STOCK Mdm2^tm2.1Glo/J

Stock number: 031614
Product name: floxed mdm2 (FM)
Research areas: Cancer Research, Cardiovascular Research, Developmental Biology Research, Neurobiology Research, Research Tools

Description

These floxed mutant mice possess loxP sites flanking exons 5 and 6 of the Mdm2 gene. This strain may be useful for generating conditional mutations in applications related to the role of the MDM2/MDMX-p53 pathway in embryogenesis, development and tumorigenesis.

Detailed description

The targeted Mdm2 gene encodes a nuclear E3 ubiquitin ligase that tags TRP53 (p53) tumor suppressor protein for proteasomal degradation. Mutations in and overexpression of this gene have been associated with human cancers.

These floxed mdm2 (FM) mice possess loxP sites flanking exons 5 and 6 of the Mdm2 gene. 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 exons 5 and 6 of the Mdm2 gene deleted in the cre-expressing tissues. Removal of the floxed sequences creates a null allele.

When bred to a strain with Cre recombinase expression in cardiac muscle cells (see Stock No. 011038 for example), this mutant mouse strain may be useful in studies of heart development.

When bred to the floxed Mdm4 strain (Stock No. 030986) and a strain with Cre recombinase expression in the central and peripheral nervous system (see Stock No. 003771 for example), this mutant mouse strain may be useful in studies of neuronal development.

Development

A targeting vector containing a loxP site flanked neo selection cassette was utilized in the construction of this mutant. This selection cassette was inserted downstream of exon 6 of the targeted gene, and another loxP site was inserted upstream of exon 5 (in intron 4). This construct was electroporated into 129S7/SvEvBrd-Hprt⁺ derived AB-1 embryonic stem (ES) cells. Correctly targeted ES cells were injected into C57BL/6J blastocysts. The resulting chimeric animals were crossed to transgenic mice (on the C57BL/6J genetic background) expressing Cre recombinase under the control of the CMV promoter. Mice that retained the loxP site flanked exons 5 and 6, floxed Mdm2 (FM), were then bred to C57BL/6 mice to remove the Cre recombinase transgene. The mice were backcrossed to C57BL/6 for 3 generations by the donating lab (see SNP note below). To establish our live colony, an aliquot of frozen sperm was used to fertilize C57BL/6J oocytes (Stock No. 000664).



A 48 SNP (single nucleotide polymorphism) panel analysis, with 43 markers covering all 19 chromosomes and the X chromosome, as well as 5 markers that distinguish between the C57BL/6J and C57BL/6N substrains, was performed on the rederived living colony at The Jackson Laboratory Repository. Markers on Chormosomes 17 and 19 were segregating with an unknown contributor. Also, four other markers were segregating with 129 suggesting an incomplete backcross.

Allele

Symbol: Mdm2^tm2.1Glo
Name: targeted mutation 2.1, Guillermina Lozano
MGI accession ID: MGI:2385439
Generation method: Targeted
Attributes: Conditional ready (e.g. floxed); No functional change
Synonyms: FM
Marker symbol: Mdm2
Marker name: transformed mouse 3T3 cell double minute 2
Marker synonyms: 1700007J15Rik; ACTFS; hdm2; HDMX; LSKB; Mdm-2; transformed mouse 3T3 cell double minute 2
Chromosome: 10
Strain of origin: 129S7/SvEvBrd-Hprt1⁺
Molecular note: The floxed neo cassette of Mdm2^tm2Glo was excised from intron 6 via germline expression of cre recombinase. Exons 5 and 6, encoding most of the Trp53-binding domain (residues 53 through 113), were left flanked by single loxP sites in introns 4 and 6.