Characterization of the mouse and human PRSS17 genes, their relationship to other serine proteases, and the expression of PRSS17 in developing mouse incisors

The human PRSS17 (serine protease 17) gene, which is located on chromosome 19q in a cluster of genes encoding serine proteases, has been variously des ignated enamel matrix serine proteinase 1 (EMSP1), prostase, KLK4, and KLK- L1. We have cloned and characterized the mouse and human PRSS17 genes. Both have six exons and five introns. The mouse PRSS17 gene sequence is 10 134 bp; the human sequence is 7115 bp. Computer analysis of the mouse PRSS17 ge ne sequence upstream of the translation initiation codon identified two pot ential transcription initiation sites, at nucleotides 2878 and 2336. The fi rst nucleotide of the reported mouse PRSS17 cDNA sequence corresponds to po sition 2352 on the gene, only 16 bases downstream from one of the putative transcription initiation sites. Repetitive DNA sequences from the MSR1 fami ly are found in both the mouse and human PRSS17 genes. Additionally, the hu man PRSS17 gene contains Tigger2, MER8, and Alu repetitive sequences. Phylo genetic analyses of human and rodent proteases suggest that the PRSS17 prot ein is not a member of the kallikrein family of serine proteases but that t he PRSS17 gene may have originated prior to the divergence of the kallikrei n and trypsin families of proteases. To better characterize the timing of P RSS17 expression in developing teeth, we performed in-situ hybridization on postnatal day 3 developing mouse mandibular incisors. PRSS17 mRNA was not detected in secretory stage ameloblasts but could be detected in odontoblas ts, while transition-stage and maturation-stage ameloblasts were strongly p ositive. This pattern supports a role for the PRSS17 protein in the degrada tion of enamel proteins. (C) 2000 Published by Elsevier Science B.V. All ri ghts reserved.