The homogenized and cleared fly heads were sonicated to a length between 200~500 bp. The sheared chromatin was precleared with Protein A beads then incubated with 5ml of antibody and 30ml of Protein A beads at 4°C for 3 hours. After thorough washing, the samples were eluted by 10% SDS and Protease K at 65°C for 8 hours. The eluted chromatin was extracted by phenol-chloroform clean-up followed by ethanol precipitation. RNA libraries were prepared for sequencing using standard Illumina protocols