In vitro histone acylation assay using fractionated HepG2 cell extracts. (a) Schematic diagram of the fractionation of HepG2 cell extracts and in vitro acylation assay using calf thymus histone. (b) In vitro histone acylation assays using fractionated cell extracts. 14C-labeled coenzyme A incorporation into histone proteins was assessed by autoradiography. The amounts of added substrate (calf thymus histone proteins) in each reaction were visualized by Coomassie Brilliant Blue (CBB). Molecular weights are indicated in the left side of the figure, and each histone position (histones H3, H2A/B, and H4) is indicated on the right side of the figure.