mES cells cultured in 2i+LIF were collected, fixed for 10 min in 1% formaldehyde, and sheared using a Picoruptor.Histone-DNA complexes were isolated with antibody. Antibodies against Dzip3, Ring1B and ubH2A were prepared by immunizing rabbits in our laboratory. ChIP-seq libraries were prepared from ChIP samples using the ChIP-Seq Sample Prep kit (Illumina).