library_construction_protocol: Cells were treated briefly with CHX, flash-frozen, then lysed. RNA-seq samples were rRNA-depleted and DNase-treated. Ribo-seq samples were footprinted to extract ribosome-protected fragments, rRNA-depleted, and ran out on a TBE-Urea PAGE gel to isolate 27-30 nt fragments (RPFs). The extracted RNA fragments were treated with PNK and cleaned. RNA-seq samples were generated using KAPA RNA Hyperprep library kit protocol, with Illumina compatible IDT-UBI adapters (KAPA Dual-Indexed Adapter Kit [Roche]). Ribo-seq samples were generated using QIASeq miRNA Library preparation kit (Qiagen), with indexes supplied in QIAseq miRNA NGS 96 Index IL plate kit (Qiagen).