Bossi L, Smith D M
Proc Natl Acad Sci U S A. 1984 Oct;81(19):6105-9. doi: 10.1073/pnas.81.19.6105.
We describe the DNA sequence change responsible for the creation of a frameshift-suppressor gene in Salmonella typhimurium. The suppressor, sufJ, results from a base-pair insertion in the gene coding for a threonine transfer RNA (tRNA3Thr). Unlike previously studied frameshift suppressor mutations, the sufJ insertion does not fall within the sequence corresponding to the tRNA anticodon. The insertion (a G.C base pair) occurs within a run of three G.C base pairs in that region of the gene coding for one strand of the anticodon stem. In the secondary structure of the mature tRNA, the net result is that an extra, unpaired cytidine residue is pushed into the anticodon loop, thus increasing the size of the loop to eight nucleotides. These findings are discussed in connection with the peculiar "three-out-of-four" method of reading by the sufJ suppressor. A unifying model is presented accounting for the contrasting decoding behaviors of tRNAs with eight-nucleotide-long anticodon loops.
我们描述了导致鼠伤寒沙门氏菌中移码抑制基因产生的DNA序列变化。这种抑制基因sufJ是由编码苏氨酸转运RNA（tRNA3Thr）的基因中的一个碱基对插入所导致的。与之前研究的移码抑制突变不同，sufJ插入并不位于对应于tRNA反密码子的序列内。该插入（一个G.C碱基对）发生在编码反密码子茎一条链的基因区域中的三个G.C碱基对的连续序列内。在成熟tRNA的二级结构中，最终结果是一个额外的未配对胞嘧啶残基被挤入反密码子环，从而使环的大小增加到八个核苷酸。结合sufJ抑制基因独特的“四选三”读取方式对这些发现进行了讨论。提出了一个统一模型，解释具有八个核苷酸长反密码子环的tRNA的对比解码行为。
