FIGURE 8

FIGURE 8

Distribution of HCS-cells in alf mutants and during ontogenesis of wild type zebrafish. (A) Projections of 5-HT-positive cells (white dots) in an uninjured alf fin based on immunofluorescence staining of the rays. Autofluorescence of tissue with bones (pink). (A’) Zoom of the framed region in panel (A) shows higher density of HCS-cells in bifurcation interrays, like in wild type fins. (B) Quantification of HCS-cell density in alf fins versus wild-type fins shows a significantly higher overall density of HCS-cells in alf fins (113 ± 60 vs. 210 ± 30 cells per mm²). N ≥ 3. ^∗p < 0.05. (C) Quantification of HCS-cell density in primary interray (PI) vs. bifurcation interray (BI) in wild-type versus alf fins. Density difference is present in alf fins (104 ± 20 vs. 426 ± 196 cells per mm² in wild type and 166 ± 112 vs. 729 ± 277 in alf). N ≥ 3. ^∗∗∗p < 0.001. (D) Projections of 5-HT-positive cells in fins at different ages ranging from 14 days to 24 months post-fertilization (dpf and mpf), based on immunofluorescence staining. For juvenile stages, the developmental stage is shown as standardized standard length (Parichy et al., 2009). (E) Quantification of density of 5-HT-positive cells in caudal fins during post-embryonic ontogenesis. While the density is lower at larval stages, once fins switch to a bi-lobed morphology, the concentration of HCS-cells increases and remains constant through the adult life of the fish (7 ± 5 at 14 dpf; 38 ± 30 at 21 dpf; 68 ± 25 at 30 dpf; 152 ± 60 at 60 dpf; 164 ± 95 at 12 months and 140 ± 82 at 24 months). N ≥ 2.