Disome profiling of rocaglamide A treatment in HEK293FT cells

For the past decade, extensive studies of translation have produced a vast amount of ribosome profiling data, an insightful resource for mining of critical details about the dynamics of translation regulation under various biological contexts. Previously, Rocaglamide A (RocA), an anti-tumor heterotricyclic natural compound, has been shown to selectively inhibit translation initiation of a large group of mRNA species by clamping eukaryotic translation initiation factor 4A (eIF4A) onto poly-purine motifs in the 5’ un-translational regions (5’UTRs). However, re-analysis of the previous ribosome profiling datasets revealed an unexpected shift of the ribosome occupancy pattern during early translation elongation upon RocA treatment in various types of cells, for a specific group of mRNA transcripts without poly-purine motifs over-presented in their 5’UTRs. Such perturbation of the translation elongation dynamics can be attributed to the blockage of translating ribosomes due to the binding of eIF4A to the poly-purine sequence in coding sequences. This new mode of action of RocA, which is complementary to the canonical function inhibiting translation initiation, selectively interfere with the translation of the genes involved in fundamental processes such as ATP synthase, mitochondrial respiratory chain complex, et al. In summary, re-analyses of previous ribosome profiling data has revealed the complete dual modes of RocA in blocking translation and thus underlying the potent anti-tumor effect Comparative distribution of the disome protected fragments under RocA and DMSO treatment based on disome profiling data analyses.