Figure 2. Characterization of the modes of skeletal muscle atrophy in Smn^2B/− mice.

(a,b) Levels of Atrogin-1 and MuRF1 mRNA are not significantly changed at pre-symptomatic stage (P9) but are increased at symptomatic stage (P21) in the hindlimb (HL) of Smn^2B/− mice (p = 0.05 and 0.0067 respectively). (c,d) Levels of ubiquitinated proteins are unchanged at P9 but are significantly increased at P21 (p = 0.028). (e,f) Gabarapl1, CathepsinL and Bnip3 transcript levels are unchanged at pre-symptomatic stage (P9) but are significantly elevated at P21 in hindlimb muscles (p = 0.012, 0.066, and 0.012, respectively). (g,h) Protein expression of LC3-II and P62 is relatively unchanged at pre-symptomatic stage and LC3-II is significantly increased at symptomatic stage in hindlimb muscles of Smn^2B/− mice (p = 0.011). (N = 4 for a-f, N = 3 for g-h; p ≤ 0.05 for * and p ≤ 0.01 for **).