| 1) Aspirate and discard the culture medium from the cells. | |
| 2) Wash the cells once with 1 mL sterile PBS to remove residual medium. | |
| 3) Add 500 µL of RNA lysis buffer directly onto the cells in the dish. | |
| 4) Pipette up and down 5–10 times to lyse and homogenize the cells completely. | |
| 5) Transfer the lysate into a sterile RNase-free 1.5 mL microcentrifuge tube. | |
| 6) Add an equal volume of 70% ethanol to the lysate and mix gently by pipetting. | |