Opsins are members of the G protein-coupled receptor superfamily. In addition to the visual opsins, mammals possess several photoreceptive non-visual opsins that are expressed in tissues outside the eye. The opsin-3 gene is strongly expressed in brain and testis and weakly expressed in liver, placenta, heart, lung, skeletal muscle, kidney, and pancreas. The gene is expressed in the skin and may also be expressed in the retina. The protein has the canonical features of a photoreceptive opsin protein.
^Blackshaw S, Snyder SH (May 1999). "Encephalopsin: a novel mammalian extraretinal opsin discretely localized in the brain". The Journal of Neuroscience. 19 (10): 3681–90. PMID10234000.
^Halford S, Freedman MS, Bellingham J, Inglis SL, Poopalasundaram S, Soni BG, Foster RG, Hunt DM (Mar 2001). "Characterization of a novel human opsin gene with wide tissue expression and identification of embedded and flanking genes on chromosome 1q43". Genomics. 72 (2): 203–8. doi:10.1006/geno.2001.6469. PMID11401433.
Bonaldo MF, Lennon G, Soares MB (Sep 1996). "Normalization and subtraction: two approaches to facilitate gene discovery". Genome Research. 6 (9): 791–806. doi:10.1101/gr.6.9.791. PMID8889548.
Halford S, Bellingham J, Ocaka L, Fox M, Johnson S, Foster RG, Hunt DM (2002). "Assignment of panopsin (OPN3) to human chromosome band 1q43 by in situ hybridization and somatic cell hybrids". Cytogenetics and Cell Genetics. 95 (3-4): 234–5. doi:10.1159/000059351. PMID12063405.
Kasper G, Taudien S, Staub E, Mennerich D, Rieder M, Hinzmann B, Dahl E, Schwidetzky U, Rosenthal A, Rump A (Jul 2002). "Different structural organization of the encephalopsin gene in man and mouse". Gene. 295 (1): 27–32. doi:10.1016/S0378-1119(02)00799-0. PMID12242008.
Alam NA, Gorman P, Jaeger EE, Kelsell D, Leigh IM, Ratnavel R, Murdoch ME, Houlston RS, Aaltonen LA, Roylance RR, Tomlinson IP (Dec 2003). "Germline deletions of EXO1 do not cause colorectal tumors and lesions which are null for EXO1 do not have microsatellite instability". Cancer Genetics and Cytogenetics. 147 (2): 121–7. doi:10.1016/S0165-4608(03)00196-1. PMID14623461.