Fig. 5. Genetic reduction of chordin, noggin and Nodal causes molecular laterality defects that are rescued by decreasing Bmp4 dosage. (A-K) Ventral views of 5s mouse embryos hybridized with Nodal probe. The node region is boxed. Arrowheads indicate Nodal expression in LPM. (A) Wild type, (B) Nodal^+/-, (C) Chrd^-/-, (D,E) Chrd^-/-;Nodal^+/-, (F) Chrd^-/-;Nog^+/-, (G,H) Chrd^-/-;Nog^+/-;Nodal^+/-, (I) Chrd^-/-;Nog^+/-;Bmp4^+/- and (J,K) Chrd^-/-;Nog^+/-;Nodal^+/-;Bmp4^+/-. At the bottom of each panel is a summary of the Nodal expression in the left LPM and the level of perinodal Nodal expression [normal (++) or weak (+)]. Orange indicates the presence of Nodal expression in left LPM, gray its absence.