ChIP was performed as previously described (Huang et al.,2013). Briefly, crosslinked cells was sonicated and incubated with protein A and protein G dynabeads (1:1 mix) and the indicated antibodies. Antibody bound DNA was subsequently washed with low salt wash buffer, high salt wash buffer, LiCl wash buffer once, respectively, and then TE wash buffer twice. ChIPed DNA was reverse-crosslinked and purified for DNA library construction followed by sequencing or ChIP-qPCR analysis. ChIP-Seq and RNA-Seq libraries were prepared for sequencing using standard Illumina protocols