Luciferase reporter assays performed in cultured cardiomyocytes cotransfected with empty vector or TRα1 with empty vector or FOG-2 followed by treatment for 24h with vehicle or T3. Fold activation is expressed as relative luciferase activity normalized to either the vehicle-treated, empty vector control, or the vehicle-treated FOG-2 control when appropriate. Two-way ANOVA followed by Bonferroni was used for statistical analysis. (a) Co-transfection of FOG-2 expression plasmid abrogated TRα1 transactivation of the 0.6kb-SERCA2 luciferase reporter following T3-stimulation. * p<0.05, versus vector control (color-matched bar). (b) Assays using reporter constructs driven by tk alone or with three tandem repeats of TRE1 or TRE2 from the rat SERCA2 proximal promoter. TRα1 (shaded bars) silenced reporter activity in the absence of T3 and transactivated the reporter with T3 stimulation. FOG-2 abrogated T3-mediated TRα1 transactivation. * p<0.05, versus vector control (black bar). (c) Transactivation of 0.6kb-SERCA2 reporter by TRα1 with indicated doses of T3 (nM) was abrogated by FOG-2. * p<0.05, versus vector control (black bar). Data are from at least three independent experiments done in triplicate.