drICE17 encodes for an unstable protein. (a) Alignment of the amino-acid residues surrounding Asn116 in DrICE and various effector caspases in insects and mammals, and human Caspase-9. drICE17 carries a mutation in Asn116, changing it to Tyr. Dm, Drosophila melanogaster; Dp, Drosophila pseudoobscura; Ag, Anopheles gambiae; Sf, Spodoptera frugiperda; Bm, Bombyx mori; Mm, Mus musculus; Hs, Homo sapiens. (b) Embryonic extract obtained from homozygous ey-Flp; FRT82B (the stock used for mutagenesis) and drICE17 mutant flies were analyzed by immunoblotting using an antibody raised against the prodomain of DrICE (upper panel). Lower panel is the same blot probed with antiactin antibody as loading control. The arrow indicates full-length DrICE, the asterisk an unspecific protein