Following centrifugation at 12,000 × g for five minutes,
the upper phase was recovered and incubated with the
same volume of isopropanol at 4°C for 30 minutes, and
then centrifuged for 15 minutes at 12,000 × g at 4°C. The
pellet was washed with 1 mL of absolute ethanol and centrifuged
for a further five minutes at 12,000 × g at 4°C.
Finally, the pellet was dried at room temperature and resuspended
in 20 μL RNAse free water, and stored at -70°C
until RT-PCR analysis took place.