Fig. 5. Induction of Nodal and Lefty1 by a Nodal expression vector. Expression vectors for Nodal plus EGFP (enhanced green fluorescent protein) (A-H) or those for caALK4 plus EGFP (I,J) were introduced by electroporation into the anterior region of right LPM of a wild-type (WT) embryo (A-E,I) or into the anterior region of left LPM of a Foxh1^c/- embryo (F-H,J). Electroporated expression vectors are shown in blue, while genotypes of the recipient embryos are shown in red. Six hours after electroporation, expression of Nodal (N in B,C,F) or Nodal plus Lefty1 (N+L1 in D,E,G-J) was examined by whole-mount in situ hybridization. Electroporated regions, which were confirmed by the presence of EGFP fluorescence (A), are indicated by the square brackets. Anterior views are shown in (A,B,D,F-J), whereas right lateral view is shown in C. A transverse section at the plane indicated in D is shown in E. A magnified view of the boxed region indicated in G is shown in H. Arrowheads indicate Nodal expression in the right LPM (C) and Lefty1 expression (E,H) induced by the Nodal expression vector.