title: Cross-interaction of anti-σH factor RshA with BldG, an anti-sigma factor antagonist in Streptomyces griseus.
abstract: Stress-response sigma factor σ(H) is negatively regulated by its cognate anti-sigma factor RshA in Streptomyces griseus. As the overexpression of RshA in the wild-type strain confers a distinctive bald phenotype (deficiency in aerial mycelium formation and streptomycin production), RshA is supposed to associate with not only σ(H) but also another regulatory element that plays a crucial role in the developmental control of S. griseus. Here, we show that an anti-sigma factor antagonist BldG associates with RshA and negatively regulates its activity. The bald phenotype conferred by the overexpression of rshA was restored to the wild-type phenotype by the coexpression with bldG. The in vivo and in vitro protein interaction analyses demonstrated the specific association between RshA and BldG. A bldG mutant exhibited a distinctive bald phenotype and was defective in the σ(H) -dependent transcription activities. The positive regulatory role of BldG regarding the σ(H) activity was verified by an in vitro transcriptional analysis, in which the inhibition of σ(H) -dependent transcription by RshA was abolished by the addition of BldG in a dose-responsive manner. Overall, evidence suggests that BldG serves as a master switch for both stress-response and developmental gene expression based on its association with multiple anti-sigma factors in S. griseus.
authors.affiliation: Life Science Research Center, College of Bioresource Sciences, Nihon University, Fujisawa, Japan.
authors.forename: Hideaki
authors.initials: H
authors.lastname: Takano
authors.forename: Masahiro
authors.initials: M
authors.lastname: Fujimoto
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Urano
authors.forename: Teruhiko
authors.initials: T
authors.lastname: Beppu
authors.forename: Kenji
authors.initials: K
authors.lastname: Ueda
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D020869:Gene Expression Profiling; D015964:Gene Expression Regulation, Bacterial; D055786:Gene Knockout Techniques; D016254:Mutagenesis, Insertional; D011485:Protein Binding; D025941:Protein Interaction Mapping; D013305:Streptomyces griseus / Q000378:metabolism / Q000502:physiology*; D014158:Transcription, Genetic
chemical_list: D001426:Bacterial Proteins