C57BL/6-Il22^{tm1.1(icre)Stck}/J

Stock number: 027524
Product name: IL22^Cre
Research areas: Immunology, Inflammation and Autoimmunity Research, Research Tools

Description

IL22^Cre knock-out/in mice express Cre recombinase in a subset of lymphoid cells including group 3 innate lymphoid cells in the gut and γδ T cells in skin or lung.

Detailed description

IL22^Cre mice have a codon optimized Cre Recombinase (iCre), replacing exon 1 of the Il22 (interleukin 22) gene. The presence of iCre abolishes expression of IL-22. IL-22 is a cytokine expressed by immune cells that is required for immune responses to bacterial infections. Homozygous mice are viable and fertile. 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 bred to mice containing a cre-inducible fluorophore, mice serve as a fate reporter that marks cells that had initiated the IL-22 program. Under steady state conditions, iCre expression is restricted to group 3 innate lymphoid cells (ILC3) in the gut and γδ T cells in skin or lung. γδ and CD4 T cells expand in the skin when used as a model of psoriasiform inflammation induced by the TLR7 ligand, imiquimod. An expansion of CD4 T cells, which were induced in innate lymphoid follicles in the colon, was evident during Citrobacter rodentium infection. Homozygous IL-22 deficient mice fail to clear the infection and succumb to the infection by day 8.

Development

A targeting construct was designed to replace exon 1 of the Il22 (interleukin 22) gene with a 6 aa linker sequence, a codon improved Cre Recombinase gene (iCre) followed by an SV40 polyadenylation sequence, and a frt-flanked neomycin resistance (neo) cassette. This construct was electroporated into C57BL/6N-derived embryonic stem (ES) cells. Correctly targeted ES cells were injected into blastocysts and the resulting chimeric males were bred to FLPe mice on a C57BL/6-NIMR background to remove the neo cassette. These IL22^Cre mice were backcrossed for at least 3 generations to C57BL/6-NIMR mice. Upon arrival at The Jackson Laboratory, mice were bred to C57BL/6J inbred mice (Stock No. 000664) for at least one generation to establish the colony.

In 2017, 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. One of the 5 markers that determine C57BL/6J from C57BL/6N was found to be segregating on Chromosome 8. These data suggest the mice sent to The Jackson Laboratory Repository were on a mixed C57BL/6N;C57BL/6J genetic background.

Allele

Symbol: Il22^{tm1.1(icre)Stck}
Name: targeted mutation 1.1, Brigitta Stockinger
MGI accession ID: MGI:5632146
Generation method: Targeted
Attributes: Recombinase-expressing
Marker symbol: Il22
Marker name: interleukin 22
Chromosome: 10
Strain of origin: C57BL/6N
Expressed genes: cre,cre recombinase,bacteriophage P1
Site of expression: Cre expression is restricted to group 3 innate lymphoid cells in the gut and gamma/delta T cells in skin or lung.
Molecular note: A targeting construct was designed to replace exon 1 of the Il22 (interleukin 22) gene with a 6 aa linker sequence, a codon improved Cre Recombinase gene (iCre) followed by an SV40 polyadenylation sequence and a FRT-flanked neomycin resistance (neo) cassette. Flp-mediated recombination removed the FRT-flanked neo cassette.