Fig. 3

(A–D) 2D (mid-sagittal sections) (A and C) and maximum intensity projections of confocal z-stacks (B and D) of 82 hpf klf2 WT (A–B) and mutant (C–D) hearts stained with Acridine Orange to visualize cell death; arrows point to extruding cardiomyocytes. (E–H) Confocal images of 96 hpf klf2 WT (E and G) and mutant (F and H) hearts to visualize cardiomyocyte proliferation. (I) Number of mVenus-gmnn positive ventricular and atrial cardiomyocytes in 96 hpf klf2 WT and mutant hearts; dots represent individual hearts; values represent means ±SEM; ***p≤0.001, ns (not significant), by Student’s t-test. (J–K’’) Mid-sagittal confocal sections of 96 hpf klf2 WT (J) and mutant (K) hearts. Higher magnification images of the outer curvature of the ventricular wall (white dashed boxes) in (J) and K) are shown in (J’), (J’’), (K’) and (K’’); arrows point to ectopic accumulation of Cdh2-EGFP proteins on the apical side of cardiomyocytes. (L–M’) 2D confocal views of 96 hpf klf2 WT (L) and mutant (M) hearts. Magnified images of dashed boxes in (L) and (M) are shown in (L’) and (M’), respectively. Arrows point to mislocalized Cdh2-GFP on the apical side of cardiomyocytes; V: ventricle, At: atrium; scale bars, 50 µm.