We previously reported that the two-component system MacRS regulates morphogenesis and production of the blue-pigmented antibiotic actinorhodin (ACT) in Streptomyces coelicolor. In this study, the role of MacRS was further extended to include control of the production of the red-pigmented antibiotic undecylprodigiosin (RED) and the calcium-dependent antibiotic (CDA), and control of other important cellular activities. Our data indicated that disruption of the MacRS TCS reduced production not only of ACT but also of RED and CDA. RNA-Seq analysis revealed that genes involved in both secondary metabolism and primary metabolism are differentially expressed in the MacRS deletion mutant ΔmacRS. Moreover, we found that genes of the Zur regulon are also markedly downregulated in ΔmacRS, suggesting a role for macRS in zinc homeostasis. In addition to previously identified MacR sites with strong matches to the MacR consensus recognition sequence, a genome-wide search revealed over one hundred less-stringent matches, including potential sites upstream of absR1, crgA, and smeA. Electrophoretic mobility shift assays demonstrated that MacR binds some of these sites in vitro. Although there is no strong MacR site upstream of the ACT regulatory gene actII-orf4 (sco5085), we showed that an engineered MacR site enhanced ACT production, providing an approach for modulating production of useful compounds. Altogether, our work suggests an important role for MacRS in a range of cellular activities in Streptomyces and its potential application in strain engineering.

我们之前报道过双组分系统 MacRS 调节天蓝色链霉菌中蓝色色素抗生素放线菌素 (ACT) 的形态发生和产生。在这项研究中，MacRS 的作用进一步扩展到包括控制红色抗生素十一烷基灵菌红素 (RED) 和钙依赖性抗生素 (CDA) 的产生，以及控制其他重要的细胞活动。我们的数据表明，MacRS TCS 的中断不仅会降低 ACT 的产量，还会降低 RED 和 CDA 的产量。RNA-Seq 分析显示，参与次级代谢和初级代谢的基因在 MacRS 缺失突变体 Δ macRS中差异表达。此外，我们发现 Zur 调节子的基因在 Δ 中也显着下调macRS，表明macRS在锌稳态中的作用。除了先前确定的与 MacR 共识识别序列强匹配的 MacR 位点外，全基因组搜索揭示了一百多个不太严格的匹配，包括absR1、crgA和smeA上游的潜在位点。电泳迁移率变化分析表明 MacR 在体外结合了这些位点中的一些。虽然ACT调控基因actII-orf4（sco5085）上游没有强MacR位点)，我们表明工程化的 MacR 位点增强了 ACT 的产生，提供了一种调节有用化合物产生的方法。总而言之，我们的工作表明 MacRS 在链霉菌属的一系列细胞活动中的重要作用及其在菌株工程中的潜在应用。