Fibroblast growth factors (FGFs) promote the proliferation, differentiation and survival of most neural cell types during development. Kawauchi et al. now report that Fgf8 expression is essential for neurogenesis in mouse olfactory epithelium (see p. ). Around mid-gestation, the olfactory placodes (epithelial patches on the head of developing embryos) invaginate to form nasal pits in which neurogenesis occurs. The researchers show that Fgf8 is expressed in the rim of invaginating nasal pits - they call this region the morphogenetic centre. They then demonstrate that early inactivation of the Fgf8 gene in the olfactory epithelium leads to the apoptosis of cells in the morphogenetic centre. Consequently, nasal invagination ceases and olfactory neurogenesis fails. The researchers conclude that Fgf8 expression is crucial for the morphogenesis of the nasal cavity, and for the survival and subsequent expansion of the stem cell population that generates olfactory neurons.
