B6.Cg-Foxp3^tm1.1Mal/J

Stock number: 018628
Product name: Foxp3EGFP
Research areas: Research Tools

Description

EGFP is expressed from the forkhead box P3 (Foxp3) locus in these mice. Foxp3 expression is not disrupted. Foxp3⁺ T_reg cells can be identified in these mice by EGFP expression.

Detailed description

An IRES-EGFP cassette was placed in exon 11 in the 3' untranslated region of the X-linked forkhead box P3 (Foxp3) gene, without disrupting expression of the endogenous gene in this mutant mouse line. FOXP3 is a transcription factor necessary for the development and function of regulatory T (T reg) cells, which are required for suppression of self-reactive T cells and prevention of some autoimmune diseases. In these mice, EGFP expression is evident in FOXP3+ Treg cells. Homozygous Foxp3GFP mice are viable and fertile.

This new model from Dr Bernard Malissen of Centre d'Immunologie de Marseille-Luminy, France, targets the IRES-GFP cassette to exon 11, downstream of the endogenous Foxp3 STOP codon with no defects in FOXP3 or regulatory T cell function observed. This strain serves as an alternative to B6.Cg-Foxp3^tm2Tch/J (Stock No. 006772) which targets the IRES-GFP cassette in intron 9 of the coding region.

Development

The targeting vector was designed to insert (from 5' to 3') an internal ribosomal entry site (IRES) fused to an enhanced green fluorescent protein (EGFP) and a self-excising loxP-flanked ACN cassette into exon 11 of the X-linked forkhead box P3 (Foxp3) gene. The ACN cassette contained a neomycin resistance (Neo) gene and a testes-specific angiotensin-converting enzyme promoter-driven Cre recombinase gene (tACE-Cre). The construct was electroporated into C57BL/6-derived Bruce-4 embryonic stem (ES) cells. Correctly targeted ES cells were injected into FVB/N blastocysts and chimeric males were bred to C57BL/6J females. The donating investigator reported that the resulting Foxp3GFP mice were maintained on a C57BL/6J background (see SNP note below). Upon arrival mice at The Jackson Laboratory these mice were bred to C57BL/6J inbred mice (Stock No. 000664) for at least one generation to establish the colony.

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, all 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 C57BL/6N genetic background.

 

Allele

Symbol: Foxp3^tm1.1Mal
Name: targeted mutation 1.1, Bernard Malissen
MGI accession ID: MGI:3773675
Generation method: Targeted
Attributes: Reporter
Marker symbol: Foxp3
Marker name: forkhead box P3
Chromosome: X
Strain of origin: B6.Cg-Thy1^a
Expressed genes: GFP,Green Fluorescent Protein,; Foxp3,forkhead box P3,mouse, laboratory
Site of expression: EGFP expression is observed in FOXP3+ regulatory T cells.
Molecular note: The following sequences were inserted in the 3' UTR in exon 11: an IRES, the human diphtheria toxin receptor (HBEGF) cDNA coding region in-frame with the EGFP gene coding region, a loxP site, the mouse Ace (angiotensin I converting enzyme (peptidyl-dipeptidase A) 1) promoter, the cre recombinase gene, a neomycin resistance gene cassette, and a second loxP site. Cre-mediated self-excision removed the cre+neo cassette in the male germline. The presence of the EGFP cassette does not interfeer with expression of the gene locus. EGFP expression occurs in Foxp3⁺ regulatory T cells.