Figure 4.

Expression of HNF-3β and Brachyury in E7.5 (A–D) and E8.5 (E–H) embryos. Adjacent sections of wild-type embryos (A, C, E, and G) and their mutant littermates (B, D, F, and H) were hybridized with HNF-3β (A, B, E, and F) and Brachyury (C, D, G, and H) antisense probes as described (16, 19). For all images, anterior is to the left, and posterior is to the right. Arrows in the mutants point to aberrant primitive streak, and horizontal lines show the presumptive embryonic–extraembryonic border. [Bar = 100 μm in A (also applies to C, E, and G) and 50 μm in B (also applies to D, F, and H).]