Rational engineering of Streptomyces albus J1074 for the overexpression of secondary metabolite gene clusters

Abstract

BackgroundGenome sequencing revealed that Streptomyces sp. can dedicate up to ~ 10% of their genomes for the biosynthesis of bioactive secondary metabolites. However, the majority of these biosynthetic gene clusters are only weakly expressed or not at all. Indeed, the biosynthesis of natural products is highly regulated through integrating multiple nutritional and environmental signals perceived by pleiotropic and pathway-specific transcriptional regulators. Although pathway-specific refactoring has been a proved, productive approach for the activation of individual gene clusters, the construction of a global super host strain by targeting pleiotropic-specific genes for the expression of multiple diverse gene clusters is an attractive approach.ResultsStreptomyces albus J1074 is a gifted heterologous host. To further improve its secondary metabolite expression capability, we rationally engineered the host by targeting genes affecting NADPH availability, precursor flux, cell growth and biosynthetic gene transcriptional activation. These studies led to the activation of the native paulomycin pathway in engineered S. albus strains and importantly the upregulated expression of the heterologous actinorhodin gene cluster.ConclusionsRational engineering of Streptomyces albus J1074 yielded a series of mutants with improved capabilities for native and heterologous expression of secondary metabolite gene clusters.Electronic supplementary materialThe online version of this article (10.1186/s12934-018-0874-2) contains supplementary material, which is available to authorized users.

Concepts and Methods to Access Novel Antibiotics from Actinomycetes

“…Brady and co-workers could obtain the rare tryptophan dimers hydroxysporine and reductasporine [ 135 ], the cytotoxic anthracycline arimetamycin A [ 136 ], the tetracyclic MRSA-active antibiotic tetarimycin A [ 137 ], the antibiotic cyclic lipopeptides malacidins A and B [ 138 ] and the epoxyketone proteasome inhibitors clarepoxcins A–E and landepoxcins A and B [ 92 ] with the sequence-based metagenomic approach ( Figure 7 ). These natural products were obtained by using Streptomyces albus as heterologous host, underlining this strain as a gifted heterologous host in particular for actinomycete derived BGCs [ 139 ]. Recent developments of utilising different so-called broad host heterologous expression platforms for microbial natural product biosynthetic pathways—in particular various hosts from different phylogenetic background such as myxobacterial microorganisms—was described by Müller et al [ 102 ].…”

Actinomycete-Derived Polyketides as a Source of Antibiotics and Lead Structures for the Development of New Antimicrobial Drugs

“…The downstream evaluation of the collected data sets using bioinformatics tools enables for example the identification of the BGC for the product of interest and/or provides an overview on the overall biosynthetic potential of target strain (genome mining) [9,[358][359][360]. In cases where promising BGCs were identified, however, no products were found with the available fermentation and analytic methods [361][362][363][364], the expression of the clusters and production of the respective metabolite might be achieved by addition of elicitors [341,342,[365][366][367][368][369] or the heterologous expression of the BGC in optimized hosts [370][371][372][373][374][375].…”

Cloning and Overexpression of the Toy Cluster for Titer Improvement of Toyocamycin in Streptomyces diastatochromogenes

“…Because of its fast growth and efficient genetic system, the S. albus J1074 strain is one of the most widely used for the heterologous production of bioactive natural products ( Kallifidas et al, 2018 ; Myronovskyi et al, 2018 ). Therefore, in this study, S. albus J1074 was employed as a host for heterologous expression of the toy cluster.…”