Key Laboratory of Tropical Marine Bio-Resources and Ecology, Guangdong Provincial Key Laboratory of Applied Marine Biology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China.
Key Laboratory of South China Sea Fishery Resources Exploitation and Utilization, Ministry of Agriculture and Rural Affairs, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou, China.
Appl Environ Microbiol. 2019 Sep 17;85(19). doi: 10.1128/AEM.00880-19. Print 2019 Oct 1.
Bacteria synthesize amino acids according to their availability in the environment or, in the case of pathogens, within the host. We explored the regulation of the biosynthesis of branched-chain amino acids (BCAAs) (l-leucine, l-valine, and l-isoleucine) in , a marine fish and shellfish pathogen and an emerging opportunistic human pathogen. In this species, the operon encodes the main pathway for biosynthesis of BCAAs. Its upstream regulatory region shows no sequence similarity to the corresponding region in or other , and yet we show that this operon is regulated by transcription attenuation. The translation of a BCAA-rich peptide encoded upstream of the structural genes provides an adaptive response similar to the canonical model. This study of a nonmodel Gram-negative organism highlights the mechanistic conservation of transcription attenuation despite the absence of primary sequence conservation. This study analyzes the regulation of the biosynthesis of branched-chain amino acids (leucine, valine, and isoleucine) in , a marine bacterium that is pathogenic to fish and humans. The results highlight the conservation of the main regulatory mechanism with that of the enterobacterium , suggesting that such a mechanism appeared early during the evolution of Gram-negative bacteria, allowing adaptation to a wide range of environments.
细菌根据环境中（或病原体在宿主内）的可用性来合成氨基酸。我们研究了海洋鱼类和贝类病原体和新兴机会性病原体中的支链氨基酸（BCAA）（亮氨酸、缬氨酸和异亮氨酸）生物合成的调节。在该物种中， 操纵子编码了 BCAA 生物合成的主要途径。其上游调控区与 或其他 中的相应区域没有序列相似性，但我们表明该操纵子受转录衰减调节。结构基因上游编码的富含 BCAA 的肽的翻译提供了类似于 经典模型的适应性反应。这项对非模式革兰氏阴性生物的研究强调了尽管没有主要序列保守性，但转录衰减的机制保守性。本研究分析了海洋细菌 中支链氨基酸（亮氨酸、缬氨酸和异亮氨酸）生物合成的调节。结果突出了与肠杆菌的主要调节机制的保守性，表明这种机制在革兰氏阴性菌的进化早期就出现了，允许其适应广泛的环境。
