B6(Cg)-Clec9a^tm1.1Crs/J

Stock number: 017696
Product name: Clec9a^gfp
Strain synonyms: DNGR-1–deficient
Research areas: Cell Biology Research, Immunology, Inflammation and Autoimmunity Research, Research Tools

Description

A membrane-bound form of enhanced green fluorescent protein (EGFP) replaces the coding region of Clec9a and abolishes gene expression. These mice may be useful for studying adaptive immune responses to antigens in apoptotic and necrotic cells.

Detailed description

The coding region of the C-type lectin domain family 9, member a (Clec9a) gene is replaced by a membrane-bound farnesylated form of enhanced green fluorescent protein (EGFP), abolishing gene expression. Clec9a encodes for DNGR-1, an endocytic receptor of the C-type lectin superfamily that is selectively expressed at high levels by CD8α+ dendritic cells (DC) and at lower levels by plasmacytoid DC. DNGR-1 recognizes an intracellular ligand that is exposed in dead cells and facilitates cross-presentation of dead-cell-associated antigens through a mechanism that involves interaction of its intracellular tail with the tyrosine kinase, SYK. Homozygous mice are viable and fertile. In these mice, EGFP expression is detected on CD8α+ DC but not on plasmacytoid DC. DNGR-1 KO mice exhibit a selective deficiency in cross-priming of CD8+ T cells against dead-cell-associated antigens. The phagocytosis of dead cells by DCs is unaffected by loss of DNGR-1 and DC number and phenotype are also unchanged compared to control. These mice may be useful for studying adaptive immune responses to antigens in apoptotic and necrotic cells.

Of note, other CLEC9A expressing lines are available:
Clec9a^cre knock-in/knock-out mice (Stock No. 025523) have a codon improved cre recombinase sequence replacing the endogenous Clec9a sequence.
Clec9a^Cre/ERT2 knock-in (Stock No. 037804) have cre/ERT2 inserted into the C-terminus of the endogenous Clec9a sequence and retain endogenous gene expression.
Clec9a^tdTomato knock-in/knock-out mice (Stock No. 037805) have a tdTomato sequence inserted into the endogenous Clec9a start site, abolishing expression.

Development

A targeting vector was designed to replace the C-type lectin domain family 9, member a (Clec9a) coding region with a farnesylated form of enhanced green fluorescent protein (EGFP), a polyadenylation signal, and a loxP-flanked neomycin (neo) resistance cassette. This construct was electroporated into (129S6/SvEvTac x C57BL/6) F1-derived embryonic stem (ES) cells. Correctly targeted ES cells were injected into recipient C57BL/6 blastocysts and chimeric males were bred with C57BL/6J females. Mutant mice were bred with Tg(Pgk-cre)1Lni mice (on a C57BL/6J congenic background) to remove the neo selection cassette. These Clec9a^gfp/gfp mice were subsequently bred to C57BL/6J mice for at least 7 generations. Upon arrival at The Jackson Laboratory Repository, mice were bred with C57BL/6J inbred mice (Stock No. 000664) for at least one generation.

Allele

Symbol: Clec9a^tm1.1Crs
Name: targeted mutation 1.1, Caetano Reis e Sousa
MGI accession ID: MGI:5298406
Generation method: Targeted
Attributes: Reporter; Null/Knockout
Marker symbol: Clec9a
Marker name: C-type lectin domain family 9, member a
Chromosome: 6
Strain of origin: (129S6/SvEvTac x C57BL/6J)F1
Expressed genes: GFP,Green Fluorescent Protein,
Site of expression: EGFP expression is detected on CD8α⁺ dendritic cells but not on plasmacytoid DC.
Molecular note: A targeting vector was designed to replace the C-type lectin domain family 9, member a (Clec9a) coding region with a farnesylated form of enhanced green fluorescent protein (EGFP), a polyadenylation signal, and a loxP-flanked neomycin (neo) resistance cassette. Cre-mediated recombination removed the neo cassette.
General note: The expression of NK1.1 (Klrb1c) is linked to Clec9a deficiency in homozygous mice, indicating that the homologous recombination step targeted the chromosome of C57BL/6J origin.