Department of Biological Sciences, Graduate Schools of Science and Engineering, Tokyo Metropolitan University, Tokyo 192-0397, Japan.
Institute of Molecular Medicine, Medical College, National Cheng-Kung University, Tainan City 704, Taiwan; Infectious Disease and Signal Transduction Center, Medical College, National Cheng-Kung University, Tainan City 704, Taiwan.
J Mol Biol. 2015 Feb 27;427(4):955-965. doi: 10.1016/j.jmb.2014.12.013. Epub 2014 Dec 26.
Biogenesis of ribosomes is a complex process mediated by many factors. While its transcription proceeds, ribosomal RNA (rRNA) folds itself into a characteristic three-dimensional structure through interaction with ribosomal proteins, during which its ends are processed. Here, we show that the essential protein YqgF, a RuvC family protein with an RNase-H-like motif, is involved in the processing of pre-16S rRNA during ribosome maturation. Indeed, pre-16S rRNA accumulated in cells of a temperature-sensitive yqgF mutant (yqgF(ts)) cultured at a non-permissive temperature. In addition, purified YqgF was shown to process the 5' end of pre-16S rRNA within 70S ribosomes in vitro. Mass spectrometry analysis of the total proteins in the yqgF(ts) mutant cells showed that the expression of genes containing multiple Shine-Dalgarno-like sequences was observed to be lower than in wild type. These results are interpreted to indicate that YqgF is involved in a novel enzymic activity necessary for the processing of pre-16S rRNA, thereby affecting elongation of translation.
核糖体的生物发生是一个由多种因素介导的复杂过程。在转录进行的同时，核糖体 RNA（rRNA）通过与核糖体蛋白相互作用折叠成特征性的三维结构，在此过程中其末端被加工。在这里，我们表明，必需蛋白 YqgF 是一种具有 RNase-H 样基序的 RuvC 家族蛋白，参与核糖体成熟过程中前 16S rRNA 的加工。事实上，在非允许温度下培养的温度敏感 yqgF 突变体（yqgF(ts)）细胞中积累了前 16S rRNA。此外，体外纯化的 YqgF 被证明能够在 70S 核糖体中处理前 16S rRNA 的 5'端。yqgF(ts)突变体细胞中总蛋白的质谱分析表明，观察到含有多个 Shine-Dalgarno 样序列的基因的表达低于野生型。这些结果表明 YqgF 参与了前 16S rRNA 加工所必需的一种新的酶促活性，从而影响翻译的延伸。
