Fig. 4.

Comparative expression analysis of Notch signaling components and FoxE3 in X. laevis embryos, showing that Notch2 and FoxE3 are expressed in PLE while Delta1 and Delta2 are expressed in presumptive retina. Expression of Notch2 (A–B'), Delta1 (C–E'), Delta2 (F–H'), and FoxE3 (I–K') was detected by in situ hybridization from neural plate stages to early tailbud stages. Regions circled with black broken lines in (C) and (F) are the approximate presumptive retina fields, where neither Delta1 nor Delta2 is expressed. Arrows in (B, B'), (D–E'), (G–H'), and (J–K') indicate expression of Notch2, Delta1, Delta2, and FoxE3, respectively. A black triangle in (C) indicates Delta1 expression in the anterior neural ridge, and white triangles in (A) and (I) indicate Notch2 and FoxE3 expression in the pre-placodal ectoderm, respectively. White lines in (E), (H) and (K) indicates the planes of transverse eye sections shown in (E'), (H') and (K').