Transcriptional repression of the dnaA gene of Escherichia coli by dnaA protein.

The promoter region of the dnaA gene and of a gene which encodes a 16 kDa protein contain sites which are recognized and bound by dnaA protein. Using assays of run-off transcription of restriction fragments, purified dnaA protein specifically repressed transcription from both dnaA promoters and from the promoter for the 16 KD gene to almost undetectable levels. This repressive effect was observed at levels of dnaA protein required for specific binding of dnaA protein to restriction fragments containing the promoters for these genes. These results indicate that transcription of these genes is regulated by binding of dnaA protein to the promoter regions of these genes.