Because intraperitoneal injections of tamoxifen have been associated with Cre-driven cardiomyopathy in similar mouse models (Lexow et al., 2013), the ArntΔEC, ERT2 mice were orally treated with tamoxifen for 2 weeks via our published protocols (Ichikawa et al., 2014; Wu et al., 2014). The gene discussed is MAPK3; the disease is cardiomyopathy.