Fig. 6
Grhl2 dysregulation leads to abnormal surface ectoderm cell shape. a–c Dorsal SEM images of the spinal region (oriented with caudal to top) at the PNP closure point (indicated by asterisk) of wild-type, Grhl2−/− and Axd/Axd embryos at E9.5 (examples have 21 somites). d–f Magnified view of areas boxed in a–c, respectively. g, h Quantification of the length/width ratio of surface ectoderm cells located in the midline (based on major and minor axes as shown superimposed in inset image) and the lateral cells (remaining cells in the box) in Grhl2−/− and Axd/Axd mutants and corresponding wild-type controls. Wild-type embryos for both strains show significant change of length/width ratio between midline and lateral cells (**p < 0.01, *p < 0.05; t-test). Number of cells analysed = 19–102 per group; 3–5 embryos per genotype (see Supplementary Table 3). i, j Dimensions of cells in the midline. Data represent mean ± SEM (significant difference from wild type in equivalent region, **p < 0.01, *p < 0.05; t-test). k, l Cell outlines were segmented (using tissue analyser) from dorsal images of whole-mount ZO-1 immunostaining of the PNP region of Axd/Axd and +/+ embryos at E9.5. Scale bars: 50 μm. m, n Magnified view of boxed areas in k and l. o, p Circularity and angle from the rostro-caudal axis were determined for midline cells (orange in m, n) and lateral cells (remaining cells in box in m, n) for Axd/Axd and +/+ embryos (n = 3 per genotype; 22–27 midline cells and 260–332 lateral cells per genotype; significant difference from wild type, ***p < 0.001, *p < 0.05; t-test). Source data are provided as a Source Data file
