Drosophila eye development is a progressive process including cell fate determination, pattern formation, and rhabdomere morphogenesis. During eye development, a dramatic change in cell shape, which involves turning and extension of the photoreceptor apical surface, occurs in the early pupal stages. It is known that assembly and extension of adherens junctions (AJs) play an important role in this process. In the present study, I show that mutation of the largest subunit of dynactin complexes encoded by Glued (Gl) affects the extension and assembly of Ajs in developing photoreceptors. In Gl(1)/(+) mutants and transgenic flies expressing the dominant negative form of Glued, the AJs failed to properly assemble and extend. In addition, the morphogenesis of rhabdomeres was also affected in these flies. Taken together, these results suggest that the extension and assembly of AJs as well as determination of the rhabdomere domain in photoreceptor development are Gl dependent. Copyright 2004 National Science Council, ROC and S. Karger AG, Basel