Defects in the final stage of primary-septum formation in cdh1Δ and IQG1Δ42 cells. Strains YEF473A (A, wild type), KO255 (B, cdh1Δ), and GT124 (C, IQG1Δ42) were examined by electron microscopy after growth at 24°C; representative images are shown. Bar, 0.5 μm.