C.Cg-Klrk1^tm1Dhr Klra8^Cmv1-r/DhrJ

Stock number: 025661
Research areas: Apoptosis Research, Cancer Research, Immunology, Inflammation and Autoimmunity Research, Research Tools, Virology Research

Description

These Klrk1 knock-out mice exhibit subtle changes in the expression of certain NK cell regulatory molecules. They are suitable for use in applications related to the study of NK cell-mediated lysis.

Detailed description

Exons 1b-6 of the killer cell lectin-like receptor subfamily K, member 1 (Klrk1) gene have been removed in these Klrk1^-/- mice, abolishing gene expression. Klrk1 encodes NKG2D, a stimulatory immunoreceptor expressed by natural killer (NK) cells, activated CD8 T cells, certain CD4⁺ T cells, and subsets of gamma/delta and NK1.1⁺ T cells. NKG2D ligands are expressed during times of cellular stress, leaving cells susceptible to NK cell mediated lysis. As such, NKG2D has been associated with tumor surveillance, pathogen immunity, autoimmunity, and graft rejection.

These mice were backcrossed to C.B6-Klra8^Cmv1-r/UwaJ mice (Stock No. 002936), and subsequently contain C57BL/6-derived genes, including killer cell lectin-like receptor, subfamily A (Klra), killer cell lectin-like receptor subfamily B member 1 (Klrb1) and killer cell lectin-like receptor, subfamily A, member 8 (Klra8), on a BALB/c background. This strain is useful in tumor models involving NK cell regulation and the expression of NK1.1. On a BALB/c background, these mice carry the H-2^d haplotype known to react more strongly with NK cell Ly49 inhibitory receptors.

These BALB.B6-Cmv1^r Klrk1^-/- mice contain significantly reduced numbers of Ly49G2+ and Ly49F+ NK cells in spleen and bone marrow. They also had an increase in the percentage of terminally mature CD27^lo NK cells and greater functional responses to stimulation with NK1.1, Ly49D, and NKp46 antibodies or to cytokines. Subtle changes in expression of certain NK markers, including Ly49 receptors, were observed in the mutant mice. Klrk1^+/- mice show a partial reduction in cell-surface expression of NKG2D, compared to wildtype mice, and exhibit some partial functional phenotypes. Homozygotes are viable and fertile.

In an attempt to offer alleles on well-characterized or multiple genetic backgrounds, alleles are frequently moved to a genetic background different from that on which an allele was first characterized. It should be noted that the phenotype could vary from that originally described. We will modify the strain description if necessary as published results become available.

Development

A targeting vector was designed to replace exons 1b-6 of the killer cell lectin-like receptor subfamily K, member 1 (Klrk1) gene with a loxP-flanked neomycin resistance (neo) cassette. The construct was electroporated into C57BL/6-derived Bruce-4 embryonic stem (ES) cells. Correctly targeted ES cells were injected into BALB/c blastocysts and resulting chimeric males were bred to C57BL/6J females. Heterozygous offspring were bred with CMV-Cre transgenic mice, on a congenic C57BL/6J background, to delete the neo cassette. Progeny were crossed to C57BL/6J remove the Cre-expressing transgene. These mice were bred to C57BL/6J mice for at least 3 generations, and subsequently to C.B6-Klra8^Cmv1-r/UwaJ mice (Stock No. 002936) for at least 10 generations. Upon arrival, mice were bred to BALB/cJ inbred mice (Stock No. 000651) for at least one generation to establish the colony.

Allele

Symbol: Klra8^Cmv1-r
Name: cytomegalovirus resistance 1, resistant
MGI accession ID: MGI:2387148
Generation method: Not Applicable
Marker symbol: Klra8
Marker name: killer cell lectin-like receptor, subfamily A, member 8
Chromosome: 6
Strain of origin: C57BL/6
Molecular note: Mapping experiments confirmed that the C57BL/6 strain contained the Klra8 gene, and expression of Klra8 correlated with the resistant phenotype.

Allele

Symbol: Klrk1^tm1Dhr
Name: targeted mutation 1, David H Raulet
MGI accession ID: MGI:3790957
Generation method: Targeted
Attributes: Null/Knockout
Marker symbol: Klrk1
Marker name: killer cell lectin-like receptor subfamily K, member 1
Chromosome: 6
Strain of origin: B6.Cg-Thy1^a
Molecular note: Exons 1b through exon 6 were replaced by a floxed neomycin resistance cassette through homologous recombination. Mice carrying germline mutations were crossed with a cre transgenic mouse strain to remove the neomycin selection cassette, leaving a single loxP site behind. Gene inactivation was confirmed by a lack of protein staining on NK cells using flow cytometry.