Figure 3

The number of cells expressing Zic2 and Islet1/2 in the pigmented and albino ventrotemporal retina does not differ at embryonic day 17.5. (A) Fluorescent sections through ventrotemporal (VT) retina stained with antibodies to Zic2 and Islet1/2 at embryonic day (E)17.5. Methodology of quantification in (B) and (C) is similar to the methods used in Figure 2, but representative sections are the second and fourth sections anterior to the optic nerve. (B) At E17.5, the number of Zic2⁺ cells is not significantly different in albino (n = 7) compared with pigmented (n = 7) retina in every sector. (C) The number of Islet1/2⁺ cells is also similar in the pigmented (n = 7) and albino (n = 7) retina at E17.5 across sectors. Distance from periphery: 1 pixel = 0.3205 μm. (D) Summary scheme of Figure 2 and Figure 3. At E15.5, the number of Zic2⁺ RGCs is reduced in the pigmented and albino, consequently diminishing the total RGC population. The number of Zic2⁻ RGCs is unchanged. At E17.5, the numbers of Zic2⁺ RGCs and Zic2⁻ RGCs are similar in pigmented and albino. Thus, the total number of RGCs is similar. Error bars indicate SEM. Two-tailed unpaired t-test: *P < 0.05. N.S., not significant. Scale bar in (A), 100 μm.