Structural analysis of a rat renal kallikrein gene

A renal kallikrein gene has been isolated, sequenced and characterized from a rat genomic library using a kallikrein cDNA probe. The kallikrein gene is 4160 bases in length and consists of 5 exons and 4 introns. The deduced sequence of the gene encodes an 18 amino acid (a.a.) signal peptide, a 6 a.a. propeptide and a 237 a.a. active enzyme with an N-terminal valine. A sequence comparison of this and tissue kallikrein (pancreatic kallikrein) indicates the key a.a. residues for serine protease activity (HIS-ASP-SER) and cleavage specificity at basic a.a. Northern blot analysis using a specific oligonucleotide probe reveals that this gene is expressed specifically in the kidney but not in the pancreas. This gene is also expressed non-specifically in the submandibular gland which expresses all kallikrein family genes. The expression of this kidney-specific kallikrein gene is regulated by steroid hormones.