SIGNALING BY HEDGEHOG FAMILY PROTEINS IN DROSOPHILA AND VERTEBRATE DEVELOPMENT

Members of the hedgehog gene family encode a novel class of secreted p roteins and are expressed in embryonic cells known to possess Importan t signalling activities in organisms as diverse as flies and chickens. Proteins of the hedgehog family act in these different developmental contexts as both permissive and instructive signals. How this signalli ng activity is transduced is (as yet) poorly understood, but recent st udies point to the involvement of protein kinase A in both Drosophila acid vertebrates.