9316912 Westpheling Streptomyces are Gram-positive soil bacteria that are of special interest because of their remarkably complex morphological development and because they produce as secondary metabolites most of the antibiotics used in human and animal health care. Although little is understood about the molecular physiology of these bacteria, it is apparent that the regulation of carbon utilization is of central importance in the gene expression pathways for both morphological development and antibiotic biosynthesis. To gain an understanding of the mechanism of catabolite control in Streptomyces we are studying the regulation of a family of genes involved in the utilization of chitin, a complex carbohydrate and a major source of carbon in the soil. The synthesis of chitinase enzymes is tightly repressed by glucose and strongly induced by chitin. In preliminary work we have established that regulation for at least one of the chitin. In preliminary work we have established that regulation for at least one of the chitinase genes, chi63, occurs at the level of transcription initiation. We have been a systematic analysis of mutations within the promoter region of chi63 and used a transcriptional fusion to the xy1E reporter gene, to identify chromosomal mutations that define the pathway for glucose repression and chitin induction of chitinase synthesis. We are defining the elements of the chitinase promoters that determine regulation and promoter activity; beginning a study to identify and characterize genes that act to facilitate the global regulation of catabolite repression in Streptomyces. %%% We hope as a result of this work to contribute to the understanding of gene regulation in an important class of bacteria where relatively little is known about the way in which gene expression is controlled. ***
