Mice hemizygous for this HSA-Cre79 transgene are viable, fertile, normal in size, and do not display any gross physical or behavioral abnormalities. These HSA-Cre79 transgenic mice have the cre recombinase gene driven by the human alpha-skeletal actin (HSA or ACTA1) promoter. Cre activity is restricted to adult striated muscle fibers and embryonic striated muscle cells of the somites and heart. When bred with mice containing a loxP-flanked sequence of interest, Cre-mediated recombination will result in striated muscle-specific deletion of the flanked genome. Specifically, these HSA-Cre79 (or ACTA1-Cre) transgenic mice were originally used to breed with mice heterozygous for a deletion of exon 7 and a loxP-flanked exon 7 mutation on homologous chromosomes of the Smn1 gene (see Stock No. 006138 or Stock No. 006146). The resulting offspring (heterozygous for the deletion in all cells and homozygous for the deletion in striated muscle cells) have extremely reduced lifespan characterized by progressive muscle necrosis and paralysis, and represent a model of spinal muscular atrophy (SMA).
Additional SMA strains expressing cre in neurons are available as well (see Stock No. 005938, Stock No. 006297, and Stock No. 006663).
HSA-Cre79 transgenic mice are also available on a different genetic background (see Stock No. 006139). In an attempt to offer alleles on well-characterized or multiple genetic backgrounds, alleles are frequently moved to a genetic background different from that on which an allele was first characterized. It should be noted that the HSA-Cre79 phenotype could vary from that originally described on a mixed genetic background. We will modify the strain description if necessary as published results become available.
Importation of this model was supported by the Spinal Muscular Atrophy Foundation. Creation and development was supported by the National Institute of Health and Medical Research of France (Inserm) and the Association Française contre les Myopathies (AFM). An additional help was provided by Families of SMA (U.S.A.) and Andrew’s Buddies (U.S.A.).
