Characterization and analysis of the regulatory network involved in control of lipomycin biosynthesis in Streptomyces aureofaciens Tu117

Analysis of the alpha-lipomycin biosynthesis gene cluster of Streptomyces aureofaciens Tu117 led to the identification of five putative regulatory genes, which are congregated into a subcluster. Analysis of the lipReg1-4 and lipX1 showed that they encode components of two-component signal transduction systems (LipReg1 and LipReg2), multiple antibiotics resistance-type regulator (LipReg3), large ATP-binding regulators of the LuxR family-type regulator (LipReg4), and small ribonuclease (LipRegX1), respectively. A combination of targeted gene disruptions, complementation experiments, lipomycin production studies, and gene expression analysis via RT-PCR suggests that all regulatory lip genes are involved in alpha-lipomycin production. On the basis of the obtained data, we propose that LipReg2 controls the activity of LipReg1, which in its turn govern the expression of the alpha-lipomycin pathway-specific regulatory gene lipReg4. The ribonuclease gene lipX1 and the transporter regulator lipReg3 appear to work independently of genes lipReg1, lipReg2, and lipReg4.