Translational efficiency: iridovirus early mRNAs outcompete tobacco mosaic virus message in vitro

Infection with the iridovirus, frog virus 3, results in the rapid inhibition of host cell protein synthesis and is correlated with activation of an eIF-2 kinase. Because phosphorylation of eIF-2 inhibits ternary complex formation and thus reduces the overall level of translation, it has been suggested that frog virus 3 messages escaped translational shut-off by outcompeting host messages for the remaining translational capacity of the cell. In this report, we show that frog virus 3 messages were more translationally competitive than highly efficient tobacco mosaic virus transcripts based on their relative resistance to inhibitors of initiation. This result strengthens the suggestion that the selective translation of frog virus 3 transcripts in virus-infected cells may be a reflection of their enhanced competitiveness.