THE EYE-SPECIFICATION PROTEINS SO AND EYA FORM A COMPLEX AND REGULATEMULTIPLE STEPS IN DROSOPHILA EYE DEVELOPMENT

sine oculis (so) and eyes absent (eya) are required for Drosophila eye development and are founding members of the mammalian Six and Eya gen e families. These genes have been proposed to act with eyeless (Pax6) to regulate eye development in vertebrates and invertebrates. so encod es a highly diverged homeobox transcription factor and eya encodes a n ovel nuclear protein. We demonstrate that So and Eya (1) regulate comm on steps in eye development including cell proliferation, patterning, and neuronal development; (2) synergize in inducing ectopic eyes; and (3) interact in yeast and in vitro through evolutionarily conserved do mains. We propose that an So/Eya complex regulates multiple steps in e ye development and functions within the context of a network of genes to specify eye tissue identity.