Ozaki T, Kumaki Y, Kitagawa R, Ogawa T
Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya 464-8602, Japan.
Microbiology (Reading). 2001 Jan;147(Pt 1):153-9. doi: 10.1099/00221287-147-1-153.
A binding site for DnaA protein was identified in the regulatory region of the aldA gene of Escherichia coli. Specific binding was demonstrated by in vitro assays including filter binding as well as mobility shift in a polyacrylamide gel of the DnaA-DNA complex. In cells growing in minimal medium containing glucose, expression of ss-galactosidase activity from an aldA-lacZ fusion gene was suppressed by oversupply of DnaA protein and was enhanced by reducing the free DnaA level. These results suggest that DnaA protein negatively regulates expression of the aldA gene under these conditions. Despite fairly strong binding, the bound DNA fragment had no consensus 9 bp DnaA binding sequence (DnaA box), and anomalous binding to an AT-rich sequence located close to the transcription start site was revealed by a footprinting experiment.
