design: SMRTbell library were prepared from polyA-selected mRNA samples with Oligo(dT) magnetic beads under the instruction of SMARTer PCR cDNA Synthesis Kit (Clontech, #634925). After PCR amplification, the product was separated by BluePippin selection into cDNA fractions of 1-10K length. After generated using Template Prep Kit (PacBio, #100-259-100) according to the standard protocol, both SMRT bell libraries were quantitated by Qubit 2.0 (Invitrogen) and detected inserted fragments by Agilent 2100 (Agilent). Then sequencing primers and sequencing enzymes were combined to SMRT template in proportion for SMRT sequencing on a PacBio Sequel II platform with 60 G data generation in each sample.