Figure 4
From: Regulation of skeletal muscle growth by the IGF1-Akt/PKB pathway: insights from genetic models
Myofiber hypertrophy or atrophy induced by transfection of skeletal muscle with mutants of Akt or FoxO. (A) Regenerating rat soleus muscle transfected with plasmid coding for constitutively active Akt1 linked to a hemagglutinin (HA) epitope. Muscle examined 7 days after transfection; section stained for the HA tag. Note the striking hypertrophy of labeled myofibers compared with untransfected neighbouring fibers. Modified from [69]. (B,C) Adult mouse tibialis anterior muscle transfected by electroporation with plasmid coding for constitutively active Ha-tagged FoxO3. Muscle examined 14 days after transfection; section stained for the HA tag. Note the striking atrophy of labeled myofibers compared with untransfected neighboring fibers. A phase-contrast image of the same field is shown in the right panel. Modified from [91].