Selective Translation of Mengovirus RNA over Host mRNA in Homologous, Fractionated, Cell‐Free Translational Systems from Ehrlich‐Ascites‐Tumor Cells

The selective translation of viral RNA in mengovirus‐infected Ehrlich ascites tumor cells was investigated using fractionated translational systems whose macromolecular components were derived entirely from uninfected or virus‐infected cells. Both systems translate host mRNA from uninfected cells, host mRNA from virus‐infected cells, and mengovirus RNA. In competition experiments, where viral RNA and host mRNA were translated together in systems from uninfected cells, the relative amounts of virus‐specific and host‐specific proteins synthesized were proportional to the relative concentrations of the RNA templates. In systems whose components were obtained from virus‐infected cells, mengovirus RNA was preferentially translated. 70% of the selectivity found in the translational systems derived from infected cells was due to the initiation factor fraction, the remaining 30% to components of the pH 5 enzyme fraction. In addition, host mRNA isolated after virus infection is translated in vitro to a lower extent in the presence of mengovirus RNA than is host mRNA from uninfected cells.