This Cr2 (CD21) knockout strain exhibits defective memory B cell differentiation and reduced levels of IgG and IgM. These mice may be suitable for use in studies of humoral immune response, the activation and proliferation of B cells and adult neurogenesis.
Xiaodi Wu, Washington Univ. Sch. Med
Hector Molina, Washington University School of Medicine
Genetic Background | Generation |
---|---|
N8+pN1F8
|
Allele Type | Gene Symbol | Gene Name |
---|---|---|
Targeted (Null/Knockout) | Cr2 | complement receptor 2 |
Complement receptor 2 is involved with immune homeostasis, specifically lymphocyte activation in primary immune responses to T dependent antigens and in the generation of memory B cells. In the mouse, complement receptors type 1 and type 2 are encoded by a single Cr2 gene by alternate splicing of a single RNA product.
Flow cytometry of spleen cells from homozygotes reveals the deficiency of complement receptors type 1 and type 2. Homozygotes exhibit reduced levels of IgG after immunization with a T-cell dependent antigen. In the hippocampus of homozygous mice, there is a 2 to 3 fold increase in immature neurons and an approximately 40% increase in mature neurons. Bacterial clearance is delayed and survival from pneumococcal infection is significantly reduced (only 20% survive) in homozygotes. Onset of scrapie (spongiform encephalopathy) is delayed after intraperitoneal inoculation of prions. In experimentally induced intestinal ischemia-reperfusion injury, there is less resulting tissue injury in mutant mice when compared to wildtype controls.
Mice that are homozygous for this targeted knock-out of the Cr2 gene are viable and fertile. No gene product (mRNA) is detected by Northern blot analysis.
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. This is the case for the strain above. It should be noted that the phenotype could vary from that originally described. We will modify the strain description if necessary as published results become available.
A targeting vector designed by Dr. Hector Molina (Washington University School of Medicine, St. Louis,
MO) containing a PGK-NEO cassette, pGKneobpA, was used to disrupt part of exon 1 and exon 2, encoding the short consensus repeat (SCR) 14. The construct was electroporated into 129S7/SvEvBrd-Hprt+-derived AB1 embryonic stem (ES) cells. Correctly targeted ES cells were injected into blastocysts. The resulting chimeric animals were tested for germline transmission.
The mice were crossed to C57BL/6 for an unknown number of generations before being backcrossed to NOD for 13 generations. Upon arrival at The Jackson Laboratory in 2007, the mice at generation N13F5 on NOD were crossed to C57BL/6J (Stock No. 000664) for 5 or 6 generations, using a marker assisted protocol. Sperm was then cryopreserved.
Allele Name | targeted mutation 1, Hector Molina |
---|---|
Allele Type | Targeted (Null/Knockout) |
Allele Synonym(s) | CD21-KO; Cr; CR1/2-; CR1/CR2-; Cr2- |
Gene Symbol and Name | Cr2, complement receptor 2 |
Gene Synonym(s) | |
Strain of Origin | 129S7/SvEvBrd-Hprt+ |
Chromosome | 1 |
Molecular Note | A PGK-neomycin resistance cassette replaced part of the first and all of the second exon encoding short consensus repeat (SCR) 14. Flow cytometry of spleen cells using three different rat antimouse CR2 monoclonal antibodies showed that homozygous mutant mice were deficient in the expression of the receptors. |
When maintaining a live colony, these mice can be bred as homozygotes.
When using the CD21-KO mouse strain in a publication, please cite the originating article(s) and include JAX stock #008225 in your Materials and Methods section.
Service/Product | Description | Price |
---|---|---|
Heterozygous or wildtype for Cr2<tm1Hmo> |
Frozen Mouse Embryo | B6.129S7(NOD)-Cr2<tm1Hmo>/J Frozen Embryo | $2595.00 |
Frozen Mouse Embryo | B6.129S7(NOD)-Cr2<tm1Hmo>/J Frozen Embryo | $2595.00 |
Frozen Mouse Embryo | B6.129S7(NOD)-Cr2<tm1Hmo>/J Frozen Embryo | $3373.50 |
Frozen Mouse Embryo | B6.129S7(NOD)-Cr2<tm1Hmo>/J Frozen Embryo | $3373.50 |
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The Jackson Laboratory has rigorous genetic quality control and mutant gene genotyping programs to ensure the genetic background of JAX® Mice strains as well as the genotypes of strains with identified molecular mutations. JAX® Mice strains are only made available to researchers after meeting our standards. However, the phenotype of each strain may not be fully characterized and/or captured in the strain data sheets. Therefore, we cannot guarantee a strain's phenotype will meet all expectations. To ensure that JAX® Mice will meet the needs of individual research projects or when requesting a strain that is new to your research, we suggest ordering and performing tests on a small number of mice to determine suitability for your particular project. We do not guarantee breeding performance and therefore suggest that investigators order more than one breeding pair to avoid delays in their research.
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