THE ROLE OF THE NOTCH RECEPTORS IN INTERCELLULAR

The Notch gene was discovered in Drosophila at the beginning of the ce ntury and is currently the subject of intensive investigation, not onl y in invertebrates but also in vertebrates where remarkably well conse rved homologues have been recently found. Notch encodes a new kind of cellular receptor whose functioning is still unclear and plays a role in a large number of cell interactions throughout development and in t issue renewal in the adult. Detailed study in invertebrates of some of these interactions has led to the identification of other genes requi red for transduction of the signal initiated by the receptor. Notch is always involved in processes where cells have the potential to choose between several different programmes of differentiation. Cells adopt a specific developmental pathway as a result of the inhibition of some programmes through Notch signalling. In this review we discuss the co ntribution of different experimental models to an understanding of the role of Notch in intercellular signalling.