FIG. 3.

Immunofluorescence of ponA-FLAG (A, B, and C) or wild-type (D) cells grown in 2× YT medium at 37°C. The figure shows immunodetection of the FLAG epitope only (red), staining of cell walls and septa with Oregon green-conjugated WGA (green), and an overlay of those images showing simultaneously visualized PBP1-FLAG and cell walls and septa. Arrows point to PBP1-FLAG localization at midcell; arrowheads show PBP1-FLAG bands that colocalize with completed septa between two cells in a chain (completed septa stain very brightly with Oregon green-WGA, in contrast to nascent septa at midcell, which appear as faint green bands; see also Materials and Methods). Bar, 10 μm.