Fig. 1

Large wounds induce hyperpigmentation in both zebrafish larvae and adults. (A) Schematics showing the wounding procedures used in this study. In zebrafish larvae, a small wound was made using a tungsten needle and then a bead was implanted through this wound into the muscle beneath the skin. In adults, a full thickness incisional wound through all skin layers was made on the fish flank using a scalpel. (B) A small needle wound to larval flank does not lead to melanocyte recruitment (Bi), whereas a wound resulting from the implantation of a bead (white asterisk) recruited melanocytes by 24 hpi (Bii). A large larval fin wound generally draws melanocytes to the site of tissue damage by 9 hours after wounding (Biii; red dashed line highlights the wound site). (C-F) Snapshot images showing time-course of progressive wound hyperpigmentation around an implanted bead in a zebrafish larva. (G-I) Still images, taken from supplementary material Movie 1, indicating the dynamic behaviour of melanocytes around the bead at 24 hpi after engraftment in a zebrafish larva. The same position is indicated by a white asterisk in sequential images to aid visualisation of a single melanocyte as it envelops the bead. (J-L) Time-course showing adult wound hyperpigmentation over a duration of 34 days post-wounding (DPW). Insets indicate how hyperpigmentation spreads into adult non-stripe domains. Scale bars: 50 μm (B); 100 μm (C-F); 25 μm (G-I); 500 μm (J-L); and 250 μm (J-L insets).