Role of Host tRNAs and Aminoacyl-tRNA Synthetases in Retroviral Replication.

The lifecycle of retroviruses and retrotransposons includes a reverse transcription step, wherein double-stranded DNA is synthesized from their RNA genomes for subsequent insertion into the host genome. Retroviruses and retrotransposons commonly appropriate major components of the host cell translational machinery, including cellular tRNAs, which are exploited as reverse transcription primers. Non-priming functions of tRNAs have also been proposed, such as in HIV-1 virion assembly, and tRNA-derived fragments may also be involved in retrovirus and retrotransposon replication. Moreover, host cellular proteins regulate retroviral replication by binding to tRNAs and thereby affecting various steps in the viral lifecycle. For example, in some cases, tRNA primer selection is facilitated by cognate aminoacyl-tRNA synthetases (ARSs), which bind tRNAs and ligate them to their corresponding amino acids, but also have many known non-translational functions. Multi-omic studies have revealed that ARSs interact with both viral proteins and RNAs and potentially regulate retroviral replication. Here, we review the currently known roles of tRNAs and their derivatives in retroviral and retrotransposon replication and shed light on the roles of tRNA-binding proteins such as ARSs in this process.