Fig. 3.

Surface ectoderm tension is regionally heterogenous.

A) E9.5 mouse caudal region showing the different sites of SE ablation. Zone 1 = zippering point, Zone 2 = adjacent to the presomitic mesoderm, Zone 3 = adjacent to the somite region. Shaded yellow region = midline. Shaded red region = lateral. Cyan asterisk = ZP. Scale bar = 150 μm. B) Rostrocaudal recoil in Zone 1 is significantly lower than in Zone 2 (mean +/− SD, ANOVA, ** post-hoc Tukey's test, p < 0.008, n = 46 embryos). C) Midline cells in Zone 1 recoil significantly more than lateral cells (mean +/− SD, ** t-test, p < 0.008, n = 22 embryos).