Fig. 4

Reduction of Med10 enhances Wnt signaling. (A–H) Reduction of Med10 results in expanded expression of Wnt target genes. MO1-Med10 (5 ng) was injected into embryos at the one-cell stage. Embryos were then fixed at either 30% epiboly (A–D) or 75% epiboly (E–H) and stained using in situ hybridization. Dorsal is right. Animal views are shown in (A–D); lateral views are shown in (E–H). eve1 expression was not affected by reduction in Med10 (A,B), serving as a control. Shown are spr2 expression in MO1-Med10 injected embryos (D,F) and control embryos (C,E); and cdx4 expression in MO1-Med10 injected embryos (H) and control embryos (G). (I–N) Reduction of Med10 leads to a graded expansion of lef1:gfp. Increasing amounts of MO1-Med10 were injected into embryos at the one-cell stage and in situ hybridization using a gfp riboprobe was performed on embryos at 30% (I–K) and 90% (L–N) epiboly. Animal pole views are shown in (I–K); lateral views are shown in (L–N). The region of gfp expression is increased in med10 morphants (J,K,M,N), as compared to control embryos (I,L). (O–Q) Reduction of Med10 enhances Wnt8-induced ectopic tail bud formation. wnt8/gfp mRNA (100 pg each) were injected into single cells at the animal pole of 128-cell stage embryos. Ectopic tail buds were induced in GFP-positive embryos (O), as confirmed by staining for tbx6 (P). Arrows indicate ectopic tail buds (O,P). (Q) Quantification of Wnt8-induced ectopic tail buds. Data presented in (Q) are the mean ± SD from at least three independent experiments. Total embryos scored were 663, 258, and 129 for wnt8/gfp, wnt8/gfp/MO1-Med10 (100 pg/100 pg/150 pg) and wnt8/gfp/med10 mRNA (100 pg each) injections, respectively.