Key: Click on "details" for more information on a particular experiment or article. "Result" is a short description of the experiment result. "Methods" use a ontology to describe the methods of the experiment.
  Results:Regulatory site mappingMethods:Footprinting
To further elucidate the mechanism of transcription repression mediated by ToxR binding to the ompT promoter, we performed DNase I footprinting analysis. A restriction fragment corresponding to the -165 to +104 region of the ompT promoter, which harbours the putative ToxR-binding site as suggested by the transcriptional fusion studies as well as the gel mobility shift experiments, was radiolabelled on one strand and incubated with E. coli membranes containing ToxRS. The binding reactions were next treated with DNase I and subjected to electrophoresis on a denaturing polyacrylamide gel to identify the region protected from DNase I digestion as a result of ToxR binding. Membranes containing ToxRS (ToxRS+) protected a large region corresponding to the -30 to -95 region of the ompT promoter. The large size of the ToxR footprint (60bp) suggests that multiple ToxR molecules are involved in binding.
Experiment Elements
site: ToxR-protected region at ompT Vibrio cholerae
gene: ompT Vibrio cholerae
regulator: ToxR Vibrio cholerae
Li CC,Crawford JA,DiRita VJ,Kaper JB
Molecular cloning and transcriptional regulation of ompT, a ToxR-repressed gene in Vibrio cholerae.Mol Microbiol 2000 Jan;35(1):189-203. (details)
PubMed: 10632889