景下进行研究。在这里，我们使用代谢标记法来分析野生型和突变型病毒的移码效率。正如之前的结果所证实的，移码依赖于G_GUU_UUU移码位点序列和一个3'端相邻的茎环结构，但不受上游约30 nt处存在的“StopGo”序列的明显影响。在晚期时间点，移码效率估计为46-76%。
