The Streptomyces coelicolor DegS-DegU-like regulon

The Streptomyces coelicolor two genes operon SCO5784-SCO5785 encodes a two-component system which functions in a similar manner to that of the Bacillus subtilis DegS-DegU system. Propagation of the regulatory gene in high copy number results in the overproduction of several extracellular enzymes, among them the major extracellular protease, as well as in a higher level of synthesis of the antibiotic actinorhodin. This two-component system seems to control various processes characterised by the transition from primary to secondary metabolism in S. coelicolor, as determined by proteomic and transcriptomic analices. The presence of the regulatory gene in high copy number in S. coelicolor additionally seems to elicit a stringent response in the bacterial cell. Therefore, we propose renaming S. coelicolor genes SCO5784 and SCO5785 as degS and degU, respectively. All microarray analyses were performed with RNA samples obtained from three independent cultures grown under identical conditions. Hybridisation assays were carried out with cDNA obtained from RNA extracted at the late exponential phase of growth (24h). The transcriptional profile of wild type (S. coelicolor M145) cells carrying the multicopy plasmid pIJ487 was compared with that of the same strain carrying the degU gene cloned in the same plasmid under the control of its own promoter (S. coelicolor M28). And the transcriptional profile of wild type (S, coelicolor M145) cells was compared to that of the DegU deficient strain (S. coelicolor I32).