Fig. 6. Dynamic expression pattern of Nodal. (A,B) Ventral (A) and posterior (B) views of mouse embryos. (A) Nodal expression begins in the node at E7.5 and (B) develops asymmetrically a few hours later (four-somite stage) in the lateral plate mesoderm (LPM). (C-E) Lateral views of mouse embryos. (C) Nodal expression in the left LPM begins in a small region at the level of the node (purple arrow) at the two- to three-somite (s) stage at E8.0. (D) It then expands rapidly within the left LPM along the AP axis (red arrows indicate the expansion of Nodal expression), and (E) disappears by the seven-somite stage (red arrow indicates). Figure courtesy of Chikara Meno (Kyushu University, Japan).