Suppression of eukaryotic translation termination by selected RNAs

Using selection-amplification, we have isolated RNAs with affinity for translation termination factors eRF1 and eRF1(.)eRF3 complex, Individual RNAs not only bind, but inhibit eRf1-mediated release of a model nascent chain from eukaryotic ribosomes, There is also significant but weaker inhibition of eRF1-stimulated eRF3 GTPase and eRF3 stimulation of eRF1 release activity, These latter selected RNAs therefore hinder eRF1(.)eRF3 interactions, Finally, four RNA inhibitors of release suppress a UAG stop codon in mammalian extracts dependent for termination on eRF1 from several metazoan species. These RNAs are therefore new specific inhibitors for the analysis of eukaryotic termination, and potentially a new class of omnipotent termination suppressors with possible therapeutic significance.