Investigation of the BldB Homologues of Streptomyces Coelicolor: Regulators of Development and Antibiotic Production

Abstract

The Streptomyces are invaluable as a natural source of antibiotics and other bioactive compounds used in medicine and agriculture. S. coelicolor is the model streptomycete, and is studied for its complex secondary metabolism and multicellular life cycle. The subject of this work is bldB, a gene essential for development and antibiotic production in S. coelicolor, and one of its many homologues, located in the abaA antibiotic regulatory locus. The aim was to study the transcriptional regulation of bldB using a luminescent reporter, and investigate the role of each of the genes in the abaA cluster in regulation of antibiotic production, in order to understand the function and mechanism of action of bldB and its homologues. Individual deletion of each of the four genes in the abaA cluster resulted in varying effects on production of the antibiotic CDA. The bldB homologue, SCO0703, was shown to be a positive regulator of CDA, as the null mutant was severely defective in CDA production. It was found that bldB is expressed in most other bld developmental mutants, with the exception of bldD. There was no direct interaction observed between BldD and the bldB promoter, and possible mechanisms of indirect regulation are proposed.