We adapted a recently published protocol (Simigdala et al.). 5 ml of larvae were disrupted using the gentleMACS dissociator (Milteny). The disrupted material was crosslinked in 1% formaldehyde for 10 min at room temperature. Crosslinking was stopped and formaldehyde quenched with 125 mM glycine for 5 min and washed two times in PBS (PBS Dulbecco, L 182-50, Biochrom AG). The material was separated by a gradient of 10% Ficoll (Ficoll PM 400, 17 0300 50, GE Healthcare) as the upper phase, 20% Ficoll as the middle phase and 30% Ficoll as the lower phase. The duration of the gradient centrifugation was 20 min at 5000 rpm. The discs were enriched at the interphase between 10% and 20%. Imaginal discs were washed once with PBS to clean them from residual Ficoll. All Ficoll solutions were made with PBS. Libraries were prepared using the Illumina TruSeq ChIP Sample Prep Kit (IP-202-1012, Illumina).