Fig. 4

sp7 expression analysis in Chi/+ and WT caudal fins. (A) RT-qPCR analysis showed increased expression of sp7 at 3 dpa and decreased level at 5 dpa in both WT and mutant. No differences in sp7 expression between genotypes (n ≥ 3 pools of six caudal fins for each genotype) were detected. dpa: days post amputation. (B) sp7:GFP+ cells were increased in number at day 0 and 3 dpa in Chi/+ respect to WT (n = 5 zebrafish for each genotype). (C) Representative images of sp7:GFP localization in the fin rays of WT and Chi/+ at day 0, 3 and 5 dpa. For each time point is indicated the corresponding distribution analysis (GFP distribution along the segment at day 0, and from the amputation plane at 3 and 5 dpa). No significant differences were found between WT and Chi/+, but an accumulation of sp7:GFP+ cells could be observed at the tip of the fin rays at 3 dpa (arrowhead). The amputation plane is indicated by the white dotted line. Scale bar: 100 µm. In the graphs, each dot represents a single value: circle for WT and square for Chi/+. * P < 0.05, ** P < 0.01, # P < 0.0001.