A gel mobility shift assay showed that SoxR binds specifically to the xcc0300 promoter. RT-PCR in WT and soxR mutant X. campestris showed that xcc0300 expression was induced when wild-type X.campestris culture was treated with 100 μM menadione. However, the MD-mediated induction of xcc0300 expression seen for the wild-type strain was abolished in the soxR mutant. The wild-type pattern of MD-mediated induction of xcc0300 expression was restored in the complemented soxR strain. The xcc0300 transcription start site was determined by primer extension experiments. The putative SoxR box similar to an E.coli SoxR consensus sequence was found in the xcc0300 promoter region. Additionally, RT-PCR experiments in the wild type, a soxR mutant, and a soxR complemented strain showed that soxR expression was autoregulated. EMSA in conjunction with PCR-based site-directed mutagenesis using the soxR promoter fragment confirmed that SoxR box is required for the binding of the SoxR regulator.
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|