design: mRNA of five fragments of different treatments were equimolary pooled for library construction using the NEBNext Ultra II Directional RNA Library Prep Kit for Illumina (New England Biolabs, U.S.A) according to the manufacturers protocol. Successful library construction was checked using a 5200 Fragment Analyzer System (Agilent Technologies, U.S.A.). Libraries were sent to Macrogen (South Korea) for 2 x 150bp sequencing on an Illumina HiSeq 2500 sequencing platform.