Mice homozygous for the dystrophia-muscularis spontaneous mutations (Lama2dy and Lama2dy-2J) are characterized by progressive weakness and paralysis beginning at about 3 1/2 weeks of age. The hindlimbs are affected first, later the axial and forelimb musculature. Death usually occurs before 6 months of age, and mutant mice are usually sterile. Skeletal muscle shows degenerative changes with proliferation of sarcolemmal nuclei, increase in amount of interstitial tissue, and size variation among individual muscle fibers. In the dorsal and ventral roots of the peripheral nerves, both spinal and cranial, Schwann cells fail to separate and ensheathe axons so that groups of closely apposed naked axons, normally seen only in early stages, persist into adulthood. In the rest of the PNS, the basement membrane of Schwann cells is interrupted by gaps, the internodal gap in the nodes of Ranvier is lengthened, and there is delayed onset of myelination with fewer myelinated axons and shorter internode length.
The mutation first appeared in 1951 in E.S. Russell’s colony of 129/Re mice at The Jackson Laboratory. Embryos produced by crossing 129P1/ReJ-Lama2dy/J males with 129P1/ReJ females were cryopreserved in 1992
|Allele Name||dystrophia muscularis|
|Gene Symbol and Name||Lama2, laminin, alpha 2|
|Strain of Origin||129P1/Re|
|General Note||This mutation arose spontaneously in the 129/Re inbred strain at The Jackson Laboratory in 1951.|
|Molecular Note||Analysis of Lama2 expression of dystrophic dy mice revealed a specific deficiency of this mRNA in skeletal muscle, cardiac muscle, and peripheral nerve.|
When using the dystrophia muscularis mouse strain in a publication, please cite the originating article(s) and include JAX stock #000641 in your Materials and Methods section.