Fig. 4

Fig. 4

Csrp3 deficiency reduces CM proliferation and impedes zebrafish heart regeneration. A Representative images of the recovered/ unrecovered heart of 218A mutant larvae at 4 dpa/7 dpf. Scale bars, 20 μm. B Quantification of the regeneration ratio of ablated wild-type, + /218A, and 218A hearts at 4 dpa/7 dpf. The numbers of larvae analyzed are indicated. Binomial test, ****P < 0.0001, NS, non-significant. C Immunostaining of the mitotic marker phospho-histone H3 (pH3) revealed a significant decrease of proliferating CMs in 218A larval hearts at indicated stages. Scale bars, 20 μm. D Quantification of the number of pH3⁺ CMs in ablated wild-type and 218A hearts. N = 18 each. Data are presented as mean ± SD, Student’s t-test, ****, p < 0.0001. E Representative AFOG staining of cryoinjured ventricles from wild-type, + /218A, and 218A fish at 30 dpci. Scale bars, 100 μm. F Quantification of ventricular scar area ratio in wild-type, + /218A, and 218A fish at 30 dpci. N = 7, 6, 7, respectively. Student’s t-test, ***, p < 0.001, NS, non-significant. G Representative confocal images of cryoinjured ventricle sections from wild-type and 218A adult fish at 7 dpci stained with anti-PCNA (green) and anti-Mef2c (red) antibodies. Box areas are amplified. Arrowheads indicate proliferating CMs. Scale bars, 100 μm. H Quantification of CM proliferation index at border zone and injury site of ventricle sections at 7 dpci. N = 6 each. Student’s t-test, ***, p < 0.001