天蓝色链霉菌蛋白酶基因clpP表达的反馈调控机制研究

Little is understood about intrinsic regulatory mechanism of protein degradation of extra-cytoplasmic function（ECF） sigma factors for bacterial cell development and environmental adaptation. In Streptomyces coelicolor, degradation of an ECF sigma factor SigT depends on ClpP/SsrA pathway during cell differentiation. Here we reported that SigT negatively regulated clpP/ssrA expression by direct binding to clpP promoter(clpPp), and SigT-clpPp interaction could be disrupted by secondary metabolites, which accounted for stabilized SigT protein and retarded morphological development in an antibiotic non-producing mutant. Thus a novel regulatory mechanism was revealed that protein degradation of the ECF sigma factor was accelerated in a dual positive feedback manner regulated by secondary metabolites to promote rapid and irreversible development of secondary metabolidm. This ingenious cooperation of intracellular components ensured economical and exquisite control of ECF sigma factor protein level for proper cell differentiation in Streptomyces.