Indeed, RT–PCR showed that zebrafish dnmt3ab was induced during heart regeneration and it is required for myocardial proliferation, and co-immunoprecipitation analysis showed that it directly interacted with Brg1 in 293T cells and H9C2 cardiomyocytes, consistent with the previous report that Brg1 and Dnmt3a interact in cancer cells38 and in hypertrophic cardiomyocytes39. The gene discussed is DNMT3A; the disease is cancer.