Dpp signalling in discs under ablation.

<p>(A–C″) Triple staining for <i>dpp</i> transcription and Caspase 3 and GFP activities in control <i>UAS-GFP/tub-Gal80^TS; rn-Gal4</i> (A–A″) discs and in <i>UAS-hid tub-Gal80^TS; rn-Gal4/</i>discs at the end of a 48 hrs period of ablation time. The B–B″ and C–C″ panels show the apical and basal regions of the experimental discs. Note that in the latter <i>dpp</i> transcription appears normal (B–C″) and similar to that in controls. Apoptotic cells, marked by the high levels of Caspase 3, accumulate in the basal region (C′) of the disc. (D–D′) Experimental disc stained for TUNEL and pMad activity at the end of the 48 hrs of ablation. The panel D shows the merge of channels in the basal plane of ablating disc. (D′) Elevated levels of pMad were associated with apoptotic cells at the basal plane of ablated disc. (E) pMAD expression in a control disc. (F–F′) Optomoter blind (Omb) expression at the end of the ablation period. Panel F show the merge of channels of triple staining (GFP, red for TUNEL and blue for Omb) in the apical plane of the disc. In the single channel (F′) Omb is shown in white for better visibility. Omb levels are practically normal in the apical plane (F′), where the expression is very similar to that of control discs (G). (H–H′) Spalt (Sal) expression at the end of the ablation period. Panel H shows the merge of channels in the apical planes of the disc under ablation. The levels of Sal (white) are close to normal in the apical plane of ablated disc (H′) and similar to that of a control disc (I).