design: RNA was isolated with 2 rounds of Oligo d(T) magnetic bead purification; cDNA was generated by RT-PCR followed by purification with RNAClean XP beads; second-strand synthesis was performed followed by purification with Sera-Mag SpeedBeads. Libraries were then subjected to blunting, A-tailing and adapter ligation using barcoded adapters and digested with uracil DNA glycosylase to generate strand-specific libraries. Libraries were PCR-amplified for 12-15 cycles and size-selected for 200-350 bp fragments by gel extraction, then sequenced.