Photoreceptor cell-specific nuclear receptor

The photoreceptor cell-specific nuclear receptor (PNR), also known as NR2E3 (nuclear receptor subfamily 2, group E, member 3), is a protein that in humans is encoded by the NR2E3 gene.^[5] PNR is a member of the nuclear receptor super family of intracellular transcription factors.

NR2E3
Available structures PDB Ortholog search: PDBe RCSB List of PDB id codes 4LOG
Identifiers
Aliases	NR2E3, Nr2e3, A930035N01Rik, PNR, RNR, rd7, ESCS, RP37, nuclear receptor subfamily 2 group E member 3
External IDs	OMIM: 604485; MGI: 1346317; HomoloGene: 84397; GeneCards: NR2E3; OMA:NR2E3 - orthologs
Gene location (Human) Chr. Chromosome 15 (human)[1] Band 15q23 Start 71,792,638 bp[1] End 71,818,259 bp[1]
Gene location (Mouse) Chr. Chromosome 9 (mouse)[2] Band 9 B|9 32.35 cM Start 59,850,054 bp[2] End 59,867,942 bp[2]
RNA expression pattern Bgee Human Mouse (ortholog) Top expressed in buccal mucosa cell testicle secondary oocyte gonad retinal pigment epithelium right uterine tube tendon of biceps brachii prostate fundus Descending thoracic aorta Top expressed in neural layer of retina outer nuclear layer retinal pigment epithelium epithelium of lens zygote embryo epithelium of small intestine secondary oocyte primary oocyte ileum More reference expression data BioGPS More reference expression data
Gene ontology Molecular function DNA binding DNA-binding transcription factor activity zinc ion binding metal ion binding steroid hormone receptor activity nuclear receptor activity RNA polymerase II cis-regulatory region sequence-specific DNA binding DNA-binding transcription activator activity, RNA polymerase II-specific sequence-specific DNA binding Cellular component transcription regulator complex nucleoplasm nucleus Biological process phototransduction regulation of transcription, DNA-templated response to stimulus negative regulation of transcription by RNA polymerase II transcription by RNA polymerase II transcription, DNA-templated retina development in camera-type eye eye photoreceptor cell development transcription initiation from RNA polymerase II promoter negative regulation of cell population proliferation steroid hormone mediated signaling pathway signal transduction visual perception intracellular receptor signaling pathway positive regulation of transcription by RNA polymerase II Sources:Amigo / QuickGO
Orthologs Species Human Mouse Entrez 10002 23958 Ensembl ENSG00000278570 ENSMUSG00000032292 UniProt Q9Y5X4 Q9QXZ7 RefSeq (mRNA) NM_001281446 NM_014249 NM_016346 NM_013708 RefSeq (protein) NP_055064 NP_057430 NP_038736 Location (UCSC) Chr 15: 71.79 – 71.82 Mb Chr 9: 59.85 – 59.87 Mb PubMed search [3] [4]
Wikidata
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Function

PNR is exclusively expressed in the retina. The main target genes of PNR are rhodopsin and several opsins which are essential for sight.^[6]

Structure and ligands

The crystal structure of PNR's ligand-binding domain is known. It self-dimerizes into, by default, a repressor state. Computer simulations based on this model shows that a ligand could possibly fit into PNR and switch it into a transcription activator. 13-cis retinoic acid is a known weak agonist that fits into such a pocket, but no physiologic ligand is known. Two synthetic compounds, 11A and 11B, appear to be agonists but do not go into the pocket and instead work as allosteric modulators.^[7] A more recent screening identifies another compound called photoregulin-1 (PR1) that functions as a reverse agonist, an activity possibly useful in the management of retinitis pigmentosa.^[8]

Clinical significance

Mutations in the NR2E3 gene have been linked to several inherited retinal diseases, including enhanced S-cone syndrome (ESCS),^[9] a form of retinitis pigmentosa,^[10] and Goldmann-Favre syndrome.^[11]