Alterations of Histone Phosphorylation in Rat Spleen Cells After Treatment with the Aromatic Amine, 4,4′‐Methylene‐bis(2‐chloroaniline)

Alterations of the phosphorylation pattern of histones by the carcinogen, 4,4′‐methylene‐bis(2‐chloroaniline) (MOCA) were investigated using rodent spieen cells. Spleen cells were isolated from Sprague–Dawley rats and treated with either 5, 10, 25, or 50 μM MOCA or acetone vehicle Controls for 1, 2, 4, or 8 hours. Cells were incubated with 32 P‐phosphoric acid, and histones from these cells were fractionated utilizing two‐dimensional polyacrylamide gel electrophoresis. Marked stimulation of histone phosphorylation was observed with the 10 μM MOCA treatment. A transient decrease in histone phosphorylation was observed at the 1 and 2 hour time points followed by a marked stimulation at 4 hours.