Genetic analysis of the role of the Drosophila fat facets gene in the ubiquitin pathway

The Drosophila fat facets gene encodes a deubiquitinating enzyme required d uring eye development to limit the number of photoreceptors in each Facet t o eight. Ubiquitin is a small polypeptide that targets proteins for degrada tion by the proteasome. In order to investigate the role of FAT FACETS in t he ubiquitin pathway, genetic interactions between fat facets and the Droso phila UbcD1 gene were assessed. In addition, three yeast deubiquitinating e nzyme genes were tested for their ability to substitute for fat facets in t he developing Drosophila eye and for their effects on eye morphology. The r esults of these experiments support the hypothesis that FAT FACETS activity antagonizes that of the proteolytic machinery. The implications of these r esults for the specificity of FAF and yeast UBPs are discussed as well. Dev . Genet. 25:312-320, 1999. (C) 1999 Wiley-Liss, Inc.