ChIP-qPCR for Epigenetic Markers

Chromatin immunoprecipitation was performed as previously described [40 (link)]. Briefly, the cells were incubated with 1% formaldehyde for cross-linking, followed by shearing. The chromatin solution was obtained by centrifugation at 13,000 rpm at 4 °C rpm for 20 min. A small portion (5%) of the chromatin solution was reserved as input DNA, and the remaining solution was incubated with the primary antibodies and protein A agarose/salmon sperm (Millipore, #16-157) overnight at 4 °C. Next, the chromatin fragments were de-crossed from the proteins and eluted to be subjected to qPCR using primers listed in Table 2. Anti-HP1γ (Millipore, 05-690), anti-trimethyl Histone H3 Lys9 (Millipore, 07-442), anti-G9a (Abcam, ab40542), and anti-Suv39h1 (Abcam, ab12405) were used for ChIP.