Total RNA-seq libraries were prepared using SMART-Seq® Stranded Kit (Clontech) following the manufacturer's instructions. Poly(A) RNA-seq libraries were prepared using SMARTer ultralow input RNA cDNA preparation kit (Clontech). Nextera XT DNA library preparation kit (Illumina) was used for poly(A) RNA-seq cDNA fragmentation, adaptor ligation, and amplification according to the manufacturer's instructions. 