Acetylation on histones 3 (H3) and 4 (H4) in Lewis and Sprague-Dawley dextran sulfate sodium (5% DSS) treated rats. Tissue samples were obtained from the sigmoid colon of the animals. A: Representative bands of H4 and H3 acetylation as obtained by Western blotting. β-actin levels were measured to ensure equal protein loading. The results are representative of three independent experiments. B, C: Graphical analysis of data Lanes represent: (1) non-DSS treated Lewis rats (control), (2) DSS-treated Lewis rats, (3) non-DSS treated Sprague-Dawley rats (control) (4) DSS-treated Sprague-Dawley rats. Columns represent the mean ± SEM of three independent experiments (*p < 0.05). D: Histone 3 (H3) and histone 4 (H4) localisation in Peyer's patches of dextran sulfate sodium (DSS) treated Lewis rats. H3 is acetylated mainly in the mantle zone and H4 is acetylated throughout the surface of Peyer's patches to both mantle zone and germinal centre cells. In Peyer's patches of untreated animals no acetylation on either histone 3 or 4 was apparent. Micrographs are representative of two individual experiments for each strain. Isotype controls show no staining.