MOESM1 of Silencing markers are retained on pericentric heterochromatin during murine primordial germ cell development MagarakiAristea HeijdenGodfried Sleddens-LinkelsEsther MagarakisLeonidas CappellenWiggert PetersAntoine GribnauJoost BaarendsWilly EijpeMaureen 2017 Additional file 1. Immunofluorescent analysis of HP1α in paraffin sections using regular and extended fixation protocols. A In E10.5 embryos, HP1α (green) is enriched at pericentric heterochromatin, but its levels are lower in PGCs compared to somatic cells. From E11.5 onwards, HP1α signal is depleted from DAPI (blue)-dense regions in PGCs. B Results were similar to A when using extended fixation conditions. However, at E11.5 some PGCs could be detected with some signal of HP1α still present at the pericentric heterochromatin (marked by arrowhead). Note that in E13.5 male gonads HP1α could not be reproducibly detected in somatic cells, in both A and B. For each stage, two embryos were analysed per fixation protocol and at least 20 nuclei were recorded. E10.5 and E11.5 PGCs were marked with OCT4 (red). E13.5 male and female germ cells were identified by the presence of DDX4/MVH (red). Representative images are shown with germ cells highlighted by dashed yellow circles, and scale bars represent 5 μm.