Figure 3.

Complex regulation of lrp translation by GcvB. (A) Schematic representation of various lrp-lacZ deletions and mutant fusions. The regions of pairing of MicF and DsrA are shown with horizontal lines. The positions of the point mutations are shown with heavy lines, with the sequence changes for mt4, mt8 and mt11 shown below the line. The precise end-point of each deletion is shown in Supplementary Figure S3. (B) Cells were grown and assayed as in Figure 2A (OD₆₀₀ of between 2.5 and 3). β-galactosidase activity was determined from cells with lrp (HL1071), lrp S1 (HL1517), lrpS3 (HL1701), lrpS4 (HL1702), lrpS5 (HL1703) and lrp S2 (HL1518)-lacZ translational fusions in the presence of plasmids overexpressing GcvB (black bars) or with the pBRplac empty vector (white bars); the chromosomal copy of gcvB was deleted in all of these strains. Percentage regulation by GcvB was compared to the vector control for each deletion. Error bars indicate standard deviation. (C) Cells were grown and assayed as in Figure 2B. β-galactosidase activity was determined from cells with the following translational fusions: lrp (HL1071), lrp mt9 (HL1694), lrp mt11 (HL1731), lrp mt8 (HL1693), lrp mt4 (HL1149), lrp mt12 (HL1732) and lrp mt10 (HL1717).