Signal Transduction during Craniofacial Development

cesses in terms of the cell. This important step forward in the history of embryology continues to provide the intellectual framework upon which the majority of current developmental studies is based. This is particularly evident upon review of the literature dealing with the developing palate. Drawing in part from this valuable data base of descriptive studies, this overview deals with cellular and biochemical aspects of the developing palate and provides a discussion of facts and prob- lems in the field, with particular emphasis on recent devel- opments in the challenging area of regulation of hormone- and growth factor-induced transmembrane signaling and intracell- ular signal transduction. This review is also intended to point out possible research directions that, based on our current knowledge, may, if pursued, provide us with a better under- standing of the cellular and molecular basis of craniofacial ontogeny.