Total RNA was isolated and purified using TRIzol reagent (Invitrogen, Carlsbad, CA, USA) following the manufacturer's procedure. The poly(A) RNA was fragmented into small pieces using VAHTS Universal V8 RNA-seq Library Prep Kit for Illumina (Vazyme, China) under 94℃ 5min. Then the cleaved RNA fragments were reverse-transcribed to create the cDNA by VAHTS Universal V8 RNA-seq Library Prep Kit for Illumina (Vazyme, China), which were next used to synthesise U-labeled second-stranded DNAs with VAHTS Universal V8 RNA-seq Library Prep Kit for Illumina (Vazyme, China).