Fig. 2. Subdivision of the marginal retina characterized by expression of a combination of markers. The expression patterns of various molecular markers were examined by using adjacent sections of the marginal region of the E5 retina. The S-shape of the retina is the artifact produced during the fixation (see Fig. 1D). In these figures, the marginal region is towards the left and the central region is towards the right. (A,B,D-H) In situ hybridization or (C,I) immunohistochemistry of E5 adjacent sections stained for chicken Wnt2b (A), Pax6 (B), collagen type IX (C), Ptmb4 (D), LEF1 (E), Chx10 (F), Rx1 (G), Notch1 (H) and NF-M (I). The small arrowheads, arrows and large arrowheads indicate the retinal regions that presumably give rise to the iris/ciliary epithelium, the CMZ and the neural retina, respectively (shown at higher magnification in the righthand panels). For Wnt2b, the marginal tip of the retina is shown at higher magnification instead of the presumptive iris region. Note that the LEF1-expressing CMZ is characterized by weak expression of collagen type IX and Ptmb4; co-expression of Pax6, Chx10 and Rx1; and the absence of Notch1 and NF-M (J). Scale bars: 50 µm.