The evolutionary origin of hedgehog proteins.

摘要: Summary Animal development is orchestrated largely by diffusible ligands of the Wnt, TGF- β , hedgehog (Hh) and FGF signaling pathways, as well cell-surface molecules, such Notch, cadherins, integrins immunoglobulin-like proteins [1,2]. Here, we show that Hh are likely to have evolved very early in metazoan evolution domain shuffling. We identify sponges cnidarians a transmembrane protein, Hedgling, contains amino-terminal, signalling (hedge-domain), cadherin, EGF immunoglobulin domains. While Hedgling appears been lost bilaterians, capture hedge-domain more ancient, intein derived hog-domain may given rise proteins.