FIGURE 5

FIGURE 5

Scattered distribution of HCS-cells in uninjured adult fins. (A,B) Whole-mount immunofluorescence staining of uninjured fins for serotonin (5-HT; green) and SV2 (red). Tissue autofluorescence allows visualization of bony rays (blue). (A’,A”) Higher magnifications of different fin regions. The area immediately above a ray bifurcation shows a higher density of HCS-cells. N = 12. (B) A zoom of the interray region marked by an elongated frame in panel (A). Aligned multicellular aggregates of SV2-positive and 5-HT-negative cells represent mechanosensory neuromasts. (C–E”) Whole mount in situ hybridization of uninjured fins for rate-limiting enzymes in the synthesis of serotonin tph1a, tph1b and tph2. Microscopic images near a bifurcation area (bifurcating bones highlighted with green dashed lines). tph1a and tph1b are not detected, while tph2 is expressed in a dotty pattern in the epidermis with a higher density between the bifurcating bones (E,E’,E”). N = 3 for each probe.