Similarly reduced proliferation in CMs was observed at the border zone of adult MI hearts (Figure 3G–J), and greater fibrotic scar size (Figure 3K) as well as deterioration of cardiac function (Figure 3L,M; Table S2, Supporting Information) in Foxp1CMTg compared with wild‐type littermates, suggesting that CM‐Foxp1 induced expression attenuates CM regenerative capability and deteriorates cardiac function in adult MI model. The gene discussed is FOXP1; the disease is myocardial infarction.