B6.Cg-Igk-J^tm1Dim Igh-J^tm1Dim H2^g7/J

Stock number: 035273
Product name: 121, H¹²¹ L¹²¹
Strain synonyms: 121
Research areas: Immunology, Inflammation and Autoimmunity Research, Mouse/Human Gene Homologs

Description

H¹²¹ L¹²¹ (121) mice carry antigen specific B cell receptors with a high affinity for glucose-6-phosphate isomerase (GPI) and the diabetogenic H2^g7 haplotype. GPI functions as an autoantigen associated inflammatory rheumatoid arthritis.

Detailed description

H¹²¹ L¹²¹ (121) mice carry rearranged V_HD_HJ_H and V_LJ_L sequence (respectively) from the anti-GPI mAb 6.121 derived from a mouse model of inflammatory rheumatoid arthritis, K/BxN (Tg(TcraR28,TcrbR28)KRNDimxNODF1). mAb 6.121 is an IgG1 mAb that has a high binding affinity for glucose-6-phosphate isomerase (GPI), a widely expressed blood borne enzyme and the target autoantigen in the K/BXN model. In addition, 121 mice carry the diabetogenic H2^g7 haplotype. A high fraction of B cells from 121 mice are reactive to GPI self-antigen, specifically, the bone marrow has an increase in immature B cells and proportionate decrease in mature B cells, as well as increased IgG (anti-GPI) and IgM (anti-GPI). Triple homozygotes have a higher percentage of autoreactive B cells than heterozygotes. H¹²¹ L¹²¹ (121) mice do not develop arthritis and homozygotes are normal in viability and fertility. 121 mice may be useful in the study of B cell tolerance to a natural self-antigen.

Development

The L¹²¹ targeting construct contains a loxP-flanked neomycin cassette followed by V_LJ_L sequence from the anti- GPI mAb 6.121 inserted into the J_L region of Igk-J locus on chromosome 6. mAb 6.121 is derived from K/BxN (Tg(TcraR28,TcrbR28)KRNDimxNODF1) mice. The construct was electroporated into 129S4/SvJae-Tg(Prm-cre)70Og-derived embryonic stem (ES) cells. Tg(Prm-cre)70Og expresses Cre recombinase from the protamine promoter allowing cre-mediated excision of the neo cassette from the male germline. Correctly targeted ES cells were injected into blastocysts. The resulting chimeric males were bred to a C57BL/6 females.

The H¹²¹ targeting construct contains a loxP-flanked neomycin cassette followed by V_HD_HJ_H sequence from the anti- GPI mAb 6.121 inserted into the J_H region of Igh-J locus on chromosome 12. mAb 6.12 is derived from K/BxN (Tg(TcraR28,TcrbR28)KRNDimxNODF1) mice. The construct was electroporated into 129S4/SvJae-Tg(Prm-cre)70Og-derived embryonic stem (ES) cells. Tg(Prm-cre)70Og expresses Cre recombinase from the protamine promoter allowing cre-mediated excision of the neo cassette from the male germline during spermatogenesis. Correctly targeted ES cells were injected into blastocysts. The resulting chimeric males were bred to a C57BL/6 females.

H¹²¹ and L¹²¹ mice were bred together and offspring were backcrossed to C57BL/6 for more than 10 generations by the donating laboratory (see SNP note below). Congenic mice were crossed to B6.NOD-H2^g7.

In 2020, 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 males sent to The Jackson Laboratory Repository. One of the 43 markers throughout the genome was segregating with NOD on Chromosome 17, likely a passenger for the NOD-derived H2^g7 haplotype. Also, a marker on Chromosome 13 was also segregating, perhaps with NOD or SJL/J derived from the K/BxN genetic background.

Allele

Symbol: H2^g7
Name: g7 variant
MGI accession ID: MGI:3579321
Generation method: Not Applicable
Synonyms: H-2^g7; H-2g7
Marker symbol: H2
Marker name: histocompatibility-2, MHC
Marker synonyms: H-2; MHC-II
Chromosome: 17
Strain of origin: Not Applicable
General note: The g7 variant has been observed in the following strains: DBR7, NON.NOD-H2^g7

Allele

Symbol: Igk-J^tm1Dim
Name: targeted mutation 1, Diane Mathis
MGI accession ID: MGI:3626300
Generation method: Targeted
Attributes: Inserted expressed sequence
Synonyms: L¹²¹
Marker symbol: Igk-J
Marker name: immunoglobulin kappa chain, joining region
Chromosome: 6
Strain of origin: 129S4/SvJae-Tg(Prm-cre)70Og
Molecular note: A targeting vector containing the mAb 6.121 VkJk sequence and a loxP-flanked neomycin cassette was inserted into the locus to replace the Jk region. Cre mediated recombination subsequently removed the neomycin cassette upon transmission from male chimeric mice.
General note: Targeting took place in ES cells that contain the Tg(Prm-cre)70Og transgene, which expresses Cre recombinase in male germ cells.

Allele

Symbol: Igh-J^tm1Dim
Name: targeted mutation 1, Diane Mathis
MGI accession ID: MGI:3626301
Generation method: Targeted
Attributes: Inserted expressed sequence
Synonyms: H¹²¹
Marker symbol: Igh-J
Marker name: immunoglobulin heavy chain, joining region
Marker synonyms: Jh
Chromosome: 12
Strain of origin: 129S4/SvJae-Tg(Prm-cre)70Og
Molecular note: A targeting vector containing the mAb 6.121 VHDHJH sequence and a loxP-flanked neomycin resistance cassette was inserted into the locus to replace the JH region. Cre mediated recombination subsequently removed the neomycin cassette upon transmission from male chimeric mice.
General note: Targeting took place in ES cells that contain the Tg(Prm-cre)70Og transgene, which expresses Cre recombinase in male germ cells.