Npc1tm(I1061T)Dso mutant mice possess loxP sites flanking exons 14-20 of the Niemann-Pick type C1 (Npc1) gene, as well as the I1061T missense mutation commonly found in humans with the cholesterol–sphingolipid lysosomal storage disorder, Niemann-Pick type C1 (NPC1) disease.
Daniel S. Ory, Washington University School of Medicine
Npc1tm(I1061T)Dso mutant mice possess loxP sites flanking exons 14-20 of the Niemann-Pick type C1 (Npc1) gene. They also contain the I1061T missense mutation in exon 21, which is commonly found in humans with Niemann-Pick type C1 (NPC1) disease. NPC1 is a lysosomal membrane protein that mediates intracellular cholesterol trafficking. Mutations in Npc1 are responsible for Niemann-Pick type C (NPC) disease, a fatal neurodegenerative disease caused by a defect in cholesterol–sphingolipid lysosomal storage. Niemann-Pick Type C1 (NPC1) disease is a rare form of the disease and is characterized by ataxia, motor impairment, progressive intellectual decline, and dementia. Mice that are homozygous for this allele are viable with an average lifespan of 125 days. At 10 weeks of age mice begin to lose weight compared to controls and heterozygous littermates. Weight loss is progressive during later stages of disease. At 8 weeks of age mice exhibit visible resting tremors, and by 12 weeks the mice are no longer able to maintain balance on a rotating rod. NPC1I1061T protein has a reduced half-life in vivo, consistent with protein misfolding and rapid endoplasmic reticulum-associated degradation. Mice also showed progressive Purkinje cell degeneration in the cerebellum
When bred to mice that express tissue-specific Cre recombinase, resulting offspring will have exons 14-20 deleted in the cre-expressing tissues, creating a Npc1 null mouse model. Homozygotes KO mice typically exhibit lysosomal storage of non-esterified cholesterol, neurodegeneration, ataxia, presence of foam cells, sterility, and a shortened lifespan.
A targeting vector was designed to insert a loxP site upstream of exon 14, and a frt-flanked neomycin resistance (neo) cassette followed by a second loxP site downstream of exon 20 of the Niemann-Pick type C1 (Npc1) gene. A T3179C point mutation was introduced in exon 21, amino acid 1061, resulting in a missense mutation, I1061T, commonly found in humans with Niemann-Pick type C1 (NPC1) disease. The construct was electroporated into 129 embryonic stem (ES) cells. Correctly targeted ES cells were injected into C57BL/6 blastocysts and resulting chimeric mice were bred with to C57BL/6J mice for 5 generations. Upon arrival, mice were bred to C57BL/6J inbred mice (Stock No. 000664) for at least one generation to establish the colony.
Currently there are no related genes or alleles for this strain.
When maintaining a live colony, heterozygous mice may be bred together. Homozygous mice have reduced lifespan, with an average survival of 125 days. The donating investigator has not attempted to breed homozygous mice.
When using the Npc1tm(I1061T)Dso mouse strain in a publication, please cite the originating article(s) and include JAX stock #027704 in your Materials and Methods section.