DNA synthesizing activity during induced differentiation in mouse myeloid leukemia (M1) cells

Mouse myeloid leukemia (M1) cells were induced to differentiate in vitro by treatment with dexamethasone. After 8 h of treatment, induction of phagocytic and lysozymic activities and depression of DNA synthesis started at the same time and proceeded irreversibly. DNA synthesis in the nuclear system reflected primarily DNA replication rather than repair and this activity declined during M1 cell differentiation.