Department of Chemistry, Brown University, 324 Brook St., Providence, RI 02912, USA.
J Bacteriol. 2010 Jul;192(14):3565-73. doi: 10.1128/JB.00290-10. Epub 2010 May 7.
cis-Acting RNA elements in the leaders of bacterial mRNA often regulate gene transcription, especially in the context of amino acid metabolism. We determined that the transcription of the auxiliary, antibiotic-resistant tryptophanyl-tRNA synthetase gene (trpRS1) in Streptomyces coelicolor is regulated by a ribosome-mediated attenuator in the 5' leader of its mRNA region. This regulatory element controls gene transcription in response to the physiological effects of indolmycin and chuangxinmycin, two antibiotics that inhibit bacterial tryptophanyl-tRNA synthetases. By mining streptomycete genome sequences, we found several orthologs of trpRS1 that share this regulatory element; we predict that they are regulated in a similar fashion. The validity of this prediction was established through the analysis of a trpRS1 ortholog (SAV4725) in Streptomyces avermitilis. We conclude that the trpRS1 locus is a widely distributed and self-regulating antibiotic resistance cassette. This study provides insights into how auxiliary aminoacyl-tRNA synthetase genes are regulated in bacteria.
细菌 mRNA 前导区中的顺式作用 RNA 元件通常调节基因转录，尤其是在氨基酸代谢的情况下。我们发现，链霉菌色氨酸-tRNA 合成酶基因（trpRS1）的转录受其 mRNA 区域 5' 前导区中核糖体介导的衰减子调控。该调节元件可响应吲哚霉素和创新霉素这两种抑制细菌色氨酰-tRNA 合成酶的抗生素的生理效应来控制基因转录。通过挖掘链霉菌基因组序列，我们发现了几个具有这种调节元件的 trpRS1 同源基因；我们预测它们以类似的方式受到调控。通过对链霉菌avermitilis 中的 trpRS1 同源基因（SAV4725）的分析，验证了这一预测。我们的结论是，trpRS1 基因座是一种广泛分布且自我调节的抗生素抗性盒。本研究为辅助氨酰-tRNA 合成酶基因在细菌中的调控机制提供了新的见解。
