Cloning of a secretory gelsolin from Drosophila melanogaster.

Gelsolin is an actin-binding protein with the abilities to sever and cap the barbed end of actin filaments and to promote the assembly of monomeric actin. It has been identified in vertebrates both as a cytoplasmic protein and as a protein secreted into the blood plasma. Here we report the nucleic acid sequence of the full-length complementary DNA for a secretory form of gelsolin from Drosophila. The deduced amino acid sequence of 790 residues (M(r) = 87,669) contains a predicted signal peptide of 20 amino acid residues. Comparison of the Drosophila gelsolin sequence with other members of the gelsolin family of actin-binding proteins reveals the characteristic segmental repeat structure found in this class of proteins. A 42% identity is observed between Drosophila secretory gelsolin and human plasma gelsolin when their primary structures are compared. Northern blots resolve a single 3000 base message in third instar Drosophila larvae, a message that appears to be encoded by a single gene located at 82A, B on the right arm of the third chromosome.