PRC2 directly methylates GATA4 and represses its transcriptional activity

Polycomb-repressive complex 2 (PRC2) promotes tissue-specific differentiation by depositing trimethylated histone H3 Lys 27 (H3K27me3) epigenetic marks to silence ectopic gene expression programs. Here, we show that EZH2, the catalytic subunit of PRC2, is required for cardiac morphogenesis. Both in vitro and in fetal hearts, EZH2 interacted with cardiac transcription factor GATA4 and directly methylated it at Lys 299. PRC2 methylation of GATA4 attenuated its transcriptional activity by reducing its interaction with and acetylation by p300. Our results reveal a new mechanism of PRC2-mediated transcriptional repression in which PRC2 methylates a transcription factor to inhibit its transcriptional activity.