Institute of Pharmaceutical Biotechnology, Zhejiang University, Hangzhou, 310058, China.
Zhejiang Provincial Key Laboratory for Microbial Biochemistry and Metabolic Engineering, Hangzhou, 310058, China.
J Ind Microbiol Biotechnol. 2019 May;46(5):725-737. doi: 10.1007/s10295-018-02127-5. Epub 2019 Feb 2.
Antibiotic production during secondary metabolism in Streptomyces spp. is elaborately controlled by multiple environmental signals and intracellular cascades. These include the two-component system PhoRP responding to phosphate starvation and a conserved signaling pathway mediated by the pleiotropic regulator AdpA. However, little information exists about how these two pathways work together for secondary metabolite production of Streptomyces. Herein, we report the dual regulation from the phosphate starvation-responsive regulator PhoP and AdpA on atrA promoter (atrAp) for the production of daptomycin, an antibiotic produced by Streptomyces roseosporus. We found that PhoP directly binds to atrAp, positively regulates atrA expression and thus daptomycin production. We also observed positive auto-regulation of phoRP expression during fermentation for daptomycin production. Moreover, partial overlap between PhoP- and AdpA-binding sites on atrAp was observed, which results in partial competitive binding between these two regulators. This partial overlapping and competition between PhoP and AdpA was further confirmed by mutations and binding assays. In summary, our findings have revealed dual regulation of PhoP and AdpA on the same promoter for antibiotic production in Streptomyces. This mechanism would be beneficial to further environment-responsive fermentation optimization for antibiotic production.
次级代谢中链霉菌属抗生素的产生受到多种环境信号和细胞内级联的精细调控。这些信号包括对磷酸盐饥饿做出反应的双组分系统 PhoRP 和由多效调节因子 AdpA 介导的保守信号通路。然而，关于这两种途径如何协同作用以促进链霉菌产生次级代谢物的信息却很少。本文报道了磷酸盐饥饿响应调节因子 PhoP 和 AdpA 对 daptomycin 产生的调节作用，daptomycin 是由玫瑰孢链霉菌产生的一种抗生素。我们发现 PhoP 可直接与 atrAp 结合，正向调节 atrA 的表达，从而促进 daptomycin 的产生。我们还观察到在发酵过程中，daptomycin 产生时 phoRP 的表达存在正反馈调节。此外，在 atrAp 上观察到 PhoP 和 AdpA 结合位点的部分重叠，导致这两个调节因子之间存在部分竞争性结合。通过突变和结合实验进一步证实了 PhoP 和 AdpA 之间的这种部分重叠和竞争。综上所述，本研究揭示了 PhoP 和 AdpA 对链霉菌中同一启动子上抗生素产生的双重调控。该机制有助于进一步优化抗生素生产的环境响应发酵。
