Cathepsin L gene organization in crustaceans.

The gene structure of a cathepsin L of the shrimp Penaeus vannamei has been determined by the polymerase chain reaction. It comprises six exons of various lengths spanning a total of 1792bp. This architecture is homologous to that of rat cathepsin L, three conserved sites of intron position have been effectively identified, with the exception of the third intron break-point located immediately after the cysteinyl active site. In contrast, no similarity is observed with Drosophila or Plasmodium cathepsin L-like gene organizations. This gene expresses a major cathepsin L enzyme in the hepatopancreas. The last intron is polymorphic, suggesting the presence of at least three different genes.