title: Regulation of myo-inositol catabolism by a GntR-type repressor SCO6974 in Streptomyces coelicolor.
abstract: Myo-inositol is important for Streptomyces growth and morphological differentiation. Genomic sequence analysis revealed a myo-inositol catabolic gene cluster in Streptomyces coelicolor. Disruption of the corresponding genes in this cluster abolished the bacterial growth on myo-inositol as a single carbon source. The transcriptions of these genes were remarkably enhanced by addition of myo-inositol in minimal medium. A putative regulatory gene SCO6974, encoding a GntR family protein, is situated in the cluster. Disruption of SCO6974 significantly enhanced the transcription of myo-inositol catabolic genes. SCO6974 was shown to interact with the promoter regions of myo-inositol catabolic genes using electrophoretic mobility shift assays. DNase I footprinting assays demonstrated that SCO6974 recognized a conserved palindromic sequence (A/T)TGT(A/C)N(G/T)(G/T)ACA(A/T). Base substitution of the conserved sequence completely abolished the binding of SCO6974 to the targets demonstrating that SCO6974 directly represses the transcriptions of myo-inositol catabolic genes. Furthermore, the disruption of SCO6974 was correlated with a reduced sporulation of S. coelicolor in mannitol soya flour medium and with the overproduction of actinorhodin and calcium-dependent antibiotic. The addition of myo-inositol suppressed the sporulation deficiency of the mutant, indicating that the effect could be related to a shortage in myo-inositol due to its enhanced catabolism in this strain. This enhanced myo-inositol catabolism likely yields dihydroxyacetone phosphate and acetyl-CoA that are indirect or direct precursors of the overproduced antibiotics.
authors.affiliation: State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China.
authors.forename: Lingjun
authors.initials: L
authors.lastname: Yu
authors.forename: Shuxian
authors.initials: S
authors.lastname: Li
authors.forename: Wenyan
authors.initials: W
authors.lastname: Gao
authors.forename: Yuanyuan
authors.initials: Y
authors.lastname: Pan
authors.forename: Huarong
authors.initials: H
authors.lastname: Tan
authors.forename: Gang
authors.initials: G
authors.lastname: Liu
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D001665:Binding Sites; D002244:Carbon / Q000378:metabolism; D004269:DNA, Bacterial / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D007294:Inositol / Q000235:genetics / Q000378:metabolism*; D005810:Multigene Family; D009154:Mutation; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism; D013171:Spores, Bacterial / Q000235:genetics; D048372:Streptomyces coelicolor / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism* / Q000502:physiology
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; C081598:GntR protein, E coli; D012097:Repressor Proteins; D007294:Inositol; D002244:Carbon