Left/Right Determination Factor 2 (LEFTY2)

Lefty proteins are signaling ligands that act in opposition to the NODAL protein. During vertebrate development they regulate the degree of left-right asymmetry by controlling the spatiotemporal influence of the NODAL protein.It is involved in embryogenesis and left-right patterning. There are many differences between the left and right sides, including heart and lung positioning. Mutations in these genes cause incorrect positioning of these organs (e.g., situs inversus). Lefty1 in the ventral midline prevents the Cerebrus (paracrine factor or "Caronte") signal from passing to the right side of the embryo.The role of Lefty1 is to restrict the expression of Lefty2 and Nodal to the left side, and that Lefty2 or Nodal encode a signal for 'leftness.' Lefty2 serves as a feedback inhibitor to restrict the range of nodal signaling during establishment of the left-right axis.