tfec is a marker of differentiated iridophores, but not xanthophores.
(A–D) Chromogenic whole-mount in situ hybridisation reveals tfec expression in iridophores at 3 dpf. Iridophores (asterisks) of the posterior trunk/anterior tail are imaged live with reflected light in lateral (A) and dorsal (B) views. (C,D) Whole-mount in situ hybridisation on the same embryo reveals a pattern of tfec expression matching that of the differentiated iridophores (asterisks). The colour of the asterisks indicates corresponding iridophore patches between A and C, and B and D. Note the absence of expression in the location of the associated melanocytes (residual melanin indicated by arrowheads) (E-G). Expression of tfec (E, in situ hybridisation) and of Pax7 (F, immunofluorescence) in differentiated iridophores and xanthophores, respectively, at 48 hpf; note the absence of co-expression of these markers. A,C,E: lateral views; B,D: dorsal views. Head towards the left. Scale bars: A-D, 50 μm; E-G, 20 μm.