Cathepsin J, a novel murine cysteine protease of the papain family with a placenta-restricted expression

A novel mouse cysteine protease of the papain family was identified by sear ching the dbEST database. A 1.28 kb full-length cDNA was obtained which con tains an open reading frame of 999 nucleotides and encodes a predicted poly peptide of 333 amino acids, The deduced polypeptide exhibits features chara cteristic of cysteine proteases of the papain type including the highly con served residues of the catalytic triad, and was hence named cathepsin J, Ca thepsin J represents the murine homologue of a previously described rat cat hepsin L-related protein. Mature cathepsin J shows 59.3% identity to mouse cathepsin L and contains the characteristic ER(F/W)NIN motif within the pro peptide indicating that this protease belongs to the subgroup of cathepsin L-like cysteine proteases, Northern blot analysis of various tissues reveal ed a placenta-restricted expression. This expression pattern may suggest a role of cathepsin J in embryo implantation and/or placental function. Ctsj was mapped to mouse chromosome 13 in the vicinity of cathepsin L suggesting that cathepsin J may have arisen by gene duplication from cathepsin L or a common ancestral gene. (C) 1999 Federation of European Biochemical Societi es.