Positive feedback regulation of stgR expression for secondary metabolism in Streptomyces coelicolor

J Bacteriol. 2013 May;195(9):2072-8. doi: 10.1128/JB.00040-13. Epub 2013 Mar 1.

Abstract

LysR-type transcriptional regulators (LTTRs) compose a large family and are responsible for various physiological functions in bacteria, while little is understood about their regulatory mechanism on secondary metabolism in Streptomyces. Here we reported that StgR, a typical LTTR in Streptomyces coelicolor, was a negative regulator of undecylprodigiosin (Red) and γ-actinorhodin (Act) production in the early developmental phase of secondary metabolism by suppressing the expression of two pathway-specific regulator genes, redD and actII-orf4, respectively. Meanwhile, stgR expression was downregulated during secondary metabolism to remove its repressive effects on antibiotic production. Moreover, stgR expression was positively autoregulated by direct binding of StgR to its own promoter (stgRp), and the binding site adjacent to translation start codon was determined by a DNase I footprinting assay. Furthermore, the StgR-stgRp interaction could be destroyed by the antibiotic γ-actinorhodin produced from S. coelicolor. Thus, our results suggested a positive feedback regulatory mechanism of stgR expression and antibiotic production for the rapid and irreversible development of secondary metabolism in Streptomyces.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacterial Proteins / chemistry
  • Bacterial Proteins / genetics*
  • Bacterial Proteins / metabolism*
  • Base Sequence
  • Binding Sites
  • Feedback, Physiological*
  • Gene Expression Regulation, Bacterial*
  • Helix-Turn-Helix Motifs
  • Molecular Sequence Data
  • Promoter Regions, Genetic
  • Protein Binding
  • Streptomyces coelicolor / chemistry
  • Streptomyces coelicolor / genetics
  • Streptomyces coelicolor / metabolism*
  • Transcription Factors / chemistry
  • Transcription Factors / genetics*
  • Transcription Factors / metabolism*

Substances

  • Bacterial Proteins
  • Transcription Factors