Fig. 4

MacroH2A1 and chromatin density in chicken embryo germ cells. A Immunodetection of macroH2A1 (gray) and germ cell marker (red) in gonad tissue sections. DNA staining (cyan). Scale bar: 10 µm. Quantification of fluorescence intensity in germ and somatic cell nuclei is shown below. Number of analyzed nuclei in 6‑, 10‑, and 14‑day-old-embryos: for females, 43, 44, and 38 germ cells and 76, 45, and 30 somatic cells, respectively; for males, 25, 39, and 34 germ cells and 46, 60, and 60 somatic cells, respectively. B macroH2A1 nuclear distribution in chicken germ and somatic cells. Immunodetection of macroH2A1 (green) in cPGCs, ESCs, and CEFs. DNA staining (cyan). Scale bar: 5 µm. C macroH2A1 foci compared to pericentric heterochromatin. Immunodetection of macroH2A1 (green) and CENP‑T or H3K9me3 (magenta) in the nucleus of cPGCs. DNA staining (cyan). Scale bar: 5 µm. Box plots show the enrichment in CENP‑T and H3K9me3 (mean intensity in each focus compared to mean intensity in whole nucleus) for more than 100 foci. D Representative germ and somatic cell nuclei in gonadal tissue sections with DNA staining (gray). Stars indicate germ cell nuclei. Scale bar: 5 µm. E Quantification of chromatin density (measured as the intensity of the DNA staining by unit area) in germ and somatic cell nuclei. Number of analyzed nuclei in 6‑, 8‑, 10‑, and 14‑day-old embryos: for females, 311, 284, 308, and 489 germ cells and 1873, 1754, 1101, and 919 somatic cells, respectively; for males, 323, 241, 323, and 316 germ cells and 1899, 1220, 924, and 1069 somatic cells, respectively. F Ultrastructure of germ and somatic cell nuclei observed using transmission electron microscopy in 14‑day-old embryo gonads. Nuclei of germ (G) and somatic (S) cells are indicated. Scale bar: 1 µm. Magnified views of the nuclear envelope and the associated chromatin are shown