Fig. 1
Excess or lack of Grhl2 prevents PNP closure with differing PNP morphology at developmental stages from E8.5-9.5. a The PNP length of Axd/Axd and Axd/+ embryos was significantly enlarged compared with +/+ embryos (n = 215 embryos; 6–43 per genotype per stage; Supplementary Table 1). b The PNP length of Grhl2−/− embryos was enlarged from the 13–15 somite stage (E9.0) onwards, whereas Grhl2+/− embryos did not differ from wild types (n = 307 embryos; 4–55 per genotype per stage; Supplementary Table 1). ****p < 0.0001, ***p < 0.001, **p < 0.01, *p < 0.05 (ANOVA). c–f SEM of E9.5 embryos (18–19 somites) shows that PNP of Axd/Axd embryos is enlongated and very narrow compared with the PNP of wild-type embryos (d, f; arrows indicate rostral limit (closure point) of PNP). i–m The enlarged PNP of Grhl2−/− embryos is characterised by widely spaced neural folds at E9.5 (examples have 20–21 somites). Consequently, the angle between the open neural folds (shown in h) is significantly smaller in Axd/Axd (g) and greater in Grhl2−/− (n) embryos than in +/+ (*p < 0.05; n = 4–8 per genotype; Data represents mean ± SEM). Wild-type embryos did not differ between strains (g, n). Scale bars: 100 μm. Source data are provided as a Source Data file
