A DEVELOPMENTALLY-REGULATED GENE ENCODING A REPRESSOR-LIKE PROTEIN ISESSENTIAL FOR SPORULATION IN STREPTOMYCES-COELICOLOR A3(2)

whiH is one of several known loci specifically needed for the orderly multiple sporulation septation of aerial hyphae of Streptomyces coelic olor A3(2) and for the expression of at least some late sporulation ge nes. DNA complementing whiH mutants was located immediately upstream o f hrdB, which encodes the principal a factor of S. coelicolor. Sequenc ing revealed a gene whose disruption gave rise to a typical whiH mutan t phenotype. Four whiHmutants contained base changes or a frameshift i n this gene. The deduced product of whiH is related to a large family of bacterial regulatory proteins, the most similar being several repre ssors (such as GntR of Bacillus subtilis) responsive to carboxylate-co ntaining intermediates in carbon metabolism. Transcription of whiH was initiated at a single promoter, P-whiH Levels of whiH mRNA were devel opmentally regulated, increasing sharply when aerial mycelium was pres ent, and reaching a maximum approximately when spores were first detec table. Transcript levels were markedly increased in a whiH mutant, ind icating the possible involvement of WhiH in negative regulation of its own production. P-wh/H was directly dependent on the a factor encoded by another sporulation gene, whiG, as shown by in vivo and in vitro t ranscription analysis.