Total RNA was extracted using Trizol reagent (ThermoFisher, USA) following the manufacturer's procedure. mRNA was purified from total RNA (2 μg) using mRNA Caprure Beads2.0 (Yeasen, CHN) with two rounds of purification. RNA fragments were reverse-transcribed to synthesize first-strand cDNA by reverse transcriptase, which were next used to synthesise second-stranded DNAs with E.coli DNA polymerase I, RNase H and dUTP Solution (Yeasen, CHN).  An A-base was then added to the blunt ends of each strand, preparing them for ligation to the indexed adapters. Each adapter contained a T-base overhang for ligating the adapter to the A-tailed fragmented DNA. Dual-index adapters were ligated to the fragments, and the ligated products were amplified with PCR Dual-index adapters were ligated to the fragments, followed by amplification with PCR. PCR amplification products were purified by Hieff NGS DNA Selection Beads (Yeasen, CHN) and subjuected to ssequencing on an Illumina Novaseq™ X Plus platform.