Mouse Models: SJL/J

SJL/J mice

Availability:
The Jackson Laboratory
Stock number: 000686
Strain information: http://jaxmice.jax.org/strain/000686.html
Phone: 800-422-MICE (800-422-6423)
610 Main Street, Bar Harbor, Maine 04609 USA

Development:
This inbred strain contains a naturally-occurring dysferlin mutation and was originally developed from three different sources of Swiss Webster mice.

Mutation:
Exon 45 (171 base pairs, aa1628-1685) is deleted in dysferlin mRNA, due to a mutation in the 3’ splice junction. This deletion removes part of the fifth C2 domain (C2E) of the protein.

Symptoms:
Mild myopathic lesions can be detected histologically around 1 month of age, with active myopathy by 6-8 months that primarily affects the proximal muscle groups and manifests as progressive muscle weakness. Muscular atrophy begins at 10 months, and by 16 months half of the muscle fibers are replaced by fat. There is dispute about whether young SJL mice (1-2 months) are stronger or weaker than control mice. The mice also have a high incidence of lymphoma, increased susceptibility to autoimmune diseases and viral infections, and extreme aggression in males, none of which are thought to be associated with dysferlin deficiency. They are also homozygous for a retinal degeneration allele (Pde6b gene).

Comparison with other disease strains:
Disease progression is similar to Dysf-/- (Campbell), Dysf-/- (Brown), and C57BL/10.SJL mice, and faster than in A/J mice. As in both A/J and Dysf-/- (Brown) mice, proximal muscles are more severely affected than distal muscles. The other symptoms, however, are not shared with the other dysferlin-deficient mice and are likely due to complicating genetic features of this strain.

Control strain(s):
No close matches

References:
Weller AH, et al. 1997. Spontaneous myopathy in the SJL/J mouse: pathology and strength loss. Muscle & Nerve 20:72-80.
Bittner RE, et al. 1999. Dysferlin deletion in SJL mice (SJL-Dysf) defines a natural model for limb girdle muscular dystrophy 2B. Nature Genetics 23:141-142.
Vafiadaki E, et al. 2001. Cloning of the mouse dysferlin gene and genomic characterization of the SJL-Dysf mutation. Neuroreport 12:625-629.