Dectin-1 knockout (clec7a-/-) mice are susceptible to fungal infection of C. albicans SC5314; resulting in substantially increased fungal burden and dysregulated cytokine responses. These mice may be useful in studying the innate/adaptive immune response and cytokine/chemokine production following fungal pathogen infection, as well as the collaborative responses mediated between different pattern recognition receptors (PRRs) to identify pathogen-associated molecular patterns (PAMPs) and achieve specific host responses to infectious agents (including the Dectin-1/Syk/CARD9/Th17 and TLR2/MyD88/NF-kB signaling pathways).
Gordon D Brown, University of Aberdeen
The Dectin-1 knockout (clec7a-) allele has the sequences corresponding to the cytoplasmic tail, transmembrane and stalk regions of the Dectin-1 locus (Clec7a) deleted. Using flow cytometry, no expression of the Dectin-1 receptor is observed on peripheral leukocytes isolated from homozygous mice (leukocytes from heterozygous mice have an intermediate expression level).
Dectin-1-mediated control of systemic Candida albicans infection in vivo is i) fungal strain-specific and ii) independent of the murine genetic background.
Dectin-1 knockout mice on a C57BL/6 genetic background (B6.clec7a-/-) have greatly increased susceptibility to fungal infection of C. albicans SC5314, resulting in substantially increased fungal burden and dysregulated cytokine responses. However, Dectin-1-deficiency has no effect on susceptibility to C. albicans ATCC18804. Similar results are reported for Dectin-1 knockout mice on a 129Sv genetic background (129Sv.clec7a-/-).
When similarly challenged in vitro, Dectin-1-deficient leukocytes show significantly impaired antifungal inflammatory responses. Unlike wildtype bone marrow-derived dendritic cells (BMDC), Dectin-1-deficient BMDC do not exhibit the enhanced TNF, IL-10, IL-6, and IL-23 production following co-stimulation of Dectin-1/TLR2. Of note, the C. albicans strain-specificity for Dectin-1 is not recapitulated in vitro.
Homozygous mice are viable and fertile, with no gross reported abnormalities and normal peripheral leukocyte counts.
These Dectin-1 mutant mice may be useful in studying the innate/adaptive immune response and cytokine/chemokine production following fungal pathogen infection, as well as the collaborative responses mediated between different pattern recognition receptors (PRRs) to identify pathogen-associated molecular patterns (PAMPs) and achieve specific host responses to infectious agents (including the Dectin-1/Syk/CARD9/Th17 and TLR2/MyD88/NF-kB signaling pathways).
In an attempt to offer alleles on well-characterized or multiple genetic backgrounds, alleles are frequently moved to a genetic background different from that on which an allele was first characterized. It should be noted that the phenotype of Dectin-1 knockout mice on a C57BL/6 genetic background is published in Marakalala et al. 2013 PLoS Pathog 9:e1003315, and could vary from that originally described on a 129S6/Sv genetic background. We may modify the strain description if necessary as published results become available.
A targeting vector was designed to replace the first three exons of the Clec7a Dectin-1 locus (Clec7a) with a reverse-oriented neomycin resistance cassette. The construct was electroporated into 129S6/Sv-derived embryonic stem (ES) cells. Correctly targeted ES cells were injected into recipient blastocysts and chimeric males were bred with 129S6/Sv females to establish the colony. Mice on the 129S6/Sv genetic background were then backcrossed onto the C57BL/6J genetic background for 11 generations. In 2015, mice were sent to The Jackson Laboratory Repository. Upon arrival, sperm was cryopreserved. To generate the living colony, an aliquot of the frozen sperm was used to fertilize oocytes from C57BL/6J female mice (Stock No. 000664). The Dectin-1 mutant mice were then bred together to maintain the colony.
|Allele Name||targeted mutation 1, Gordon D Brown|
|Allele Type||Targeted (Null/Knockout)|
|Allele Synonym(s)||Clec7a-; dectin-1-|
|Gene Symbol and Name||Clec7a, C-type lectin domain family 7, member a|
|Strain of Origin||129S6/SvEvTac|
|Molecular Note||Exons 1-3 were replaced with a neomycin resistance gene.|
|Mutations Made By|| |
Gordon Brown, University of Aberdeen
When maintaining a live colony, homozygous mice may be bred together. Homozygous mice have greatly increased susceptibility to fungal infection of C. albicans strain SC5314.
When using the Dectin-1 KO (clec7a KO) mouse strain in a publication, please cite the originating article(s) and include JAX stock #012337 in your Materials and Methods section.