C.Cg-Foxp3^tm2Tch/J

Stock number: 006769
Product name: Foxp3^EGFP
Strain synonyms: FoxP3.GFP, Foxp3-GFP KI, Foxp3^IRES-GFP
Research areas: Immunology, Inflammation and Autoimmunity Research, Research Tools

Description

These "Foxp3EGFP" mice co-express EGFP and the regulatory T cell-specific transcription factor Foxp3 under the control of the endogenous promoter. 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 "Foxp3EGFP" 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, the number of EGFP⁺ CD4⁺ T cells found in the peripheral blood of heterozygous females was approximately half that of hemizygous males. CD4⁺ EGFP⁺ cells also exhibit normal regulatory T cell suppression of effector cell proliferation (following stimulation with anti-CD3 and anti-CD28 monoclonal 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.

This allele is also on a C57BL/6 genetic background (see Stock No. 006772).

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. The construct also introduced 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 BALB/c females. The PGKneo cassette was removed by mating founder males with Cre-deleter female mice on a BALB/c congenic background. The resulting mice (now harboring this Foxp3^EGFP allele) were then backcrossed for 8 generations to BALB/cAnNTac inbred mice prior to arrival at The Jackson Laboratory. During the importation process, this strain may have been bred with BALB/cJ inbred mice (Stock No. 000651) for at least one generation.

Allele

Symbol: Foxp3^tm2Tch
Name: targeted mutation 2, Talal A Chatila
MGI accession ID: MGI:3699400
Generation method: Targeted
Attributes: Reporter
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.