Transcription from the chiC promoter, directing expression of the chitinase gene, chiC, in Streptomyces coelicolor, was analyzed using xylE reporter gene and high-resolution S1-nuclease mapping. The transcription from the chiC promoter was induced by chitin, and this induction was dramatically reduced in the S. coelicolor chiR-disrupted strain. This indicated a dependence of chiC expression upon the chiR gene encoding a response regulator protein. To investigate this relationship, the S. coelicolor ChiR was overproduced using Escherichia coli T7 RNA polymerase expression system. However, gel mobility shift-assay with such a purified ChiR showed no binding in the chiC promoter region, which indicates a lack of specific phosphorylation of E. coli overproduced ChiR that is necessary for DNA-binding activity of response regulators.