Fig. 6

julie^j24e1 Mutation Disrupts Melanocyte Regeneration prior to the dct⁺ Stage and Blocks Tail Regeneration Following Amputation (A and B) Larval melanocytes in julie^j24e1 and wild-type larvae were ablated by MoTP treatment from 14 to 72 hpf, and melanocyte regeneration was analyzed at 5 dpf by ISH with dct riboprobes for late-stage melanoblasts. At this stage, many dct⁺ melanoblasts (melanin^-, blue arrow in [A]) and melanocytes (melanin⁺, black arrow in [A]) appear in wild-type larvae (A). While few melanocytes (melanin⁺, black arrow in [B]) appear in the julie^j24e1 larvae, no dct⁺ melanoblast was detected by ISH (B). (C–F) julie^j24e1 mutants fail to regenerate larval tails following amputation. Larval tails were amputated at 60 hpf (C and D) and tail regeneration in wild-type and julie^j24e1 larvae were examined at 5.5 dpf (E and F). At this stage, wild-type larval tails (E) were mostly reconstituted, including fin-fold tissues (outlined with white-dashed line) and melanocytes (arrow in [E]). In the julie^j24e1 larvae, the amputation wound healed but the julie^j24e1 mutant tail failed to regenerate (F). Arrowheads indicate the amputation planes in (C–F). The white-dashed lines outline the fin folds. Timeline (grey) above (A) indicates the period of MoTP treatment (red) and analysis time (vertical line below the timeline). Scale bars: 250 μm.