Fig. 5.
The frlB-frlO intergenic region (IfrlB-frlO) decreases the expression downstream of frlB. (A) Analysis of the binding of FrlR to IfrlB-frlO by EMSA. A 0.5 nM concentration of 5′-DIG-labeled IfrlB-frlO was incubated without (−) or with 400 to 600 nM FrlRcHis. (B) Schematic illustration of the reporter gene constructs. The FrlR-independent hpaII promoter was cloned in front of the lacZ reporter gene in wild-type (SK2) and ΔfrlR (SK4) constructs. Further constructs with the frlB gene and IfrlB-frlO downstream of PhpaII followed by lacZ (SK1 [wild type] and SK3 [ΔfrlR]) were generated. (C) Measurement of promoter activity by β-galactosidase assay. Strains were cultivated in M9-Amadori medium, and at the indicated time points, the β-galactosidase activity was measured. Standard deviations are shown as error bars.