Fig. 6. Misexpression of Zic3 did not alter the expression of islet 1 or induce the expression of a ciliary margin marker, collagen IX. RCAS-Zic3 virus-infected retinas were analyzed at E7. Samples were double stained with an anti-viral GAG antibody (B,F) and an anti-islet 1 antibody (A), or an anti-collagen IX antibody 2C2 (C,E). (D) A bright-field image is shown. The same areas are shown in A and B, C and D, and E and F, respectively. Note that there was no apparent difference in either the number or distribution of islet 1-expressing cells in the infected area (A,B) compared with the uninfected wild-type area. Collagen IX is highly expressed in the very periphery of the retina, the prospective ciliary margin region (arrow in C), but not inside the retina, identical to the patterns in the uninjected control retina (not shown). Scale bar: 50 µm.