Polymorphism in the human Cathepsin B gene

Abstract

Cathepsin B is a cysteine protease which has been implicated in the development and progression of various cancers. It is often redistributed to the plasma membrane, and inactive forms of the enzyme are commonly found in tumour tissue exudates. The secretion of cathepsin B from cancer cells is thought to correlate with their invasive potential. The purpose of this study was to identify and characterise polymorphism in the human cathepsin B gene. PCR was used in the amplification of exon 7 and intron 7 of the human cathepsin B gene, using primers designed from the reported bovine and human cathepsin B genes. The two resulting amplimers were of different size, revealing a potential polymorphism. 10 human volunteers were screened for this variation, and sequencing of the variant amplimers identified two previously unreported alleles of the human cathepsin B gene. One allele is thought to confer increased stability to the primary transcript for cathepsin B, and hence may alter gene expression in homozygous carriers.