STOCK Ltb/Tnf^tm1.1Dvk/J

Stock number: 005112
Product name: (LTΒ/TNF)^Δ/Δ

Description

These Ltb/Tnf double knock-out mice exhibit impaired development of peripheral lymphoid tissue and disrupted spleen structure.

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) is detected by RNase protection assay of concanavalin-A activated splenocytes. Lta gene transcription is not effected. Peripheral lymphoid tissue development is impaired. Only mesenteric lymph nodes and few sacral lymph nodes are found in homozygotes, and these have abnormal morphology. Spleen structure is disrupted and no germinal centers form following antigenic challenge. This double mutant strain exhibits a phenotype more severe than the phenotypes exhibited by either of the single targeted mutation strains of the genes. This mutant mouse strain may be useful in studies of peripheral lymphoid organ development, antibody response to T cell dependent antigens.

Development

A targeting vector containing a neomycin resistance gene driven by the mouse phosphoglycerate kinase promoter flanked by a single loxP site, herpes simplex virus thymidine kinase gene and three additional loxP sites inserted between the Ltb and Tnf genes, between exons 2 and 3 of the Tnf gene and adjacent to exon 2 of the Lta gene, was utilized in the construction of this mutant. The construct was electroporated into 129Ps/OlaHsd derived E14.1 embryonic stem (ES) cells. Correctly targeted ES cells were injected into C57BL/6 blastocysts. The resulting chimeric male mice were crossed to C57BL/6 mice, and then crossed to cre deleter strain, BALB/c-Tg(CMV-cre)1Cgn/J (STOCK#3464) to remove the floxed 5.3kb sequence containing the neo selection cassette, exon 3 of Ltb and exons 3-4 of Tnf. The mice were then backcrossed onto the C57BL/6 for 7 generations, during which the cre transgene was bred out of the strain.

Allele

Symbol: Ltb/Tnf^tm1.1Dvk
Name: targeted mutation 1.1, Dmitry V Kuprash
MGI accession ID: MGI:2446565
Generation method: Targeted
Attributes: Null/Knockout
Marker symbol: Tnf
Marker name: tumor necrosis factor
Chromosome: 17
Strain of origin: 129P2/OlaHsd
Molecular note: The floxed 5.3 kb region, containing exon 3 of the Ltb locus and exons 3 and 4 of the Tnf locus, was excised via in vivo cre mediated recombination between the loxP site within the Ltb locus and the loxP site within the Tnf locus. The deleted regions encoded the majority of the extracellular region of Ltb and the entire secreted portion of Tnf. An RNAse protection assay using homozygous mutant concavalin A stimulated splenocytes detected a truncated Ltb transcript and demonstrated normal transcription of the closely linked Lta locus.

Allele

Symbol: Ltb/Tnf^tm1.1Dvk
Name: targeted mutation 1.1, Dmitry V Kuprash
MGI accession ID: MGI:2446564
Generation method: Targeted
Attributes: Null/Knockout
Marker symbol: Ltb
Marker name: lymphotoxin B
Chromosome: 17
Strain of origin: 129P2/OlaHsd
Molecular note: The floxed 5.3 kb region, containing exon 3 of the Ltb locus and exons 3 and 4 of the Tnf locus, was excised via in vivo cre mediated recombination between the loxP site within the Ltb locus and the loxP site within the Tnf locus. The deleted regions encoded the majority of the extracellular region of Ltb and the entire secreted portion of Tnf. An RNAse protection assay using homozygous mutant concavalin A stimulated splenocytes detected a truncated Ltb transcript and demonstrated normal transcription of the closely linked Lta locus.