Figure 3. β1-syntrophin mRNA and protein expression.

A: The mRNA levels in from the gastrocnemius muscle tissues of wt and mdx mice of different ages (30 d, 30-day-old mice; 5 m: five-month-old mice) were determined by qRT-PCR and calculated by the comparative Ct method (2^−ddCt). The Ct values from each gene are normalized to the Ct value of GAPDH in the same RNA sample. The mRNA levels in the mdx samples are expressed as fold change compared to those in the wt samples. All values represent the mean ± SD of four experiments performed on different RNA preparations of the muscle tissues from wt and mdx mice (see Method). Statistical significance was determined as *P<0,05 (P = 0,012 as measured by the Mann-Whitney test). B: Total protein extracts from the gastrocnemius muscles of wt and mdx mice were resolved by SDS-PAGE and probed with β1-syntrophin antibodies. A representative western blot is shown. The graph values represent the mean ± SD of the densitometric analyses from four independent experiments with different animal samples (see Methods). Data are presented as the percentage of protein in mdx mice compared to that in wt mice, normalized to endogenous actin expression level. *P<0,05 versus wt (P = 0,002 as measured by the Mann-Whitney test). C: Sections of the gastrocnemius muscles of wt and mdx adult mice were probed with an anti-β1-syntrophin antibody and visualized using a secondary antibody coupled to a fluorescent marker, FITC. A representative of the two performed analyses on different animals is shown.