B6.Cg-Sgca^tm1Kcam Tg(Ckm-SGCE)1Kcam/J

Stock number: 009651
Research areas: Mouse/Human Gene Homologs, Neurobiology Research

Description

This strain carries both a mouse alpha-sarcoglycan (Sgca) targeted mutation and a human epsilon-sarcoglycan (SGCE) transgene. Mice display no overt phenotype with normal behavior and normal muscle force generation. After mild exercise, the compound mutants show an exaggerated fatigue response. This strain may be useful in studies of muscular dystrophy and exercise-induced fatigue.

Detailed description

Homozygous alpha-sarcoglycan targeted mutant mice develop a progressive pathology characteristic of limb-girdle muscular dystrophy type 2D starting at one week of age. Necrosis, regeneration, central nucleation, atrophy, hypertrophy, fiber splitting and endomysial fibrosis are observed in their muscle.

When combined with a human epsilon-sarcoglycan transgene driven by a mouse muscle creatine kinase promoter specific to skeletal and heart muscle (as in this compound mutant strain) mice display no overt phenotype with normal behavior and normal muscle force generation. After mild exercise, the compound mutants show an exaggerated fatigue response. Biochemically, the mice show normal levels of nNOS (NOS1) in muscle homogenates, but variable levels in membrane fractions. By immunofluorescence, nNOS (NOS1) is not localized to all muscle membrane fibers.

Development

The Sgca targeted allele was made by replacing exons 2 and 3 of the gene with a neomycin resistance cassette. The construct was electroporated into (129X1/SvJ x 129S1/Sv)F1- Kitl⁺-derived R1 embryonic stem (ES) cells. The line was backcrossed five times to C57BL/6 by the donating laboratory.

The mouse muscle creatine kinase promoter specific for skeletal and cardiac muscle drives expression of the full-length human epsilon-sarcoglycan cDNA in the transgenic portion of this strain. This is Line 1 of the transgenic line. The transgenic vector was introduced to B6SJLF1 embryos. The mutation was backcrossed twice to C57BL/6 then crossed to the Sgca line mentioned above for 13 generations by the donating laboratory.

Allele

Symbol: Tg(Ckm-SGCE)1Kcam
Name: transgene insertion 1, Kevin Campbell
MGI accession ID: MGI:3841390
Generation method: Transgenic
Attributes: Inserted expressed sequence; Humanized sequence
Marker symbol: Tg(Ckm-SGCE)1Kcam
Marker name: transgene insertion 1, Kevin Campbell
Chromosome: UN
Strain of origin: (C57BL/6 x SJL)F1
Expressed genes: SGCE,sarcoglycan epsilon,human
Molecular note: The mouse muscle creatine kinase promoter specific for skeletal and cardiac muscle drives expression of the full-length human epsilon sarcoglycan in this transgene construct.

Allele

Symbol: Sgca^tm1Kcam
Name: targeted mutation 1, Kevin P Campbell
MGI accession ID: MGI:1934922
Generation method: Targeted
Attributes: Null/Knockout
Marker symbol: Sgca
Marker name: sarcoglycan, alpha (dystrophin-associated glycoprotein)
Chromosome: 11
Strain of origin: (129X1/SvJ x 129S1/Sv)F1-Kitl⁺
Molecular note: Replacement of 902 bp including exons 2 and 3 with a neomycin cassette. No mRNA was detectable in Northern blots of total RNA derived from skeletal muscle tissue of homozygous mutants, and no protein was detected in Western blots in membrane enriched preparations of skeletal muscle.