Cells were trypsinized and collected by spin at 300g for 5 min. Then cell pellets were snap-freezed We performed native chromatin immunoprecipitation (ChIP) as described previously (Lorzadeh et al., 2016). Libraries were constructed using an Agilent Bravo automated liquid handling platform. Illumina sequencing libraries were generated by end repair, 3' A-addition, and Illumina sequencing adaptor ligation.