For all samples except for the transgenic Endog rats and the Endog knockout mice (see below), ribosome profiling was performed using the TruSeq Ribo Profile (Mammalian) Library Prep Kit (Illumina, San Diego, CA, USA), according to a TruSeq Ribo Profile protocol optimized for use on tissue material, as described previously [31, 96]. In short, ± 50–100 mg powdered tissue was lysed for 10 min on ice in 1 mL lysis buffer consisting of 1 ? TruSeq Ribo Profile mammalian polysome buffer, 1% Triton X-100, 0.1% NP-40, 1 mM dithiothreitol, 10 U ml ? 1 DNase I, cycloheximide (0.1 mg ml ? 1 ), and nuclease-free H2O.