library_construction_protocol: Cells were fixed with 1% formaldehyde for 10 minutes. After quenching and cell lysis, chromatin was sonicated using a Bioruptor Pico sonication device. ChIP-seq libraries were prepared using the NEBNext® Ultra™ II DNA Library Prep kit (NEB, Cat E7103). 10 ng of DNA was used as starting material for input and ip samples. Libraries were amplified using 13 cycles on the thermocycler. Post amplification libraries were size selected at 250-450bp in length using Agencourt AMPure XP beads from Beckman Coulter. Libraries were validated using the Agilent High Sensitivity DNA Kit by Agilent 2100 Bioanalyzer.