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Fig. S2
The normal pattern of cell proliferation during fin regeneration in zebrafish. (A) Tissue sections of regenerating zebrafish fin in which proliferating cells were detected by the Edu incorporation. EdU labelling lasted for 6 hrs before sampling. For quantitative reproducibility, the 3rd - 5th fin rays from the dorsal or ventral side were used for making sections. “Regenerate” indicates the region distal to amputation plane, and “Proximal non-regenerated region” indicates the region within 100 mm proximal to the amputation plane. Only a few Edu-positive cells were observed at 1 dpa, but the number rapidly increased at 2 dpa both in the regenerating epidermis and mesenchyme. dpa, days post amputation. Scale bar, 100 µm. (B) Quantification of the number of Edu-positive cells in the regenerates that are distal to the amputation plane. Note that the activation of cell proliferation was not detected at 1 dpa in sections of the ray region, which is consistent with previous observations that the epidermal cell proliferation was localised in the inter-ray epidermis (Gauron et al., 2013; Meda et al., 2016). Cell counting was performed on 20 sections (5 sections each from 4 different fish). Error bars represent mean ± s.e.m. Student’s t test was performed to assess statistical significance. **p < 0.001 (C) Quantification of the number of Edu-positive cells in the non-regenerating region (within 100 µm from the amputation plane). Cell proliferation in the proximal region was not changed in the epidermis during the course of regeneration. Cell proliferation in the mesenchyme was rather decreased due to the fin outgrowth and the shift of proliferation zone to the distal place. Error bars represent mean ± s.e.m. Student’s t test was performed to assess statistical significance. n.s., not significant. **p < 0.001