B6.Cg-Rag2^tm1.1Cgn/J

Stock number: 008449
Product name: RAG2 KO
Research areas: Developmental Biology Research, Hematological Research, Immunology, Inflammation and Autoimmunity Research, Internal/Organ Research, Research Tools, Virology Research

Description

RAG2 knock-out mice produce no mature T cells or B cells. Their phenotype can be described as a "non-leaky" immune deficiency. These mice may be useful in the study of hematopoietic and immune system defects, cancer, toxicology, and xenograft/transplant studies.

Of note, a C57BL/6J isogenic Rag2 knock-out strain is also available as Stock No. 033526.

Detailed description

The Rag2 gene is critical for (V(D)J) recombination in the process of B and T cell maturation. The RAG2 knock-out allele (also called RAG-2^del) has exon 3 (which contains the entire RAG-2 protein coding region) deleted by Cre-mediated excision. Homozygous mice are viable and fertile and may be expected to have the same knockout phenotype as other RAG-2 null mutants or similarly created RAG-2 exon 3 pan-deleted mutants; with hematopoietic and immune system defects including arrested B cell and T cell development at the pro-B and the pro-T cell stages, respectively. Whereas Prkdc^scid homozygotes produce some B cells and IgM (i.e., are "leaky"), RAG-2^del homozygotes lack all mature lymphocytes (i.e., are "non-leaky") and do not have an increased sensitivity to irradiation or genotoxic drugs. These RAG-2^del mice may be useful in studying cancer and toxicology (as a xenograft/transplant host), hematopoiesis, hematology, immunology, and inflammation research.

Development

A targeting vector was designed to insert a loxP-flanked neomycin resistance gene on one side, and a third loxP site on the other side of exon 3 of the recombination activating gene 2 (Rag2) locus. This construct was electroporated into B6.Cg-Thy1^a-derived Bruce-4 embryonic stem (ES) cells. Correctly targeted ES cells were transiently transfected with a cre-expressing vector to remove the selection cassette. ES cells in which the neomycin resistance cassette was deleted (leaving a single loxP site upstream, and a single loxP downstream of exon 3) were injected into recipient blastocysts. Chimeric males were bred with C57BL/6 females to generate RAG-2^fl mice. The RAG-2^fl mice were bred with transgenic mice on mixed genetic background, and then bred with mutant mice on a C57BL/6 genetic background for 8 generations. The donating investigator reports that both the transgene and other mutant gene were bred out of the RAG-2^fl mice prior to arrival at The Jackson Laboratory (as Stock No. 008309). Upon arrival, some RAG-2^fl males were bred to cre-deleter females (Zp3-Cre transgenic mice on a C57BL/6 genetic background; Stock No. 003651), and then F1 males were bred back to B6.Zp3-Cre females. The resulting RAG-2^del (exon 3 deleted) offspring were bred to C57BL/6J inbred mice (selecting for the RAG-2^del mutation and against the cre transgene) for at least 1 generation to generate this RAG-2 "knockout" strain (Stock No. 008449).

A SNP (single nucleotide polymorphism) panel analysis, with 27-48 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 living colony at The Jackson Laboratory Repository. By the end of 2015 (generation N9+N4) up to present (February 2022), all tested cohorts have shown markers to be C57BL/6J allele-type.

Allele

Symbol: Rag2^tm1.1Cgn
Name: targeted mutation 1.1, University of Cologne
MGI accession ID: MGI:2654909
Generation method: Targeted
Attributes: Null/Knockout
Marker symbol: Rag2
Marker name: recombination activating gene 2
Chromosome: 2
Strain of origin: B6.Cg-Thy1^a
Molecular note: This allele is a derivative of Rag2^tm1Cgn in which the sequences flanked by loxP sites were deleted in vivo by crossing mice carrying this allele to a deleter strain.