Most importantly, the activated COUP-TFII transgene increases COUP-TFII protein levels in cardiomyocytes (Supplementary Fig. 1d) to a similar extent as CnTg does (Supplementary Fig. 1c), which gives us confidence to use this model for dissecting the role of COUP-TFII in cardiomyopathy. This evidence concerns the gene NR2F2 and cardiomyopathy.