A viral RNA uses conformational rearrangements of a dynamic tRNA-like structure to hijack cellular machinery

Abstract

RNA viruses use multifunctional, structural elements in their untranslated regions (UTRs) to hijack cellular machinery, but detailed mechanisms are often difficult to understand due to the dynamic nature of RNA structure. We used cryo-EM to visualize a mysterious 55kDa tRNA-like structure (TLS) at the 3 end of the brome mosaic virus (BMV) genome that is recognized and aminoacylated by cellular tyrosyl-tRNA synthetase (TyrRS) and that plays critical functions in the viral life cycle. Although the BMV TLS has served as a model system of RNA structure-function relationships for decades, the structural nature of its tRNA-mimicry had remained elusive.