Opn4
Melanopsin (Opsin-4)
Spatial tier: STRICT_EXCLUSIVE · Class: GPCR · Top region: RT (Reticular nucleus of the thalamus) · Positive regions: 4/554
46.8Discovery Score
37.4Targetability Score
CEvidence grade C
What this means: Opn4: predicted fine-region profile is strict-exclusive, with 4 positive regions out of 554 (limit 12); direct spatial validation is required.
Function in RT: evidence, prediction, innovation
- Gene function
- Opn4 encodes melanopsin, an invertebrate-like Gq-coupled opsin photopigment using 11-cis retinal and signalling through PLCbeta onto TRPC6/7-like conductances. In intrinsically photosensitive retinal ganglion cells it drives circadian photoentrainment, the pupillary light reflex, sleep induction and light-dependent mood effects.
- Region function
- The reticular nucleus of the thalamus is the GABAergic shell and only inhibitory gate on thalamocortical relay cells, generating sleep spindles and filtering attention.
- Published in this region
- inferred No region-specific literature found. Outside the retina, mammalian Opn4 is reported essentially only in ipRGCs and retinal pigment epithelium (Peirson et al. 2004); RT is innervated by collaterals of thalamocortical and corticothalamic pathways, not by any documented melanopsin-expressing cell of its own.
- Predicted function
- Prediction: if RT GABAergic neurons truly make melanopsin, they would be weakly and irradiance-dependently depolarized by ambient transcranial light, giving the spindle gate a retina-independent photic bias. RT-restricted Opn4 deletion or local opsinamide (AA92593) should spare pupillary and circadian responses but alter NREM spindle density and arousal thresholds. Mis-assignment is likely, so start with RNAscope for Opn4 in RT cells.
- Innovation
- ★★★★★ 5/5 Extraretinal melanopsin in a thalamic inhibitory gate is unstudied while the readouts (spindles, arousal) are mature, so a positive result would be novel.
- Tools
- Opn4-Cre and Opn4-tau-lacZ reporter mice, Opn4 knockout mice, melanopsin antibodies, and the selective antagonist AA92593 (opsinamide). RT is targetable with Pvalb-Cre, Sst-Cre, Gbx2-CreER and Vgat-Cre plus RT-restricted AAV.
- References
Direct evidence located at the region
No Allen ISH section could be located at this region's centroid for the recorded experiments.
Look it up yourself: Allen Mouse Brain ISH for Opn4Allen reference atlas: RT (structure 262)ABC Atlas MERFISH viewer(in the ABC Atlas choose dataset MERFISH-C57BL6J-638850-CCF, colour cells by gene "Opn4" or by parcellation_substructure "RT")All genes confined to RT + 3-D brain
Direct spatial evidence
MERFISH REGION LOCATOR
DIRECT ALLEN ISH
DIRECT ALLEN ISH
Regional expression figure
Predicted WMB × fine-CCF profile; not direct full-transcriptome spatial measurement.
Spatial profile
Evidence and specificity
- Evidence status
- PREDICTED_FINE
- Direct sources
- None; predicted localization only
- Exclusive threshold
- 12 positive regions out of 554
- Spatial specificity
- 0.351
- Top-region fraction
- 0.133
- Filter status
- PASS
Interpretation limits
- Cell-type-to-region projection is imputed expression, not direct spatial measurement.
- Adult reference atlases do not establish stability across age, sex, strain, state, or disease.
- Transcript abundance does not guarantee protein abundance or genetic-tool performance.