Transgenic mice expressing tunable levels of DUX4 develop characteristic facioscapulohumeral muscular dystrophy-like pathophysiology ranging in severity

摘要

Transgene map and FSHD-like model generation. The synthesized FLExDUX4 (FLExD) transgene, flanked by heterologous lox sites (loxP and lox511), was inserted in the antisense orientation to the promoter and maintains the intron/exon structure and mRNA regulatory features, including the PAS and DAE, of the human chromosome 4q35 gene. When crossed with mice, the bi-transgenic offspring have the capacity for dosage-dependent, TMX-inducible unidirectional recombination of the transgene, resulting in DUX4 expression exclusively in skeletal muscle and transcribed from the promoter, processed, and terminated in exon 3 using the PAS. Genomic PCR indicating percent transgene recombination in different muscles from mice and bi-transgenic mice with no TMX or 3 days after a single IP injection of 5 mg/kg TMX (low), or two IP injections of 10 mg/kg TMX (high). TA, tibialis anterior; Sol, soleus; GA, gastrocnemius; Qua, quadriceps; Diaph, diaphragm