1. Genetic strategies used to create a mouse model of SMA
Genetic strategies used to create a mouse model of SMA. A, Mutant mice carrying a heterozygous deletion of Smn exon 7 (left) have been crossed with a mouse line carrying, in addition to the heterozygous deletion of Smn exon 7, a 115-kb human genomic DNA transgene containing SMNc (Hu-SMNc), part of NAIP (NAIPp), and H4F5 (right). Boxes indicate the exons and black solid line indicates the transgene. Mice carrying both the homozygous deletion of SMN exon 7 and the human transgene display abnormal phenotypes. B, Mutant mice carrying a heterozygous deletion of Smn from exon 2 (left) have been crossed with a mouse line carrying, in addition to the same Smn mutation, a human genomic DNA transgene containing SMNc only (Hu-SMNc, right). Mice carrying both the homozygous deletion of Smn and the human SMNc gene transgene display abnormal phenotypes. C, Mutant mice carrying two loxP sites flanking Smn exon 7 (left, SMNF7) have been crossed with a mouse line carrying, in addition to the heterozygous deletion of Smn exon 7 (SMNΔ7), a transgene expressing the Cre recombinase in neurons (indicated by N-Cre, right). The mutant mice carrying the SMNF7/SMNΔ7 genotype and the N-Cre transgene display an abnormal phenotype. In neuronal tissues, Cre-mediated deletion of the SMNF7 allele leads to a homozygous deletion of Smn exon 7 (Cre+). In nonneuronal tissues, SMNF7 remains intact because the Cre recombinase is not expressed (Cre−). LoxP sites are indicated by arrows. Human SMNc transgene or conditional targeting of SMN restricted to neurons are able to avoid early embryonic lethality.
Source: Spinal Muscular Atrophy, The Online Metabolic and Molecular Bases of Inherited Disease
Citation: Valle D, Beaudet AL, Vogelstein B, Kinzler KW, Antonarakis SE, Ballabio A, Gibson K, Mitchell G. The Online Metabolic and Molecular Bases of Inherited Disease; 2014 Available at: Accessed: October 04, 2017
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