title: GSM7913992: K562, dp300, H3K4me3_Sp,ChIP, rep1; Homo sapiens; ChIP-Seq
library_construction_protocol: Nuclei were digested with 100 units of MNase at 37°C for 15 min. Mono or di-nucleosomes sized chromatin was incubated with antibodies for 3 h at 4°C and recovered with protein A agarose beads. ChIP DNA (10 ng for H3K4ac, H3K4me1, H3K4me2, and H3 and and 5 ng for H3K4me3) was processed using NEBNext Ultra II DNA Library Prep Kit (New England Biolabs) with manufacturer's instructions. The ends of ChIP DNA were repaired by NEBNext Ultra II End Prep enzyme mix and ligated with NEBNext adaptors. Adaptor-ligated DNA was selected at 175 bp size using NEBNext sample purification bead and amplified using the adaptor primers. The fragments are purified using NEBNext sample purification beads.