title: Molecular and cytological analysis of the expression of Streptomyces sporulation regulatory gene whiH.
abstract: The whiH gene is required for the orderly sporulation septation that divides aerial hyphae into spores in Streptomyces coelicolor. Here, we use a whiHp-mCherry transcriptional reporter construct to show that whiHp is active specifically in aerial hyphae, fluorescence being dependent on sporulation sigma factor WhiG. The results show that the promoter is active before the septation event that separates the subapical compartment from the tip compartment destined to become a spore chain. We conclude that WhiG-directed RNA polymerase activity, which is required for whiH transcription, must precede this septation event and is not restricted to apical sporogenic compartment of the aerial hyphae. Further, it is demonstrated that WhiH, a predicted member of the GntR family of transcription factors, is able to bind specifically to a sequence in its own promoter, strongly suggesting that it acts as an autoregulatory transcription factor. Finally, we show by site-directed mutagenesis and a genetic complementation test that whiH is translated from a start codon overlapping with the previously identified transcription start point, implying leaderless transcription.
authors: Department of Biology, Lund University, Lund, Sweden.
authors: Jessica
authors: J
authors: Persson
authors: Keith F
authors: KF
authors: Chater
authors: Klas
authors: K
authors: Flärdh
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D018507:Gene Expression Regulation, Developmental; D025301:Hyphae / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D012808:Sigma Factor / Q000235:genetics / Q000378:metabolism; D013171:Spores, Bacterial / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism; D048372:Streptomyces coelicolor / Q000166:cytology / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D012097:Repressor Proteins; D012808:Sigma Factor; C115233:whiH protein, Streptomyces; C061314:whiG protein, Streptomyces coelicolor