T cells from the lymph nodes of T-bet- mice lack T-box transcription factor TBX21, and may be useful in studies of acute and chronic asthma and chronic intestinal inflammation.
Dr. Laurie H. Glimcher, Dana Farber Cancer Institute
Mice that are homozygous for the targeted mutation are viable, fertile and normal in size. No gene product (mRNA or protein) is detected in isolated lymph node T cells by Northern or Western blot analysis. The IFN-γ cytokine induced by CD4 T or NK cells from homozygotes is markedly reduced. CD4 T cells do not produce the TH1-type cytokine interferon gamma but secrete elevated levels of TH2-type cytokines in response to in vitro T cell receptor (TCR) cross-linking and in vivo protein antigen immunization. Additionally, mice homozygous for the targeted mutation on this genetic background are susceptible to Leishmania major infections. Without induced sensitization or challenge, female homozygotes display hyper-responsiveness (AHR) with resulting airway remodeling similar to characteristics of asthma. Histological analysis of lung tissue from female homozygous mice, aged 4 to 6 weeks, reveals eosinophil and lymphocyte infiltration of peribronchial and perivenular tissue, thickening of the subepithelial collagen layer, and increased numbers of myofibroblast cells in bronchial tissue. Bronchial alveolar lavage fluid contains elevated levels of TGFB1 (TGF-beta 1), TNF (TNF-alpha), IL4 and IL13. Mice heterozygous for the targeted mutation display an intermediate phenotype.
A targeting vector was designed to replace exon 1 of the T-box 21 (Tbx21) gene with a neomycin resistance (neo) cassette. The construct was electroporated into 129S6/SvEvTac-derived TC-1 embryonic stem (ES) cells. Correctly targeted ES cells were injected into blastocysts and the resulting chimeric males were bred to C57BL/6 females. These mice were backcrossed to C57BL/6 mice for at least 8 generations. Upon arrival at The Jackson Laboratory, mice were bred to C57BL/6J (Stock No. 000664) for at least one generation to establish the colony.
|Allele Name||targeted mutation 1, Laurie H Glimcher|
|Allele Type||Targeted (Null/Knockout)|
|Allele Synonym(s)||T-bet-; Tbx21-|
|Gene Symbol and Name||Tbx21, T-box 21|
|Strain of Origin||129S6/SvEvTac|
|Molecular Note||A neomycin selection cassette was used to replace a 2 kb region containing exon 1 and its flanking sequence. An absence of mRNA and protein were observed in T cells isolated from the lymph nodes of homozygous mutant mice by Northern blot and Western blot analysis, respectively.|
|Mutations Made By|| |
Dr. Laurie Glimcher, Dana Farber Cancer Institute
The resulting chimeric animals were crossed to C57BL/6 mice, and then backcrossed to C57BL/6 for 8 generations. The strain is maintained as a homozygote. Expected coat color is black non-agouti.
When using the T-bet- mouse strain in a publication, please cite the originating article(s) and include JAX stock #004648 in your Materials and Methods section.