These floxed mutant mice possess loxP sites flanking exon 2 of the Pax5 gene. This strain may be useful for generating conditional mutations in applications related to B lymphopoiesis, CNS development and spermatogenesis.
Meinrad Busslinger, Research Institute of Molecular Pathology (IMP)
The Pax5 gene encodes a transcription factor important during B cell development, as well as brain development and spermatogenesis. Mutations in the human PAX5 gene are associated with several B-cell lymphomas and leukemias.
These mice possess loxP sites on either side of exon 2 (70 bp upstream and 130 bp downstream of exon 2) of the targeted Pax5 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 exon 2 deleted in the cre-expressing tissues. Removal of the floxed sequence creates a null allele.
When bred to a strain with Cre recombinase expression in B cells during B lymphopoiesis (see Stock No. 006785 for example), this mutant mouse strain may be useful in studies of B cell commitment and development.
A targeting vector containing a loxP site flanked tk-Neo selection cassette was utilized in the construction of this mutant. This selection cassette was inserted downstream of exon 2 of the targeted gene, and another loxP site was inserted upstream of exon 2. This construct was electroporated into 129P2/OlaHsd derived E14.1 embryonic stem (ES) cells which were transiently transfected with a Cre recombinase vector to remove the selection cassette. Correctly targeted ES cells were injected into C57BL/6 blastocysts. The donating investigator reports that the resulting chimeric male animals were backcrossed to wildtype C57BL/6J mice for more than 10 generations, producing Pax5F/+ progeny (see SNP note below).
Upon arrival, sperm was cryopreserved. To establish our live colony, an aliquot of frozen sperm was used to fertilize C57BL/6J oocytes (Stock No. 000664).
A 32 SNP (single nucleotide polymorphism) panel analysis, with 27 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. Four of the 27 markers throughout the genome, as well as 3 markers that determine substrains, were segregating, suggesting an incomplete backcross.
|Allele Name||targeted mutation 3, Meinrad Busslinger|
|Allele Type||Targeted (Conditional ready (e.g. floxed), No functional change)|
|Gene Symbol and Name||Pax5, paired box 5|
|Strain of Origin||129P2/OlaHsd|
|Molecular Note||A loxP site was inserted upstream of exon 2. A floxed neo cassette was inserted downstream of exon 2. Cre-mediated recombination removed the neo cassette and left exon 2 floxed.|
When maintaining a live colony, these mice can be bred as homozygotes.
When using the Pax5 flox mouse strain in a publication, please cite the originating article(s) and include JAX stock #028100 in your Materials and Methods section.