Plays a critical role in cardiac development (PubMed:30110327). Acts as a key epigenetic regulator of gene expression during cardiac development via its dual activities as a methyltransferase and negative regulator of HDAC1 (PubMed:30110327). Ubiquitously expressed in early embryos and becomes enriched in the developing heart at 48 hours post-fertilization. Mutants generated by CRISPR-Cas9-mediated gene editing exhibit severe cardiac malformations, including defects in left-right patterning and looping and hypoplastic ventricles. Belongs to the class V-like SAM-binding methyltransferase superfamily.