The CA46 cells' ChIP-seq experiments with spike-in control was referred to the manufacturer's instruction (Active Motif). In this experiment, the DNA fragments were sonicated between 200bp to 500bp. For H3K4me3 ChIP and a Drosophila-specific antibody (Active Motif 61686), 1.5 X 107 CA46 cells were used. As to RNA-seq, total RNA was extracted using TRIZOL Reagent (Life technologies) following the manufacturer's instructions and checked for a RIN number to inspect RNA integrity by an Agilent Bioanalyzer 2100.Qualified total RNA was further purified by RNeasy micro kit and RNase-Free DNase Set. Sequencing libraries were generated using NEBNext® Ultra™ RNA Library Prep Kit for Illumina® (NEB, USA) following manufacturer's recommendations and index codes were added to attribute sequences to each sample ChIP-sequencing libraries were prepared according to generated using NEBNext® Ultra™ IIDNA Library Prep Kit (#E7645). RNA-sequencing libraries were generated using NEBNext® Ultra™ RNA Library Prep Kit for Illumina® (NEB, USA) following manufacturer's recommendations and index codes were added to attribute sequences to each sample.