Promoter-lacZ fusion assays showed that NtrC controls gdhA expression in response to nitrogen availability. The transcription initiation site was identified by performing a primer extension analysis of the gdhA transcript. DNase I footprinting of the gdhA promoter region was used to identify the NtrC binding site. In vitro titration assays confirmed that NtrC directly represses the transcription of gdhA. Site-directed mutagenesis in conjunction with DNase I footprinting confirmed the binding specificity of the NtrC to its target site.
Regulated genes for each binding site are displayed below. Gene regulation diagrams show binding sites, positively-regulated genes, negatively-regulated genes, both positively and negatively regulated genes, genes with unspecified type of regulation. For each indvidual site, experimental techniques used to determine the site are also given.
|Site sequence||Regulated genes||Gene diagram||Experimental techniques||TF function||TF type|