Human Molecular Genetics, 2003, Vol. 12, No. 9 961-973
DOI: 10.1093/hmg/ddg119
© 2003 Oxford University Press
Production of MPS VII mouse (Gustm(hE540A·mE536A)Sly) doubly tolerant to human and mouse ß-glucuronidase
1Edward A. Doisy Department of Biochemistry and Molecular Biology and 2Department of Pathology, Saint Louis University School of Medicine, St Louis, MO 63104, USA and 3Department of Pediatrics, Gifu University School of Medicine, Gifu 500, Japan
Received December 11, 2002; Revised February 21, 2003; Accepted March 3, 2003
Mucopolysaccharidosis VII (MPS VII, Sly syndrome) is an autosomal recessive lysosomal storage disease caused by ß-glucuronidase (GUS) deficiency. A naturally occurring mouse model of that disease has been very useful for studying experimental approaches to therapy. However, immune responses can complicate evaluation of the long-term benefits of enzyme replacement or gene therapy delivered to adult MPS VII mice. To make this model useful for studying the long-term effectiveness and side effects of experimental therapies delivered to adult mice, we developed a new MPS VII mouse model, which is tolerant to both human and murine GUS. To achieve this, we used homologous recombination to introduce simultaneously a human cDNA transgene expressing inactive human GUS into intron 9 of the murine Gus gene and a targeted active site mutation (E536A) into the adjacent exon 10. When the heterozygote products of germline transmission were bred to homozygosity, the homozygous mice expressed no GUS enzyme activity but expressed inactive human GUS protein highly and were tolerant to immune challenge with human enzyme. Expression of the mutant murine Gus gene was reduced to about 10% of normal levels, but the inactive murine GUS enzyme also conferred tolerance to murine GUS. This MPS VII mouse model should be useful to evaluate therapeutic responses in adult mice receiving repetitive doses of enzyme or mice receiving gene therapy as adults. Heterozygotes expressed only 9.5–26% of wild-type levels of murine GUS instead of the expected 50%, indicating a dominant-negative effect of the mutant enzyme monomers on the activity of GUS tetramers in different tissues. Corrective gene therapy in this model should provide high enough levels of expression of normal GUS monomers to overcome the dominant negative effect of mutant monomers on newly synthesized GUS tetramers in most tissues.
* To whom correspondence should be addressed at: Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, 1402 South Grand Boulevard, St Louis, MO 63104, USA. Tel: +1 3145778131; Fax: +1 3147761183; Email: slyws{at}slu.edu
CiteULike 
Connotea 
Del.icio.us What's this?
This article has been cited by other articles:
|
|
 |
|
  S. Tomatsu, M. Gutierrez, T. Nishioka, M. Yamada, M. Yamada, Y. Tosaka, J. H. Grubb, A. M. Montano, M. B. Vieira, G. G. Trandafirescu, et al. Development of MPS IVA mouse (Galnstm(hC79S{middle dot}mC76S)slu) tolerant to human N-acetylgalactosamine-6-sulfate sulfatase Hum. Mol. Genet., November 15, 2005; 14(22): 3321 - 3335. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. Tomatsu, K. O. Orii, R. E. Fleming, C. C. Holden, A. Waheed, R. S. Britton, M. A. Gutierrez, S. Velez-Castrillon, B. R. Bacon, and W. S. Sly Contribution of the H63D mutation in HFE to murine hereditary hemochromatosis PNAS, December 23, 2003; 100(26): 15788 - 15793. [Abstract] [Full Text] [PDF]
|
|