C.129S4(B6)-Il12b^tm2.1Lky/J

Stock number: 015863
Research areas: Cell Biology Research, Immunology, Inflammation and Autoimmunity Research, Research Tools

Description

A targeting vector was designed to insert an internal ribosome entry site (IRES)-enhanced green fluorescent protein (eGFP) fusion protein, followed by a floxed neomycin (neo) resistance cassette, downstream of the endogenous translational stop codon of the interleukin 12b (Il12b) gene. These mice may be useful for visualizing active IL-12 in DCs and macrophages during immune response.

Detailed description

A targeting vector was designed to insert an internal ribosome entry site (IRES)-enhanced green fluorescent protein (eGFP) fusion protein, followed by a floxed neomycin (neo) resistance cassette, downstream of the endogenous translational stop codon of the interleukin 12b (Il12b) gene. These homozygous GET40 mice are viable, fertile, and normal in size. IL-12b, or p40, binds with p35 to form the heterodimeric cytokine IL-12, after induction by toll like receptors (TLRs), in macrophages and dendritic cells (DC). GET40 mice show p40 and GFP expression in DC in draining lymph nodes, after inoculation with Listeria monocytogenes or lipopolysaccharide (LPS), and promote Th1 differentiation. These mice may be useful for visualizing active IL-12 in DCs and macrophages during immune response.

Development

A targeting vector was designed to insert an internal ribosome entry site (IRES)-enhanced green fluorescent protein (eGFP) fusion protein, followed by a floxed neomycin (neo) resistance cassette, downstream of the endogenous translational stop codon of the interleukin 12b (Il12b) gene. The construct was electroporated into 129S4/SvJae-derived PC3 embryonic stem (ES) cells. These PC3 cells contain a transgene expressing Cre recombinase under control of the protamine promoter (Tg(Prm-cre)700g), to delete the neo cassette in the male germline. Correctly targeted ES cells were injected into C57BL/6 blastocysts and the resulting chimeric males were bred to C57BL/6 females. The male offspring from this initial breeding lack the floxed neo cassette and were bred to female C57BL/6 mice to establish a colony of GET40 mice. These mutant mice were backcrossed to BALB/cJ mice for at least 10 generations. Upon arrival at The Jackson Laboratory, mice were bred to BALB/cJ (Stock No. 000651) for at least one generation.

Allele

Symbol: Il12b^tm2.1Lky
Name: targeted mutation 2.1, Richard M Locksley
MGI accession ID: MGI:3663352
Generation method: Targeted
Attributes: Reporter
Marker symbol: Il12b
Marker name: interleukin 12b
Chromosome: 11
Strain of origin: 129S4/SvJae-Tg(Prm-cre)70Og
Expressed genes: GFP,Green Fluorescent Protein,
Site of expression: GFP and Il12b are expressed in dendritic cells of draining lymph nodes after inoculation with Listeria monocytogenes or lipopolysaccharide.
Molecular note: A targeting vector was designed to insert an internal ribosomal entry site (IRES)-enhanced green fluorescent protein (EGFP; Clontech) sequence (followed by a bovine growth hormone poly(A) signal and a loxP site flanked neomycin resistance gene cassette) downstream of the stop codon in exon 8 of the endogenous gene. The construct was electroporated into ES cells that contain the Tg(Prm-cre)70Og transgene that effects the removal of the neo cassette through cre-mediated recombination in the male germline.