巨大ウイルスがアメーバ宿主内で特殊な亜細胞環境を形成し、効率的な翻訳を実現する

Many eukaryotic viruses, including amoeba-infecting mimiviruses, have codon usage that deviates from their hosts. However, codon usage patterns that align with the cellular tRNA pool enable efficient translation. How these viruses cope with the mismatch between tRNA supply and demand is unclear. Here we show that Acanthamoeba polyphaga mimivirus (APMV) generates a subcellular area to translate viral mRNAs. tRNA sequencing showed that the tRNA pool was not substantially altered during the infection, even though the virus encodes tRNA genes. Using in situ labelling, we found that viral mRNAs and newly synthesized proteins were localized in the periphery of the viral factory, suggesting that APMV creates a discrete subcellular environment to facilitate translation. Frequently used codons in viral mRNAs had higher tRNA accessibility than the same type of codons in amoeba mRNAs. Our data show how local translation assists the virus in overcoming the mismatch between tRNA supply and demand.