BMP inhibition by DAN in Hensen's node is a critical step for the establishment of left-right asymmetry in the chick embryo

► Dan is expressed in the left side of the node. ► DAN inhibits BMP signaling but not NODAL signaling. ► Dan is indispensable for Nodal in the LPM and for Lefty-1 in the notochord. ► Nodal up-regulation by DAN requires NODAL signaling. ► DAN might act synergistically with NODAL to induce Nodal and Lefty-1.