A Regulator Based "Semi-Targeted" Approach to Activate Silent Biosynthetic Gene Clusters

Area of Science:

• Microbiology
• Synthetic Biology
• Natural Product Discovery

Background:

• Many microbial biosynthetic gene clusters (BGCs) remain silent under standard laboratory conditions, limiting the discovery of novel natural products.
• Activating these silent BGCs is crucial for exploring the full biosynthetic potential of microorganisms.

Purpose of the Study:

• To develop and apply a novel "semi-targeted" approach for activating silent BGCs in Streptomyces.
• To identify specific regulatory genes responsible for activating BGCs and inducing the production of secondary metabolites.

Main Methods:

• Construction of integrative plasmids carrying cluster situated regulators (CSRs) and Streptomyces antibiotic regulatory proteins (SARPs) under the ermE*p promoter.
• Introduction of these plasmids into Streptomyces sp. strains TÜ17, TÜ10, and TÜ102.
• Analysis of BGC activation and metabolite production in engineered strains.

Main Results:

• Activation of mayamycin A production in S. sp. TÜ17 via CSRs, with Aur1P identified as the key activator.
• Production of a chartreusin-like compound in S. sp. TÜ102 upon SARP-plasmid introduction.
• Warkmycin-BGC activation in S. sp. TÜ10 using CSRs, requiring co-expression of specific regulators (aur1PR3 and griR).

Conclusions:

• The "semi-targeted" approach effectively activates silent BGCs in Streptomyces, enabling the discovery of new compounds.
• Specific combinations of regulatory genes are essential for successful BGC activation in different strains.
• This strategy holds promise for uncovering novel bioactive molecules from microbial dark matter.