S2 cells were cross-linked for 15 min at 37℃ in 1 ml of 1% formaldehyde in PBS buffer. The cross-linking was stopped by adding Glycine to a final concentration of 0.125M. Cells were sonicated with a Bioruptor sonicator to yield genomic DNA fragments with an average size of about 200 bp. protein-DNA complexes were isolated with Lola antibody. Genomic DNA was purified with a DNA purification kit (QIAGEN). Libraries were prepared using standard Illumina protocols.