The Cnih3fl floxed allele has loxP sites flanking exon 4 of the cornichon-3 gene. Removal of the floxed sequence creates a null allele. These mice may be useful in studying the role of synaptic glutamate AMPA receptors in hippocampal synaptic transmission/plasticity, nociception and behavioral, social and cognitive abnormalities, as well as neuropsychiatric disorders such as schizophrenia and depression/mania.
Roger A Nicoll, University of California, San Francisco
Synaptic α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptors (AMPARs) are the dominant glutamate receptor in the brain. AMPARs are regulated by a family of auxiliary subunits known as transmembrane AMPAR regulatory proteins (TARPs) and the additional AMPAR auxiliary subunits/binding proteins (cornichon). Cornichon-2 (Cnih2) and cornichon-3 (Cnih3) promote receptor trafficking and play a critical role in supporting AMPAR-mediated responses. CNIH2 and CNIH3 bind to the GluA1 subunit of AMPAR in hippocampal neurons, allowing GluA1/A2 receptors to reach the surface. CNIH2/CNIH3 interaction with non-GluA1 subunits may be prevented by TARP γ-8 (Cacng8).
The Cnih3fl floxed allele has loxP sites flanking exon 4 of the cornichon-3 gene (Cnih3). When bred to mice that express Cre recombinase, the resulting offspring may be useful in generating a tissue-specific CNIH3 knockout.
For example, when bred to also have the Cnih2fl floxed allele (Stock No. 028442), Cre-mediated knockout of both CNIH2 and CNIH3 in hippocampal neurons results in a profound and selective reduction in AMPAR-evoked excitatory postsynaptic currents (AMPAR-eEPSC) that is similar in amplitude (~20% reduced) but significantly faster in decay compared to CNIH2 deletion alone.
Mice homozygous for the Cnih3fl floxed allele are viable and fertile with no reported abnormalities.
The Cnih3fl floxed allele was created by Dr. Roger A. Nicoll (University of California, San Francisco). First, a targeting vector was designed by to have a loxP site in intron 3, and a frt::loxP::PGK-neoR::frt::loxP cassette in intron 4 of the cornichon homolog 3 (Drosophila) gene (Cnih3) on chromosome 1.
The construct was electroporated into iTL BA1 hybrid (C57BL/6 x 129/SvEv) embryonic stem (ES) cells. Correctly targeted ES cells were injected into recipient blastocysts, and chimeric males were bred with C57BL/6J females to establish the colony.
The donating investigator reports that offspring were bred with Flp-transgenic mice (C57BL/6J genetic background) for germline deletion of the neomycin resistance cassette. The resulting Cnih3fl mice were bred together for several generations (and the Flp-expressing transgene was removed). Cnih3fl homozygous males (black coat color) on a C57BL/6;129 genetic background were sent to The Jackson Laboratory Repository in 2017.
Upon arrival, sperm was cryopreserved. To establish our live colony, an aliquot of frozen sperm was used to fertilize C57BL/6J oocytes (Stock No. 000664).
|Allele Name||targeted mutation 1.1, Roger A Nicoll|
|Allele Type||Targeted (Conditional ready (e.g. floxed), No functional change)|
|Gene Symbol and Name||Cnih3, cornichon family AMPA receptor auxiliary protein 3|
|Strain of Origin||(C57BL/6NTac x 129S6/SvEvTac)F1|
|Molecular Note||A loxP site was inserted upstream of exon 4. An FRT- and loxP-flanked neomycin resistance cassette was inserted downstream of exon 4. Flp-mediated recombination removed the neomycin resistance cassette.|
When maintaining a live colony, heterozygous mice may be bred together or to wildtype mice from the colony. Alternatively, homozygous mice may be bred together.
When using the Cnih3fl mouse strain in a publication, please cite the originating article(s) and include JAX stock #028443 in your Materials and Methods section.