library_construction_protocol: Frozen drops were grinded to powder using cold mortar and pestle, and the powder is then incubated with 1% formaldehyde (diluted in M9) for a final volume of 15 ml each tube and gently rocked for 10´ at room temperature.  Crosslinking is stopped adding 0.125 mM Glycine. Crosslinked lysate was centrifuged 3 times (4000 G, 3´) and washed in PBS containing inhibitors of proteases. The lysate was resuspended with 10ml of ice cold SDS-buffer. After centrifugation (2000 G, 10´) supernatant was removed and the pellet resuspended with IP buffer. Chromatin was sonicated using Diagenode bioruptor sonicator. Centrifugation (20000 G 30´) was performed and supernatant collected. Chromatin was de-crosslinked for 3h at 65C. Pre-cleared chromatin was incubated ON at 4C with 3ug of antibody. Libraries for sequencing were prepared using NEBNext Ultra II DNA Library Prep Kit for Illumina (NEB E7645S) and Multiplex Oligos for Illumina (NEB E7335S, E7500S). Quality and size of the libraries were checked by Bioanalyzer (Agilent 2100 Bioanalyzer). 