Genes for tRNA recycling are upregulated in response to infection with Theiler's mouse encephalitis virus

The concept of tRNA recycling has recently emerged from the studies of ribosome-associated quality control. Therein tRNase Z^S removes the 2', 3'>p from the ANKZF1-cleaved tRNA and the subsequent TRNT1 action re-generates the intact tRNA. To know the roles of the tRNA recycling in vivo, we investigated how viral infection affects the tRNA recycling system by analyzing the mRNA levels of tRNase Z^S and TRNT1. We found that both genes in HeLa cells are upregulated in response to infection of Theiler's mouse encephalitis virus but not to that of an influenza A virus. Upregulation was also observed in cells infected with encephalomyocarditis virus with reduced efficiency. The levels of the IFN-β mRNA appeared to positively correlate with those of the tRNase Z^S and TRNT1 mRNAs. The tRNase Z^S gene may be regulated post-transcriptionally in the cells infected with Theiler's mouse encephalitis virus.