Normal expression of myofilament protein isoforms in soleus muscle of infantile MGsKO mice. SDS-PAGE, glycerol-SDS gel, and Western blots showed that days 1, 7, and 21 postnatal MGsKO and control mouse soleus muscles had similar expression and developmental patterns of MHC, TnI, and TnT isoforms. n = 3 mice per time point in each group.