B6.129S4-Meox2^tm1(cre)Sor/J

Stock number: 003755
Product name: MORE
Research areas: Developmental Biology Research, Research Tools

Description

This knock-in strain expresses Cre recombinase under the control of the endogenous Meox2 promoter with Cre recombinase active in early embryos. These mice can be utilized as a deleter strain for floxed genes and provide an alternative to tetraploid embryo analysis.

Detailed description

This strain expresses Cre recombinase under the control of the endogenous Meox2 promoter. Expression of Cre recombinase is observed in epiblast-derived tissues as early as embryonic day 5. The insertion creates a null allele for the Meox2 gene. Homozygous mice are viable on this background but exhibit an overall reduction in muscle mass and the absence of specific muscles resulting in abnormal limb posture and reduced motility. This phenotype is variable. As many as 80% of homozygotes are severely affected, fail to thrive and die before weaning. Some homozygotes (10%) exhibit clefting of the secondary palate. These mice can be utilized as a deleter strain for loxP flanked DNA and provide an alternative to tetraploid embryo analysis.

Development

A targeting vector containing a nuclear localization sequence-modified Cre recombinase and neomycin resistance genes, linked to a bovine growth hormone polyadenylation was used to replace the first Meox coding exon and 300 base pairs of the following intron in AK7 embryonic stem (ES) cells. Correctly targeted ES cells were used to make chimeric animals which were backcrossed to C57BL/6 mice.

Allele

Symbol: Meox2^tm1(cre)Sor
Name: targeted mutation 1, Philippe Soriano
MGI accession ID: MGI:2176174
Generation method: Targeted
Attributes: Recombinase-expressing
Marker symbol: Meox2
Marker name: mesenchyme homeobox 2
Chromosome: 12
Strain of origin: 129S4/SvJaeSor
Expressed genes: cre,cre recombinase,bacteriophage P1
Site of expression: epiblast-derived tissues as early as embryonic day 5; all primitive ectoderm by embryonic day 7 (but not endoderm or trophectoderm); null allele for Meox2 gene
Molecular note: An nls-cre gene was inserted at the initiator ATG of the gene, followed by a neomycin selection cassette. The endogenous regulatory sequences drive expression by E5 in the epiblast and by E7 expression is detectable in all primitive ectoderm but not endoderm or trophectoderm.