Figure 3.

The RA pathway is required for neuromast regeneration. A, Schematic representation of the experiment. Briefly, neuromast hair cell loss was induced by neomycin in 4.5-d-old non-dnRAR and dnRAR-expressing larvae, and heat-shocked to induce dnRAR-GFP expression. Hair cells were stained with DiAsp (red) at 4, 24, and 48 hpt to evaluate the regeneration progress. B–D, z-stack projection of neuromast stained with DiAsp in nonregenerating conditions. E–G, Neuromast with no DiAsp-labeled hair cells 4 h after neomycin treatment (E) and with newborn hair cells at 24 hpt and 48 hpt (F, G). H–J, Overexpression of dnRAR (shown in green) impairs hair cell regeneration at 24 hpt and 48 hpt, the effect being lower at 48 hpt when dnRAR is downregulated (I, J). K, Quantitative analysis of the number of hair cells at different time points in non-dnRAR and dnRAR-overexpressing larvae. **p < 0.01, ***p < 0.001. Scale bar: B, 10 μm.