NOD.129X1(Cg)-Foxp3^tm2Tch/DvsJ

Stock number: 025097
Product name: Foxp3^EGFP

Description

These "Foxp3EGFP" mice co-express EGFP and the regulatory T cell-specific transcription factor Foxp3, with expression of EGFP restricted to the T cell lineage, primarily to the CD4+ T reg cell population. On the congenic NOD background these mutant mice exhibit a diabetes incidence similar to NOD inbred mice. These mutant mice may be useful in immunological studies, including studies of regulatory T cell proliferation, localization, and antigen independence during the primary immune response.

Detailed description

Homozygous mice are viable and fertile with normal T and B cell development. These "Foxp3^EGFP" mice co-express EGFP and the regulatory T cell-specific transcription factor Foxp3 under the control of the endogenous promoter. EGFP expression accurately identifies the Foxp3⁺ T cell population (more than 97% of Foxp3⁺ T cells were EGFP⁺), and Foxp3 mRNA expression strictly segregates with EGFP⁺ T cells. Due to X-inactivation in females, when the reporter construct in a heterozygous not a homozygous state, the number of EGFP⁺CD4⁺ T cells found in the peripheral blood of heterozygous females was approximately half that of hemizygote males. CD4⁺EGFP⁺ cells also exhibit normal regulatory T cell suppression of effector cell proliferation (following stimulation with anti-CD3 and anti-CD28 monclonal antibodies ). Some EGFP expression is noted in a small population of CD8⁺ thymocytes. These mutant mice may be useful in immunological studies, including studies of regulatory T cell proliferation, localization, and antigen independence during the primary immune response. On the congenic NOD background these mutant mice exhibit a diabetes incidence similar to NOD inbred mice.

This strain targets the GFP cassette downstream of the endogenous Foxp3 STOP codon with no defects in Foxp3 or regulatory T cell function observed.

In an attempt to offer alleles on well-characterized or multiple genetic backgrounds, alleles are frequently moved to a genetic background different from that on which an allele was first characterized. This allele was originally published on a BALB/c genetic background (see Stock No. 006769). It should be noted that the phenotype could vary from that originally described. The strain description will be modified as published results become available.

Development

A targeting vector was designed to place an IRES-EGFP-SV40 polyA sequence immediately downstream of the endogenous Foxp3 translational stop codon but upstream of the endogenous polyA signal. This also placed a loxP-flanked PGKneo cassette into intron 9. This vector was electroporated into 129X1Sv/J-derived SCC10 embryonic stem (ES) cells. Correctly targeted ES cells were injected into C57BL/6 blastocysts and chimeric males were mated with C57BL/6 females. The PGKneo cassette was removed by mating founder males with Cre-deleter female mice on a C57BL/6 congenic background. The resulting mice (now harboring this Foxp3EGFP allele) were maintained on a B6 background prior to 18 backcross generations to NOD/ShiLtDvs. Upon transfer to The Jackson Laboratory Repository, the mice were crossed to NOD/ShiLtJ (Stock No. 001976) at least once to establish the colony.

Allele

Symbol: Foxp3^tm2Tch
Name: targeted mutation 2, Talal A Chatila
MGI accession ID: MGI:3699400
Generation method: Targeted
Attributes: Reporter
Synonyms: Foxp3^tm2(EGFP)Tch; Foxp3^EGFP; Foxp3^IRES-GFP; Foxp3-GFP KI; FoxP3.GFP
Marker symbol: Foxp3
Marker name: forkhead box P3
Chromosome: X
Strain of origin: 129X1/SvJ
Expressed genes: GFP,Green Fluorescent Protein,
Site of expression: EGFP is expressed in the Foxp3⁺ T cell population. Some EGFP expression is noted in a small population of CD8⁺ thymocytes.
Molecular note: An IRES-EGFP-SV40 poly A sequence was inserted immediately downstream of the endogenous Foxp3 translational stop codon, but upstream of the endogenous polyA signal, generating a bicistronic locus encoding both Foxp3 and EGFP. Expression of EGFP is restricted to the T cell lineage, primarily to the CD4+ T cell population.