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Fig. 6
TP-0903 inhibits expression of dlx2a and induces expression of mitfa in the presumptive ectomesenchymal NC cells. Dorsal views of embryos treated with DMSO or TP-0903 at the 3-somite stage and fixed at the indicated time points for processing by whole-mount in situ hybridization and brightfield microscopy with the indicated probes or direct visualization of pigment cells. (A) Compared to controls (top panel), TP-0903 completely inhibits dlx2a expression in cranial NC streams (18/20 embryos). (B) Analysis of TP-0903-treated embryos with the pan-NC marker crestin shows that NC cells that normally express dlx2a lateral to the neural tube are induced but fail to migrate away, and the first two cranial NC streams are fused together, as indicated by numbered asterisks (13/18 embryos). (C) Analysis of melanophore precursor marker mitfa in control and TP-0903-treated embryos show that TP-0903 induces aberrant mitfa expression in the NC cells lateral to the neural tube (18/20 embryos) (black arrows). (D) Analysis of differentiated melanophores at 48hpf shows that TP-0903 causes accumulation of melanophores on the dorsal neural tube (arrows), but not adjacent to the neural tube (18/21 embryos).