Fig. 1.
Histone amino-terminal tail acetylation is required for nucleosome disassembly. (A) HAT assay reveals that H3 and H4 are highly acetylated in the evicted (supernatant) fraction. The nucleosome eviction assay was performed as shown schematically in Fig. S1A. Briefly, the promoter template was assembled with wild-type core histones, and nucleosome eviction was analyzed following the addition of highly purified Tax, pCREB, p300, hNap1, and acceptor DNA; in the absence or presence of [14C] Ac-CoA. The purified proteins used in these assays are shown in Fig. S1B. The same gel was analyzed by Coomassie staining and PhosphorImage analysis. Molecular weight markers (M) are indicated. (B) Schematic of the four core histone N-terminal tails showing the positions of the lysine to arginine (K → R) point mutations (43). (C) Lysines in the N-terminal core histone tails are required for Ac-CoA-dependent nucleosome eviction. Chromatin was assembled with either wild-type or K → R histone octamers. Nucleosome disassembly was assayed as described in A and Fig. S1A (using nonradiolabeled Ac-CoA). Dashed lines demarcate the lanes. Asterisk denotes contaminating streptavidin (from the Dynabeads®) that comigrates with H4.