원문정보
초록
영어
Genomics-guided technologies including cDNA microarrays have been successfully applied for the identification of gene expression alterations in various Streptomyces strains. To detect global changes in mRNA abundance associated with overproduction of anti-cancer doxorubicin, reverse engineering strategy via comparative transcriptome analyses in cultures of the wild-type and industrial mutant strains of S. peucetius were conducted using interspecies S. coelicolor cDNA microarrays. Among 160 S. coelicolor potential candidate genes showing at least a two-fold change in transcription profile, a SCO3579 (whiB-like gene named wblA) inhibited the biosynthesis of doxorubicin in S. peucetius as well as the production of antibiotics in S. coelicolor, suggesting that wblA and its homologs act globally among streptomycetes as down-regulators of antibiotic biosynthesis. In addition, one of tetR-family transcriptional regulatory genes was also identified to encode a global antibiotic regulator. Gene disruption of S. coelicolor
revealed that this tetR-family regulatory gene down-regulates antibiotic biosynthesis through pathway-specific regulators even in the presence of the wblA transcript, implying that it might encode a wblA-bypassing antibiotic down-regulator. To isolate and manipulate a wblA homolog in a doxorubicin-overproducing S. peucetius industrial stain, a total genomic DNA library from a S. peucetius industrial mutant was constructed and screened using a S. coelicolor wblA as a probe, resulting in isolation of a wblA ortholog (wblA-spe) showing 95% amino acid identity to a S. coelicolor wblA. Gene disruption of wblA-spe from the S. peucetius industrial mutant resulted in additional increase of doxorubicin production, implying that doxorubicin productivity in
the S. peucetius industrial mutant strain could be further improved via rational comparative transcriptomics-guided target gene manipulation.