Romby P, Moine H, Lesage P, Graffe M, Dondon J, Ebel J P, Grunberg-Manago M, Ehresmann B, Ehresmann C, Springer M
Institut de Biologie Moléculaire et Cellulaire du CNRS, Strasbourg, France.
Biochimie. 1990 Jun-Jul;72(6-7):485-94. doi: 10.1016/0300-9084(90)90072-o.
The expression of the gene for threonyl-tRNA synthetase (thrS) has previously been shown as being negatively autoregulated at the translational level. The region of the thrS leader mRNA responsible for that control is located immediately upstream of the ribosomal binding site, and was proposed to fold in a tRNA(Thr) anticodon arm-like structure. The present paper reviews experiments using enzymatic and chemical probes that prove the existence of a tRNA(Thr) anticodon-like structure in the thrS mRNA. These structural studies have also shown the presence of another arm upstream in the leader mRNA that has striking similarities with the acceptor arm of the tRNA(Thr) isoacceptors. This second arm was shown, by mutational analysis, to also be involved in thrS regulation. Footprinting experiments have shown that both the anticodon-like and the acceptor-like arms interact with the synthetase. Finally, the similarity of the interaction of the synthetase with its 2 RNA ligands (mRNA and tRNA) has been investigated by selecting and studying mutants of the synthetase itself. The observed correlation between regulatory and aminoacylation defects in these mutants strongly suggests that the synthetase recognizes similar regions of its 2 RNA ligands in an analogous manner.
苏氨酰 - tRNA合成酶（thrS）基因的表达先前已表明在翻译水平上受到负向自动调控。thrS前导mRNA中负责该调控的区域位于核糖体结合位点的紧邻上游，并且被认为折叠成类似tRNA（Thr）反密码子臂的结构。本文综述了使用酶学和化学探针进行的实验，这些实验证明了thrS mRNA中存在类似tRNA（Thr）反密码子的结构。这些结构研究还表明，在前导mRNA的上游存在另一个臂，它与tRNA（Thr）同工受体的接受臂有显著相似性。通过突变分析表明，这第二个臂也参与thrS的调控。足迹实验表明，类似反密码子的臂和类似接受臂的结构都与合成酶相互作用。最后，通过选择和研究合成酶本身的突变体，研究了合成酶与其两种RNA配体（mRNA和tRNA）相互作用的相似性。在这些突变体中观察到的调控缺陷和氨酰化缺陷之间的相关性强烈表明，合成酶以类似的方式识别其两种RNA配体的相似区域。
