Figure 5.

Specificity of NRG-1-induced NMJ gene expression via PGC-1α. (A,B) Primary muscle cells were isolated from control and PGC-1α knockout animals. After differentiation into myotubes, cells were treated with vehicle (PBS) or 5 nM recombinant NRG-1 for 48 h. RNA was isolated from harvested cells and relative gene expression levels of NMJ genes (A) and other PGC-1α target genes (B) were determined by real-time PCR. (*) p < 0.05 between vehicle and NRG-1 treated cells. The bars depict average gene expression normalized to 18S rRNA levels, with the error bars representing standard deviations. (C,D) C2C12 myoblasts were transfected with a reporter plasmid containing the ERRα promoter and expression plasmids for PGC-1α, GABPA and GABPB1 (called GABP), ERRα, and the phosphorylation-deficient PGC-1α 3A. The cells were subsequently differentiated for 2 d and harvested, and luciferase activity controlled by PGC-1α and GABP (C) and PGC-1α and ERRα (D) was measured. The bars depict average luciferase expression normalized to β-galactosidase activity, with the error bars representing standard deviations.