Changed NotchR and NotchR ligand expression and reduced NotchR signaling in HSACrePofut1FF muscles. (A and B) Relative expression of Notch receptor genes (NotchR1 to NotchR4), NotchR ligand genes (Dll1, Dll4, Jag1, and Jag2), and Fringe genes (Lfng, Mfng, and Rfng) in 2-month-old (A) and 17-month-old (B) HSACrePofut1FF, HSACre, and Pofut1FF skeletal muscles. (C) Relative gene expression of Hes1 and Hey1 at 2, 9, or 17 months of age. (D) Western blots of Gastroc whole-muscle lysate (left) and nuclear lysate (right) were probed with antibodies to NotchR1, NotchR3, β dystroglycan (βDG), α dystroglycan (αDG; probed using IIH6, specific for a glycosylation-specific epitope), Hes1, Hey1, lamin B1, or Notch R1 intracellular domain (NICD). Error bars in panels A to C show SEM (n = 6 to 9 samples per condition). *, P < 0.05; **, P < 0.01; ***, P < 0.001.