Fig. 2

Fig. 2 hapln1a+ cells form cellular structures in advance of coronary sprouts during vascularization.

a Whole-mount view of hapln1a⁺ cells and deltaC:EGFP⁺ coronary endothelial cells on hapln1a:mCherry-NTR;deltaC:EGFP ventricular surface (opposite the atrioventricular junction) at 7 weeks post-fertilization (wpf). The boxed area is enlarged. Arrows indicate deltaC:EGFP⁺ cells lining with hapln1a⁺ cells. n = 50 animals. Scale bar, 100 µm. b Representative images of hapln1a⁺ cells located ahead of deltaC:EGFP⁺ cells in the juvenile ventricular surface. Arrows indicate coronary tips. Total 50 animals have been examined from 3 independent experiments with similar results. Scale bar, 50 µm. c The three position types of hapln1a⁺ cells according to their localization with coronary sprouts in the juvenile heart surface: hapln1a⁺ cells behind (I), parallel (II), and leading (III) deltaC⁺ cells. Arrows, front of deltaC⁺ cells. Arrowheads, front of hapln1a⁺ cells. Scale bar, 50 µm. d Quantification of the three types of positions from experiments in c. I, 6%; II, 12%; III, 82%. n = 23 animals. Mann–Whitney rank-sum test (Two-sided). Data are presented as mean values ± SD. Source data are provided as a Source Data file. e Growing deltaC⁺ cell extensions and macrophages (IB4⁺) in juvenile hearts. Arrowheads represent IB4⁺ macrophages flanking coronary vessels. Arrows represent deltaC⁺ vessel extensions. n = 8 animals. Scale bar, 50 µm. f Growing deltaC⁺ cell extensions and AcT-Hu⁺ nerves in juvenile hearts. Arrows represent EGFP⁺ vessel extensions. n = 5 animals. Scale bar, 50 µm. g Growing deltaC⁺ cell extensions and gata4⁺ CMs in juvenile hearts. Arrows represent deltaC⁺ vessel extensions outside gata4⁺ CM area. Arrowheads represent deltaC⁺ vessel extensions embedded in gata4⁺ CM area. n = 8 animals. Scale bar, 50 µm.