Comparative aspects of Notch signaling in lower and higher eukaryotes

The Drosophila melanogaster Notch gene encodes a receptor that is part of a cell-cell signaling mechanism that is used throughout the development of the fly to regulate a wide variety of cell fate decisions, including some neuronal decisions. The Caenorhabditis elegans Notch-like genes lin-12 and glp-1 play roles that are similar to that of Notch, and studies of this signaling pathway in both organisms have led to models of how the pathway might function. Recent developments in the study of Notch signaling include the isolation of Notch homologs from a variety of vertebrate species. Here we compare what has been learned from studies of Notch-related genes in vertebrates to what is known about Notch signaling in invertebrates, and we discuss the implications of these data for existing models of Notch pathway signaling.