Generating asymmetries in the early vertebrate embryo: the role of the Cerberus-like family.

One fundamental aspect of vertebrate embryonic development is the formation of the body plan. For this process, asymmetries have to be generated during early stages of development along the three main body axes: Anterior-Posterior, Dorso-Ventral and Left-Right. We have been studying the role of a novel class of molecules, the Cerberus/Dan gene family.

Cripto-independent Nodal signaling promotes positioning of the A-P axis in the early mouse embryo.

During early mouse development, the TGFbeta-related protein Nodal specifies the organizing centers that control the formation of the anterior-posterior (A-P) axis. EGF-CFC proteins are important components of the Nodal signaling pathway, most likely by acting as Nodal coreceptors. However, the extent to which Nodal activity depends on EGF-CFC proteins is still debated.

The activity of the Nodal antagonist Cerl-2 in the mouse node is required for correct L/R body axis.

Correct establishment of the left/right (L/R) body asymmetry in the mouse embryo requires asymmetric activation of the evolutionarily conserved Nodal signaling cascade in the left lateral plate mesoderm (L-LPM). Furthermore, the presence of Nodal in the node is essential for its own expression in the L-LPM. Here, we have characterized the function of cerl-2, a novel Nodal antagonist, which displays a unique asymmetric expression on the right side of the mouse node.