Fixing cells

1. Suspend 1-2x 10⁶ cells in 1 ml of PBS.

2. Fix cells with 1-2% paraformaldehyde in PBS for 15 minutes.

3. Wash the cells in PBS three times for 5 minutes.

4. Resuspend cells in 0.5 ml PBS.

5. Add cells to 5 ml of ice-cold 70% ethanol.

6. Cells can be stored in 70% ethanol at -20 °C.

Labeling and nuclei staining are similar to the protocol described in TUNEL.