Figure 1.

FtsZ_L169R localizes aberrantly with a greater concentration in rings compared to FtsZ_WT, despite equivalent protein levels. (A) Representative IFM images of WT (WM1074 and W3110) and ftsZ_L169R cells. Cell walls were stained (red) with rhodamine-conjugated wheat-germ agglutinin and FtsZ stained (green) with AlexaFluor 488-conjugated goat α–rabbit recognition of rabbit α-FtsZ. Scale bar = 5 μm. (B) Percentage of mid-log culture cells (n > 100/strain) for indicated strains showing indicated FtsZ localization patterns by IFM as in (A). (C) Representative 3D-SIM images of WT and ftsZ_L169R cells as imaged from the side (along the short axis) or reconstructed views tilted 90º (along the long axis) with FtsZ signal as in (A), with general cell outlines depicted as red dashes. Scale bar = 1 μm. (D) Estimates of percentage of total FtsZ present in representative 3D-SIM images of wild type or ftsZ_L169R rings. Boxes show the median with 35^th and 75^th percentile for each group, and error bars show standard deviation. (E) Representative immunoblot of FtsZ protein levels from mid-exponential cultures of WT or ftsZ_L169R cells with estimated relative band intensities for the image shown, normalized to a low molecular weight segment of the corresponding SDS-PAGE gel stained with Ponceau S. The average relative band intensities from three separate experiments are also shown in bold.