B6.129P2-Cxcr6^tm1Litt/J

Stock number: 005693
Product name: Bonzo KO
Research areas: Immunology, Inflammation and Autoimmunity Research, Research Tools

Description

In this targeted reporter strain, the Cxcr6 coding region was replaced by EGFP cDNA. EGFP is expressed on liver leukocytes, but is not seen on other leukocytes like macrophages and neutrophils. EGFP expression is seen on natural killer T (NKT) cells of the liver. This mutant may be useful in studies of hepatitis, human and simian immunodeficiency viruses (HIV and SIV), fluorescent T cell tracking, and various immune responses.

Detailed description

Mice homozygous for this EGFP "knock-in" are viable, fertile, normal in size, and do not display any behavioral abnormalities when maintained under barrier conditions. Lymph nodes and spleen show no endogenous gene expression. Lymphocytes from heterozygotes, but not homozygotes, show endogenous ligand binding. EGFP is expressed in cell subsets similar to human Bonzo/STRL33, namely in T cells, particularly those displaying markers of effector/memory cells and those stimulated by IL-2.

CXCR6-deficient mice exhibit a reduction of CD1d-reactive NKT cells in the liver and decreased susceptibility to T-cell-dependent hepatitis. They are protected from liver fibrosis; macrophage infiltration and protein levels of inflammatory cytokines IFN-gamma, TNF-alpha, and IL-4 are reduced in fibrotic livers of Cxcr6^-/- mice. Liver and lung NKT cells are depleted in homozygous and heterozygous Cxcr6^tm1Litt mice.

Metastasis of LLC and B16 tumor cells to the liver is enhanced in Cxcr6^-/- mice. This mutant may be useful in studies of hepatitis, HIV, SIV, fluorescent T cell tracking, and various immune responses.

Development

A targeting vector containing an enhanced green fluorescent protein (EGFP, Clonetech)/SV40 poly(A)n cassette with a downstream loxP-flanked neomycin resistance gene and herpes simplex virus thymidine kinase was used to replace the endogenous coding sequence. The construct was electroporated into the 129P2/OlaHsd-derived E14 embryonic stem (ES) cells. Correctly targeted ES cells were transiently transfected with a Cre recombinase-expressing vector before being injected into C57BL/6 blastocysts. The resulting chimeric mice were bred to C57BL/6 mice. The donating investigator stated that heterozygotes were backcrossed to C57BL/6 mice (see SNP note below) for 13 generations before being made homozygous.

In 2021, 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. THis marker encodes the rd8 recessive mutation associated with retinal degeneration on Chromosome 1 within the Crb1 locus. These data suggest the mice sent to The Jackson Laboratory Repository were on a mixed C57BL/6N;C57BL/6J genetic background.

Allele

Symbol: Cxcr6^tm1Litt
Name: targeted mutation 1, Daniel Littman
MGI accession ID: MGI:3613526
Generation method: Targeted
Attributes: Reporter; Null/Knockout
Marker symbol: Cxcr6
Marker name: chemokine (C-X-C motif) receptor 6
Chromosome: 9
Strain of origin: 129P2/OlaHsd
Expressed genes: GFP,Green Fluorescent Protein,
Site of expression: EGFP expression mimics endogenous gene expression and is detected in the spleen and lymph nodes, specifically activated/memory T cells.
Molecular note: The coding sequence was replaced with an EGFP. RT-PCR failed to detect transcript in mutants. Strong GFP expression was detected in spleen and lymphoid nodes.