Fig. 6

RA and Fgf signals are involved in the formation of the duplicated neural structure in embryos lacking Cdx1a/4. (A-U) Expression of krox20 (A-D,U), hoxb1a (E-H), valentino (I-L), hoxb4a (M-P) or hoxb5a (Q-T) in embryos that received an injection of cdx1a/4MOs and 2 ng each of the fgf3MO and fgf8MOs (A,E,I,M,Q) or injection of cdx1a/4MOs and 2 ng each of wnt3aMO and wnt8MOs (U); cdx1a/4 morphant embryos that were treated with 300 µmol/l SU5402 (B,F,J,N,R); cdx1a/4 morphant embryos that were treated with 50 μmol/l DEAB (C,G,K,O,S); cdx1a/4 morphant embryos that were treated with 300 μmol/l SU5402 and 50 μmol/l DEAB (D,H,L,P,T) at 22 hpf. (V-X) Expression of krox20 (V), hoxb1a (W) and valentino (X) in cdx1a/4 morphant embryos that were treated with 100 μg/ml recombinant mouse FGF8b. The ectopic expression is marked by arrowheads. Scale bar: 100 μm.