γ-Butyrolactone autoregulator-receptor system involved in lankacidin and lankamycin production and morphological differentiation in Streptomyces rochei
γ-Butyrolactone autoregulator-receptor system involved in lankacidin and lankamycin production and morphological differentiation in Streptomyces rochei
复制标题
DOI：
10.1099/mic.0.2006/002170-0
复制
发表时间：
2007-06-01
期刊：
影响因子：
2.8
通讯作者：
Kinashi, Haruyasu
中科院分区：
文献类型：
--
作者：
Arakawa, Kenji;Mochizuki, Susumu;Kinashi, Haruyasu
罗氏链霉菌 7434AN4（生产两种聚酮化合物兰卡酸丁和兰卡霉素）的巨型线性质粒 pSLA2-L 上编码了一个 afsA 同源物 (srrX) 和三个 γ-丁内酯受体基因同源物（srrA、srrB 和 srrC）。基因破坏体的构建及其表型研究表明，srrX 和 srrA 在该菌株中形成了 γ-丁内酯受体系统。向 srrX 缺陷突变体中添加 γ-丁内酯部分可恢复兰卡酸丁和兰卡霉素的产生，表明 SrrX 蛋白对于该事件不是必需的。除了对抗生素产生产生积极影响外，srrX 对形态分化也表现出消极影响。受体基因 srrA 逆转了 srrX 的两种作用，而第二个受体基因同源物 srrC 仅在孢子形成中发挥积极作用。此外，第三个同源物 srrB 的破坏大大增加了兰卡酸丁和兰卡霉素的产量。电子显微镜分析表明，srrA 和 srrC 突变体中气生菌丝体的形成停止在不同的阶段。总体而言，这些结果表明 srrX、srrA、srrB 和 srrC 构成了罗氏沙门氏菌抗生素生产和形态分化的复杂调控系统。
An afsA homologue (srrX) and three gamma-butyrolactone receptor gene homologues (srrA, srrB and srrC) are coded on the giant linear plasmid pSLA2-L in Streptomyces rochei 7434AN4, a producer of two polyketide antibiotics, lankacidin and lankamycin. Construction of gene disruptants and their phenotypic study revealed that srrX and srrA make a gamma-butyrolactone receptor system in this strain. Addition of a gamma-butyrolactone fraction to an srrX-deficient mutant restored the production of lankacidin and lankamycin, indicating that the SrrX protein is not necessary for this event. In addition to a positive effect on antibiotic production, srrX showed a negative effect on morphological differentiation. The receptor gene srrA reversed both effects of srrX, while the second receptor gene homologue srrC had only a positive function in spore formation. Furthermore, disruption of the third homologue srrB greatly increased the production of lankacidin and lankamycin. Electron microscopic analysis showed that aerial mycelium formation stopped at a different stage in the srrA and srrC mutants. Overall, these results indicated that srrX, srrA, srrB and srrC constitute a complex regulatory system for antibiotic production and morphological differentiation in S. rochei.