[Simultaneous analysis of c-myc protein expression and cell cycle with monoclonal antibody and flow cytometry]

C-myc protein plays an important role in the regulation of cell proliferation and differentiation. In this paper, c-myc protein and DNA were doubly stained and analysed simultaneously with flow cytometry (FCM). At first, three fixatives, ethanol, methanol and paraformaldehyde, were examined using HL-60 cells, among which 50% ethanol was found to be optimal for each staining. After fixation, the cells were stained with a monoclonal antibody against c-myc protein, followed by DNA staining with PI. Simultaneous analysis demonstrated that c-myc protein was constantly expressed through the cell cycle and that the protein amount at the G2 + M phases was 1.5 times higher than that at the G1 phase. Further, the differentiation study with TPA and RA revealed that the growth, S phase and also c-myc protein expression were suppressed during the differentiation.