The Regulatory Function Of StgR In Streptomyces Ceolicolor

Streptomyces coelicolor is a kind of soil-dwelling bacteria with a complex lifecycle and abundant secondary-metabolic products including red-pigmented tripyrrole undecylprodigiosin Red, blue pigmented polyketide actionorhodin Act, lipopeptide calcium-dependent antibiotic, CDA and Mmy, which have great medical value.stgR is a classical member of LTTR family, which had been found its inhibition in the transcription system. In this research, we firstly constructed a stgR deletion mutant in Streptomyces coelicolor by PCR-targeting strategy, and which could cause an earlier switch from vegetative mycelia to aerial mycelia and higher expression of chpE than that in the wild type.Loss of stgR also resulted in accelerated and enhanced production of antibiotics, actinorhodin, and undecylprodigiosin and increased expression of act2-orf4and redD. These results suggested that stgR play a negative role in morphological transition and secondary metabolism.The q-PCR experiment revealed that the transcription level of gene of chpE, actⅡ-orf4and redD in the stgR mutant is much higher than that in the wild type.The further research indicated that stgR played the role of negative effect on its-self promoter by constructing the pIJ8630-stgRp then lead into the mutant and wild type respectively.