B6.129S2(Cg)-Msx1^{tm2.1(cre/ERT2)Bero}/J

Stock number: 027850
Product name: Msx1^CreERT2
Research areas: Cell Biology Research, Developmental Biology Research, Internal/Organ Research, Research Tools

Description

These mice express tamoxifen-inducible Cre recombinase under the direction of the Msx1 promoter during organogenesis.

Detailed description

Msx1^CreERT2 mice express a Cre-ERT2 fusion protein from endogenous msh homeobox 1 (Msx1) promoter/enhancer elements. MSX1 acts as a transcriptional repressor during organogenesis, specifically during the development of the palate, teeth, and nails. CreERT2 interrupts the Msx1 coding sequence creating a null allele. Heterozygous mice are viable and fertile. Homozygotes die soon after birth because of a cleft palate that prevents the pups from feeding. These homozygous animal also display tooth agenesis and an absence of the subcommisural organ in the forebrain, leading to hydrocephaly. When Msx1^CreERT2 mice are bred with mice containing loxP-flanked sequence, tamoxifen-inducible, Cre-mediated recombination will result in deletion of the floxed sequences.

Development

A targeting vector was designed to insert a CreERT2 (Cre recombinase fused to an estrogen receptor ligand binding domain) coding sequence fused to a polyadenylation sequence, and a frt-flanked neomycin (neo) resistance cassette, into the translation initiation codon of the msh homeobox 1 (Msx1) gene. This construct was electroporated into 129S2/SvPas-derived CK35 embryonic stem (ES) cells. Correctly targeted ES cells were injected into recipient C57BL/6 blastocysts and the resulting chimeric animals were crossed to Tg(ACTFLPe)9205Dym mice to remove the neo selection cassette. Offspring were then crossed to remove the Flp-expressing transgene. These mice were bred to C57BL/6JRj mice for at least 15 generations. Upon arrival at The Jackson Laboratory, mice were bred to C57BL/6J inbred mice (Stock No. 000664) for at least one generation to establish the colony.

Allele

Symbol: Msx1^{tm2.1(cre/ERT2)Bero}
Name: targeted mutation 2.1, Benoit Robert
MGI accession ID: MGI:5049923
Generation method: Targeted
Attributes: Recombinase-expressing; Inducible
Marker symbol: Msx1
Marker name: msh homeobox 1
Chromosome: 5
Strain of origin: 129S2/SvPas
Expressed genes: cre/ERT2,Cre recombinase and estrogen receptor 1 (human) fusion gene,
Site of expression: Cre-ERT2 fusion protein is expressed from Msx1 promoter/enhancer elements during the development of the palate, teeth, and nails.
Molecular note: A targeting vector with the cre/ERT2 sequence, polyadenylation site, and an Frt-flanked neomycin cassette inserted into the ATG site of Msx1 in a plasmid was generated by homologous recombination in bacteria. The linearized targeting vector was electroporated into ES cells and targeted clones were used to generated chimeras. F1 offspring were crossed to Flp deleter mice to delete the neo marker.