Tentative identification of a resilin gene in Drosophila melanogaster

A search of the Drosophila genome for gene products with similarities to the amino acid sequences of three tryptic peptides from locust (Schistocerca gregaria) resilin gave two positive results: gene products CG15920 and CG9036. In both conceptual translation products a 62-residue region is present, which is identical to the resilin peptides in 29 positions. Gene product CG15920 has an amino acid composition closely resembling that of resilins from various insect species, and it has an N-terminal signal peptide sequence indicating that it is an extracellular protein. The 62-residue region shows similarity to the RR-2 sequence, which is common for a number of matrix proteins from insect solid cuticle. The N- and C-terminal regions flanking the 62-residue in CG15920 are dominated by 18 repeats of a 15-residue sequence and 11 repeats of a 13-residue sequence, respectively. The structures of the repeats predict that the peptide chain will fold in an irregular, extended beta-spiral, resembling the structures suggested for mammalian elastin and spider flagelliform silk, two materials which, like resilin, possess long-range elasticity. Accordingly, we suggest that gene product CG15920 is a Drosophila resilin precursor.