Figure 5. NA inhibits CNC migration in Xenopus embryos by inducing Snail1 degradation.

(A–D) Xenopus embryos were injected in one blastomere at 2-cell stage with PBS (control; A), NA (70 ng; B), or NA combined with mRNA encoding GR-fused Snail1 (C). To induce nuclear translocation of Snail1, dexamethasone was added at stage 10–10.5 (C). Embryos were cultured to stage ~18 and processed for in situ hybridization for snail2. The injected side (on the right and denoted with an asterisk) was labeled with co-injected β-galatosidase (red), and arrows indicate the directions of migration of the three CNC streams. A representative embryo from each group is shown in (A–C), and quantitative results are summarized in (D). (E) Embryos were injected with mRNA encoding myc-tagged Snail1, and cultured with or without NA until stage 15–17 (shortly before CNC migration). Western blot was carried out with an anti-myc antibody for whole-embryo lysates or lysates of dissected CNC. Representative images of Western blots are shown in (E), and relative intensity of myc-tagged Snail1 normalized against β-actin was calculated and summarized in (F) (whole embryos) and (G) (CNC). *P < 0.05.