Cx23floxed mice possess loxP sites flanking exon 2 of the gap junction protein, epsilon 1 (Gje1) gene, and a frt-flanked β-galactosidase gene. This strain may be useful for studying genes associated with lens transparency.
Brian Popko, University of Chicago
Cx23floxed mice possess loxP sites flanking exon 2 of the of the gap junction protein, epsilon 1 (Gje1) gene. This allele also contains frt sites flanking both a β-galactosidase gene and a loxP-flanked neo cassette. Gje1 encodes Connexin 23 (CX23) which is expressed in the lens of the eye, with expression also evident in oligodendrocytes and myelinating Schwann cells. Connexins are transmembrane proteins that form conduits between adjacent cells allowing intercellular communication and the transfer of ions and small signaling molecules. When these mutant mice are bred to mice that express Cre recombinase, resulting offspring will have exon 2 deleted in cre-expressing tissues. Cre recombination results in mice expressing a lacZ-tagged null allele. When exon 2 is removed lenses have normal transparency and refractive properties, normal focusing ability, and normal light scattering. They have normal localization of other lens fiber connexins, Cx46 and Cx50, but have altered levels of these proteins. Mice that are homozygous for this allele are viable and fertile.
C57BL/6N-Atm1Brd-derived JM8A3.N1 embryonic stem (ES) cells containing a targeted mutation of the gap junction protein, epsilon 1 (Gje1) gene were obtained from The European Conditional Mouse Mutagenesis Program (EUCOMM). The mutant allele has, from 5’ to 3’, a FRT site, a β-galactosidase and polyA sequence, a loxP site, a neomycin resistance (neo) cassette, a second FRT site, and loxP sites flanking exon 2. Correctly targeted ES cells were injected into C57BL/6J blastocysts. The resulting chimeric animals were tested for germline transmission. Upon arrival, sperm was cryopreserved. To establish our live colony, an aliquot of frozen sperm was used to fertilize C57BL/6NJ oocytes (Stock No. 005304).
|Allele Name||targeted mutation 1c, Helmholtz Zentrum Muenchen GmbH|
|Allele Type||Targeted (Conditional ready (e.g. floxed))|
|Gene Symbol and Name||Gje1, gap junction protein, epsilon 1|
|Strain of Origin||C57BL/6N-Atm1Brd|
|Molecular Note||Flp-mediated excision of the parental Gje1m1a(EUCOMM)Wtsi allele resulted in the removal of the promoter-driven neomycin selection cassette and the inserted lacZ reporter sequence, leaving behind the loxP-flanked critical exon(s). Further information on targeting strategies used for this and other IKMC alleles can be found at http://www.informatics.jax.org/mgihome/nomen/IKMC_schematics.shtml.|
When maintaining a live colony mice homozygous for the floxed allele may be bred together.
When using the Cx23flox mouse strain in a publication, please cite the originating article(s) and include JAX stock #029034 in your Materials and Methods section.