Nervig, a new member of the Notch signaling pathway? S. Chandra ¹, A. Ahmed ¹, H. Vaessin ^1,2. 1) MCDB, The Ohio State University, Columbus, OH; 2) Molecular Genetics & Neurobiotechnology Center, The Ohio State University, Columbus, OH.

   The Drosophila gene nervig (ner) represents a new member of the IgC2 superfamily. ner encodes a transmembrane protein with six IgC2 domains in the putative extracellular domain. Proteins belonging to the IgC2 superfamily of cell adhesion and signaling proteins have been shown to be involved in the proper execution of many critical developmental processes. Loss of ner function is recessive lethal and results in a hyperplasia of the embryonic nervous system and a parallel loss of epidermal structures. This phenotype is qualitatively highly similar to the phenotypes displayed by loss of function mutations of the neurogenic genes of the Notch signaling pathway. In addition, we have observed dosage sensitive interactions between ner and mutations in three neurogenic genes: Notch, Delta and Enhancer of split. Therefore, ner function may either be part of the Notch signaling pathway itself, or alternatively, ner function may be closely associated with the functions of this signaling pathway. We will present data from our analysis of the mutant phenotype associated with the loss and gain of ner function, genetic interaction studies with neurogenic genes, as well as data showing that Ner represents one member of a small family of highly conserved IgC2 domain proteins in the Drosophila genome.