Function of Streptomyces antibiotic regulatory proteins family transcriptional regulator ctcB in the biosynthetic cluster of chlortetracycline

Abstract:

[Objective] In order to understand the regulatory mechanisms of chlortetracycline biosynthesis in an industrial strain, function of an Streptomyces antibiotic regulatory proteins (SARP) family transcriptional regulator ctcB in the biosynthetic gene cluster of chlortetracycline was studied.[Methods] By double crossover recombination, we constructed Streptomyces aureofaciens F3 with disrupted SARP family transcriptional regulator ctcB gene. The amplicons of RT-PCR were designed to cover the adjacent genes for verification of the operons in chlortetracycline biosynthetic cluster. Transcriptional level was analyzed in the chlortetracycline biosynthetic gene cluster in the wild type strain and the ctcB gene disrupted mutant LJIA02 by quantitative real-time RT-PCR.[Results] The disruption mutant LJIA02 abolished tetracycline and chlortetracycline production. In RT-PCR six operons were confirmed in chlortetracycline biosynthetic cluster. Quantitative real-time RT-PCR indicated that ctcB directly activated five promoters from ctcG-D, ctcH-K, ctcN-P, ctcW-T and ctcQ.[Conclusion] CtcB is an essential activator as an SARP family transcriptional regulator in the chlortetracycline biosynthetic gene cluster.