Fig. 4.

Fig. 4. Inhibition of AP-1 activity compromises heart regeneration.

(A) Anti-phospho-c-Jun antibody staining of regenerating hearts from control and tnfα mutant fish carrying tcf21:nucGFP at 7 dpa. Dotted lines and asterisks indicate injury border and colabeled cells, respectively. Scale bar, 50 μm. (B) Schematic of Epi/FB-specific inhibition of AP-1 activity. (C) Representative image of hearts from 7-dpa control and Epi/FB:dnAP-1 hearts carrying tcf21:nucGFP, respectively. Orange boxes mark the peripheral area, and the white boxes mark the injury area, under which are their respective zoom-in images. Scale bar, 50 μm. (D and E), Quantification of the number of tcf21:nucGFP-positive cells in the peripheral and injury area, respectively. n = 5. (F) Concurrent RNAscope in situ hybridization for postnb and immunostaining for MF20 in the 7-dpa control and Epi/FB:dnAP-1 hearts. White boxes mark the injury area, under which are their respective zoom-in images. Scale bar, 50 μm. (G) Quantification of the postnb⁺ area in the wound on sections. n = 5. (H) Heart sections are stained with AFOG at 30 dpa. Black boxes mark the injury area. Scale bar, 100 μm. (I) Quantification of scar area at 30 dpa. n = 5. (J) Schematic of EC-specific inhibition of AP-1 activity. (K) Concurrent RNAscope in situ hybridization for fosl1a and immunostaining for MF20 in the 7-dpa hearts. Scale bar, 50 μm. (L) Quantification of the number of fosl1a-positive dots in the white boxed area between EC:dnAP-1 and control hearts. n = 5. White dotted lines indicate approximate injury border. P value calculated with two-tailed Student’s t test. **P < 0.01. *P < 0.05.