THE BLDB GENE ENCODES A SMALL PROTEIN REQUIRED FOR MORPHOGENESIS, ANTIBIOTIC PRODUCTION, AND CATABOLITE CONTROL IN STREPTOMYCES-COELICOLOR

Mutants blocked at the earliest stage of morphological development in Streptomyces species are called bid mutants. These mutants are pleiotr opically defective in the initiation of development, the ability to pr oduce antibiotics, the ability to regulate carbon utilization, and the ability to send and/or respond to extracellular signals. Here we repo rt the identification and partial characterization of a 99-amino-acid open reading frame (ORF99) that is capable of restoring morphogenesis, antibiotic production, and catabolite control to all of the bldB muta nts. Of the existing bid mutants, bldB is of special interest because the phenotype of this mutant is the most pleiotropic. DNA sequence ana lysis of ORF99 from each of the existing bldB mutants identified base changes either within the coding region of the predicted protein or in the regulatory region of the gene. Primer extension analysis identifi ed an apparent transcription start site. a promoter fusion to the xylE reporter gene showed that expression of bldB is apparently temporally regulated and that the bins gene product is involved in the regulatio n of its own expression.