earticle

영어

In previous study, we successfully utilized Streptomyces interspecies DNA microarray analysis system to identify novel regulatory genes associated with secondary metabolite overproduction in S. peucetius Doxorubicin (DXR) overproducing industrial strain [1]. Especially wblA, a whiB-like putative transcription factor gene, and SCO1712, a tetR-family transcriptional regulatory gene, were identified as strong antibiotic biosynthetic down-regulators in both S. coelicolor as well as S. peucetius species. Moreover, these two strong antibiotic down-regulators were specifically deleted in the S. coelicolor wild-type chromosome, resulting S. coelicolor △wblA△SCO1712 double knock-out (KO) mutant which shown significantly higher actinorhodin (Act) productions [2]. To further increase our understanding about the genetic nature of Streptomyces antibiotic overproduction, a comparative transcriptome analysis was conducted again using S. coelicolor whole genome chip between S. coelicolor wild-type and a S. coelicolor △wblA△SCO1712 double KO mutant. As a result, the double KO strain was found to express the Act biosynthetic cluster genes stronger than the wild-type. Also, various gene expression signatures were obtained by deletion of wblA and SCO1712. 875 genes showed a two-fold or greater change in expression at two or more time points and 14 genes showed non-change in expression pattern at most of time points. First, in case of putative wblA &SCO1712 dependent genes, expression pattern was confirmed in wild-type and double KO mutant using RT-PCR. And these genes were individually over-expression into S. coelicolor to verity the biological functions of these putative targets, so we selected some putative effective antibiotics-relating regulators in M145 wild-type. Second, SCO5426 relating regulation of carbon flux was found among wblA & SCO1712 independent genes [3]. So SCO5426 was disrupted in S. coelicolor △wblA△SCO1712 double KO mutant additionally and Act productivity was increased than double KO mutant. This additional transcriptomics-driven approach in a double KO mutant led to the identification of previously-unidentified novel wblA &SCO1712 dependent or independent regulatory genes related to secondary metabolite overproduction.