B6.129P2-Ltb/Tnf/Lta^tm1Dvk/J

Stock number: 005108
Product name: TNF/LTΔ3

Description

These Lta/Ltb/Tnf triple knock-out mice have abnormal lymphoid development and spleen microarchitecture, and display defective antibody responses.

Detailed description

Mice that are homozygous for the targeted mutation are viable, fertile, normal in size and do not display any gross physical or behavioral abnormalities. No gene product (mRNA) from any of the three targeted genes is detected by RT-PCR analysis of concanavalin-A activated splenocytes. Leukocyte numbers in the spleen, blood and peritoneal cavity are increased 2 to 3 fold. Homozygous mice have abnormal lymphoid development and do not develop Peyer's patches or lymph nodes. Spleen microarchitecture is abnormal. No germinal center forms in the spleen following antigenic challenge. Mutant mice display defective antibody responses. This strain displays a phenotype more severe than the phenotypes exhibited by any of the single targeted mutation strains of the genes and may be useful in studies of peripheral lymphoid organ development, and antibody response to T cell dependent antigens.

Development

A targeting vector containing neomycin resistance and herpes simplex virus thymidine kinase genes, and four loxP sites, flanking each of the three genes, was used to disrupt 8.4 kb of sequence encoding all of the Tnf gene and the last exons of the Lta and Ltb genes. The construct was electroporated into 129P2/OlaHsd derived E14.1 embryonic stem (ES) cells. Correctly targeted ES cells were transiently transfected with a cre expression plasmid for the purpose of removing the selectable marker cassette. ES cells that had successfully undergone Cre-mediated recombination and no longer retained the cassette were injected into C57BL/6 blastocysts. The donating investigator reported that the resulting chimeric animals were crossed to C57BL/6 mice, and then backcrossed to for 12 generations (see SNP note below).

A 32 SNP (single nucleotide polymorphism) panel analysis, with 27 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. While the 27 markers throughout the genome suggested a C57BL/6 genetic background, 3 of 5 markers that determine C57BL/6J from C57BL/6N were found to be segregating. These data suggest the mice sent to The Jackson Laboratory Repository were on a mixed C57BL/6J ; C57BL/6N genetic background.

Allele

Symbol: Ltb/Tnf/Lta^tm1Dvk
Name: targeted mutation 1, Dmitry V Kuprash
MGI accession ID: MGI:2446567
Generation method: Targeted
Attributes: Null/Knockout
Marker symbol: Tnf
Marker name: tumor necrosis factor
Chromosome: 17
Strain of origin: Not Specified
Molecular note: An 8.4 kb region, containing the entire Tnf gene and the last coding exons of the Lta and Ltb genes, was deleted by cre mediated recombination of surrounding loxP sites inserted within Lta and Ltb via homologous recombination. Partial coding regions of Lta and Ltb were left intact separated by a single loxP site, however RT-PCR analysis of homozygous mutant splenocytes activated by concanavalin A indicated an absence of transcript from each locus.

Allele

Symbol: Ltb/Tnf/Lta^tm1Dvk
Name: targeted mutation 1, Dmitry V Kuprash
MGI accession ID: MGI:2446568
Generation method: Targeted
Attributes: Null/Knockout
Marker symbol: Ltb
Marker name: lymphotoxin B
Chromosome: 17
Strain of origin: Not Specified
Molecular note: In an 8.4 kb region, containing the entire Tnf gene and the last coding exons of the Lta and Ltb genes, was deleted by cre mediated excision of sequence between loxP sites inserted within Lta and Ltb via homologous recombination. Partial coding regions of Lta and Ltb were left intact separated by a single loxP site. RT-PCR analysis of homozygous mutant splenocytes activated by concanavalin A indicated an absence of transcript from all three loci.

Allele

Symbol: Ltb/Tnf/Lta^tm1Dvk
Name: targeted mutation 1, Dmitry V Kuprash
MGI accession ID: MGI:2446566
Generation method: Targeted
Attributes: Null/Knockout
Marker symbol: Lta
Marker name: lymphotoxin A
Chromosome: 17
Strain of origin: Not Specified
Molecular note: An 8.4 kb region, containing the entire Tnf gene and the last coding exons of the Lta and Ltb genes, was deleted by cre mediated recombination of surrounding loxP sites inserted within Lta and Ltb via homologous recombiantion. Partial coding regions of Lta and Ltb were left intact separtated by a single loxP site, however RT-PCR analysis of homozygous mutant splenocytes activated by concanavalin A indicated an absence of transcript from each locus.