Embryonic requirement for ErbB signaling in pigment pattern metamorphosis. (A) Control wild-type zebrafish treated from embryonic through juvenile stages with DMSO alone. (B) Wild-type treated with AG1478 during embryonic stages (70% epiboly - 4 dpf) showed adult pigment patterns resembling severely affected picasso mutants (arrow). (C,D) Individuals treated with AG1478 during the pre-metamorphic, early larval period (5-14 dpf, C) or throughout metamorphosis (15-28 dpf, D) exhibited pigment patterns indistinguishable from controls. (E) Metamorphic melanophore densities in the mid-trunk (mean±95% confidence intervals) showing similarities between wild-type (untreated), control (con, DMSO-treated) and fish treated with AG1478 during pre-metamorphosis (pre) and metamorphosis (met), as well as similar defects between picasso mutants (pcs) and fish treated with AG1478 as embryos (emb). Letters above bars indicate means that are not significantly different (P>0.05). Numbers within bars are samples sizes. (F,G) D. albolineatus normally develop a more uniform melanophore pattern of metamorphic melanophores (arrowheads in F) compared with D. rerio, and exhibited a severe melanophore deficiency when embryos were treated with AG1478 (G). (H,I) In D. nigrofasciatus, adult stripes largely comprise persisting embryonic/early larval melanophores with occasional gaps (arrow in H), and embryonic treatment with AG1478 had relatively subtle effects (arrows in I). (J,K) Embryonic morpholino knockdown of erbb3b resulted in adult melanophore deficiencies (K) compared with controls (J), providing independent evidence for an early erbb3b-dependence of adult pigment pattern formation. Scale bar: in I, 0.5 mm for A-D,F-I,J,K.
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