The KLK7 (PRSS6) gene, encoding for the stratum corneum chymotryptic enzyme is a new member of the human kallikrein gene family - genomic characterization, mapping, tissue expression and hormonal regulation

Abstract

The human stratum corneum chymotryptic enzyme (HSCCE; PRSS6, KLK7 gene) has been purified from human stratum corneum and is known to participate in the cell shedding process. The cDNA of the gene has previously been reported. Here, we describe the identification of 5' and 3' extensions of the published mRNA, and the complete genomic organization of the gene. KLK7 is composed of five coding exons which have similar lengths to exons of other kallikrein-like genes. The intron phases are completely conserved between this gene and other members of the kallikrein-like gene family. Precise mapping of KLK7 has indicated that it is located at chromosomal locus 19q13. 3-q13.4 between the already known genes zyme (KLK6) (centromere) and neuropsin (KLK8) (telomere). Until recently, it was thought that this gene is expressed only in the skin. We here provide evidence that KLK7 is also expressed at relatively high levels in the central nervous system, kidney, mammary and salivary glands. Its expression is up-regulated by estrogens and glucocorticoids in the breast carcinoma cell line BT-474. The cDNA and protein of this gene are homologous to sequences of other kallikrein-like genes. The gene encodes for a secreted protein. Phylogenetic analysis, the close structural similarities, and its co-localization in the same chromosomal region, suggest that the gene encoding for the stratum corneum chymotryptic enzyme is a new member of the expanded human kallikrein gene family.