Total RNA was extracted from the tissues using Trizol (Invitrogen, Carlsbad, CA, USA) according to manual instruction. After the total RNA passed quality inspection, the magnetic beads connected to Oligo (dT) were used to enrich the eukaryotic messenger RNA (mRNA). The extracted mRNA was randomly interrupted into short fragments by RNA fragmentation buffer. Using fragmented mRNA as a template, a single-stranded complementary DNA (cDNA) was synthesized using random hexamers with 6 bases. Then buffer, dNTPs, RNaseH, and DNA polymerase I (Pol I) were added for double-strand cDNA synthesis. Hieff NGS®DNA Selection Beads were used to purify double-strand products and perform fragment selection. Finally, PCR amplification was performed to obtain the final sequencing library. The final library was amplified with phi29 to make DNA nanoball (DNB) which had more than 300 copies of one molecular, DNBs were loaded into the patterned nanoarray and pair end 150 bases reads were generated on DNBSEQ-T7 platform at Tsingke Biotechnology Co., Ltd..