Mouse Prostasin Gene Structure, Promoter Analysis, and Restricted Expression in Lung and Kidney

Abstract

Human prostasin is a membrane-anchored serine peptidase hypothesized to regulate lung epithelial sodium transport. It belongs to a unique family of genes on chromosome 16p11.2/13.3. Here we describe genomic cloning, promoter analysis, and expression of prostasin's mouse ortholog. The 4.3-kb mouse prostasin gene (prss8) has a six-exon organization identical to human prostasin. Prss8 spans two signal tagged-sites localized to chromosome 7. Multiple mRNA transcripts arise from two consensus initiator elements of a TATA-less promoter and an alternatively spliced, 5' untranslated region intron. Reporter assay establishes that the initiator elements and a GC-rich domain comprise the core promoter and identifies 5' flanking regions with strong enhancer and repressor activity. The 3' untranslated region overlaps the 3' untranslated region of the Myst1 gene oriented tail-to-tail at this locus. Prss8 is highly transcribed in pancreas, kidney, submaxillary gland, lung, thyroid, prostate, and epididymis, and is developmentally regulated. Using selective riboprobes and antibodies to mouse prostasin, we localized its expression to lung airway epithelial and alveolar type II cells and kidney cortical tubule epithelium. Mouse prostasin highly resembles its human ortholog in gene organization and tissue specificity, including strong expression in pulmonary epithelium, suggesting that mice will be useful for probing prostasin's functions in vivo.

Prostasin, a membrane-anchored serine peptidase, regulates sodium currents in JME/CF15 cells, a cystic fibrosis airway epithelial cell line

“…Prostasin has been implicated by several groups of investigators, including our own, in regulation of Na ϩ transport in mammalian epithelia (3,8,19,26,29,30). These suspicions are based on prostasin's phylogenetic similarity to a channelactivating peptidase in frog kidney cells (26,28), coexistence of prostasin and ENaC in several types of epithelia (29), identification of serine peptidase inhibitor-sensitive Na ϩ transport pathways in mammalian airway (3) and kidney (18,19,29) epithelial cells, stimulation of Na ϩ transport when mammalian prostasins and ENaC are expressed together in frog oocytes (8,28), and stimulation of Na ϩ uptake by incubation of mouse kidney cells with soluble prostasin (19). In vivo support for a physiologically significant role in Na ϩ homeostasis comes from studies in rats, which become hypertensive and increase urinary Na ϩ excretion after exposure to adenoviral vectors expressing human prostasin (30).…”

“…Prostate cells can secrete and shed a fraction of prostasins as soluble enzymes with the rest remaining attached by a glycosylphosphatidylinositol anchor (6). Immunolocalization, mRNA blotting, and in situ hybridization studies led to recognition that prostasin is robustly expressed in additional human and mouse tissues, including kidney, lung, and airway (8,26,29,34). Significantly, prostasin shares several similarities with a membrane-anchored frog protein, channel-activating protease, identified by expression cloning as a regulator of Na ϩ transport in Xenopus kidney cells (24,25).…”

Activity and inhibition of prostasin and matriptase on apical and basolateral surfaces of human airway epithelial cells

“…Immunohistochemical studies revealed its presence in epithelial cells of the prostate gland, which inspired naming the enzyme prostasin. Subsequent studies revealed expression by epithelial cells of many organs (36,38). Sequencing of cDNA revealed a sequence predicting initial synthesis as a membrane-anchored, zymogen with an NH 2 -terminal prepro-segment and a COOH-terminal transmembrane peptide anchor (38).…”

“…Expression cloning strategies identified a channel-activating protease (CAP) (34). Data-mining and phylogenetic analysis identified mammalian prostasin as a likely CAP ortholog (8,34,36) alternatively termed CAP1. Among several mammalian epithelial serine proteases with potential to activate ENaC, prostasin/CAP1 is a leading candidate as an endogenous regulator of Na ϩ transport, as reviewed in Ref.…”

GPI-AP release in cellular, developmental, and reproductive biology

“…It was purifi ed as a soluble enzyme from human seminal fl uid and is highly expressed in kidney, lung, pancreas, and prostate in mice and humans ( 26,27 ). As a GPI-AP, PRSS8 can be removed from the cell membrane by treatment with PI-PLC ( 28 ).…”