Epithelial immaturity and multiorgan failure in mice lacking epidermal growth factor receptor

SINCE the discovery that epidermal growth factor (EGF) can accelerate opening of the eyelids 1 , the EGF receptor (EGF-R) has been extensively studied and is now considered to be a prototype tyrosine kinase receptor 2 . Binding of EGF or of transforming growth fact-or-a (TGF-α) or other related factors activates the receptor and induces cell proliferation and differentiation. Although it is not found on haematopoietic cells, the EGF-R is widely expressed in mammals and has been implicated in various stages of embryonic development 3 . Here we investigate the developmental and physiological roles of this receptor and its ligands by inactivating the gene encoding EGF-R. We find that EGF-R -/- mice survive for up to 8 days after birth and suffer from impaired epithelial development in several organs, including skin, lung and gastrointestinal tract.