Fig. 4. Shh and Ptc1 expression in E11 eyes. (A1-B3) Developing retina (de) at E11. (C1-D3) Retina regenerating from the CB/CMZ (cr). (E1-E3) Transdifferentiating retina (td) at E11. (A1) Expression of Shh mRNA during normal development is predominantly in the ganglion cells of the posterior retina. (A2) Shh protein expression in the posterior retina of the developing eye mirrors that of the mRNA expression. (A3) Ptc1 expression in the posterior retina of a developing eye is located through the INL and ONL. (B1) Shh mRNA expression in the anterior part of the developing eye includes the presumptive CMZ. (B2) Shh protein expression is similar to that of the mRNA expression. (B3) Expression of Ptc1 mRNA is in the anterior retina and ciliary region. (C1,D1) During CB/CMZ regeneration, Shh expression patterns basically remained unchanged, however the levels in the posterior region were low (arrowhead in C1). (C2,D2) Shh protein expression of retina regenerating from the CB/CMZ. (C3,D3). Ptc1 expression is present throughout part of the INL and ONL in the posterior (arrowhead in C3) as well as anterior part (arrowhead in D3) of the CB/CMZ regenerated retina. (E1) Transdifferentiating retina shows Shh mRNA expression in the ganglion cell layer (arrowhead). (E2) Shh protein expression is diffused through out the transdifferentiating retina but the expression is mainly in the ganglion cell layer (arrowhead). (E3) Ptc1 expression is predominantly in the INL of the transdifferentiated retina (arrowhead). F1, F2 and F3 are negative controls for Shh RNA, Shh Protein and Ptc1 RNA expression respectively. Arrowheads mark areas of expression.