Fig. 2. Necab co-expresses with Pax6 in the developing optic vesicles and in the pre-tectum. (A-D) Whole-mount in situ hybridization showing Necab expression in the optic sulcus, optic vesicles (black arrowhead) and pretectum (white arrowhead). (C,D) Frontal and top views of the embryo, respectively, showing the sharp expression domain of Necab in the pretectum. (E) Necab mimics Pax6 expression pattern in the embryonic forebrain. (F) Necab expression is detected in the midbrain at 10.5 dpc, in contrast to Pax6. The arrowhead shows the forebrain/midbrain boundary. (G-J) Necab is expressed in a gradient manner in the optic vesicle (cross sections). Strong expression is observed in the presumptive ciliary margin region (G), similar to Pax6 (H). By contrast, (I) Rx expression is predominant in the retinal plate (RP) and (J) Lhx2 expression is predominant in the inner portion of the optic vesicle (arrowheads). (K) Necab expression is detected in the retinal-pigmented epithelium (rpe) and is predominant in the ciliary margin (cm) of the neural retina (nr), like Pax6. (L). fb, forebrain; hb, hindbrain; lp, lens placodes; ls, lens; mb, midbrain; ov, optic vesicle; prt, pre-tectum; rp, roof plate of the midbrain.