Inhibition of translation by poliovirus: inactivation of a specific initiation factor.

Abstract

Translation of vesicular stomatitis virus (VSV) mRNA, like host mRNA translation, is inhibited in cells infected with poliovirus. To study the mechanism of poliovirus-induced inhibition of protein synthesis, extracts from poliovirus-infected and uninfected [human cervical carcinoma] HeLa cells were prepared. Poliovirus mRNA was translated in lysates from both infected and uninfected cells, while VSV mRNA was translated only in the lysate from unifected cells. Addition of purified translation initiation factors to the extract from infected cells showed that 1 factor, eIF-4B, could restore VSV mRNA translation in the infected lysate, but did not increase poliovirus mRNA translation. Further experiments involving translation of VSV mRNA in mixed extracts from poliovirus-infected and uninfected cells showed that there was not an excess of an inhibitor of VSV mRNA translation in the infected lysate, but an activity that caused a slow inactivation of eIF-4B was present in the infected lysate. Inactivation of eIF-4B appears to be the mechanism by which poliovirus infection causes a selective inhibition of translation.