library_construction_protocol: Total RNA was collected using TRIzol reagent (ThermoFisher, 10296010) according to the manufacture's instruction.  Purified RNA was quantified using Qubit4 Fluorometer (ThermoFisher).  1 µg of RNA was mixed with ERCC RNA Spike-In Mix (ThermoFisher, 4456740).  Ribosomal RNA was first depleted using NEBNext®rRNA Depletion Kit(NEB, E6310X). NEBNext®Ultra™II Directional RNA Library Prep Kit (NEB, E7760L)