Msx1flox mice may be useful for studying craniofacial morphogenesis, odontogenesis, and natural killer-cell leukemia.
Robert E Maxson, University of Southern California
Msx1flox mice possess loxP sites on either side of exon 2 of the msh homeobox 1 (Msx1) gene. MSX1 acts as a transcriptional repressor during organogenesis, specifically during the development of the palate, teeth, and nails.
MSX1 may also serves as a tumor suppressor gene in natural killer (NK)-cell leukemia.
Mice that are homozygous for this allele are viable and fertile. When these mutant mice are bred to mice that express Cre recombinase, resulting offspring will have exon 2 deleted in cre-expressing tissues.
For example, when bred to Msx2-cre mice expressing cre recombinase in the female germ line, MSX1 deficient mice exhibit a cleft palate.
When bred to Msx2flox mice (Stock No. 025441) and subsequently to mice carrying the Tg(Wnt1-cre)11Rth transgene (Stock No. 009107), mice deficient of MSX1 and MSX2 exhibit defects in the neural crest-derived frontal bone. These mice show an increase in the size of frontal foramen with decreasing Msx gene dosage.
A targeting vector was designed to insert a loxP site and a frt site, followed by a neomycin (neo) selection cassette, and a second set of loxP and frt sites, upstream of exon 2 of the msh homeobox 1 (Msx1) gene. A third loxP site was inserted downstream of exon 2. The construct was electroporated into 129S6/SvEvTac -derived W4 embryonic stem (ES) cells. ES cells were injected into C57BL/6 blastocysts and resulting chimeric males were bred to C57BL/6 females. Resulting offspring were bred to B6.Cg-Tg(ACTFLPe)9205Dym/J transgenic mice (Stock No. 005703) to remove the frt-flanked neo cassette. Further breeding was performed to remove the FLP-expressing transgene. These Msx1flox mice were bred to mice carrying the Msx2tm1Rem floxed allele. The donating investigator reported that they separated the alleles prior to arrival at The Jackson Laboratory. These mice were bred to C57BL/6J (Stock No. 000664) for at least one generation to establish the colony. The Msx2tm1Rem floxed allele is offered as Stock No. 025441.
|Allele Name||targeted mutation 1, Robert Maxson|
|Allele Type||Targeted (Conditional ready (e.g. floxed), No functional change)|
|Gene Symbol and Name||Msx1, msh homeobox 1|
|Strain of Origin||129S6/SvEvTac|
|Molecular Note||A floxed and frt-flanked neo cassette was inserted into intron 1 and an additional loxP site was inserted in intron 2. The neo cassette was removed by flp-mediated recombination.|
When maintaining a live colony, homozygous mice may be bred together.
When using the STOCK Msx1tm1Rem/J mouse strain in a publication, please cite the originating article(s) and include JAX stock #025204 in your Materials and Methods section.