Modified ribosome profiling in humans and zebrafish revealed that collided ribosomes emerge at specific motifs including Pro-Pro/Gly/Asp and Arg-X-Lys, and are rescued by eIF5A.
The study identifies specific RNA and amino acid motifs that cause ribosome collisions and highlights the role of electrostatic interactions and eIF5A in resolving these pauses.
Ribosome movement is not always smooth and is rather often impeded. For ribosome pauses, fundamental issues remain to be addressed, including where ribosomes pause on mRNAs, what kind of RNA/amino acid sequence causes this pause, and the physiological significance of this attenuation of protein synthesis. Here, we survey the positions of ribosome collisions caused by ribosome pauses in humans and zebrafish using modified ribosome profiling. Collided ribosomes, i.e., disomes, emerge at various sites: Pro-Pro/Gly/Asp motifs; Arg-X-Lys motifs; stop codons; and 3' untranslated regions. The electrostatic interaction between the charged nascent chain and the ribosome exit tunnel determines the eIF5A-mediated disome rescue at the Pro-Pro sites. In particular, XBP1u, a precursor of endoplasmic reticulum (ER)-stress-responsive transcription factor, shows striking queues of collided ribosomes and thus acts as a degradation substrate by ribosome-associated quality control. Our results provide insight into the causes and consequences of ribosome pause by dissecting collided ribosomes.
Han et al. (2020) studied Ribosome collision. Modified ribosome profiling was evaluated on Positions of ribosome collisions. Modified ribosome profiling in humans and zebrafish revealed that collided ribosomes emerge at specific motifs including Pro-Pro/Gly/Asp and Arg-X-Lys, and are rescued by eIF5A.