Homology of Drosophila yolk proteins and the triacylglycerol lipase family

Drosophila yolk proteins consist of a set of related proteins of 50,000 Mr. They are derived from slightly larger precursors by cleavage of a signal peptide. In this respect, they differ from the yolk proteins of other insects which are proteolytic fragments of precursors of 200,000 Mr or larger, termed vitellogenins and probably homologous to the vitellogenins of other egg-laying species. We report here a comparative amino acid analysis demonstrating that the Drosophila yolk proteins are non-homologous to the vitellogenin group of yolk proteins, but surprisingly are related to the triacylglycerol lipase family.