Figure 3
DegU-regulation of flgB. Cells were grown in MC medium. Their β-galactosidase activities were determined as described previously [45]. A. Left (swrAA) and right (swrAA+) panels show representative results of the β-galactosidase assays. All strains carry the flgB-lacZ (F1D) fusion. Filled circles, wild type (OAM385 in the left and OAM386 in the right); squares, degS (OAM388 in the left and OAM390 in the right); open circles, degU (OAM387 in the left and OAM389 in the right); triangles, degU32, (OAM391 in the left). The numbers on the x axis represent the growth time in hours relative to the end of vegetative growth (T0). B. Transcription of various flgB-lacZ fusions in each genetic background. The open rectangles and filled circles on the line indicate the DegU-binding motifs and introduced mutations, respectively. The mutant fusions tested included the F1 to F3 series of fusions (the 3' ends are +38) as well as F1D and F2D (the 3' ends are +264), in which increasing deletions were made from the 5' end, and the M series, in which point mutations (small letters indicate replaced nucleotides) were introduced. F1MD and F1M1 contain the same mutation. All fusions were constructed by cloning various PCR products into pIS284. Consequently, all strains are derivatives of OAM385 (amyE::flgB-lacZ). The oligonucleotides used to construct the pIS284 derivatives are shown in Additional file 1. The activities were assayed hourly from T-1 through to T3. At least three independent assays were performed and the averages of the peak values are shown. Standard deviations did not exceed 20%. The "degS", "degU" and "degU32" columns show the β-galactosidase activities of each fusion in the degS::Emr, degU::Kmr and degU32 backgrounds, respectively. ND means no data. C. Schematic representation of the regulation of flgB. Arrows and a curved T-bar indicate activation and inhibition, respectively.