ChIP was performed as described elsewhere (Peters AH, et al. (2003) Mol Cell 12(6):1577–1589). The Libraries were generated using NuGEN Ovation Ultralow System V2 1–96 kit. ChIP-seq libraries were produced from as little as 1 ng of double-stranded DNA. The workflow consisted of three steps: end repair to generate blunt ends, adaptor ligation with optional multiplexing and PCR amplification to produce the final library.