Ribosome profiling study of eIF5A depletion strain

The eukaryotic translation factor eIF5A, originally identified as an initiation factor, was later shown to promote translation elongation of iterated proline sequences. Using a combination of ribosome profiling and in vitro biochemistry, we report a much broader role for eIF5A in elongation and uncover a substantial function for eIF5A in termination. Ribosome profiling of an eIF5A-depleted strain reveals a global elongation defect, with abundant ribosomes stalling at many sequences, not limited to proline stretches. Our data also show accumulation at stop codons and in the 3’-UTR, suggesting a global defect in termination in the absence of eIF5A. Using an in vitro reconstituted translation system, we find that eIF5A strongly promotes the translation of novel stalling sequences and increases the rate of peptidyl-tRNA hydrolysis more than 17-fold. We conclude that eIF5A functions broadly in elongation and termination, rationalizing its great cellular abundance and essential nature. 8 biological samples are included in the study (8 ribosome footprinting samples). These include wild-type and eIF5A depletion strains (with biological replicates). Also included are ribosome footprint profiling after high salt treatment.