Fig. 3.

Frizzled1/2/7 is required for endoderm specification. In situ distribution of mRNA encoding germ layer markers in control and DnFz7-injected embryos. (A) Four endoderm specification genes, including Brachyury, which is expressed both in the vegetal plate and the oral ectoderm. (B) Two ectoderm markers staining, respectively, the oral (Nodal) and aboral (Coquillette-Tbx2/3) ectoderm. (C) Two skeletogenic mesoderm markers. (D) Five distinct non-skeletogenic mesoderm markers that either label all (Delta, Nlk, Papss) or a subset (GataC, Gcm) of the non-skeletogenic mesoderm cells. Expression patterns of all genes are shown in control and DnFz7 embryos, as indicated. All embryos are in lateral view unless otherwise indicated as ‘vv’ for vegetal view. All embryos are at the mesenchyme blastula stage, except the Wnt8 section (analyzed also at the 60-cell stage in C), and FoxA, Papss and Gcm sections [shown also at 24 hpf (gastrula stage)].