Apical disturbance of β-catenin expression and localization is accompanied by precocious differentiation of RPCs in Chx10Cre-RBPf/fretinae. (A-D) In wild-type retinae at E13.0 and E13.5, β-catenin expression is enriched along the apical surface of the retina (A, C). In the E13.0 RBP-J deficient retinae, however, expression is discontinuous (arrowhead in B), and the extents lacking β-catenin are enlarged at E13.5 (arrowheads in D). (E-H) Brn3+ ganglion cells are increased (arrowhead in F), but Sox2+ RPCs (arrowhead in H) are decreased in the gap region lacking β-catenin immunoreactivity in RBP-J deficient retinae at E13.0, as compared with wild-type controls (E, G). (I-P) Expression of Neurod1 is up-regulated (J), but that of Pax6 (L), Hes1 (N) and Hes5 (P) is not altered in RBP-J deficient retinae relative to wild-type controls at E12.5 (I, K, M, O). Scale bars, 100 μm.