Fig. 2. AP patterning of somites is disrupted in her1+7 MO-injected and b567 mutant embryos. WT denotes wild-type embryos, and MO denotes her1+7 MO-injected embryos. All panels are dorsal views with anterior towards the top. Developmental stages are indicated at the bottom right. The segmental expression of papc and myoD is disrupted throughout somitogenesis in MO-injected and b567 mutant embryos (A-H). The Notch ligands deltaD and deltaC are expressed throughout the presumptive somite rather than being restricted to the anterior or posterior half, respectively (I-L). Expression of a Notch receptor, notch5, is also disrupted (M,N). In addition, the expression of mespA is downregulated and not segmental in b567 mutant embryos (O,P). Both ephrin B2 (Q,R) and fak (S,T) are expressed throughout the paraxial mesoderm instead of in posterior half-somites.