EPIDERMAL GROWTH-FACTOR RECEPTOR FUNCTION IN EARLY MAMMALIAN DEVELOPMENT

We review here the data indicating a role for epidermal growth factor receptor (EGF receptor) signalling in early mouse development. Embryon ic development of the metazoan embryo generally begins with the format ion of a cystic structure and epithelial layers that subsequently form anlagen of the definitive body parts and organs. For the mammalian em bryo, this cystic structure is a blastocyst whose walt consists of tro phectoderm, the first epithelium to develop during mammalian embryogen esis. The onset of expression and function of EGF receptors is coincid ent with the onset of trophectoderm development. Modulating EGF recept or expression and function modulates trophectoderm differentiation, le ading to the hypothesis that functional EGF receptors participate in t he induction of trophectoderm development and perhaps of other embryon ic epithelial derivatives such as nervous tissues.