Cells were first crosslinked by formaldehyde, then digested with Mnase, then sonicated in N-lauroyl-sarcosine containing buffer to dissolve the chromatin. The clarified chromatin were immunoprecipitated with agarose conjucated with antibodies. Libraries were prepared according to NEBNext Ultra DNA Library Prep Kit for Illumina (E7370L) and were sequenced using HiSeq2000 or Nova-seq.