A transposon-based strategy to identify the regulatory gene network responsible for landomycin E biosynthesis.

We report here a transposon-based strategy to generate Streptomyces globisporus 1912 mutants with improved landomycin E production. The modified minitransposon with strong, outward-oriented promoters for the overexpression of downstream-situated genes has been applied for mutant library generation. Approximately 2500 mutants of S. globisporus 1912 were analyzed for landomycin E production, leading to the identification of several overproducers. Subcloning and sequencing of the sites of integration showed that some of the inactivated genes encode proteins with a similarity to known bacterial regulators such as TetR and LuxR families. One of the regulators (GntR type) has shown the strongest influence on the landomycin E production. Its ortholog (encoded by sco3269) in Streptomyces coelicolor was characterized in greater detail and showed similar effects on actinorhodin production and morphological differentiation.