Weiss R B, Dunn D M, Shuh M, Atkins J F, Gesteland R F
Howard Hughes Medical Institute, University of Utah School of Medicine, Salt Lake City 84132.
New Biol. 1989 Nov;1(2):159-69.
Many retroviruses express gag-pol or gag-pro-pol polypeptides by coupling their translation from overlapping reading frames with -1 ribosomal frameshifts. Here, we show that the well-known ribosomal frameshift signals found in retroviral mRNA will provoke Escherichia coli ribosomes to shift frame in the same manner as their eukaryotic counterparts. Ribosomes of E. coli respond in vivo to both the tandem slippery codons present at the retroviral frameshift site and the 3' flanking sequence. Slight alteration of the mouse mammary tumor virus gag-pro frameshift site from A-AAA-AAC to A-AAA-AAG boosts the level of frameshifting in E. coli to over 50%. This suggests that A-AAA-AAG, and its slippery relatives, may be utilized by E. coli genes as sites of high-level ribosomal frameshifting. This observed conservation of response to retroviral frameshift signals affords new avenues to dissect the mechanism of ribosomal frameshifting evoked by these mRNA sequences.
许多逆转录病毒通过将来自重叠阅读框的翻译与-1核糖体移码相结合来表达gag-pol或gag-pro-pol多肽。在此，我们表明在逆转录病毒mRNA中发现的著名核糖体移码信号会促使大肠杆菌核糖体以与真核核糖体相同的方式移码。大肠杆菌核糖体在体内对逆转录病毒移码位点处的串联滑码密码子和3'侧翼序列均有反应。小鼠乳腺肿瘤病毒gag-pro移码位点从A-AAA-AAC轻微改变为A-AAA-AAG，可将大肠杆菌中的移码水平提高到50%以上。这表明A-AAA-AAG及其滑码相关序列可能被大肠杆菌基因用作高水平核糖体移码的位点。观察到的对逆转录病毒移码信号反应的保守性为剖析这些mRNA序列引发核糖体移码的机制提供了新途径。
