Project description:The aim of this experiment was to map the transcription start sites (TSSs) in the bottromycin biosynthetic gene cluster from Streptomyces scabies, qualitatively assess the expression levels of this cluster within the bacterium's transcriptome and evaluate whether deletion of a potential regulatory gene in the cluster, btmL affects gene cluster expression.
Project description:ForJ, ForF and ForZ are cluster situated regulators of the formicamycin biosynthetic gene cluster in Streptomyces forimcae. This ChIP Sequencing experiment was conducted to identify where in the genome these regulators bind in order to identify which transcripts they might regulate.
Project description:<p>Natural products from microorganisms are important sources for drug discovery. With the development of high-throughput sequencing technology and bioinformatics, a large amount of uncharacterized biosynthetic gene clusters (BGCs) in microorganisms have been found, which show the potential for novel natural product production. 9 BGCs containing PKS and/or NRPS in <em>Streptomyces globisporus</em> C-1027 were transcriptionally low/silent under the experimental fermentation conditions, and the products of these clusters are unknown. Thus, we tried to activate these BGCs to explore cryptic products of this strain. We constructed the cluster-situated regulator overexpressing strains which contained regulator gene(s) under the control of the constitutive promoter <em>ermE</em>*p in <em>S. globisporus</em> C-1027. Overexpression of regulators in cluster 26 resulted in significant transcriptional upregulation of biosynthetic genes. With the separation and identification of products from the overexpressing strain OELuxR1R2, 3 <em>ortho</em>-methyl phenyl alkenoic acids (compounds <strong>1-3</strong>) were obtained. Gene disruption showed that compounds <strong>1</strong> and <strong>2</strong> were completely abolished in the mutant GlaEKO, but were hardly affected by deletion of the genes <em>orf3</em> or <em>echA</em> in cluster 26. The type II PKS biosynthetic pathway of chain-extended cinnamoyl compounds was deduced by bioinformatics analysis. This study showed that overexpression of the 2 adjacent cluster-situated LuxR regulator(s) is an effective strategy to connect the orphan BGC to its products.</p>
Project description:Streptomyces sp. are a rich source for natural products with recognized industrial value, explaining the high interest to improve and streamline production in these microbes. Here, we studied the production of pamamycins, macrodiolide homologues with a high activity against multi-resistant pathogenic microbes, using recombinant S. albus J1074/R2. Talc particles of micrometer size added to submerged cultures of the recombinant strain tripled pamamycin production up to 50 mg L-1. Furthermore, they strongly affected morphology, reduced the size of cell pellets, formed by the filamentous microbe during the process, up to six-fold, and shifted the pamamycin spectrum to larger derivatives. Integrated analysis of transcriptome and metabolome of particle-enhanced and control cultures provided detailed insights into the underlying molecular changes. The microparticles affected the expression of 3341 genes (56%), revealing a global and fundamental impact on metabolism. Morphology-associated genes, encoding major regulators such as SsgA, RelA, EshA, Factor C, as well as chaplins and rodlins, were found massively upregulated, indicating that the particles caused a substantially accelerated morphogenesis. In line, the pamamycin cluster was strongly upregulated (up to log2 10-fold). Furthermore, the microparticles perturbed genes encoding for central catabolism and CoA-ester metabolism, which were mainly activated. The altered expression resulted in changes in the availability of intracellular CoA-esters, the building blocks of pamamycin. Notably, the ratio between methylmalonyl CoA and malonyl-CoA was increased four-fold. Both metabolites compete for incorporation into pamamycin so that the altered availability explained the pronounced preference for larger derivatives in the microparticle-enhanced process. Our findings are straightforward to further develop pamamycins into antituberculosis leads. The novel insights into the behavior of S. albus in response to talc appears of general relevance to further explore and upgrade the concept of microparticle enhanced cultivation, widely used for filamentous microbes.