These floxed mutant mice possess loxP sites flanking exon 3 of the Tlr4 gene. This strain may be useful for generating conditional mutations in applications related to the study of innate immune responses.
Christopher Karp, Bill & Melinda Gates Foundation
Donald N. Cook, NIH/NIEHS
The Tlr4, toll-like receptor 4, gene encodes a protein that has a critical role in pathogen recognition and activation of the innate immune system.
These mice possess loxP sites on either side of exon 3 of the targeted Tlr4 gene. Mice that are homozygous for this allele are viable and fertile. When these mutant mice are bred to mice that express Cre recombinase, resulting offspring will have exon 3 deleted in the cre-expressing tissues.
A targeting vector containing a FRT site flanked NEO selection cassette was utilized in the construction of this mutant. This selection cassette and a loxP site was inserted downstream of exon 3 of the targeted gene, and another loxP site was inserted upstream of exon 3. This construct was electroporated into C57BL/6J derived CMTI-2 embryonic stem (ES) cells. Correctly targeted ES cells were injected into blastocysts. The resulting chimeric animals were crossed to albino C57BL/6 mice (Stock No. 000058). The mice were then bred to transgenic mice (on the B6.Cg genetic background) expressing FLPe recombinase under the control of the human ACTB promoter (Stock No. 005703) to remove the FRT flanked selection cassette. The mice were then bred to C57BL6/J mice by the donating laboratory (see SNP note below). Heterozygotes were then bred to generate homozygotes. Upon arrival at The Jackson Laboratory, the mice were crossed to C57BL/6J (Stock No. 000664) at least once to establish the colony.
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 5 markers that determine C57BL/6J from C57BL/6N was found to be segregating, on Chromosome 15. These data suggest the mice sent to The Jackson Laboratory Repository were on a mixed C57BL/6N;C57BL/6J genetic background.
|Allele Name||targeted mutation 1.1, Christopher Karp|
|Allele Type||Targeted (Conditional ready (e.g. floxed))|
|Gene Symbol and Name||Tlr4, toll-like receptor 4|
|Strain of Origin||C57BL/6J|
|Molecular Note||A targeting vector containing a FRT site flanked neomycin selection cassette and a loxP site was inserted downstream of exon 3 of the targeted gene, and another loxP site was inserted upstream of exon 3. Mutant mice were bred with ACT-FLPe mice (on a C57BL/6 congenic background) to remove the neomycin selection cassette.|
When maintaining a live colony, these mice can be bred as homozygotes.
When using the Tlr4fl mouse strain in a publication, please cite the originating article(s) and include JAX stock #024872 in your Materials and Methods section.