title: The RNA polymerase omega factor RpoZ is regulated by PhoP and has an important role in antibiotic biosynthesis and morphological differentiation in Streptomyces coelicolor.
abstract: The RNA polymerase (RNAP) omega factor (ω) forms a complex with the α₂ββ' core of this enzyme in bacteria. We have characterized the rpoZ gene of Streptomyces coelicolor, which encodes a small protein (90 amino acids) identified as the omega factor. Deletion of the rpoZ gene resulted in strains with a slightly reduced growth rate, although they were still able to sporulate. The biosynthesis of actinorhodin and, particularly, that of undecylprodigiosin were drastically reduced in the ΔrpoZ strain, suggesting that expression of these secondary metabolite biosynthetic genes is dependent upon the presence of RpoZ in the RNAP complex. Complementation of the ΔrpoZ mutant with the wild-type rpoZ allele restored both phenotype and antibiotic production. Interestingly, the rpoZ gene contains a PHO box in its promoter region. DNA binding assays showed that the phosphate response regulator PhoP binds to such a region. Since luciferase reporter studies showed that rpoZ promoter activity was increased in a ΔphoP background, it can be concluded that rpoZ is controlled negatively by PhoP, thus connecting phosphate depletion regulation with antibiotic production and morphological differentiation in Streptomyces.
authors: Institute of Biotechnology-INBIOTEC, Avda. Real 1, 24006 León, Spain.
authors: Fernando
authors: F
authors: Santos-Beneit
authors: Mónica
authors: M
authors: Barriuso-Iglesias
authors: Lorena T
authors: LT
authors: Fernández-Martínez
authors: Miriam
authors: M
authors: Martínez-Castro
authors: Alberto
authors: A
authors: Sola-Landa
authors: Antonio
authors: A
authors: Rodríguez-García
authors: Juan F
authors: JF
authors: Martín
mesh_terms: D000880:Anthraquinones / Q000378:metabolism; D000900:Anti-Bacterial Agents / Q000096:biosynthesis*; D001426:Bacterial Proteins / Q000378:metabolism*; D012321:DNA-Directed RNA Polymerases / Q000378:metabolism*; D017353:Gene Deletion; D015964:Gene Expression Regulation, Bacterial; D005816:Genetic Complementation Test; D011353:Prodigiosin / Q000031:analogs & derivatives / Q000096:biosynthesis; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D012808:Sigma Factor / Q000096:biosynthesis* / Q000235:genetics; D048372:Streptomyces coelicolor / Q000235:genetics* / Q000254:growth & development*; D000095622:Benzoisochromanequinones
chemical_list: D000880:Anthraquinones; D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D012321:DNA-Directed RNA Polymerases; D011353:Prodigiosin; D012808:Sigma Factor; C061064:PhoP protein, Bacteria; C047347:undecylprodigiosin; C013390:actinorhodin; D000095622:Benzoisochromanequinones