Cross-genome comparative transcriptome analyses were previously conducted using the sequenced Streptomyces coelicolor genome microarrays to understand genetic nature of doxorubicin (DXR)overproduction in the S.peucetius industrial mutant (OIM),identifying a whiB-like putative transcription factor (wblA-sco) as a global antibiotic down-regulator in S.coelicolor [1].In this study.a total genomic DNA library of a DXR-overpreducing S.peucetius IM was constructed and screened using a wblA-sco as a probe,resulting in isolation of a wblA ortholog (wblA-spe) showing 95% amino acid identity to wblA-sco.