B6.129P2-Runx3^tm1Itan/J

Stock number: 008773
Research areas: Research Tools

Description

Exon 4 of these targeted mutant mice is flanked by loxP sites. When crossed with a Cre recombinase-expressing strain, this strain is useful in eliminating tissue-specific expression of the gene. When crossed to either a CD4-cre or Lck-cre mouse strain, the numbers of CD8⁺ mature thymocytes and CD8⁺ T cells in spleen or lymph nodes are reduced and show defective responses to antigen receptor stimulation.

Detailed description

Exon 4 of these targeted mutant mice is flanked by loxP sites. Mice that are homozygous for this floxed allele are viable, fertile, normal in size and do not display any gross physical or behavioral abnormalities. When crossed with a Cre recombinase-expressing strain, this strain is useful in eliminating tissue-specific expression of the gene.

When crossed to either a CD4-cre or Lck-cre mouse strain, the numbers of CD8⁺ mature thymocytes and CD8⁺ T cells in spleen or lymph nodes are reduced and show defective responses to antigen receptor stimulation. CD8⁺ T cells express CD4 and the ectopic CD4 expression is enhanced when the floxed region is excised.

Development

A loxP-flanked neomycin cassette was placed in intron 3, and an additional loxP site was introduced to intron 4 of the targeted gene. Transient infection with Cre excised the neomycin cassette, leaving exon 4 flanked by loxP sites. This mutation was created in 129P2/OlaHsd-derived E14 embryonic stem (ES) cells. This strain was backcrossed ten times to C57BL/6 (see SNP note below) by the donating laboratory.

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. While the 27 markers throughout the genome suggested a C57BL/6 genetic background, 3 of 5 markers that determine C57BL/6J from C57BL/6N were found to be segregating. These data suggest the mice sent to The Jackson Laboratory Repository were on a mixed C57BL/6J ; C57BL/6N genetic background.

Allele

Symbol: Runx3^tm1Itan
Name: targeted mutation 1, Ichior Taniuchi
MGI accession ID: MGI:3761811
Generation method: Targeted
Attributes: Conditional ready (e.g. floxed); No functional change
Synonyms: Runx3^f; Runx3^flox
Marker symbol: Runx3
Marker name: runt related transcription factor 3
Marker synonyms: AML2; CBFA3; PEBP2aC; Rx3
Chromosome: 4
Strain of origin: 129P2/OlaHsd
Molecular note: A floxed neomycin selection cassette was placed in an adjacent intron of a coding exon and was subsequently removed, leaving behind a single loxP site. A second loxP site was introduced in a downstream intron to "flox" the coding exon.