Fig. 7. Correlation between the cnox-2+ cell number in head-regenerating sf-1 mutants and the regeneration phenotype. (A) Kinetics of head regeneration as assessed by TB emergence in wild-type hydra (black squares), sf-1 hydra maintained at 18°C (red diamonds) or 28°C (green circles). (B) Number of cnox-2⁺ apical cells in amputated sf-1 hydra maintained at 28°C and sorted according to their regeneration stage (n=22, 17, 16, 31, 14). (C-K) cnox-2 expression in amputated sf-1 hydra maintained at 28°C (C-H) or 18°C (I-K). (C) ball-shape stage-1; (D,I) elongated stage-2; (E,G,H,J) TB1 stage-3; (F) TB2 stage-4; (K) fully-regenerated stage-5. Endodermal staining is artefactual as samples were overstained. Scale bars: 100 µm.