Fig. 5

Setting of the germ-specific epigenetic signature during chicken embryo early development. Immunodetection of histone PTMs, macroH2A1, 5mC, and 5hmC (gray) in chicken embryos. Representative nuclei of PGCs identified with a germ cell marker (red) and somatic surrounding cells are shown. For 5hmC, additional labelling of RNA pol II was performed to locate nuclei when necessary. DNA staining (cyan). Scale bar: 10 µm. A In the blastoderm (stage EG&K X). B In the germinal crescent (stage HH4). C In blood vessels near the head (stage HH13). D At the genital ridges (stage HH15-17). E Quantification of fluorescence intensity for H3K9me3 in germ and somatic cell nuclei in stage HH15 to HH23 embryos. Number of analyzed nuclei in HH15-17, HH20, and HH23 embryos (two embryos per stage): 39, 46, and 54 germ cells and 157, 144, and 259 somatic cells, respectively. F Quantification of chromatin density (intensity of the DNA stain by unit area) in germ and somatic cell nuclei, for the same stage HH15 to HH23 embryos