Gamma-Butyrolactone Regulatory System of Streptomyces chattanoogensis Links Nutrient Utilization, Metabolism, and Development
Gamma-Butyrolactone Regulatory System of Streptomyces chattanoogensis Links Nutrient Utilization, Metabolism, and Development
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Chattanoogensis链霉菌的γ-丁内酯调节系统将养分利用、代谢和发育联系起来
DOI：
10.1128/aem.05898-11
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发表时间：
2011-12-01
影响因子：
4.4
通讯作者：
Li, Yong-Quan
中科院分区：
文献类型：
--
作者：
Du, Yi-Ling;Shen, Xue-Ling;Li, Yong-Quan
摘要由几种链霉菌产生的γ-丁内酯(GBL)已被证明是激活抗生素生产的群体感应信号分子。产查塔诺链霉菌L10的GBL系统由三个基因组成：scgA、scgX和scgR。ScgA和scgX都参与GBL的产生，而scgR编码GBL受体。查塔诺产链霉菌的Δ、scgA和ΔscgX突变体表现出相同的行为：它们在深层培养中存在生长缺陷，在固体培养上延迟或取消了形态分化和次生代谢产物的产生。ScgR可与SCGA启动子区域结合并抑制其转录。此外，SCGA似乎还受GBL介导的负反馈系统的控制。因此，很明显，GBL的生物合成受到严格控制，以确保代谢转换的正确时机。通过基因组SELEX和转录分析鉴定了另一个直接的ScgR靶基因gbdA。对L10及其突变体ΔscgA的蛋白质组学比较分析表明，gbl系统影响50多个蛋白质的表达，包括参与碳吸收系统、初级代谢和胁迫反应的酶，因此我们认为scgR-scgA-scgX构成了一个新的gbl调节系统，参与营养利用，触发适应性反应，最终决定从初级代谢到次生代谢的转换。
ABSTRACT Gamma-butyrolactones (GBLs) produced by several Streptomyces species have been shown to serve as quorum-sensing signaling molecules for activating antibiotic production. The GBL system of Streptomyces chattanoogensis L10, a producer of antifungal agent natamycin, consists of three genes: scgA, scgX, and scgR. Both scgA and scgX contribute to GBL production, while scgR encodes a GBL receptor. ΔscgA and ΔscgX mutants of S. chattanoogensis behaved identically: they had a growth defect in submerged cultures and delayed or abolished the morphological differentiation and secondary metabolites production on solid medium. ScgR could bind to the promoter region of scgA and repress its transcription. Moreover, scgA seems also to be controlled by a GBL-mediated negative-feedback system. Hence, it is apparent that GBL biosynthesis is tightly controlled to ensure the correct timing for metabolic switch. An additional direct ScgR-target gene gbdA was identified by genomic SELEX and transcriptional analysis. Comparative proteomic analysis between L10 and its ΔscgA mutant revealed that the GBL system affects the expression of more than 50 proteins, including enzymes involved in carbon uptake system, primary metabolism, and stress response, we thus conclude that scgR-scgA-scgX constitute a novel GBL regulatory system involved in nutrient utilization, triggering adaptive responses, and finally dictating the switch from primary to secondary metabolism.