CRX
Identifiers
Aliases	CRX, CORD2, CRD, LCA7, OTX3, cone-rod homeobox
External IDs	OMIM: 602225 MGI: 1194883 HomoloGene: 467 GeneCards: CRX
Gene location (Human) Chr. Chromosome 19 (human)[1] Band 19q13.33 Start 47,819,779 bp[1] End 47,843,330 bp[1]
Gene location (Mouse) Chr. Chromosome 7 (mouse)[2] Band 7 A2|7 8.6 cM Start 15,599,872 bp[2] End 15,613,893 bp[2]
RNA expression pattern Bgee Human Mouse (ortholog) Top expressed in retinal pigment epithelium right lobe of liver monocyte upper respiratory tract gallbladder gastric mucosa right uterine tube smooth muscle tissue zone of skin skin of abdomen Top expressed in outer nuclear layer inner nuclear layer pineal gland retinal pigment epithelium corneal stroma morula ciliary body conjunctival fornix iris trachea More reference expression data BioGPS More reference expression data
Gene ontology Molecular function DNA-binding transcription activator activity, RNA polymerase II-specific DNA binding leucine zipper domain binding protein binding sequence-specific DNA binding RNA polymerase II cis-regulatory region sequence-specific DNA binding DNA-binding transcription factor activity DNA-binding transcription factor activity, RNA polymerase II-specific Cellular component nucleus Biological process circadian rhythm nervous system development animal organ morphogenesis positive regulation of transcription by RNA polymerase II response to stimulus positive regulation of photoreceptor cell differentiation transcription, DNA-templated multicellular organism development cell differentiation regulation of transcription, DNA-templated visual perception transcription by RNA polymerase II Sources:Amigo / QuickGO
Orthologs Species Human Mouse Entrez 1406 12951 Ensembl ENSG00000105392 ENSMUSG00000041578 UniProt O43186 O54751 RefSeq (mRNA) NM_000554 NM_001113330 NM_007770 RefSeq (protein) NP_000545 NP_001106801 NP_031796 Location (UCSC) Chr 19: 47.82 – 47.84 Mb Chr 7: 15.6 – 15.61 Mb PubMed search [3] [4]
Wikidata
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Cone-rod homeobox protein is a protein that in humans is encoded by the CRX gene.^[5][6][7]

Function

The protein encoded by this gene is a photoreceptor-specific transcription factor which plays a role in the differentiation of photoreceptor cells. This homeodomain protein is necessary for the maintenance of normal cone and rod function. Mutations in this gene are associated with photoreceptor degeneration, Leber's congenital amaurosis type III and the autosomal dominant cone-rod dystrophy 2. Several alternatively spliced transcript variants of this gene have been described, but the full-length nature of some variants has not been determined.^[7]

Mammalian CRX encodes a 299 amino acid protein containing a DNA binding homeodomain (HD) near its N-terminus followed by glutamine rich (Gln), and basic amino acid regions, then a C-terminal transactivation domain (AD).^[8] While structural biochemistry has demonstrated that the CRX HD adopts a canonical homeodomain protein fold, the AD is predicted to be flexible and disordered. The structural attributes of the CRX AD have yet to be solved.^[9]

Evolution

CRX is a divergent duplicate of OTX produced during the 2 rounds of vertebrate whole genome duplication.^[10]

In the eutherian mammals, CRX has again duplicated by tandem gene duplication, with six ancestral duplicates, which are collectively referred to as ETCHbox genes.^[11]