The A-factor-binding protein of Streptomyces griseus negatively controls streptomycin production and sporulation.
A-factor, 2-(6'-methylheptanoyl)-3R-hydroxymethyl-4-butanolide, is an autoregulator essential for streptomycin production and sporulation in Streptomyces griseus. S. griseus 2247 that requires no A-factor for streptomycin production or sporulation was found to have a defect in the A-factor-binding protein. This observation implied that the A-factor-binding protein in the absence of A-factor repressed the expression of both phenotypes in the wild-type strain. Screening among mutagenized S. griseus colonies for strains producing streptomycin and sporulating in the absence of A-factor yielded three mutants that were also deficient in the A-factor-binding protein. Reversal of the defect in the A-factor-binding protein of these mutants led to the simultaneous loss of streptomycin production and sporulation. These data suggested that the A-factor-binding protein played a role in repressing both streptomycin production and sporulation and that the binding of A-factor to the protein released its repression. Mutants deficient in the A-factor-binding protein began to produce streptomycin and sporulate at an earlier stage of growth than did the wild-type strain. These mutants produced approximately 10 times more streptomycin than did the parental strain. These findings are consistent with the idea that the intracellular concentration of A-factor determines the timing of derepression of the gene(s) whose expression is repressed by the A-factor-binding protein.
Miyake
K
K
Department of Agricultural Chemistry, Faculty of Agriculture, University of Tokyo, Japan.
Kuzuyama
T
T
Horinouchi
S
S
Beppu
T
T
D015107:4-Butyrolactone / Q000031:analogs & derivatives; D002352:Carrier Proteins / Q000032:analysis / Q000172:deficiency / Q000502:physiology*; D004352:Drug Resistance, Microbial; D006133:Growth Substances / Q000378:metabolism*; D009154:Mutation; D010641:Phenotype; D010860:Pigments, Biological / Q000096:biosynthesis; D012097:Repressor Proteins / Q000502:physiology*; D013171:Spores, Bacterial / Q000502:physiology; D013305:Streptomyces griseus / Q000378:metabolism*; D013307:Streptomycin / Q000096:biosynthesis*; D014157:Transcription Factors / Q000502:physiology*
D002352:Carrier Proteins; D006133:Growth Substances; D010860:Pigments, Biological; D012097:Repressor Proteins; D014157:Transcription Factors; C025035:A-factor (Streptomyces); D015107:4-Butyrolactone; D013307:Streptomycin