Springer M, Trudel M, Graffe M, Plumbridge J, Fayat G, Mayaux J F, Sacerdot C, Blanquet S, Grunberg-Manago M
J Mol Biol. 1983 Dec 15;171(3):263-79. doi: 10.1016/0022-2836(83)90093-1.
The two subunits of phenylalanyl-tRNA synthetase are made from two adjacent, cotranscribed genes that constitute the pheS,T operon. Three different fusions between pheS,T and lac genes were constructed in order to study the regulation of the pheS,T operon in vivo. We show, using these fusions, that phenylalanyl-tRNA synthetase transcription is derepressed when the level of aminoacylated tRNAPhe is lowered by mutational alteration of the synthetase. The pheS,T operon is also derepressed in strains carrying a trpX mutation. The gene trpX codes for an enzyme that modifies both tRNATrp and tRNAPhe and a mutation in that gene causes derepression of the trp and pheA operons, both of which are controlled by attenuation. The in vivo features of the regulation of pheS,T expression described here in correlation with the DNA sequence and in vitro transcription results described in the accompanying paper by Fayat et al. indicate that phenylalanyl-tRNA synthetase is controlled by attenuation in a way analogous to several amino acid biosynthetic operons.
苯丙氨酰 - tRNA合成酶的两个亚基由两个相邻的、共转录的基因编码，这两个基因构成了pheS,T操纵子。为了在体内研究pheS,T操纵子的调控，构建了pheS,T与lac基因之间的三种不同融合体。我们利用这些融合体表明，当通过合成酶的突变改变使氨酰化tRNAPhe水平降低时，苯丙氨酰 - tRNA合成酶的转录会去阻遏。在携带trpX突变的菌株中，pheS,T操纵子也会去阻遏。trpX基因编码一种修饰tRNATrp和tRNAPhe的酶，该基因中的突变会导致trp和pheA操纵子的去阻遏，这两个操纵子均受衰减作用控制。本文描述的pheS,T表达调控的体内特征与Fayat等人在随附论文中描述的DNA序列和体外转录结果相关，表明苯丙氨酰 - tRNA合成酶以类似于几个氨基酸生物合成操纵子的方式受衰减作用控制。
