STOCK Opn4^{tm3.1(DTA)Saha}/J

Stock number: 035927
Product name: Opn4^DTA
Research areas: Neurobiology Research, Research Tools

Description

Opn4^DTA knock-in/knock-out mice express diphtheria toxin (DTA) under the direction of the Opn4 promoter, resulting in the ablation of intrinsically photosensitive retinal ganglion cells (ipRGCs) at early postnatal stages.

Detailed description

Opn4^DTA knock-in/knock-out mice express the diphtheria toxin subunit alpha (DTA) sequence under the direction of the Opn4 promoter by replacing exons 1-9 of the opsin 4 (melanopsin) (Opn4) gene. Opn4 encodes a photoreceptive opsin protein that is part of the (G protein)-coupled receptor family. Expressed within the melanopsin-expressing retinal ganglion cells and amacrine cell layers of the retina, OPN4 is required for the regulation of circadian rhythms as a result of photosensitivity. Homozygous mice are viable and fertile. These mice express a full-length version of diphtheria toxin (DTA), resulting in the ablation of M1, M2 and M3 intrinsically photosensitive retinal ganglion cells (ipRGCs) at early postnatal stages. Homozygous Opn4^DTA/DTA mice show more substantial and earlier ipRGC loss than heterozygous Opn4^DTA/+ mice.

Of note, a similar strain expressing an attenuated DTA (aDTA) under control of the same promoter is available as Stock No. 035928. Expression of aDTA in Opn4^aDTA mice results in ablation of mostly the M1 ipRGCs only in adults older than 60 days of age.

Development

The Opn4^DTA targeting construct was designed to replace exons 1-9 of the opsin 4 (melanopsin) (Opn4) gene with a diphtheria toxin A (DTA) subunit sequence, an internal ribosomal entry site (IRES), the coding sequence for tauLacZ, and a self-excising neomycin resistance construct (loxP-tAce-Cre-Pol II-Neo-loxP). This construct was electroporated into embryonic stem (ES) cells. Correctly targeted ES cells were injected into blastocysts and the resulting chimeric males were bred to C57BL/6J females. Cre-mediated recombination during spermatogenesis removes the neo cassette leaving one loxP site. Mice were maintained on a mixed genetic background by breeding to B6129SF1/J mice (Stock No. 101043) by the donating lab. Upon arrival at The Jackson Laboratory, sperm was cryopreserved. To establish our live colony, an aliquot of frozen sperm was used to fertilize C57BL/6J oocytes (Stock No. 000664).

Allele

Symbol: Opn4^{tm3.1(DTA)Saha}
Name: targeted mutation 3.1, Samer Hattar
MGI accession ID: MGI:6118195
Generation method: Targeted
Attributes: Reporter; Null/Knockout; Inserted expressed sequence
Synonyms: Opn4^DTA
Marker symbol: Opn4
Marker name: opsin 4 (melanopsin)
Marker synonyms: 1110007J02Rik; MOP
Chromosome: 14
Strain of origin: Not Specified
Molecular note: Exons 1-9 were replaced with a construct containing a diphtheria toxin A gene, IRES, tau-lacZ gene, and self-excising neo cassette. Cre-mediated recombination removed the neo cassette.