B6J.B6N(Cg)-Clec9a^{tm2.1(icre)Crs}/J

Stock number: 025523
Product name: Clec9a^cre
Research areas: Cell Biology Research, Immunology, Inflammation and Autoimmunity Research, Research Tools

Description

These mice express a codon improved Cre-recombinase in conventional dendritic cell precursors and may be useful for dendritic cell lineage fate mapping.

Detailed description

The coding region of the C-type lectin domain family 9, member a (Clec9a) gene is replaced by a codon improved version of Cre-recombinase (iCre), 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. When Clec9a^cre mice are bred with mice containing loxP-flanked sequence, iCre-mediated recombination will result in deletion of the floxed sequences in conventional DC precursors of the offspring.

Of note, other CLEC9A expressing lines are available:
Clec9a^gfp knock-in/knock-out mice (Stock No. 017696) have an EGFP 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 codon improved version of Cre-recombinase (iCre), a polyadenylation signal, and a loxP-flanked neomycin (neo) resistance cassette. This construct was electroporated into C57BL/6NTac-derived PRX-B6N embryonic stem (ES) cells. Correctly targeted ES cells were injected into recipient blastocysts and chimeric males were bred with C57BL/6J females. Mutant mice were bred with B6.C-Tg(Pgk-cre)1Lni mice to remove the neo selection cassette. These Clec9a^cre mice were subsequently bred to C57BL/6J mice for at least 8 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^{tm2.1(icre)Crs}
Name: targeted mutation 2.1, Caetano Reis e Sousa
MGI accession ID: MGI:5502446
Generation method: Targeted
Attributes: Recombinase-expressing
Marker symbol: Clec9a
Marker name: C-type lectin domain family 9, member a
Chromosome: 6
Strain of origin: C57BL/6NTac
Expressed genes: cre,cre recombinase,bacteriophage P1
Site of expression: Cre-recombinase is expressed in conventional dendritic cell precursors.
Molecular note: An existing targeting vector was modified by inserting a codon-improved cre sequence in place of the EGFP sequence in the pFloxRI-C9a-EGFP construct. This construct was electroporated into PRX-B6N (Primogenix) for homologous recombination. Animals carrying the cre allele were crossed to PGK-cre mice to delete the floxed neomycin selection cassette.