Effects of ERRβ knockdown on gene expression. Cardiomyocytes were infected with adenovirus expressing either ERRβ-shRNA or Scr-shRNA. After 48 h of incubation, cardiomyocytes were electrically stimulated to contract in hypoxia over 24 h. Contracting cardiomyocytes in normoxia were used as baseline controls. A. Fold changes in levels of ERR mRNA isoforms. Values are the mean ± SE, *p<.05, n=4 experiments. B. Fold changes in levels of PGC-1 mRNA isoforms. Values are the mean ± SE, *p<.05, n=5 experiments.