Reconstitution of chromatosome arrays.

<p>(A) AvaI digests of chromatosome arrays carrying H4K16ac. Chromatosome arrays were reconstituted with increasing amounts of H1, purified by MgCl₂ precipitation and digested to monomers with AvaI. Mononucleosomes were separated from chromatosomes on native agarose gels and visualized by ethidium bromide stain. Faint additional bands may contain coprecipitating competitor DNA or multimers arising from incomplete AvaI digest. (kb: kilobases). (B) Analysis of the relative ratio of H1 to core histones in chromatosome arrays. Top: Chromatosome arrays from the H1 titration shown in A were loaded onto SDS gels and the protein content visualized by Coomassie stain. The gel of the acetylated chromatosome arrays is depicted. Bottom: Quantification of the relative ratio of H1 to core histones. The theoretically expected ratio of 0.24 for a 1:1 stoichiometry of H1 to octamers was not reached, presumably because the Coomassie staining did not linearly correlate with the molecular weight of the proteins <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0088411#pone.0088411-Tal1" target="_blank">[79]</a>. (kDa: kilodaltons; a.u.: arbitrary units).