Lysates were clarified from sonicated nuclei and SET1A-DNA complexes were isolated with M2 beads (Sigma). For ChIP-seq libraries, 10 ng of input chromatin DNA or ChIP DNA were processed using the ThrePLEXTM-FD Prep kit (Rubcicon, 40048). Gel-purified ChIP-seq library DNA was further purified by phenol-chloroform extraction and ethanol precipitation, and processed for cluster generation, 15-cycle sequencing, and sequence analysis using Illumina Hiseq performed at the Beijing Genomics Institute (BGI)