In these p53LSL-25,26 mice, which carry a mutation in the first transcriptional activation domain, expression of the mutant TRP53 protein is silenced until Cre recombinase mediates excision of the upstream floxed STOP cassette. These mice may be useful in studies of p53 function and the role of p53 as a transcriptional activator in tumor suppression.
Laura Attardi, Stanford University Medical Center
The Trp53, transformation related protein 53, gene encodes the p53 tumor suppressor protein, which functions as a transcription factor regulating expression of more than 100 target genes. Mutations resulting in inactivation of p53 protein facilitates tumor progression. These p53LSL-25,26 mice carry amino acid substitutions L25Q and W26S in exon 2, which encodes the first transcriptional activation domain of the protein, and a floxed STOP cassette upstream of exon 2. Expression of the mutant TRP53 protein is silenced until Cre recombinase mediates excision of the floxed STOP cassette. After Cre recombinase mediated removal of the floxed STOP cassette cells from the resulting mice exhibit impaired transactivation of many p53 target genes, including Cdkn1a, Pmaip1, and Bbc3, but retains the ability to activate a small subset of target genes, including Bax. Mice that are homozygous for the targeted mutation are viable, but have decreased fertility.
For example, when bred to B6.129-Gt(ROSA)26Sortm1(cre/ERT2)Tyj/J mice (Stock No. 008463) tamoxifen induced Cre recombinase expression in offspring reduces apoptosis following radiation treatment.
A targeting vector designed by Dr. Laura D. Attardi (Stanford University School of Medicine) containing a floxed STOP element with 4 poly adenylation sites, and a puromycin resistance cassette, was utilized to insert the floxed STOP cassette upstream of exon 2 and the L25Q and W26S mutations into exon 2. The construct was electroporated into 129S4/SvJae derived J1 embryonic stem (ES) cells. Correctly targeted ES cells were injected into blastocysts. The resulting chimeric animals were crossed to 129 Sv/J mice.
Upon arrival at The Jackson Laboratory, the mice were crossed to 129S1/SvImJ (Stock No. 002448) at least once to establish the colony.
|Allele Name||targeted mutation 1, Laura D Attardi|
|Allele Type||Targeted (Conditional ready (e.g. floxed), No functional change)|
|Gene Symbol and Name||Trp53, transformation related protein 53|
|Strain of Origin||129S4/SvJae|
|Molecular Note||A knock in strategy was used to introduce a loxP-Stop-loxP transcriptional stop element upstream of exon 2 and L25Q and W26S substitutions into exon 2. Northern and Western blots of mutant MEFs treated with adeno-virus cre demonstrated that transcript and protein were expressed, respectively. No expression is seen without Cre expression.|
When maintaining a live colony, these mice can be bred as heterozygotes. Homozygotes exhibit decreased fertility.
When using the p53LSL-25,26 mouse strain in a publication, please cite the originating article(s) and include JAX stock #022070 in your Materials and Methods section.