C.129-Il4^tm1Lky/J

Stock number: 004190
Product name: IL-4/GFP-enhanced transcript (4Get)
Research areas: Cancer Research, Immunology, Inflammation and Autoimmunity Research, Research Tools

Description

The "IL-4/GFP-enhanced transcript" (4Get) allele has a bicistronic IRES-EGFP reporter cassette inserted between the translational stop codon and the 3' UTR of the interleukin 4 gene (Il4); thus expressing the endogenous gene and EGFP. These 4Get mice have fluorescent reporter expression in IL-4-expressing cells, and may be useful for in vivo tracking of both innate and adaptive immune cells, and/or enabling their isolation without further stimulation.

Detailed description

Mice homozygous for the "IL-4/GFP-enhanced transcript" (4Get) targeted allele are viable, fertile, normal in size and do not display any gross physical or behavioral abnormalities. A knockin replaces the endogenous gene with an Il4/IRES/EGFP gene (IL4 activity remains intact). This leads to generation of a bicistronic transcript under the control of endogenous regulatory elements. Cells activated to express IL4 will express EGFP, allowing reliable in vivo tracking of both innate and adaptive immune cells, and/or enabling their isolation without further stimulation. As the IRES element promotes translational competence capable of revealing low-level transcription otherwise not apparent from the canonical 5'-cap of the mRNA, cells from these mice can also be used to report competence for IL4 production upon stimulation.

Development

A targeting vector was designed with a loxP-flanked neomycin resistance cassette, an internal ribosome entry site (IRES), a green fluorescent protein gene, and bovine growth hormone polyadenylation signal. The targeting vector was inserted between the endogenous translational stop codon and the 3' UTR in exon 4 of the interleukin 4 gene (Il4) via electroporation into 129S4/SvJae-derived PrmCre embryonic stem (ES) cells. These PrmCre ES cells contain the Prm-cre transgene with the protamine promoter directing cre expression to the male germline. Correctly targeted ES cells were injected into recipient blastocysts. Chimeric males were bred to BALB/cAnNCrlBR females. The male offspring from this initial breeding lack the floxed neo cassette in their germline, and were bred to female BALB/cAnNCrlBR mice. Offspring with the IRES-EGFP reporter cassette and without the Pmc-Cre transgene were identified to establish the colony of "IL-4/GFP-enhanced transcript" (4Get) mice. These 4Get mice were subsequently backcrossed to BALB/cAnNCrlBR mice for at least five generations prior to sending to The Jackson Laboratory Repository in 2002. Upon arrival, the colony was maintained by breeding mutant mice together. In 2007, the colony was bred to BALB/cJ inbred mice (Stock No. 000651) for at least one generation, and thereafter maintained by breeding mutant mice together.



In 2019 a 48 SNP (single nucleotide polymorphism) panel analysis, with 43 markers covering all 19 chromosomes and the X chromosome was performed on the rederived living colony at The Jackson Laboratory Repository. Two markers that determine BALB/c substrain, on Chromosomes 7 and 14, were found to be segregating.

Allele

Symbol: Il4^tm1Lky
Name: targeted mutation 1, Richard M Locksley
MGI accession ID: MGI:2176574
Generation method: Targeted
Attributes: Reporter
Marker symbol: Il4
Marker name: interleukin 4
Chromosome: 11
Strain of origin: Not Specified
Expressed genes: GFP,Green Fluorescent Protein,
Site of expression: Cells activated to express IL-4 will express GFP. IL-4 activity remains intact.
Molecular note: A loxP-flanked neomycin cassette followed by an internal ribosomal entry site (IRES) and an EGFP gene was inserted into sequences corresponding to the 3' untranslated region in exon 4. The neomycin cassette was removed by Cre mediated germline recombination in chimeric mice to generate the final allele. These mice express green fluorescent protein under the control of the Il4 promoter.