B6.129(Cg)-Foxp3^{tm3(HBEGF/GFP)Ayr}/J

Stock number: 016958
Product name: Foxp3^DTR
Research areas: Immunology, Inflammation and Autoimmunity Research, Research Tools

Description

Foxp3^DTR knock-in mice express the human diphtheria toxin receptor (designated heparin-binding EGF-like growth factor [HBEGF]) and EGFP genes from the Foxp3 locus--without disrupting expression of the endogenous Foxp3 gene. These mice may be useful for regulatory T cell visualizing and ablation.

Detailed description

Foxp3^DTR knock-in mice contain an internal ribosome entry site (IRES), a human diphtheria toxin receptor (DTR, designated heparin-binding EGF-like growth factor [HBEGF]), and an enhanced green fluorescent protein (EGFP) downstream of the internal stop codon of the X-linked forkhead box P3 (Foxp3) gene. FOXP3 is a transcription factor required 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, DTR-EGFP expression is evident in FOXP3⁺ T_reg cells. Diphtheria toxin (DT) administration results in ablation of T_reg cells in thymus, lymph nodes, and spleen 2 days after injection, with cell numbers rebounding 10-15 days post-injection. Neonates injected with DT daily all die from lymphoproliferative disease, indicated by failure to thrive, lack of mobility, ventral skin lesions, hunched posture, and conjunctivitis, within 27 days of birth. With the same DT treatment, adults exhibit a more rapid development of autoimmune disease and die within 3 weeks. These mice show an increase in CD4⁺ T cell activation, as well as an increase in the number of B cells, macrophages, granulocytes, natural killer, and dendritic cells in the spleen and lymph nodes. Homozygous females and hemizygous males are viable, fertile, and normal in size. These mice may be useful for visualizing and specifically eliminating regulatory T cells, and for studying autoimmunity and immune dysfunction.

Development

The Foxp3^DTR targeting vector was designed with an internal ribosome entry site (IRES), a human diphtheria toxin receptor (DTR, designated heparin-binding EGF-like growth factor [HBEGF]), and an enhanced green fluorescent protein (EGFP), followed by a frt-flanked neomycin (neo) resistance cassette inserted downstream of the internal stop codon of the X-linked forkhead box P3 (Foxp3) gene. This construct was injected into (129X1/SvJ x 129S1/Sv)F1-Kitl⁺-derived R1 embryonic stem (ES) cells. Correctly targeted ES cells were injected into C57BL/6 blastocysts. The donating investigator reported that the resulting mice were backcrossed to C57BL/6NTac mice for at least 8 generations (see SNP note below). Upon arrival at The Jackson Laboratory, mice were bred to C57BL/6NJ inbred mice (Stock No. 005304) for at least one generation.

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/6 genetic background.

Allele

Symbol: Foxp3^{tm3(HBEGF/GFP)Ayr}
Name: targeted mutation 3, Alexander Y Rudensky
MGI accession ID: MGI:3698131
Generation method: Targeted
Attributes: Reporter; Inserted expressed sequence
Synonyms: Foxp3^DTR; Foxp3^{tm3(DTR/GFP)Ayr}; Foxp3^tm3Ayr; Foxp3-DTR; Foxp3-GFP; Foxp3-IRES-DTR-GFP KI (FDG)
Marker symbol: Foxp3
Marker name: forkhead box P3
Marker synonyms: AIID; DIETER; IPEX; JM2; PIDX; RGD1562112; scurfin; XPID
Chromosome: X
Strain of origin: (129X1/SvJ x 129S1/Sv)F1-Kitl⁺
Expressed genes: DTR/EGFP,Simian Diphtheria Toxin Receptor; Enhanced Green Fluorescent Protein,
Site of expression: DTR-EGFP expression is evident in regulatory T cells.
Molecular note: A targeting vector was designed to insert a cDNA encoding the human diphtheria toxin receptor (HBEGF/DTR) fused to sequences encoding a green fluorescent protein (GFP) equipped with an internal ribosome entery (IRES), IRES-DTR-GFP with a floxed neo into the 3' untranslated region downstream of exon 11 of the Foxp3 gene.