Analysis of the regulatory region of the Escherichia coli nupG gene, encoding a nucleoside-transport protein.

The S1-mapping procedure, when applied to an 800-bp fragment upstream of the nupG structural gene of Escherichia coli revealed one transcription-initiation site. The corresponding promoter is negatively regulated by the cytR and the deoR repressors. The expression of the gene is activated by the complex between cAMP and its receptor protein. In strains lacking cAMP the promoter expression is reduced and it is no longer regulated by the cytR repressor, whereas the deoR regulation is retained.