Total RNA was extracted according to the method of Chomczynski and Sacchi using Trizol Reagent (Invitrogen Co., Carlsbad,
CA, USA)[20]. The extracted RNA was then treated with RNasefree DNase I (TaKaRa, Shuzo, Kyoto, Japan). RNA concentrations
were estimated by Nanodrop spectrophotometry at 260 nm and
their purities were checked by determining the absorption ratios
at 260/280 nm. The quality of extracted RNA was assessed by
electrophoresis at 1% agarose-gel containing Ethidium Bromide.
First-strand cDNA was synthesized from 100 ng of total RNA using
an oligo (dT) primer, random hexamers and a commercially available kit (AccuPower
®
RocketScriptTM
RT PreMix) according to
manufacturer’s instructions.