Figure 4. Involvement of the JNK pathway in the transgression of the A/P boundary during regeneration.
(A–A′′) Wing disc and magnification showing activation of puc-LacZ (green) after ablation of the P compartment. The A/P boundary is outlined by Ci (red) label. Note that some anterior cells contain LacZ expression. The puc–lacZ staining is not particularly strong in the P compartment because it is located predominantly on the basal side of the disc, where the dying cells accumulate. (B and B′) Control non-ablated disc showing absence of puc-LacZ activity, except in the stalk region where it is normally expressed. The panel C illustrates the experiment designed to test the requirement for JNK activity for crossing the A/P boundary during regeneration. After removing repression by Gal80TS the dpp-LHG line forces hid activity in the dpp domain (red), located just anterior to the A/P line. At the same time the posterior compartment cells lose the potential to gain JNK activity due to puc over-expression. The results are illustrated in D–F′. Cells of posterior origin (green) can penetrate in the A compartment if they can activate JNK (E–E′′), but are unable to do so if JNK activation is prevented by puc over-expression. Quantitative data are shown in D. Bars represent S.E.M., n = 15 in each genotype, *p<0.05.