library_construction_protocol: Cells were lyzed in Mammalian Polysome Buffer (Illumina) containing cyclohexamide to pause translation. Input mRNAs and RPFs were isolated according to the TruSeq Ribo Profile pipline (Illumina) with modifications. Ribosomal RNAs were depleted and  cDNA libraries were constructed by using the NEBNext Small RNA Library Prep Set (New England Biolabs). NEBNext Small RNA Library Prep Set (New England Biolabs)