A MarR-family transcriptional factor MapR positively regulates actinorhodin production in Streptomyces coelicolor

Production of secondary metabolites is tightly regulated by transcriptional regulators in Streptomyces. Many regulators have been identified by gene disruption in Streptomyces; however, there are still unknown regulatory genes yet to be revealed due to gene silence under laboratory culture conditions. In present study, a T7 expression system was used to identify novel regulators by gene deletion and constitutive-expression of nine candidates. We reported that the constitutive-expression of a MarR family transcriptional regulator MapR (SCO2398) resulted in increase of actinorhodin (ACT) production. The expression profiling indicated that MapR regulates ACT production through a transcriptional cascade. Collectively, our study suggests that MapR serves as a novel positive regulator of ACT production.