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  • PMID: 27538421 was deleted because it is a duplicate of PMID: 28172892
Hum Mol Genet. 2016 Oct 15;25(20):4494-4506. doi: 10.1093/hmg/ddw278.

Effect of genetic background on the phenotype of the Smn2B/- mouse model of spinal muscular atrophy.

Author information

1
Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada
2
University of Ottawa Centre for Neuromuscular Disease, Ottawa, Ontario, Canada
3
Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Ontario, Canada
4
Department of Medicine, University of Ottawa, Ottawa, Ontario, Canada

Abstract

Spinal muscular atrophy (SMA) is caused by mutations or deletions in the Survival Motor Neuron 1 (SMN1) gene in humans. Modifiers of the SMA symptoms have been identified and genetic background has a substantial effect in the phenotype and survival of the severe mouse model of SMA. Previously, we generated the less severe Smn2B/- mice on a mixed genetic background. To assess the phenotype of Smn deficiency on a pure genetic background, we produced Smn2B/2B congenic mice on either the C57BL/6 (BL6) or FVB strain background and characterized them at the 6th generation by breeding to Smn+/- mice. Smn2B/- mice from these crosses were evaluated for growth, survival, muscle atrophy, motor neuron loss, motor behaviour, and neuromuscular junction pathology. FVB Smn2B/- mice had a shorter life span than BL6 Smn2B/- mice (median of 19 days vs. 25 days). Similarly, all other defects assessed occurred at earlier stages in FVB Smn2B/-mice when compared to BL6 Smn2B/-mice. However, there were no differences in Smn protein levels in the spinal cords of these mice. Interestingly, levels of Plastin 3, a putative modifier of SMA, were significantly induced in spinal cords of BL6 Smn2B/- mice but not of FVB Smn2B/-mice. Our studies demonstrate that the phenotype in Smn2B/-mice is more severe in the FVB background than in the BL6 background, which could potentially be explained by the differential induction of genetic modifiers.

PMID:
28172892
PMCID:
PMC5409218
DOI:
10.1093/hmg/ddw278
[Indexed for MEDLINE]

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