B6(FVB)-Tlr7^tm1.1Gbrt/J

Stock number: 031827
Product name: TLR7KI-tdTom
Research areas: Immunology, Inflammation and Autoimmunity Research, Research Tools

Description

TLR7KI knock-in mice have a FLAG tag and an IRES-tdTomato sequence placed at the 3' end of the toll-like receptor 7 (Tlr7) gene. These mice may be useful as a reporter when studying pathogen recognition and activation of innate immunity.

The Jackson Laboratory has two Tlr7 knock-in alleles available: the TLR7KI-tdTom knock-in allele with an IRES-tdTomato at the 3' end (Tlr7^tm1.1Gbrt; Stock No. 031827) and the Tlr7 knock-in/knock-out allele with lacZ replacing exon 3 (Tlr7^tm1Flv; Stock No. 008380).

Detailed description

TLR7KI knock-in mice have a FLAG tag and an IRES-tdTomato sequence placed at the 3' end of the X-linked toll-like receptor 7 (Tlr7) gene. TLR7 is a cell-surface receptor which plays a fundamental role in pathogen recognition and activation of innate immunity. This gene has been implicated in the pathogenesis of several autoimmune diseases including inflammatory bowel disease and Crohn's Disease, as well as some intestinal cancers. In these mice, tdTomato is expressed in splenic CD11c⁺ dendritic cells (DCs). Extremely low tdTomato levels are evident in intestinal epithelial cells (IECs) throughout the small intestine and the proximal colon, with similar expression seen in neonates as seen in adults. tdTomato can be detected by using FACS analysis or immunohistochemistry. Homozygous females and hemizygous males are viable and fertile.

Of note, similar TLR reporter mice are available:
TLR2KI knock-in mice (Stock No. 031822) contain an HA tag and an IRES-EGFP sequence.
TLR4KI knock-in mice (Stock No. 031824) contain an HA tag and an IRES-EYFP sequence.
TLR5KI knock-in mice (Stock No. 031825) contain an HA tag and an IRES-tdTomato sequence.
TLR9KI knock-in mice (Stock No. 031829) contain an HA tag and an IRES-EGFP sequence.

Development

The TLR7KI targeting vector was designed to insert a FLAG tag, followed by an internal ribosome entry site (IRES) fused to an enhanced red fluorescent protein (tdTomato) sequence, at the 3' end of the X-linked toll-like receptor 7 (Tlr7) gene. The vector also contained a loxP-flanked neomycin selection (neo) cassette. The construct was electroporated into C57BL/6N-derived embryonic stem (ES) cells. Correctly targeted ES cells were injected into ICR/CD1 blastocysts and the resulting chimeric males were bred to B6.FVB-Tg(EIIa-cre)C5379Lmgd/J mice (Stock No. 003724) to remove the neo cassette, and mice were subsequently bred to C57BL/6N mice to remove the cre-expressing transgene. TLR7KI mice were bred to C57BL/6N mice for at least two generations. Upon arrival, sperm was cryopreserved. To establish our live colony, an aliquot of frozen sperm was used to fertilize C57BL/6NJ oocytes (Stock No. 005304).

Allele

Symbol: Tlr7^tm1.1Gbrt
Name: targeted mutation 1.1, Gregory M Barton
MGI accession ID: MGI:6154642
Generation method: Targeted
Attributes: Reporter; Epitope tag
Synonyms: Tlr7^{FLAG:tdTomato}; TLR7^TOM
Marker symbol: Tlr7
Marker name: toll-like receptor 7
Marker synonyms: IMD74; RGD1563357; SLEB17; TLR7-like
Chromosome: X
Strain of origin: C57BL/6N
Expressed genes: FLAG, FLAG octapeptide,; RFP,Red Fluorescent Protein,coral
Site of expression: tdTomato is expressed in splenic CD11c⁺ dendritic cells. Extremely low tdTomato levels are evident in intestinal epithelial cells throughout the small intestine and the proximal colon, with similar expression seen in neonates as seen in adults.
Molecular note: A FLAG tag was fused to the 3' end of the gene followed by an IRES-tdTomato reporter via homologous recombination. The vector also contained a loxP-flanked neomycin selection (neo) cassette, which was removed following Cre-mediated recombination.