ZNF281 interacts with GATA4 to synergistically activate cardiac genes. (A) Coimmunoprecipitation assays were performed using HEK293 cells transfected with equal amounts of plasmid DNA encoding Myc-tagged GATA4, HAND2, MEF2C, or TBX5 and/or Flag-tagged ZNF281. (IP) Immunoprecipitation; (IB) immunoblot. (B) Heat maps showing ChIP-seq (chromatin immunoprecipitation [ChIP] followed by high-throughput sequencing) data for H3K27ac in adult mouse hearts and ZNF281 and GATA4 binding in reprogrammed TTFs at ±5 kb around the peak center. ChIP-seq experiments were performed using TTFs infected with 6F for 2 d. (C) ZNF281-binding motif enriched within ZNF281-binding peaks. (D) GATA4-binding motif enriched within GATA4-binding peaks. (E) Venn diagram showing the number of overlapping peaks between heart H3K27ac, ZNF281, and GATA4. (F) Total number of peaks identified by ChIP-seq.