ChIP was performed as previously described (Shah, P.P. et al. 2013), except that chromatin was sheared to an average size of <500 bp using the Covaris S220 Ultrasonicator. Equal aliquots of sonicated chromatin from undifferentiated and differentiated CAD neurons were used per immunoprecipitation reaction, and 10% of the amount was saved as input. Immunoprecipitation was performed using protein A Dynabeads (Life Technologies). Sequencing libraries were prepared using NEBNext Ultra library preparation procedure, and then assessed for quality and quantity by BioAnalyzer (Agilent) and qPCR (Kapa Biosystems).