CHARACTERIZATION OF SPAA, A STREPTOMYCES-COELICOLOR GENE HOMOLOGOUS TO A GENE INVOLVED IN SENSING STARVATION IN ESCHERICHIA-COLI

A Streptomyces coelicolor gene, called spaA, homologous to the station ary phase regulatory gene rspA of Escherichia coli [Huisman and Kelter (1994) Science 265, 537-539], was cloned using the Streptomyces ambof aciens rspA homologue spa2 [Schneider et al. (1993) J. Gen. Microbiol. 139, 2559-2567] as a probe. Considerable differences in sequence and in genetic context were detected between spa2 of S. ambofaciens and sp aA of S. coelicolor. A cloned internal fragment of spaA was used to di rect integration of a phage vector into the spaA gene. The disruption caused delayed antibiotic production (undecylprodigiosin and actinorho din) and led on further incubation to increased actinorhodin productio n at high, but not low, cell density. This phenotype was apparent only on the nutritionally poorest of three media tested. The attempted use of an integrating plasmid-based system for gene replacement of spaA g ave rise to extensive deletions of adjacent chromosomal DNA.