Validation of knockout cells. a Immunostaining with HP1α and HP1β antibodies on WT, HP1α KO, and HP1β KO ESC colonies surrounded by MEFs (examples are marked by asterisks) as feeder layer. ESC colonies not easily detectable are marked with a dashed line. Scale bars = 25 μm. b Western blots for HP1β in WT and HP1β KO ESCs and EBs. c Co-staining with H3K9me3 antibody and DAPI in WT, HP1α KO, and HP1β KO ESC colonies surrounded by MEFs as a feeder layer. ESC colonies are marked with a dashed line. Scale bars = 14 μm. The DAPI staining and H3K9me3 foci allow visualization of the global DNA organization and chromocenter organization. d Fluorescence recovery after photobleaching (FRAP) analysis of histone H1 fused to GFP in WT and HP1β KO ESCs (n = 10). (PDF 5.30 mb)