Asymmetric Division and Differential Gene Expression during a Bacterial Developmental Program Requires DivIVA
Figure 2
DivIVA is required for asymmetric division during sporulation.
(A–F) Polar septum formation was monitored using the fluorescent membrane dye FM4-64 in cells that had initiated sporulation (evidenced by production of GFP under control of the sporulation-specific promoter PspoIIG) for 2 h in (A) otherwise wild type cells (strain PE303); (B) cells expressing divIVA-ssrAEc (strain PE304); expressing sspB alone under an IPTG-inducible promoter (strain PE329) in the absence (C) or presence (D) of IPTG; or co-expressing divIVA-ssrAEc and sspB (strain PE330) in the absence (E) or presence (F) of IPTG. First panel: membranes visualized using FM4-64; second panel: GFP fluorescence indicating sporulating cells; third panel: chromosomes visualized using DAPI; fourth panel: overlay of membrane and GFP; fifth panel: overlay of membrane, GFP, and DNA. Fraction of cells that had initiated sporulation (evidenced by production of GFP) and had elaborated a polar septum is indicated to the right. White arrow in (F) indicates condensed chromosome in a GFP-producing cell; gray arrow indicates an uncondensed chromosome in a non-sporulating cell. (G–L) Polar septum formation was monitored in sporulating cells producing GFP as described above in otherwise (G) wild type cells (strain PE305); (H) ΔminCD (strain PE306); (I) ΔdivIVA (strain PE307); (J) ΔdivIVA ΔminCD (strain PE318); (K) ΔracA (strain PE339); or (L) ΔracAΔminCD (strain PE340). Scale bar: 2 µm.