Abstract:

Cathepsin D is lysosomal endoproteolytic enzyme which is thought to play key roles in the developmental and physiological process in organisms. The nucleic acid sequence of reported silkworm cathepdin D was used to tBLASTn search against the silkworm EST database. The ESTs with high score were clustered and assembled into a consensus sequence. Based on the consensus sequence, the aspartic proteases of Bombyx mori was cloned and identified,  termed as BmCtD (GenBank accession number: DQ010007). The cDNA was 1 543 bp at length with an open reading frame of 1 152 bp, and there were alternative splices in BmCtD. The deduced amino acid sequence of the BmCtD shared high similarity with that of cathepsin D in other species. The results of RT-PCR showed that the gene was expressed at all examined  developmental stages and tissues of B. mori.

Key words: Bombyx mori, cathepsin D, clone, sequence analysis, expression