Alternative titles; symbols
HGNC Approved Gene Symbol: PRR4
Cytogenetic location: 12p13.2 Genomic coordinates (GRCh38) : 12:10,845,849-10,849,475 (from NCBI)
The epithelial surfaces of the eye are protected from desiccation, abrasion, and infectious organisms in the environment by the secretion of tears, a complex fluid produced by glands, particularly the lacrimal gland, surrounding the eye. The proteins present in tears, including PRR4, are involved in mediating the protective functions of this fluid (summary by Dickinson and Thiesse, 1995).
By screening a lacrimal gland cDNA library with a lacrimal gland total cDNA probe, followed by database searches, Dickinson and Thiesse (1995) identified a cDNA encoding a protein that the authors called lacrimal proline-rich protein (LPRP). The deduced 134-amino acid, 13.5-kD protein shares 45.5% sequence similarity with PRH1 (168730). It contains a 16-amino acid signal sequence, 21% proline residues, and an acidic N-terminal region. Southern blot analysis showed that LPRP is a single copy gene. Northern blot and RNase protection analyses revealed high levels of a protected 275-bp fragment in the lacrimal gland, with somewhat lower levels in the submandibular gland and detectable levels in the parotid and sublingual glands. In situ hybridization analysis demonstrated strong expression in the acinar cells but not in the intralobular ducts of the lacrimal gland. In the submandibular gland, serous acini and demilunes stained positive for LPRP and PRH1.
Gross (2022) mapped the PRR4 gene to chromosome 12p13.2 based on an alignment of the PRR4 sequence (GenBank AF530472) with the genomic sequence (GRCh38).
Dickinson, D. P., Thiesse, M. A major human lacrimal gland mRNA encodes a new proline-rich protein family member. Invest. Ophthal. Vis. Sci. 36: 2020-2031, 1995. [PubMed: 7544782]
Gross, M. B. Personal Communication. Baltimore, Md. 1/11/2022.