NEUROTACTIN FUNCTIONS IN CONCERT WITH OTHER IDENTIFIED CAMS IN GROWTHCONE GUIDANCE IN DROSOPHILA

We have isolated and characterized mutations in Drosophila neurotactin , a gene that encodes a cell adhesion protein widely expressed during neural development. Analysis of both loss and gain of gene function co nditions during embryonic and postembryonic development revealed speci fic requirements for neurotactin during axon outgrowth, fasciculation, and guidance. Furthermore, embryos of some double mutant combinations of neurotactin and other genes encoding adhesion/signaling molecules, including neuroglian, derailed, and kekkon1, displayed phenotypic syn ergy. This result provides evidence for functional cooperativity in vi vo between the adhesion and signaling pathways controlled by neorotact in and the other three genes.