Total RNAs were extracted with Qiagen RNeasy Mini kit (Cat. #74106) following vendor's protocol. An additional step of on column DNase I digestion was performed during RNA extraction in order to eliminate potential traces of genomic DNA (RNase-Free DNase Set, Qiagen, Cat. #79254). Kapa Biosystems Stranded RNA-seq Kit with RiboErase (HMR) (Cat. # KK8483) was used with 1 ug of total RNA for the construction of sequencing libraries according to recommended protocol. ERCC RNA Spike-In control Mix 1 (Life Technologies, Cat. #4456740) has been included during library prep to assess platform dynamic range and lower limit of detection. Desired library insert size was 200 bp. The size distribution of the final libraries were confirmed by electrophoretic analysis on an Agilent Bioanalyzer 2100 prior to sequencing. Libraries were sequenced on the Illumina Genome Analyzer following the manufacturer's protocols for RNA-seq with HiSeq2500 in Rapid Run Mode using the HiSeq Rapid SBS v2 flow cell.