These Foxi3flox mice possess loxP sites flanking exon 2 of the forkhead box I3 (Foxi3) gene. FOXI3 is a transcription factor expressed in pre-placodal ectoderm adjacent to the anterior neural plate, and later in the ectoderm and endoderm lining the pharyngeal arches. FOXI3 is required for the development of the entire inner ear, and for branchial arch neural crest survival, patterning, and the subsequent development of branchial arch derivatives. Mice that are homozygous for this allele are viable and fertile. When bred to mice that express tissue-specific Cre recombinase, resulting offspring will have exon 2 deleted in the cre-expressing tissues.
For example, when bred to BALB/c-Tg(CMV-cre)1Cgn/J transgenic mice (Stock No. 003465) expressing Cre recombinase in all tissues, homozygous offspring are embryonic lethal beginning around E9.5, but some homozygous embryos survive until birth and they lack mouth and whiskers. They have severe defects in bone and cartilage development in the head and face, with the mandible being almost completely absent. They also display complete absence of the inner, middle and external ear structures.
A targeting vector was designed to insert a loxP site upstream of exon 2 followed by a frt-flanked neomycin resistance (neo) cassette, and a second loxP site downstream of exon 2 of the forkhead box I3 (Foxi3) gene. The construct was electroporated into 129S6/SvEvTac-derived W4 embryonic stem (ES) cells. Correctly targeted ES cells were injected into blastocysts and resulting chimeric mice were bred to C57BL/6 mice. Resulting offspring were bred to B6.129S4-Gt(ROSA)26Sortm1(FLP1)Dym/RainJ transgenic mice (Stock No. 009086) to removed the neo cassette. Progeny were crossed to remove the FLP transgene. These mice were bred to outbred mice and have been maintained on a mixed background. Upon arrival, mice were bred to C57BL/6J inbred mice (Stock No. 000664) for at least one generation to establish the colony.
|Allele Name||targeted mutation 1.1, Andrew K Groves|
|Allele Type||Targeted (Conditional ready (e.g. floxed), No functional change)|
|Gene Symbol and Name||Foxi3, forkhead box I3|
|Strain of Origin||129X1/SvJ|
|Molecular Note||The targeting vector was designed to insert a loxP site upstream of exon 2 followed by a frt-flanked neomycin resistance (neo) cassette, and a second loxP site downstream of exon 2. FRT-mediated recombination removed the neo cassette.|
When maintaining a live colony, homozygous mice may be bred together.
When using the STOCK Foxi3tm1.1Akg/J mouse strain in a publication, please cite the originating article(s) and include JAX stock #024843 in your Materials and Methods section.