Cloning of a cDNA encoding cathepsin D from salamander, Hynobius leechii, and its expression in the limb regenerates

Cathepsin D is a major lysosomal aspartic proteinase participating in the d egradation or modification of intra- and extracellular matrix molecules, an d its activity is known to increase in the process of tissue reorganization during the early phase of salamander limb regeneration. Here, we report th e cloning of a salamander cathepsin D cDNA from Hynobius leechii and its ex pression profile in normal and retinoic acid (RA) treated limb regenerates. The gene expression of cathepsin D increased notably during the dedifferen tiation stage and decreased gradually thereafter. Furthermore, RA that enha nces dedifferentiation of regenerating salamander limb caused the elevation of cathepsin D expression both in terms of level and duration. These resul ts suggest that cathepsin D plays important role(s) in the dedifferentiatio n process, and enhancement of cathepsin D expression might be closely relat ed to RA-evoked pattern duplication.