FIGURE 5.

Electroporation of PGC-1β in mouse muscle inhibits fiber atrophy, and both PGC-1α and PGC-1β decrease Atrogin1 promoter activity and NFκB activity. Frequency histograms (right) showing the distribution of cross-sectional areas of innervated (A) or 10-day denervated (B) muscle fibers of the TA. Muscles were electroporated with PGC-1β-IRES-GFP plasmids at the same time as denervation. Transfected fibers were identified in transverse sections by GFP expression (left). Scale bar represents 30 μm. Tibialis anterior (TA) or soleus muscles of adult mice were co-electroporated with the pRL-TK and Atrogin1 promoter (C) or NFκB binding (D) luciferase reporter plasmids together with GFP (control), PGC-1α, or PGC-1β plasmids. Five or ten days later, muscles were collected and luciferase activity was measured. *, p < 0.05 versus innervated GFP-transfected fibers; **, p < 0.05 versus denervated GFP-transfected fibers.