Fig. 2. Somites and retinoic acid inhibit Wnt8c expression. (A) Origin of explants used in B-C'. (B) Caudal neural plate (CNP) expresses Wnt8c (purple) after 24 hours culture whereas its counterpart explant pair (B') loses Wnt8c next to the quail somites (QCPN, orange). CNP explants in DMSO (control) (C) express Wnt8c after 24 hours, whereas 9cisRA represses Wnt8c (C'). Wnt8c expression in control (D) and VAD quails (E,F). Wnt8c is ectopically expressed in VAD neural tube. Arrowheads indicate the last somite formed; r4, prospective rhombomere 4; s6, somite 6 which indicates the level of the prospective hindbrain/spinal cord boundary. (G) Origin of explants derived from VAD quails used in (H,H'). VAD neural tube (VAD NT) explants still express Wnt8c after 6 hours in DMSO (H), but this is lost with SU5402 (H'). r4, prospective rhombomere 4; s6, somite 6. Scale bars: 50 µm in B for B-C'; 100 µm in D for D-F; 25 µm in G for H,H'.