B6.129S4(C)-C5ar1^tm1Cge/BaoluJ

Stock number: 033903
Product name: C5aRKO
Research areas: Immunology, Inflammation and Autoimmunity Research, Research Tools

Description

Deficiency of complement component 5a receptor 1 in these C5ar1^tm1Cge knock-out mice affects a wide range of physiological responses, and has been implicated in autoimmune and inflammatory disorders.

Detailed description

Mice homozygous for the targeted mutation are viable, fertile, normal in size, and do not display any gross physical or behavioral abnormalities when maintained under barrier conditions. No mRNA is detected by Northern blot analysis of bone marrow cells isolated from homozygotes, and neutrophils fail to respond to recombinant C5a in vitro. The immune response of homozygous mice following inoculation or challenge has been characterized on a C57BL/6 background in a number of studies. Following intratracheal inoculation, mutant mice have impaired bacterial clearance in the lungs, associated with extensive secondary infection, despite increased neutrophil accumulation. Conversely, homozygous mutants are protected against immune-complex-associated injury in the lung, peritoneum, skin, and kidney but not against experimental autoimmune encephalomyelitis. Induced acute pancreatitis and pancreatitis-associated lung injury is more severe in homozygotes compared to wildtype. On a BALB/c background, homozygous mutant mice are more resistant to dermal infection, and lymph node cells have greatly increased antigen recall, as measured by interferon gamma secretion, compared to wild type. Homozygotes fail to develop airway hyper-reactivity in hapten asthma models (background not-identified). This mutant can be used to study many lung-associated diseases, immune complex associated injury, and complement-mediated innate immunity.

Of note, this allele is also available on a congenic BALB/cJ background as Stock No. 006845.

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 these C57BL/6J-congenic mice could vary from that originally described on a BALB/cJ congenic background. We may modify the strain description if necessary as published results become available.

Development

A targeting vector containing a mouse phosphoglycerate kinase promoter-driven neomycin resistance gene was used to replace the entire coding region of the endogenous gene. The construct was electroporated into the 129S4/SvJae-derived J1 embryonic stem (ES) cells, and correctly targeted ES cells were injected into C57BL/6 blastocysts. The resulting chimeric males were crossed to C57BL/6 females. Heterozygotes were mated to C57BL/6 mice for 2 generations and then backcrossed 10 generations to BALB/c before being made homozygous. These mice are available as Stock No. 006845. The donating lab reports that some of these mice were further backcrossed to C57BL/6J mice (Stock No. 000664) for 15 generations by Dr. Craig Gerard (Boston Children's Hospital) before being sent back to The Jackson Laboratory (see SNP note below). Upon arrival, sperm was cryopreserved. To establish our live colony, an aliquot of frozen sperm was used to fertilize C57BL/6J oocytes.

In 2019, 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. One of the 43 markers throughout the genome was segregating with 129, likely passenger segment from C5ar1 mutation. Also, 4 of 5 markers that determine C57BL/6J from C57BL/6N were segregating, three of those markers (one each on chromosomes 8, 15 and 19) score the same for C57BL/6N or BALB/c, while the chromosome 1 marker within the Crb1 locus was homozygous for C57BL/6N - indicating presence of the rd8 recessive mutation associated with retinal degeneration. Taken together, these data suggest that the mice sent to The Jackson Laboratory Repository were on a mixed C57BL/6J;C57BL/6N genetic background. The live colony was additionally backcrossed to C57BL/6J for a least one or more generations, and may be segregating for rd8.

Allele

Symbol: C5ar1^tm1Cge
Name: targeted mutation 1, Craig Gerard
MGI accession ID: MGI:1934246
Generation method: Targeted
Attributes: Null/Knockout
Synonyms: C5aR-; C5aRKO
Marker symbol: C5ar1
Marker name: complement component 5a receptor 1
Marker synonyms: C5A; C5AR; C5a-R; C5r1; Cd88; D7Msu1
Chromosome: 7
Strain of origin: 129S4/SvJae
Molecular note: A PGK-neomycin resistance cassette replaced the entire coding region of the gene. Northern analysis of bone marrow cells did not detect expression in homozygous mutant mice.