Fig. 4.

Hh, but not Wnt, signaling is disrupted in Sas4^−/− mutants. (A–D) Hh-dependent ventral cell types in the neural tube of E9.5 wild-type and Sas4^−/− p53^−/− embryos. In Sas4^−/− p53^−/− embryos floor plate cells (FOXA2, red) and V3 interneurons (NKX2.2, green) are absent (compare A and B), and PAX6⁺ interneurons (green) occupy the ventral neural tube (compare C and D). (E and F) The activity of the canonical Wnt reporter TOPGAL (blue) is normal in E8.5 Sas4^−/− mutants. (G–L) The PCP noncanonical Wnt signaling protein VANGL2 (green) localizes to the anterior/posterior (horizontal) faces of the cells in the embryonic node of both wild-type (G–I) and Sas4^−/− p53^−/− embryos (J–L) at E7.75. Rhodamine-conjugated phalloidin (red) marks F-actin at cell borders. (Scale bars: 300 µm in A–F, 3 µm in G–L.)