B6(C)-Il5^{tm1.1(icre)Lky}/J

Stock number: 030926
Product name: Red5, R5
Research areas: Research Tools

Description

Red5/R5 targeted knock-in/knock-out mice express tdTomato and humanized Cre recombinase from the mouse Il5 promoter in a variety of tissues.

Detailed description

Red5/R5 targeted knock-in/knock-out mutant mice express tdTomato fluorescent reporter and mammalian-optimized huCre recombinase from the mouse Il5 (interleukin 5) promoter. Endogenous expression of Il5 is knocked out. Expression of tdTomato and huCre from the Il5 promoter are faithful to normal patterns.

tdTomato reporter expression has been examined by flow cytometry, immunofluorescence microscopy, confocal microscopy, and multi-photon microscopy. CD45⁺ R5⁺ CD4^- cells are present in non-lymphoid tissues, including the brain, heart, lung, kidney, skin, intestine and uterus, whereas few R5⁺ cells are in lymphoid organs, including spleen, bone marrow, lymph nodes or thymus, or in the liver. In all tissues, the vast majority of R5⁺ cells are small cells that lack lineage markers for T, B, natural killer (NK) and myeloid cells, and express markers for innate lymphoid type 2 cells (ILC2s).

Crosses with mice expressing B6.129P2-Gt(ROSA)26Sor^tm1(DTA)Lky/J (see Stock No. 009669) can be done to selectively delete cells expressing the mutant allele.

This strain has been useful in studying the source of Il5 in eosinophil homeostasis and ILC2 biology.

Development

Rabbit β-globin (partial exon 2-3 genomic sequence serving as an artificial intron and splicing donor/acceptor), tandem dimer red fluorescent protein (tdTomato), encephalomyocarditis virus (EMCV) internal ribosome entry site (IRES), huCre (P1 phage cre-recombinase cDNA optimized for human/mammalian cells), bovine growth hormone (bGH) poly-adenylation signal (pA), and a loxP-flanked neomycin cassette replace the translational initiation site of the mouse Il5 gene. The mutation was created via homologous recombination in C57BL/6J-derived PRX-B6T embryonic stem (ES) cells. The floxed neomycin cassette was excised by through crosses with CMV-cre mice (see Stock No. 006054). This strain was maintained on a C57BL/6J genetic background by the donating laboratory.

Allele

Symbol: Il5^{tm1.1(icre)Lky}
Name: targeted mutation 1.1, Richard M Locksley
MGI accession ID: MGI:5558083
Generation method: Targeted
Attributes: Recombinase-expressing; Reporter; Null/Knockout
Synonyms: Il5^R; Il5^Red5; R5; Il5^-
Marker symbol: Il5
Marker name: interleukin 5
Marker synonyms: EDF; Il-5; TRF
Chromosome: 11
Strain of origin: C57BL/6J
Expressed genes: cre,cre recombinase,bacteriophage P1; RFP,Red Fluorescent Protein,coral
Site of expression: Mice express tdTomato and cre in cells where Il5 is expressed.
Molecular note: A targeting vector with a cassette composed of, (from 5' to 3'), a partial rabbit beta-globin exon 2-3 genomic sequence, the tdTomato coding sequence, an internal ribosomal entry site (IRES), a humanized cre recombinase sequence and a bovine growth hormone polyadenlyation signal was flanked by Il5 homology arms and linearized for homologous recombination in ES cells. The cassette was inserted at the transcriptional start ATG codon of the Il5 gene. Chimeric males were crossed to CMV-cre females to excise the neo marker, and then male offspring were bred to wild-type B6 females to remove the CMV-cre from the background. Mice express tdTomato and cre in cells where Il5 is expressed.