Fig. 4.

Cardiac vegfaa overexpression elicits an ectopic heart regeneration program. (A and B) Tiled images of cmlc2:CreER;βact2:BS-vegfaa hearts 14 dpi with vehicle or tamoxifen. Arrowheads indicate Mef2⁺/PCNA⁺ nuclei. Mef2⁻/PCNA⁺ nuclei are likely to be cycling epicardial cells, endothelial cells, fibroblasts, or inflammatory cells. (C) CM proliferation 14 dpi with vehicle (n = 10) or tamoxifen (n = 8). Error bars indicate SEM (***P < 0.001, Mann–Whitney U test). (D and E) cmlc2:CreER;βact2:BS-vegfaa;gata4:EGFP hearts 14 dpi with vehicle or tamoxifen. Arrowheads indicate gata4⁺ CMs. (F and G) Images of cmlc2:CreER;βact2:BS-vegfaa;LENP2:EGFP hearts 14 dpi with vehicle or tamoxifen. Arrowheads indicate LENP2⁺ cells. Tnnt marks CMs. Boxes correspond to the region magnified in adjacent panels. (H and I) Images of cmlc2:CreER;βact2:BS-vegfaa;tcf21:DsRed hearts 14 dpi with vehicle or tamoxifen. (J and K) In situ hybridization for raldh2 on ventricular sections. Violet staining indicates expression. [Scale bars: B, H, and J, 100 μm (also apply to A, I, and K, respectively); D and F, 100 μm (Left) and 25 μm (Right) (also apply to E and G, respectively).]