B6(Cg)-Tlr3^tm1.1Lwtn/J

Stock number: 036399
Product name: TLR3 flox
Research areas: Cell Biology Research, Immunology, Inflammation and Autoimmunity Research, Research Tools

Description

TLR3 flox mice have loxP sites flanking exon 6 and part of exon 7 of the Tlr3 gene. These mice are useful for studying the toll-like receptor pathway of innate immune response.

Detailed description

TLR3 flox mice have loxP sites flanking exon 6 and part of exon 7 of the toll-like receptor 3 (Tlr3) gene. TLR3 is highly expressed in placenta and pancreas, and the CD8⁺ dendritic subpopulation of leukocytes. It recognizes double-stranded (ds)RNA associated with viral infection, and induces the activation of NF-kappaB and the production of type I interferons. Mice that are homozygous for this floxed allele are viable and fertile. When bred to mice that express tissue-specific cre recombinase, resulting offspring will have exon 6 and part of exon 7 deleted in the cre-expressing tissues.

When bred to a CMV-Cre mice (Stock No. 006054) with global cre recombinase expression, resulting TLR3 delta/delta mice lack exon 6 and part of exon 7. These mice exhibit more than a 90% reduction of TLR3 protein in splenocytes. CD80, CD86, and MHC-II expression in splenocytes are all dramatically reduced in the delta/delta cells in response to poly(I:C), with no differences seen in these cells in response to LPS or to R848 (data not published).

Development

The L1L2_Bact_P cassette was inserted at a position on Chromosome 8 downstream of exon 5 of the toll-like receptor 3 (Tlr3) gene. The cassette is composed of an FRT site followed by a β-galactosidase (lacZ) gene, and a polyadenylation site (SV40 polyA). This was followed by a loxP site, a neomycin resistance gene, a SV40 polyA, a second FRT site and a second loxP site. A third loxP site is inserted in exon 7. The targeting vector PG00208_Z_6_B10 was electroporated into C57BL/6-derived embryonic stem (ES) cells by Taishi Kimura and Claudia Flynn in the laboratory of J. Lindsay Whitton (Scripps Research), and correctly targeted ES cells were injected into blastocysts. The resulting chimeric mice were bred to Flp recombinase expressing albino B6 mice to remove the neo and lacZ sequences. Mice were crossed to remove the Flp-expressing transgene, and the resulting black TLR3 flox mice were backcrossed to C57BL/6J mice for at least 5 generations by the donating laboratory (see SNP note below). Upon arrival at The Jackson Laboratory, sperm was cryopreserved. To establish our live colony, an aliquot of frozen sperm was used to fertilize C57BL/6J oocytes (Stock No. 000664) to make a live colony.

In 2021, 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. Three of the 5 markers that determine C57BL/6J from C57BL/6N were found to be segregating, including the rd8 recessive mutation associated with retinal degeneration on Chromosome 1 within the Crb1 locus. These data suggest the mice sent to The Jackson Laboratory Repository were on a mixed C57BL/6N;C57BL/6J genetic background.

Allele

Symbol: Tlr3^tm1.1Lwtn
Name: targeted mutation 1.1, J Lindsay Whitton
MGI accession ID: MGI:6704903
Generation method: Targeted
Attributes: Conditional ready (e.g. floxed)
Marker symbol: Tlr3
Marker name: toll-like receptor 3
Marker synonyms: CD283; IIAE2; IMD83
Chromosome: 8
Strain of origin: C57BL/6
Molecular note: Targeting vector PRPGS00208_A_B10 from the KOMP Repository was used to create the allele. The construct includes an FRT site followed by a beta-galactosidase (lacZ) gene, and a polyadenylation site (SV40 polyA). This was followed by a loxP site, a neomycin resistance gene, a SV40 polyA, a second FRT site and a second loxP site inserted downstream of exon 5. A third loxP site is inserted in exon 7. Flp-mediated recombination removed the FRT-flanked neo cassette/lacZ sequences.