Figure 1. Spatial and temporal distributions of 5mC and 5hmC during regeneration of zebrafish fin. (A–C) Longitudinal sections of wild type fin regenerates that were immunohistochmically stained with antibodies against 5mC (red) and 5hmC (green) at 0 (A), 30 (B), and 72 hpa (C). The fluorescent signals of DAPI (blue) indicate the presence of nuclei. Uniform distributions of 5mC and 5hmC fluorescent signals were observed in the intra-ray cells at 0 hpa (A). The fluorescent signals of both 5mC and 5hmC in the balstema cells and cells within 150 μm proximal to the amputation plane at 30 hpa were lower than those at 0 hpa (B). At 72 hpa, the 5mC level in the blastema cells was almost restored, whereas the 5hmC level in the blastema cells was still lower than that at 0 hpa (C). White lines indicate the amputation planes. Dashed lines outline the basement membrane, which shows the boundary between the epidermis and blastema. Scale bars represent the distance from the amputation plane. (D andE): Quantification of the relative fluorescent signal of 5mC or 5hmC at 0, 30, and 72 hpa. Relative 5mC intensity at 30 hpa, and relative 5hmC intensities at 30 and 72 hpa, were significantly lower than those at 0 hpa. In contrast, relative 5mC intensity at 72 hpa was almost the same as that at 0 hpa. * p < 0.001 by Student’s t- test. Error bars represent the standard error.