A response regulator-like protein that functions at an intermediate stage of sporulation in Streptomyces coelicolor A3(2)

whil is one-of several loci originally described as essential for sporulati on in Streptomyces coelicolor A3(2). We have characterized whil at the mole cular level. It encodes an atypical member of the response regulator family of proteins, lacking at least two of the-residues strongly conserved in th e conventional phosphorylation pocket. It is not adjacent to a potential se nsor kinase gene. Fifteen mutant alleles of whil were sequenced, revealing, among others, six mutations affecting conserved amino acids, several frame shift mutations and one mutation in the promoter. The whil promoter is spec ifically transcribed by the sporulation-specific sigma(WhiG)-containing for m of RNA polymerase.;Transcription of whil is temporally controlled;: reach ing a maximum level coincident with the formation of spores. Further transc riptional studies: suggested that Whil is involved directly or indirectly:i n repressing its own expression and that of :another: sigma(WhiG)-dependent sporulation-specific regulatory gene, whiH.