Immunofluorescent Staining of Fish Tissues

Fish samples were fixed in formalin solution (Sigma-Aldrich) and sectioned at 5-µm thickness using a microtome, followed by hematoxylin and eosin (H&E) (Sigma-Aldrich) and immunofluorescent staining. Immunofluorescent staining was carried out as previously described (Yan et al., 2015 (link)). The primary antibodies used included rabbit anti-PCNA at a dilution of 1:200 (Santa Cruz Biotechnology, SC-7907), rabbit anti-Caspase 3 at a dilution of 1:200 (BD Biosciences, 559565), mouse anti-GFP at a dilution of 1:500 (Millipore, MAB3580), rabbit anti-RFP at a dilution of 1:100 (Abcam, ab62341), mouse anti-DsRed at a dilution of 1:100 (Santa Cruz Biotechnology, sc390909) and mouse anti-Cre antibody at a dilution of 1:200 (Abcam, ab24607).