A hypophosphorylated form of Pol II remains associated with the autosomes, but not the X chromosomes, in late primordial germ cells (PGCs). (A) Pol II is still on DNA late PGCs. DAPI, red; Pol II (8WG16 antibody) staining, green; PGL-1 staining, blue. Lower panels show enlarged PGCs and the separated channel for Pol II staining in grayscale. Arrows point to regions in the PGCs that lack Pol II staining. (B) The regions of Pol II exclusion overlap with regions lacking MES-4, which specifically associates with the autosomes at all stages that have been examined. Arrows point to the region of X chromosomes. Scale bars: (A) 10 μm; (B) 3 μm.