STOCK Il2^{tm1.1(cre)Iwsh}/J

Stock number: 029619
Product name: IL-2^cre
Research areas: Immunology, Inflammation and Autoimmunity Research, Research Tools

Description

IL-2^cre knock-in mice express Cre recombinase under the direction of the IL-2 promoter. These mice are useful for labelling CD4⁺ T cells in lung, bone marrow, spleen, Peyer’s Patches, mesenteric lymph nodes, and intraepithelial lymphocytes and lamina propria of small intestine.

Detailed description

IL-2^cre knock-in/knock-out mice have a Cre-IRES fusion protein inserted upstream of the first codon of the interleukin 2 (Il2) gene. The presence of the IRES-Cre cassette upstream of the stop codon allows for expression of IL-2 and cre. IL-2 is a growth factor for activated T cells and is required for differentiation of activated naïve CD4 T cells into effector and memory CD4 T cells, and for maintenance of naturally arising regulatory T cells (nTregs). Homozygous IL-2^cre/cre mice develop a lymphoproliferative disorder similar to that observed in IL-2 knock-out mice, with over four times higher cell numbers in spleen than the control. They also exhibit a loss of CD4⁺CD25⁺ cells. When these mice are bred with mice containing loxP-flanked sequence, Cre-mediated recombination will result in deletion of the floxed sequences in the Cre-expressing cells of the offspring.

When IL-2^cre mice are bred to B6.129(Cg)-Tg(CAG-Bgeo/GFP)21Lbe/J mice (Stock No. 004178),resulting offspring express EGFP in intraepithelial lymphocyte and lamina propria, as well as bone marrow, mesenteric lymph nodes, and Peyer's patches 5 days after birth. These cells also produce IL-10 and IFN-γ.

Development

A targeting construct was designed to insert (from 5’ to 3’) a Cre Recombinase sequence, a frt-flanked neomycin resistance (neo) cassette, in opposite orientation to the gene, and an internal ribosomal entry site (IRES) upstream of the first codon of the interleukin 2 (Il2) gene. This construct was electroporated into C57BL/6-derived embryonic stem (ES) cells. Correctly targeted ES cells were injected into blastocysts and the resulting chimeric males were bred to Actin-FLPe females (on a C57BL/6 congenic background) to remove the neo cassette. Offspring were crossed to remove the flp-expessing transgene, and resulting IL-2^cre mice were bred to C57BL/6J mice for at least 7 generations. Upon arrival, sperm was cryopreserved. To establish our live colony, an aliquot of frozen sperm was used to fertilize C57BL/6J oocytes (Stock No. 000664).

A 48 SNP (single nucleotide polymorphism) panel analysis, with 43 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. Three of the 43 markers throughout the genome were segregating, suggesting an incomplete backcross. Also, 4 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: Il2^{tm1.1(cre)Iwsh}
Name: targeted mutation 1.1, Makio Iwashima
MGI accession ID: MGI:5804692
Generation method: Targeted
Attributes: Recombinase-expressing
Synonyms: il-2^cre
Marker symbol: Il2
Marker name: interleukin 2
Marker synonyms: IL-2; lymphokine; TCGF
Chromosome: 3
Strain of origin: C57BL/6
Expressed genes: cre,cre recombinase,bacteriophage P1; Il2,interleukin 2,mouse, laboratory
Site of expression: When these mice are bred with mice containing loxP-flanked sequence, Cre-mediated recombination will result in deletion of the floxed sequences in the Cre-expressing cells of the offspring.
Molecular note: A targeting vector was designed to insert a cre recombinase cDNA, an frt-flanked neo cassette, and an internal ribosome entry site (IRES) into the Il2 gene just upstream of the first codon. The mice with correct targeted inserts were bred with Actin-FLPe females (on a C57BL/6 congenic background) to remove the neo selection cassette.