Abstract
It is shown that the proteins encoded by the tumor suppressor fat gene, the neurogenic slit gene and crumbs gene of Drosophila contain domains homologous with modules identified previously in laminin A. These proteins of Drosophila have a number of features in common: they have large extracellular regions containing laminin A modules linked to epidermal growth factor-like domains, and they are all involved in cell-cell interactions that are crucial for correct morphogenesis of ectodermal tissues (development of midline neuroepithelia, organizationof epithelial tissues etc.). It is suggested that the laminin A-type modules of these proteins play important roles in the interactions that control ectodermal differentiation.
