These Idua-W392X mice carry a nonsense mutation of Idua (alpha-L-iduronidase) that is analogous to the W402X mutation commonly found in patients with Hurler syndrome and are valuable for evaluation of therapeutic treatments mucopolysaccharidosis type I-Hurler (MPS I-H).
Kim M. Keeling, University of Alabama at Birmingham
These mice carry a nonsense mutation at Idua codon W392, (Idua-W392X), which corresponds to the human IDUA-W402X mutation that prematurely terminates protein synthesis and is commonly found in patients with mucopolysaccharidosis type I-Hurler (MPS I-H) syndrome. Deficiency of the alpha-L-iduronidase enzyme causes this lysosomal storage disease. No alpha-L-iduronidase activity is detected in brain and liver tissues from homozygous mice aged 5, 10 and 30 weeks. Although mice that are homozygous for this mutation are viable and fertile, they have a median lifespan of 69 weeks. Homozygotes exhibit a progressive increase in urinary excretion of glycosaminoglycans (GAGs), and progressive accumulation of GAGs in tissues. The level of steady state Idua mRNA is reduced 30-50%. Histological analysis reveals progressive accumulation of lysosomal storage inclusions in the cytoplasm of Purkinje cells, medullar neurons, as well as infiltration of foamy macrophages that increases with age. Thickening of the zygomatic arch and femur is detected at 15 weeks of age by radiography, and increases at 35 weeks of age. At 35 weeks of age femur bone mineral density is increased and percent body fat decreased.
A targeting vector containing sequence with a single amino acid substitution for a nonsense
mutation at codon W392 (by site-directed mutagenesis), a loxP site flanked NEO cassette was used to insert the W392X point mutation in exon 9 and the floxed NEO between exons 8
and 9. The construct was electroporated into unspecified 129/Sv derived embryonic stem (ES) cells. Correctly targeted ES cells were injected into C57BL/6J blastocysts. The resulting chimeric animals were crossed to C57BL/6J mice. The mice were then crossed to C57BL/6-Tg(Zp3-cre)93Knw/J (Stock No. 003651) to remove the floxed NEO cassette. The mice were backcrossed to C57BL/6J for 8 generations.
|Allele Name||targeted mutation 1, Kim M Keeling|
|Gene Symbol and Name||Idua, iduronidase, alpha-L|
|Promoter||Idua, iduronidase, alpha-L, mouse, laboratory|
|Strain of Origin||129/Sv|
|Molecular Note||Nucleotide substitutions (TGG to TAG) were introduced into exon 9 that result in the amino acid substitution of tryptophan with a stop at position 392 (W392X). A floxed neo cassette inserted between exons 8 and 9 was removed by cre mediated recombination leaving a single loxP site. The mutation mimicks one identified in patients with mucopolysaccharidosis type I-Hurler (MPS I-H), also known as Hurler syndrome. RT-PCR confirmed a 30% to 50% reduction in steady-state transcript levels.|
|Mutations Made By|| |
Kim Keeling, University of Alabama at Birmingham
When maintaining a live colony, these mice can be bred as homozygotes; however, homozygotes have a median lifespan of 69 weeks.
When using the Idua-W392X mouse strain in a publication, please cite the originating article(s) and include JAX stock #017681 in your Materials and Methods section.