Viral Codon Usage and the Host Transfer RNA

The expansion of viruses within cells requires efficient viral protein production. Counterintuitively, many viral genomes are enriched in suboptimal codons, which are typically associated with reduced protein outputs. Recent research using chikungunya virus (CHIKV) as a prototype model highlights the role of host transfer RNA (tRNA) modifications, collectively known as the tRNA epitranscriptome, in resolving this paradox. Upon infection, CHIKV triggers a DNA damage stress response that ultimately leads to changes in the tRNA epitranscriptome. These changes reprogram codon optimality, selectively enhancing the translation of specific suboptimal codons that are highly enriched in both host stress response genes and the viral genome. Hence, CHIKV codon usage optimally aligns with the tRNA modification landscape in infected cells. We propose that this interplay between viral codon usage, stress responses, and tRNA modifications is a shared strategy among viruses beyond CHIKV. Targeting this interplay may pave the way for the development of broad-spectrum antiviral therapies.