Effect of hexamethylene bisacetamide on the commitment to differentiation of murine erythroleukemia cells.

Friend virus-transformed murine erythroleukemia cells express the program of erythropoietic differentiation under the influence of the previously described, potent inducing agent, hexamethylene bisacetamide. Commitment to differentiation, defined as the ability to continue the processes of differentiation in the absence of inducer, has been examined at the single-cell level, with a combination of suspension and cell-cloning techniques. Recruitment of committed cells is shown to occur prior to the detectable accumulation of hemoglobin or the appearance of morphological changes characteristic or erythroid maturation. The stability of the commitment of murine erythroleukemia cells to differentiate is found to be dependent upon both the concentration of hexamethylene bisacetamide and the duration of exposure to the inducing agent. Under conditions less than optimal for induction, a single cell can give rise to a colony containing both differentiated and undifferentiated cells. On the basis of these findings, it is suggested that fully stabilized differentiation, in addition to the previously demonstrated requirement for the inducing agent to be present during a cell-cycle S phase, involves subsequent stabilizing event(s) caused by a direct or indirect action of the inducing agent.