Figure 4. RT–PCR analysis of Hedgehog signaling pathway genes in wounded and unwounded wild-type and Pax6^+/− corneas. RT–PCRs (primers and conditions as described in the Methods section and Table 1) were performed on pooled samples of wounded and unwounded wild-type and Pax6^+/− corneas (4 corneas from different mice pooled for each condition). Wild-type and Pax6^+/− corneas are represented as ‘+/+’ and ‘+/−’ respectively. Negative controls were PCRs on corneal samples without reverse transcriptase but otherwise treated as the other samples. Positive control was RT–PCR from preparations of embryonic neural tube and surrounding dorsal structures including the notochord. Multiple signaling pathway components were detected. The only difference between wounded and unwounded corneas was the upregulation of Shh. The only difference between wild-type and Pax6^+/− was the upregulation of Gli1.