PI staining for FACS

Keep culture supernatant (contains floating apoptotic cells)
Harvest adherent cells using trypsin
Spin 1000 rpm, 4minWash with PBS x2Add 1ml 70% EtOH. Resuspend cells
Fix at 4C for 1h- 7days
Spin cells 1000 rpm, 4min
Wash with PBS x2
Add 100ul of 100ug/ml ribonuclease A for 5min RT
Add 400ul propidium iodide (50ug/ml) for 30min dark
Run FACS