Figure 5

A similar number of Zic2⁺retinal ganglion cells are born in the pigmented and albino ventrotemporal retina at embryonic day 14. (A) Timeline of 5-ethynyl-2’-deoxyuridine (EdU) injections (10 am, 2 pm, 6 pm) at embryonic day (E)14 and sacrifice at E15.5. Each box represents 4 hours. All quantifications for (B-D) were carried out in two alternating representative sections caudal to the optic nerve. Ventrotemporal (VT) region defined as most peripheral 800 pixels (1 pixel = 0.3205 μm). (B) Bar graph comparing the number of Zic2⁺ retinal ganglion cells (RGCs) in the VT region labeled with EdU in pigmented (n = 5) and albino (n = 5) retina. An equal number of Zic2⁺/Islet1/2⁺ cells become post-mitotic at E14.5 in albino VT retina compared with pigmented VT retina. (C) Bar graph comparing the number of Zic2⁻/Islet1/2⁺ cells in VT retina labeled with EdU in pigmented (n = 5) and albino (n = 5) retina. As in B, the number of Zic2⁻ RGCs at E15.5 that were born at E14 is similar in pigmented (n = 5) and albino (n = 5) retinae. (D) The number of total Islet1/2⁺ cells in VT retina labeled with EdU is also similar in pigmented and albino retinae. Error bars indicate SEM. Two-tailed unpaired t-test. N.S., not significant.