Abstract
During animal development, cell adhesion plays a critical role in tissue repair, regeneration and morphogenesis. Different adhesive interactions between cells promote the recognition and assembly of cells with similar properties and also lead them to segregate into distinct cell populations. In Drosophila wing imaginal discs, several components involve in the regulation of cell adhesion at adherens junctions (AJs). Echinoid (Ed) is an immunoglobulin domain-containing cell adhesion molecule (CAM) that localizes to AJs. Drosophila E-Cadherin (DE-cad), the major CAM of AJs, cooperates with Ed to mediate adhesion in wing discs. And another CAM called Friend of echinoid (Fred), which is a paralogue of Ed, is also predicted to provide some efforts in regulating adhesion in AJs. In this study, we combine several RNAi and overexpression experiments to comprehend the relations between Ed, Fred and DE-cad. Overexpression of Fred in ed RNAi clones can not only rescue the sorting phenotype but further trigger the clone cells to scatter. During this process, DE-cad decreases passively at the contact sites, and the differential distributions of Ed, Fred and DE-cad between clone and wild-type cells finally induce the scattering phenotype. Our study reveals that, although sharing high similarity with Ed, the adhesive function of Fred is different from Ed.