Oh no, Notch again!

The Notch receptor signaling pathway is important for morphogenesis and dev elopment of many organs and tissues in most if not all multicellular specie s. The classical View holds that Notch signaling keeps cells in an undiffer entiated state. Recently, however, this notion has been challenged in the n ervous system by two sets of observations: Notch plays an active role in th e differentiation of glial cells,((1-4)) and Notch influences the length an d organisation of neuronal processes.((5-7)) In this review, we analyse the se recent data and discuss how Notch signaling may be able to perform such quite different tasks during nervous system development. (C) 2001 John Wile y & Sons, Inc.