library_construction_protocol: Lysates are clarified from sonicated nuclei and histone-DNA complexes are isolated with antibody for ChIP-seq.  RNA is harvested using Trizol reagent. Illumina TruSeq RNA Sample Prep Kit (Cat#FC-122-1001) is used with 1 ug of total RNA for libraries of RNA-seq. GRO-seq library is constructed by pull-down of BrU labelled nascent RNA which is then subjected to strand specifice library construction. CUT&Tag libraries are constructed from nuclei extraction and antibody binding, transposome tagmentation. ChIP-seq, RNA-seq libraries were prepared for sequencing using standard Illumina protocols. CUT&Tag libraries are prepared from directely PCR. GRO-seq library is prepared by strand-specific library construction.