Nucleosome-like particles and acetylated histones occur near active promoters and
enhancers, and certain transcription factors can recognize their target sites on the surface of
a nucleosomein vitro; yet it has been unclear whether transcription factors can occupy target
sites on nucleosomes in native chromatin. We developed a method for sequential chromatin
immunoprecipitation of distinct nuclear proteins that are simultaneously cross-linked to
nucleosome-sized genomic DNA segments. We find that core histone H2A co-occupies …