Characterization and comparative mapping of the porcine CTSL gene indicates a novel synteny between HSA9q21-->q22 and SSC10q11-->q12.

Cathepsin L (CTSL) is a lysosomal cysteine protease with potent elastase and collagenase activities. Its high activity in the uterine lumen during the period of placental attachment has led to speculation that CTSL may play an important role during embryonic implantation in the pig. Cathepsins have also been implicated in blastocyst implantation in other species like cat, rat and man. We isolated a PAC clone containing the porcine CTSL gene and determined the complete DNA sequence of the gene, which spans about 5.6 kb and consists of eight exons. The CTSL transcript encodes a primary peptide of 334 amino acids sharing 73-78% identity with other mammalian cathepsin L precursor proteins. Based on fluorescence in situ hybridization and radiation hybrid mapping, the porcine CTSL gene was assigned to chromosome 10q11--> q12.