Genes regulating dendritic outgrowth, branching, and routing in Drosophila

Signaling between neurons requires highly specialized subcellular structure s, including dendrites and axons. Dendrites exhibit diverse morphologies ye t little is known about the mechanisms controlling dendrite formation in vi vo. We have developed methods to visualize the stereotyped dendritic morpho genesis in living Drosophila embryos. Dendrite development is altered in pr ospero mutants and in transgenic embryos expressing a constitutively active form of the small GTPase cdc42. from a genetic screen, we have identified several genes that control different aspects of dendrite development includ ing dendritic outgrowth, branching, and routing. These genes include kakapo , a large cytoskeletal protein related to plectin and dystrophin; flamingo, a seven-transmembrane protein containing cadherin-like repeats; enabled, a substrate of the tyrosine kinase Abl; and nine potentially novel loci. The se findings begin to reveal the molecular mechanisms controlling dendritic morphogenesis.