Figure 5.
smad2ΔC/ΔC mutants do not make mesoderm. Whole mount in situ hybridization against markers of embryonic lineages. (A) T in E7.5 embryos. The primitive streak (ps) can be found in the normal embryo (Left) but not in the mutant embryo (Right). epc, ectoplacental cone. (B) bmp4 in E7.5 embryos. The arrow points to the allantois of the normal embryo (Left), whereas the chorion and amnion are less visible. The three mutant embryos shown on the Right fail to exhibit staining for this marker. (C) fgf8 in E7.5 embryos. The primitive streak (arrowhead) is stained in the normal embryo (Left). Note the lack of staining in the two mutant embryos on the Right. (Bar = 458 μm for A and C and 523 μm for B.)