AXON PATTERNING REQUIRES DN-CADHERIN, A NOVEL NEURONAL ADHESION RECEPTOR, IN THE DROSOPHILA EMBRYONIC CNS

We identified DN-cadherin, a novel Drosophila cadherin that is express ed in axons and in the mesoderm. Although DN-cadherin has diverged fro m vertebrate classic cadherins in terms of its extracellular structure , it still can form a complex with catenins and induce cell aggregatio n, as do the vertebrate molecules. Loss-of-function mutations of the g ene resulted in either embryonic lethality or uncoordinated locomotion of adults. In the central nervous system of null mutant embryos, subs ets of ipsilateral axons displayed a variety of aberrant trajectories including failure of position shifts, defective bundling, and errors i n directional migration of growth cones. These results suggest that pr ocesses of axon patterning critically depend on DN-cadherin-mediated a xon-axon interactions.