Fynb is responsible for epimorphic regeneration. (A) RT-PCR of SFKs. hck and lyn, hematopoietic-specific SFKs, are negative controls. (B) Tg(krt4:GFP) larvae at 3 dpf were used for flow cytometry. GFP high fractions (boxed with a blue line) were sorted. Cells from wild-type larvae were used to set the background level of autofluorescence. (C) RT-PCR of fynb and yes with/without MOs. ef1-α is the loading control. (D) Representative pictures at 3 d after wounding. (E) Quantification of regenerated tail fin length at 3 d after wounding (control [Ctrl]: 19 larvae; fynb MO1: 20 larvae; fynb MO2: 21 larvae; yes MO: 20 larvae; fynb MO1/yes MO: 16 larvae). (F) In situ hybridization of fynb mRNA in 2-dpf larvae. The tail fin in the blue box is magnified on the right. (G) Ratio images of pSFK/krt4-tdTomato in control and fynb morphants. (H) Mitotic cells were detected by antibody staining for phosphorylated histone H3 (H3P) at 36 h after wounding. (I) Quantification of blastemal proliferation at 36 h after wounding (control: 14 larvae; fynb MO1: 12 larvae). (J) A proposed model showing early wound signaling-mediated regulation of late regeneration. (E and I) *, P < 0.05; one-way ANOVA with Dunnett’s posttest (E) and two-tailed unpaired t test (I). Horizontal lines indicate means. Bars, 50 µm.