Figure 4

Quantification of localized FHF lineage labeling in the adult zebrafish ventricle. (A) Schematic illustration of the adult zebrafish heart with three planes of transversal sections across the region of the ventricle base and the atrium. (B) Quantification of ZsYellow-positive cardiomyocyte area in the Tropomyosin-demarcated myocardium indicates predominant labeling in the atrium?distal ventricle, while the atrium?proximal ventricle only retained low numbers of ZsYellow-labeled cells. Note the scarce atrium labeling. One-Way ANOVA test followed by Tukey?s multiple comparison test, *** p < 0.0001 (n = 8 hearts, 2?3 sections each as per (A)). (C?E) Three sections (a, b, c) of the same heart with the largest tissue area were selected for the quantification of ZsYellow-labeled cardiomyocytes. The dotted line depicts a possible boundary of high- versus low-density ZsYellow labeling. Note that nonetheless, no sharp boundary separates the two areas. Asterisk denotes rare atrial ZsYellow clones throughout sections. Scale bar: 200 µm.