Fig. 2

Zebrafish wwtr1 mRNA expression. WISH data from 8-cell stage to 96 hpf. Wwtr1 mRNA is maternally provided (A) and then ubiquitously distributed at low levels during gastrulation (B) and early somitogenesis (C), when a strong signal is detected in dorsal forebrain (D), hindbrain (E) and adaxial cells (F). Diffuse expression at 24 hpf, with strong expression in brain (G), eye (lens and retina) (H), otic vesicles (I) and lateral line primordium (J). At 42 and 48 hpf, wwtr1 mRNA is seen in lens, pectoral fins and pharyngeal area (K–N). Transverse section of a 60 hpf embryo showing a large domain of wwtr1 mRNA-positive cells covering the pharyngeal tissue and the thyroid follicle with TG immunostaining depicted (N). At 96 hpf, wwtr1 is expressed in pectoral fins (P), liver and gut (Q), anterior craniofacial (R) and neurocranial (S) cartilages. Arrowheads indicate higher level of expression in the pectoral fin mesenchyme proximally (O and P) Scale bar = 200 µm. 3–7, (branchial) aortic arch arteries; df, dorsal forebrain, ac, adaxial cells; cp, cephalic floor plate; di, diencephalon; ep, ethmoid plate; ey, eye; fm, fin mesenchyme; ff, fin fold; gt, gut; hb, hindbrain; le, lens; l, liver; lp, lateral line primordium; m, mouth; mb, midbrain-hindbrain boundary; n, notochord; ov, otic vesicle; pc, polar cartilage; pf, pectoral fin; ph, pharyngeal tissue; te, telencephalon; tl, thyroid follicle lumen; tf, thyroid follicular cells; tp, thyroid primordium; tr, trabeculae. Anterior is to the left in dorsal (A, D–F), ventral (R and S) and lateral view (B, C, G–L, Q). In (M), anterior is to the top in dorsal view.