It is shown that four domains of the integral membrane protein crb of Drosophila are homologous with five C-terminal domains of the laminin A chain and merosin. Since the latter domains of laminin A have been implicated in determining epithelial polarity, the homology may suggest a similar function for these domains or crb. Such a function would be consistent with the known importance of crb for organization of epithelia in Drosophila.
