Figure 5

Sfrp1 _NTR rescues the phenotype induced by Wnt8 over-expression. All the panels are dorsal (a-d; i-k) or lateral (e-h; l-n) views of embryos at stage 19–20 injected with GFP mRNA (a,e); GFP together with Wnt8 (b,f), Sfrp1 _CRD (c,g), Sfrp1 _NTR (d,h) or Wnt8 together with Sfrp1 (i,l), Sfrp1 _CRD (j,m) or Sfrp1 _NTR (k,n) mRNA as indicated. Optic vesicles fail to develop in embryos injected with Wnt8 mRNA, as judged by the reduction in rx3 expression (b,f). (i-n) This defect is reverted by Sfrp1 (i,l) and Sfrp1 _NTR (k,n) but not by Sfrp1 _CRD (j,m) co-expression. Note that Wnt8-induced forebrain reduction is somewhat enhanced in the presence of Sfrp1 _CRD . Embryos were processed for double in situ hybridization with rx3 (red) and foxA2 (blue) probes. Arrows and arrowheads (i,l) indicate moderate expansion of anterior tissue and axial duplications induced by Sfrp1 over-expression. See Tables 1 and 2 for details. Scale bar: 0.18 mm (a-d,i-k); 0.25 mm (e-h;l-m).