tRNA regulation of gene expression:: Interactions of an mRNA 5′-UTR with a regulatory tRNA
tRNA regulation of gene expression:: Interactions of an mRNA 5′-UTR with a regulatory tRNA
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DOI：
10.1261/rna.29906
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发表时间：
2006-07-01
期刊：
影响因子：
4.5
通讯作者：
Agris, Paul F.
中科院分区：
文献类型：
--
作者：
Nelson, Audrey R.;Henkin, Tina M.;Agris, Paul F.
在革兰氏阳性菌中，许多编码氨基酰-tRNA合成酶和其他氨基酸相关产物的基因，包括重要的病原体，都是通过未酰化的tRNA与mRNA的5‘-非翻译区(5’-UTR)相互作用来调节的。受这一机制调控的每个基因都对同源tRNA产生特异性反应，特异性由tRNA的反密码子与5‘-UTR的“指定环”中的密码子序列配对确定。为了使5‘-UTR在基因调控中发挥作用，mRNA的折叠相互作用必须足够稳定，以提供与匹配的tRNA的反密码子产生结合的密码子序列。建立了一个模型双分子系统，其中两个半分子(“公共”和“特定子”)之间的相互作用将重组枯草杆菌lyqS基因5‘-非编码区的特定子环区，编码GlyRS mRNA。凝胶迁移率漂移分析和荧光光谱分析分别得到普通半分子和特殊半分子形成络合物的实验K(D)S为27.6+/-1.0µM和10.5+/-60.7µM。重组的GlyQS基因5‘-非编码区与tRNA-Gly(ASL-Gly-GCC)的反密码子茎和环特异结合，具有显著的亲和力(K-d=20.2+/-61.4mM)。因此，双分子5‘-UTR和Asl(GCC)(Gly)模型模拟了体内T盒基因调控所需的RNARNA相互作用。
Many genes encoding aminoacyl-tRNA synthetases and other amino acid-related products in Gram-positive bacteria, including important pathogens, are regulated through interaction of unacylated tRNA with the 5'-untranslated region (5'-UTR) of the mRNA. Each gene regulated by this mechanism responds specifically to the cognate tRNA, and specificity is determined by pairing of the anticodon of the tRNA with a codon sequence in the "Specifier Loop'' of the 5'-UTR. For the 5'-UTR to function in gene regulation, the mRNA folding interactions must be sufficiently stable to present the codon sequence for productive binding to the anticodon of the matching tRNA. A model bimolecular system was developed in which the interaction between two half molecules ("Common'' and "Specifier'') would reconstitute the Specifier Loop region of the 5'-UTR of the Bacillus subtilis glyQS gene, encoding GlyRS mRNA. Gel mobility shift analysis and fluorescence spectroscopy yielded experimental K(d)s of 27.6 +/- 1.0 mu M and 10.5 +/- 6 0.7 mu M, respectively, for complex formation between Common and Specifier half molecules. The reconstituted 5'-UTR of the glyQS mRNA bound the anticodon stem and loop of tRNA Gly (ASL Gly GCC) specifically and with a significant affinity (K-d = 20.2 +/- 6 1.4 mu M). Thus, the bimolecular 5'-UTR and ASL(GCC)(Gly) models mimic the RNA-RNA interaction required for T box gene regulation in vivo.