We overexpressed two deletion mutants of the N-terminal domain of beta-catenin in ventral optic axons in living Xenopus tadpoles. One deletion mutant contained both the alpha-catenin and the GSK-3beta binding sites of the N-terminal domain of beta-catenin (NTERM), and the second deletion mutant contained only the GSK-3beta binding site (beta-cat107). Expression of NTERM in ventral optic axons dispersed and induced anterior and lateral shifts in their targeting locations in the dorsal tectum. In contrast, beta-cat107 compressed and shifted the synaptic targeting locations of ventral optic axons medially and posteriorly. In addition, NTERM-expressing ventral optic axons formed arbors that were wider than controls whereas beta-cat107 axonal arbors were narrower compared with controls. These data suggest that the interactions of beta-catenin with alpha-catenin and GSK-3beta exert opposing effects on the terminal projections of ventral optic axons.