Fig. 5

Disruption of gene function by knocking-in pax7a and sox5. (a-e, h-i) Progenies (9 dpf) of a pax7a-transgenic founder crossed to an existing pax7a mutant, leucophore free 2 (lf-2, f-g). (j-n, q-r) Progenies (9 dpf) of a sox5-transgenic founder crossed to an existing sox mutant, many leucophores 3 (ml-3, o-p). (a, h, i, j, q, r) GFP. (b, d, f, k, m, o) Leucophores viewed in reflected light. (c, e, g, l, n, p) Xanthophores viewed in transmitted light. (b, d, f, k, m, o) Dorsal views of the trunk. (c, e, g, h, i, l, n, p, q, r) Lateral views of the trunk. (h–i, q–r) Confocal microscopy of the body surface of the nine dpf progenies. (a, j) Lateral views of pax7a-transgenic fish (a) and sox5-transgenic fish (j). A non-GFP (upper) and a GFP-positive (lower) larva are shown. Whereas the non-GFP larva (pax7a ^+/lf-2 ) has leucophores in the dorsal midline (b, white arrow) and shows yellow pigmentation in the skin (c, arrowhead), presumably having xanthophores developing normally, the GFP-positive knock-in larva (pax7a ^GFP/lf-2 ) fails to have leucophores (d, grey arrow) or show yellow pigmentation (e, open arrowhead). An lf-2 larva shows the pax7a loss-of-function phenotypes (f, g). Whether having a pax7a knock-in GFP allele with a wild-type allele (h, heterozygote) or with an lf-2 allele (i, homozygote), the larva has GFP/pax7a-positive progenitors on the surface of the trunk. As shown in B and C, the non-GFP offspring obtained from the sox5-transgenic founder shows normal pigmentation (k, white arrow; l, arrowhead). The GFP-positive larva has excess leucophores bilaterally along the dorsal midline (m, arrows) and lacks yellow pigmentation (n, open arrowhead), as does the ml-3 mutant (o, p). While sox5 heterozygous larva (q, sox5 ^GFP/+ ) has GFP-positive presumable xanthophore progenitors on the surface of the trunk, sox5 homozygote (r, sox5 ^GFP/ml-3 ) lacks GFP-positive cells in the corresponding area