These Prf1 knock-out mice exhibit a delay and decrease of diabetes disease incidence compared to NOD wildtype mice.
Dr. David Kagi, Ontario Cancer Institute, Rm8-622
Mice homozygous for the Prf1tm1Sdz targeted mutation are viable and fertile. Homozygous mutant mice on an autoimmune type 1 diabetes prone NOD background have normal numbers of CD4- CD8+ T cells in the spleen. CD4- CD8- expressing T lymphocytes were also normal. NOD mice show a progressive infilitatraion of mononuclear cells into pancreatic islets beginning around 5 weeks of age. NOD wildtype and PRF1 deficient mice show similar development of insulititis. However, disease incidence was decreased from 77% in wildtype females to 16% in homozygotes. The onset of disease was also delayed from a median of 19 weeks to 39.5 weeks of age. These results show the importance of perforin-mediated cytotoxic T cells in development of autoimmune diabetes. (Kagi et al., 1994; Kagi et al., 1997.)
The endogenous perforin (Prf1) gene was disrupted by the insertion of a targeting construct into the third exon of the gene without deletion of coding sequence. The 3.3 kb targeting construct consisted of exon 3, a portion of the preceding intron, and a selective neomycin resistance cassette. Positive BL/6III ES cells (derived from C57BL/6), as determined by Southern Blot analysis, were injected into BALB/c blastocysts. Chimeric mice were bred with C57BL/6 to create individuals heterozygous for the disrupted Prf1 gene, which were then intercrossed to obtain homozygous mutant mice on the C57BL/6 background (Stock# 002407). Homozygous mutant mice were confirmed to lack the PRF1 protein by the absence of PRF1 antibody staining of stimulated spleen cells. The mutation was transferred to the NOD background via at least seven backcrosses after which heterozygous individuals were intercrossed to produce homozygous mutant mice on the NOD background. This strain has been maintained by sibling mating homozygous mice. (Kagi et al., 1994; Kagi et al., 1997.)
|Allele Name||targeted mutation 1, Sandoz Pharmaceuticals|
|Allele Type||Targeted (Null/Knockout)|
|Allele Synonym(s)||P0; perf-; perforin-; perforin 0; Pfn-; pfp-; Pfptm1Sdz; pfpKO; pko; Prf-; Prf1-; Prf1tm/Sdz; prf1tm1|
|Gene Symbol and Name||Prf1, perforin 1 (pore forming protein)|
|Strain of Origin||C57BL/6J|
|Molecular Note||A neomycin selection cassette was inserted into exon 3. RT-PCR analysis on RNA derived from homozygous mice demonstrated that an abnormal transcript was produced from this allele. However, immunocytochemistry experiments on activated spleen cells derived from homozygous mice confirmed that no detectable protein was made from this allele.|
|Mutations Made By|| |
Dr. Birgit Lederman, University of Zurich
Homozygotes are viable and fertile. When maintaining a live colony, homozygous mice may be bred together. The breeding facility should be free of viruses and pinworms as both inhibit the development of diabetes in NOD. The expected coat color from breeding is albino.
When using the NOD.Pfp mouse strain in a publication, please cite the originating article(s) and include JAX stock #003505 in your Materials and Methods section.