Fig. 4: DivIC spatially regulates PBP-dependent PG synthesis during cell division.

a Fluorescence microscopy images of SH1000 and ΔdivIC (SJF5450) cells grown for 2 h with and without IPTG and subsequently treated with HADA followed by ADA-DA (5 min each) to follow PG synthesis. Arrowheads show cells where PG synthesis is mainly observed at the septum. Arrows show exemplar cells with PG synthesis at the septum and cell periphery. Cells were counter-stained with NHS-ester 555 to image cell walls. b Fluorescence ratios (FR) are the product of fluorescence signal at the septum divided by the signal at the cell periphery in cells with incomplete septa after incubation with ADA-DA. c Localisation of GFP-PBP2 in SH1000 (SJF5541) and ΔdivIC (SJF5560) cells growing with and without IPTG for 2 h and incubated with HADA for 30 min to label PG. d FR between GFP-PBP2 fluorescent signal at the septum versus the cell periphery in cells with incomplete septa. e Localisation of FtsW-GFP in SH1000 (SJF5768) and ΔdivIC (SJF5767) cells growing with and without IPTG for 2 h and incubated with HADA for 30 min to label PG. f FR between FtsW-GFP fluorescent signal at the septum versus the cell periphery in cells with incomplete septa. Each circle indicates a single cell, lines are mean of an n = 100. P-values were determined by Mann–Whitney U-tests (****P < 0.0001; ***P < 0.0002). All images are average intensity projections of z stacks. Scale bars, 2 μm. Data is representative of two independent experiments.