Figure 6.

Some mutations in MreB alter its subcellular distribution. A. Representative cells from wild-type and 11 A22-resistant mreB mutant strains expressing Venus–MreB in the absence of A22. Images, from left to right, correspond to phase contrast, YFP fluorescence, and a merge of the two (Venus–MreB in green; phase contrast in magenta). B. Average one-dimensional intensity of MreB along the long axis of the cell in a mixed population of each strain. To generate this plot, the fluorescence intensity was averaged along the entire cell width at 50 equally spaced points along the cell length (see Experimental procedures). Total intensities were normalized, so that the measured variation from cell to cell is only in the distribution and not in abundance of MreB. At least 500 cells per strain were averaged. C and D. As in (A) and (B) for strains growing in the presence of A22. Asterisks highlight strains in which MreB distribution changes substantially in the presence of A22. All mutant strains shown have the genotype P_mreB::mreB^mutant + P_xyl::venus–mreB^mutant (no wild-type protein is present in any of the mutant strains). Scale bars represent 2 µm.