When light brings the dark: The Genetic Complexity of Drosophila stardust During Photoreceptor Morphogenesis and Prevention of Light-Induced Degeneration

In the developing embryo of the fruitfly Drosophila melanogaster the protein Stardust forms a complex with the proteins Crumbs and DPATJ, which is required to maintain epithelial polarity and integrity. In addition, mutations in these genes impair morphogenesis of photoreceptor cells and result in light-dependent retinal degeneration – the flies get blind. The group of Elisabeth Knust has shown that the gene stardust is a genetically complex locus, which encodes several proteins, which may exert different functions. Some of these proteins are only expressed in the embryo, while others can be found only in the eye. These results suggest that Stardust-based protein scaffolds are dynamic, which is not only mediated by multiple interaction partners, but in addition by various forms of the Stardust protein itself. These results have further implications. All proteins of the complex are conserved in human and are expressed in the photoreceptor cells. Loss of CRB1, the homologue of the Drosophila crumbs gene, results in blindness of the affected people.