Streptomyces are soil bacteria that undergo morphogenesis in response to environmental stress. These microorganisms also produce the majority of antibiotics and antimetabolites used therapeutically throughout the world. The genus Streptomyces is therefore of interest from both biological and practical viewpoints. To understand the nature of regulatory mechanisms that function during cellular differentiation, we will characterize a cloned DNA fragment (ORF1425) that is involved in the sporulation of Streptomyces griseus. The expression of ORF1425 will be analyzed by RNA hybridization studies, to determine whether the ORF1425 transcript accumulates at a specific stage of the life cycle and whether there is more than one transcript made from the ORF1425 gene. We will initiate studies to determine whether sporulation of S. griseus is, like that of S. coelicolor, dependent on the bldA gene product by cloning and sequencing the bldA gene product by cloning and sequencing the bldA gene from S. griseus and the ORF1425 gene from S. coelicolor. Analysis of the regulation of ORF1425 expression during the streptomycete life cycle will contribute significantly to our knowledge of mechanisms by which these relatively simple organisms regulate developmental processes in a temporal fashion. Because streptomycetes tend to undergo sporulation and antibiotic production simultaneously, the results of these experiments may also elucidate mechanisms by which streptomycetes regulate the biosynthesis of antibiotics. The use of Streptomyces as a model system will extend our understanding of fundamental patterns of cell differentiation that operate in both simple and complex organisms.
