Alternative titles; symbols
HGNC Approved Gene Symbol: OPRPN
Cytogenetic location: 4q13.3 Genomic coordinates (GRCh38): 4:70,397,940-70,410,195 (from NCBI)
Dickinson and Thiesse (1996) isolated a cDNA corresponding to basic proline-rich lacrimal protein (BPLP) from a human lacrimal gland cDNA library representing abundant transcripts. The BPLP gene encodes a putative 180-amino acid protein of 20.5 kD that contains a 21-residue secretory leader sequence, an N-glycosylation site, and a zona pellucida (Zp) domain. The Zp domain of BPLP shows most similarity to that of ZP2 (182888), which carries 2 insertions/deletions of identical size to those in BPLP. The BPLP protein consists of 24.5% proline, 10.5% leucine, and 8.4% each of arginine and serine residues. While the proline residues show 2 regions of clustering, BPLP shows no homology to the salivary proline-rich proteins (e.g., PRB1, 180989). BPLP shows limited homology to human PRPb, the mouse MSG proteins, and rat VCS-alpha-1, VCS-beta-1, and submandibular apomucin. Northern blot analysis showed abundant expression of a 1.05-kb BPLP transcript in the lacrimal gland and moderate expression in the submandibular gland. In situ hybridization showed BPLP expression in lacrimal gland secretory end-piece cells.
Wisner et al. (2006) demonstrated that the analgesic pentapeptide QRFSR, purified from human saliva, originated from the N-terminal region of PROL1. They showed that this peptide, which they called opiorphin, was a physiologic inhibitor of 2 enkephalin-catabolizing enzymes, neutral ecto-endopeptidase (MME; 120520) and ecto-aminopeptidase N (ANPEP; 151530). Opiorphin displayed potent analgesic activity in chemical and mechanical pain models by activating endogenous opioid-dependent transmission. The pain-suppressive potency of opiorphin was as effective as morphine in a behavioral rat model of acute mechanical pain, the pin-pain test.
Gross (2014) mapped the PROL1 gene to chromosome 4q13.3 based on an alignment of the PROL1 sequence (GenBank BC141465) with the genomic sequence (GRCh37).
Dickinson, D. P., Thiesse, M. cDNA cloning of an abundant human lacrimal gland mRNA encoding a novel tear protein. Curr. Eye Res. 15: 377-386, 1996. [PubMed: 8670737] [Full Text: https://doi.org/10.3109/02713689608995828]
Gross, M. B. Personal Communication. Baltimore, Md. 5/29/2014.
Wisner, A., Dufour, E., Messaoudi, M., Nejdi, A., Marcel, A., Ungeheuer, M.-N., Rougeot, C. Human opiorphin, a natural antinociceptive modulator of opioid-dependent pathways. Proc. Nat. Acad. Sci. 103: 17979-17984, 2006. [PubMed: 17101991] [Full Text: https://doi.org/10.1073/pnas.0605865103]