library_construction_protocol: Cells were cooled using ice-cold PBS with 0.1 mg/ml cycloheximide, then scraped, pelleted and flash frozen after aspiration of the supernatant. Cells were then lysed and riboseq libraries were prepared as described in McGlincy and Ingolia, 2017, except that RNase H-based rRNA depletion was used (Adiconis et al 2013), and libraries were made using an iCLIP-related protocol. For quantseq, a small aliquot was kept aside before RNase I digestion. RNA was extracted after pelleting of ribosomes through a sucrose cushion with trizol and zymo RNA miniprep columns. For quantseq, RNA was trizol extracted from the above frozen lysates. iCLIP related protocol (Huppertz et al 2014) was used for Riboseq. Lexogen Quantseq Fwd was followed for Quantseq.