FIGURE 4.

Acr inhibits N-terminal tail acetylations of newly synthesized histones. A, BEAS-2B cells were exposed to various concentrations of Acr in serum-free medium for 2 h. Total histones were prepared by acid extraction and subjected to Western blot. No marked decrease of histone modification was observed in three independent experiments. B, experimental scheme for preparation of cell fractions. C, cytosolic cell fractions, nuclear extracts, and soluble chromatin fractions were isolated from BEAS-2B or A549 cells treated with or without Acr for 2 h and then subjected to Western blot. The bar graphs show relative quantification of histone modification levels normalized to H3. The data shown are the mean ± S.D. (error bars) from three independent experiments. *, p < 0.05; **, p < 0.01. Western blot analyses show drastic decrease of cytosolic H4K12Ac, H3K9Ac, and H3K14Ac by Acr exposure. D, whole cell lysates were prepared from Acr-treated and control cells and subjected to Western blot with antibodies against HAT1, a histone acetyltransferase specific for free histone H4 Lys-5 and -12. No decrease in HAT1 expression level was observed in two independent experiments. Coomassie Blue staining was used as the loading control.