Notch inhibition results in excess regenerated hair cells. A, Graph of HC regeneration after 400 μm neomycin (Neo) exposure as seen with FM1–43FX in larvae with 50 μm DAPT incubation, a Notch inhibitor, or 0.5% DMSO vehicle control. Results are graphed as mean percentages of HCs (±1 SEM) normalized to the control at 5 dpf (n = 8 fish per condition; 6 neuromasts per fish). B–E, Confocal maximum projections of representative neuromasts under continuous BrdU incorporation for 48 h, with and without 50 μm DAPT. Hair cells were labeled with myosin-VI (green), and BrdU-labeled cells are red. Scale bar, 10 μm. F, Stacked graph of average myosin-VI-labeled HCs per neuromast either colabeled with BrdU (red) or are BrdU-negative (green). Excess HCs with 50 μm DAPT incubation all contained the BrdU label, indicating mitotic origin. Error bars represent ±1 SEM (n = 4 fish per condition; 3 neuromasts per fish).