Movie 4.

Characterization of mechanical strain around the future foot region in a regenerating tissue spheroid. Time-lapse, spinning-disk confocal movie of a regenerating tissue fragment expressing Lifeact-GFP in the ectoderm (Fig. 3H). The tissue spheroid was oriented with its future foot region facing the objective, showing the focus region that develops into a pair of +1/2 defects at the future foot region (cyan labels). The images show computationally generated projected views of the fiber organization at the ectodermal basal surface (upper left), the cellular organization at the ectodermal apical surface (upper right), and cell segmentation maps depicting ectodermal cells colored according to their area (lower left; Range (white to red): 300-1200 μm²) or cell anisotropy (lower right; Range (white to red): Q=0.1-0.65). The nematic orientation of the fibers in each cell is overlaid on the segmentation maps. The images were centered to correct for movements of the whole tissue. The elapsed time from excision is displayed (hh:mm), and the scale bar is 100 μm.