RHO Gene (Rhodopsin): Structure, Function, and Clinical Significance
A comprehensive biomedical overview of the RHO gene, encoding the visual pigment rhodopsin, its role in phototransduction, associated diseases, expression patterns, and mutation landscape.
Gene Information Card
| Symbol | RHO |
|---|---|
| Full Name | Rhodopsin |
| Gene Type | protein coding |
| Chromosomal Location | 3q22.1 |
| NCBI Gene ID | 6010 ncbi.nlm.nih.gov/gene/6010 |
| Ensembl ID | ENSG00000163914 |
| UniProt ID | P08100 |
| OMIM ID | 180380 |
| HGNC ID | 10012 |
| Aliases | RP4, CSNBAD1, OPN2 |
Description
The RHO gene encodes rhodopsin, a G protein-coupled receptor (GPCR) that is the essential photopigment in rod photoreceptor cells of the retina. Rhodopsin consists of the protein opsin covalently linked to the chromophore 11-cis-retinal. Upon absorption of a photon, 11-cis-retinal isomerizes to all-trans-retinal, triggering a conformational change in the protein that activates the phototransduction cascade, ultimately leading to a hyperpolarization of the rod cell and signal transmission to the brain. Mutations in RHO are a major cause of inherited retinal dystrophies, including retinitis pigmentosa and congenital stationary night blindness.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Retinitis pigmentosa (RP) | Mutations in RHO cause autosomal dominant (adRP) or autosomal recessive (arRP) forms. Most mutations are missense and exert a dominant-negative effect, leading to protein misfolding, ER stress, and rod cell death. | ClinVar, OMIM |
| Congenital stationary night blindness (CSNB) | Specific mutations (e.g., G90D, T94I) cause constitutive activation of rhodopsin or altered G protein coupling, leading to impaired rod function without progressive degeneration. | ClinVar, OMIM |
| Retinitis pigmentosa 4 (RP4) | RP4 is an allelic variant of RHO-related RP, characterized by early-onset night blindness and progressive visual field loss. | OMIM |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Eye (retina) | High (nTPM ~ 1000) | Rod photoreceptor-specific expression |
| Brain | Low | Minimal expression |
| Other tissues | Not detected | No significant expression |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| Y79 (retinoblastoma) | High | Retinal origin, expresses photoreceptor genes |
| WERI-Rb-1 | Moderate | Retinoblastoma cell line |
| HeLa | Not detected | Non-retinal cell line |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| Pro23His | Missense | ~10% of adRP cases in US | Dominant-negative; protein misfolding and ER retention |
| G90D | Missense | Rare | Constitutive activation; causes CSNB |
| T94I | Missense | Rare | Constitutive activation; causes CSNB |
| Gln64ter | Nonsense | Rare | Loss of function; recessive RP |
| Val137Met | Missense | Rare | Dominant-negative; severe adRP |
Mutation functional classification
Loss of Function (LOF)
Loss-of-function mutations (e.g., nonsense, frameshift) lead to haploinsufficiency or complete loss of rhodopsin, causing autosomal recessive retinitis pigmentosa. These mutations often result in truncated or non-functional protein.
Gain of Function (GOF)
Gain-of-function mutations (e.g., G90D, T94I) cause constitutive activation of the phototransduction cascade in the absence of light, leading to continuous signaling and rod dysfunction, as seen in congenital stationary night blindness.
Dominant Negative (DN)
Dominant-negative mutations (e.g., Pro23His) produce misfolded rhodopsin that accumulates in the endoplasmic reticulum, triggering the unfolded protein response and apoptosis of rod cells. This mechanism underlies autosomal dominant retinitis pigmentosa.
View complete mutation data：
Gene Ontology (GO)
| • G protein-coupled receptor activity | • photoreceptor activity |
| • signal transducer activity | • visual perception |
| • phototransduction | • response to light stimulus |
| • membrane | • integral component of plasma membrane |
Pathways
• Phototransduction cascade
• G alpha (s) signaling events
• GPCR downstream signaling
• Retinoid metabolism and transport
Protein Summary
Rhodopsin is a 348-amino acid integral membrane protein with seven transmembrane helices, typical of GPCRs. It is highly expressed in rod outer segments. The protein binds 11-cis-retinal via a Schiff base to Lys296. Upon light activation, it undergoes conformational changes to activate transducin (Gt), initiating the phototransduction cascade. Post-translational modifications include glycosylation and palmitoylation. Mutations affecting protein folding, stability, or signaling are linked to retinal diseases.
Related Services
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| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| RHOG Knockout HEK293 Cell Line | EDJ-KQ1912 | Human | 391 | Details Get a Quote |
| RHOV Knockout HEK293 Cell Line | EDJ-KQ1915 | Human | 171177 | Details Get a Quote |
| RHOT2 Knockout HEK293 Cell Line | EDJ-KQ3200 | Human | 89941 | Details Get a Quote |
| RHOB Knockout HEK293 Cell Line | EDJ-KQ4084 | Human | 388 | Details Get a Quote |
| RHOH Knockout HEK293 Cell Line | EDJ-KQ4090 | Human | 399 | Details Get a Quote |
| RHO Knockout HEK293 Cell Line | EDJ-KQ5660 | Human | 6010 | Details Get a Quote |
| RHOBTB1 Knockout HEK293 Cell Line | EDJ-KQ6800 | Human | 9886 | Details Get a Quote |
| RHOBTB3 Knockout HEK293 Cell Line | EDJ-KQ7685 | Human | 22836 | Details Get a Quote |
| RHOBTB2 Knockout HEK293 Cell Line | EDJ-KQ7903 | Human | 23221 | Details Get a Quote |
| RHOD Knockout HEK293 Cell Line | EDJ-KQ9118 | Human | 29984 | Details Get a Quote |
| RHOXF2 Knockout HEK293 Cell Line | EDJ-KQ10111 | Human | 84528 | Details Get a Quote |
| RHOF Knockout HEK293 Cell Line | EDJ-KQ10778 | Human | 54509 | Details Get a Quote |
| RHOU Knockout HEK293 Cell Line | EDJ-KQ11995 | Human | 58480 | Details Get a Quote |
| RHOJ Knockout HEK293 Cell Line | EDJ-KQ15063 | Human | 57381 | Details Get a Quote |
| RHOT1 Knockout HEK293 Cell Line | EDJ-KQ15064 | Human | 55288 | Details Get a Quote |
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