Fig. 11. Distribution of Me(3)K20H4 is dependent upon Suv 3(9)h1/h2 H3-specific HMTase activity. B is the merged image of A and C, and F is the merged image of E and G; DAPI is pseudocoloured red and Me(3)K20H4 green. Staining of Suv3-9 null cells with the anti-Me(3)K20H4 antibody shows that Me(3)K20H4 is distributed throughout the nucleoplasm (C), outside the DAPI-positive blocks of constitutive heterochromatin (A; merged image in B). In a mitotic nucleus from the Suv3-9 null cell line the Me(3)K20H4 is absent from centromeric heterochromatin (D). This is in stark contrast to a mitotic cell from wild-type mouse fibroblasts (H), where there is robust staining of the centromeric heterochromatin. In an asynchronous population of wild type cells, the staining of Me(3)K20H4 is variable (G), as previously described (see Figs 2 and 5), and present over the DAPI-positive blocks of heterochromatin (E; merged image in F).