Mice that are homozygous for the targeted mutation are viable, fertile, normal in size and do not display any gross physical or behavioral abnormalities. However, the donating investigator reports that reproductive performance is poor for unknown reasons. No gene product (mRNA or protein) is detected by Northern blot analysis of liver and kidney or Western blot analysis of peritoneal macrophages. Mutant mice exhibit an impaired type I cytokine immune response with reduced induced interferon gamma production. Macrophages from mutant mice have a reduced p39 MAPK activation and IL-12 production when challenged with LPS lipopolysaccharide). Dendritic cells also have reduced IL-12 production response. Mutant mouse embryo fibroblasts (MEF) have a reduced cytokine expression response to tumor necrosis factor (TNF). This mutant mouse strain may be useful in studies of inflammatory response.
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 containing neomycin resistance and herpes simplex virus thymidine kinase genes was used to disrupt exons 8 and 9. The construct was electroporated into 129S1/Sv-p+ Tyr+ Kitl+ derived W9.5 embryonic stem (ES) cells, and correctly targeted ES cells were injected into C57BL/6 blastocysts. The resulting chimeric animals were crossed to C57BL/6N mice for at least 10 generations. Upon arriving at The Jackson Laboratory, the mice were crossed with C57BL/6J at least once to establish the colony.
SNP (single nucleotide polymorphism) analysis performed by The Jackson Laboratory revealed that this strain is a mixed genetic background (5 out of 27 markers were segregating for non-C57BL/6 alleles).
|Allele Name||targeted mutation 1, Richard A Flavell|
|Allele Type||Targeted (Null/Knockout)|
|Allele Synonym(s)||Mkk3-; MKK3 KO|
|Gene Symbol and Name||Map2k3, mitogen-activated protein kinase kinase 3|
|Strain of Origin||129S1/Sv-Oca2+ Tyr+ Kitl+|
|General Note||Homozygous mutant mice are viable and appear normal, healthy, and fertile with no defects in lymphocyte development (thymocytes, splenocytes, and bone-marrow derived dendritic cells). Compared to control sibs, however, macrophages and primary embryonic fibroblasts from mutant mice show reduced activation of p38 MAPK. Cytokine IL-12 (encoded for by Il12a and Il12b) is strongly reduced in mutant macrophages and dendritic cells. Mutant fibroblasts have a defective response to Tnf. Mutant mice also have defective T-helper cells with respect to the ability to produce Ifng in response to antigen stimulation of keyhole limpet hemocyanin (KLH) both in vitro and in vivo (J:54078, J:54309).|
|Molecular Note||A neomycin resistance cassette replaced a 1.5kb region that includes exons 8 and 9, which encode amino acids 217-221 of the protein. This region includes the sequences containing the dual phosphorylation sites (serine and threonine) that are required for activation of the protein. Northern blot and Western blot analyses did not detect expression from this allele in homozygous mutant mice.|
When maintaining a live colony, these mice are bred as homozygotes. The donating investigator reports that reproductive performance is poor for unknown reasons.
When using the Mkk3- mouse strain in a publication, please cite the originating article(s) and include JAX stock #006416 in your Materials and Methods section.