Sequence analysis, and chromosomal localization of a gene encoding a cystatin-like protein from Drosophila melanogaster.

Using polyclonal antibodies raised against a Drosophila Ca2(+)-binding protein (DCABP-23), clones were isolated from a Drosophila head cDNA library constructed in the expression vector lambda gt11. Two non-homologous clones have been isolated and are being subjected to sequence analysis. One of these clones, though not encoding DCABP-23, does encode a Drosophila cystatin-like protein. This presumed Drosophila cystatin shows homology to mammalian cystatins, chicken egg white cystatin and the rice oryzacystatin. The Drosophila cystatin has been mapped, by in situ hybridization, to region 88C on the right arm of the third chromosome.