Inactivation of the Caenorhabditis elegans APC-related gene (apr-1) has pointed at two separate functions of apr-1. First, apr-1 is required for the migration of epithelial cells during morphogenesis of the embryo. In this process, APR-1 may act in a Cadherin/alpha-Catenin/beta-Catenin complex as a component of adherens junctions. Second, apr-1 is required for Hox gene expression, most likely by positively regulating the activity of the Wingless signaling pathway. During embryogenesis, apr-1 is required for the expression of ceh-13 labial in anterior seam and muscle cells and during larval development, apr-1 is necessary for the expression of lin-39 deformed in the vulval precursor cells. Thus, APR-1 may positively regulate the activity of the beta-Catenin/Armadillo-related proteins HMP-2 in migrating epithelial cells and BAR-1 in the vulval precursor cells.