Fig. 7. Pax7EnR promotes satellite cell apoptosis during tail regeneration. (A-C) TUNEL assays were performed on parasagittal sections of regenerated tail at 3 dpa; the colour was developed with a Fast Red tablet and counterstained with Mayor's Hematoxylin. (A) Wild-type regenerated tail. (B) Heat-shocked pax7EnR transgenic regenerated tail. (C) Higher power view of B. TUNEL signals in the blastema region are arrowed. (A-C) Dorsal side upwards, anterior towards left. (D) Detection of Pax7 with DAB staining (left panel) and apoptosis with fluorescein labelling (middle panel), in a cluster of cells in pax7EnR transgenic tail. The right panel is the merged view. Red arrows: two TUNEL-positve/Pax7 low expression cells. (E) Quantification of the number of apoptotic cells in the two groups of tails. (F,G) Detection of MyoD (red) and cell death (green) on parasagittal sections of regenerated tails at 3 dpa. (F) Blastema region of wild-type tail. (G) Blastema region of heat-shocked pax7EnR tails. (H) Quantification of the percentage of apoptotic cells among the MyoD-positive cells in the two groups of tails. Ten tails of similar size were examined in each group. ^**P<0.01. Abbreviations: S.C., spinal cord; Not., notochord; Mes., mesenchyme; Blt., blastema. Scale bars: 100 µm.