Active site mutant transgene confers tolerance to human beta-glucuronidase without affecting the phenotype of MPS VII mice.
Mucopolysaccharidosis type VII (MPS VII; Sly syndrome) is an autosomal recessive lysosomal storage disorder due to an inherited deficiency of beta-glucuronidase. A naturally occurring mouse model for this disease was discovered at The Jackson Laboratory and shown to be due to homozygosity for a 1-bp deletion in exon 10 of the gus gene. The murine model MPS VII (gus(mps/mps)) has been very well characterized and used extensively to evaluate experimental strategies for lysosomal storage diseases, including bone marrow transplantation, enzyme replacement therapy, and gene therapy. To enhance the value of this model for enzyme and gene therapy, we produced a transgenic mouse expressing the human beta-glucuronidase cDNA with an amino acid substitution at the active site nucleophile (E540A) and bred it onto the MPS VII (gus(mps/mps)) background. We demonstrate here that the mutant mice bearing the active site mutant human transgene retain the clinical, morphological, biochemical, and histopathological characteristics of the original MPS VII (gus(mps/mps)) mouse. However, they are now tolerant to immune challenge with human beta-glucuronidase. This "tolerant MPS VII mouse model" should be useful for preclinical trials evaluating the effectiveness of enzyme and/or gene therapy with the human gene products likely to be administered to human patients with MPS VII.
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Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, 1402 South Grand Boulevard, St. Louis, MO 63104, USA. slyws@sku.edu
Vogler
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Grubb
J H
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Zhou
M
M
Jiang
J
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Zhou
X Y
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Tomatsu
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S
Bi
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Snella
E M
EM
D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D017931:DNA Primers; D005966:Glucuronidase / Q000235:genetics / Q000378:metabolism*; D007108:Immune Tolerance / Q000235:genetics*; D051379:Mice; D008822:Mice, Transgenic; D016538:Mucopolysaccharidosis VII / Q000201:enzymology / Q000235:genetics / Q000276:immunology / Q000473:pathology*; D009154:Mutation; D010641:Phenotype; D019076:Transgenes
D017931:DNA Primers; D005966:Glucuronidase