c-myc protein expression during cell cycle phases in differentiating HL-60 cells.

We examined c-myc protein expression in cell cycle phases during differentiation induction of HL-60 cells by flow cytometry using an indirect immunofluorescence method. In exponentially proliferating HL-60 cells, c-myc protein was expressed in a cell cycle dependent manner. During the differentiation induction of HL-60 cells with dimethylsulfoxide (DMSO), c-myc protein was rapidly down-regulated in the G1/0 specific phase prior to the appearance of differentiation associated markers. Our results indicate that c-myc protein functions in the G1/0 specific phase in cellular differentiation, and the rapid down-regulation of c-myc protein in G1/0 phase is closely associated with initial differentiation programs.