Fig. 3

Fig. 3 Expression of vlgr1 during wild type zebrafish development. (A–E,G,I,J) Expression of vlgr1 in the central nervous system. (A) vlgr1 is strongly expressed at 24 hours post fertilization (hpf) in the forebrain, at the telencephalic–diencephalic boundary and in the diencephalon; vlgr1 expression is detected in the midbrain, and expression in the hindbrain colocalizes with that of atonal homolog 1a (atoh1a)(A′), thus identifying these domains as the upper (arrowhead) and lower rhombic lips (arrow) (Koster and Fraser, 2001). (B,C) At 26 hpf vlgr1 is expressed in the hypothalamus (white arrow) and in the ventral epiphysis; compare with islet1 (isl-1) expression in the epiphysis (Korzh et al., 1993) in (B′). Elongated arrow in (B) indicates the level of the transverse section showed in (C). Dark coloration surrounding the retina (C) stems from the retinal pigmented epithelium. (D) At 48 hpf, expression is detected in the lower rhombic lip (arrowheads) in a transverse section at the level of the otic vesicle. (E) Expression at the telencephalic–diencephalic boundary (white arrowhead), in the lower rhombic lip (arrow) and in a small patch of cells (black arrowhead) in the dorsal tegmentum; comparison with atoh1a expression confirms their location rostral to the cerebellum (brackets in E–H) and demonstrates colocalization of vlgr1 and atoh1a in the lower rhombic lip (arrow). Elongated arrow in (E) indicates transverse section at the level of the otic vesicles in (D). (G) Expression at 72 hpf in the lower rhombic lip (arrow) and in the cerebellar commissure (white arrowheads). (H) pax2a expression at the same developmental stage is located to the mid-hindbrain boundary (bracket)(Thisse et al., 2001). (I,J) vlgr1 transcript in the developing retina at 48 hpf (I) and 72 hpf (J); expression is first detected as weak expression in the choroid fissure (arrow in I), and at 72 hpf (J) is associated with the optic nerve (arrowheads). (K,L) Transverse sections at the level of somite 10 at 72 hpf, showing vlgr1 expression in the pronephric duct (arrows); compare with pronephric pax2a expression in (L); the red coloration observed is due to red blood cells in the dorsal aorta (a) and axial vein. (C,D,K,L) transverse sections; (A,B,E,F,I) lateral views; (G,H) dorsal view; (J) ventral view. Abbreviations: d, diencephalon; e, epiphysis; g, gut; hb, hindbrain; hy, hypothalamus; l, lens; n, notochord; ov, otic vesicle; t, telencephalon.