Major satellite replication is specifically advanced by 5-azacytidine treatment. (a) Replication timing of 5-azacytidine treated (black bars) and untreated ES cells (white bars). The mean values and standard error of at two independent experiments are shown. (b) Demethylation index (HpyCh4IV digested to undigested genomic DNA) of the major satellite in untreated (OS25), 5-azacytidine-treated and Dnmt1 KO ES cells. Sox2 (no HpyCh4IV site) serves as an internal control. Diagrams show the positions of primers and HpyChIV site. The standard deviation is shown in brackets.