Fig. 1

The Zebrafish Wanderlust Mutant Has Hyperdendritic Melanophores due to a Loss of Bace2

(A) Brightfield imaging shows that the wanderlust melanophores are hyperdendritic compared with WT fish (arrowhead) in the tail fin at 72 hpf. Labeling of the melanophore cell membranes (bottom panel) using the Tg(tyrp1b: membrane-mCherry) line demonstrates that this is due to a change in cell morphology rather than a redistribution of melanin.

(B) These hyperdendritic melanophores are maintained into adulthood, and yield irregular stripe boundaries (arrowhead).

(C and D) wanderlust mutants develop melanophores outside of the stripe during metamorphosis at 24 days post fertilization (dpf) (arrowhead). Inter-stripe melanophores number are quantified in (D); fish number: n(WT) = 5, n(wanderlust) = 5, two-tailed t test, ^∗∗p < 0.01.

(E and F) Bace2 loss of function using morpholino knockdown (E) or pharmacological inhibition (F) phenocopies the wanderlust mutant. WT embryos are treated with Bace2 inhibitor (PF-06663195,100 μM) from 48 to 72 hpf.

(G) bace2^−/− melanophores have larger cell area in the tail fin at 72 hpf. Melanophore cell area is defined as the surface area covered by melanophores in the tailfin. Data are from five independent experiments, with total fish numbers: n(WT) = 80, n(bace2^−/−) = 105, two-tailed t test, ^∗∗∗∗p < 0.0001. All bar graphs are presented as means ± SEM. Scale bars: (A, B middle and bottom, C, E, and F) 100 μm; (B top) 0.5 cm.

See also Figure S1.