Fig. 8. Comparison of Pax2 immunolocalization during and after optic fissure closure in WT versus Fz5^-/- retinas. In A-L, pairs of nearby sections are shown in order to better illustrate the staining and visualize the three-dimensional anatomy. (A-D) Anti-Pax2 immunostaining at E13.5 showing the posterior expansion of the domain of Pax2 expression in the Fz5^-/- optic fissure. Arrowheads indicate the posterior border of the optic fissure and the zone of Pax2 expression that tracks the optic fissure. (E-H) At E14.5, when Pax2 is no longer detected in the ventral retina in the WT mouse, it continues to mark the ventral fissure in the Fz5^-/- retina. A-H are sectioned in the horizontal plane; nasal is upward, as indicated in A (N, nasal; T, temporal). (I-L) At E14.5, Pax2 abundance in the optic disc and optic nerve is similar in WT and Fz5^-/- retinas. (M,N) Whole-mount immunostaining at E16.5 showing Pax2 in the ventral fissure region of the Fz5^-/- retina. Insets show a plane of focus within the optic disc, showing a ring of Pax2-positive cells around the optic nerve. (O,P) The number and lateral distribution of Pax2-expressing astrocyte precursors at the vitreal face of the retina are increased in the Fz5^-/- eye.