A novel function for eukaryotic elongation factor 3: Inhibition of stop codon readthrough in yeast

Eukaryotic elongation factor 3 (eEF3) is one of the essential yeast ribosome-associated ATP-binding cassette type F (ABCF) ATPases. Previously, we found that eEF3 stimulates release of mRNA from puromycin-treated polysomes. In this study, we used a cell-free cricket paralysis virus (CrPV) internal ribosome entry site (IRES)mediated firefly luciferase bicistronic mRNA translation system with yeast S30 extract. When eEF3 was partially removed from the crude extract, the product from the downstream ORF was increased by the readthrough of a UAA stop codon in the upstream ORF. eEF3 enhanced the release of luciferase from the polysome by eukaryotic release factor (eRF)1 and eRF3. These results suggest that eEF3 is a factor that assists eRFs in performing normal protein synthesis termination in yeast.

Automated summary

Eukaryotic elongation factor 3 (eEF3) stimulates the release of mRNA from puromycin-treated polysomes. When eEF3 is partially removed from the crude extract, a UAA stop codon readthrough occurs, leading to an increase in the downstream ORF product. eEF3 enhances the release of luciferase from polysomes by eukaryotic release factor (eRF)1 and eRF3. These findings suggest that eEF3 assists eRFs in performing normal protein synthesis termination in yeast.