Fig. 8. Role of BMP signals on Nodal expression in the LPM. Asymmetric Shh in the left side of Hensen’s node induces the medial perinodal domain of Nodal expression. BMP endogenous signaling in the LPM induces Cfc expression making the cells competent to receive Nodal signaling. Nodal is presumed to diffuse from its medial domain of expression up to the area of competent cells where it activates its own expression. For details and references, see text.