title: Phosphorylated AbsA2 negatively regulates antibiotic production in Streptomyces coelicolor through interactions with pathway-specific regulatory gene promoters.
abstract: The AbsA two-component signal transduction system, comprised of the sensor kinase AbsA1 and the response regulator AbsA2, acts as a negative regulator of antibiotic production in Streptomyces coelicolor, for which the phosphorylated form of AbsA2 (AbsA2 approximately P) is the agent of repression. In this study, we used chromatin immunoprecipitation to show that AbsA2 binds the promoter regions of actII-ORF4, cdaR, and redZ, which encode pathway-specific activators for actinorhodin, calcium-dependent antibiotic, and undecylprodigiosin, respectively. We confirm that these interactions also occur in vitro and that the binding of AbsA2 to each gene is enhanced by phosphorylation. Induced expression of actII-ORF4 and redZ in the hyperrepressive absA1 mutant (C542) brought about pathway-specific restoration of actinorhodin and undecylprodigiosin production, respectively. Our results suggest that AbsA2 approximately P interacts with as many as four sites in the region that includes the actII-ORF4 promoter. These data suggest that AbsA2 approximately P inhibits antibiotic production by directly interfering with the expression of pathway-specific regulators of antibiotic biosynthetic gene clusters.
authors.affiliation: Department of Biochemistry & Biomedical Sciences, McMaster University, Health Sciences Centre, 1200 Main St. W., Hamilton, Ontario, Canada.
authors.forename: Nancy L
authors.initials: NL
authors.lastname: McKenzie
authors.forename: Justin R
authors.initials: JR
authors.lastname: Nodwell
mesh_terms: D000199:Actins / Q000235:genetics / Q000378:metabolism; D000880:Anthraquinones / Q000378:metabolism; D000900:Anti-Bacterial Agents / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D015153:Blotting, Western; D047369:Chromatin Immunoprecipitation; D015964:Gene Expression Regulation, Bacterial; D015801:Helminth Proteins / Q000235:genetics / Q000378:metabolism; D008957:Models, Genetic; D010766:Phosphorylation; D011353:Prodigiosin / Q000031:analogs & derivatives / Q000378:metabolism; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D048372:Streptomyces coelicolor / Q000235:genetics / Q000378:metabolism*; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D000095622:Benzoisochromanequinones
chemical_list: D000199:Actins; D000880:Anthraquinones; D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D015801:Helminth Proteins; D011353:Prodigiosin; D015534:Trans-Activators; D014157:Transcription Factors; C431645:ACTII protein, Echinococcus granulosus; C433524:AbsA2 protein, Streptomyces coelicolor; C104042:RedZ protein, Streptomyces coelicolor; C047347:undecylprodigiosin; C013390:actinorhodin; D000095622:Benzoisochromanequinones