FIGURE 4:

ADAM19 is expressed in the relevant spatiotemporal pattern to cleave Cad6B in vivo. (A, C, E, G, I, K, M) Whole-mount in situ hybridization for ADAM19 using an ADAM19 antisense riboprobe, followed by indicated transverse sections (B, D, F, H, J, L, N) through the chick midbrain. Arrowheads and arrows indicate expression in premigratory and migratory neural crest cells, respectively. ADAM19 is noted as early as the 3ss (A) in the dorsal neural folds (B) and later on in the dorsalmost region of the neural folds as neural fold fusion is occurring (C–H). At the onset of EMT and neural crest cell migration, ADAM19 is expressed by migratory neural crest cells and is absent in the dorsal neural tube (I–N). ADAM19 is also present at low levels in the mesoderm, ectoderm, and neural tube. ADAM19 sense probe (O, P) shows no signal and serves as a negative control. Scale bar, 250 μm (A) and 50 μm (B), all whole-mount and section images, respectively.