title: GSM6925678: 2-cell embryo, AS, input; Mus musculus; ChIP-Seq
library_construction_protocol: We performed ultra-low-input native chromatin immunoprecipitation sequencing (ULI-NChIP-seq) using early embryos according to a previous method [39]. Briefly, 150 2-cell embryos were washed three times with wash solution (PBS containing 0.5% BSA), and then the zona pellucida was removed with Tyrode's solution.  After embryos were dispersed into a single blastomere through pipetting, blastomeres were moved into the nuclear isolation buffer and the chromatin was digested by MNase for 7 min at 25°C. Next, samples were incubated with Dynabeads Protein G, which was pre-incubated with 0.5 μg of H3K27ac antibody (Abcam, ab4729) for 6 h at 4°C. After two washes with low salt wash buffer and high salt wash buffer, DNA was released in elution buffer for 2 h at 65°C, and then extracted using phenolchloroform-isoamyl alcohol (25:24:1). DNA library was generated using KAPA Hyper Prep Kit (Roche), and sequenced by Illumina NovaSeq 6000 system.