Rhodopsin mutations as the cause of retinal degeneration - Classification of degeneration phenotypes in the model system Drosophila melanogaster

Insight into the molecular basis of inherited photoreceptor cell degenerati on has been rapidly evolving during the last decade. The Drosophila Rh1 rho dopsin gene was the first gene shown to cause retinal degeneration when mut ated. Many more degeneration-causing mutations in genes encoding rhodopsin and other photoreceptor proteins have been isolated since then in both, Dro sophila and humans. To date some 70 mutations of the Drosophila Rh1 gene ha ve been isolated, most of them have been characterized at the molecular lev el, and more than 60% of them cause retinal degeneration. This review lists the known Rh1 mutations that cause retinal degeneration up to April 1998, gives an overview on the ultrastructural and biochemical correlates of phot oreceptor cell degeneration, and suggests a system for the classification o f degeneration-causing Rh1 mutations.