Figure 2

Deletion of Ctnnb1 does not restore neurogenesis to Sox2- mutant cells. Transverse sections of E13.5 control and mutant eyes were analyzed for restoration of neurogenic fate to Sox2-ablated regions. (A, D, G, J) Ccnd1 mRNA localizes to the central optic cup (OC) of wild-type controls (A) and Ctnnb1^{lox(ex2–6)/lox(ex2–6)} single-mutants (D) and is maintained in the central OC of Sox2 single-mutants (G) and Sox2/Ctnnb1 double-mutants (J). (B, E, H, K) β-Tubulin III, marking neurons, is expressed in the retinal ganglion cell (RGC) layer of controls (B) and Ctnnb1 single-mutants (E), but its expression is markedly reduced in Sox2 single-mutant (H) and double-mutant (K) cells. (C, F, I, L) Sonic Hedgehog (Shh) mRNA expression correlates with the pattern of β-Tubulin III staining, and thus is significantly reduced in mutants (I, L) compared with controls (F, C). Black arrowheads in (C) and (F) indicate the limits of Shh expression. White arrowheads in (C, F, I and L) point to an unaffected region of Shh expression in the presumptive eyelid. Scale bars: 200 μm.