Som Nicolle F, Heine Daniel, Holmes Neil A, Munnoch John T, Chandra Govind, Seipke Ryan F, Hoskisson Paul A, Wilkinson Barrie, Hutchings Matthew I
School of Biological Sciences, University of East AngliaNorwich, United Kingdom.
Department of Molecular Microbiology, John Innes CentreNorwich, United Kingdom.
Front Microbiol. 2017 Jun 28;8:1145. doi: 10.3389/fmicb.2017.01145. eCollection 2017.
bacteria make numerous secondary metabolites, including half of all known antibiotics. Production of antibiotics is usually coordinated with the onset of sporulation but the cross regulation of these processes is not fully understood. This is important because most antibiotics are produced at low levels or not at all under laboratory conditions and this makes large scale production of these compounds very challenging. Here, we characterize the highly conserved actinobacterial two-component system MtrAB in the model organism and provide evidence that it coordinates production of the antibiotic chloramphenicol with sporulation. MtrAB are known to coordinate DNA replication and cell division in where TB-MtrA is essential for viability but MtrB is dispensable. We deleted in and this resulted in a global shift in the metabolome, including constitutive, higher-level production of chloramphenicol. We found that chloramphenicol is detectable in the wild-type strain, but only at very low levels and only after it has sporulated. ChIP-seq showed that MtrA binds upstream of DNA replication and cell division genes and genes required for chloramphenicol production. , , , and () are DNA binding targets for MtrA in both and . Intriguingly, over-expression of TB-MtrA and gain of function TB- and Sv-MtrA proteins in also switched on higher-level production of chloramphenicol. Given the conservation of MtrAB, these constructs might be useful tools for manipulating antibiotic production in other filamentous actinomycetes.
细菌能产生大量次级代谢产物，其中包括所有已知抗生素的一半。抗生素的产生通常与孢子形成的开始相协调，但这些过程的交叉调控尚未完全了解。这一点很重要，因为大多数抗生素在实验室条件下产量很低或根本不产生，这使得大规模生产这些化合物极具挑战性。在这里，我们在模式生物中对高度保守的放线菌双组分系统MtrAB进行了表征，并提供证据表明它能协调抗生素氯霉素的产生与孢子形成。已知MtrAB在协调DNA复制和细胞分裂，其中结核分枝杆菌的MtrA对生存能力至关重要，但MtrB是可有可无的。我们在结核分枝杆菌中删除了它，这导致了代谢组的整体变化，包括组成型的、更高水平的氯霉素产生。我们发现野生型菌株中可检测到氯霉素，但仅在极低水平且仅在其形成孢子后。染色质免疫沉淀测序显示MtrA结合在DNA复制、细胞分裂基因以及氯霉素产生所需基因的上游。在结核分枝杆菌和天蓝色链霉菌中，pimA、whiB6、whiB7和sigF（rshA）是MtrA的DNA结合靶点。有趣的是，在天蓝色链霉菌中过表达结核分枝杆菌的MtrA以及功能获得型的结核分枝杆菌和天蓝色链霉菌的MtrA蛋白也开启了更高水平的氯霉素产生。鉴于MtrAB的保守性，这些构建体可能是用于操纵其他丝状放线菌抗生素产生的有用工具。
