Molecular characterization of the T153R β-SG KI mouse model (n = 4 to 6 per group).

(A) mRNA expression for α-SG, β-SG and γ-SG as defined by qPCR. No significant decrease of gene expression in the T153R β-SG KI mice was observed whereas levels of α-SG and γ-SG are substantially reduced in α-SG KO. (B) Protein expression of β-SG was evaluated by Western-blot performed on muscles sections form WT, α-SG KO and T153R β-SG KI mice at 4 months of age. The β-SG protein level was unaffected in T153R β-SG KI mouse, whereas it was highly decreased in α-SG KO mice. Alpha-actinin was used as loading control. (C) The localization of several DGC members was studied by immunostaining on muscles sections form WT, α-SG KO and T153R β-SG KI mice at 4 months of age. Immunostaining at 9 months of age is also shown for T153R β-SG KI mice. The T153R β-SG mutant protein was present at the muscle fiber membrane at 4 and 9 months and did not seem to perturb the DGC assemblage as showed by the correct membrane localization of dystrophin and α-SG. Size bar: 50μm.