Bulk extracts of histone extracts from various cell lineages were probed with streptavidin (panel A), anti-biotin (panel B), and the loading and transfer controls coomassie blue (panel C), anti-H3 (panel D), and anti-H4 (panel E). Panel F: Histones from HeLa cells were extracted with H2SO4+TCA+acetone/HCl+acetone. Ten or five microgram of histones were loaded per well. Blots were blocked with PBS containing 5% BSA. After probing with horseradish peroxidase-conjugated anti-biotin or Nutravidin, the blots were washed for 6 hrs, and exposed to autoradiography film for 1 min.