The translational efficiency of mRNA molecules transcribed from plasmid DNA transfected into COS-1 monkey cells can be increased 10- to 20-fold by the coexpression of the adenovirus virus-associated RNAs I and II. Experiments described here demonstrate a similar increase in translational efficiency by the addition of 2-aminopurine, an inhibitor of double-stranded RNA-activated protein kinase, to the culture medium. Both virus-associated RNA and 2-aminopurine presumably exert their effect by alteration of the functional level of eucaryotic initiation factor-2. The translational stimulation mediated by both means is shown to be restricted to the plasmid-derived mRNAs because there is no qualitative or quantitative alteration in host protein synthesis. The results are consistent with models invoking a localized activation of double-stranded RNA-activated kinase leading to a translational block.
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