Fast and furious 800. the retinal determination gene network in Drosophila

Abstract

The Drosophila compound eye is formed by about 800 ommatidia or simple eyes, packed in an almost crystalline lattice. The precise ommatidial arrangement makes the fly eye especially sensitive to pattern aberrations. These properties, together with the fact that the eye is an external and largely dispensable organ, have made the Drosophila eye an excellent genetic model to investigate the mechanisms of cell proliferation, patterning and differentiation, as well as mechanisms of human disease, such as cancer, neurodegeneration or metabolic pathologies. Part of these studies have coalesced into the Drosophila eye (or retinal) gene regulatory network (GRN): a text-book example of an organ-specification gene network that has been used as a point-of-comparison in the study of the mechanisms of eye specification and evolution, as well as a paradigm of signaling integration. This paper reviews the gene network that covers the period from eye progenitor specification to the onset of retinal differentiation as marked by activation of the proneural gene atonal, while paying special attention to the dynamics of the network and its intimate relation to the control of eye size.