Changes in histone H1 composition during differentiation of mouse myeloid leukemia cells

The possible change due to dexamethasone treatment in the relative amounts of two major subtypes of H1 histone, H1A and H1B, in mouse myeloid leukemia cells (M1 cells) during differentiation was examined. The relative amount of H1B decreased after dexamethasone treatment and reached about one-tenth that of H1A at the fully differentiated stage. These results contrast with the results reported for normal fibroblast cells and their neoplastic counterparts. Additional findings are that phosphorylation of H1 occurs almost exclusively in the H1B subtype and fluctuates following dexamethasone treatment.