B6.129X-Gusb^tm3Sly/J

Stock number: 005644
Research areas: Developmental Biology Research, Internal/Organ Research, Metabolism Research

Description

Homozygous mice for this targeted mutation in beta glucuronidase (Gusb) exhibit growth retardation, shortened extremities, and facial dysmorphism. This model has increased urinary glycosaminoglycan and secondary elevation of other lysosomal storage enzymes. This strain represents a model of human GUS deficiency characterized by the most prevalent human mutation, L176F, and is associated with mild Mucopolysaccharidosis type VII (MPS VII or Sly Syndrome).

Detailed description

Homozygous mice are viable but infertile. Fertility can be restored with enzyme replacement therapy. Less than 1% residual enzyme activity is observed. Homozygous mice are indistinguishable from wild type mice at birth, but show distinct growth retardation, shortened extremities, and facial dysmorphism observable at three months with a moderate increase in severity with age. Long bones of the lower extremities are shortened, broad, and sclerotic. Compared to wild-type, this model has increased urinary glycosaminoglycan and secondary elevation of other lysosomal storage enzymes. Further, homozygous mice show abundant lysosomal storage in liver, kidney, leptomeningeal cells, cornea, and retinal pigment epithelium. The phenotype exhibited by this mutant mouse strain is less severe than that observed in a similarly constructed mutant (Stock No. 005643) which bears a E536A point mutation. This strain represents a model of human GUS deficiency characterized by the most prevalent human mutation, L176F, and is associated with mild Mucopolysaccharidosis type VII (MPS VII or Sly Syndrome).

Development

A targeting vector containing exons 1-10 (12.4 kb) of the targeted gene, a loxP-flanked neomycin resistance gene between exons 9 and 10, and herpes simplex virus thymidine kinase gene for selection of properly transfected cells was used in the creation of this mutant. A mutagenic primer was used to introduce a leucine to phenylalanine substitution at residue 175 (L175F) in exon 2 of the targeting vector. The construct was electroporated into the 129X1/SvJ-derived embryonic stem (ES) cell line RW-4. Correctly targeted ES cells were injected into C57BL/6J blastocysts and the resulting chimeric males were backcrossed for germ-line transmission to C57BL/6J females. Offspring were mated with Cre-expressing C57BL/6J to remove the neomycin resistance gene. The neo-excised heterozygotes were backcrossed to C57BL/6J for ten generations.

Allele

Symbol: Gusb^tm3Sly
Name: targeted mutation 3, William S Sly
MGI accession ID: MGI:2451061
Generation method: Targeted
Attributes: Humanized sequence
Synonyms: Gus^tm(L175F)Sly
Marker symbol: Gusb
Marker name: glucuronidase, beta
Chromosome: 5
Strain of origin: 129X1/SvJ
Molecular note: Site directed mutagenesis was used to introduce a leucine to phenylalanine subsitution at residue 175 (L175F) of exon 2. This mutation corresponds to L176F, the most common mutation found in human GUS deficiency.