Activation and identification of five clusters for secondary metabolites in Streptomyces albus J1074

Abstract

Streptomyces albus J1074 is a streptomycete strain widely used as a host for expression of secondary metabolite gene clusters. Bioinformatic analysis of the genome of this organism predicts the presence of 27 gene clusters for secondary metabolites. We have used three different strategies for the activation of some of these silent/cryptic gene clusters in S. albus J1074: two hybrid polyketide-non-ribosomal peptides (PK-NRP) (antimycin and 6-epi-alteramides), a type I PK (candicidin), a non-ribosomal peptides (NRP) (indigoidine) and glycosylated compounds (paulomycins). By insertion of a strong and constitutive promoter in front of selected genes of two clusters, production of the blue pigment indigoidine and of two novel members of the polycyclic tetramate macrolactam family (6-epi-alteramides A and B) was activated. Overexpression of positive regulatory genes from the same organism also activated the biosynthesis of 6-epi-alteramides and heterologous expression of the regulatory gene pimM of the pimaricin cluster activated the simultaneous production of candicidins and antimycins, suggesting some kind of cross-regulation between both clusters. A cluster for glycosylated compounds (paulomycins) was also identified by comparison of the high-performance liquid chromatography profiles of the wild-type strain with that of a mutant in which two key enzymes of the cluster were simultaneously deleted.

Toward Systems Metabolic Engineering of Streptomycetes for Secondary Metabolites Production

“…Furthermore, the compound isolated from S. viridochromogenes was found to be a novel pigmented PK produced from an otherwise silent BGC of the type II PKS. Although this activation strategy bears striking similarity to a technique previously reported for the activation of five gene clusters in S. albus J1074, [52] the incentive to use the CRISPR-Cas9 system is the increased efficiency of HRs, presenting an improved method for genetic manipulation of strains suffering from the low efficiency of natural recombination.…”

Electrical Retrieval of Living Streptomycete Spores Using a Potential-Controlled ITO Electrode

“…The production of a variety of antibiotics is regulated by different regulatory mechanisms in streptomycetes 13,14,[17][18][19] and it is essential to choose a wide range of media for their production. 15 Because the electrically attached Streptomyces sp.…”

“…Genetically modified streptomycetes have unleashed the production of many new biologically active compounds. 13,14,[17][18][19] Nevertheless, the rate of novel compound discovery from terrestrial microorganisms has recently decreased significantly. 20 Over the past three decades, marine environments have continued to supply a number of novel actinomycetes and bioactive compounds.…”

Polyene macrolide biosynthesis in streptomycetes and related bacteria: recent advances from genome sequencing and experimental studies

“…Microbial genome sequencing is also contributing to discovery of new polyenes and to a more complete understanding of their biosynthesis. Candicidin is frequently re-isolated and its biosynthetic gene cluster appears in several genomes (Jorgensen et al, 2009;Seipke et al, 2011b;Olano et al, 2014;Tang et al, 2015;Komaki et al, 2015;Liu et al, 2015a). Since the sequencing of the nystatin biosynthetic genes in S. noursei (Brautaset et al, 2000), at least three other closely related clusters have been found (Kim et al, 2009;Barke et al, 2012;Cui et al, 2015).…”