Jacks T, Madhani H D, Masiarz F R, Varmus H E
Department of Biochemistry and Biophysics, University of California, San Francisco 94143.
Cell. 1988 Nov 4;55(3):447-58. doi: 10.1016/0092-8674(88)90031-1.
The gag-pol protein of Rous sarcoma virus (RSV), the precursor to the enzymes responsible for reverse transcription and integration, is expressed from two genes that lie in different translational reading frames by ribosomal frameshifting. Here, we localize the site of frameshifting and show that the frameshifting reaction is mediated by slippage of two adjacent tRNAs by a single nucleotide in the 5' direction. The gag terminator, which immediately follows the frameshift site, is not required for frameshifting. Other suspected retroviral frameshift sites mediate frameshifting when placed at the end of RSV gag. Mutations in RSV pol also affect synthesis of the gag-pol protein in vitro. The effects of these mutations best correlate with the potential to form an RNA stem-loop structure adjacent to the frameshift site. A short sequence of RSV RNA, 147 nucleotides in length, containing the frameshift site and stem-loop structure, is sufficient to direct frameshifting in a novel genetic context.
劳氏肉瘤病毒（RSV）的gag-pol蛋白是负责逆转录和整合的酶的前体，它由位于不同翻译阅读框的两个基因通过核糖体移码表达。在这里，我们定位了移码位点，并表明移码反应是由两个相邻的tRNA在5'方向上单个核苷酸的滑动介导的。紧跟移码位点的gag终止子对于移码不是必需的。当置于RSV gag末端时，其他可疑的逆转录病毒移码位点介导移码。RSV pol中的突变也会影响体外gag-pol蛋白的合成。这些突变的影响与在移码位点附近形成RNA茎环结构的潜力最相关。一段长度为147个核苷酸的RSV RNA短序列，包含移码位点和茎环结构，足以在新的遗传背景下指导移码。
